US2910841A - Evaporator for freezer mechanisms - Google Patents

Description

Nov. 3, 1959 L. E. BRANcHFLowER 2,910,841

EVAPORATOR FOR FREEZER MECHANISMS 5 Sheets-Sheet 1 Original Filed Feb. 8, 1951 INVENTOR.

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7 c l|ll a [.y/e E. Erano/flo wer Nov. 3, 1959 L. E. BRANCHFLOWER 2,910,841

EVAPORATOR FOR FREEZER MECHANISMS Original Filed Feb. 8. 1951 5 Sheets-Sheet 2 (2 y/e E. Branc/)flower ATTORNEY Nov. 3, 1959 L. E. BRANcHFLowER 2,910,841

EvAPoRAToR FOR FREEZER MEcHANsMs 5 Sheets-Sheet 5' Original Filed Feb. 8. 195i JNVENTOR. gy/e f. rancf/ower ATTORNEY Nov. 3, 1959 E. BRANcHFLowER 2,910,841

EVAPORATOR FOR FREEZER MECHANISMS 5 Sheets-Sheet 4 Original Filed Feb. 8. 1951 l Il lilll l l INVENTOR. y/e E. Bran B1. M f

eg f/o yer TTO/VEY Nov. 3, 1959 L. E. BRANcHFLowER 2,910,841

EVAPORATOR FOR F'RE'EZERv MECHANISMS 5 Sheets-Sheet 5 Original Filed Feb. 8, 1951 JNVENToR. Ly/e E. rdncf/ower BY v W X72??? United States Patent Ofice EVAPORATOR FOR FREEZER MECHANISMS Lyle E. Branchllower, Seattle, Wash.

Original application February 8, 1951, Serial No. 210,030. Divided and this application August 3, 1954, Serial No. 447,576

4 Claims. (Cl. 62-347) The present invention relates to ice making machines and the art thereof and is a divisional application of my co-pending application, Serial No. 210,030, led in the United States Patent Office on February 8, 1951, now Patent No. 2,735,275.

While devices of my invention herein are useful in vertical or horizontal ice makers, the invention of the present invention has its greatest utility in connection with ice forming on a horizontal surface and thus the invention is defined and described in association therewith.

The present invention relates to devices and processes for removal of ice having a temperature in the order of 32 F. and removing the ice in chip or particle form.

The prior art has recognized the problem of obtaining velocity to the refrigerant over the heat transfer surface to increase the heat transfer, to prevent the formation of gas pockets, and to reduce the accumulation of oil on the heat transfer surfaces. However, all of the prior art devices have the defect that velocity is attained by a loss of head and by a single pass of the refrigerant across the heat transfer surface. In these devices the velocity must be controlled by the rate of evaporation of the refrigerant or much wet refrigerant must be returned to the compression cycle. Further, such devices do not provide for efllcient separation of the gas from the liquid. Separation must occur in the machine which means that some of the heat transfer surface must be contacted by gas only and not liquid refrigerant. This means a low rate of heat transfer for these gas contacted areas.

An object of the present invention is the provision of La gas separator and liquid return for the refrigerant.

Another object is the provision of means for cycling liquid refrigerant across the heat transfer surfaces without the passing of such refrigerant to the compression unit.

Another object is the provision of refrigerant cycling means to obtain a high refrigerant velocity across the heat transfer surfaces, and which means operates as a combined thermosiphon and gas pump.

A further object is the provision of a gas separation space outside of the refrigerant evaporator.

Exterior of and concentric of the sleeve on which ice is formed is an annular refrigerant chamber, or evaporator chamber, which is flooded with a liquid refrigerant. The chamber is divided by an annular baille into two annular spaces that are in communication at the top and bottom of the spaces. The liquid level is maintained at or near the top of the baille. Liquid and gas will rise in the inner space and liquid alone flows downward in the outer space. Gas and entrained liquid are carried out of the top of the annular space to a gas separator from which the liquid returns to the outer annular space and the gas goes to a compressor.

The incoming refrigerant is expanded before reaching the evaporator and placed in heat exchange relationship with the incoming high pressure refrigerant to precool the refrigerant.

Other objects and advantages of my invention will become apparent as the description of the same proceeds Patented Nov. 3, 1959 and the invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming a part of the specification with the understanding, however, that the invention is not to be limited to the exact details of construction shown and described since obvious modifications will occur to a person skilled in the art.

Figure l is a perspective view of an assembled machine with parts thereof broken away of a device embodying my invention;

Fig. 2 is a sectional elevation view on the diameter of the machine;

Fig. 3 is a plan view of the device shown in Fig. 1;

Fig. 4 is a transverse sectional plan view on the line 4 4 of Fig. 2;

Fig. 5 is a transverse sectional plan view on the line 5-5 of Fig. 2;

Fig. 6 is a plan View of the water feed ring.

Fig. 7 is an enlarged view of a portion of the ring shown in Fig. 6;

Fig. 8 is a section on the line 8 8 of Fig. 7.

Fig, 9 is a detail view in perspective of two of the ice sweeps;

Fig. 10 is a detail View in perspective of a portion of the doctor blade and guard;

Fig. 11 is a detail view in perspective of the top edge scraper;

Fig. 12 is a detail view in perspective of the bottom edge scraper and the water trough guard.

In the accompanying drawings, there is shown in Figure 1 a perspective view of an assembled flake ice machine. Parts of the machine are shown broken away for clarity of understanding. In this view ther is shown the ice making machine mounted on the top of an ice storage bin 2 (shown in part only). The machine has as its principal parts a refrigerant precooler 3, a gas separation chamber 4, an annular evaporator 5, a base ring assembly 6, a top ring assembly 7, and a rotor assembly 8.

Evaporator The evaporator is composed of an upright inner cylindrical shell 10 upon the inner, or ice making surface 11, on which is formed the thin sheet of ice to be removed therefrom in the form of small flakes; an outer shell 12 concentric of the inner shell and spaced outwardly therefrom; a top end closure annulus 13; a bottom end closure annulus 14; and between said shells an annular circulation baille 15 that extends circumferentially and longitudinally of the annular evaporation chamber formed by said shells and end annuli, or rings, but is spaced from the ends and shells. The present evaporator is to be operated in a ilooded condition with the refrigerant 16, preferably ammonia, ilooding over the top of the circulation baflle 15. Refrigerant is delivered from the pre-cooler 3 to the interior of the evaporator by way of the separator 4 thru a refrigerant inlet 17 (see Figs. 2 and 4) formed in the lower part of the separator 4 and refrigerant is removed from the evaporator to the separator 4 thru a refrigerant outlet opening 18 formed in the outer shell 12 adjacent-the top edge thereof. An inlet opening 20 is provided in the shell 12 for the return of liquid refrigerant from the separator 4. In actual use the outside of the outer shell 12 is covered with insulation which has not been shown in the drawings as such would only confuse the showing thereof. Also, in actual use, the pre-cooler and the separator would be covered with insulation.

Top and bottom rings The evaporator is set on the base ring 6 that carries on its interior and circumferentially thereof a water trough that opens upwardly and is formed by the outer trough and base ring `21, the inner trough ring 22 spaced inwardly from the outer ring, and the trough bottom annulus 23. The inner ring 22 has a slightly smaller diameter than the inner shell 10 of the evaporator. Water collects in the trough from the excess water running off the lower edge of the ice making surface 11 and from overflow from the water feed overflow chamber. Water in the trough is drained therefrom thru trough drain opening 24 formed in the base ring 21. Spider arms 25, 26 are secured radially of the rings 21, 22 to support at the axis of the evaporator a radial-thrust bearing 27.

Set on the evaporator is a top ring assembly 7 that is composed of the cylindrical ring 28 that has spider arms 29, 30, 31 (see Fig. 3) secured radially thereof to support at the axis of the evaporator a radial-thrust bearing 32 (see Fig. 2). The annular opening thru the top ring may be closed by fixed annular closure plate 33 and removable ones similar to the fixed ones but not shown in the drawings.

Rotor assembly There is only one moving assembly in the machine. This rotor assembly 8 is driven by a gear head motor 40 that is mounted on the fixed closure plate 33 in the top ring assembly 7. This motor drives a pinion 41 that meshes with a gear 42 secured to and coaxial of a composite shaft having a top section 43 to which the gear 42 is secured, and a bottom section 44. In the present disclosure, in plan view, the shaft has counter clock rotation. Secured to the bottom section of the shaft are upper and lower shaft arms 45, 46. These arms carry a sweep rail 47 that is rectangular in cross-section, that extends from the top edge to the lower edge of the evaporator and that is placed close to the ice making surface 11 of the evaporator with its side opposed to such surface.

Secured to the side of the rail in opposition to the ice freezing surface are a series of sweeps 48. Each sweep (Figs. 4 and 9) is somewhat in the form of a flat plate having one edge secured to a sweep base 48A fastened to the side of the rail 47 opposed to the ice surface 11. Each sweep extends away from its base and the rail, and past the trailing edge of the rail. The trailing portion 49 of the sweep may be said to have rake with respect to the rail 47. This trailing, or rake, portion has a sharp edge 50 in opposition to the freezing surface. This edge is obtained by beveling the top of the rake to leave or form the edge in the plane of the lower face of the rake. The sweep and this rake edge are at a slight angle, about 4 to to a plane normal to the axis of the freezing surface. In a machine in which the radius of the freezing surface is about two feet or more, the rake edge 50 may lie in a plane, but in smaller machines the edge would approach the form of a portion of a cylindrical helix whose diameter is that of the diameter of the freezing surface.

As a specific example, if the radius of the freezing surface is twenty inches, the rake edge 50 is two and onefourth inches long, lies in a plane, and is curved to a radius of twenty inches. The trailing end of the rake edge is seven-thirtyseconds of an inch below the leading end of the edge. This slope of the rake edge sweeps the ice from the ice surface 11. The sweeps are spaced about one and one-half inches apart. All or most of the rake portion of the sweep trails the sweep rail. The sweeps may be secured to the rail by welding, bolting, or keying.

The angle that the rake edge makes with a plane normal to the axis of the evaporator may be considered to be the angle of lead, or the lead, as in a screw thread. This angle, or lead, is critical as too great a lead will cause the ice to powder and too small a lead will not effect satisfactory ice removal as to quantity. Under proper shaping and location of the rake edge, and with Dry Ice about one-eighth to one sixteenth inches thick, the ice removal at each passage of the sweeps is in the order of ninety-eight percent complete. Also, with this shaping of the rake and its edge, all the forces exerted on the ice by the sweep are parallel, or tangential, to the surface of the ice, except for such forces as may result at the forward end of the rake edge where it enters the ice. There is no force component where sweep and ice contact that is normal to the ice freezing surface. Such a normal force causes the ice to powder along the rake edge with the result that forces are not transmitted thru the ice for any distance suiiicient to loosen the ice between adjacent sweeps. This results in such or most of the ice being left on the freezing surface until a very thick layer is built up, as after several passages of the sweeps.

Frost builds up on the end annuli 13, 14 and will extend inwardly beyond the ice making surface 11. This frost is scraped back llush with the surface 11 by upper and lower Scrapers 51 and 52 (Figs. ll and 12) which are secured by arms to the upper and lower end, respectively, of the sweep rail 47, and which Scrapers have their scraping edges adjacent and overhanging the ends of the freezing surface.

Also, carried at the lower end of the sweep rail 47 is a trough guard S3 (Fig. l2) that prevents ice falling from the sweeps from entering the trough formed in the base ring assembly 6. Any ice hitting the guard will be deflected inside of the inner trough ring 22 (Fig. 2) and will fall into the bin 2. The sweep rail 47 carries outboard of its trailing edge a rubber doctor blade 54 (Fig. 10) and blade guard 55 that extend from the top to the bottom edge of the evaporator. This doctor blade and guard prevent scattering of the ice coming from the sweeps, and the blade removes loose ice that might adhere to the ice freezing face 11. The doctor blade and guard are secured to the sweep rail by bent straps 56.

Water system Water is delivered to the freezing surface 11 by a water recycle pipe 60 (Fig. 2) that empties into the upper end of the hollow top section 43 of the composite shaft. The lower end of this top section is closed by a plug 61 which has extending therethrough a short length of overflow pipe 62 whose upper end is somewhat above the plug. Water collecting above the plug is carried away thru nozzle ring pipes 63, 64 (Fig. 4) to a nozzle ring 65 that is concentric of the evaporator, adjacent the upper edge of the freezing surface, and carried on nozzle ring arms 66 secured to and radially of the upper end of the bottom section 44 of the shaft. The nozzle ring 65 is hollow, square in cross section and has around its lower outer edge a series of orifices 67, or nozzles, that are shaped to direct streams of water outwardly, downwardly and circumferentially in the direction of rotation and against the ice forming surface 11. This directing of the water against and circumferentially of the ice forming surface spreads the water over the surface and prevents its channeling. It, also, gives immediate coverage with water at the top of the freezing surface. The nozzle ring is segmental for about 270 from immediately behind the doctor blade 54 and its guard 55. In this relationship, the doctor blade and guard prevent water from reaching the falling ice. The ninety degrees of the nozzle ring that is open allows the ice time in which to dry and to be removed. The water delivered thru the ring is maintained constant by holding a fixed pressure, or head, on the ring. This is accomplished by the use of the overflow pipe 62 and by maintaining during operation of the machine a flow thru the overflow to compensate for variations in the amount of water delivered to the top section 43. The overflow water passes thru the overflow pipe 62 and into the top of the bottom section 44 where it is stopped by a plug 68 (Fig. 2). A drain pipe 69 leads from above the plug 68 to the water collecting trough in the base ring assembly 6. This drain pipe 69 is secured to the rotor assembly 8 and moves around with it.

Water from the collecting trough flows from the outlet 24 to a water sump 70. Water from the sump is returned to the spray ring 65 by the feed pipe 60 in which is connected a water pump 71, driven by any suitable means. Make-up water is supplied from a water main 72 to the sump 70, and its flow into the sump is controlled by a water float valve 73.

Precooler The precooler 3 comprises a vessel 80 (Figs. l and 2) connected to the refrigerant inlet opening 17 of the separator 4. High pressure refrigerant such as liquid ammonia from the recevier of a compression system is delivered thru a supply pipe 81 to a heat exchanger where it is cooled between an outer jacket 82 and an inner jacket 83 thereof. These jackets may be finned in any suitable manner. The exchanger is located inside of the vessel 80. Refrigerant, cooled to near zero degrees Fahrenheit between the jackets, passes thru passageway 82 in the lower end of the heat exchanger and into the bottom of the vessel 80. Refrigerant is drawn off the top of the vessel thru a pipe 85 leading to an expansion valve 86 thru which the refrigerant is expanded to a lower pressure and returned by the pipe 85 to the inside of the inner jacket 83 of the heat exchanger. Passage thru the expansion valve reduces the temperature of the refrigerant so that in passing thru the exchanger it will cool the high pressure incoming liquid. Liquid refrigerant and gas from the exchanger is conducted to the separator thru a pipe 87 connected between the exchanger and the inlet opening 17 of the separator.

Separator Gas and entrained liquid from the evaporator pass from the top of the evaporator thru the outlet opening 18 to the gas separation chamber 4. The chamber is in the form of a closed upright separation tube 90 (Fig. l) having an inlet 9i (Fig. 2) in the side near the bottom connecting with the evaporator outlet 18, a liquid return opening 92 in the bottom of the separator connecting with the evaporator liquid return opening 20, and a gas outlet 93 in its side near the top which connects with the compression system which has not been shown but may be of any standard and suitable type. The cross sectional free area of the separator tube 90 is such that the rate of fall of the liquid particles in the gas stream rising in and thru the separation chamber will be greater than the upward velocity of such gas stream. A baffle 94 in front of the inlet 9i prevents short circuiting of the wet vapor from the evaporator to the gas outlet 93 and gives the incoming vapor a helical movement `which aids in the gas-liquid separation.

Operation ln the operation of the present device, the motor 40 for operation of the rotor assembly is energized to rotate the shaft a3, 44; water is supplied to the sump 70 from the water main 72, its level in the sump is controlled by the float 73, and this water is circulated over the ice making surface 11 by the circulating water pump 71 and its associated piping including the nozzle ring 65; refrigerant such as liquid ammonia is supplied from the high side of a compression system to the precooler 3, thence, thru the separator 4 to the evaporator 5, and the Vapor from the evaporator has the entrained liquid separated out in the separator l and returned to the compression system.

When the temperature of the freezing surface 11 falls to and below the freezing point of water, ice `will form on the surface. The open gap in the water nozzle ring 65 provides a period during which water is not applied to a portion of the ice surface which allows the ice to dry, harden, and sub-cool. This Dry Ice is swept from the freezing surface by the sweeps 48 and cascades down along the doctor blade 54 and its guard 55 to fall 1nto the bin 2. Ice does not tend to lodge and pack between the sweeps becanse the rake portion of the sweeps trails the rail upon which the sweeps are mounted. Ice is prevented from falling in the water trough by the trough guard 53.

A high rate of heat transfer is promoted by the rapid circulation of the refrigerant across the surface of the shell 10. This is accomplished by the circulation batlle 15 forming an ascending passage and a descending passage between the inner shell 10 and the outer shell 12 of the evaporator 5. Heat delivered to the refrigerant in the ascending passage and the gas formed in 'this passage induces an upward circulation of the refrigerant in the ascending passage and a downward current in the descending passage. Gas and entrained liquid are drawn off the top of the refrigerant adjacent the top end closure annulus 13 and the liquid removed from the `gas and returned Ito the evaporator in the separator 4.

The above construction gives a high rate of heat transfer and a large output of `ice per square foot of ice freezing surface. The ice is dry when removed from the freezing surface and remains dry to the storage bin 2.

Obviously changes may be made in the forms, dimensions and arrangements of the parts of my invention without departing from the principle thereof, the above setting forth only preferred forms of embodiment of my invention.

I claim:

l. An ice making machine comprising .an upright first substantially cylindrical shell for forming ice on the inner surface thereof; an upright second substantially cylindrical shell surrounding said first shell, the diameter of the inner surface of the first shell being a plurality of times greater than the distance between the first and second shells; top and bottom closure annuli, each connected between said shells andJ spacing apart said shells, said shells and said annuli forming a closed annular space; an upright substantially cylindrical baille shell disposed between and spaced from said first and second shells and having passageways between its end portions and said annuli, and forming interconnected ascending and descending passageways for circulation of liquid refrigerant, wherein liquid refrigerant travels upwardly between said first shell and said baille, thence transversely outwardly in said passageway at an upper end portion of said baille, thence downwardly between said baffle and said second shell, and thence transversely inwardly in said passageway at said lower end portion of said baille; means supplying liquid refrigerant to one of said ascending and descending passageways; a gas separator chamber having an inlet in communication with said ascending and descending passageways and at an upper end portion thereof, having a vertically disposed curvilinear baille therein to direct the refrigerant fluid from the inlet in a helical path to separate out the liquid component of the fluid, having a gas discharge outlet means, and having a liquid refrigerant discharge communica-ting with one of said ascending and descending passageways and at a location below the inlet to the gas separator; and means supplying water to the inner surface of said first shell to be frozen into ice.

2. An ice making machine comprising an upright tlrst substantially cylindrical shell for forming ice on the inner surface thereof; an upright second substantially cylindrical shell surrounding said first shell, the diameter of the inner surface of the first shell being a plurality of times greater than the distance between the first and second shell, facilitating mechanical ice removal; top and bottom closure annuli, each connected between said shells, and spacing apart said shells, said shells and said annuli forming a closed unrestricted annular chamber; an upright substantially cylindrical baille shell disposed in said annular chamber, spaced between said first and second shells, and having transverse passageways at its end portions adjacent said annuli, and forming directly interconnected ascending, transverse, descending, and transverse passageways for the circulation of liquid refrigerant, wherein liquid refrigerant circulates upwardly between said rst shell and said baille, thence transversely outwardly in the upper transverse passageway adjacent the upper end portion of said baille, thence downwardly between said baille and said second shell, and thence transversely inwardly in said transverse passageway adjacent the lower end portion of said baille; gas-liquid discharge means connected with said annular chamber and at substantially the vertical level of the top end portion of said baille; and means providing a refrigerant liquid level in said annular chamber with liquid refrigerant ilooding through the transverse passageway at the top end portion of said baille and with gas and entrained liquid refrigerant delivered to said gas-liquid discharge means.

3. An ice making machine comprising an upright ilrst substantially cylindrical shell for forming ice on the inner surface thereof; an upright second substantially cylindrical shell surrounding and spaced from said iirst shell, the diameter of the inner surface of the ilrst shell being a plurality of times greater than the distance between the first and second shell, facilitating mechanical ice removal; top and bottom closure annuli, each connected between said shells, said shells and said annuli forming a closed unrestricted annular chamber; an upright substantially cylindrical baille shell disposed in said annular chamber, spaced between said ilrst and second shells, and having transverse passageways at its end portions, and forming directly interconnected ascending, transverse, descending, and transverse passageways for the circulation of liquid refrigerant, wherein liquid refrigerant circulates upwardly between said iirst shell and said baille, thence transversely outwardly in the upper transverse passageway adjacent the upper end portion of said baille, thence downwardly between said baille and said second shell, and thence transversely inwardly in said transverse passage way adjacent the lower end portion of said baille; a gasliquid separator chamber means connected with said annular chamber and having a substantial portion of its chamber above the vertical level of the top end portion of said baille; and means providing a refrigerant liquid level in said annular chamber with liquid refrigerant flooding through the transverse passageway at the top end portion of said baille and with gas and entrained liquid refrigerant delivered to said gas-liquid separator chamber means.

4. An ice making machine comprising an upright ilrst substantially cylindrical shell for forming ice on the inner surface thereof; an upright second substantially cylindrical shell surrounding said rst shell, the diameter of the inner surface of the first shell being a plurality of times greater than the distance between the iirst and second shell, facilitating mechanical ice removal; top and bottom closure annuli, each connected between said shells, said shells and said annuli forming a closed unrestricted annular chamber; an upright substantially cylindrical baille shell disposed in said annular chamber, spaced between said first and second shells, and having transverse passageways at its end portions, and forming directly interconnected ascending, transverse, descending, and transverse passageways for the circulation of liquid refrigerant, wherein liquid refrigerant circulates upwardly between said ilrst shell and said baille, thence transversely outwardly in the upper transverse passageway adjacent the upper end portion of said baille, thence downwardly between said baille and said second shell, and thence transversely inwardly in said transverse passageway adjacent the lower end portion of said bafile; gasliquid discharge means connected with said annular chamber and at substantially the vertical level of the top end portion of said baille; and means providing a refrigerant liquid level in said annular chamber with liquid refrigerant ilooding through the transverse passageway at the top end portion of said baille and with gas and entrained liquid refrigerant delivered to said gas-liquid discharge means.

References Cited in the ille of this patent UNITED STATES PATENTS 1,635,058 Potter July 5, 1927 2,042,394 Gay May 26, 1936 2,154,905 Kagi Apr. 18, 1939 2,156,426 Brown May 2, 1939 2,387,899 Gruner Oct. 30, 1945 2,462,329 Mojonnier Feb. 22, 1949 2,512,869 McBroom .Tune 27, 1950 2,548,441 Morrison Apr. 10, 1951 2,703,969 Lindsey Mar. 15, 1955 2,712,734 Lees July 12, 1955

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