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WO2002066228A1 - Process and filter system for continuous filtration of liquids - Google Patents

Process and filter system for continuous filtration of liquids Download PDF

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Publication number
WO2002066228A1
WO2002066228A1 PCT/EP2002/001502 EP0201502W WO02066228A1 WO 2002066228 A1 WO2002066228 A1 WO 2002066228A1 EP 0201502 W EP0201502 W EP 0201502W WO 02066228 A1 WO02066228 A1 WO 02066228A1
Authority
WO
WIPO (PCT)
Prior art keywords
filter
outlet
inlet
housing
rotating
Prior art date
Application number
PCT/EP2002/001502
Other languages
French (fr)
Inventor
Michel J. Ghossain
Original Assignee
Enka Tecnica Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Enka Tecnica Gmbh filed Critical Enka Tecnica Gmbh
Priority to EP02722073A priority Critical patent/EP1361948A1/en
Publication of WO2002066228A1 publication Critical patent/WO2002066228A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/50—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition
    • B01D29/52—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition in parallel connection
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/11—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements
    • B01D29/114—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements arranged for inward flow filtration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
    • B01D35/12—Devices for taking out of action one or more units of multi- unit filters, e.g. for regeneration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/254—Sealing means
    • B29C48/2545—Sealing means for filters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/255—Flow control means, e.g. valves
    • B29C48/2554—Flow control means, e.g. valves provided in or in the proximity of filter devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/27—Cleaning; Purging; Avoiding contamination
    • B29C48/2725—Cleaning; Purging; Avoiding contamination of filters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/27—Cleaning; Purging; Avoiding contamination
    • B29C48/2725—Cleaning; Purging; Avoiding contamination of filters
    • B29C48/273—Cleaning; Purging; Avoiding contamination of filters using back flow
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/50—Details of extruders
    • B29C48/69—Filters or screens for the moulding material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/50—Details of extruders
    • B29C48/69—Filters or screens for the moulding material
    • B29C48/691—Arrangements for replacing filters, e.g. with two parallel filters for alternate use
    • B29C48/6914—Arrangements for replacing filters, e.g. with two parallel filters for alternate use the filters being fitted on a rotatable or pivotable disc or on the circumference of a rotatable or pivotable cylinder
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/50—Details of extruders
    • B29C48/69—Filters or screens for the moulding material
    • B29C48/694—Cylindrical or conical filters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B7/00—Mixing; Kneading
    • B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
    • B29B7/58—Component parts, details or accessories; Auxiliary operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion

Definitions

  • the invention relates to a process and a filter system for continuous filtration of liquids, in particular viscous fluids such as molten polymers. It also relates to a filter system to carry out such a process.
  • the filtration of molten polymers is necessary while producing man-made fibers, film, etc.
  • the production processes require continuous flow of clean molten polymer. Impurities, such as contaminants and gels, tend to cause fiber breakage or film ripping during the spinning and orientation phases.
  • the diverter valves regulate the flow at the inlet and at the outlet of the system.
  • the valve at the inlet When switching from one filter housing to the second, the valve at the inlet is moved first, allowing a small portion of the flow to enter the fresh filter housing.
  • the valve at the outlet side remains unchanged.
  • a vent valve on the fresh filter housing is opened to allow the incoming product flow to fill the filter housing completely (venting or bleeding of the filter housing to come on-stream).
  • the vent valve is closed and the diverter valves at the inlet and at the outlet are moved simultaneously to force the complete product flow through the fresh filter housing, thus taking the first filter housing off-stream.
  • Filter systems with two filter housings and two diverter valves have an installed filter area equal to twice the filter area that is on-stream. Normally at least three complete filter housings are needed for continuous operation: one housing on-line, one housing on stand-by and one housing undergoing external cleaning and replacing of filter elements.
  • the diverter valves define the most critical parts of these double filter systems. It is particularly difficult to design and manufacture such valves absolutely free of gaps, dead flow areas, and areas with reduced flow velocity. In the filtration of molten polymers, such gaps and areas with different flow characteristics may lead to product degradation with subsequent production problems as described earlier.
  • filter systems with two filter housings and two diverter valves do not offer the flexibility to easily change the filtration area of the installed filters in case of production rate and/or filter rating change requirements. This would require a variety of housing sizes to accommodate a variety of production rates and filter ratings.
  • the primary object of the invention is to provide an apparatus and a process to continuously filter highly viscous fluids, in particular molten polymers and to overcome the disadvantages associated with the prior art.
  • Another object of the invention is to provide an apparatus and a process to narrow and minimize the residence time distribution of the flowing products.
  • Another object of the invention is to provide an apparatus and a process without the use of dedicated diverter valves.
  • Another object of the invention is to provide an apparatus and a process in which the entire available filtration area is used in the best way possible.
  • Another object of the invention is to provide an apparatus and a process in which the filter replacement would be achieved without flow interruption.
  • Another object of the invention is to provide an apparatus and a process in which only one bleeding and venting position is used.
  • Another object of the invention is to provide an apparatus and a process in which the filtration area may be changed without product flow interruption.
  • Another object of the invention is to provide an apparatus and a process in which the filtration area may be changed without changing the main apparatus assembly.
  • Another object of the invention is to provide an apparatus and a process with inherent safety of operation.
  • Another object of the invention is to provide an apparatus and a process in which the filter elements may be cleaned in place with the filtrate or another fluid reverse-flow.
  • the basis for the invention is the idea to have a filter system for highly viscous liquids, in particular molten polymers, that provides continuity, that offers a desired range of filter area on-stream, that eliminates the need for switch-over valves, that avoids prolonged residence times typical of bringing fresh filter area on-stream, that needs only one bleeding and venting position, and that offers inherently safe operation.
  • the invention defines a continuous filtration process. There is no interruption of operation foreseen whenever filter area gets exhausted. By rotating the filter assembly of the filter system, a small portion of the filter area is taken off-line, and then a fresh filter housing subassembly is introduced to the flow. During rotation, all but one of the multiple filter housings on-stream remain on-stream.
  • the invention includes a filter system with basically multiple filter housing subassemblies that are assembled and affixed around rotating inlet and outlet headers which in turn are fitted to fixed inlet and outlet collectors, forming a rotatable filter assembly that at the same time allows a uniform product flow to continuously pass through all of the installed filter housings during the normal filtration cycle, and the majority of the installed filter housings during the rotation cycle.
  • the rotatable filter assembly is rotated so that one housing subassembly is isolated from the flowing product and in turn gets depressurized through the depressurization port and then is removed or prepared for servicing and replacement of the filter element(s).
  • the rotatable filter assembly is rotated further to the one and only bleeding and venting position so that the newly serviced housing subassembly can be filled with product by bleeding through the unique inlet bleeding port and vented through the outlet vent before the rotatable filter assembly is rotated further in order to return it to the filtration service.
  • the rotation cycle would then be repeated for the service of the remaining housing subassemblies. Provisions to decrease the installed filtration areas are made by removing one or more housing subassemblies and replacing them with plugs. Provisions to increase the installed filtration areas are made by removing one or more housing subassemblies and replacing them with larger ones.
  • the product flow enters the main inlet and then gets distributed, by the inlet distributor flow channel, over any desired number (In this case 8 ports are shown in the drawings, this can be changed to any desired number of ports with corresponding housings) of inlet ports.
  • the flow then enters the filter inlet housing, which may have any desired type of opening, and then enters the filter element housings with one or more filter elements.
  • the flow then enters the filter element(s) and then the outlet housing, which may have any desired type of opening, then enters the outlet port.
  • the flow passing through the individual outlet ports is then collected in the outlet collector flow channel. The flow then exits the system through the main outlet.
  • the filter system according to the invention forces the product flow from its original flow path into the distributor serving multiple filter housings.
  • the size and shape of the distributor, as well as the size and the number of filter housings can be scaled according to individual needs, putting no fundamental restrictions on the filter area that may be installed.
  • the filtration process according to the invention lacks the need to install specific diverter valves.
  • the flow distribution over the multiple housings is affected by the fixed iniet distributor and outlet collector, which need not to be changed during any phase of operation.
  • multiple filter housing subassemblies say for example ten are on-stream. All these housings see, on the average ten percent of the incoming flow.
  • Bleeding takes place for only one fresh filter housing subassembly at any given time. Assuming ten percent of the flow is used for bleeding, then the bleeding flow portion takes only so much time, as is the typical residence time for the product in the filter during normal operation. After bleeding, one filter housing subassembly is turned off-stream; the just bled and vented housing subassembly is turned on-stream.
  • a provision to have one filter housing subassembly on stand-by mode is here considered. This allows the simultaneous removal and introduction of filter housing subassemblies without any change to the size of the installed area. This provision is realized by altering the design of the inlet distributor and outlet collector.
  • the invention offers the possibility to replace the exhausted filter area one fraction by fraction at a time.
  • a filter system according to the invention is provided in such a way that the system is self- cleaning by means of a reverse flow of clean filtrate or another suitable fluid through the exhausted filter area.
  • the changing of exhausted filter elements can be avoided by such a reverse flow of clean filtrate or another suitable fluid.
  • the critical design area of the filter system according to the invention is the sealing of the rotating inlet and outlet headers to the inlet fixed distributor and outlet fixed collector respectively. Given the specific process conditions, an appropriate seal would be provided to meet such conditions.
  • the seals may be made of a variety of elastomeric materials, or a special wear-resistant coating may be applied to a metal surface to affect a metal to metal sealing.
  • FIG. 1 Front view of filter assembly according to invention.
  • FIG. Top view of inlet assembly. Here the outlet assembly is not shown.
  • FIG. Bottom view of outlet assembly. Here the inlet assembly is not shown.
  • FIG 4. Top view of inlet assembly where filter housing subassemblies are rotated so that a filter housing subassembly is isolated for service. Here the outlet assembly is not shown.
  • FIG. Top view of inlet assembly where filter housing subassemblies are rotated further so that a filter housing subassembly is in the feed bleed position. Here the outlet assembly is not shown.
  • FIG 6. Top view of inlet assembly where filter housing subassembljes are rotated further so that the newly serviced filter housing subassembly is returned the to filtration service.
  • outlet assembly is not shown.
  • FIG 7. Bottom view of outlet assembly where filter housing subassemblies are rotated so that a filter housing subassembly is isolated for service. Here the iniet assembly is not shown.
  • FIG 8. Bottom view of outlet assembly where filter housing subassemblies are rotated further so that a filter housing subassembly is in the vent position. Here the inlet assembly is not shown.
  • IG 9. Bottom view of outlet assembly where filter housing subassemblies are rotated further so that the newly serviced filter housing subassembly is returned the to filtration service. Here the inlet assembly is not shown.
  • IG 10. Top view of inlet assembly where some of the filter housing subassemblies are removed to reduce the installed filtration area. .
  • IG 11. Bottom view of outlet assembly where some of the filter housing subassemblies are removed to reduce the installed filtration area.
  • IG 18 Top view of inlet assembly with the reverse flow outlet port. Here the outlet assembly is not shown. Bottom view of outlet assembly for the clean, filtrate reverse .flow case! .tfer ⁇ .the irrfet assembly is not shown. Top view of inlet assembly in the reverse flow mode. Here the outlet assembly is not shown. Bottom view of outlet assembly in the reverse flow mode. Here the inlet assembly is not shown. Bottom view of outlet assembly with the reverse flow inlet for another liquid reverse flow case. Here the inlet assembly is not shown. Bottom view of outlet assembly for another liquid reverse flow mode. Here the inlet assembly is not shown. Front view of the combined rotating inlet and outlet headers, and the combined inlet fixed distributor and outlet fixed collector.
  • FIG. 1 Schematically shows the filter system according to the invention with a main inlet (13) and a main outlet (14).
  • Attached to the main inlet (13) is an inlet fixed distributor (1) with an inlet distribution flow channel (5).
  • Attached to the main outlet (14) is an outlet fixed collector (2) with an outlet distributor flow channel (6).
  • a rotating inlet header (3) with inlet ports (17) is installed around the inlet fixed distributor (1).
  • a rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2).
  • Filter housing subassemblies comprising of an inlet housing (7) with a housing inlet channel (9), a filter element housing (12) in which the filter element(s) (11) are located, and an outlet housing (8) with a housing outlet channel (10), are affixed to the rotating inlet header (3) and the rotating outlet header (4).
  • the filter housing subassemblies along with rotating inlet header (3) and the rotating outlet header (4) form one whole rotatable filter assembly.
  • FIG. 2 Schematically shows the top view of the main iniet (13), the inlet fixed distributor (1) with the- inlet distributor flow channel (5) and the inlet bleed (15).
  • a rotating inlet header (3) with inlet ports (17) and oval port (21) is installed around the inlet fixed distributor (1).
  • the inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3).
  • FIG. 3 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the outlet vent (16) and depressurization port (20).
  • a rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2).
  • the outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4).
  • FIG. 4 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15).
  • a rotating inlet header (3) with inlet ports (17) and oval port (21 ) is installed around the inlet fixed distributor (1 ).
  • the rotating inlet header (3) is rotated so that one housing subassembly (7,11,12) is depressurized and isolated for service.
  • the inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3).
  • FIG. 5 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15).
  • a rotating inlet header (3) with inlet ports (17) is installed around the inlet fixed distributor (1 ).
  • the rotating inlet header (3) is rotated further so that the same housing subassembly (7,1 ,12) that was isolated as shown in FIG. 4 is in the bleed position.
  • the inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3).
  • FIG. 6 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15).
  • a rotating inlet header (3) with inlet ports (17) is installed around the inlet fixed distributor (1).
  • the rotating inlet header (3) is rotated further so that the same housing subassembly (7,11,12) that was bled as shown in FIG. 5 is returned to the filtration service.
  • the inlet housing (7) and the filter element housing (12) in which the filter element(s) (11 ) are located are affixed to the rotating inlet header (3).
  • FIG. 7 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the outlet vent (16) and depressurization port (20).
  • a rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2).
  • the rotating inlet header (3) is rotated so that one housing subassembly (8,11,12) is depressurized and isolated for service.
  • the outlet housing (8) and the filter element housing (12) in which the filter element(s) (11 ) are located are affixed to the rotating outlet header (4).
  • FIG, 8 Schematically shows the bottom view of the main outlet (1'4) ' tl otitlefrfijed coite * ctor.(2) wth- the outlet distributor flow channel (6) and the putlet vent (16) and depre'ss ⁇ rization port (20).
  • a rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2).
  • the rotating outlet header (4) is rotated further so that the same housing subassembly (8,11,12) that was isolated as shown in FIG. 4 and 7 is in the vent position.
  • the outlet housing (8) and the filter element housing (12) in which the filter element(s) (11 ) are located are affixed to the rotating outlet header (4).
  • FIG. 9 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the outlet vent ( 6) and depressurization port (20).
  • a rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2).
  • the rotating- outlet header (4) is rotated further so that the same housing subassembly (8,11,12) that was isolated as shown in FIG. 5 and 8 is in the bleed position.
  • the outlet housing (8) and the filter element housing (12) in which the filter element(s) (11 ) are located are affixed to the rotating outlet header (4).
  • FIG. 10 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15).
  • a rotating inlet header (3) with inlet ports (17) and oval port (21) is installed around the inlet fixed distributor (1).
  • the inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3).
  • Plugs ( 9) serve to block the flow to the inlet ports (17) so that some of the housing subassemblies (7,11,12) can be removed to reduce the installed filtration area.
  • FIG. 11 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the outlet vent (16) and depressurization port (20).
  • a rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2).
  • the outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4).
  • Plugs (19) serve to block the flow to the outlet ports (18) so that some of the housing subassemblies (8,11,12) can be removed to reduce the installed filtration area.
  • FIG. 12 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15).
  • a rotating iniet header (3) with inlet ports (17) and oval port (21) is installed around the inlet fixed distributor (1).
  • the inlet housing (7) and the filter element housing (12) in which the filter element(s) ( 1) are located are affixed to the rotating inlet header (3). In this case, the inlet housing (7) and filter element housing (12) are replaced with larger ones to hold more filter elements (11 ) in order to increase the installed filtration area.
  • FIG. 13 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the outlet vent (16) and depressurization port (20).
  • a rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2).
  • the outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4). In this case, the outlet housing (8) and filter element housing (12) are replaced with larger ones to hold more filter elements (11) in order to increase the installed filtration area.
  • FIG. 14 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15).
  • a rotating inlet header (3) with inlet ports (17) and oval port (21) is installed around the inlet fixed distributor (1).
  • the inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3).
  • Plugs (19) serve to block the flow to the inlet ports (17) so that some of the larger housing subassemblies (7,1 ,12), that were enlarged as shown in FIG. 12, can be removed to reduce the installed filtration area using the larger housings.
  • FIG. 15 Schematically shows the bottom view of the main outlet (1U) " tfie owfief fixed coyect f ⁇ ) wrtb.' the outlet distributor flow channel (6) and the outlet vent (16) and depre'ssurizatio ⁇ port (20).
  • a rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2).
  • the outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4).
  • Plugs (19) serve to block the flow to the outlet ports (18) so that some of the larger housing subassemblies (8,11,12) that were enlarged as shown in FIG. 13 can be removed to reduce the installed filtration area using the larger housings.
  • FIG. 16 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15).
  • a rotating inlet header (3) with inlet ports (17) and oval port (21) is installed around the inlet fixed distributor (1).
  • the inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3).
  • one housing subassembly (7,11,12) is shown to be normally in the stand-by mode. This is achieved by reducing the length of the inlet distributor flow channel (5).
  • FIG. 17 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the outlet vent (16) and depressurization port (20).
  • a rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2).
  • the outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4).
  • one housing subassembly (8,11,12) is shown to be normally in the stand-by mode. This is achieved by reducing the length of the outlet distributor flow channel (6).
  • FIG. 18 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the reverse-flow outlet (22).
  • a rotating inlet header (3) with inlet ports (17) is installed around the inlet fixed distributor (1 ).
  • the inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3).
  • FIG. 19 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the utlet distributor flow channel (6).
  • a rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2).
  • the outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4).
  • FIG. 20 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1 ) with the inlet distributor flow channel (5) and the reverse-flow outlet (22).
  • a rotating inlet header (3) with inlet ports (17) is installed around the inlet fixed distributor (1).
  • the inlet housing (7) * and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3).
  • a specific portion of the clean filtrate is allowed to flow in the reverse direction through the filter element (s) (11) for cleaning purposes.
  • the filtrate portion being used for cleaning, exits through the reverse-flow outlet (22).
  • FIG. 21 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6).
  • a rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2).
  • the outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4). In this reverse-flow case, a specific portion of the clean filtrate is allowed to flow from the outlet fixed collector (2), in the reverse direction through the filter element (s) (11) for cleaning purposes.
  • FIG. 22 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the reverse-flow inlet (23).
  • a rotating outlet header (4) with Outlet ports (18) is installed around the outlet fixed collector (2).
  • the outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4).
  • FIG. 23 Schematically shows the bottom view of the main outlet (1j ) * ttie oulIet " fi ed " co[lett ⁇ j , ,(2) with, the outlet distributor flow channel (6).
  • a rotating outlet header (4) with ⁇ ulfet ports (18) is installed around the outlet fixed collector (2).
  • the outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4).
  • a suitable liquid is allowed to flow from the reverse flow inlet (23) in the reverse direction through the filter element (s) ( 1 ) for cleaning purposes.
  • FIG. 24 Schematically shows the filter system with a main inlet (13) and a main outlet (14). Attached to the main inlet (13) and main outlet (14) is the combined rotating inlet and outlet headers (3,4) with inlet ports (17) and outlet ports (18), and the combined inlet fixed distributor and outlet fixed collector (1,2) with inlet distribution flow channel (5) and outlet distributor flow channel (6).
  • the above figures illustrate the simple design of the element filter housing (12), which is basically a cylinder with one small, or one large hole to hold multiple filter elements (11).
  • the invention covers similar designs where multiple holes for individual filter elements (11) may be provided in the element filter housing (12) to streamline the flow and minimize the residence time and its distribution.
  • the invention covers similar designs with multiple concentric circles just the same.
  • the above figures show the filter element (11 ) as a cartridge type filter element; the invention covers filter systems with differently shaped filter elements just the same. For example, a stack of filter discs could be used in every single element filter housing (12).
  • the rotatable filter assembly is rotated so that one housing subassembly (7,8,12) is isolated from the flowing product and in turn gets depressurized through the depressurization port (20). Then the housing subassembly (7,8,12) is either removed for remote servicing or is serviced on the filter; in either case the filter element(s) (1 ) would be replaced with clean one. All along, the product is still flowing.
  • the rotatable filter assembly is rotated further to the one and only bleeding and venting position of the filter, so that the newly serviced housing subassembly (7,8,12) can be filled with product by bleeding through the inlet bleeding port (15) and vented through the outlet vent (16). Then, the rotatable filter assembly is rotated further in order to return the newly serviced housing subassembly (7,8,12) into the filtration service. The rotation cycle would then be repeated for the service of the remaining housing subassemblies (7,8,12). Again, all along the complete rotation cycle, there is no interruption of product flow.
  • the rotatable filter assembly When a specific condition such as the differential pressure over the filter system indicates that the cleaning of the filter elements is required, the rotatable filter assembly is rotated so that one housing subassembly (7,8,12) is isolated from the flowing product on the inlet side only at the reverse-flow port (22). A part of the filtrate being, or another suitable liquid, under pressure flows from the outlet fixed collector or reverse flow inlet, in the reverse direction through the filter element(s) (11) and exits via the reverse-flow port (22). After an appropriate period of time and the cleaning completion, the rotatable filter assembly is rotated further in order to return the newly cleaned housing subassembly (7,8,12) into the filtration service. The rotation cycle would then be repeated for the cleaning of the remaining filter elements (11 ). All along the complete rotation cycle, there is no interruption of product flow.

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Abstract

The invention relates to a process and a filter system for continuous filtration of liquids, in particular viscous fluids such as molten polymers. In the process according to the invention, multiple filter housing subassemblies (12) are assembled around rotating inlet and outlet headers (3,4) which in turn are fitted to fixed inlet distributor (1) and outlet collector (2), forming a rotatable filter assembly that at the same time allows a uniform product flow to continuously pass through all of the installed filter housings during the normal filtration cycle, and the majority of the installed filter housings during the rotation cycle. In the rotation cycle when necessary, the rotatable filter assembly is rotated so that one housing subassembly is isolated from the flowing product and in turn gets removed or prepared for servicing and replacement of the filter element(s). After the service completion, the rotatable filter assembly is rotated further to the one and only bleeding and venting position so that the newly serviced housing subassembly can be filled with product by bleeding through the inlet bleeding port and vented through the outlet vent before the rotatable filter assembly is rotated further in order to return it to the filtration service.

Description

PROCESS AMD FILTER SYSTEM FOR CONTINUOUS FILTRATION OF LIQUIDS
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The invention relates to a process and a filter system for continuous filtration of liquids, in particular viscous fluids such as molten polymers. It also relates to a filter system to carry out such a process.
2. BACKGROUND OF THE INVENTION
The filtration of molten polymers is necessary while producing man-made fibers, film, etc. The production processes require continuous flow of clean molten polymer. Impurities, such as contaminants and gels, tend to cause fiber breakage or film ripping during the spinning and orientation phases.
Continuity and uniformity of flow are critical process conditions. Stagnation areas and creeping flows cause polymer degradation due to high residence time at elevated temperatures. Degradation products add impurities to the polymer stream being processed. These impurities have to be removed in order to avoid production problems mentioned earlier. Consequently, the residence time of a molten polymer in a filter system is a critical factor.
Currently, most of the filtration processes are carried out using the so-called screen changer for a small installed filtration area as shown in U.S. Patent No. 3,007,199 (Curtis), and systems that contain two filter housings and two diverter valves for a large installed filtration area as shown in U.S. Patent No. 3,833,121 (Singleton et al) and in U.S. Patent No. 3,727,767 (Itter et al)
While there exist many types of screen changers and other small area filters, there is a limited availability of large-filter-area polymer filter, most of which are similar in construction. In these type of filters, the molten polymer flows through the inlet diverter valve, then through one of the filter housings and out through the second outlet diverter valve. When the filter elements in the housing become exhausted, the flow gets diverted to the second housing, which has fresh filter elements. The exhausted filter housing is then removed, cleaned, returned with fresh filter elements, and put on stand-by mode until the second housing becomes exhausted.
The diverter valves regulate the flow at the inlet and at the outlet of the system. When switching from one filter housing to the second, the valve at the inlet is moved first, allowing a small portion of the flow to enter the fresh filter housing. The valve at the outlet side remains unchanged. A vent valve on the fresh filter housing is opened to allow the incoming product flow to fill the filter housing completely (venting or bleeding of the filter housing to come on-stream). When the fresh filter housing is completely filled with product, the vent valve is closed and the diverter valves at the inlet and at the outlet are moved simultaneously to force the complete product flow through the fresh filter housing, thus taking the first filter housing off-stream.
It may be noted, that because of the bleeding and venting phase, the feed portion used to fill the fresh filter housing sees, at an assumed bleed flow of ten percent of total flow, a residence time ten times that of the normal feed flow. As a consequence, the above described product degradation may occur.
Filter systems with two filter housings and two diverter valves have an installed filter area equal to twice the filter area that is on-stream. Normally at least three complete filter housings are needed for continuous operation: one housing on-line, one housing on stand-by and one housing undergoing external cleaning and replacing of filter elements.
The diverter valves define the most critical parts of these double filter systems. It is particularly difficult to design and manufacture such valves absolutely free of gaps, dead flow areas, and areas with reduced flow velocity. In the filtration of molten polymers, such gaps and areas with different flow characteristics may lead to product degradation with subsequent production problems as described earlier.
l In addition, it may be noted that in case of an error where an operator complete^ shifts $ iff1<Sr.ohe o the inlet or outlet diverter valve without the other, when the product i§ flowisigV&e syatenrwlll deafl- fiead the pump/extruder and may cause the activation of the safety device such as a rupture disk. Such systems are not inherently safe and do not normally have safety interlocks when provided with manual operation.
Also, filter systems with two filter housings and two diverter valves do not offer the flexibility to easily change the filtration area of the installed filters in case of production rate and/or filter rating change requirements. This would require a variety of housing sizes to accommodate a variety of production rates and filter ratings.
OBJECTS OF THE INVENTION
The primary object of the invention is to provide an apparatus and a process to continuously filter highly viscous fluids, in particular molten polymers and to overcome the disadvantages associated with the prior art.
Another object of the invention is to provide an apparatus and a process to narrow and minimize the residence time distribution of the flowing products.
Another object of the invention is to provide an apparatus and a process without the use of dedicated diverter valves.
Another object of the invention is to provide an apparatus and a process in which the entire available filtration area is used in the best way possible.
Another object of the invention is to provide an apparatus and a process in which the filter replacement would be achieved without flow interruption.
Another object of the invention is to provide an apparatus and a process in which only one bleeding and venting position is used.
Another object of the invention is to provide an apparatus and a process in which the filtration area may be changed without product flow interruption.
Another object of the invention is to provide an apparatus and a process in which the filtration area may be changed without changing the main apparatus assembly.
Another object of the invention is to provide an apparatus and a process with inherent safety of operation.
Another object of the invention is to provide an apparatus and a process in which the filter elements may be cleaned in place with the filtrate or another fluid reverse-flow.
SUMMARY OF THE INVENTION
The basis for the invention is the idea to have a filter system for highly viscous liquids, in particular molten polymers, that provides continuity, that offers a desired range of filter area on-stream, that eliminates the need for switch-over valves, that avoids prolonged residence times typical of bringing fresh filter area on-stream, that needs only one bleeding and venting position, and that offers inherently safe operation.
A process and a filter system according to the invention with the features of the listed claims ι neet the above requirements.
The invention defines a continuous filtration process. There is no interruption of operation foreseen whenever filter area gets exhausted. By rotating the filter assembly of the filter system, a small portion of the filter area is taken off-line, and then a fresh filter housing subassembly is introduced to the flow. During rotation, all but one of the multiple filter housings on-stream remain on-stream.
The invention includes a filter system with basically multiple filter housing subassemblies that are assembled and affixed around rotating inlet and outlet headers which in turn are fitted to fixed inlet and outlet collectors, forming a rotatable filter assembly that at the same time allows a uniform product flow to continuously pass through all of the installed filter housings during the normal filtration cycle, and the majority of the installed filter housings during the rotation cycle. In the rotation cycle, when necessary, the rotatable filter assembly is rotated so that one housing subassembly is isolated from the flowing product and in turn gets depressurized through the depressurization port and then is removed or prepared for servicing and replacement of the filter element(s). After the service completion, the rotatable filter assembly is rotated further to the one and only bleeding and venting position so that the newly serviced housing subassembly can be filled with product by bleeding through the unique inlet bleeding port and vented through the outlet vent before the rotatable filter assembly is rotated further in order to return it to the filtration service. The rotation cycle would then be repeated for the service of the remaining housing subassemblies. Provisions to decrease the installed filtration areas are made by removing one or more housing subassemblies and replacing them with plugs. Provisions to increase the installed filtration areas are made by removing one or more housing subassemblies and replacing them with larger ones.
The product flow enters the main inlet and then gets distributed, by the inlet distributor flow channel, over any desired number (In this case 8 ports are shown in the drawings, this can be changed to any desired number of ports with corresponding housings) of inlet ports. The flow then enters the filter inlet housing, which may have any desired type of opening, and then enters the filter element housings with one or more filter elements. The flow then enters the filter element(s) and then the outlet housing, which may have any desired type of opening, then enters the outlet port. The flow passing through the individual outlet ports is then collected in the outlet collector flow channel. The flow then exits the system through the main outlet.
The filter system according to the invention forces the product flow from its original flow path into the distributor serving multiple filter housings. The size and shape of the distributor, as well as the size and the number of filter housings can be scaled according to individual needs, putting no fundamental restrictions on the filter area that may be installed.
To change filter housing subassemblies or the filter element(s), the filtration process according to the invention lacks the need to install specific diverter valves. The flow distribution over the multiple housings is affected by the fixed iniet distributor and outlet collector, which need not to be changed during any phase of operation. The particular advantage of the invention for the changing lof exhausted • filte a.reg.is* in 'the* circumstances that only a part of the filter arpa on line at any given 'time Is being replaced by fresh filter area. During normal operation, multiple filter housing subassemblies, say for example ten are on-stream. All these housings see, on the average ten percent of the incoming flow. Bleeding takes place for only one fresh filter housing subassembly at any given time. Assuming ten percent of the flow is used for bleeding, then the bleeding flow portion takes only so much time, as is the typical residence time for the product in the filter during normal operation. After bleeding, one filter housing subassembly is turned off-stream; the just bled and vented housing subassembly is turned on-stream.
A provision to have one filter housing subassembly on stand-by mode is here considered. This allows the simultaneous removal and introduction of filter housing subassemblies without any change to the size of the installed area. This provision is realized by altering the design of the inlet distributor and outlet collector.
Compared to the known filter operation processes as referred to in the prior art, the invention offers the possibility to replace the exhausted filter area one fraction by fraction at a time.
Preferably a filter system according to the invention is provided in such a way that the system is self- cleaning by means of a reverse flow of clean filtrate or another suitable fluid through the exhausted filter area. The changing of exhausted filter elements can be avoided by such a reverse flow of clean filtrate or another suitable fluid.
The critical design area of the filter system according to the invention is the sealing of the rotating inlet and outlet headers to the inlet fixed distributor and outlet fixed collector respectively. Given the specific process conditions, an appropriate seal would be provided to meet such conditions. The seals may be made of a variety of elastomeric materials, or a special wear-resistant coating may be applied to a metal surface to affect a metal to metal sealing.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects, features and advantages of the invention will become more apparent from the following brief description of the drawings:
FIG 1. Front view of filter assembly according to invention.
FIG 2. Top view of inlet assembly. Here the outlet assembly is not shown.
FIG 3. Bottom view of outlet assembly. Here the inlet assembly is not shown.
FIG 4. Top view of inlet assembly where filter housing subassemblies are rotated so that a filter housing subassembly is isolated for service. Here the outlet assembly is not shown.
FIG 5. Top view of inlet assembly where filter housing subassemblies are rotated further so that a filter housing subassembly is in the feed bleed position. Here the outlet assembly is not shown.
FIG 6. Top view of inlet assembly where filter housing subassembljes are rotated further so that the newly serviced filter housing subassembly is returned the to filtration service. Here the outlet assembly is not shown.
FIG 7. Bottom view of outlet assembly where filter housing subassemblies are rotated so that a filter housing subassembly is isolated for service. Here the iniet assembly is not shown.
FIG 8. Bottom view of outlet assembly where filter housing subassemblies are rotated further so that a filter housing subassembly is in the vent position. Here the inlet assembly is not shown. IG 9. Bottom view of outlet assembly where filter housing subassemblies are rotated further so that the newly serviced filter housing subassembly is returned the to filtration service. Here the inlet assembly is not shown. IG 10. Top view of inlet assembly where some of the filter housing subassemblies are removed to reduce the installed filtration area. . IG 11. Bottom view of outlet assembly where some of the filter housing subassemblies are removed to reduce the installed filtration area. IG 12. Top view of iniet assembly where the filter housing subassemblies are replaced with larger ones to increase the installed filtration area. IG 13. Bottom view of outlet assembly where the filter housing subassemblies are replaced with larger ones to increase the installed filtration area. IG 14. Top view of inlet assembly where some of the filter housing subassemblies, with larger installed filtration area, are removed to reduce the installed filtration area. IG 15. Bottom view of outlet assembly where some of the filter housing subassemblies, with larger installed filtration area, are removed to reduce the installed filtration area. IG 16. Top view of inlet assembly where one housing subassembly is normally on stand-by mode. IG 17. Bottom view of outlet assembly where one housing subassembly is normally on stand-by ' mode. IG 18. Top view of inlet assembly with the reverse flow outlet port. Here the outlet assembly is not shown. Bottom view of outlet assembly for the clean, filtrate reverse .flow case! .tferø .the irrfet assembly is not shown. Top view of inlet assembly in the reverse flow mode. Here the outlet assembly is not shown. Bottom view of outlet assembly in the reverse flow mode. Here the inlet assembly is not shown. Bottom view of outlet assembly with the reverse flow inlet for another liquid reverse flow case. Here the inlet assembly is not shown. Bottom view of outlet assembly for another liquid reverse flow mode. Here the inlet assembly is not shown. Front view of the combined rotating inlet and outlet headers, and the combined inlet fixed distributor and outlet fixed collector.
SPECIFIC DESCRIPTION
By its nature, the invention is subject to many design variations and details. The following figures are to be considered schematic illustrations of the concepts and should not be used as limiting design factors:
FIG. 1 Schematically shows the filter system according to the invention with a main inlet (13) and a main outlet (14). Attached to the main inlet (13) is an inlet fixed distributor (1) with an inlet distribution flow channel (5). Attached to the main outlet (14) is an outlet fixed collector (2) with an outlet distributor flow channel (6). A rotating inlet header (3) with inlet ports (17) is installed around the inlet fixed distributor (1). A rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2). Filter housing subassemblies; comprising of an inlet housing (7) with a housing inlet channel (9), a filter element housing (12) in which the filter element(s) (11) are located, and an outlet housing (8) with a housing outlet channel (10), are affixed to the rotating inlet header (3) and the rotating outlet header (4). The filter housing subassemblies along with rotating inlet header (3) and the rotating outlet header (4) form one whole rotatable filter assembly.
FIG. 2 Schematically shows the top view of the main iniet (13), the inlet fixed distributor (1) with the- inlet distributor flow channel (5) and the inlet bleed (15). A rotating inlet header (3) with inlet ports (17) and oval port (21) is installed around the inlet fixed distributor (1). The inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3).
FIG. 3 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the outlet vent (16) and depressurization port (20). A rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2). The outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4).
FIG. 4 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15). A rotating inlet header (3) with inlet ports (17) and oval port (21 ) is installed around the inlet fixed distributor (1 ). In this view, the rotating inlet header (3) is rotated so that one housing subassembly (7,11,12) is depressurized and isolated for service. The inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3).
FIG. 5 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15). A rotating inlet header (3) with inlet ports (17) is installed around the inlet fixed distributor (1 ). In this view, the rotating inlet header (3) is rotated further so that the same housing subassembly (7,1 ,12) that was isolated as shown in FIG. 4 is in the bleed position. The inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3).
FIG. 6 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15). A rotating inlet header (3) with inlet ports (17) is installed around the inlet fixed distributor (1). In this view, the rotating inlet header (3) is rotated further so that the same housing subassembly (7,11,12) that was bled as shown in FIG. 5 is returned to the filtration service. The inlet housing (7) and the filter element housing (12) in which the filter element(s) (11 ) are located are affixed to the rotating inlet header (3).
FIG. 7 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the outlet vent (16) and depressurization port (20). A rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2). In this view, the rotating inlet header (3) is rotated so that one housing subassembly (8,11,12) is depressurized and isolated for service. The outlet housing (8) and the filter element housing (12) in which the filter element(s) (11 ) are located are affixed to the rotating outlet header (4). FIG, 8 Schematically shows the bottom view of the main outlet (1'4)' tl otitlefrfijed coite*ctor.(2) wth- the outlet distributor flow channel (6) and the putlet vent (16) and depre'ssύrization port (20). A rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2). In this view, the rotating outlet header (4) is rotated further so that the same housing subassembly (8,11,12) that was isolated as shown in FIG. 4 and 7 is in the vent position. The outlet housing (8) and the filter element housing (12) in which the filter element(s) (11 ) are located are affixed to the rotating outlet header (4).
FIG. 9 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the outlet vent ( 6) and depressurization port (20). A rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2). In this view, the rotating- outlet header (4) is rotated further so that the same housing subassembly (8,11,12) that was isolated as shown in FIG. 5 and 8 is in the bleed position. The outlet housing (8) and the filter element housing (12) in which the filter element(s) (11 ) are located are affixed to the rotating outlet header (4).
FIG. 10 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15). A rotating inlet header (3) with inlet ports (17) and oval port (21) is installed around the inlet fixed distributor (1). The inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3). Plugs ( 9) serve to block the flow to the inlet ports (17) so that some of the housing subassemblies (7,11,12) can be removed to reduce the installed filtration area.
FIG. 11 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the outlet vent (16) and depressurization port (20). A rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2). The outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4). Plugs (19) serve to block the flow to the outlet ports (18) so that some of the housing subassemblies (8,11,12) can be removed to reduce the installed filtration area.
FIG. 12 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15). A rotating iniet header (3) with inlet ports (17) and oval port (21) is installed around the inlet fixed distributor (1). The inlet housing (7) and the filter element housing (12) in which the filter element(s) ( 1) are located are affixed to the rotating inlet header (3). In this case, the inlet housing (7) and filter element housing (12) are replaced with larger ones to hold more filter elements (11 ) in order to increase the installed filtration area.
FIG. 13 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the outlet vent (16) and depressurization port (20). A rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2). The outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4). In this case, the outlet housing (8) and filter element housing (12) are replaced with larger ones to hold more filter elements (11) in order to increase the installed filtration area.
FIG. 14 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15). A rotating inlet header (3) with inlet ports (17) and oval port (21) is installed around the inlet fixed distributor (1). The inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3). Plugs (19) serve to block the flow to the inlet ports (17) so that some of the larger housing subassemblies (7,1 ,12), that were enlarged as shown in FIG. 12, can be removed to reduce the installed filtration area using the larger housings. FIG. 15 Schematically shows the bottom view of the main outlet (1U)" tfie owfief fixed coyect f^) wrtb.' the outlet distributor flow channel (6) and the outlet vent (16) and depre'ssurizatioή port (20). A rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2). The outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4). Plugs (19) serve to block the flow to the outlet ports (18) so that some of the larger housing subassemblies (8,11,12) that were enlarged as shown in FIG. 13 can be removed to reduce the installed filtration area using the larger housings.
FIG. 16 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the inlet bleed (15). A rotating inlet header (3) with inlet ports (17) and oval port (21) is installed around the inlet fixed distributor (1). The inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3). In this view, one housing subassembly (7,11,12) is shown to be normally in the stand-by mode. This is achieved by reducing the length of the inlet distributor flow channel (5).
FIG. 17 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the outlet vent (16) and depressurization port (20). A rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2). The outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4). In this view, one housing subassembly (8,11,12) is shown to be normally in the stand-by mode. This is achieved by reducing the length of the outlet distributor flow channel (6).
FIG. 18 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1) with the inlet distributor flow channel (5) and the reverse-flow outlet (22). A rotating inlet header (3) with inlet ports (17) is installed around the inlet fixed distributor (1 ). The inlet housing (7) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3).
FIG. 19 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the utlet distributor flow channel (6). A rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2). The outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4).
FIG. 20 Schematically shows the top view of the main inlet (13), the inlet fixed distributor (1 ) with the inlet distributor flow channel (5) and the reverse-flow outlet (22). A rotating inlet header (3) with inlet ports (17) is installed around the inlet fixed distributor (1). The inlet housing (7)*and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating inlet header (3). In this reverse-flow case, a specific portion of the clean filtrate is allowed to flow in the reverse direction through the filter element (s) (11) for cleaning purposes. The filtrate portion, being used for cleaning, exits through the reverse-flow outlet (22).
FIG. 21 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6). A rotating outlet header (4) with outlet ports (18) is installed around the outlet fixed collector (2). The outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4). In this reverse-flow case, a specific portion of the clean filtrate is allowed to flow from the outlet fixed collector (2), in the reverse direction through the filter element (s) (11) for cleaning purposes.
FIG. 22 Schematically shows the bottom view of the main outlet (14), the outlet fixed collector (2) with the outlet distributor flow channel (6) and the reverse-flow inlet (23). A rotating outlet header (4) with Outlet ports (18) is installed around the outlet fixed collector (2). The outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4). FIG. 23 Schematically shows the bottom view of the main outlet (1j )* ttie oulIet"fi ed"co[lettρj,,(2) with, the outlet distributor flow channel (6). A rotating outlet header (4) with δulfet ports (18) is installed around the outlet fixed collector (2). The outlet housing (8) and the filter element housing (12) in which the filter element(s) (11) are located are affixed to the rotating outlet header (4). In this reverse-flow case, a suitable liquid is allowed to flow from the reverse flow inlet (23) in the reverse direction through the filter element (s) ( 1 ) for cleaning purposes.
FIG. 24 Schematically shows the filter system with a main inlet (13) and a main outlet (14). Attached to the main inlet (13) and main outlet (14) is the combined rotating inlet and outlet headers (3,4) with inlet ports (17) and outlet ports (18), and the combined inlet fixed distributor and outlet fixed collector (1,2) with inlet distribution flow channel (5) and outlet distributor flow channel (6).
The above figures illustrate the simple design of the element filter housing (12), which is basically a cylinder with one small, or one large hole to hold multiple filter elements (11). The invention covers similar designs where multiple holes for individual filter elements (11) may be provided in the element filter housing (12) to streamline the flow and minimize the residence time and its distribution. The invention covers similar designs with multiple concentric circles just the same. Also, the above figures show the filter element (11 ) as a cartridge type filter element; the invention covers filter systems with differently shaped filter elements just the same. For example, a stack of filter discs could be used in every single element filter housing (12).
To further illustrate the procedure to renew the filter area, the procedure is as follows while referring to figures 1 through 10:
When a specific condition such as the differential pressure over the filter system indicates that a change of filter area is required, the rotatable filter assembly is rotated so that one housing subassembly (7,8,12) is isolated from the flowing product and in turn gets depressurized through the depressurization port (20). Then the housing subassembly (7,8,12) is either removed for remote servicing or is serviced on the filter; in either case the filter element(s) (1 ) would be replaced with clean one. All along, the product is still flowing. After the service completion, the rotatable filter assembly is rotated further to the one and only bleeding and venting position of the filter, so that the newly serviced housing subassembly (7,8,12) can be filled with product by bleeding through the inlet bleeding port (15) and vented through the outlet vent (16). Then, the rotatable filter assembly is rotated further in order to return the newly serviced housing subassembly (7,8,12) into the filtration service. The rotation cycle would then be repeated for the service of the remaining housing subassemblies (7,8,12). Again, all along the complete rotation cycle, there is no interruption of product flow.
In the case of the reverse flow cleaning, the procedure is as follows while referring to figures 18 through 23:
When a specific condition such as the differential pressure over the filter system indicates that the cleaning of the filter elements is required, the rotatable filter assembly is rotated so that one housing subassembly (7,8,12) is isolated from the flowing product on the inlet side only at the reverse-flow port (22). A part of the filtrate being, or another suitable liquid, under pressure flows from the outlet fixed collector or reverse flow inlet, in the reverse direction through the filter element(s) (11) and exits via the reverse-flow port (22). After an appropriate period of time and the cleaning completion, the rotatable filter assembly is rotated further in order to return the newly cleaned housing subassembly (7,8,12) into the filtration service. The rotation cycle would then be repeated for the cleaning of the remaining filter elements (11 ). All along the complete rotation cycle, there is no interruption of product flow.

Claims

CLAIMSWhile I have illustrated and described specific embodiment of my invention, it should be understood that this is for illustrative purposes only and that various modifications, alterations and changes may be made within the contemplation of my invention and within the scope of the following claims:I claim:
1. Process to continuously filter liquids, in particular viscous fluids such as molten polymers, by means of multiple filter subassemblies, in which one or multiple filter elements are installed, that are attached and distributed around rotating headers, which may be rotated out and into the product stream in such a way that the product stream continuously flows through the remaining filter subassemblies.
2. Process according to claim 1, characterized by rotating headers, whose center is the rotational axis.
3. Process according to claim 1, characterized by rotating the filter assemblies when the differential pressure over the filter element (s) reaches a pre-set value.
4. Process, according to claim 1 or 2, characterized by replacing the dirty filter element being rotated out of the product stream with a fresh filter element at different times.
5. Process according to claim 1 or 2, characterized by replacing the dirty filter element being rotated out of the product stream with a fresh filter element simultaneously at the same time.
6. Filter system for continuous filtration of liquids in the process according to claim 1, including:
• A main product inlet into which, the product enters the system.
• An inlet fixed distributor in which the flow is distributed over the inlet ports.
• A rotating inlet header to which the housing subassemblies are attached. The rotating inlet header includes inlet ports through which the product enters the inlet housing.
• A housing subassembly comprising of: An inlet housing with an inlet channel through which the product enters the filter element housing, a filter element housing with one or multiple filter elements, an outlet housing with an outlet channel out of which the product exists the housing.
• A rotating outlet header to which the housing subassemblies are attached. The rotating outlet header includes outlet ports out of which the product exits to the outlet collector.
• An outlet fixed collector in which the flow is collected from the outlet ports.
• A main product outlet out of which, the filtered product exits the system.
7. Filter system according to claim 5, characterized by an inlet distributor flow channel and an outlet collector flow channel, which are flexible in size and shape and that can be extended over an angle of up to 360 degree and with their angular opened sides facing the rotating headers and their normal openings facing the main inlet and outlet.
8. Filter system according to claim 5, characterized by the inlet distributor and the outlet collector sealed to the rotating headers with a variety of elastomeric material seals or with metal- coated to metal-coated seal.
9. Filter system according to claim 5, 6 or 7, characterized by that the outlet collector might cover one filter subassembly more than the inlet distributor.
10. Filter system according to claim 5, 6 or 7, characterized by the outlet collector with a depressurization port.
11. Filter system according to claim 5, 6 or 7, characterized by the outlet collector with an outlet vent.
12. Filter system according to claim 5, 6 or 7, characterized by the inlet distributor and the inlet header with a matching bleed position.
13. Filter system according to claim 9 or 10, characterized by the rotation of the headers providing two through-flow positions, namely
• All filter subassemblies connected to the inlet distributor are also connected to the outlet collector.
• All but one of the filter subassemblies connected to the inlet distributor and outlet collector, whereas one of the filter subassemblies is connected to the depressurization port.
• All but one of the filter subassemblies connected to the inlet distributor and outlet collector, whereas one of the filter subassemblies is connected to the outlet vent and inlet bleed.
14. Filter system according to claim 5, 6 or 7, characterized by that one or more of the inlet ports and corresponding outlet ports might be plugged so that one or more of the housing subassemblies are removed.
15. Filter system according to claim 5, 6 or 7, characterized by that one or more, up to all of the housinπ subassemblies may be replaced with a larger ones to accommodate an increase of filtration area.
16. Filter s stem according to claim 5, 6 or 7, characterized by that the filter element might be in any form or shape.
17. Filter system according to claim 5, 6 or 7, characterized by that the system is self-cleaning by means of a reverse flow of clean filtrate through the exhausted filter area.
18. Filter system according to claim 5, 6 or 7, characterized by that the inlet and outlet fixed headers may be combined into one entity, and by that the inlet distributor and outlet collector may be combined into one entity.
19. Proces for continuously filter liquids substantially as herein described, particularly with reference to the accompanying drawings.
20. Filter system for continuous filtration liquids, in particular viscous fluids such as molten polymers, substantially as herein described.
PCT/EP2002/001502 2001-02-21 2002-02-13 Process and filter system for continuous filtration of liquids WO2002066228A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP02722073A EP1361948A1 (en) 2001-02-21 2002-02-13 Process and filter system for continuous filtration of liquids

Applications Claiming Priority (2)

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LB623901 2001-02-21
LB6239 2001-02-21

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WO2002066228A1 true WO2002066228A1 (en) 2002-08-29

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ITPD20090014A1 (en) * 2009-01-26 2010-07-27 Luciano Valotto SELF-CLEANING MULTI-FILTER-MIX MODULE FOR MULTIPLE STATION WITH RADIAL SEAL ON ROTARY MANIFOLD, WITH POWER AND OUTPUT ON CENTRAL SPINDLE
CN102657974A (en) * 2012-05-25 2012-09-12 济南佐田惠环保工程有限公司 Turntable structure of ultrathin overlaid filtering layer vertical filter press
CN104722128A (en) * 2015-03-05 2015-06-24 厦门建霖工业有限公司 Easy-to-exchange multi-interlayer filter element
JP2016523736A (en) * 2013-05-10 2016-08-12 グノイス ゲゼルシャフト ミット ベシュレンクテル ハフツングＧｎｅｕｓｓ ＧｍｂＨ How to drive a screen wheel filter
IT201700030694A1 (en) * 2017-03-21 2018-09-21 Luciano Valotto Self-cleaning filter unit with multiple filtering sections with different degrees of cleaning
CN108568150A (en) * 2017-03-14 2018-09-25 天津巨龙暖通设备开发有限公司 Filter device before a kind of steam heating pipe water inlet

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CN105396353B (en) * 2015-12-18 2017-10-20 浙江宇丰机械有限公司 High-viscosity material full-automatic back washing coarse filtration system
CN108939680B (en) * 2018-08-13 2021-07-30 东阳市特意新材料科技有限公司 Industrial sewage filtering device
CN113648715B (en) * 2021-10-20 2022-02-11 品孚罗特过滤设备（北京）有限公司 Continuous filtering multi-cavity alternate offline composite filtering device
CN115287770A (en) * 2022-06-14 2022-11-04 宁夏泰和芳纶纤维有限责任公司 Para-aramid spinning solution filter
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Cited By (7)

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Publication number Priority date Publication date Assignee Title
ITPD20090014A1 (en) * 2009-01-26 2010-07-27 Luciano Valotto SELF-CLEANING MULTI-FILTER-MIX MODULE FOR MULTIPLE STATION WITH RADIAL SEAL ON ROTARY MANIFOLD, WITH POWER AND OUTPUT ON CENTRAL SPINDLE
CN102657974A (en) * 2012-05-25 2012-09-12 济南佐田惠环保工程有限公司 Turntable structure of ultrathin overlaid filtering layer vertical filter press
CN102657974B (en) * 2012-05-25 2014-07-09 济南佐田惠环保工程有限公司 Turntable structure of ultrathin overlaid filtering layer vertical filter press
JP2016523736A (en) * 2013-05-10 2016-08-12 グノイス ゲゼルシャフト ミット ベシュレンクテル ハフツングＧｎｅｕｓｓ ＧｍｂＨ How to drive a screen wheel filter
CN104722128A (en) * 2015-03-05 2015-06-24 厦门建霖工业有限公司 Easy-to-exchange multi-interlayer filter element
CN108568150A (en) * 2017-03-14 2018-09-25 天津巨龙暖通设备开发有限公司 Filter device before a kind of steam heating pipe water inlet
IT201700030694A1 (en) * 2017-03-21 2018-09-21 Luciano Valotto Self-cleaning filter unit with multiple filtering sections with different degrees of cleaning

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