US2642001A - Pump by-passing assemblage - Google Patents

Description

June 16, 1953 v. F. DALE ETAL 2,642,001

I PUMP BY-PASSING ASSEMBLAGE Filed Jan. 25, 1950 2 Sheets-Sheet l INVENTORS B MAE fl'ww Arron/v5 Y5.

Patented June 16, 1953 UNITED STATES PATENT OFFICE Y Y 'c,642,001;

\ PUMR BY -P AS SING ASSEMBLAGE Vernon F. Dale "and George W. Reed,nalaska, Wis., assignors to The Bump Pump 00., La

Crosse, Wis., a corporation of Wisconsin Application January 25, 1950, Serial No. 140,466

teams. (01. 103-450 conduits or the like, and relates more specificallyto improvements in the construction. and operation -of positive displacement liquid propelling pumps especiallyadapted to handle commodities such as milk.

The primary object of the present invention is to provide an improved rotary positive displacement pump which is simple, compact and durable in construction, and. which is also highly efficient in operation.

It has heretofore been rather common practice toprovide various types of pumps with some form of relief mechanism for by-passing fluid from the discharge to the intake sides of the pistons when excessive pressures are established at pump outlet or discharge. When applying such pressure relief devices to rotary positive displacement pumps for liquid, it has been customary to provide a spring pressed bypass valve operable by the pump discharge pressure and located in a liquidreturn conduit some distance fromthe impeller displacement chamber, in order to accomplish the desired result. While this type of relief mechanism functions 'to release theabnormal pressures in a. fairly satisfactory manner, it is objectionable when used in pumps for transporting commodities such as milk which are apt to become rancid if pocketed in a confined space for any length of time, as is often the case when relatively long by-pass conduits leading to and from the relief valve are employed and this valve is relatively complicated anddifiicult to clean the previous pressure release 7 and by-pass mechanot-opened for a prolonged period. Besides being nisms are therefore not sufiiciently sanitary and are especially unsuitable for propelling milk and I similar delicate commodities which-are subject-to spoilage.

It is therefore an important object of our presentinventionto providean improved pump; and relief unit which definitely eliminates undesirable pocketing of liquid, and which is adapted to. be

.mainta-ined in most sanitary condition at all times.

Another important object of the invention is to provide an improved positive displacement rotary pump having-an eifective pressure relief device incorporateddirectly therein, and adapted to establish a by-pass passage of limited size,.only whenabnorinal discharge pressures are attained.

A further important object of this invention is .to provide a conveniently adjustable liquid bypass mechanism for rotary impeller positive displacement pumps, wherein pocketing of liquid is avoided at all times, and which functions quickly and automatically to release abnormal liquid pressures. I Still another objectof our invention is to proaccessible for inspection and cleaning, and. which may be manufactured and sold at moderate cost for diverse purposes. I

An additional object of the present invention is to provide a sanitary rotary liquid pump of the double impeller type, which is composed of only a few simple and sturdy parts and which requires minimum attention in order to maintain the same in effective operating condition.

These and other more specific objects and advantages of the present invention, will be apparent from the following detailed description.

' A clear conceptionof the improvements constituting our present invention, and of the construction and operation of a typical pump unitembodying the same, may be had by referring to the drawings accompanying and forminga part of this specification in which like reference charactersdesignate thesame or similar parts in the various views Fig. l is an end view'of atypical double impeller rotary positive displacement liquid pump and by-pass unit constructed in-ac'cordance with the invention; I q v Fig. 2 is a central transverse section taken through the unit of Fig. l along the line 2-2, and showing a by-pass adjusting-wrench in dot-anddash lines; and

Fig. 3 is a fragmentary section similar to that 1 of Fig; 2, taken through the by-pass or pressure 'relief'mecha'nism, but showing the pressure redesire to unnecessarily restrict the utility'by' vir tue of this limiteddisclosure, and it ismoreover contemplated that descriptive. terms used herein be given the broadest possible interpretation consistent with the disclosure.

Referring to the drawings, the typical double impeller rotary liquid pump and by-pass unit shown therein comprises in general, a main casing composed of a mid-section 6 and two opposed end closures or sections I, 8 all coacting with each other to produce a displacement chamber 9 having a liquid inlet conduit I and a discharge or outlet conduit I I communicating with the opposite sides thereof; a pair of oppositely rotatable constantly sealingly contacting rotors or impellers I2, I3 snugly confined and revolvable within the chamber 9 and adapted to be driven by shafts I I extending through the closure section I; a rigid movable plug or cylindrical member I5 slidably confined within a central bore I6 formed in the closure section 8 mid-way between the conduits I0, II, and overlapping the contact zone between the impellers I2, I3; and adjustable means for normally urging the member I5 into sealing engagement with the adjacent end faces of the impellers I2, I3.

vThe three sections 6, I, 8 are adapted to be firmly but detachably clamped to each other with the aid of studs I8 and nuts I9, 50 that the plane inner end surfaces 28, 2i of the closure sections 'I,'8- respectively will sealingly engage the adjacent end surfaces of the impellers I2, I3; and the peripheral surfaces of the impeller lobes are likewise sealingly cooperable with the bores 22 of the casing mid-section 5. The periphery of the rigid byepass plug or member I5 is provided with a resilient sealing ring 23which slidably engages the bore I6 of the face plate or closure section 8, and the shafts I4 which normally rotate the impellers I2, I3 in opposite directions as indicated by the arrows in Fig. 1, may be driven in any suitable manner. The outer extremities of the conduits I0, Il may also be provided with screw threads 24 for facilitating attachment to liquid supply and discharge sources with the aid of quick-detachable couplings.

The adjustable means for constantly but resiliently urging the plug member I5 inwardly toward the impellers I2, I3, comprises a U-shaped bracket or yoke 25 which is secured at its oppo- 4 justed by manipulating the screw 3| with the aid of the wrench 32, so as to normally maintain the inner face of the valve member I5 in the plane of the inner surface 21 of the closure plate or section 8 as in Fig. 2, thus normally producing sealing engagement between the member I5 and the impellers I2, I3 at the zone of contact of these impellers with each other while permitting the member I5 to move outwardly from this zone in case excessive pressure is created in the discharge space. If the discharge pressure does e not exceed that required to displace the by-pass site ends to the casing section 3 by means of screws 25 and the medial portion of which is provided with an internally screw threaded boss 21; a helical compression spring 28 one end of which coacts with a socket 29 formed in the member I5 while its opposite end embraces and re- 4 acts against a retainer 30; and an adjusting screw 3I coacting with the screw threads of the boss 21 and with a central recess in the retainer 30. The outer end of the adjusting screw 3| is provided with a polygonal socket to which an adjusting wrench 32 in Fig. 2, in order to vary the compression of the spring 28 and to thereby vary the pressure required to displace the valve member I5, and the bracket attaching screws 26 may also be provided with similar polygonal manipulating sockets. A lock nut 33 may also be applied to the screw 31 and caused to coact with the boss 21 as shown, in order to maintain the retainer in adju'sted position.

When the improved pump has been properly constructed and assembled as hereinabove described, and the inlet and outlet conduits I0, II have been connected to a liquid transporting line with the aid of the screw threads 24, the 1mpellers I2, I3 may be rotated by means of the driving shafts I4 so as to cause liquid to be sucked into the displacement chamber 9 through the conduit I0 and to be discharged through the conduit II. 'The spring 28 should then be admay be applied as indicated member I5, this member will remain in the position shown in Fig. 2 and no pocket or appreciable clearance will exist between the impellers I2, I3

.and the relief member I5; but when the delivery pressure rises for any reason to an extent sulficient to overcome that exerted by the spring 28, the member I5. will be lifted more or less as depicted in Fig. 3 so as to permit immediate release of the excess discharge pressure by allowing liquid to return directly to the inlet space of the pump. V

It will thus be apparent that we have in fact provided acombined pump and relief valve assemblage wherein excessive discharge pressure above any established value, will be quickly and automatically relieved without introducing objectionable pockets or space wherein liquid can accumulate for prolonged periods of time. As soon as the abnormal pressure is disbursed, the spring 28 will immediately return the member E5 to sealing position and will wipe out the clearance or by-pass space, so that the pump may thereafter operate normally with the impellers I2, I3 totally sealed. The packing ring 23 positively prevents undesirable escape of liquid through the bore I6 and is preferably located as near as possible to. the inner face of the member I5 in order to eliminate undesirable pocketing of liquid; and by forming the member cylindrical manufacture and assembly thereof are facilitated. The entire pump structure is durable and of utmost simplicity, and all parts thereof are obviously readily accessible for inspection and clearing thus making it possible to maintain the assemblage in most sanitary condition at all times. The improved relief mechanism has proven highly successful and satisfactory in actual use as applied to milk transporting or pumping units, but may be advantageously and readily applied to other types of pumps for diverse purposes.

It should be understood that it is not desired to limit this invention to the exact details of construction and operation of the typical pumping unit, herein shown and described, for various modifications within the scope of the appended claims may occur to persons skilled in the art.

We claim:

1. In a rotary pump, a casing having a midsection and opposed end sections secured thereto, said mid-section being provided with adjoining parallel bores communicating at the opposite sides of their junction with liquid inlet and outlet conduits and both of said end sections having plane parallel surfaces enclosing the opposite ends of said mid-section bores, one of said end sections being provided with a bore disposed coaxially of said junction and having-a diameter approximately equal to the distance between the axes of said mid-section bores while the other end section is provided with spaced bearings disposed coaxially of said adjoining mid-section bores, a positive displacement rotor mounted in each of said adjoining mid-section bores and normally sealingly engaging said end section plane surfaces and each other between said inlet and outlet conduits, each of said rotors having a supporting shaft projecting from one side only and journalled inone of said bearings While its opposite side is plane and devoid of projections, a

cylindrical piston member snugly slidably confined within said end section bore and having a plane inner end surface normally sealingly cooperable with said plane rotor end surfaces while its outer end surface is constantly exposed to the ambient atmosphere, and means for resiliently urging said member toward said rotors.

2. In .a rotary pump, a casing having a midsection and opposed end sections secured thereto, said mid-section being provided with adjoining parallel bores communicating at the opposite sides of their junction with liquid inlet and outlet conduits and both of said end sections having plane parallel surfaces enclosing the opposite ends of said mid-section bores, one of said end sections being provided with a through bore disposed coaxially of said junction and having a diameter approximately equal to the distance between the axes of said mid-section bores while the other end section is provided with spaced bearings disposed coaxially of said adjoining midsection bores, a positive displacement rotor mounted in each of said adjoining mid-section bores and normally sealingly engaging said end section plane surfaces and each other between said inlet and outlet conduits, each of said rotors having a supporting shaft projecting from one side only and journalled in one of said bearings while its opposite side is plane and devoid of projections, a cylindrical piston member snugly slidably confined within said end section bore and having .a central outer recess and a plane inner end surface normally sealingly cooperable with said plane rotor end surfaces While its outer end surface is constantly exposed to the ambient atmosphere, a helical compression spring disposed externally of the casing for urging said member toward said rotor and having one end confined within said recess while its opposite end is provided with a reaction plug, and means coacting with said plug for varying the tension of said spring.

VERNON F. DALE. GEORGE W. REED.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 885,783 Palmer Apr. 28, 1908 1,694,805 Wiltse Dec. 11, 1928 1,927,395 Edwards Sept. 19, 1933 2,134,158 Seyvertsen Oct. 25, 1938 2,380,783 Painter July 31, 1945 2,434,135 Witchger Jan. 6, 1948 2,477,797 Girz et a1 Aug. 2, 1949

Images