Abstract: The invention relates to a method for operating a piston pump with a differential cylinder drive (1) with at least two differential cylinders (2, 3) for driving at least two conveying pistons movable in conveying cylinders, each conveying piston being driven via an associated differential cylinder (2, 3) of the differential cylinder drive (1) for operating the piston pump, with a hydraulic circuit (4) for driving the differential cylinder drive (1) by the action of hydraulic fluid. The invention also relates to a piston pump for carrying out the method.

Abstract: A radial piston pump has a plurality of cylinders within which pistons reciprocally move. Each cylinder is connected to a first port by an inlet passage that has an inlet check valve, and is connected to a second port by an outlet passage that has an outlet check valve. A throttling plate extends across the inlet passages and has a separate aperture associated with each inlet passage. Rotation of the throttling plate varies the degree of alignment of each aperture with the associated inlet passage, thereby forming variable orifices for altering displacement of the pump. Uniquely shaped apertures specifically affect the rate at which the variable orifices close with throttle plate movement, so that the closure rate decreases with increased closure of the variable orifices.

Abstract: A concrete pump system/method configured to provide substantially constant flow of concrete or cement material is disclosed. The system integrates a trapezoidal cutting ring and spectacle plate in conjunction with lofted transitional interfaces to the hydraulic pump cylinder rams and output ejection port to ensure that pressurized discharge concrete material is not allowed to be relaxed nor backflow into the material sourcing hopper. The trapezoidal cutting ring is configured to completely seal off the trapezoidal spectacle ports as it smoothly transitions between the hydraulic pump input ports during cycle changes thus generating a more uniform output flow of concrete while eliminating hopper backflow and hydraulic fluid shock. A control system is configured to coordinate operation of the hydraulic pump cylinder rams and cutting ring to ensure that output ejection port pressure and material flow is maintained at a relatively constant level throughout all portions of the pumping cycle.

Abstract: A fluid rotary machine with a decreased footprint and a reduction in the number of parts. The fluid rotary machine has four heads wherein double-headed pistons are disposed inside cylinders in a crisscross arrangement. The rotational balance between rotational parts including the double-headed pistons is achieved only by first and second balance weights which are inserted and incorporated into both ends of a crank shaft coupled eccentrically to a shaft. The shaft is rotated for the double-headed pistons to linearly reciprocate in the cylinders. The fluid rotary machine has rotary valves for switching between the suction and discharge operations of the fluid for each cylinder chamber. The rotary valves are incorporated into a case to be coaxial and integrally rotatable with the shaft.

Abstract: A Concrete Pump is a mechanical device comprising of a round funnel shape hoper, pump outlet, rotating pressure and wear plates. Attached to the rotating pressure and wear plates are rotating pump cylinders and opposite the pump cylinders are a rotating wear plate. Pressed against the rotating wear plates is the stationary wear. A hoper outlet and a pump outlet flange are attached to the stationary wear plate. The pump functions as follows: concrete from the hoper passes through the stationary and rotating wear plates into one pump cylinder, at the same time, concrete from another cylinder (previously field with concrete) is pushed through the rotating wear plate and through the stationary wear plate into the pump's outlet. When the pistons reach the end of the cylinders the rotating wear plates and concrete cylinders rotate by 180 degrees and the process is repeated again. The pump is designed so that an entire volume of concrete or similar pumping substance is pumped out of the hoper.

Abstract: Embodiments of the present invention are directed to devices and methods for propelling fluids that feature at least one first pump assembly having a primary pump, an accumulator pump, drive means, valve means and control means. The valve means moves between the first position and the second position as the accumulator pump and primary pump alternate between a loading movement and a pump movement. The control means is in signal communication with the accumulator pump, the primary pump and the valve means. The control means issues signal command to the accumulator pump to assume the loading movement and the pump movement and the primary pump to assume the loading movement and pump movement in coordination with the movement of the valve means such that fluids are propelled from the first outlet.

Abstract: The present invention relates to a compressor, which includes a main refrigerant supply channel for supplying refrigerant by passing through the inside of a driving shaft and an auxiliary refrigerant supply channel for supplying refrigerant by passing through a suction chamber of front and rear housings and a slot of the driving shaft after passing through cylinder blocks in order to supply the refrigerant inhaled into a swash plate chamber to cylinder bores, thereby enhancing performance and lubricating ability of a driving shaft seal area since the refrigerant of the swash plate chamber can be used effectively.

Abstract: In a two-cylinder slurry pump for the continuous feeding of, in particular, concrete, in which pump two feed cylinders remove the high-viscosity material from a pre-charging tank and deliver it to a feed line, a diverter valve is provided with a cross-section that narrows from an inlet opening assigned to the cylinders to a discharge opening assigned to the feed line, which diverter valve connects, in any position, at least one feed cylinder, over its entire cross-section, to the feed line, a support arrangement (20) and a plate cam (15) securely connected thereto being assigned in accordance with the invention to the diverter valve (11) on its side facing towards the cylinders (3, 5). The plate cam (15) comprises not only the inlet opening (21) of the diverter valve (11) but also an intake opening (23), which is arranged at sufficient distance from the inlet opening (21) to cover an opening of one of the feed cylinders (3, 5) completely.

Abstract: The invention relates to a device and a method for controlling a two-cylinder thick matter pump comprising delivery pistons that are actuated in a push-pull manner by means of a hydraulic reversible pump (6) and hydraulic drive cylinders controlled by said pump. For each pressure stroke, the delivery cylinders (50, 50?) are connected to a delivery conduit (58) by means of a pipe junction (56). At the end of a pressure stroke, a reversal process of the reversible pump (6) and the pipe junction (56) is triggered. The aim of the invention is to obtain a targeted reversal of the reversal pump and the pipe junction, even when the deliverable quantity is varied, whereby the delivery cylinders are completely emptied, but also without pistons banging the ends of the cylinders.

Abstract: There are a number of applications today where the pumping of abrasive slurries is necessary. The pumping mechanisms, though, can be complex, employing multiple transfer cylinders and movable pipes. These designs have their problems, specifically wear between poorly sealing surfaces. To reduce this problem, seals are provided that have multiple wear surfaces which include harder tiles secured over a softer core to benefit from the relative hardness or flexibility of each of the respective materials.

Abstract: A concrete pump with a pivoting valve and hopper assembly is provided with a novel wear plate and wear ring. The wear plate is mounted on the frame of the pump and remains mounted on the frame as the valve and hopper assembly pivots between open and closed positions. When the valve and hopper assembly is open, the wear plate is accessible for examination and replacement. The hopper is provided with an opening through which the wear plate extends when the valve and hopper assembly is closed. A seal on the hopper around the opening sealingly engages the frame. A wear ring on the valve engages the wear plate when the valve and hopper assembly is closed. A cam plate on each side of the frame is engageable with the valve and hopper assembly as the assembly pivots to a closed position to ensure alignment between the valve and hopper assembly and the frame.

Abstract: A double-headed piston type compressor connected with an external device is provided. The compressor includes a plurality of cylinder bore pairs, double-headed pistons, a first rotary valve, a second rotary valve, first suction passages, and second suction passages. In each cylinder bore pair, a first time period from a first top dead center timing, which is timing when the double-headed piston reaches a top dead center in a first compression chamber, to a first communication start timing, which is timing when a first introduction passage starts to communicate with a first suction passage, is different from a second time period from a second top dead center timing, which is timing when the double-headed piston reaches a top dead center in a second compression chamber, to a second communication start timing, which is timing when the second introduction passage starts to communicate with a second suction passages.

Abstract: A dual cylinder positive displacement pump is used to move drill cuttings. The pump may include one or more of a self-sealing wear ring member/wear plate member interface, stainless steel pumping cylinders, and a hopper with an inclined surface.

Abstract: A method for controlling a thick matter pump comprising two delivery cylinders (10) emerging, via two openings (12), into a material reservoir (14), associated with two delivery pistons (26), symmetrically synchronized relative to said cylinders, and a branch pipe 18 arranged inside the material reservoir (14), capable of being connected, on the input side, alternatively to one of the openings of the delivery cylinders with exposing of the other opening, the output side connected to a conveyance conduit (20). When the pumping is interrupted, thick matter, liquid concrete for example, is sucked up, via the delivery cylinder temporarily communicating with the reservoir, and is delivered, via the other cylinder (10), connected to the branch pipe (18), so as to form a column of thick matter through the delivery pipe (20), towards its output.

Abstract: A concrete pump includes a hopper having a plate with a pair of openings and an S-tube valve assembly which is movable between the two openings. The valve assembly includes an S-tube which is connected to a mounting plate which is pivotally mounted on the hopper. A wear ring is movably supported within an opening in the valve assembly and engages the hopper plate. A retainer ring is positioned within the opening of the valve assembly and engages a flange on the valve assembly. A resilient spring is positioned between the wear ring and the retainer ring and resiliently urges the wear ring against the hopper plate.

Abstract: A two-cylinder thick-matter pump for continuous delivery of thick matter is characterized in that a reversing valve (5) has a diverter housing (8, 8′) with at least four openings (a-b), the diverter (6, 6′) disposed in the diverter housing (8, 8′) is swiveled with its outlet opening in front of the cylinder openings and has an inlet opening (RE) which is firmly connected with the suction pipe (3), the cavity (H) in the diverter housing (8, 8′) being constantly under delivery pressure, and at least one shut-off element (10) being provided for closing the suction pipe (3) and/or the first and/or second openings (a , b) of the diverter housing (8, 8′).

Abstract: An energy recovery device includes at least one cylinder, a piston slidable in the cylinder, a first valve for selectively connecting one end of the cylinder to waste liquid at a first relatively high pressure and to drain and a second valve for allowing feed liquid to enter the other end of the cylinder at a second lower pressure via a feed liquid entry port and to be discharged via a feed liquid discharge port from the other end of the cylinder in response to movement of the piston caused by waste liquid entering the one end of the cylinder. A rod which extends from the other end of the cylinder and into but not through the piston, ensures that the area of the piston acting on the feed liquid is less than the area of the piston acted upon by the waste liquid so that the piston acts as a pressure intensifier to discharge feed liquid through the feed liquid discharge port at a higher pressure than the pressure of waste liquid entering the one end of the cylinder.

Abstract: A shuttle valve for use in a pumping apparatus for pumping concrete or the like. The valve uses belleville springs to hold a wear ring against the concrete hopper, thereby creating a seal.

Abstract: The present invention relates to a pipe switch for a dual-cylinder thick-liquid pump, wherein said system comprises a pivoting pivot pipe (36) located in the front of a glasses-like wear plate (34) on the cylinder side as well as a wear ring (38) which is capable of limited axial displacement at the end of the pivot pipe (36) on the cylinder side. The ring can be pressed against the wear plate (34) by the hydrostatic pressure existing inside said pivot pipe. The wear ring 38 has a centering portion (46) guided on an axis-parallel centering surface (42) of the pivot pipe (36) as well as a sealing part (54) resting against the wear plate (34) through an abutment surface (52) on the cylinder side. The pivot pipe (36) and the sealing part (54) of the wear ring (38) have annular surfaces (56, 58) which face each other and which are axially spaced from one another by an annular gap (59) opened towards the inside of the pipe.

Abstract: A head cover assembly for a compressor according to the present invention includes a valve plate mounted onto the compressor cylinder having a first side, a second side, a first bore, and a second bore, a first valve connected to the first side of the plate for controlling flow through the first bore, and a second valve connected to the second side of the plate for controlling flow through the second bore. The first and second valves are attached substantially adjacent the center of the plate using a single fastener. A cover is mounted onto the second side of the valve plate. The cover includes a continuous side wall which surrounds the first and second bores, an enclosure wall extending between the top edge of the side wall thereby enclosing a volume above the valve plate, and a divider wall which extends between the side wall through the enclosed volume to define an intake volume and an exhaust volume.

Abstract: Pump to supply fluid to at least two circuits in a control system for a production well. Each of the circuits is maintained at different pressures. The pump provides fluid to a plurality of poppets that are opened or closed depending on the positions of a cam surface which controls the position of the poppet. A pressure relief valve is used to prohibit fluid from entering a circuit unless the pressure exceeds the pressure of the fluid in the control circuit. The cam surfaces are controlled by a knob rotatable by an operator. By rotating the knob, the poppets can be opened or closed so as to provide fluid sequentially to each of the circuits and pressurize each circuit individually.

Abstract: A apparatus for feeding concrete and other thick materials from a container into a feeding pipe by two feeding cylinders which are alternately connectable by a switching device to the container or the feeding pipe. The feeding pistons of the feeding cylinders alternately perform a suction stroke and a pressure stroke, with the average piston speed being at least temporarily greater during the suction stroke than during the pressure stroke. A continuous feeding flow is achieved in that during the switching period t.sub.u of the switching device the two feeding cylinders are substantially separated from the container at least temporarily and are short-circuited together to form a joint conenction with the feeding pipe. In this state, the one feeding piston is still finishing its pressure stroke while the other feeding piston already begins its pressure stroke at the same time.

Abstract: A mechanism for pumping slurry includes a housing for receiving the slurry and two cylinders secured to the housing for drawing the slurry into and out of cylinders. A pipe is pivotally secured to the housing and has one end for selectively aligning with either of the openings and for allowing the slurry to be supplied into the pipe by the cylinders alternatively. The housing includes a pivotal follower for rotating the pipe and one or more actuators for rotating the follower and the pipe.

Abstract: A pump valve assembly includes a pair of pistons containing cylinder bores opening to a front wall for conveying a concrete mixture from a feed chamber to a delivery tube. A pivotal S-bend tube establishes fluid communication between two valve body wear rings and the delivery tube to cause a translational movement of the input port to the valve assembly between two operative positions in which the input port is in register with the wear rings, the S-bend tube also being engaged with a wear ring. During use, compression of the valve assembly against a positive displacement pump is achieved solely at the front wall of the assembly, with the delivery tube at the rear wall providing only alignment and support, thereby enabling rapid disassembly and access to the valve body and S-bend wear rings.

Abstract: In order to reduce the overall size of serial pump arrangements, several block-disk-like building elements are used. These building elements are made of a non-metallic material and lie against each other with their control surfaces in a sandwich like stack. Two of the block-disk-like building elements have displacement chambers oriented transversely to the axis of the stack, in each of which is guided a push piston. Inflow and outflow bores in which the high pressure mass flow, for example a chemical buffer, is created, extend parallel to the stack axis. Both building elements form two serially arranged pumping units of the serial pump arrangement and ensure a constant and continuous mass flow. Check valves are provided at the suction and delivery sides of both pumping units. Besides saving space, this arrangement ensures a highly constant and continuous mass flow, as the throughflow paths are as short as possible.

Abstract: A valveless positive displacement pump having pistons that undergo both rotating and reciprocating motion. The assembly comprises a radially outer, ported first cylinder with an axially outer, closed off end, a radially intermediate combination element having outer surfaces serving as a first piston relative to the main cylinder and inner surfaces defining a cylinder for a second piston. The pistons are concentrically arranged, and each reciprocates and rotates within its own cylinder. The piston part of the intermediate element includes a first chordwise relief adjacent its axially inner end and a second chordwise relief in the middle of its shank portion. An access port extends through a wall of the second relief into the interior of the second element. The axially outer ends of first and second pistons each include means for connection to a drive unit with a rotational axis that intersects but is offset from the rotational and reciprocating pistons.

Abstract: In a pump for thick matter with delivery cylinders (1, 2), in particular a two-cylinder concrete pump, which in order to control the flow of thick matter, incorporates a distributing regulator (11) that is connected permanently at an outlet opening (8) with the pump-side end (9) of a delivery line (7) and which incorporates at least one inlet opening (12) where it is sealed on the web (29) between the thick-matter flow passage openings (16, 17) from the delivery cylinders into a supply tank (6), the thick-matter flow passage openings (16, 17) and the inlet opening (12) of the distributing regulator (11) being of identical outline and area, the distributing regulator (11) connecting adjacent thick matter flow passage openings (16, 17) alternately with the delivery line (7) and the supply tank (6) by a rotating movement, the present invention provides for the fact that the thick-matter flow passage openings (16, 17) together with their associated delivery cylinder openings (22, 23) are each connected through a

Abstract: A method of pumping a product by means of a dosing pump unit entails that two individually driven pump chambers, which are connected with a common outlet, are controlled in such a way that the suction phases of the pump chambers overlap each other so that the total inflow to the pump unit is maintained constant. A pump unit includes two pump chambers which have a common inlet and outlet. Communication between the pump chambers and the inlet and outlet is controlled by a valve body, having an inlet passage that is formed such that it can be oriented to connect both pump chambers with the inlet.

Abstract: A tube switch for a double-cylinder sludge pump is provided including a swing pipe, a wearing ring and an elastic member. The swing pipe is adapted to swivel in front of a center plate and includes an extension portion having an inner surface. The wearing ring is supported between the end of the swing pipe and the center plate and is axially movable relative to the swing pipe. The wearing ring has a recess formed at one end thereof, defined by a sloped boundary surface. The swing pipe is adapted to receive the end of the wearing ring including the recess therein. The recess thus defines an annular space between the swing pipe and the wearing ring with the inner surface of the extension portion of the swing pipe facing the annular space. The elastic member includes a radial inner surface and a sloped front end surface that corresponds to the boundary surface of the wearing ring. The elastic member is supported between the swing pipe and the wearing ring within the annular space.

Abstract: A material-feeding container is disclosed for two-cylinder thick-matter pumps having feeding cylinders that open into the container. Inside the container is arranged a switchable guide-tube linked to the feeding line and alternatively movable between the openings of the feeding cylinders. A cleaning and servicing opening that can be closed with a cap provided with an agitator is arranged in each side wall. When the closing cap hinged on the material-feeding container is opened, the agitator pivots out of the container through the servicing opening, making the switchable guide-tube and its wearing parts freely accessible from the outside.

Abstract: An improved pumping device for delicate or easily damaged products is provided with a hopper, or other system for holding the products, and at least one, and preferably two, synchronized piston pumps positioned proximate to the bottom of the hopper. The piston pumps displace the product from the interior of the hopper into a consolidating feed manifold where the product is then dispensed through a discharge conduit into suitable receptacles. Each of the piston pumps preferably includes a pump cylinder with a fixed, elongated, cylindrical sleeve housing and an elongated rotatable cylindrical sleeve positioned within the sleeve housing, both enclosing a piston chamber. A first longitudinal opening or access port is formed in the fixed sleeve housing and a corresponding second longitudinal opening or access portion is formed in the rotatable sleeve.

Abstract: A multi-cylinder piston pump of rotary slide valve design for conveying free flowing materials, in particular concrete, comprises a rotary slide valve (33, 36) connected to the piston (48, 49) and their cylinders (44, 45) with which it pivots. The feeder hopper (4) of the pump is equipped with a stirrer (5) which is actuated only when the pump is in operation. The rotary slide valve (33, 36) is located outside the feeder hopper (4). During the delivery stroke, the axis of the delivery cylinder is coaxial with the longitudinal axis of the adjacent conical pressure pipe (18). This pump is of simpler design than known pumps and is therefore more reliable and requires less maintenance.

Abstract: A two-cylinder pump for heavy flowable material comprising a pump body with a deck surface, a pair of cylinder bores opening at the deck surface, and a piston reciprocating in each cylinder bore in charging and discharging strokes. The pump further includes a valve conduit with an inlet port for the transfer of flowable material between the valve conduit and the cylinder bores, the valve conduit being pivotable about an axis to cause a movement of the inlet port across the deck surface between two operative positions, in each operative position the inlet port being in register with either one of the cylinder bores. A fluid operated piston-cylinder assembly is operatively mounted between the valve conduit and the pump body in order to produce a force with a direction generally coincident with the pivotal axis on the valve conduit for urging the inlet port thereof in sealing engagement with the deck surface of the pump body.

Abstract: In a two-cylinder viscous liquid pump with a pipe switch, which by means of a swing pipe alternately connects one of the pump cylinders with the conveyor pipe and releases the other pump cylinder, and which swing pipe is moved along its path of travel by a sliding pin drive via a rocking shaft at varying speeds, powered by one or more hydraulic cylinders, the invention provides a link in the transmission of motion from the drive output to the sliding pin drive, which link serves to change the distance of the connecting element of the sliding pin drive to the axis of the rocking shaft, going from a maximum distance at the beginning and end of the link travel to a minimum distance at the center of the link travel.

Abstract: A metering pump including adjacent valve and pump chambers, the valve chamber having inlet and outlet connections and a valve plug angularly shiftable in the valve chamber to communicate said connections with opposite sides of the plug upon angular shifting of the plug, and a reciprocatory piston in the pump chamber, there being fluid communication between opposite ends of the pump chamber and the valve chamber on opposite sides of the valve plug, so that piston reciprocation in both directions moves fluid in the inlet connection and out the outlet connection upon shifting of the valve plug.

Abstract: In positive displacement pumps using double pistons for the alternating supply of pasteous material from two supply cylinders through a pivotable feed tube arranged in a feed chamber spaced at a radial distance from a controllably positionable shaft, the supply end of the feed tube is subjected to wear, which can impair the seal of the pump, and result in bleeding off of the pasteous material. In the inventive pump the supply conduit is connected to the pivotable feed tube through a pivotably arranged connecting member, through which adjustment of a sealing ring disposed in a rear wall of the feed chamber, and abutting a ring-shaped and also easily replaceable wear-resistant ring-shaped member is facilitated, while also permitting easy replacement of the sealing ring.

Abstract: The invention relates to a device for sealing in the zone of contact between the mouths of alternately charging and discharging delivery cylinders of a concrete pump and a swinging pipe that is alternately movable to alignment in front of the cylinder that is discharging at the time. It comprises an annular seal body so supported at the mouth zone of the delivery cylinder as to be slidable between a sealing position projecting into the rear end portion of the swinging pipe and a withdrawn releasing position in which it is spaced from the swinging pipe so as not to interfere with its swinging. The seal body is maintained in its withdrawn position whenever the swinging pipe is moving, thus substantially avoiding abrasion.

Abstract: A pumping system for various flowables utilizes a dual alternating piston pump in communication with a tank hopper having flowable material inlet and delivery lines and an internal oscillating elbow conduit equipped with a pressurized wear plate which is moved cyclically into and out of registration with the cylinders of the dual alternating piston pump. A vacuum pipe rising from the tank hopper having a floating check valve and a suction shut off valve communicates with a vacuum pump external to the tank hopper through a filter. The evacuated tank hopper is enabled to fill itself immediately with flowable material and maintain a full condition while the dual alternating piston pump is pumping material through the delivery line with high efficiency. When vacuum to the tank hopper is shut off, the dual piston pump can be reversed to pump through the suction line while drawing in material through the delivery line.

Abstract: A slurry pump having a pair of cylinders aligned one on either side of a centrally-disposed oscillating-deflector element; each cylinder has a housing in which are defined co-axial, registering hydraulic and slurry cylinder bores, and a piston rod having, at one end thereof a hydraulic piston head slidably movable within the hydraulic cylinder bore and having, at its other end a slurry piston head slidably movable within the slurry cylinder bore.

Abstract: A slurry pump has a hopper containing slurry. A pumping cylinder containing a piston communicates with the hopper through the hopper wall. A delivery tube is swung into and out of register with the cylinder. Slurry is drawn into the cylinder by the piston and out through the delivery tube. The pump is controlled by a lever which has a central neutral position and two operating positions.Dangerous moving parts are covered by a guard mounted on hinges. An arm on the guard engages a slide which has a channel. If the guard is moved from its closed position, the arm slides the slide so that the control lever enters the channel and moves to its neutral position. The external moving parts include releasable clamping means for sealing the junction of the delivery tube and the cylinder while slurry is being transferred from the cylinder to the tube.

Abstract: A concrete pump comprises a water rinsing box, a valve housing and a pair of concrete pump cylinders there-between. The rinsing box and the valve housing are welded at opposite ends of rigid connecting means such forming a rigid undetachable structure in which the cylinders are removably fastened and can be drawn out through the valve housing after removal of a housing closure flap.

Abstract: A twin cylinder pump for viscous materials such as concrete, having a guide for a cutting ring producing a sealing effect on the cylinder and a seat for supporting a loaded spring ring of elastic material of rubber or the like, is so designed that the ring is acted upon by the pressure of the feed taking effect in the ring-like gap, open as far as supporting face or seat of the spring, between the cutting ring and the valve member. Furthermore there is a guiding and constraining means for the ring taking effect thereon between the radial faces against which it is rested.

Abstract: An apparatus for oscillating a distribution duct between two outlets of adjacent pump cylinders and a common discharge pipe. A portion of the apparatus pivots with the discharge pipe and cooperates with a stationary housing to relieve thrust loads imparted during the pumping operation. A movable hopper is employed to feed material to the pumps and facilitate access to internal portions of the hopper for cleaning.

Abstract: A pump assembly has a hopper adapted to hold a wet concrete mass and having a front wall formed with a front port centered on a front axis perpendicular to the front wall at the front port and a rear wall formed with two rear ports centered on respective rear axes perpendicular to the rear wall at the rear ports and generally parallel to the front axis. Respective piston pumps secured to the rear wall outside the hopper over the rear ports are operable to draw portions of the mass out of the hopper and expel them back into the hopper through the respective rear ports. An outlet conduit is connected to the front wall outside the hopper over the front port and a distributor pipe in the hopper has a front end fitted and aligned with the front port and a rear end engageable over and alignable with either of the rear ports. A buttress formation fixed on front end of the distributor pipe defines outside the hopper a buttress plane parallel to the front and rear planes.

Abstract: The valve has a shutter mechanism which is movable within a housing and is provided at one end with at least one inlet which is movable across one or more housing openings and at the opposite end with an outlet surrounded by a sealed contact joint which is movable across a delivery pipe opening in the housing. This sealed contact joint surrounds the delivery pipe opening in the housing and contacts either the inside wall of the housing or a face plate arranged on the inside wall of the housing in all intermediate and final positions of the shutter mechanism. With the aim of reducing wear and producing a permanent seal, the sealed contact joint is in the form of a compressible sealing ring with a slotted or kidney-shaped cross-section which serves to wipe the flat and smooth face plate or inside wall of the housing.

Abstract: A fluid passage change over valve unit for use in concrete pumps wherein a passage change over valve member located within a hopper is connected at its outlet port to a delivery line for pivoting about the latter so that an inlet port thereof is swung to alternately communicate with a pair of piston pumps having pump openings into the hopper. The valve unit is provided with a pair of guide members disposed along both sides of the valve member. One end of each guide member opens upwards and the other end is disposed to come into alignment with the opening of corresponding one of the piston pumps for guiding a fluid concrete within the hopper to the one pump when the valve member communicates with the other pump.

Abstract: A pump assembly for concrete comprises a hopper adapted to hold the mass and having a front wall formed with a front port centered on a front axis perpendicular to the front wall at the front port and a rear wall formed with two rear ports centered on respective rear axes perpendicular to the rear wall at the rear ports and generally parallel to the front axis. Respective piston pumps secured to the rear wall outside the hopper over the rear ports can draw portions of the mass out of the hopper and expel the drawn-out portions back into the hopper through the respective rear ports. An outlet conduit is connected to the front wall outside the hopper over the front port. A generally curved or nonstraight distributor pipe in the hopper has a front end engaged over and aligned with the front port, a rear end engageable over and alignable with either of the rear ports, and a generally arcuate centerline crossing the front axis at the front port and extending parallel to the rear axes at the rear wall.

Abstract: A viscous material pump, in particular for the conveyance of concrete through a housing (3) of a switch tube (2) has a swivel body (26) fastened on an axially supported pivot shaft (44). The swivel body alternately connects a discharge opening (25) mounted in a housing wall with two inlet openings (6, 7) arranged in another housing wall. The centers of the inlet and outlet openings, respectively, are arranged in radial displacement from the shaft axis (35). The displacement of the inlet openings (6, 7) and the discharge opening (25) from the shaft axis (35) differs and is so selected that the displacement (R.sub.1) of the inlet openings (6, 7) is larger than the displacement (R.sub.2) of the discharge opening (25).

Abstract: A valve structure for a viscous material pump having a material reservoir, a pair of alternately operable material conveying cylinders, discharge conduit means, and a valve control means coupled to the valve structure and to the material conveying cylinders. The valve structure has a pair of movable swivel pipes extending between the conveying cylinders and the discharge conduit means. Each of the swivel pipes has an opening movable over one of the conveying cylinders to receive the contents discharged therefrom and a plate movable over said one conveying cylinder to block same.

Abstract: The valve has a shutter mechanism which is movable within a housing and is provided at one end with at least one inlet which is movable across one or more housing openings and at the opposite end with an outlet surrounded by a sealed contact joint which is movable across a delivery pipe opening in the housing. This sealed contact joint surrounds the delivery pipe opening in the housing and contacts either the inside wall of the housing or a face plate arranged on the inside wall of the housing in all intermediate and final positions of the shutter mechanism. With the aim of reducing wear and producing a permanent seal, the sealed contact joint is in the form of a compressible sealing ring with a slotted or kidney-shaped cross-section which serves to wipe the flat and smooth face plate or inside wall of the housing.