Thick Stock Valve

Abstract

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

Claims

1. A thick stock valve with a first through opening (27), a second through opening (28) and a valve member (32) associated with both through openings (27, 28), wherein the valve member (32) is mounted to pivot with respect to a pivot axis (36), the valve member (32) has a sealing face (38) that is curved concentrically with the pivot axis (36), the valve member (32) in a first state (30) opens the first through opening (27) and closes the second through opening (28), the valve member (32) in a second state (29) opens the second through opening (28) and closes the first through opening (27), and the valve member (32) comprises a sealing part (35) and a pivot part (34), the pivot part (34) mounted to rotate in the pivot axis (36) and the sealing part (35) is connected to the pivot part (34) via a connection structure (37).

2. The thick stock valve of claim 1, comprising a housing (46) defining an inner space and the valve member (32) is arranged in said inner space.

3. The thick stock valve of claim 1, wherein an intermediate face of said housing (46) is arranged between the first through opening (27) and the second through opening (28), said intermediate face having a curvature which is concentric with the pivot axis (36).

4. The thick stock valve of claim 1, wherein in a third switching state the valve member (32) is situated between the first through opening (27) and the second through opening (28).

5. The thick stock valve of claim 1, wherein the connection structure (37) is rigid to torques acting relative to the pivot axis (36).

6. The thick stock valve of claim 1, wherein the connection structure (37) allows a movement of the sealing part (35) relative to the pivot part (34) in a radial direction.

7. The thick stock valve of claim 1, wherein the connection structure comprises an elastic element (37) situated between the sealing part (35) and the pivot part (34).

8. The valve of claim 1, wherein an elastic element is situated between a shaft (33) of the valve member (32) and a housing (46) of the valve.

9. The thick stock valve of claim 1, wherein the valve member (32) comprises two stub shafts (33) mounted in the pivot axis (36) and in that the stub shafts (33) enclose a free space between them.

10. The thick stock valve of claim 1, wherein the valve member (32) comprises one leg (51, 52, 53) which extends between the pivot axis (36) and the sealing face (38), and in that the leg (51, 52, 53) is spaced apart from an end face of a housing (46) of the thick stock valve (26).

11. The thick stock valve of claim 1, wherein the valve member (32) has a scraper (55), which is moved along an end face of the housing (46) of the thick stock valve (26) during a switching process of the valve member (32).

12. The thick stock valve of claim 1, wherein the valve member (32) comprises an outer face (43, 44 47, 49) by which a pressure difference present across the valve member (32) is transformed into a force acting in a radial direction.

13. A thick stock pump having a thick stock valve of claim 1, wherein the thick stock pump is designed such that the material placed in motion by a conveying member of the pump enters through the first and/or second inlet opening (27, 28) into the inner space of the thick stock valve.

14. The thick stock pump of claim 13, wherein the thick stock pump is designed to pivot said valve member (32) between said first and second states when no pressure difference is present across the valve member (32).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The invention will now be described below as an example with reference to the accompanying drawings by means of advantageous embodiments. There are shown:

[0047] FIG. 1: a vehicle with a thick stock pump, equipped with a thick stock valve according to the invention;

[0048] FIG. 2: a block diagram of a thick stock pump equipped with a thick stock valve according to the invention (in hydraulic notation);

[0049] FIG. 3: a perspective representation of a thick stock pump with a thick stock valve according to the invention;

[0050] FIG. 4: a sectional representation of the pump of FIG. 3;

[0051] FIGS. 5 to 8: schematic representations of different states of the thick stock pump of FIG. 3;

[0052] FIG. 9: a schematic representation of a valve member according to the invention;

[0053] FIG. 10: a representation of the pressures acting on the sealing part of the valve member;

[0054] FIG. 11: a valve member of a thick stock valve according to the invention in partly sectional representation;

[0055] FIGS. 12 & 13: valve members in alternative embodiments of the invention; and

[0056] FIG. 14: a sectional representation of the embodiment of FIG. 13.

DETAILED DESCRIPTION

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] The operating sequence of the pump will now be explained below with the aid of the schematic representations of FIGS. 5 to 8.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.