Adjustable pressure extrusion pump

Abstract

 An extrusion pump for slurries and the like of the Moineau type includes an elastomeric stator (38) that is detachably mounted in a radially adjustable housing (16) for radially adjusting the pressure of the stator on the rotor therein.

Description

BACKGROUND OF THE INVENTION

[0001] The present invention relates generally to pumps and pertains particularly to extrusion pumps.

[0002] Slurries of concrete, plaster and similar materials are difficult to pump with conventional impeller pumps. Such materials are typically handled by an extrusion pump, generally referred to as a Moineau pump, which includes a rigid cylinder or cylindrical housing in which is mounted an elastomeric pump stator In an unstressed condition. The stator includes a spiral interior bore corresponding to the external shape of an elongated spiral shaped rotor or impeller, which passes through the cyli nder. The rotor is preferably formed of steel or the like, and upon rotation deforms the interior of the stator, so achieving a pumping action. Such pumps in accordance with the prior art are shown in U. S. Patent Nos. 3, 006, 615 issued October 21, 1961 to W. R. Mason, Jr., and 3,093,364 issued June 11, 1963 to Schoonover.

[0003] Such pumps have been, and are extensively used in the construction industry today. One drawback to such pumps is that the bore of the stator wears at a rapid rate requiring replacement quite frequently. Because of the structure this also requires, replacement of the housing of the pump section which as previously described generally comprises a cylindrical housing formed of a section of pipe on the order of three to four inches in diameter in which the elastomeric stator is molded. The frequent and continuous replacement of this unit becomes qulte expensive over a period of time.

[0004] Another drawback to such prior art devices is the fact that as the stator bore wears the pressure of the pump begins to drop. Thus, a new pump stator assembly begins at optimum pressure with the pressure dropping off to a substantially unworkable pressure at the end of the life of the stator.

[0005] It is therefore desirable that means be available which reduces the cost of replacement of such pump units and reduces the pressure loss during its lifetime.

SUMMARY AND OBJECTS OF THE INVENTION

[0006] It is therefore the primary object of the invention to overcome problems of the prior art.

[0007] Another object of the invention is to provide an improved extrusion pump having a stator that is replaceable independent of the housing.

[0008] A further object of the invention is to provide an improved extrusion pump having a stator that is adjustable on the rotor to maintain or increase the pressure of the pump.

[0009] In accordance with the primary aspect of the present invention an extrusion pump includes an elastomeric stator that is detachably mounted in an adjustable housing such that the stator can be replaced independent of the housing and the housing is radially adjustable to adjust the pressure of the stator on the rotor, and thereby the . pressure of the pump.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other objects and advantages of the invention will become apparent from the following description when read in conjunction with the drawings wherein:

Figure 1 is a side elevation view of the pump.

Figure 2 is an enlarged side elevation view, partially cut away, of one end of the pump.

Figure 3 is an enlarged sectional view taken on line 3-3 of Figure 1..

Figure 4 is an enlarged sectional view taken on line 4-4 of Figure 1.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0011] Turning now to the drawings, illustrated in Figure 1 is a pumping unit designated generally by the numeral 10, showing an exemplary preferred embodiment of the invention. The unit as illustrated, replaces units as disclosed in the aforementioned Mason and Schoonover patents. The unit 10 is detachably mounted between an inlet chamber or hopper 12 shown in phantom. A slurry is fed into the pump unit at 12 and exits the unit at 14 and generally through a flexible hose or the like, and some form of nozzle or other spraying or application device, not shown.

[0012] The unit includes a generally cylindrical housing 15. The basic elements of the housing 15 are three identical segments 16 of a generally arcuate or semicircular configuration, each having a stub flange 18 extending along one edge, which cooperatively engages with a cap flange 20 along the opposite edge of an adjacent identical housing segment. The ends of each housing segment are formed or shaped with cylindrical outer surfaces or sections 22 and 24, for the purpose of receiving a pair of identical circular or band clamps 26. These end portions additionally provide means for receiving end caps or adapters 28 and 30, each including a threaded cylindrical portion 32 and 34 respectively, for fitting into the inlet and outlet sections 12 and 14 of the pump system or assembly. Thus, the unit replaces the conventional pipe section having a fixed molded liner of the prior art.

[0013] The housing 15 as best seen in Figures 3 and 4 has an inner, generally cylindrical chamber defined by an inner arcuate surface 36 of the sections. The sections with the flange construction form a generally cylindrical chamber having a longitudinal groove or slot along the edge (i.e. formed between the flanges) of each adjacent section, for receiving a replaceable, generally cylindrical liner 38 having a plurality of ribs 40 extending along the length thereof on the outer surface. These ribs extend between the flanges of the adjacent sections of the housing and are gripped therebetween for retaining the liner in the housing and prevent rotation thereof. The liner is thus detachably mounted within the housing and is easily replaceable. The housing is held together around the inner lining 38 and is adjustable therewith by means of the clamps 26.

[0014] The inner lining 38 is of an elastomeric material and is formed with a helical shaped bore 42 extending the length thereof. The preferred form is that of a double helix, although a single or multiple helix can be used. The liner is preferably constructed of a resilient, abrasion resistant material such as molded rubber or polyurethane, or similar plastic materials. The shore hardness of the material can be selected for different applications and for optimum wear pressure adjustment and the like.

[0015] A pumping rotor 44, also having a helical configuration, is mounted within the helical bore 42 of the resilient liner 38. This rotor rotates within the liner relative to the liner deforming the liner imparting pumping action to fluidized medium within the pump chamber. A drive shaft 52 is drivingly connected to the rotor 44 and is connected to a suitable source of power such as a prime mover.

[0016] As the liner wears, the pressure developed in the pump gradually reduces along with the gradual wear of the liner. With the present invention, however, the radial dimensions of the bore 42 may be continually adjusted radially Inward over a large range of adjustment to maintain a higher pressure within the pump. This radial compression adjustment of the liner Is accomplished by adjustably tightening the clamps 26 on the outer housing, thus pulling segments 16 of the housing Inward for adjustment of the liner. Because of the construction of the housing and the liner itself the segments are pulled inward at an equal rate and results In a uniform, substantially equal adjustment of the liner. Once the maximum adjustment of the liner has been utilized, the liner is removed and a new liner is placed In the housing.

[0017] The end caps 28 and 30 are held in place by a plurality of elongated bolts 46 which extend through the bore in lugs 48 on the end cap 30 and threadably engage bores in lugs 50 on the end cap 28.

[0018] With the present Invention the manufacture of the combined liner and housing as in the prior art is eliminated. Each machine is provided with a simple, single, adjustable housing unit 10 which replaces the conventional combined stator and housing unit. Replaceable liners are then manufactured to fit the housing and only the liner need be replaced when excessive wear has occurred. This considerably reduces maintenance costs of such units since only the liner itself need be manufactured after the initial housing or a single housing unit has been supplied.

[0019] The present invention provides the additional feature of the adjustability which not only increases the life of the particular inserts or liners, but also provides the capability of adjusting the pressure output of the pump.

[0020] In order to replace a liner, the housing unit may simply be removed from the pumping unit, taken apart and the liner replaced. The entire unit may be removed, or simply the center section. The center section may be removed by removing bolts 46 and separating the end caps 28 and 30. The clamps 26 may then be removed and the liner 38 removed from Inside the segments of the housing and discarded. A new liner is then Inserted in place and the clamps 26 again placed around the housing segments and secured in place. Appropriate adjustment then may be accomplished by adjusting the clamps 26 to achieve the desired pump pressure.

[0021] While I have illustrated and described my Invention by means of specific embodiments, it Is to be understood that numerous changes and modifications may be made therein without departing from the scope of the Invention as defined in the appended claims.

Claims

1. An adjustable cavity pump comprising:

an elongated housing having a generally cylindrical chamber,

an elongated elastomeric stator having a helical bore for receiving a helical rotor mounted in said chamber, and

said housing including adjusting means for adjusting the diameter of said helical bore.

2. The adjustable cavity pump of claim 1 wherein said stator is detachably mounted In said chamber.

3. The adjustable cavity pump of claim 1 wherein said housing is defined by a plurality of identical segments, and

said adjusting means comprises clamping means for adjustable movement of said housing segments radially inward and outward.

4. The adjustable cavity pump of claim 1 wherein:

said housing defines a plurality of grooves extending the length of the cylindrical cavity, and

said stator includes a plurality of radially extending lugs engaging said grooves for preventing rotation of .he stator.

5. The adjustable cavity pump of claim 3, wherein said housing segments each Include a butt flange extending along one longitudinal edge and a cap flange extending along the other longitudinal edge,
the butt and cap flanges on the adjacent segments cooperatively engaging for defining a longitudinal groove and for guidance of said housing members radially inward and outwardly.

6. The adjustable cavity pump of claim 5 including a pair of the end caps detachably mounted on said housing unit for defining and including inlet and outlet ports for the pump chamber.

7. The adjustable cavity pump of claim 6, wherein said housing includes a substantially cylindrical outer surface at each end thereof and including a clamp extending around each of said cylindrical surfaces, and said clamp being radially adjustable.

Drawing