THICK MATTER PUMP AND METHOD FOR CONVEYING THICK MATTER

Abstract

A thick matter pump with a conveying chamber which extends along a closed path from an inlet opening via an outlet opening back to the inlet opening, with the result that the conveying chamber forms a first connecting path and a second connecting path between the inlet opening and the outlet opening. A first piston performs a conveying movement along the first connecting path of the conveying chamber, with the result that, by way of the conveying movement, thick matter is conveyed out of the conveying chamber through the outlet opening, and thick matter is introduced through the inlet opening into the conveying chamber. A shut-off element is arranged in the conveying chamber, which shut-off element, in a first state, shuts off the second connecting path and, in a second state, opens the second connecting path in order to permit a movement of the first piston along the second connecting path. Moreover, the invention relates to a method for conveying thick matter.

Claims

1. A thick matter pump having a conveying chamber, which extends along a closed path from an inlet opening, via an outlet opening, back to the inlet opening, so that the conveying chamber forms a first connecting path and a second connecting path between the inlet opening and the outlet opening, having a first piston for performing a conveying movement along the first connecting path of the conveying chamber, so that with the conveying movement thick matter is conveyed from the conveying chamber through the outlet opening, and thick matter is introduced into the conveying chamber through the inlet opening, and having a shut-off element in the conveying chamber which shuts off the second connecting path in a first state, and opens up the second connecting path in a second state, in order to allow a movement of the first piston along the second connecting path, wherein a wall shell delimiting the conveying chamber is attached to the first piston, which wall shell extends over the entire length of the conveying chamber and is moved together with the first piston.

2. The thick matter pump of claim 1, wherein the wall shell has a greater extent in the circumferential direction than a connecting element which extends between a drive motor of the thick matter pump and the first piston.

3. The thick matter pump of claim 1, wherein the wall shell extends over a circumferential angle of at least 30°, preferably at least 60°, more preferably at least 90°.

4. The thick matter pump of claim 1, wherein the shut-off element is a shut-off valve which, in the first state, is arranged in the second connecting path and, in the second state, is spaced apart laterally from the second connecting path.

5. The thick matter pump of claim 1, wherein the shut-off element is a second piston which is likewise designed to perform a conveying movement along the first connecting path of the conveying chamber.

6. The thick matter pump of claim 5, wherein the second piston is at a standstill during the conveying movement of the first piston.

7. The thick matter pump of claim 5, wherein during the conveying movement of the first piston, the second piston is arranged in an intermediate position between the outlet opening and the inlet opening.

8. The thick matter pump of claim 5, wherein the conveying chamber comprises an inlet opening and two outlet openings and that three pistons are arranged in the conveying chamber.

9. The thick matter pump of claim 1, wherein a first wall shell of the first piston extends along a different circumferential portion of the conveying chamber to a second wall shell of the second piston.

10. The thick matter pump of claim 9, wherein the conveying chamber has a circumferential portion, which is kept free from the first wall shell and from the second wall shell and that the circumferential portion which is kept free is oriented to the inlet opening and the outlet opening.

11. The thick matter pump of claim 10, wherein the wall of the conveying chamber is formed in the circumferential portion that is kept free by a housing part of the thick matter pump.

12. The thick matter pump of claim 11, wherein the inlet opening and the outlet opening are arranged in the housing part.

13. The thick matter pump of claim 1, wherein a circumferential portion of the piston which travels over the inlet opening or the outlet opening is formed by an end piece made of hard metal.

14. The thick matter pump of claim 1, wherein an outlet of the thick matter pump is coupled with a supplementary conveying cylinder.

15. A method for conveying thick matter in which a first piston is moved in a conveying chamber, wherein the conveying chamber extends along a closed path from an inlet opening via an outlet opening back to the inlet opening, so that the conveying chamber forms a first connecting path and a second connecting path between the inlet opening and the outlet opening, wherein a wall shell which delimits the conveying chamber and extends over the entire length of the conveying chamber and which is moved together with the first piston is attached to said first piston, wherein in a first phase, the first piston is moved along the first connecting path from the inlet opening in the direction of the outlet opening, in order to convey thick matter through the outlet opening and to introduce thick matter through the inlet opening into the conveying chamber, while the second connecting path is shut off, and wherein in a second phase, the first piston is moved along the second connecting path.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The invention is described by way of example below with reference to the attached drawings with the help of advantageous embodiments. In the figures:

[0042] FIG. 1: shows a concrete pump vehicle having a thick matter pump according to the invention;

[0043] FIG. 2: shows a perspective representation of a thick matter pump according to the invention;

[0044] FIG. 3: shows the thick matter pump from FIG. 2 as a horizontal section;

[0045] FIG. 4: shows a schematic depiction of a thick matter pump according to the invention;

[0046] FIG. 5: shows different sectional views from FIG. 4;

[0047] FIG. 6, 7: show the view according to FIG. 5 in an alternative embodiment of the invention;

[0048] FIG. 8: shows a detail of the thick matter pump according to the invention as an enlarged depiction;

[0049] FIG. 9: shows a thick matter pump according to the invention as a vertical section;

[0050] FIG. 10-12: show schematic representations of various embodiments of thick matter pumps according to the invention;

[0051] FIG. 13: shows an operating sequence of the thick matter pump according to the invention;

[0052] FIG. 14-16: show alternative embodiments of thick matter pumps according to the invention.

DETAILED DESCRIPTION

[0053] A truck 14 shown in FIG. 1 is fitted with a concrete pump 15 which conveys liquid concrete from a pre-filling container 16 through a conveying line 17. The concrete pump is a thick matter pump 15 within the meaning of the invention. The conveying line 17 extends along a mast arm 18 which is rotatably mounted on a slewing ring 19. The mast arm 18 comprises three mast arm segments 20, 21, 22 which are connected to one another in an articulated manner. The mast arm 18 can switch between a folded-in state and a folded-out state, in that the mast arm segments 20, 21, 22 are pivoted relative to one another via the articulations. The conveying line 17 extends to beyond 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 delivered in a region remote from the concrete pump 15.

[0054] The thick matter pump 15 comprises a conveying chamber 23 which defines a circular path. An inlet opening 24 of the thick matter pump 15 is attached to the pre-filling container 16. An outlet opening 25 of the thick matter pump 15 is attached to the conveying line 17. A first piston 26 and a second piston 27 are arranged in the conveying chamber 23, each of which pistons fills the cross section of the conveying chamber 23. The pistons 26, 27 are attached to a central drive shaft 28, so that said pistons 26, 27 can be driven independently of one another. A rotation of the drive shaft 28 is transmitted via connecting elements 29, 30 to the first piston 26 or the second piston 27, so that the pistons 26, 27 move in the movement direction 31 of the conveying movement along the circular path of the conveying chamber 23.

[0055] The process which takes place while the thick matter pump 15 is operating is explained with the help of FIG. 13. In a starting state (FIG. 13A), the second piston 27 is arranged in an intermediate position 32 between the inlet opening 24 and the outlet opening 25 and shuts off the short connecting path between the inlet opening 24 and the outlet opening 25.

[0056] The first piston 26 is coupled with the drive shaft 28, so that it completes a conveying movement in the conveying chamber 23. The conveying movement extends along the long connecting path 33 between the inlet opening 24 and the outlet opening 25. In the state according to FIG. 13A, the first piston 26 has passed over the inlet opening 24. With the further movement of the first piston 26 in the conveying direction, thick matter is conveyed out of the conveying chamber 23 through the outlet opening 25. Parallel to this, thick matter is sucked out of the prefilling container 16, so that the space between the second piston 26 and the inlet opening 24 at the end of the conveying movement is once again filled with thick matter. The sequence of the conveying movement of the first piston 26 is indicated by FIGS. 13A-13C.

[0057] At the end of the conveying movement, the first piston 26 travels over the outlet opening 25 (FIG. 13D), a residual quantity of thick matter is included between the first piston 26 and the second piston 27. The first piston 26 and the second piston 27 are moved together in the conveying direction 31, until the second piston 27 has passed over the inlet opening 24 and the first piston is in the intermediate position 32 between the inlet opening 24 and the outlet opening 25. The thick matter pump is then once again in the initial state according to FIG. 13A, wherein the positions of the pistons 26, 27 are reversed.

[0058] FIG. 4 shows the thick matter pump in a state in which the second piston 27 is arranged in the intermediate position 32 between the inlet opening 24 and the outlet opening 25 and the first piston 26 has covered part of the conveying path. According to the sectional depiction in FIG. 5, the first piston 26 and the second piston 27 are surrounded by a housing 34, wherein a sealing gap is formed between the circumference of the pistons 26, 27 and the housing 34. The housing 34 is interrupted on its outer side by the inlet opening 24 and the outlet opening 25. On the inner side, a circumferential slot 35, through which the connecting elements 29 extend, is formed, via which the pistons 26, 27 are coupled with the drive shaft 28. The connecting elements 29, 30 are configured as disk-shaped elements, so that said connecting elements 29, 30 fill the slot 35 over its entire length.

[0059] In the alternative embodiment according to FIG. 6, the first connecting element 29 is connected to a first wall shell 36, and the second connecting element 30 is connected to a second wall shell 37. The wall shells 36, 37 extend along the inner face of the housing 34, viewed in cross section, and over the entire length of the conveying chamber 23, viewed in the longitudinal direction. Each of the wall shells 36, 37 extends over a circumferential angle 58 of more than 90°. All in all, the two wall shells 36, 37 cover a circumferential angle 58 of more than 180°. A clearance which corresponds to the diameter of the inlet opening 24 and of the outlet opening 25 is contained between the peripheral ends of the wall shells 36, 37. This clearance is necessary so that the thick matter is able to enter the conveying chamber 23, or leave the conveying chamber 23. The internal friction in the thick matter pump is reduced by the wall shells 36, 37 moving along the conveying path together with the thick matter.

[0060] In the other alternative embodiment according to FIG. 7, the housing surrounding the wall shells 36, 37 is dispensed with. The wall shells 36, 37 themselves form the outer end of the conveying chamber 23. The housing is limited to a cylindrical housing part 38 which restricts the outer circumference of the conveying chamber 23. The inlet opening 24 and the outlet opening 25 are formed in the housing part 38.

[0061] According to FIG. 8, a circumferential sealing ring 39 which extends over the entire length of the conveying chamber 23 is arranged between the wall shell 37 and the housing part 38. The conveying chamber is sealed at the transition between the wall shell 37 and the housing part 38 with the sealing ring 39. A second sealing ring 40 seals the transition between the other wall shell 36 and the housing part 38. A third sealing ring 41 is arranged between the connecting elements 29, 30.

[0062] The first piston 26 is provided with a sealing element 42 which extends over a circumferential portion of the piston 26. The sealing element 42 forms a seal between the first piston 26 and the wall shell 37 of the second piston 27.

[0063] An end piece 43 made of hard metal is arranged on a peripheral circumferential portion of the first piston 26. Stones and other granular constituents which become jammed between the piston 26 and an edge of the opening when the passing over the inlet opening 24 or the outlet opening 25 can be broken up by the hard metal end piece 43. The edges of the openings may be formed by corresponding hard metal inserts.

[0064] The hard metal end piece 43 and the sealing element 42 are expendable parts which have to be routinely replaced. The pistons 26, 27 each have an internal cavity 44 which is accessible from outside once the peripheral housing part 38 has been removed. Only the peripheral housing part 38 need therefore be detached, in order to replace the expendable parts, no further dismantling of the thick matter pump is required.

[0065] FIG. 9 shows a possible structural embodiment of the thick matter pump. Two roller bearings 44, 45 are arranged between the frame of the pump, to which the housing part 38 is connected, and the moved parts which turn with the drive shaft 28. A third roller bearing, which is not shown in FIG. 9, may be arranged between the parts moved using the first piston 26 and the parts moved using the second piston 27. A first drive motor 46 drives the first piston 26, a second drive motor 47 drives the second piston 27, as emerges even more clearly from the schematic depiction in FIG. 10.

[0066] In the alternative embodiment according to FIG. 11, both pistons are driven by a shared drive motor 46. The first piston 26 is assigned a dual clutch 47 which couples the first piston either with the drive shaft 28 or with the housing 34. If the first piston 26 is coupled with the drive shaft 28, it follows the rotational movement of the drive shaft 28. If the first piston 26 is coupled with the housing 34, it has a fixed position relative to the housing 34. A corresponding dual clutch 48 is provided for the second piston 27. In the embodiment according to FIG. 12, the drive motor 46 is arranged between the dual clutches 47, 48. The function of the dual clutches 47, 48 is identical.

[0067] In the thick matter pump according to the invention, the conveying flow is interrupted when the pistons 26, 27 move jointly in the conveying direction 31. This is the case in the phase between the state according to FIG. 13D and the state according to FIG. 13A. If a continuous conveying flow is to be achieved, the thick matter pump according to FIG. 14 can be equipped with a supplementary conveying cylinder 49. A transition pipe 50, which creates the connection to the conveying pipe 17, is attached to the outlet opening 25. The supplementary conveying cylinder 49 is attached to the transition pipe.

[0068] A conveying piston 51 of the conveying cylinder 49 is retracted, while thick matter is conveyed through the outlet opening 25 of the thick matter pump. If the conveying flow is interrupted by the outlet opening 25, the conveying piston 51 can be moved forwards again hydraulically, in order to bridge the interruption in the conveying flow. The thick matter pump is therefore capable of conveying liquid concrete in a continuous conveying flow.

[0069] FIG. 15 shows an embodiment of a thick matter pump in which the second connecting path 53 of the conveying cavity 23, which is arranged between the outlet opening 25 and the inlet opening 24, is provided with a shut-off valve 52, which can be moved in a radial direction. In a first state, which is depicted in FIG. 15, the shut-off valve 52 shuts off the second connecting path 53. In a second state, which is not shown, the shut-off valve 52 is moved outwardly, so that the first piston 26 is able to pass through the second connecting path 53.

[0070] The process involved when conveying thick matter corresponds to the embodiment with two pistons 26, 27, subject to the difference that the shut-off valve 52 shuts off the second connecting path 53 during each conveying movement, while the first piston 26 moves along the first connecting path 33 during each conveying movement. In the transitional phase between two conveying movements of the piston 26, the shut-off valve 52 is moved to the side, so that it opens up the second connecting path 53. The piston 26 can pass through the shut-off valve 52 and move on to the next conveying movement.

[0071] In the embodiment according to FIG. 16, the thick matter pump comprises three pistons 26, 27, 56 and two outlet openings 25, 55 which open out into a shared outlet pipe 57. The transitional phase, in which the first piston 26 moves between the second outlet opening 55 and the inlet opening 24, is bridged by the third piston 56 being arranged between the first outlet opening 25 and the second outlet opening 55. Because the second piston 27 has a higher speed than the first piston 26, thick matter is still conveyed through the outlet pipe 57, even though a part of the thick matter conveyed through the first outlet opening 25 flows back through the second outlet opening 55 to the rear side of the first piston 26. As soon as the second piston 27 travels over the first outlet opening 25, the third piston 56 and the second piston 26 are set in motion, so that the second piston 27 initially conveys thick matter with the end of its conveying movement through the second outlet opening 55, while the next conveying movement of the first piston 26, with which the first piston 26 conveys thick matter through the first outlet opening 25, can start in parallel. In this way, the interruption of the conveying flow which occurs with other embodiments of the thick matter pump and which results from two pistons moving together between the outlet opening and the inlet opening, or from the shut-off valve being opened, can be avoided.