US3694112A

US3694112A - Rotary valve pump

Info

Publication number: US3694112A
Application number: US80873A
Authority: US
Inventors: David Freedman
Original assignee: New Brunswick Scientific Co Inc
Current assignee: New Brunswick Scientific Co Inc
Priority date: 1970-10-15
Filing date: 1970-10-15
Publication date: 1972-09-26
Anticipated expiration: 1989-09-26

Abstract

A positive displacement pump capable of pumping liquids in which solids are suspended. The pump has a pump housing provided in its interior with a pump chamber which expands during each suction stroke and contracts during each pressure stroke. A housing wall defines part of the pumping chamber and is formed with inlet and outlet ports through which the pump material flows. A valve body oscillates with respect to the latter housing wall for opening and closing each of the ports in the sequence required to achieve the pumping action. A surface of the housing wall at the ports thereof slidably engages the oscillating valve body so that the latter achieves a shearing action to facilitate pumping of liquids in which solids are suspended.

Description

United States Patent Freedman ROTARY VALVE PUMP David Freedman, Highland Park, NJ.

New Brunswick Scientific Co., Inc.

Oct. 15, 1970 Inventor:

Assignee:

Filed:

Appl. N0.:

[4 1 Sept. 26, 1972 Primary Examiner-Robert M. Walker Attorney-Blum, Moscovitz, Friedman & Kaplan [5 7] ABSTRACT A positive displacement pump capable of pumping liquids in which solids are suspended. The pump has a pump housing provided in its interior with a pump chamber which expands during each suction stroke and contracts during each pressure stroke. A housing wall defines part of the pumping chamber and is fonned with inlet and outlet ports through which the pump material flows. A valve body oscillates with respect to the latter housing wall for opening and clos- [56] References Cited ing each of the ports in the sequence required to achieve the pumping action. A surface of the housing UNITED STATES PATENTS wall at the ports thereof slidably engages the oscillating valve body so that the latter achieves a shearing 2 gig: action to facilitate pumping of liquids in which solids d 2,056,902 10/1936 Longenecker ..417/519 are Suspe e 2,516,388 7/1950 Humphreys ..4l7/5l9 X 5 Claims, 8 Drawing Figures a! ii I a g1 :25 42 r ,nr

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sum 2 0F 3 ATTORNEYS ROTARY VALVE PUMP BACKGROUND OF THE INVENTION The present invention relates to pumps.

More particularly, the present invention relates to positive displacement pumps which are required to pump materials such as heavy or viscous liquids in which solids are suspended.

Particular difficulties are encountered in pumps of this latter type because the solids suspended in the liquids interfere with valve operation. More particularly, the pumping of viscous or heavy materials that have suspended particles or solids, strands of substantial length or materials that separate and settle during pumping is normally difficult to pump in a reliable manner. Such materials interfere with the valve operation of the pump and accordingly prevent the continuous feed of such slurries where such continuous feed is necessary or desirable. In certain operations growth occurs in the conduits where the materials are pumped and this requires an arrangement for some degree of shearing or cutting. Strings or strands of mycelium, during the pumping cycle, particularly require some shearing to permit such pumping. Frequently in the heretofore used pumps there is interference with valve operation resulting in intermittent operation and sometimes total blockage. Also a back-flow problem is frequently presented where a valve pump handles this type of slurry which is eliminated with the use of a positive displacement pump of the present invention.

In addition, pumps of the heretofore used type are subjected to excessive frictional forces as a result of the suspended solids and overheating is frequently encountered while at the same time undesirably large amounts of power arerequired for pump operation.

SUMMARY OF THE INVENTION It is a primary object of the invention to provide a positive displacement pump which will avoid the above drawbacks.

In particular it is an object of the present invention to provide a pump of this type which will shear the solids and filamentary material so as to reduce the size thereof and thus facilitate the pumping of liquids in which solids are suspended. I

Thus, it is an object of the present invention to provide a pump which can effectively pump materials such as viscous slurries, heavy sludge, or liquids in which solid matter such as granular and gritty materials, and the like is suspended.

A further object of the present invention is to provide a pump of the above type which can be readily disassembled for cleaning purposes. The objects of the present invention include the provision of a pump which can be readily and simply sterilized using a conventional sterilization medium.

In addition, it is an object of the present invention to provide a pump of the above type which is simple and rugged and which will operate reliably without undesirable interruptions in the operation due to solids suspended in pump liquid while at the same time overheating is avoided and the operation of the pump requires a relatively small amount of power.

According to the invention the positive displacement pump includes a pump housing having in its interior a pump chamber and a reciprocating means coacting therewith for increasing the volume of the pump chamber during each suction stroke and decreasing the volume of the pump chamber during each pressure stroke. A housing wall which defines part of the pump chamber thereof is formed with an inlet port through which material enters the chamber during each suction stroke and an outlet port through which material discharges from the chamber during each pressure stroke. A valve means coacts with these ports for opening the inlet port and closing the outlet port during each suction stroke and for opening the outlet port and closing the inlet port during each pressure stroke. This valve means slidably engages a surface of the latter housing wall at the inlet and outlet ports thereof for imparting a shearing action on particulate matter which facilitates the pumping of liquids in which solids or filamentary materials are suspended. The aforenoted shearing action defines a positive shearing boundary at which the solid materials are cut, free or separated in conjunction with the pressure feed of the fluid materials through the valve. In the case of lengthy filamentary material this will be progressively cut at the shearing boundary thereby eliminating valve interference or blockage caused thereby. The inlet conduit to the shearing boundary is tapered thereto providing requisite pressure build-up of the fluid to such boundary increasing the effectiveness of the shearing operation.

The pump of the present invention is of a simplified design which prevents clogging, accumulation of solid matter and contamination and inherently provides accurate metering and reproducability of flow rates.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. 1 is a fragmentary longitudinal sectional elevation of one possible embodiment of a pump according to the invention;

FIG. 2 is an end view of the pump of FIG. 1 as seen from the left end thereof, taken along line 2-2 of FIG. 1 in the direction of the arrow;

FIG. 3 is a transverse sectional elevation of the pump of FIG. 1 taken along line 3-3 of FIG. 1 in the direction of the arrow;

FIG. 4 shows the upper part of the pump of FIG. 1 at an enlarged scale as compared to FIG. 1 for providing a clear illstration of the valve means and the inlet and outlet ports where the valve means is located;

FIGS. 5 and 5a are respectively fragmentary transverse sections of the structure of FIG. 4 taken along line 5-5 of FIG. 4 in the direction of the arrow and showing different stages of the pump operation at the inlet port; and

FIGS. .5 and 6a are fragmentary transverse sectional elevations taken along line 6-6 of FIG. 4 in the direction of the arrow and showing operations at the outlet port at different stages in the operation, FIGS. 5 and 6 illustrating different parts of the valve body at one position thereof and FIGS. 5a and 6a illustrating different parts of the valve body at another position thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, the particular pump of the invention which is illustrated therein is shown,

can also pump material such as slurries or any liquid in which a particulate solid matter is suspended. The positive displacement pump of the invention is reversible and self-priming, and atthe same time it can be readily disassembled for cleaning and sterilization purposes, as will be apparent from the description which follows.

the like are suspended, and the pump of the invention I Referring to FIG. 1, there is fragmentarily illustrated therein a driving motor which has an output shaft 12 which through a suitable coupling 14 drives a rotary shaft 16 of the pump 18 of the invention. The pump has a housing 20 opposed walls of which are provided with suitable bearings for the drive shaft 16.

In the illustrated example the drive shaft 16 fixedly carries a rotary eccentric 22, which may be keyed to the shaft 16 and held at a given axial position thereon by fixed collars, for example, as illustrated in FIGS. 1 and 3.

The housing 20 of the pump has an interior transverse wall 24'formed with a bore which is lined with a bearing sleeve 26. A rod 28 is adapted to reciprocate in the sleeve 26 and terminates at its bottom end in an enlarged'plate 30 which is maintained in engagement with the eccentric 22 by a spring 32. Thus, during rotation of the drive shaft 16 the rod 28 will reciprocate, as shown by the double-headed arrow in FIG. 1.

At the region of its upper end, the rod 28 is formed with an annular groove 34. This groove is adapted to receive the inwardly directed edge regions 36 of a connecting member 38 which is formed with a T-slot for receiving the upper end of the rod 28 so that the connecting body 38 will reciprocate together with the rod 28. This connecting body 38 is fixed to a flexible resilient diaphragm 40 fixed at its outer periphery to the downwardly directed interior surface of an upper housing wall 42. For this purpose a ring 44 engages the lower surface of the diaphragm 40, and suitable bolts 46 pass through openings of the ring 44 and the diaphragm 40 into threaded bores of the wall 42.

Just above the diaphragm 40, the pump housing has in its interior the pumping chamber 48 which is defined in part by the housing wall 42. The diaphragm 40 forms a reciprocating means which reciprocates to increase and decrease the volume of the chamber 48. Thus the .pump will carry out a suction stroke each time the pass through bores of the wall 42 into threaded bores 52 formed in the lower part of the housing 20. This body 42 is formed with a cylindrical bore 54 which receives a valve means 56 of the invention. The valve means 56 has a fairly close fit within the bore 54 for a purpose referred to below. The wall 42 is formed with an inlet port 58 and a outlet port 60. These ports extend transversely across the bore 54. Suitable fittings 62 and 64 (FIG. 1) are threaded into the ports 58 and .60 for respectively directing the pump material to and from the pump 18.

The valve means 56 is formed with a pair of

valve openings

66 and 68. The openings taper in a downward direction, and the

ports

58 and 60 respectively have lower end portions 580 and 600 which are smaller than their upper portions.

The valve means 56 is formed at the exterior of its cylindrical body with a plurality of grooves receiving the sealing rings 70. At the region of its outer ends, the valve body is surrounded by a pair of plates 72 releasably maintained in engagement with exterior surface portions of the housing 20 by snap rings 74 situated in suitable grooves of the valve body. When the snap rings 74 are removed the entire valve means 56 can very easily be slipped out of the bore 54.

An oscillating means described in greater detail below oscillates the valve means 56 between the positions shown in FIGS. 5 and 6, on the one hand, and in FIGS. 5a and 6a on the other hand. Thus, the valve body 56 is oscillated angularly in a clockwise direction, as viewed in FIGS. 5 and 6, to the position shown in FIG. 6 where the opening 68 communicates with the lower portion 60a of the outlet port 60, so that at this time the reciprocating means formed by the diaphragm 40 is moving upwardly along its pressure stroke to displace the pumped material out through the outlet 60. As is apparent from FIG. 5, the lower end of the valve opening 66 at this time is displaced beyond the lower portion 58a of the inlet port 58 so that the inlet port is closed and thus material cannot enter through the inlet port.

In the position of the valve means shown in FIGS. 5a and 6a, the opening 66 communicates with the lower portion 58a of the inlet port 58 while the opening 68 is displaced beyond the lower portion 60a of the outlet port 60, and at this time the pump is carrying out its suction stroke increasing the volume of the pump chamber and sucking the material in through the inlet port while the outlet port is closed.

The inner surface of the bore 54 of wall 42, at the

ports

58 and 60, is located in sufficiently close proximity to the exterior surface of the valve means 56 to provide the equivalent of a sliding action therewith, so that as the valve means 56 oscillates angularly it will have a shearing action'with the cooperating surface of the wall 42 at the-inlet and outlet ports thereof to define a positive shearing boundary thereat. As a result of this shearing action at the shearing boundary it is possible to shear solid matter suspended in the pumped liquid, thus preventing this solid matter from jamming or otherwise interferring with the operation of the pump. In this way it becomes possible for the pump of the invention to effectively pump material such as sludges, slurries, and the like, or any materials in which solids such as garbage or the like are suspended. The

valve openings

66 and 68 taper to the shearing boundary providing pressure build-up of the fluid to such boundary to increase the effectiveness of the shearing ac- 56 includes an elongated crank arm 76 fixed to a free end of the valve means 56 positioned at the exterior of the housing 42. As is apparent particularly from FIG. 2, the lower end region of the crank arm 76 is formed with an elongated slot or guide 78 receiving a slide block 80. This slide block is carried by a pivot pin 82 which is in turn carried by a rotary crank arm 84 fixed to the left end of the drive shaft 16 as viewed in FIG. 1. Thus as the drive shaft 16 rotates, the crank arm 76 will be oscillated back and forth between the solid and dotdash line position shown in FIG. 2, bringing about the angular oscillation of the valve means 56 between the positions shown in FIGS. 5 and 6, on the one hand, and FIGS. 5a and 60, on the other hand, as described above. I

The body 42, with tubing and vessels intact can be readily removed from the housing 20 for steam sterilization as will be apparent to those skilled in the art. Furthermore, the pump can be steani sterilized in situ by steaming directly through the head chamber 48 while the pump is in operation.

Since the crank arm 76 can easily be displaced from the slide block 80, it is a simple matter to remove the valve body 56 from the bore 54 upon removal of the snap rings 74, as pointed out above. To remove the body 42, the bolts 50 are removed to permit the body to be displaced from the remainder of the housing, as indicated in FIG. 3. The shaft 16 at this time can be turned to locate the maximum throw of the eccentric 22 in the upper position to displace the rod 28 somewhat higher than the position shown in FIG. 3, facilitating removal of the connecting body 38 from the top of the rod 28, so that the body 42 can be removed with the diaphragm 40 intact. The bolts 46 can be removed so as to give access to the pumping chamber 48, if desired. Thus the valve means can be removed and replaced by itself or the pump can readily be disassembled to give quick and easy access to the body 42 and connected components for sterilization.

It will be noted from FIGS. 5, 5a, 6, and 6a, that the valve bores 66 and 68 each have opposed ends one of which is smaller than the other. The actual alternate closing of these bores takes place only at the smaller ends thereof. The larger ends of the

bores

66 and 68 remain at all times at least partly in communication with the

bores

58 and 60 in the wall 42. Therefore, the closing and opening of the valve bores takes place only at their Smaller ends while continuous shearing action takes place at the larger ends of the bores.

What is claimed is:

1. In a positive displacement pump, a pump housing having a pumping chamber, and reciprocating means in said chamber for increasing the volume thereof during each suction stroke of the pump and for decreasing the volume thereof during each pressure stroke of the pump, said housing having a wall defining part of said pumping chamber and formed with inlet and outlet ports for respectively directing the material which is to be pumped into said chamber through said inlet port during each suction stroke and out of said chamber through said outlet port during each pressure stroke, and elongated valve means coacting with said wall at said ports thereof for closing said outlet port and opening said inlet port during each suction stroke and closing said inlet port while opening said outlet port during each pressure stroke, said valve means and said wall of said housing having at said ports coacting shearing surfaces for providing a shearing action to facilitate pumping of liquids having solids suspended therein, said inlet and outlet ports both extending perpendicularly with respect to said elongated valve means and being axially spaced from each other along said elongated valve means, and said valve means being formed with valve openings which respectively coact with said ports and which also are axially displaced along said elongated valve means, oscillating means coating with said valve means for oscillating the latter to achieve the shearing action, said oscillating means providing for said valve means an angular oscillation about a predetermined axis, and said valve means including an elongated valve body of cylindrical configuration having an axis coinciding with said axis about which said valve means oscillates, said valve body having an exterior cylindrical surface, said wall being formed with a cylindrical bore in which said valve body is turnable, and said surface of said wall forming part of said bore thereof and being situated at said inlet and outlet ports, each of said valve openings having opposed ends one of which is smaller than the other and said valve openings continuously communicating at their larger ends with said ports for providing continuous shearing action while closing and opening of said valve openings takes place at said smaller ends thereof.

2. In a positive displacement pump, a pump housing having a pumping chamber, and reciprocating means in said chamber for increasing the volume thereof during each suction stroke of the pump and for decreasing the volume thereof during each pressure stroke of the pump, said housing having a wall defining part of said pumping chamber and formed with inlet and outlet ports for respectively directing the material which is to be pumped into said chamber through said inlet port during each suction stroke and out of said chamber through said outlet port during each pressure stroke, and valve means coacting with said wall at said ports thereof for closing said outlet port and opening said inlet ports during each suction stroke and closing said inlet port while opening said outlet port during each pressure stroke, said valve means and said wall of said housing having at said ports coacting shearing surfaces for providing a shearing action to facilitate pumping of liquids having solids suspended therein, an oscillating means coacting with said valve means for oscillating the latter to achieve the shearing action, said oscillating means providing for said valve means an angular oscillation about a predetermined axis, said valve means including an elongated valve body of cylindrical configuration having an axis coinciding with said axis about which said valve means oscillates, and said valve body having an exterior cylindrical surface, said wall being 3. The combination of claim 2 and wherein said valve openings taper and respectively have smaller ends directed toward said chamber. Y

4. The combination of claim 3 and wherein said wall of said housing is removable connected with the remainder thereof to facilitate cleaning of the pump.

5. The combination of claim 3 and wherein said valve body is removable from said bore for facilitating cleaning of the pump.

Claims

2. In a positive displacement pump, a pump housing having a pumping chamber, and reciprocating means in said chamber for increasing the volume thereof during each suction stroke of the pump and for decreasing the volUme thereof during each pressure stroke of the pump, said housing having a wall defining part of said pumping chamber and formed with inlet and outlet ports for respectively directing the material which is to be pumped into said chamber through said inlet port during each suction stroke and out of said chamber through said outlet port during each pressure stroke, and valve means coacting with said wall at said ports thereof for closing said outlet port and opening said inlet ports during each suction stroke and closing said inlet port while opening said outlet port during each pressure stroke, said valve means and said wall of said housing having at said ports coacting shearing surfaces for providing a shearing action to facilitate pumping of liquids having solids suspended therein, an oscillating means coacting with said valve means for oscillating the latter to achieve the shearing action, said oscillating means providing for said valve means an angular oscillation about a predetermined axis, said valve means including an elongated valve body of cylindrical configuration having an axis coinciding with said axis about which said valve means oscillates, and said valve body having an exterior cylindrical surface, said wall being formed with a cylindrical bore in which said valve body is turnable, and said surface of said wall forming part of said bore thereof and being situated at said inlet and outlet ports, said inlet and outlet ports extending transversely across said bore, said valve body having valve openings axially displaced one with respect to the other with one of said valve openings communicating with said inlet port during each suction stroke and the other of said valve openings communicating with said outlet port during each pressure stroke.

3. The combination of claim 2 and wherein said valve openings taper and respectively have smaller ends directed toward said chamber.