EP3488104B1 - Viscous material pump - Google Patents

Description

The invention relates to a thick matter pump with a first delivery cylinder, a second delivery cylinder and an additional cylinder. The additional cylinder is designed to bridge a delivery gap between the first delivery cylinder and the second delivery cylinder. The thick matter pump comprises a movable pipe section which forms a connection between the first delivery cylinder and an outlet of the thick matter pump in a first state and which forms a connection between the second delivery cylinder and the outlet of the thick matter pump in a second state.

Such pumps are used to convey thick materials such as fresh concrete or mortar. The feed cylinders suck the thick material out of a supply with a backward movement. With a forward movement, the thick matter is conveyed in the direction of an outlet of the thick matter pump.

With the movable pipe section, the feed cylinders are alternately connected to the outlet of the thick matter pump. The other feed cylinder is not connected to the outlet in this phase, but can suck in thick matter from the supply with the backward movement.

When the forward movement of the first delivery cylinder is finished, the movable pipe section is switched to the second delivery cylinder. During the transition from the first delivery cylinder to the second delivery cylinder, the material flow is interrupted due to the change between the delivery cycles of the delivery cylinders.

With the additional cylinder, the transition between the two delivery cylinders is bridged by the additional cylinder conveying thick material in the direction of the pump outlet while the pipe section is being switched over. This makes it possible to generate an essentially continuous flow of material towards the pump outlet, see eg documents US 3,663,129 A , DE 42 08 754 A1 and US 3,963,385 A . This can cause the material conveyed by the additional cylinder to flow back into one of the conveying cylinders.

The object of the invention is to present a thick matter pump with which a uniform material flow in the direction of the pump outlet can be generated. Starting from the prior art mentioned, the object is achieved with the features of claim 1. Advantageous embodiments are specified in the subclaims.

According to the invention, the movable tube section comprises a switchable closure which is arranged between an input end of the movable tube section and the additional cylinder.

By integrating a switchable closure in the movable pipe section, the path from the additional cylinder to the delivery cylinders can be closed when the additional cylinder conveys thick material. A backflow from the additional cylinder in the direction of the feed cylinder can be prevented in this way.

The movable tube section may extend from the inlet end to an outlet end. The information inlet and outlet refer to the direction of movement of the material flow which is started by the forward movement of a conveying cylinder. The movable pipe section can be rigid, so that the inlet end and the outlet end are in a fixed spatial To be related to each other. Embodiments are also possible in which the pipe section is movable in itself, ie in which the position of the inlet end can be moved relative to the position of the outlet end.

The pipe section can be movably supported relative to a support structure of the thick matter pump. The bearing can comprise a rotary bearing about which the pipe section can be rotated. The pivot bearing can be aligned concentrically with an outlet end of the pipe section. An end face of the tube section forming the outlet end can be aligned perpendicular to the axis of rotation. As a result, the pipe section can be coupled to a connecting pipe arranged in a fixed position, regardless of its rotational position.

The inlet end of the pipe section can be arranged offset in the radial direction with respect to the axis of the rotary bearing. The inlet end of the pipe section then changes position as the pipe section is rotated. With a suitable arrangement of the delivery cylinders, the inlet end can be coupled to the first delivery cylinder or to the second delivery cylinder by rotating the pipe section. An end face of the tube section forming the inlet end can be aligned perpendicular to the axis of rotation.

The pipe section can comprise a branch leading to the additional cylinder, so that the additional cylinder is accessible from the interior of the pipe section. With a forward movement of the additional cylinder, it is therefore possible to set a material flow of the thick material in the pipe section in motion or to keep it in motion. By arranging the branch in the movable pipe section, there are short paths between the feed cylinders, the additional cylinder and the switchable closure, which is advantageous for generating a continuous material flow.

Thick matter is a generic term for media that are difficult to convey. The thick material can be, for example, a material with coarse-grained components, a material with aggressive components or the like. The thick matter can also be a bulk material. In one embodiment, the thick material is fresh concrete. Fresh concrete can contain grains up to a size of more than 30 mm, sets, forms deposits in dead spaces and is therefore difficult to promote.

Since the switchable closure is a component of the movable tube section, the movable tube section can be switched over without changing the switching position of the closure. In particular, the pipe section can comprise a first section which extends between the inlet end and the closure, and a second section which extends between the closure and the branch. The closure can be switchable, so that in a first state it enables the material flow from the feed cylinder to pass in the direction of the outlet end of the pipe section and in a second state it prevents the material from flowing back from the branch in the direction of the inlet end.

The closure can comprise a locking slide which releases the cross section of the tube in a first position and closes the tube in a second position. The locking slide can be rotatably mounted with respect to a pivot axis, so that it can switch between the two positions by rotating about the pivot axis. For simple actuation of the locking slide, it can be advantageous if the pivot axis of the slide coincides with the axis of rotation of the pipe section. Other mechanisms for moving the slide are also possible. For example, the locking slide can be moved translationally to close between the two positions switch. Combinations of rotary and translatory movements are also possible. In all cases, the movement can take place in the plane of the locking slide.

Embodiments are included in the invention in which the additional cylinder is fixedly connected to the movable tube section. In such embodiments, the auxiliary cylinder also moves when the pipe section is moved. In order to keep the moving masses low, it can be advantageous if the additional cylinder is connected to the support structure of the thick matter pump, so that the pipe section can be moved independently of the additional cylinder.

The thick matter pump according to the invention can be set up in such a way that the connection between the interior of the pipe section and the additional cylinder is maintained in every rotational position which the pipe section assumes when the pump is in operation. With the additional cylinder, thick matter can then be conveyed in the direction of the outlet end of the pump regardless of the rotational position of the pipe section. In particular, the pipe section can have an opening which is coaxial with the axis of rotation of the pipe section and to which the additional cylinder connects.

The movable pipe section may form a straight path that extends from an opening facing the auxiliary cylinder to the outlet end of the pipe section. The straight path can extend parallel to the axis of rotation of the pipe section and in particular be coaxial to the axis of rotation. The coaxial arrangement has the advantage that the forces acting on the pipe section are low, while the pipe section is rotated about the axis of rotation and while the additional cylinder conveys material through the pipe section.

The path coming from the inlet end can enclose an angle with the branch leading to the additional cylinder, which is less than 90 °, preferably less than 60 °, more preferably less than 45 °. Such an acute angle has the advantage that the material flows coming from the additional cylinder and the delivery cylinders can be well combined to form a common material flow.

The thick matter pump according to the invention can be set up in such a way that the two delivery cylinders are actuated in opposite directions. This means that the forward movement of a piston arranged in the one delivery cylinder takes place at the same time as the backward movement of a piston arranged in the other delivery cylinder. In particular, the opposing movements can be synchronized. The forward movement of the one delivery cylinder can begin at the same time as the backward movement of the other delivery cylinder begins. The forward movement of the one delivery cylinder can end at the same time as the backward movement of the other delivery cylinder ends. The amount of speed can be the same at any time.

The actuation of the feed cylinder can be coordinated with the movement of the pipe section. Thus, the pipe section can be connected to the first feed cylinder when the forward movement of the first feed cylinder takes place. In this first state, access to the second feed cylinder can be free, so that the second feed cylinder can suck thick matter from the supply with its backward movement. The pipe section may be connected to the second feed cylinder when the forward movement of the second feed cylinder takes place. In this second state, access to the first feed cylinder can be free, so that the backward movement of the first feed cylinder can draw in thick matter from the supply.

The closure with which backflow from the additional cylinder in the direction of the delivery cylinder is prevented can also be matched to the delivery cylinder or to the pipe section. In particular, the closure can be switched so that it allows free passage through the pipe section when either the first delivery cylinder or the second delivery cylinder is in the forward movement.

The closure can close the pipe section between the inlet end and the branch, while the pipe section is switched between the first delivery cylinder and the second delivery cylinder. There may be a period of time during the switching of the pipe section in which the piston of the first delivery cylinder and / or the piston of the second delivery cylinder are at rest. The time span can extend over the entire duration of the switching process.

The feed cylinder to which the pipe section is coupled after switching can build up pressure with an initial forward movement of the piston before the closure is switched. This can reduce the pressure difference that is present across the closure during switching.

The auxiliary cylinder can be set up so that it performs a forward movement while the closure is in the closed state. In particular, the forward movement can extend over the entire period in which the closure is in the closed state. The beginning of the forward movement of the auxiliary cylinder can overlap with the end of the forward movement of a feed cylinder. The end of the forward movement of the auxiliary cylinder may overlap with the beginning of the forward movement of the other feed cylinder. The additional cylinder and the feed cylinder can be coordinated in such a way that the total amount of material conveyed is almost constant over time. A constant flow of material can then be conveyed towards the pump outlet. In particular, the speed of the forward movement can be reduced in both the additional cylinder and the delivery cylinders if another cylinder is in the forward movement.

An active drive can be provided for the forward movement of the piston arranged in the additional cylinder, for example in the form of a hydraulic drive. The piston can also be moved backwards by the active drive. It is also possible that the piston is moved back passively by the pressure of the material in the pipe section. The additional cylinder is then fed by a material flow generated by the feed cylinders. With the first delivery cylinder and the second delivery cylinder, both the forward movement and the backward movement can be actively driven. The drive can be a hydraulic drive, for example.

The movable tube section can extend through a prefill container. When the pump is operating, as much thick matter can be continuously refilled into the prefilling container as is conveyed towards the pump outlet with the delivery cylinders. During the backward movement, the delivery cylinders can be connected to the prefill container so that they can suck thick matter out of the prefill container.

In particular, the inlet end of the pipe section can be arranged within the prefilling container. The outlet end of the pipe section can be arranged inside or outside of the prefilling container. The movable pipe section can be supported with two pivot bearings. The route between the two Rotary bearings can extend through the prefill container. The drive for the movement of the pipe section and / or the drive for the movement of the closure can be arranged outside the prefilling container. In particular, one of the drives can be arranged on one side of the prefill container and the other drive on the other side of the prefill container.

The drive for the switchable closure can be supported on a structure of the thick matter pump, so that the closure can be moved relative to the structure by the drive. This structure can be the carrying structure of the thick matter pump. If the switching state of the closure is to remain unchanged when the movable tube section is switched over, the drive of the switchable closure can be carried passively when the tube section is moved.

Alternatively, the drive for the switchable closure can be supported on a structure that belongs to the movable tube section. When the pipe section is switched over, the switchable closure and its drive are moved as a whole, so that when the movable pipe section is switched over, the switching state of the closure and the state of the associated drive remain unchanged. This reduces the mechanical effort, but more mass has to be moved when switching the pipe section.

The drive of the switchable closure can be set up so that it is only actuated when the movable pipe section is at rest. It is also possible for the switching movement of the closure to be superimposed on the switching movement of the movable tube section.

The prefilling container and the delivery cylinder can be connected to the support structure of the thick matter pump, so that they are in a fixed spatial relationship to one another. The feed cylinders can be aligned parallel to one another and arranged at the same height. The orientation of the delivery cylinder can be parallel to the axis of rotation of the pipe section. The axis of rotation of the pipe section can be arranged centrally between the delivery cylinders and above the delivery cylinders. The additional cylinder can be arranged parallel to the feed cylinders.

The thick matter pump can comprise exactly two delivery cylinders. It is then switched alternately from the first to the second delivery cylinder and from the second to the first delivery cylinder. If the thick matter pump comprises more than two delivery cylinders, the movable pipe section can be cyclically switched between the delivery cylinders. In all cases, the additional cylinder can be set up so that it bridges each of the transitions.

The term delivery cylinder is to be understood functionally. The invention also encompasses embodiments in which the two delivery cylinders are combined in one physical cylinder in the sense of the invention, either two pistons moving in the same cylinder or one piston performing a forward movement in both directions of movement in accordance with the invention. In a preferred embodiment, the pump comprises two physically separate cylinders which form the two delivery cylinders.

The movable pipe section and the additional cylinder can be elements of a structural unit which is detachably connected to the thick matter pump. Maintenance and cleaning of the thick matter pump according to the invention can thereby be facilitated.

The thick matter pump can comprise an alternative operating mode in which only the two delivery cylinders are in operation while the additional cylinder is not in operation. This operating mode can be an emergency operation.

Fig. 1:

ein mit einer erfindungsgemäßen Dickstoffpumpe ausgestattetes Fahrzeug;

Fig. 2:

eine schematische Darstellung einer erfindungsgemäßen Dickstoffpumpe;

Fig. 3 bis 6:

eine schematische Darstellung verschiedener Betriebszustände der erfindungsgemäßen Dickstoffpumpe; und

Fig. 7:

ein Taktdiagramm verschiedener Komponenten der erfindungsgemäßen Dickstoffpumpe.

The invention is described below with reference to the accompanying drawings using exemplary embodiments. Show it:

Fig. 1:

a vehicle equipped with a thick matter pump according to the invention;

Fig. 2:

a schematic representation of a slurry pump according to the invention;

3 to 6:

a schematic representation of different operating states of the thick matter pump according to the invention; and

Fig. 7:

a timing diagram of various components of the slurry pump according to the invention.

On the back of one in Fig. 1 shown truck 14, a thick matter pump 15 is arranged in the form of a concrete pump. The thick matter pump 15 comprises a prefilling container 16, into which the concrete is filled from a supply (not shown). The thick matter pump 15 sucks the concrete out of the prefilling container and conveys the concrete through a connecting pipe 17 which extends along a distribution boom 18. The placing boom 18 is mounted on a slewing ring 19 and can be folded out over several joints, so that the end of the tube 17 can be brought into a position spaced apart from the truck 14. In this position, the concrete is brought out of the connecting pipe 17. Embodiments that are arranged on a stationary frame (not shown) are also included.

According to Fig. 2 The thick matter pump 15 comprises a first feed cylinder 20, a second feed cylinder 21 and an additional cylinder 22 adjacent to the prefilling container 16. A movable pipe section 24 extends between the connecting pipe 17, which is connected to the outlet of the thick matter pump, and the feed cylinders 20, 21. The movable pipe section 24 comprises an outlet end 23 which is arranged coaxially to the connecting pipe 17 and which is connected to the connecting pipe 17 via a rotary bearing. The pivot bearing defines an axis of rotation about which the pipe section 24 can be rotated.

The inlet end 25 of the movable tube section 24 is spaced radially from the axis of rotation. The position of the inlet end 25 is therefore changed when the movable tube section 24 is rotated about the axis of rotation. In a first rotational position of the pipe section 24, the inlet end 25 is aligned with the first delivery cylinder 20. In a second rotation position of the pipe section 24, the inlet end 25 is aligned with the second delivery cylinder 21. The other delivery cylinder is accessible from the prefilling container 16.

In the in Fig. 2 In the state shown, the first delivery cylinder 20 can suck concrete out of the prefilling container 16 with a backward movement of its piston. With a forward movement of its piston, the second delivery cylinder 21 can deliver concrete located in the interior of the delivery cylinder 21 through the pipe section 24 into the connecting pipe 17. After the end of the forward movement of the second delivery cylinder 21, the movable pipe section 24 is switched over so that the inlet end 25 is connected to the first delivery cylinder 20 and that the second delivery cylinder 21 is open to the prefilling container 16. The first delivery cylinder 20 can then convey concrete through the pipe section 24 into the connecting pipe 17 with a forward movement, while the second delivery cylinder 21 with a backward movement concrete sucks from the prefill 16.

During the switching process by which the movable pipe section 24 is switched between the two delivery cylinders 20, 21, neither of the two delivery cylinders 20, 21 can deliver concrete into the pipe section 24. In order to prevent an interruption of the material flow in this phase, the thick matter pump according to the invention is equipped with the additional cylinder 22. The additional cylinder 22 is connected to a branch 26 of the movable pipe section 24, so that the additional cylinder 22 can convey concrete through the pipe section 24 into the connecting pipe 17 with a forward movement of its piston. The additional cylinder 22 thus bridges the phase in which none of the delivery cylinders 20, 21 can convey concrete into the connecting pipe 17, so that the continuous flow of material in the direction of the connecting pipe 17 can also be maintained in this phase.

In order to prevent the concrete conveyed by the additional cylinder 22 from flowing back in the direction of the conveying cylinders 20, 21, the movable pipe section 24 is equipped with a locking slide 27. The locking slide 27 is arranged between the branch 26 and the inlet end 25 of the movable tube section 24. The gate valve 27 is switched so that it clears the way through the pipe section 24 when one of the feed cylinders 20, 21 makes a forward movement, and that it blocks the way through the pipe section 24 when switching between the feed cylinders 20, 21 . In this phase, concrete can be conveyed in the direction of the connecting pipe 17 with the additional cylinder 22.

A possible process sequence in the operation of the pump according to the invention is described below using the Figures 3 to 7 explained. In Figure 7A is the speed V of the movement of the first feed cylinder 20 plotted over time T. In the Figures 7B and 7C the movement of the second delivery cylinder 21 and the additional cylinder 22 is shown accordingly. A forward movement is in 7A to 7C represented by a value above the zero line, a value below the zero line corresponds to a backward movement.

In Figure 7D the movement of the locking slide 27 is shown in FIG Figure 7E the movement of the movable pipe section 24. The representation in the Figures 7D and 7E is not direction-dependent, both switching directions are represented by a value above the zero line.

The state according to Fig. 3 corresponds to phase 40 in Fig. 7 . The piston of the first delivery cylinder 20 ( Figure 7A ) performs a forward movement while the piston of the second feed cylinder 21 ( Figure 7B ) makes a backward movement. The locking slide 27 ( Figure 7D ) is switched so that the path through the pipe section 24 is free. The pipe section 24 ( Figure 7E ) is coupled to the first feed cylinder 20.

In phase 40, the first delivery cylinder 20 conveys concrete through the pipe section 24 to the connecting pipe 17. The second delivery cylinder 21 sucks in concrete from the prefilling container 16, so that the interior of the second delivery cylinder is filled with concrete. The piston of the additional cylinder 22 is pushed backward by the pressure applied within the pipe section 24. The additional cylinder 22 therefore performs a backward movement ( Figure 7C ) and thus also takes concrete into its interior.

In phase 41, the first delivery cylinder 20 ( Figure 7A ) shortly before the end of its forward movement, the speed of the forward movement is reduced to half. The material flow conveyed with the first feed cylinder 20 is reduced yourself. At the same time, the additional cylinder 22 ( Figure 7C ) set in a forward movement at a reduced speed so that the material flow remains the same overall.

At the end of phase 41, the locking slide 27 is actuated so that it blocks the path through the pipe section 24 in phase 42. The forward movement of the first delivery cylinder 20 ends and the first delivery cylinder 20 remains at rest in phase 42. The additional cylinder 22 ( Figure 7C ) is driven forward at increased speed in phase 42, so that it alone maintains the desired material flow. The movable pipe section 24 ( Figure 7E ) is switched from the first feed cylinder 20 to the second feed cylinder 21 in phase 42. The Fig. 4 shows the state shortly before switching the pipe section 24, in which the locking slide 27 has already been switched, but the pipe section 24 is still connected to the first feed cylinder 20.

After the pipe section 24 is switched to the second delivery cylinder 21, the forward movement of the second delivery cylinder 21 begins in phase 43 ( Figure 7B ). This state of the pump, in which the forward movement of the second delivery cylinder 21 begins, but the locking slide 27 is still closed, is in Fig. 5 shown. As soon as the second delivery cylinder 21 has built up a first pressure, the locking slide 27 ( Figure 7D ) actuated so that it clears the way through the pipe section 24 again. The second feed cylinder 21 and the additional cylinder 22, both of which are moved forward at a reduced speed, jointly generate the desired material flow in the direction of the tube 17.

In phase 44, the second delivery cylinder 21 moves forward at full speed, causing the additional cylinder 22 to move backwards. At the same time, the first feed cylinder sucks concrete with a backward movement from the prefill container 16, see Fig. 6 . Phase 44 thus corresponds to phase 40, the states of the first delivery cylinder 20 and the second delivery cylinder 21 being interchanged.

The forward movement of the second feed cylinder 21 ends in phase 45, in which the piston of the second feed cylinder 21 is moved forward at a reduced speed. At the same time, the additional cylinder 22 is moved forward at a reduced speed, so that the material flow remains unchanged. At the end of phase 45, the locking slide 27 is actuated, so that in phase 46, in which the two delivery cylinders 20, 21 are at rest, the pipe section 24 can be switched back to the first delivery cylinder 20. The process begins again after the locking slide 27 is opened again.

This sequence is based on the following structure of the thick matter pump according to the invention. The branch 26 of the pipe section 24 leading to the additional cylinder 22 is arranged coaxially to the axis of rotation of the pipe section 24. The extension cylinder 22 is arranged in the extension of the branch 26. The pipe section 24 is supported by a first rotary bearing, which is arranged at the outlet end 23 of the pipe section 24, and by a second rotary bearing, which is arranged between the branch 26 of the pipe section 24 and the additional cylinder 22. The pipe section 24 extends through the prefilling container 16 between the two pivot bearings. The locking slide 27 is supported by another coaxial rotary bearing. The rotary bearing of the locking slide 27 is connected to the branch 26 of the pipe section 24, so that the position of the locking slide 27 in the pipe section 24 remains unchanged when the pipe section 24 is rotated.

The tube section 24 is actuated by a drive which is arranged in a housing part 28 of the prefilling container. According to 3 to 6 two hydraulically operated cylinders 29, 30 which engage a lever of the pipe section 24. By extending one cylinder and retracting the other cylinder, the pipe section 24 is rotated about the axis of rotation. The drive 29, 30 is arranged viewed from the prefill container 16 in the direction of the rear of the vehicle.

The drive for the blocking slide 27 is arranged on the other side of the prefilling container 16. The drive also comprises two hydraulically actuated cylinders 31, 32, which engage a lever of the locking slide 27. The hydraulically actuated cylinders 31, 32 are moved passively when the pipe section 24 is rotated. By actively actuating the cylinders 31, 32, the locking slide 27 is moved relative to the pipe section 24. The drive 31, 32 is arranged viewed from the prefill container 16 in the direction of the vehicle front.

The housing part 28 of the prefilling container 16 forms, together with the movable pipe section 24, the locking slide 27, the two drives 29, 30, 31, 32 and the additional cylinder 22, a structural unit which can be detached overall from the thick matter pump. This enables easy cleaning and maintenance of the pump.

Claims (15)

1. Thick material pump having a first delivery cylinder (20), a second delivery cylinder (21) and an additional cylinder (22) for bridging a transition between the first delivery cylinder (20) and the second delivery cylinder (21), and having a movable tube section (24) which, in a first state, forms a connection between the first delivery cylinder (20) and an outlet (23) of the thick material pump, and which in a second state forms a connection between the second delivery cylinder (21) and the outlet (23) of the thick material pump, characterized in that the movable tube section (24) comprises a switchable closure (27) which is arranged between an inlet end of the movable tube section (24) and the additional cylinder (22) .
2. Thick material pump according to Claim 1, characterized in that the tube section (24) is mounted so as to be rotatable about a rotational axis, and in that the rotational axis is oriented concentrically with respect to an outlet end (23) of the tube section (24).
3. Thick material pump according to Claim 1 or 2, characterized in that the closure (27) comprises a gate valve which can be moved in a translatory and/or rotary fashion.
4. Thick material pump according to one of Claims 1 to 3, characterized in that the closure (27) is pivotable, wherein the pivoting axis is oriented coaxially with respect to the rotational axis of the movable tube section (24).
5. Thick material pump according to Claim 3 or 4, characterized in that the closure (27) is opened if one of the delivery cylinders (20, 21) is moving forward, and in that the closure (27) is closed if the movable tube section (24) is switched over between the delivery cylinders (20, 21).
6. Thick material pump according to one of Claims 3 to 5, characterized in that the delivery cylinder (20, 21) to which the tube section (24) is coupled after the switching over of the tube section (24) builds up a pressure with an initial forward movement of the piston before the closure (27) is switched over.
7. Thick material pump according to one of Claims 1 to 6, characterized in that the delivery cylinders (20, 21) are at rest while the tube section (24) is switched over.
8. Thick material pump according to one of Claims 1 to 7, characterized in that the tube section (24) comprises a branch (26) which leads off to the additional cylinder (22).
9. Thick material pump according to Claim 8, characterized in that the additional cylinder (22) is arranged coaxially with respect to the rotational axis of the tube section (24).
10. Thick material pump according to one of Claims 1 to 9, characterized in that the movable tube section (24) extends through a pre-filling container (16) of Thick material pump.
11. Thick material pump according to Claim 10, characterized in that a drive for moving the tube section (24) is arranged on the one side of the pre-filling container (16), and a drive for moving the closure (27) is arranged on the other side of the pre-filling container (16).
12. Thick material pump according to one of Claims 1 to 11, characterized in that a flow of material coming from the delivery cylinders (20, 21) and a flow of material coming from the additional cylinder (22) are combined at an angle of less than 90°, preferably less than 60°, more preferably less than 45°.
13. Thick material pump according to one of Claims 1 to 12, characterized in that the forward movement of the additional cylinder (22) overlaps with the end of the forward movement of the one delivery cylinder (20, 21) and with the start of the forward movement of the other delivery cylinder (20, 21).
14. Thick material pump according to one of Claims 1 to 13, characterized in that the additional cylinder (22) is fed by a flow of material which is generated by the delivery cylinders (20, 21) .
15. Thick material pump according to one of Claims 1 to 14, characterized in that the movable tube section (24) and the additional cylinder (22) are elements of one unit which is detachably connected to the thick material pump.

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