Thick Stock Valve

BACKGROUND

The invention relates to a thick stock valve with a first through opening, a second through opening and with a valve member which interacts with both through openings.

Such valves are used in the conveying of thick stock, such as fresh concrete or mortar. There is in this case a first conveying state in which the thick stock passes through the first through opening, and a second conveying state in which the thick stock passes through the second through opening. The thick stock valve serves for releasing that through opening for the thick stock which is suitable for the particular conveying state.

Thick stock valves in which a valve member is associated with two through openings are known, cf. DE 10 2013 215 990 A1, U.S. Pat. No. 8,827,657, DE 195 03 986 A1, DE 10 2005 008 938 A1. The valve member has the form of an S-shaped pipe segment, whose one end can be coupled optionally to the first through opening or the second through opening. This is mechanically complicated.

SUMMARY OF THE INVENTION

The problem which the invention proposes to solve is to propose a thick stock valve having a more simple construction. Starting from the mentioned prior art, the problem is solved with the features of claim 1. Advantageous embodiments are indicated in the dependent claims.

In the thick stock valve according to the invention, the valve member associated with both through openings is mounted so as to be able to pivot with respect to a pivot axis and has a sealing face that is curved concentrically with the pivot axis. The valve member in a first state releases the first through opening and closes the second through opening. The valve member in a second state releases the second through opening and closes the first through opening. In one variant of the invention, the valve member comprises a sealing part and a pivot part. The pivot part is mounted so as to be able to rotate in the pivot axis. The sealing part is connected to the pivot part via a connection structure.

Thanks to the design according to the invention, there is a simple spatial correlation between the through openings and the pivot axis of the valve member, making possible a simple design configuration of the thick stock valve. If the sealing part is connected to the pivot part via a connection structure, a reliable sealing effect can be accomplished between the sealing part and the through openings.

Thick stock is a collective term for hard to convey media. Thick stock can be, for example, a substance with coarse-grained components, a substance with aggressive components, or the like. The thick stock may also be a bulk material. In one embodiment, the thick stock is fresh concrete. Fresh concrete contains grains up to a size of more than 30 mm, binds and forms deposits in blind spaces and for these reasons is difficult to convey.

The valve member may be arranged in an inner space of the thick stock valve. The thick stock valve according to the invention may be configured such that the thick stock enters through the through openings into the inner space of the thick stock valve. The thick stock valve may additionally have an exit opening through which the entered thick stock once again leaves the valve. A pipe may be connected to the exit opening, through which pipe the further transport of the thick stock occurs. The path between the through openings and the exit opening may be set up such that it does not extend through the valve member.

The first and the second through opening may each have a sealing face, designed to interact with the sealing face of the valve member. The sealing face can be, for example, an inner surface of a housing of the thick stock valve, extending around the through opening with a round shape. The sealing faces of the through openings may have a curvature concentric with the pivot axis of the valve member. Thanks to the concentric curvature of the interacting sealing faces, the valve member can be rotated about the pivot axis corresponding to the axis of the curvature. In this way, it becomes possible for one of the openings to have a free flow through it, while on the other hand the sealing face of the valve member interacts in sealing manner with the sealing face of the other through opening. The term sealing is to be understood with regard to the area of application in which a hundred percent tightness is not demanded.

In one embodiment, the concentric curvature corresponds to a segment of a cylinder envelope, where the cylinder axis is equal to the pivot axis. In this embodiment, the radial spacing between the sealing face of the valve member and the pivot axis is constant over the length of the pivot axis. Embodiments are also included in which the radial spacing varies along the pivot axis. In each case, the curvature may correspond to a circle segment in the circumferential direction.

An intermediate face may be arranged between the first through opening and the second through opening, said intermediate face likewise having a curvature which is concentric with the pivot axis. In this way, it is possible to create a continuous contour concentric with the pivot axis, said contour extending from the first through opening to the second through opening by way of the intermediate face.

Besides the mentioned switching states in which the valve member closes the first or the second through opening, the thick stock valve may have a third switching state (intermediate state), in which both the first through opening and the second through opening are released. In the intermediate state, the valve member may be situated between the first through opening and the second through opening. The spacing between the two through openings may be so large that both of the through openings are entirely released. This has the benefit that the edges of the sealing face are not exposed to the material flow extending through the openings. It is also possible for one or both of the through openings to still be partly covered by the valve member.

The valve member may comprise a sealing part and a pivot part, wherein the pivot part is mounted so as to be able to rotate in the pivot axis. A motorized drive may engage with the pivot part in order to bring about the switching processes between the different states of the thick stock valve.

The valve member may comprise a connection structure, which produces a connection between the sealing part and the pivot part. The connection structure may be designed so that it is rigid to torques acting relative to the pivot axis. Rigid in this sense means that, upon a turning of the pivot part relative to the pivot axis, the sealing part also executes the corresponding pivot movement.

In regard to the radial direction, the connection structure may allow a movement of the sealing part relative to the pivot part. By such a relative movement, the radial spacing between the sealing face and the pivot axis may be adapted such that the desired sealing effect is produced between the valve member and the through opening.

The connection structure may comprise an elastic element situated between the sealing part and the pivot part. In the starting state of the thick stock valve, the elastic element may be compressed. If wear occurs between the sealing faces during the operation, the elastic element is then be stretched out. Thus, the wear is automatically compensated for.

In addition to or alternatively to this, the valve member according to the invention may comprise a drive in order to move the sealing part in the radial direction relative to the pivot part. The drive may be utilized to adapt the position of the sealing part to the pivot part during operation. It is also possible to utilize the drive to adjust the spring tension of the elastic element. For example, the drive may be a hydraulic drive or a mechanical drive.

In one variant, the valve member comprises a rigid connection between the sealing face and the pivotably mounted shaft or the pivotably mounted stub shafts. A radial mobility of the sealing face relative to the valve housing may result therefrom when the shaft or the stub shafts are mounted elastically with respect to the valve housing. For example, one or more elastic elements may be provided, extending around the shaft or the stub shafts. This embodiment has the advantage that the elastic elements are not affected by the flow of thick stock.

The valve member may be arranged in a housing of the thick stock valve according to the invention. The valve member may be arranged next to an end wall of the housing, the end axle being oriented at right angles to the pivot axis. The pivot movement of the valve member then runs parallel to the end wall. The valve member may be spaced away from the end wall so that even the coarse-grained components of the thick stock have room between the valve member and the end wall. This facilitates the actuating of the valve member.

In one alternative embodiment, the spacing between the valve member and the end wall is smaller than the coarse-grained components of the thick stock. The valve member may comprise a scraper, which pushes the thick stock to the side along the end wall when the valve member is actuated, so that no grains can become clamped between the valve member and the end wall. The scraper may rest against the end wall or have a slight spacing from the end wall.

The housing may have a second end wall, so that the valve member is situated between the first and the second end wall. The interaction between the valve member and the second end wall can be organized accordingly.

A shaft of the valve member can be mounted in the housing of the thick stock valve. Two bearings can be arranged here such that they enclose the valve member between them. A shaft can extend between the bearings, being a component of the pivot part of the valve member.

The thick stock valve according to the invention may be designed such that a straight connection section between an entry opening and the exit opening of the thick stock valve intersects the pivot axis. If a shaft of the valve member extends continuously along the pivot axis, the material flow must then be carried past the shaft along a curved trajectory.

In order to keep the flow resistance low, the valve member may comprise a guide surface by which the material flow is conducted past the shaft. The guide surface may be adjacent to the sealing face (in terms of the direction of movement of the valve member) and define a substantially straight path past the valve member and the pivot axis. The guide surface may be a flat guide surface, in particular one which can be oriented parallel to the pivot axis. At its end adjacent to the exit opening, the guide surface may be provided with a recess, in order to facilitate the passage of the material flow into the exit opening. The valve member may comprise two such guide surfaces, the sealing face being enclosed between the guide surfaces. Depending on the switching state of the valve, the material flow can be guided either along one and/or the other guide surface.

Such a guide surface may be especially advantageous when the valve member is designed such that the pivot axis is enclosed in the body of the valve member. The elastic element of the valve member may extend around the shaft of the valve member or be arranged between the pivot axis and the sealing face.

In order to keep the flow resistance low, the shaft may comprise two stub shafts, which are led in bearings of the valve housing. The connection between the two stub shafts may be produced by a connection structure, whose spacing from the sealing face is less than the spacing between the pivot axis and the sealing face. Since the connection structure does not extend along the pivot axis, but instead is situated closer to the sealing face, a clear space remains which is available to the material flow on its path toward the exit opening. In particular, the connection structure may be configured such that a straight line extending from the midpoint of the through opening not closed to the midpoint of the outlet opening does not intersect the valve member.

For the connection between the shaft and the sealing part, the connection structure may have a leg extending up to the sealing part. In particular, the leg may be oriented in the radial direction. In regard to the sealing part, the leg may be situated centrally. If the leg has a spacing from the end walls of the valve housing, the thick stock can flow properly around it.

It is also possible for the connection structure to have two legs extending in the direction of the sealing part. The legs may be parallel to each other and oriented in the radial direction. The legs may be arranged so that a region arranged between the pivot axis and the center of the sealing part is kept clear, so that the thick stock can flow through it. In regard to the spacing between the pivot axis and the sealing face of the valve member, the region kept clear may extend across at least 10%, preferably at least 30%, further preferably at least 50%.

The two legs may have a spacing from the end walls of the housing. Alternatively, the legs may be configured as scrapers, so that the thick stock is pushed aside along the end face when the valve member is actuated.

If the thick stock valve according to the invention is used such that the material flow enters through one of the through openings into the inner space of the valve, extends past the valve member and exits the valve once more through an exit opening (pumping mode), there is generally a pressure difference present between the inner space of the thick stock valve and an outer space adjoining the through opening closed by the valve member. The thick stock valve may be designed such that the pressure difference exerts a force on the valve member, which strengthens the sealing effect.

If the pressure in the inner space is higher than that in the outer space, the valve member may then be pressed in the radial direction against the sealing face of the through opening. The directional term radial pertains to the pivot axis of the valve member. For this purpose, the valve member may have an outer face by which pressure present in the inner space is transformed into a force acting in the radial direction. Outer face denotes an area of the valve member in contact with the thick stock in the inner space of the thick stock valve.

In particular, the valve member may have an outer face, situated opposite the sealing face. The outer face may be oriented such that it intersects the radial direction perpendicularly. A pressure acting on the outer face is then oriented such that it directly strengthens the sealing effect.

It is also possible for the valve member to have an outer face inclined with respect to the radial direction, so that only a portion of the pressure force acts in the direction of the sealing face.

The valve member may also have two oppositely oriented inclined outer faces. Opposite means that the outer faces are oriented such that the components of the pressure force acting in the radial direction add up.

If the thick stock valve according to the invention is used such that the material flow moves in the reversed direction (suction mode), the pressure difference generally cannot then be used to intensify the sealing effect of the valve member. The sealing effect then results primarily from the force exerted from the pivot part on the sealing part. This force, as explained, may be produced either by an elastic biasing or by an active drive unit.

The invention moreover relates to a pump outfitted with such a thick stock valve. The thick stock valve may be arranged such that the material placed in motion by the conveying member of the pump during a pumping operation enters through the first and/or the second opening into the inner space of the thick stock valve.

The pump may comprise a first conveying cylinder and a second conveying cylinder. In each of the conveying cylinders there can be arranged a piston, which sucks in thick stock into the inner space of the conveying cylinder with a backward movement in the pumping operation and which delivers the thick stock in the direction of the through opening of the thick stock valve with a forward movement.

The conveying streams of the two conveying cylinders may be separated upstream from the thick stock valve and be combined into a common conveying stream with the thick stock valve. The conveying stream from the first conveying cylinder may enter through the first through opening of the thick stock valve into the inner space of the thick stock valve. The conveying stream from the second conveying cylinder may enter through the second through opening of the thick stock valve into the inner space of the thick stock valve.

The pistons may be actuated such that the backward movement occurs within a shorter interval of time than the forward movement. The beginning of the forward movement of the one piston may overlap with the end of the forward movement of the other piston. An interval of time then exists in which both pistons are conveying material in parallel in the direction of the thick stock valve.

The switching positions of the thick stock valve may be coordinated with the movement of the pistons in the conveying cylinders. If the piston of the first conveying cylinder is in the forward movement and the piston of the second conveying cylinder is in the backward movement, the thick stock valve can then be switched to the first state in which the first through opening is open and the second through opening is closed. If the piston of the second conveying cylinder is in the forward movement and the piston of the first conveying cylinder is in the backward movement, the thick stock valve can then be switched to the second state in which the second through opening is open and the first through opening is closed. In the intermediate phase, in which the pistons of both conveying cylinders are in the forward movement, the thick stock valve can be switched to a state in which none of the through openings are closed. Preferably, both of the through openings are open in this intermediate state of the thick stock valve.

If the piston of the first conveying cylinder is in the backward movement and the piston of the second conveying cylinder is in the forward movement, a pressure difference is then present across the first through opening of the thick stock valve. The pressure in the inner space of the thick stock valve corresponds substantially to the pressure exerted by the piston of the second conveying cylinder by its forward movement on the material. Upstream from the first through opening, the suction pressure of the first conveying cylinder is present, being much lower. This pressure difference, as described above, can be utilized to intensify the sealing effect between the valve member and the first through opening. Conversely, if the piston of the second conveying cylinder is in the backward movement and the piston of the first conveying cylinder is in the forward movement, the corresponding pressure difference is then present across the first opening of the thick stock valve.

A pressure difference which is present across the valve member is an impediment to a switching process of the thick stock valve. Therefore, the thick stock valve may be designed such that the switching process occurs when a pressure difference is present across the valve member that is reduced with respect to this pressure difference. For this, it is advantageous for the switching process to occur only if the backward movement of the piston whose through opening is closed by the valve member has been completed. It may be further advantageous for the switching process to occur only if the respective piston has begun its forward movement, so that a pressure has already been built up once more in front of the respective through opening.

The thick stock valve may be designed such that the switching process is finished before the backward movement of the other piston begins. In particular, the thick stock valve may be designed such that the switching process is finished before the forward movement of the other piston has ended. The switching process may be designed such that the valve member is moved from a first switching state, in which one of the through openings is closed and the other through opening is open, through an intermediate state in which none of the through openings is closed, to a second switching state in which the respective other through opening is closed or open. In particular, the pump may be designed such that the switching processes of the valve member are only undertaken if the pressure difference present across the valve member is small.

The preceding remarks pertain to the pumping mode of the pump. The pump may also be operated in the reverse direction in a suction mode. The suction mode may serve, for example, to clean the thick stock valve and an attached conveying line or to eliminate an obstruction in this area. The interplay of the conveying cylinders and the thick stock valve is then coordinated with each other in the reverse manner.

In the suction mode, a pressure difference present across the valve member generally has a tendency to decrease the sealing effect of the valve member. Therefore, the valve member should be designed such that even under such a negative pressure difference it has an adequate sealing effect, in that a force acting in the direction of the through opening is exerted on the sealing part via the pivot part.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described below as an example with reference to the accompanying drawings by means of advantageous embodiments. There are shown:

FIG. 1: a vehicle with a thick stock pump, equipped with a thick stock valve according to the invention;

FIG. 2: a block diagram of a thick stock pump equipped with a thick stock valve according to the invention (in hydraulic notation);

FIG. 3: a perspective representation of a thick stock pump with a thick stock valve according to the invention;

FIG. 4: a sectional representation of the pump of FIG. 3;

FIGS. 5 to 8: schematic representations of different states of the thick stock pump of FIG. 3;

FIG. 9: a schematic representation of a valve member according to the invention;

FIG. 10: a representation of the pressures acting on the sealing part of the valve member;

FIG. 11: a valve member of a thick stock valve according to the invention in partly sectional representation;

FIGS. 12 & 13: valve members in alternative embodiments of the invention; and

FIG. 14: a sectional representation of the embodiment of FIG. 13.

DETAILED DESCRIPTION

On the cargo surface of a truck 14 shown in FIG. 1 there is arranged a thick stock pump 15 in the form of a concrete pump. The thick stock pump 15 comprises a prefilling tank 16, into which the concrete is filled from a reservoir (not shown). The thick stock pump 15 sucks in the concrete from the prefilling tank and conveys the concrete through a connecting pipe 17, which extends along a distributing boom 18. The distributing boom 18 is mounted on a slew ring 19 and can be unfolded via several joints, so that the end of the pipe 17 can be placed into a position at a spacing from the truck 14. In this position, the concrete is brought out from the connecting pipe 17.

The thick stock pump according to FIG. 2 comprises a first conveying cylinder 21 and a second conveying cylinder 22. Each conveying cylinder 21, 22 comprises a piston, which sucks in concrete with a backward movement from the prefilling tank 16 and which conveys the concrete with a forward movement in the direction of an outlet 23 of the pump.

The first conveying cylinder 21 is associated with a first inlet valve 24. The inlet valve 24 is opened during the backward movement of the first conveying cylinder 21, so that the conveying cylinder 21 can suck in concrete from the prefilling tank 16. The inlet valve 24 is closed during the forward movement of the first conveying cylinder 21, so that the concrete can be conveyed in the direction of the pump outlet 23. The second conveying cylinder 22 is associated with a second inlet valve 25, whose switching processes are attuned accordingly to the backward and forward movements of the second conveying cylinder 22.

The pump comprises a thick stock valve 26, which forms a common outlet valve for the first conveying cylinder 21 and the second conveying cylinder 22. The thick stock valve 26 comprises a first through opening 27 for concrete delivered with the first conveying cylinder 21 and a second through opening 28 for concrete delivered with the second conveying cylinder 22. A valve member 32 of the thick stock valve in a first switching state 29 closes the first through opening 27 and leaves open the second through opening 28. In a second switching state 30, the thick stock valve 26 closes the second through opening 28 and leaves open the first through opening 27. In a third switching state 31 (intermediate state), both through openings 27, 28 are open.

The two conveying cylinders 21, 22 are driven such that the backward movement occurs within a shorter interval of time than the forward movement. The start of the forward movement of one conveying cylinder overlaps with the end of the forward movement of the other conveying cylinder. Thus, at every instant of time, concrete is being conveyed from at least one of the conveying cylinders 21, 22 in the direction of the thick stock valve 26.

The valve member 32 of the thick stock valve 26 is actively switched via a drive unit between the different switching states. If the first conveying cylinder 21 is in the forward movement and the second conveying cylinder 22 is in the backward movement, the thick stock valve 26 is then in the switching state 30 in which only the material flow coming from the first conveying cylinder 21 can pass through the thick stock valve 26. If the second conveying cylinder 22 is in the forward movement and the first conveying cylinder 21 is in the backward movement, the thick stock valve 26 is then in the switching state 29 in which only the material flow coming from the second conveying cylinder 22 can pass through the thick stock valve 26. In the overlapping phase in which both conveying cylinders 21, 22 are in the forward movement, the thick stock valve 26 is in the intermediate state 31, in which the material flows from both conveying cylinders 21, 22 can pass through the thick stock valve 26.

The two conveying cylinders 21, 22 have a basic speed for the forward movement. The basic speed of the forward movement is used while the respective other conveying cylinder 21, 22 is in the backward movement. The basic speed defines the material flow which is conveyed in this phase in the direction of the pump outlet 23. In the overlapping phase in which both conveying cylinders 21, 22 are in the forward movement, the speed is reduced as compared to the basic speed such that the speeds of the two forward movements add up to the basic speed. In this way, even during the overlapping phase, a constant material flow is maintained in the direction of the pump outlet 23.

FIG. 3 shows the thick stock pump according to the invention in a perspective representation. The inlet valve 25 is in the opened state, so that the corresponding entry opening 45 of the pump is clear and so that thick stock can be sucked in with the second conveying cylinder 22 from the prefilling tank 16 (FIG. 1). The first inlet valve 24 is in the closed state. When the piston of the first conveying cylinder 21 is in the forward movement, the material flow passes through the first through opening 27 of the thick stock valve 26 in the direction of the pump outlet 23, see FIG. 4.

The operating sequence of the pump will now be explained below with the aid of the schematic representations of FIGS. 5 to 8.

In FIG. 5A the valve member 32 of the thick stock valve 26 is switched so that it closes the through opening 27 of the first conveying cylinder 21 and so that said valve member leaves open the through opening 28 of the second conveying cylinder 22. The inlet valve 25 of the second conveying cylinder 22 is closed, see FIG. 5B. The second conveying cylinder 22 is in the forward movement and conveys concrete through the through opening 28 into the inner space of the thick stock valve 26 and to the pump outlet 23. Thanks to the pressure difference present across the valve member 32, the sealing effect between the valve member 32 and the through opening 27 is strengthened. The inlet valve 24 of the first conveying cylinder 21 is opened, so that the first conveying cylinder 21 can suck in concrete from the prefilling tank 16 with a backward movement through the inlet opening 44 of the pump.

The backward movement of the first conveying cylinder 21 ends sooner than the forward movement of the second conveying cylinder 22. FIG. 6 shows the state in which the forward movement of the first conveying cylinder 21 is starting and the forward movement of the second conveying cylinder 22 is just about to end. Both inlet valves 24, 25 are closed. The switchover of the thick stock valve 26 to the intermediate state 31 is starting, since the first conveying cylinder 21 has already built up pressure once more in front of the through opening 27, so that only a slight pressure difference is still present across the valve member 32. After the switchover, the thick stock valve 26 is in the intermediate state 31, in which the valve member 32 leaves open both the first through opening 27 and the second through opening 28. The speed of the forward movement is reduced for both conveying cylinders 21, 22, so that the conveying cylinders 21, 22 now together convey the amount of material that was previously conveyed by the second conveying cylinder 22 alone.

After the end of the forward movement of the second conveying cylinder 22, the inlet valve 25 is opened, see FIG. 7. In order to relieve the pressure, the second conveying cylinder 22 may already have performed a first backward movement prior to the opening of the inlet valve 25. When the inlet valve 25 is opened, the second conveying cylinder 22 sucks in concrete from the prefilling tank 16 with a backward movement through the inlet opening 45 of the pump. The first conveying cylinder 21 moves forward at its basic speed, so that the material flow to the pump outlet 23 is maintained unchanged.

In FIG. 8 once again the forward movement of the second conveying cylinder 22 begins, while the forward movement of the first conveying cylinder 21 ends. With the end of the forward movement of the first conveying cylinder 21, the cycle comes to an end and the pump again passes into the state of FIG. 5.

The valve member 32 of the thick stock valve 26 comprises per FIG. 9 a pivot part 34 and a sealing part 35. The pivot part 34 has two sections of a shaft 33, by which the pivot part is rotatably mounted with respect to a pivot axis 36. Between the shaft 33 and the sealing part 35 there is formed a connection structure 48, shown only schematically in FIG. 9. With the connection structure 48, the radial spacing between the sealing part 35 and the shaft 33 can be changed. On the other hand, the connection structure 48 is rigid to torques. Thus, if the shaft is turned about a particular angle, the sealing part 35 then executes a pivoting movement about the same angle.

The underside of the sealing part 35 forms a sealing face 38 in the form of a cylinder segment oriented concentrically to the pivot axis 36. The housing of the thick stock valve 26 has a matching mating surface, likewise in the form of a cylinder segment. The through openings 27, 28 of the thick stock valve 26 are formed in the mating surface. The sealing face 38 of the valve member 32 interacts with the mating surface of the valve housing and can seal off either the through opening 27 or the through opening 28, depending on the switching state.

FIG. 10 shows a state of the thick stock valve in which a higher pressure is present in the inner space of the thick stock valve than in front of the through opening 27 which is closed by the sealing part 35. The valve member 32 has an outer face 43 situated opposite the sealing face 38, against which the pressure of the material present in the thick stock valve 26 acts in the radial direction. The pressure difference with respect to the outer side helps strengthen the sealing effect between the valve member 32 and the valve housing. The valve member 32 moreover has two outer faces 47, 49 situated symmetrically to each other. A pressure of the material acting on the outer faces 47, 49 likewise has a component in the radial direction, so that the outer faces 47, 49 also help strengthen the sealing effect.

In the valve member 32 shown in FIG. 11, the pivot part 34 comprises a peg 50, which engages with a matching recess of the sealing part 35. With the peg 50, a sliding guide is formed, along which the sealing part 35 can move in the radial direction relative to the shaft 33. The sliding guide is rigid to forces in other directions.

Between the pivot part 34 and the sealing part 35 there is arranged a plate 37 of an elastic material. The plate 37 is part of the connection structure between the pivot part 34 and the sealing part 35. By pressure in the radial direction the plate 37 can be elastically compressed, so that the sealing part 35 moves closer to the pivot part 34 along the sliding guide.

The thick stock valve 26 according to the invention in the factory ready state is adapted such that the plate 37 is elastically compressed and consequently the sealing part 35 lies with an elastic pressure against the valve housing, which pressure is exerted by the plate 37 in the radial direction. If during the operation of the pump wear occurs for the valve member 32 or the valve housing, this can then be automatically compensated for by stretching of the elastic plate 37. In the suction mode, the plate 37 ensures that an adequate pressing force is applied between the sealing part 35 and the valve housing.

The valve member 32 shown in FIG. 11 is furthermore designed such that a free space is enclosed between two stub shafts 33, so that the material flow can move on the direct path from the through openings 27, 28 in the direction of the pump outlet 23. The pivot part 34 comprises two legs 51, 52, which extend in the radial direction and enclose the free space between them. In the radial direction, the free space extends across more than 50% of the spacing between the pivot axis 36 and the sealing face 38.

In the embodiment of FIG. 12, a free space is likewise enclosed between two stub shafts 33, in order to facilitate the movement of the conveying flow in the direction of the outlet opening. A central leg 53 extends in the radial direction and is connected at the center to the sealing part 35. Around the leg 53 there is enough room for the movement of the material flow. Moreover, the connection structure similar to FIG. 11 is configured with an elastic plate 37 and a sliding guide, not visible in FIG. 12.

FIG. 13 shows an alternative embodiment of a valve member 32 according to the invention. The sealing part 35 extends around the pivot part 34, so that a section of the pivot part 34 is received inside the sealing part. According to the sectional representation of FIG. 14, the pivot part 34 has a rectangular cross section inside the sealing part 35. The sealing part 35 has a slot matching the rectangular cross section, in which elastic elements 37 are arranged above and below the pivot part 34, so that the sealing part 35 can move in the radial direction relative to the pivot part 34, while a relative rotary movement between the sealing part 35 and the pivot part 34 is prevented. The pivot part 34 comprises a lever 39, with which a drive unit may engage in order to switch the valve member 32 between the different switching states.

The valve member 32 is dimensioned such that its two end faces pointing in the axial direction lie directly against the housing 46 of the thick stock valve 26. The end faces of the valve member are configured as scrapers 55. The scrapers 55 during a switching process of the valve member 32 push the thick stock to the side along the end face of the housing.

The side surfaces 57 of the valve member are configured as guide surfaces. Along the guide surfaces, the material flow is conveyed in the direction of the exit opening of the thick stock valve. At its top side the valve member 32 is provided with a recess 56, by which the movement of the material flow in the direction of the outlet opening is facilitated.

Thick Stock Valve

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CPC

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