GB1600465A

GB1600465A - Pumping apparatus for moist granular building material

Info

Publication number: GB1600465A
Application number: GB1958678A
Authority: GB
Original assignee: Thomsen Equipment Co
Current assignee: Thomsen Equipment Co
Priority date: 1977-09-22
Filing date: 1978-05-15
Publication date: 1981-10-14
Also published as: CA1108008A; GB1600466A; GB1600467A

Description

(54) PUMPING APPARATUS FOR MOIST GRANULAR BUILDING MATERIAL (71) We, THOMSEN EQUIPMENT COMPANY, a corporation organised under the laws of the State of California, U.S.A., of 130 West Victoria, Gardena, California 90248, U.S.A., do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to apparatus for pumping a moist granular building material, for example plaster, concrete or mortar.

The pumping apparatus of the present invention is an improvement over the pump disclosed in Patent No. 1,068,863, which discloses a mobile pump that has been widely accepted. The pump disclosed in the prior Patent is a hydraulically operated pistoncylinder pump, which includes a material or concrete chamber having a single control valve element for controlling charging and discharging of the material in the material chamber. The material chamber is provided for housing a single control element or what is commonly known as a flapper element. The flapper element may be a simple plate that performs the desired function of controlling charging and discharging the material. The conveyance of material through the material chamber is an important consideration in the construction of a concrete pump.

According to this invention there is provided apparatus for pumping moist granular building material for example plaster, concrete, or mortar, and including: first and second pumping units; a housing having a material inlet and a material outlet arranged on opposite sides of an internal, cylindrical chamber defined in the housing, the housing also having means connecting the chamber with the pumping units; means for charging the chamber through the inlet with the material to be pumped;; a plate-like control member swingably mounted in the chamber to divide it into two oscillating porlions and allowing the portions to conduct the material from the inlet to one of the pumping units by way of the connecting means and simultaneously to conduct the material from the other pumping unit to the outlet by way of the connecting means, the control member having lateral faces and a pair of trunnions extending in opposite directions parallel with the lateral faces, the control member swinging about the trunnion axes and being in one piece, each lateral face having a concave area for mating with the adjacent arcuate wall surface of the chamber for reducing the flow restriction of the material conveyed through the chamber; and automatic means for operating the pumping units and for swinging the control member in preselected timed relationship therewith.

The invention also includes apparatus for pumping a moist granular building material, for example plaster, concrete, or mortar, and including: first and second pumping units; a material housing having a substantially cylindrical chamber internally thereof, the housing including a material inlet and a material outlet communicating with the chamber, the housing also having means con-' necting the chamber with the pumping units; means for charging the chamber with the material to be pumped through the inlet;; a valve element rotatably mounted within the chamber and extending into sliding engagement with the chamber wall for controlling flow of material at the inlet and the outlet so as to divide the chamber for alternately allowing the divided portions to function with the pumping units as a means to charge the material therein and to discharge the material therefrom, the valve element being arranged in the chamber relative to the inlet and the outlet so as to isolate the portion of the chamber discharging material from communication with the charging means but in communication with the outlet, the valve element being a blade element having aligned trunnions and being rotatably mounted thereby and having oppositely contoured concave faces for mating with the opposed arcuate walls of the chamber for reducing flow restriction of the material conveyed through the chamber; and automatic means for operating the pumping units and for changing the position of the valve element in preselected timed relationship therewith. The control member or valve element is contoured along with shaping the chamber in a mating relationship for minimizing flow restriction of the material through the chamber. The control member or valve element may be in one piece, permitting it to be machined so as to control its concentricities closely.

The housing of the valve element or control member may have a removable cover permitting the control member or valve element to be readily removed for servicing. In addition, the cover opening allows the interior of the housing for mounting the control member or valve element to be readily machined and thereby simplifies installation of wear plates for the control member or valve element. More efficient operation of the pump may be realized by locating a tank for storing lubrication medium or water for the pumping units so that it is directly connected to the cylinders thereof, so eliminating the need for any additional power source for conveying the medium to the point of use, such as when the lubricating medium is at a remote location from the pump units.

In addition, the relocation of the point of application of the driving hydraulic fluid for the piston-cylinder pump units increases the overall efficiency of the hydraulic system and eliminates the need for hydraulic seals required in prior art hydraulic systems.

The pump units may be in the form of piston-cylinder units wherein the cylinders are in direct communication with the chamber and a closed volume is defined behind the reciprocating piston heads.

The invention will now be described by way of example with reference to the drawings, in which: FIG. 1 is a top plan with a portion shown in section, of a pump in accordance with the invention; FIG. 2 is a cross-section of a material chamber on plane 2-2 of Fig. 1; FIG. 3 is a cross-section of the material chamber on plane 3-3 of Fig. 2; FIGS. 4a and 4b when aligned as indicated comprise a view, partly in section, through an entire pumping unit as seen from the line 4-4 of Fig. 1; FIG. 5 is a rear elevation of control valves mounted on the pump units, as seen from the line 5-5 of Fig. 1; FIG. 6 is a part section on plane 6-6 of Fig. 1; FIG. 7 is a part section on plane 7-7 of Fig. 4b; and FIG. 8 is an exploded view of the principal elements of the material housing seen in Fig. 1.

The pump of the present invention is particularly adapted for pumping moist granular building, for example plaster, concrete, or mortar. The pump will be described in conjunction with the pumping of concrete.

The concrete pump may be mounted to the rear of the cab of a motor vehicle or truck.

In such an application the power unit for the motor vehicle is employed as the primary power source for the concrete pump and is therefore provided with a drive member coupled between the power unit for the motor vehicle and the concrete pump. The power unit may be any other type of convenient unit when the pump is not mounted on a motor vehicle, such as an electric motor, for example.

The concrete pump generally comprises a pair of pumping units which are mounted on opposite sides of a material or concrete hopper. The hopper, as is conventional, is utilized to receive and store the concrete to be pumped and supplied thereto.

The pumping units are connected with a common material or concrete chamber for the pumps and are arranged in communication therewith and with the hopper to allow the pumping units to be directly charged with the concrete to be pumped from the hopper and to be discharged from the pumping units in response to their pmuping strokes through a common outlet for the concrete chamber. A conduit is normally coupled to the outlet for conveying the concrete to the point of utilization of the concrete. The concrete chamber is provided with a single control valve that is adapted to assume two positions and thereby subdivide the chamber into two portions for allowing the alternate charging and discharging of the concrete to occur substantially simultaneously in each portion of the chamber.

The two positions of the single control valve are effective for substantially closing off one of the pumping units from the hopper while allowing the same pumping unit to discharge concrete through the outlet.

During this same interval, the other pumping unit is substantially closed off from the discharge outlet while being in communication with the hopper through the hopper port.

The charging of a pumping unit results due to the drawing in of the concrete from the hopper as a result of the suction created by the pumping unit to be charged being retracted from its completed pumping stroke.

The control valve is positioned by a fluid pressure motor in a position to allow the pumping unit to discharge concrete through the discharge outlet while the other pumping unit is drawing concrete from the hopper.

The pumping units are constructed in the form of fluid pressure pumping units and preferably are hydraulically operated pistoncylinder units whereby the units are charged during their return strokes. The pumping units are controlled by a fluid power control circuit, preferably a hydraulic circuit, adapted to control the alternate charging and discharging of the concrete into and out of the pumping units while controlling the position of the control valve.

The above structure and operation is a summary of the concrete pump which is disclosed in the prior Patent No. 1,068,863 and is mentioned herein as a basis for simplifying explanation of the present invention.

Now specifically referring to the drawings, the general organization of the concrete pump 10 will be examined in detail. The pump 10 generally comprises a pair of pumping units A and B arranged with a concrete chamber housing C having a single valve control element or flapper element F rotatably mounted within the cylindrical concrete chamber CC. The concrete to be pumped is charged into the concrete chamber CC by means of the hopper H arranged in communication therewith. The sequencing of the pumping units A and B is controlled by means of the hydraulic drive means HDM.

The hydraulic drive means HDM functions with a pair of mechanically actuated valves shown as the cycle valve CV and the sequence make-up valve S. A storage tank ST for storing a lubricating or cooling medium, such as water, for the pumping units A and B is mounted between the units A and B as illustrated in Fig. 1.

The pumping units A and B are arranged in a parallel relationship with the concrete chamber housing C. The pumping units A and B each comprise reciprocating pistoncylinder assemblies controlled so that their forward or power strokes are utilized for pumping concrete through the housing C and their return, or suction strokes, are utilized to charge concrete into the pumping units. The pumping units A and B are both identically constructed and for the purposes of understanding the present invention only one of the units need be examined in detail. To this end, the pumping unit B is shown in detail in Figs. 4a and 4b. When the structure of Fig. 4a is aligned with the structure of Fig. 4b, the complete assembly of the pumping unit B will be appreciated. The pumping unit B comprises a material or concrete cylinder 12B having a reciprocating piston unit 13B mounted therein.The piston unit 13B comprises a piston head 13HB mounted at the end of the shaft 13 SB. The concrete cylinder 12B is closed at one end, the lefthand end as illustrated in Fig. 4B, and sealed by means of an "0" ring 12-OB for enclosing the cylinder. The shaft 13SB is arranged to reciprocate through the closed end of cylinder 12B. The remaining end of the material or concrete cylinder 12B is arranged in direct communication with the concrete chamber housing C in order to receive the concrete to be pumped in the cylinder 12B.The piston head 13HB is hydraulically controlled to reciprocate in a sliding re relationship with the concrete cylinder 12B for drawing in the concrete to be pumped from the hopper H through the concrete chamber housing C and then pumping it through the concrete chamber CC through outlet DO. When the piston head 13HB is being retracted during the suction stroke from the right-hand position towards the left end, or closed end, of the cylinder 12B, the concrete is drawn into the concrete -cylinder 12B in front of the piston head 13HB.

During the pumping strokes of the piston head 13H it travels from its left-hand end position I as illustrated in Fig. 4b to the right for pumping the concrete previously drawn into the cylinder 12B back through the concrete chamber CC and out through the discharge outlet.

From the above description, it should be appreciated that there is a closed volume defined behind the piston head 131113 when it is spaced from the closed end of the cylinder 12B. The closed volume is employed for receiving a lubricating and/or cooling medium behind the piston head 13HB as it reciprocates within the cylinder 12B, as will be explained more fully hereinafter. A push/pull rod assembly 14B is coupled to the piston head 13HB and is carried by the piston head. The red assembly 14B is mounted outside the pumping unit proper and is illustrated in Figs.

4a and 4b is mounted on the top of the pumping units A and B. The specific coupling of the push/pull rod assemblies 14A and 14B to the piston heads 13HA and 131113 is best appreciated from examining Fig. 4b. A push-pull rod 14B is mounted in a rod guide tube 15 secured adjacent the left-hand end of the concrete cylinder 12B as best appreciated from examining Fig. 7. The tube 15 mounts an override spring 16 seated be-tween a pair of spaced bushings 16A, 16B, and surrounding the tube-enclosed portion of the push/pull rod 14B; see Fig. 4a. The remaining end of the push/pull rod 14B is connected to a linkage assembly generally identified by the reference numeral 17B for operating one of the control valves associated with the hydraulic drive means HDM.

The push/pull rod 14B for the pumping unit B is specifically coupled to operate a cycle valve CV. The push/pull rod 14A for the pumping unit A is similarly coupled to a linkage 17A for operating a sequencing makeup oil valve S. The hydraulic drive means for the pumping units A and B is diagrammatically represented by a box HDM in Fig. 1 and is generally of the same construction as that disclosed in the said prior Patent No. 1,068,863. The hydraulic pressure provided by the drive means HDM is alternately applied to the two pumping units A and B so as to alternately power the corresponding piston heads 13HA and 13HB.

The hydraulic pressure is also alternately applied to the opposite ends of a hydraulic cylinder 20 mounted on the concrete chamber housing C for controlling the position of the single control element, or flapper element F, in accordance with the alternate pumping strokes of the pumping units A and B. The hydraulic drive means HDM alternately pressurizes the pumping units A and B to cause one of the piston heads 13HA or 13HB to move forward on a pumping or concrete discharge stroke, while the closed loop arrangement of the hydraulic circuit will cause the other pumping unit or piston head to move in the return or suction stroke for charging the pumping unit with concrete from the hopper H.The cycle of operation is controlled by the two push/pull rods 14A and 14B mounted with the pumping units A and B for operating the cycle valve CV and the sequence make-up oil valve S. The cycle valve CV when operated is effective for changing the position of the flapper element F and the valving (not shown) for reversing the direction of the pumping units A and B. The push/pull rod 14A for the pumping unit A actuates the valve S for automatically maintaining a constant volume of oil in the closed hydraulic circuit so as to assure a full stroke of the pistons 13HA and 13HB. This general type of operation is disclosed in the said prior Patent.

The efficiency of the hydraulic circuit HDM is increased over prior art hydraulic circuits such as disclosed in the said prior Patent by coupling the hydraulic fluid to act against the head side of the hydraulic pistons; see Fig. 4b. In the hydraulic circuit disclosed in the prior Patent the hydraulic pressure is developed to act on the rod side of the hydraulic piston, see Fig. 3 of the prior patent, for example. The present circuit arrangement results in more efficient operation since there are less hydraulic line losses.

In addition, certain costs are eliminated by operating with a very low hydraulic pressure on the rod side of the piston, namely, the elimination of the requirement for a high pressure seal between the hydraulic cylinder and the concrete cylinder.

The water tank ST is mounted between the parallel arrangement of the pumping units A and B with the concrete cylinders 12A and 1213. The water tank ST is specifically illustrated in Figs. 1 and 6 of the drawings.

The water tank ST is of a substantially L-shaped configuration and is arranged to be in direct communication with the lefthand end of the concrete cylinders 12A and 12B, as best appreciated from examining Fig.

1. The upstanding section of the L-shaped tank ST is provided with a cover 20'. The cover 20' is secured to the tank by means of a chain 21 fastened between the cover and a fastener, as best appreciated from examining Fig. 6. The tank includes means for draining the lubricating medium or water from the tank. The means for draining the tank ST, as illustrated in Fig. 6, is a manually operated stopper 22 in a drain aperture 22D in the bottom wall of the upstanding portion of the tank ST. The stopper 22 includes a handle 22H of an L-shaped configuration that is accessible through the tank opening when the cover 20' is removed to readily allow the water in the tank to be drained through the aperture 22D. It is necessary to have clear water in the cylinders to prevent damage to the pistons 13HA and 13HB.

Features of the present invention are the constructions of the concrete housing C and its coacting single control element or flapper element F. The concrete housing C is internally constructed and defined to mate with the configuration of the flapper element F so as to minimize any tendency for flow restriction of the material passing through the chamber CC. The construction of the concrete chamber CC and the flapper element F is best appreciated from examining Figs. 2, 3 and 8. The concrete housing C has a concrete chamber CC defined therein which houses the flapper element F. The flapper element F is consructed of one piece of material with coaxial trunnions FT arranged on opposite sides of the rectangular platelike element functioning as a flapper element.

The lower trunnion FT is rotatably mounted in the concrete housing C so as to mount the flapper or rectangular portion of the element F adjacent the bottom wall of the concrete chamber CC. The upper trunnion FT is similarly mounted.

The configuration of the element F for the above-mentioned purposes is produced by the contouring of the lateral faces of the rectangular plate-like element functioning as the flapper element F. Within a presselected area of the faces of the flapper element F a concavity is defined for mating with the cylindrical wall surfaces of the concrete chamber CC within the housing C. As best appreciated from examining Fig. 3, the con cave portion of the flapper element is in the form of a shallow C configuration. The contoured face 6f the flapper element F, when arranged with the adjacent surface of the cylindrical concrete chamber forms a conduitlike opening through the concrete housing for minimizing any tendency for restricting the material or concrete flow through the chamber CC.Since the flapper element F is constructed of one piece of material, it is easier to machine and thereby the concentricities can be more easily controlled than when several pieces have to be machined and assembled.

It should also be noted that the flapper element F is provided with corrosive resistant sleeves secured by welding to the trunnions FT. The sleeves are identified in Figs. 2 and 3 as sleeves FS illustrated in their assembled relationship with the concrete chamber C.

The sleeves FS are preferably constructed of a chrome-plated material for anti-corrosion purposes. In addition, the outer ends of the flapper element F are tapered and provided with a hard facing overlay for the complete lateral extent thereof for providing shearing edges for the flapper element. The hard facing overlay is illustrated in Fig. 2 and is identified as the respective portions FOV on the opposite ends of the flapper element F.

The flapper element F and the concrete chamber housing C are also provided with wear means for minimizing the wear on the flapper element F and the housing C per se.

The wear means comprises wear plates WP in the form of discs, one of which is mounted on the bottom surfaces of the cylindrical concrete chamber CC within the housing C.

A similar wear plate WP is mounted to the top side of the cylindrical chamber as shown in Figs. 2 and 3. The concrete housing C is provided with a large cover CC' that is secured to the top thereof by fasteners 22 and is therefore readily removable. The large opening provided upon the removal of the cover CC' permits the interior of the housing C to be readily machined for providing a smooth surface. As a result, the accuracy with which the interior surfaces of the housing C can be defined is closely controlled. This permits the wear plate WP to be easily mounted and assembled in the desired relationship on the bottom surface of the concrete chamber CC. On prior art structures, machining was so difficult to accomplish that the wear plates were mounted on uneven cast surfaces and had to be shimmed to provide even surfaces.The shimming was by means of a putty-like material which required a high degree of skill to accomplish.

The remaining wear plate WP is advantageously secured to the inside surface of the cover CC'; see Figs. 2 and 3. A portion of the upper trunnion FT extends out of the cover CC' to allow it to be coupled to the cylinder 20 for rotating the flapper element F between its two positions. The cylinder 20 is shown in Fig. 1 mounted on the top surface of the concrete chamber and is readily accessible. The concrete chamber CC is also provided with a plurality of wear pins WPI secured in the housing C at the four locations that the edges of the flapper element F move into sliding engagement therewith; see Figs. 1 and 8.

For the purposes of cleaning out the housing C, a pair of doors CD, one of which is illustrated in Fig. 8, permit access to the interior of the housing C on opposite sides of the flapper element F. The door CD is secured to the door opening CDO by means of a seal CDS. This allows any residual concrete left in the housing C after completion of the pumping operation to be readily cleaned out from both sides of the flapper element F. With the removal of the doors CD, a tool may be inserted into the openings CDO to scrape out the concrete residue.

Other features of the apparatus described above are claimed in our divisional applications Nos. 44660/79 and 44661/79 (Serial Nos.

1,600,466 and 1,600,467).

WHAT WE CLAIM IS: 1. Apparatus for pumping a moist granular building material for example plaster, con crete, or mortar, and including: first and second pumping units; a housing having a material inlet and a material outlet arranged on opposite sides of an internal, cylindrical chamber defined. in the housing, the housing also having means connecting the chamber with the pumping units; means for charging the chamber through the inlet with the material to be pumped;; a plate-like control member swingably mounted in the chamber to divide it into two oscillating portions and allowing the portions to conduct the material from the inlet to one of the pumping units by way of the connecting means and simultaneously to conduct the material from the other pumping unit to the outlet by way of the connecting means, the control member having lateral faces and a pair of trunnions extending in opposite directions parallel with the lateral faces, the control member swinging about the trunnion axes and being in one piece, each lateral face having a concave area for mating with the adjacent arcuate wall surface of the chamber for reducing the flow restriction of the material conveyed through the chamber; and automatic means for operating the pumping units and for swinging the control member in preselecting timed relationship therewith.

2. Apparatus according to claim 1 wherein the pumping units are arranged with their axes parallel and each has a piston head mounted in a material cylinder having spaced ends so as to be reciprocated from one end of the cylinder to the opposite end thereof, one end. of each cylinder being in communication with the chamber for receiving

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. for minimizing any tendency for restricting the material or concrete flow through the chamber CC. Since the flapper element F is constructed of one piece of material, it is easier to machine and thereby the concentricities can be more easily controlled than when several pieces have to be machined and assembled. It should also be noted that the flapper element F is provided with corrosive resistant sleeves secured by welding to the trunnions FT. The sleeves are identified in Figs. 2 and 3 as sleeves FS illustrated in their assembled relationship with the concrete chamber C. The sleeves FS are preferably constructed of a chrome-plated material for anti-corrosion purposes. In addition, the outer ends of the flapper element F are tapered and provided with a hard facing overlay for the complete lateral extent thereof for providing shearing edges for the flapper element. The hard facing overlay is illustrated in Fig. 2 and is identified as the respective portions FOV on the opposite ends of the flapper element F. The flapper element F and the concrete chamber housing C are also provided with wear means for minimizing the wear on the flapper element F and the housing C per se. The wear means comprises wear plates WP in the form of discs, one of which is mounted on the bottom surfaces of the cylindrical concrete chamber CC within the housing C. A similar wear plate WP is mounted to the top side of the cylindrical chamber as shown in Figs. 2 and 3. The concrete housing C is provided with a large cover CC' that is secured to the top thereof by fasteners 22 and is therefore readily removable. The large opening provided upon the removal of the cover CC' permits the interior of the housing C to be readily machined for providing a smooth surface. As a result, the accuracy with which the interior surfaces of the housing C can be defined is closely controlled. This permits the wear plate WP to be easily mounted and assembled in the desired relationship on the bottom surface of the concrete chamber CC. On prior art structures, machining was so difficult to accomplish that the wear plates were mounted on uneven cast surfaces and had to be shimmed to provide even surfaces.The shimming was by means of a putty-like material which required a high degree of skill to accomplish. The remaining wear plate WP is advantageously secured to the inside surface of the cover CC'; see Figs. 2 and 3. A portion of the upper trunnion FT extends out of the cover CC' to allow it to be coupled to the cylinder 20 for rotating the flapper element F between its two positions. The cylinder 20 is shown in Fig. 1 mounted on the top surface of the concrete chamber and is readily accessible. The concrete chamber CC is also provided with a plurality of wear pins WPI secured in the housing C at the four locations that the edges of the flapper element F move into sliding engagement therewith; see Figs. 1 and 8. For the purposes of cleaning out the housing C, a pair of doors CD, one of which is illustrated in Fig. 8, permit access to the interior of the housing C on opposite sides of the flapper element F. The door CD is secured to the door opening CDO by means of a seal CDS. This allows any residual concrete left in the housing C after completion of the pumping operation to be readily cleaned out from both sides of the flapper element F. With the removal of the doors CD, a tool may be inserted into the openings CDO to scrape out the concrete residue. Other features of the apparatus described above are claimed in our divisional applications Nos. 44660/79 and 44661/79 (Serial Nos. 1,600,466 and 1,600,467). WHAT WE CLAIM IS:

1. Apparatus for pumping a moist granular building material for example plaster, con crete, or mortar, and including: first and second pumping units; a housing having a material inlet and a material outlet arranged on opposite sides of an internal, cylindrical chamber defined. in the housing, the housing also having means connecting the chamber with the pumping units; means for charging the chamber through the inlet with the material to be pumped;; a plate-like control member swingably mounted in the chamber to divide it into two oscillating portions and allowing the portions to conduct the material from the inlet to one of the pumping units by way of the connecting means and simultaneously to conduct the material from the other pumping unit to the outlet by way of the connecting means, the control member having lateral faces and a pair of trunnions extending in opposite directions parallel with the lateral faces, the control member swinging about the trunnion axes and being in one piece, each lateral face having a concave area for mating with the adjacent arcuate wall surface of the chamber for reducing the flow restriction of the material conveyed through the chamber; and automatic means for operating the pumping units and for swinging the control member in preselecting timed relationship therewith.

the material to be pumped therein and the opposite ends of each cylinder being closed, each piston end defining a closed, variable volume between the closed end and one end of the piston head in accordance with the position of the piston head in the material cylinder, and a lubricating medium storage tank being mounted between the pumping units so as to be directly coupled in communication with the closed ends of each cylinder for permitting stored lubricating medium to flow into and out of the said closed volumes behind the piston heads in accordance with their respective positions.

3. Apparatus according to claim 2 wherein the lubricating medium is water.

4. Apparatus according to any preceding claim wherein each pumping unit is a hydraulically powered piston and cylinder unit and includes fluid pressure control circuit means for alternately pressurizing the pistons on a pumping stroke, the circuit means coupling the hydraulic fluid so as to act against the head side of the piston units.

5. Apparatus for pumping a moist granular building material, for example plaster, concrete, or mortar, and including: first and second pumping units; a material housing having a substantially cylindrical chamber internally thereof, the housing including a material inlet and a material outlet communicating with the chamber, the housing also having means connecting the chamber with the pumping units; means for charging the chamber with the material to be pumped through the inlet;; a valve element rotatably mounted within the chamber and extending into sliding engagement with the chamber wall for controlling flow of material at the inlet and the outlet so as to divide the chamber for alternately allowing the divided portions to function with the pumping units as a means to charge the material therein and to discharge the material therefrom, the valve element being arranged in the chamber relative to the inlet and the outlet so as to isolate the portion of the chamber discharging material from communication with the charging means but in communication with the outlet, the valve element being a blade element having aligned trunnions and being rotatably mounted thereby and having oppositely contoured concave faces for mating with the opposed arcuate walls of the chamber for reducing flow restriction of the material conveyed through the chamber; and automatic means for operating the pumping units and for changing the position of the valve element in preselected timed relationship therewith.

6. Apparatus according to any preceding claim, wherein the housing has a removable cover for exposing the control member or valve element which is removable from the housing when the cover is removed.

7. Apparatus according to any preceding claim, wherein the housing includes wear means on which the control member or valve element rotates.

8. Apparatus according to claim 7, wherein the wear means comprises a wear plate secured to the side of the housing opposite the cover and a wear plate secured to the chamber side of the cover.

9. Apparatus according to any preceding claim including a lubricating medium storage means for the pumping units for direct coupling with the pumping units.

10. Apparatus according to claim 9 having a lubricaring water storage tank mounted between the pumping units so as to be directly coupled in communication with the closed ends of respective cylinders of the pumping units for permitting the stored lubricating water to flow directly into the respective cylinders for filling the volumes defined behind each respective piston head of the pumping units and to be moved back into the tank by the piston heads without requiring an additional power source therefor.

11. Apparatus according to claim 10 including means for draining the water from the tank.

12. Apparatus according to claim 11 including a removable cover for the tank.

13. Apparatus according to claim 12 wherein the drainage means includes a drain stopper accessible from the top of the tank.

14. Apparatus according to claim 5, wherein i) the pumping units are hydraulically operated and controlled pumping units and include hydraulic drive means for alternately placing them in a pumping stroke and a return stroke; ii) the pumping units comprise pistoncylinder units in which the pistons are reciprocable between a pumping stroke and a return stroke in response to the hydraulic drive means; iii) push-pull rod means is mounted on the outside of each pumping unit and coupled to an individual piston to be reciprocated thereby, the push-pull rod means being coupled to the hydraulic drive means for controlling the cycle of operation of the pumping units.

15. Apparatus according to claim 14, wherein each rod means is coupled to an individaul valve element for mechanically operating the valve in accordance with the positions of the rod coupled thereto.

16. Apparatus according to claim 1 or claim 5 wherein the automatic means for operating the pumping units comprises hydraulic drive means and each pumping unit comprises a material cylinder in communication with the material chamber and a piston head mounted in the material cylinder to be reciprocated from one end of the individual cylinder to the opposite end thereof in response to the hydraulic drive means which is coupled to the head sides of each piston head.

17. Apparatus according to claim 8, wherein the wear means includes wear pins secured in the cylindrical chamber at four locations, the control member or valve element slidably engaging the chamber wall.

18. Apparatus according to claim 5, wherein the valve element comprises a substantially rectangular blade element having the aligned trunnions extending outwardly from opposite longitudinal edges thereof and each arranged substantially centrally of the longitudinal edges and coaxial with one another as a one-piece valve element, the blade element having a concavity of preselected depth within a preselected perimeter of each lateral face thereof.

19. Apparatus according to claim 18, wherein the tips of the blade element each have a hard face overlay thereon for the complete extent, and are tapered for providing shearing edges.

20. Apparatus according to claim 18, wherein the trunnions have corrosion-resistant sleeves secured thereto extending outwardly from the longitudinal edges of the blade element a preselected distance.

21. Apparatus according to claim 20, wherein the sleeves are chromium plated.

22. Apparatus for pumping a moist granular building material, constructed and arranged substantially as herein described and shown in the drawings.