VALVE FOR THICK MATTER AND METHOD FOR ACTUATING A VALVE FOR THICK MATTER

Abstract

A valve for thick matter and method for actuating a valve for thick matter, wherein, in a first switching operation, a valve element is switched between a first switching state (A) and a second switching state (B) by a first volume of hydraulic fluid being supplied to a control cylinder, and, in a second switching operation, the valve element is switched between the second switching state (B) and a third switching state (C) by a second volume of hydraulic fluid being supplied to a control cylinder. The first and second volumes of hydraulic fluid are supplied to the control cylinder by displacement of a metering piston of a metering cylinder from a first end position to a second end position.

Claims

1. A method for actuating a thick matter valve, in which with a first switching operation a valve member (26) is switched between a first switching state (A) and a second switching state (B) by a first volume of hydraulic fluid being supplied to a control cylinder (28, 29), and in which the valve member with a second switching operation is switched between the second switching state (B) and a third switching state (C) by a second volume of hydraulic fluid being supplied to a control cylinder (28, 29), wherein the first volume of hydraulic fluid is supplied to the control cylinder (28, 29) by a metering piston of a metering cylinder (33, 34, 35) being displaced from a first end position into a second end position and wherein the second volume of hydraulic fluid is supplied to the control cylinder (28, 29) by a metering piston of a metering cylinder (33, 34, 35) being displaced from a first end position into a second end position.

2. The method of claim 1, wherein the first switching operation is driven with a first metering cylinder (33) and the second switching operation is driven with a second metering cylinder (34).

3. The method of claim 1, wherein the valve member (26) is switched with a third switching operation between the third switching state (C) and a fourth switching state (D), wherein the volume of hydraulic fluid for the third switching operation corresponds to the sum of the volumes of the first switching operation and the second switching operation.

4. The method of claim 1, wherein a metering cylinder (36, 44) is used in order to drive a first switching operation and a second switching operation.

5. The method of claim 4, wherein the metering cylinder (36, 44) has a plurality of metering pistons (37, 38).

6. The method of claim 5, wherein, for a first switching operation, the volume of hydraulic fluid conveyed with the first metering piston (37) is supplied to the control cylinder (28, 29) and, for a second switching operation, the volume of hydraulic fluid conveyed with the second metering piston (38) is supplied to the control cylinder (28, 29).

7. The method of claim 6, wherein, for a third switching operation, the sum of the volume of hydraulic fluid conveyed with the first metering piston (37) and with the second metering piston (38) is supplied to the control cylinder (28, 29).

8. The method of claim 1, wherein the valve member (26) is activated with a pivot movement and in that the pivot angle for a switching operation is between 10? and 30?.

9. The method of claim 1, wherein, for a switching operation, a torque which is greater than 1 kNm, preferably greater than 5 kNm, more preferably greater than 10 kNm is applied.

10. The method of claim 1, wherein the switching time is shorter than 1 second, preferably shorter than 0.5 seconds, more preferably shorter than 0.3 seconds.

11. A thick matter valve having a valve member (26) which can be switched between a first switching state (A), a second switching state (B) and a third switching state (C), said thick matter valve comprising a control cylinder (28, 29) for actuating the valve member (26) and one or more metering cylinders (33, 34, 35, 36, 44) which have a first end position and a second end position of a metering piston, wherein, to switch the valve member between the first switching state (A) and the second switching state (B), a first volume of hydraulic fluid is supplied to the control cylinder by a metering piston being displaced between a first end position and a second end position, and wherein, to switch the valve member between the second switching state (B) and the third switching state (C), a second volume of hydraulic fluid is supplied to the control cylinder (28, 29) by a metering piston being displaced between a first end position and a second end position.

12. A thick matter pump comprising a first conveying cylinder (22), a second conveying cylinder (23) and a thick matter valve (25) of claim 11, wherein a first inlet opening (30) of the thick matter valve (25) is connected to the first conveying cylinder (22) and a second inlet opening (31) of the thick matter valve (25) is connected to the second conveying cylinder (23).

13. A method for actuating a thick matter valve, said thick matter valve having a valve member connected to a control cylinder responsive to a first volume of hydraulic fluid to move the valve member from a first switching state (A) to a second switching state (B) in a first switching operation and the control cylinder is responsive to a second volume of hydraulic fluid to move the valve member from the second switching state (B) to a third switching state (C) in a second switching operation, said method comprising: supplying the first volume of hydraulic fluid to the control cylinder by displacing a metering piston of a metering cylinder from a first end position to a second end position; and supplying the second volume of hydraulic fluid to the control cylinder, wherein supplying the second volume of hydraulic fluid comprises: displacing the metering piston of the metering cylinder from the first end position to the second end position; or displacing the metering piston of the metering cylinder from the second end position to the first end position; or displacing a second metering piston of the metering cylinder from a first end position to a second end position; or displacing a metering piston of a second metering cylinder from a first end position to a second end position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The invention is described below by way of example with reference to the appended drawings and advantageous exemplary embodiments. In the drawings:

[0031] FIG. 1: shows a vehicle which is provided with a thick matter pump according to the invention;

[0032] FIG. 2: shows a schematic illustration of a thick matter pump according to the invention;

[0033] FIG. 3: shows a functional drawing of a working cycle of a thick matter pump according to the invention;

[0034] FIG. 4: shows a schematic illustration of the control of a thick matter valve according to the invention;

[0035] FIG. 5: shows the view from FIG. 4 in an alternative exemplary embodiment of the invention;

[0036] FIGS. 6, 7: show exemplary embodiments of metering cylinders for a thick matter valve according to the invention;

[0037] FIGS. 8, 9: show schematic illustration of pipe switches according to the invention.

DETAILED DESCRIPTION

[0038] A truck 14 which is shown in FIG. 1 is provided with a concrete pump 5 which conveys liquid concrete from a prefilling container 16 through a conveying line 17. The concrete pump is a thick matter pump 15 in the context of the invention. The conveying line 17 extends along a mast arm 18 which is rotatably supported on a slewing ring 19. The mast arm 18 comprises three mast arm segments 20, 21, 22 which are connected to each other in an articulated manner. By the mast arm segments 20, 21, 22 being pivoted relative to each other via the joints, the mast arm 18 can be displaced between a folded-in state and a folded-out state. The conveying line 17 extends over the distal end of the third mast arm segment 22 so that in the folded-out state of the mast arm 18 the liquid concrete can be discharged in a region remote from the concrete pump 15.

[0039] The concrete pump 15 comprises according to FIG. 2 a first conveying cylinder 22 and a second conveying cylinder 23 which in alternating operation draw liquid concrete from the prefilling container 16 and convey it in the direction of a through-opening 24. With a thick matter valve 25 which is arranged between the conveying cylinders 22, 23 and the through-opening 24, the flow of the liquid concrete between the conveying cylinders 22, 23 and the through-opening 24 is controlled. The thick matter valve comprises a valve member 26 which, with respect to a pivot axis 32 is pivotably supported and which can be switched by means of an actuation lever 27 between different switching states. The thick matter valve 25 comprises a first control cylinder 27 and a second control cylinder 28 which act in a hydraulically driven manner on the actuation lever 27.

[0040] The thick matter valve 25 has according to FIG. 3 a plurality of switching states which during a working cycle of the concrete pump 15 follow each other as follows. In a switching state A, the control cylinder 28 is completely extended and the actuation lever 27 has been moved in a counter-clockwise direction into the outermost position thereof. The valve member 26 opens a first through-opening 20 which is connected to the inner space of the first conveying cylinder 22. The first conveying cylinder 22 conveys in this phase of the working cycle liquid concrete with a forward movement through the first through-opening 30 and the inner space of the valve member 26 to the through-opening 24. The second through-opening 31 is released in the switching state A so that the second conveying cylinder 23 can draw liquid concrete from the prefilling container 16 with a backward movement.

[0041] Starting from the switching state A, the thick material valve is switched into the switching state B by the second control cylinder 29 being extended slightly. The actuation lever 27 is pivoted in a clockwise direction into a position which is located between the outer position from switching state A and a central position of the actuation lever 27. The first through-opening 30 remains open so that the first conveying cylinder 22 can continue to convey liquid concrete through the valve member 26. The second through-opening 31 is closed, the second conveying cylinder 23 compresses the liquid concrete in the second conveying cylinder 23 with a forward movement.

[0042] Starting from a switching state B, switching is carried out to a switching state C by the second control cylinder 29 being extended further so that the actuation lever 27 is arranged in a central position. The valve member 26 opens the first through-opening 30 and the second through-opening 31 so that both conveying cylinders 22, 23 can convey liquid concrete through the valve member 26 in a parallel manner.

[0043] Starting from the switching state C, switching is carried out to a switching state D by the second control cylinder 29 being extended completely, so that the actuation lever 27 is moved into the outermost position thereof when viewed in the clockwise direction. The valve member 26 opens the second through-opening 31 so that the second conveying cylinder 23 can convey liquid concrete through the valve member 26. The first through-opening 30 is released so that the first conveying cylinder 22 can draw liquid concrete from the prefilling container 16 with a backward movement.

[0044] Starting from the switching state D, the thick matter valve is switched into the switching state E by the first control cylinder 28 being extended slightly. The actuation lever 27 is pivoted in a counter-clockwise direction into a position which is located between the outer position from the switching state D and a central position of the actuation lever 27. The second through-opening 31 remains open so that the second conveying cylinder 23 can continue to convey liquid concrete through the valve member 26. The first through-opening 30 is closed, the second conveying cylinder 23 compresses the liquid concrete in the first conveying cylinder 22 with a forward movement.

[0045] Starting from the switching state E, the thick matter valve is switched into the switching state F by the first control cylinder 28 being extended further so that the actuation lever 27 is arranged in a central position. The valve member 26 opens the first through-opening 30 and the second through-opening 31 so that both conveying cylinders 22, 23 can convey liquid concrete through the valve member 26 in a parallel manner.

[0046] Starting from the switching state F, switching is carried out to the switching state A by the first control cylinder 28 being extended completely. A new working cycle of the concrete pump 15 consequently begins.

[0047] Between the switching states A and F there is a pivot angle of approximately 80?. The switching operations between the switching states A, B, C and between the switching states D, E, F extend in each case over a pivot angle of approximately 20?. The torque which has to be applied for the switching operations is approximately 30 kNm. A switching time of approximately 0.3 seconds is provided for a switching operation. The dwell time in a switching state prior to the next witching operation is shorter than 1 second.

[0048] The control of the control cylinders 28, 29 is carried out according to FIG. 4 via a plurality of metering cylinders 33, 34, 35 which are each configured to supply to the control cylinders 28, 29 a defined quantity of hydraulic fluid. For the transition from the switching state A to the switching state B, the first metering cylinder 33 is displaced from a first end position into a second end position, whereby a volume of 440 ml of hydraulic fluid is supplied to the second control cylinder 29. For the transition from the switching state B to the switching state C, the second metering cylinder 34 is actuated, whereby a volume of 530 ml of hydraulic fluid is supplied to the second control cylinder 29. For the transition from the switching state C to the switching state D, the third metering cylinder 35 is actuated, whereby a volume of 970 ml of hydraulic fluid is supplied to the second metering cylinder 29. Accordingly, the transition between the switching states D, E, F is carried out in the opposing rotation direction by the metering cylinders 33, 34, 35 being activated in the opposing direction.

[0049] In each of the switching operations, precisely one of the metering cylinders 33, 34, 35 is moved from a first end position into a second end position. This requires in each case the actuation of only a single actuation member of the metering cylinder 33, 34, 35 by means of which the movement of the respective metering piston is initiated, the movement of the metering piston terminates automatically when the second end position is reached without another actuation member having to be actuated and without another control or regulation operation being carried out.

[0050] In the alternative exemplary embodiment according to FIG. 5, the control of the control cylinders 28, 29 is carried out with only two metering cylinders 34, 35. For the transition from the switching state A to the switching state B, the first metering cylinder 33 is again activated, for the transition from the switching state B to the switching state C the second metering cylinder 34 is activated. The transition from the switching state C to the switching state D is carried out by both the first metering cylinder 34 and the second metering cylinder 35 being activated. The sum of the volume of the two metering cylinders 34, 35 corresponds to the larger pivot angle which the valve member 26 travels between the switching state C and the switching state D. The switching in the opposite direction is carried out for the transition from the switching state D to E in turn with the first metering cylinder 34, for the transition from the switching state E to the switching state F with the second metering cylinder 35 and from the switching state F to the switching state A with the two metering cylinders 34, 35 together.

[0051] The metering cylinders 33, 34, 35 may be components which are separate from each other, with mutually separate cylinders and pistons which are arranged therein. A configuration in the form of a hydraulic block is also possible, wherein a plurality of cylinders are formed in the hydraulic block.

[0052] Alternatively, the invention may also be implemented by a single metering cylinder being provided with a plurality of metering chambers. In FIG. 6, a metering cylinder 36 in the form of a differential cylinder is shown. Two pistons 37, 38 which are connected to each other by means of a piston rod 39 are arranged in the metering cylinder 36. Between the first position 37 and an opposing front wall 40, a first metering chamber 41 is enclosed. Between the second piston 38 and a central wall 42, a second metering chamber 43 is enclosed. When the piston is moved out of the right end position shown in FIG. 6 into the left end position, the hydraulic fluid is displaced from both metering chambers 41, 43, wherein the volume in the second metering chamber 43 is smaller than the volume of the first metering chamber 41 as a result of the piston rod 39 which is arranged in the metering chamber 43. When the piston is moved in the opposite direction, the reverse is true. By the control cylinders 28, 29 being connected in an appropriate manner to the first metering chamber 41, to the second metering chamber 43 or to both metering chambers 41, 43 at the same time, all the switching operations shown in FIGS. 4 and 5 can be controlled.

[0053] Another exemplary embodiment of a metering cylinder 44 which is suitable for the invention is shown in FIG. 7. The metering cylinder 44 has three pistons 45, 46, 47 of which the central piston 45 has a larger diameter and of which the two outer pistons 46, 47 have a smaller diameter. The three pistons 45, 46, 47 are connected to each other by means of a piston rod 48. In the right end position, the piston 47 abuts the right front wall 49. In the left end position, the piston 46 abuts the left front wall 50. When the pistons 45, 46, 47 are moved from the right end position into the left end position, a first volume of hydraulic fluid is displaced from the outer piston 46 and a second volume of hydraulic fluid is displaced from the central piston 45. This applies accordingly with the reverse movement direction of the pistons 45, 46, 47. By either the volume which is displaced by the outer piston 46, 47 or the volume which is displaced by the central piston 45 or a sum of both volumes being supplied to the control cylinders 28, 29, all the switching operations of the thick matter valve 25 as shown in FIGS. 4 and 5 can be controlled.

[0054] According to FIG. 8, the thick matter valve according to the invention can also be used in the form of a pipe switch 51 which is not a component of a concrete pump. The pipe switch 51 has two inlet openings 52, 53 and a through-opening 54. There is connected in each case to the inlet openings 52, 53 a pipeline (not shown) through which a liquid concrete is conveyed to the pipe switch 51. By switching the thick matter valve, either the liquid concrete coming from the first inlet opening 52 or the liquid concrete coming from the second inlet opening 53 or the liquid concrete coming from the two inlet openings 52, 53 can be directed to the through-opening 54. It is also possible for the thick matter valve according to the invention to be used in a pipe switch 55 which is shown in FIG. 9 and which has an inlet opening 56 and two through-openings 57, 58.