CN108779767B

CN108779767B - Method for conveying or transporting fluid or semi-fluid material by means of double-piston pump and double-piston pump thereof

Info

Publication number: CN108779767B
Application number: CN201780018269.4A
Authority: CN
Inventors: 奥托·屈米; 托比亚斯·罗贝尔
Original assignee: Ann Hundred Tuo Drilling Co Ltd
Current assignee: Ann Hundred Tuo Drilling Co Ltd
Priority date: 2016-04-11
Filing date: 2017-04-03
Publication date: 2020-01-21
Anticipated expiration: 2037-04-03
Also published as: WO2017178261A1; EP3232057B1; CA3012564A1; CN108779767A; EP3232057A1; ES2687175T3

Abstract

The invention relates to a method for conveying or transporting fluid or semi-fluid materials, in particular concrete or cement, using a double-piston pump (1), the double-piston pump (1) comprising: two delivery cylinders (3, 4), each of which is arranged with a delivery piston (5, 6) inside, said delivery pistons (5, 6) being movable in an alternating push-pull manner; a feed hopper (7) for receiving material to be conveyed fed by the feed unit; a transfer pipe system (13) comprising a transfer pipe (14), the transfer pipe (14) being connectable to a flow line or a conveying pipe and being able to alternately connect the flow line or the conveying pipe with one of the conveying hydraulic cylinders (3, 4) by means of an articulation device (17), the articulation device (17) comprising two rotating or ram cylinders (45, 47) which can be hydraulically actuated, the rotary movement of the transfer pipe (14) being generated by the rotating or ram cylinders (45, 47); a delivery piston drive mechanism (23) comprising a drive piston (19, 21) for each delivery piston (5, 6) provided in a hydraulic drive system (24), the drive pistons (19, 21) being connected to a dedicated delivery piston (5, 6), wherein both drive pistons (19, 21) are fed by a delivery pump (39) provided in a hydraulic circuit, the feeding being controllable by a valve; and a main control valve (V5) by means of which the alternating hydraulic supply to the respective drive piston (19, 21) is controlled, the method being characterized in that during the rotational movement of the transfer pipe (14) the hydraulic supply to the drive piston (19, 21) is interrupted by means of said main control valve (V5) and the hydraulic circuit of the delivery pump is short-circuited and the output flow of the delivery pump is increased, so that after the rotational movement of the transfer pipe (14) has ended and at the start of the next delivery cycle an increased supply output to the delivery cylinders (5, 6) is performed in a short period, causing a short-term increase of said supplied fluid or semi-fluid material.

Description

Method for conveying or transporting fluid or semi-fluid material by means of double-piston pump and double-piston pump thereof

Technical Field

The present invention relates to a method for transferring or conveying fluid or semi-fluid materials by means of a double-piston pump. Furthermore, the invention relates to a dual piston pump for conveying or transporting fluid or semi-fluid materials, in particular concrete or cement.

Background

Dual piston pumps for the above purposes are well known in the art. According to DE 4215403C 2, a double-piston pump for conveying or transporting fluid or semi-fluid materials, in particular concrete or cement, is known which comprises two transport cylinders, each of which is arranged with a transport piston inside, which transport pistons can be moved in an alternating push-pull manner. The feed hopper is arranged for receiving material to be conveyed fed by the feed unit. The transfer pipe system (S-Weiche) comprises a transfer pipe which can be connected to a flow line or a delivery pipe and which can be alternately connected with one of the delivery hydraulic cylinders by means of an articulation device comprising two rotary or plunger cylinders which can be hydraulically actuated, the rotary movement of the transfer pipe being generated by the rotary or plunger cylinders.

In the hydraulic drive system, a delivery piston drive comprising a drive piston for each delivery piston, which drive piston is connected to a dedicated delivery piston, is provided, wherein both drive pistons are supplied by a delivery pump, which supply can be controlled by a valve. A main control valve is provided by which the alternate supply of hydraulic pressure to the respective drive piston is controlled. In principle, double piston pumps have the disadvantage that during the switching movement of the transfer pipe there are gaps in the conveying or feeding of the fluid or semi-fluid material into the flow line, resulting in feed instability, i.e. pulsation of the material being fed, which is disadvantageous in many fields, in particular in the field of shotcrete for covering tunnel walls.

To compensate for the play in the material required for delivery, the dual piston pump of DE 4215403C 2 proposes a so-called "push over" system. The system provides an additional amount of material delivered at once by increasing the speed of the active delivery piston during the push cycle of the piston.

Although this "push through" system provides better performance of the dual piston pump, some pulsation is still unavoidable. This is caused in particular by the fact that the material is not transported during the changeover of the transfer tube.

DE 9217574U 1 also discloses a system for conveying or delivering fluid or semi-fluid materials with a dual piston pump comprising: two delivery cylinders, each of which is provided with a delivery piston inside, which can move in an alternating push-pull manner; a feed hopper for receiving material to be conveyed fed by a feed unit; a transfer pipe system comprising a transfer pipe connectable to a fluid line or a delivery pipe and capable of alternately connecting the flow line or delivery pipe with one of the delivery hydraulic cylinders by means of an articulation comprising two rotary or plunger cylinders that can be hydraulically actuated, the rotary movement of the transfer pipe being generated by the rotary or plunger cylinders; a delivery piston drive mechanism comprising a drive piston for each delivery piston provided in the hydraulic drive system, said drive piston being connected to a dedicated delivery piston, wherein both drive pistons are supplied by a delivery pump provided in the hydraulic circuit, said supply being controllable by a valve; and a control valve by means of which the alternating hydraulic supply to the respective drive piston is controlled, wherein the control valve is adapted to short-circuit the hydraulic circuit of the delivery pump into the reservoir.

DE 4318267 a1 also shows a double piston pump, in which a hydraulic circuit for driving two rotary or plunger cylinders can be short-circuited between a delivery pump and a reservoir.

Disclosure of Invention

It is therefore an object of the present invention to provide a method for conveying or transporting fluid or semi-fluid materials, in particular concrete or cement, with a double piston pump, which method provides higher performance and in particular reduces the changeover time of the transfer pipe. It is a further object of the invention to provide a double piston pump, in particular a double piston pump for carrying out the method.

According to the invention, during the transition by the rotary movement of the transfer pipe, the hydraulic supply to the drive piston is interrupted by means of the main control valve and the hydraulic circuit of the delivery pump is short-circuited and the output flow of the delivery pump is increased, so that the increased supply output to the delivery cylinder is performed in a short time after the rotary movement of the transfer pipe has ended and at the beginning of the next delivery cycle, thus causing a short-term increase of the supplied fluid or semi-fluid material.

In other words, due to the short circuit of the delivery pump, the hydraulic cylinders driving the pistons are no longer under pressure and the switching action of the transfer pipe can be performed at the highest speed and in the shortest time, and due to the increase of the output flow of the delivery pump, an increased supply of oil is provided to the respective hydraulic cylinders, causing a short-term increase of said supplied fluid or semi-fluid material, so that in operation pulsation of the supplied material is avoided or almost avoided.

According to the invention, after a short increase in the supply output of the delivery pump, said supply output is reduced again to obtain a constant supply of fluid or semi-fluid material.

Furthermore, there is the advantage that the main control valve is controlled by means of an auxiliary or pilot control valve, wherein both the main control valve and the pilot control valve are in a deactivated position or in a neutral position or in an intermediate position during the movement of the transfer pipe.

Another advantage is that each rotary or plunger cylinder includes a movable drive element or plunger that is damped when the drive element or plunger reaches a final displacement position.

The action of the rotary or plunger cylinder is performed in the shortest time and, therefore, at the maximum speed of the drive element or plunger. This results in the need for a quick brake of the movement of the drive element or plunger. The risk of damaging the rotating or plunger cylinder is greatly reduced due to the damping of the movement.

Furthermore, it is advantageous that when braking the movable drive element or plunger of the rotary or plunger cylinder, the movable drive element or plunger is prestressed in the opposite direction, the prestressing providing energy storage, in particular storage of kinetic energy.

Furthermore, there is the advantage that during the next forward or pushing stroke of the displaceable element or plunger of the rotary or plunger cylinder, the stored energy is recovered, so that the recovered energy additionally accelerates the displaceable drive element or plunger. Thus, the time for switching the transfer tubes can be further reduced, so that the negative pulsations of the system are greatly reduced.

The invention also relates to a double piston pump for conveying or transporting fluid or semi-fluid materials, in particular concrete or cement. According to the invention, the double piston pump is characterized in that it is configured such that during the rotary movement of the transfer pipe the main control valve interrupts the hydraulic supply to the drive piston by short-circuiting the hydraulic circuit of the delivery pump, and in that the delivery pump is configured to increase the output flow in a short period after the end of the rotary movement of the transfer pipe and at the beginning of the next delivery cycle.

Furthermore, by this short-term increase of the supplied material, the gap of the transport can be immediately filled and then a rather constant transport of the material without pulsation during the rotational movement of the transfer tube.

It is advantageous that each rotary or plunger cylinder comprises a movable drive element, in particular a plunger, which is movable in a forward or extension stroke and a rearward or retraction stroke, wherein the movable drive element or plunger is damped at least when the end position of the retraction stroke is reached.

Furthermore, each rotary or plunger cylinder comprises a piston filled with gaseous material and a spring pack acting against the piston, thereby causing braking of the movable drive element or plunger, so that the movement of the drive element or plunger can be damped avoiding damage to the transfer pipe system.

Furthermore, it is advantageous that during the braking of the movable drive element or plunger of the rotary or plunger cylinder, the movable drive element or plunger provides a pretension or prestress for the spring set and/or the piston, wherein an energy storage, in particular a storage of kinetic energy, is carried out.

This advantageously leads to the following results: during the next forward stroke of the movable drive element or plunger of the rotary or plunger cylinder, the stored energy is recovered, such that the stored energy additionally accelerates the movable drive element or plunger.

Drawings

Further details, features and advantages will become apparent from the following detailed description or from preferred embodiments of the invention with reference to the accompanying drawings. In the drawings:

FIG. 1 illustrates a perspective view of one embodiment of a dual piston pump according to the present invention;

FIG. 2 shows a block diagram of hydraulic valve block delivery;

FIG. 3 shows a block diagram of a hydraulic valve block of a transfer pipe system (S-Weiche);

FIG. 4 shows a block diagram of a conventional transfer pump system, such as produced by doctor Leisholer (Bosch Rexroth);

FIG. 5 shows a rear view of the transfer pipe system with two rotary or ram cylinders, which is placed in a neutral position during the turning from one transfer cylinder to the other;

FIG. 6 shows a cross-sectional view of the rotary or ram cylinder on the left of FIG. 5 at the beginning of the extension movement, i.e., the retracted position;

fig. 7 shows a sectional view of the rotary or plunger cylinder according to the left side of fig. 6 in its maximum extended position;

fig. 8 shows a sectional view of the rotary or ram cylinder according to the left side of fig. 6 during its retracting movement just before the damping action;

fig. 9 shows a sectional view of the rotary or ram cylinder according to the left side of fig. 6 simultaneously retracted during a damping operation.

In the drawings, like elements are referred to by like reference numerals. The drawings illustrate preferred embodiments of the invention. However, the present invention is not limited to this embodiment and alternative embodiments may also be covered by the description of the present invention.

Detailed Description

Fig. 1 shows a double piston pump 1 in a schematic manner, the basic configuration of which is known in the art. The double piston pump 1 comprises delivery cylinders 3 and 4 in which delivery pistons 5 and 6 are movable, respectively. The double piston pump 1 comprises a feed hopper 7, the feed hopper 7 comprising a housing 10, on the rear side of which housing 10 a rear plate 8 is arranged. According to the feed arrow a9, the material to be dispensed by the double piston pump 1 is fed into the feed hopper 7. Figure 1 does not show the material fed into the feed hopper 7.

On the rear plate 8 is fixed a transfer pipe system (S-Weiche)13, which transfer pipe system 13 comprises transfer pipes 14, which transfer pipes 14 will be alternately connected to the openings 11 connected to the delivery cylinders 3 and to the openings 12 connected to the delivery cylinders 4. According to the double arrow 16, the transfer tube 14 is rotated between the opening 11 and the opening 12 by means of a rotating rod 15, the rotating rod 15 being a formed part of a hinge 17 fixed to the rear plate 8. In fig. 1, the hinge 17 is not fully shown, but is further described with reference to fig. 5 to 9.

As can be seen in fig. 1, the material fed into the feed hopper 7 according to arrow a is sucked into the conveying hydraulic cylinder 4 by the retracting movement of the conveying piston 6, as schematically shown by arrow B.

At the same time, the swivelling levers 15, including the pipe sections 20, are in a position in front of the opening 11, connecting the delivery pipe 14 with the delivery cylinder 3. The transfer piston 5 is moved in a forward direction towards the rear plate 8 so that forward material is fed according to arrow C into a transfer duct (not shown) to be dispensed during operation.

The conveying cylinders 3 and 4 are fixed on one end to the rear plate 8, and the conveying cylinders 3 and 4 are accommodated in the housing 22 at their rear ends. As will be described below and not shown in fig. 1, the delivery pistons 5 and 6 are driven by drive pistons 19 and 21 (see fig. 2), respectively, the drive pistons 19 and 21 being driven by a hydraulic system 24, as shown in fig. 2.

The mode of operation of the double piston pump 1 according to fig. 1 can be described as follows. The conveying piston 5 as shown in fig. 1, during its pumping or conveying stroke, forces material that has been sucked from the feed hopper into the conveying hydraulic cylinder 3 through the opening 11 into the transfer pipe 14 in a forward direction towards the rear plate 8, according to arrow C. In order to provide a connection between the transfer tube 14 and the transport cylinder 3, the articulation 17 rotates the swivelling levers 15 and in particular the tube portion 20 in front of the opening 11 to provide a connection between the transport cylinder 3 and the transfer tube 14.

When the delivery piston 5 has reached its forwardmost position, i.e. all or substantially all the material supplied by the delivery cylinder 3 has been dispensed into the transfer pipe 14, the hinge means 17 are activated to rotate the swivelling levers 15 according to the double arrow 16 to a position covering the openings 12 connected to the delivery cylinder 4, which delivery cylinder 4 is filled with material according to the arrow B by the suction stroke of the delivery piston 6 during the pumping stroke of the delivery piston 5.

During the rotary movement of the swivelling levers 15, a transfer piston drive mechanism 23, which will be described in more detail below with reference to fig. 2, changes the suction stroke of the transfer piston 6 to a push stroke and at the same time the push stroke of the transfer piston 5 to the suction stroke of the transfer piston 5. After the delivery piston 5 has reached the end of the suction stroke and the delivery piston 6 has reached the end of the push stroke, the articulation 17 again moves the swivelling levers 15 from the opening 12 to the opening 11 in order to connect the delivery hydraulic cylinder 3 to the transfer tube 14.

Referring now to fig. 2, fig. 2 shows a delivery piston drive mechanism 23 including a hydraulic drive system 24.

As can be seen in fig. 2, the drive piston 19 as well as the drive piston 21 are conventionally constructed. Both the drive piston 19 and the drive piston 21 have the configuration of a double-acting piston. The drive piston 19 comprises a piston crown 25 accommodated in a cylinder housing 27. A piston rod 29 protrudes from the piston crown 25, and the piston rod 29 is connected to, for example, the delivery piston 5. Similarly, the drive piston 21 includes a piston crown 31 that is housed in a cylinder housing 33. The piston crown 31 is connected to a projecting piston rod 35, the piston rod 35 being connected to, for example, the delivery piston 6. When the hydraulic drive system 24 is actuated, the

pistons

25 and 31 move together with the

piston rods

29 and 35 in the respective directions, so that the delivery pistons 5 and 6 as shown in fig. 1 move in the respective directions.

Referring to FIG. 2, the hydraulic drive system 24 of the present invention will be described in more detail. Line a is a line for feeding oil used for transporting concrete or other materials, and it is connected to a pump. Line B is a line for returning oil to a reservoir (not shown). Valve V3 is a direct acting three-position four-way solenoid directional valve that directs the piloted three-position four-way directional valve V5. Valve V4 is a one-way valve. Valve V5 is the main control valve, valve V5 is hydraulically actuated by valve V3 and includes a locked neutral position. In this intermediate position, line a and line B are short-circuited. Thus, the maximum pump pressure delivered via line a always occurs at valve V5.

The valve V6 is a check valve and serves as a backflow prevention member during operation of the high-pressure pump for clearing swing (rock cleaning). Valve V7 is a capacity control unit for rod side admission and provides a return hydraulic cylinder that is slightly faster than the forward drive cylinder and acts as a compensation for oil delivery losses. The intake stroke of the respective delivery piston 5 or 6 therefore always ends slightly earlier than the thrust stroke of the respective other delivery cylinder 6 or 5. This shows that when the transfer pipe system is switched over, the respective delivery cylinder is fully ready to start the push stroke.

Valve V8 is a one-way valve and acts as a return barrier for the piston rod side oil intake. Valve V9 is a pressure reducing valve for rod side feed and valve V16 is a trim valve for rod side feed a.

The main control valve V5 can be actuated very quickly by the solenoid valve V3 because only a small pressure increase is required. Line T drains control hydraulic fluid from valve V3 to a reservoir (not shown).

When the master pilot operated valve V5 moves rightward, then the drive piston 21 is actuated as the piston 31 is pushed, causing a pushing stroke of the corresponding delivery piston 6. When the pushing stroke of the drive piston 21 is completed, the main control valve V5 is moved to the neutral position, thereby short-circuiting the feed line a and the line B, with the great advantage that full pressure in line a can be obtained when moving the main control valve V5 to the left, so that oil is now fed to the drive hydraulic cylinder 19, immediately starting the movement of the drive hydraulic cylinder 19. During the intermediate position of valve V5, the hydraulic pump is switched to increased pumping power. When the valve V5 is shifted to the next operating position, the increased hydraulic pressure is transmitted to the corresponding forward-driving hydraulic cylinder, causing an increased driving speed of the piston. This causes an increased feeding of material into the transfer tube 14.

Fig. 4 shows a block diagram of a conventional pumping mechanism 39 sold by bosch-li. It can be seen that the pumping mechanism is driven by an electric motor 41. The electric motor 41 drives the pumping action of the oil into line a. Since the pumping system is conventional and does not form part of the present invention, further description of the pumping system is omitted.

Referring now to FIG. 3, the hydraulic system of the transfer pipe system 13(S-Weiche) of the present invention is shown.

The hydraulic system 43 is ready to act on the rotary or ram

cylinders

45 and 47. Those rotary or ram

cylinders

45, 47 are double-acting, as can be seen in fig. 3. However, the rotary or

plunger cylinders

45 and 47 are only schematically illustrated and will be described in more detail below with reference to fig. 6-9.

The components of hydraulic system 43 are as follows. Valve V2 is a one-way valve set as a return obstruction that obstructs reservoir discharge. Valve V3 is an orifice (blend) for controlling the draining of the reservoir when valve V4 is shut off. Valve V4 is a solenoid valve for venting to a reservoir (not shown).

The valve V7 is a pressure reducing valve for reducing the operating pressure for actuating the transfer pipe system 13 as shown in fig. 1. Valve V9 is a pressure control valve for limiting the maximum pressure of the transfer pipe system 13. Unit V10 is a flow control or volume control unit for adjusting the volume of oil used for the cleaning operation.

Valve V12 is a solenoid valve for activating the transfer pipe system 13. Valve V15 is also an orifice (blend) for limiting volume to control valves V24 and V25, respectively. Valve V20 is a double one-way valve that can be unlocked, and valve V20 is actuated during forward drive (forerun) of cylinder B and return stroke of cylinder a. Valve V21 is a double one-way valve that can be unlocked and valve V21 is actuated during forward drive of cylinder a and return stroke of cylinder B. Valve V22 is a double one-way valve that can be unlocked and valve V22 is actuated during forward drive of cylinder B and return stroke of cylinder a. Valve V23 is a double one-way valve that can be unlocked and valve V23 is actuated during forward drive of cylinder a and return stroke of cylinder B. The valve V24 is a solenoid valve for initiating forward drive of the hydraulic cylinder B, and the valve V25 is a solenoid valve for initiating forward drive of the hydraulic cylinder a.

In addition, a hydraulic accumulator 49 is provided to provide a sufficient amount of instantaneous hydraulic power when switching.

The specific configuration of all valves can be derived from the specific notation of the system shown in fig. 2 to 4, but is not limited thereto. Different embodiments giving the same or almost the same effect still fall within the scope of the invention. From fig. 2 to 4, the connecting lines between the components can be clearly derived and are not explained in more detail.

The transfer pipe system 13 is described in more detail with reference to fig. 5. Fig. 5 is a view from behind the feeding funnel 7, fig. 5 showing the transfer pipe system 13 in an intermediate position between the

openings

11 and 12. The tube portion 20 of the swivelling levers 15 is located between the opening 11 and the opening 12 and both the swivelling or

plunger cylinders

45 and 47 are also in an intermediate position. The rotary or

plunger cylinders

45 and 47 will be described in more detail with reference to fig. 6 to 9.

As can be seen from fig. 5, in this embodiment the transfer pipe system 13 comprises a plate 37, the

openings

11 and 12 being located in the plate 37. The transfer pipe system 13 comprises two

arms

51 and 52. The arm 51 is provided with a bearing 54 to pivotably support the rotary or plunger cylinder 45, while the arm 52 is provided with a bearing 56 to pivotably support the rotary or plunger cylinder 47. Both swivel or

plunger cylinders

45 and 47 are pivotally connected at their other ends to a control plate 53, which control plate 53 is in turn connected to the swivelling levers 15 in order to move the swivelling levers 15 from one

opening

11, 12 to the

other opening

12, 11. The connection of the rotary or ram

cylinders

45 and 47 to the hydraulic system 43 that drives both the rotary or ram

cylinders

45 and 47 is not shown in fig. 5. The rear plate as shown in the very schematic fig. 1 is not shown in fig. 5.

Reference is now made to fig. 6 to 9, in which the rotary or plunger cylinder 47 is shown in a partially broken sectional view in different positions during movement in order to provide the required movement of the swivelling levers 15 to connect the transfer tubes 14 alternately with the

openings

11 and 12, respectively. The rotary or plunger cylinder 45 is configured accordingly.

The rotating or ram cylinder 47 includes a cylinder body or housing 55, with a hydraulic oil inlet/outlet 57 disposed in the cylinder body or housing 55 at one end of the partially hollow housing 55 of the rotating or ram cylinder 47. Inside the housing 55, a plunger 59 is provided that is movable within the housing 55.

The plunger 59 is partially formed as a hollow body to accommodate several specific elements therein. A spring pack 61 is provided, for example in the form of stacked coil springs. One object achieved by the invention is to provide a rotary movement of the transfer tube in a minimum time, which can be kept performing a large number of strokes for a long time. Inside the plunger 59, a gas piston 63 filled through a gas inlet/outlet 65 is provided, and a check valve 66 is provided in the gas inlet/outlet 65, wherein gas is introduced into the gas piston 63 through an internal line 67. To seal the plunger 59, a seal 69 is provided and this seal 69 is used to seal against oil leaking out of the housing 55.

Through the opening 71, the housing 55 of the swivel or plunger cylinder 47 can be connected to the arm 52 (see fig. 5), while through the opening 73, the plunger 59 can be connected to the central plate 53.

At the infeed end of the plunger 59, a feed injector 60 is provided, the plunger 59 including an inlet passage including a one-way valve 64. The check valve 64 is partially housed in the front plate 70 to close the hollow plunger 59 at the hydraulic fluid or oil infeed end of the plunger 59. In the retracted position of fig. 6, an oil chamber 68 is provided between the gas piston 63 and the front plate, which oil chamber 68 is filled with oil in this position. The front plate 70 is provided with openings or nuts such as, for example, slot top nuts. To fill the chamber 68 with oil, the oil feed passage 62 passes through the check valve 64, and the check valve 64 prevents oil from escaping from the chamber 68 back into the passage 62.

The rotating or plunger cylinder 47 is shown in four different positions. Fig. 6 shows the fully retracted position prior to the stroke of the plunger 59. Fig. 7 shows the cylinder extended position, in which the plunger 59 has reached its maximum extended position. Fig. 8 shows the position just before the damping operation starts during the retracting movement of the plunger 59, and fig. 9 shows the position when the damping action of the plunger is performed and the gas accumulator for energy recovery is loaded.

In fig. 7, the plunger cylinder 47 is shown in the most extended position of the plunger 59. Oil is fed through the oil inlet 57, forcing the injection portion 60 to move away from the retracted position of the plunger 59. When the plunger 59 moves away from its retracted position shown in fig. 6, the gas piston 63 forces oil out of the chamber 68 to escape to the left of the hollow space through an opening (not shown) in the front plate 70. The gas piston 63 forces oil to escape from the chamber 68 until the gas piston 63 abuts the front plate 70 as shown in fig. 7.

According to fig. 8, the plunger 47 is shown in a position during the retraction movement when the damping action of the plunger 47 is initiated. The injection portion 70 reaches into the oil inlet passage 58 and urges the check valve 64 open. While the oil in chamber 72 is forced to move through the opening of front plate 70 to refill chamber 68, thereby moving gas piston 63 toward spring pack 61. This increases the spring load of the gas piston 63.

Fig. 9 shows the position of the plunger 47 immediately before reaching the retracted end position of fig. 6. Oil chamber 68 is partially filled and oil chamber 72 is further reduced.

In the plunger 47 according to the invention, a damping system is provided which damps the plunger 47 when it is moved into its retracted position and the energy stored by the gas piston 63 during the next stroke of the plunger 47 is used together with the spring pack 21 to accelerate the movement of the plunger 47.

In the present invention, a double-piston pump is provided, by means of which a substantially constant delivery of fluid or semi-fluid material, in particular concrete or cement, is achieved, overcoming the drawbacks of the prior art. In particular, the rotation including the damping system or the very short movement of the

plunger cylinders

45 and 47 prevents the hard abutment of the plunger 59 against the housing 55.

Reference numerals:

1-double piston pump

3-conveying hydraulic cylinder

4-conveying hydraulic cylinder

5-delivery piston

6-delivery piston

7-feed hopper

8-rear plate

9-feed arrow A

10-shell

11-opening

12-opening

13-conveying pipe system (S-Weiche)

14-transfer tube

15-rotating rod

16-double arrow

17-hinge device

19-drive piston

20-pipe subsection

21-drive piston

22-shell

23-conveying piston drive

24-Hydraulic drive System

25-piston top

27-Hydraulic Cylinder housing

29-piston rod

31-piston crown

33-Hydraulic Cylinder housing

35-piston rod

37-plate

39-Pumping mechanism

41-electric motor

43-Hydraulic System

45-rotating or plunger cylinders

47-rotating or plunger cylinders

49-Hydraulic accumulator for providing a sufficient amount of instantaneous hydraulic power at the time of conversion

51-arm

52-arm

53-center plate

54-bearing

55-cylinder body

56-bearing

57-Hydraulic oil Inlet/Outlet

59-plunger

60-feed and discharge injection part

61-spring group

62-inlet channel

63-gas piston

64-one-way valve

65-gas inlet/outlet

66-one-way valve

67-internal gas line

68-oil chamber

69-seal

70-front panel

71-opening

72-oil chamber

73-opening

List of components in the hydraulic circuit:

1.hydraulic drive mechanism (fig. 2):

a: oil inlet for conveying concrete

B: return run of oil from conveying concrete

V3: direct-acting three-position four-way electromagnetic reversing pilot valve for guiding V5

V4: one-way valve

V5: hydraulic start master three-position four-way pilot reversing valve for conveying preselected drive A

V6: backflow prevention element activated during operation of a high pressure pump for clearing oscillations

V7: capacity control unit for rod side admission of oil (return cylinder slightly faster than forward drive cylinder and used to compensate for oil delivery losses)

V8: return barrier for oil inlet at one-way valve and rod side

V9: pressure reducing valve with oil fed from rod side

V16: adjusting valve for rod side oil feed A and for rod side oil feed B

2. Hydraulic drive mechanism of transfer pipe system (fig. 3):

p: pumping line and connection to a fluid pump (not used in the system)

T: connection to return reservoir

V2: check valve for blocking the discharge of the reservoir (return barrier)

V3: throttle (blend) for controlling the discharge of the reservoir when valve V4 is shut

V4: solenoid valve for discharging to a reservoir

V7: pressure relief valve for reducing operating pressure for actuating a transfer pipe system

V9: pressure control valve for limiting the maximum pressure of a transfer pipe system

V10: flow control or volume control unit for regulating the volume of oil for cleaning operations

V12: solenoid valve for activating a transfer pipe system

V15: restriction orifices (blend) for restricting volume to control

valves

24 and 25, respectively

V20: unlockable double check valve actuated during the return stroke of forward-driving cylinder B and cylinder A

V21: unlockable double check valve actuated during forward drive of cylinder A and return stroke of cylinder B

V22: unlockable double check valve actuated during forward drive of cylinder B and return stroke of cylinder A

V23: unlockable double check valve actuated during forward drive of cylinder A and return stroke of cylinder B

V24: solenoid valve for actuating the forward drive of the hydraulic cylinder B

V25: solenoid valve for actuating the forward drive of the hydraulic cylinder A

Claims

1. A method for conveying or transporting fluid or semi-fluid materials, by means of a double-piston pump (1), the double-piston pump (1) comprising:

two delivery cylinders (3, 4), each of which is arranged with a delivery piston (5, 6) inside, said delivery pistons (5, 6) being movable in an alternating push-pull manner;

a feed hopper (7), the feed hopper (7) for receiving material to be conveyed fed by a feeding unit;

a transfer pipe system (13), the transfer pipe system (13) comprising a transfer pipe (14), the transfer pipe (14) being connectable to a flow line or a conveying pipe and being able to alternately connect the flow line or the conveying pipe with one of the two conveying hydraulic cylinders (3, 4) by means of an articulation device (17), the articulation device (17) comprising two rotating ram cylinders (45, 47) which can be hydraulically actuated, the rotational movement of the transfer pipe (14) being generated by the rotating ram cylinders (45, 47);

a delivery piston drive mechanism (23), the delivery piston drive mechanism (23) comprising a drive piston (19, 21), the drive piston (19, 21) being used to drive each delivery piston (5, 6) provided in a hydraulic drive system (24), the drive piston (19, 21) being connected to the dedicated delivery piston (5, 6), wherein both drive pistons (19, 21) are hydraulically supplied by a delivery pump (39) provided in a hydraulic circuit, the hydraulic supply being controllable by a valve; and

a main control valve (V5) by which alternating hydraulic supply to the respective drive piston (19, 21) is controlled,

the method is characterized in that it consists in,

during the rotational movement of the transfer tube (14):

-interrupting the hydraulic supply to the drive pistons (19, 21) and short-circuiting the hydraulic circuit of the delivery pump by means of the main control valve (V5), and

-increasing the output flow of the delivery pump,

such that an increased feed output of the feed delivery cylinders (3, 4) is performed in a short period after the rotary movement of the transfer pipe (14) has ended and at the beginning of the next delivery cycle, thereby causing a short-term increase in the fluid or semi-fluid material being fed.

2. The method of claim 1, wherein the supply output of the delivery pump is decreased again after a short-term increase in the supply output.

3. Method according to claim 1 or 2, characterized in that the main control valve (V5) is controlled by means of a pilot control valve (V3), wherein during the movement of the transfer pipe (14) both the main control valve (V5) and the pilot control valve (V3) are in a deactivated position.

4. A method according to claim 1 or 2, characterized in that each rotating ram cylinder (45, 47) comprises a movable drive element, which is damped when it reaches a final displacement position.

5. Method according to claim 4, characterized in that the movable drive element of the rotating ram cylinder (45, 47) is prestressed in the opposite direction when braking it, said prestressing providing energy storage.

6. The method according to claim 5, characterized in that during the next forward stroke of the movable drive element of the rotating ram cylinder (45, 47), the stored energy is recovered such that the recovered energy additionally accelerates the movable drive element.

7. A method according to claim 1 or 2, wherein the fluid or semi-fluid material is concrete or cement.

8. The method of claim 4, wherein the movable drive element is a plunger (59).

9. The method of claim 5, wherein said energy storage provided by said pre-stressing is storage of kinetic energy.

10. A dual piston pump (1), the dual piston pump (1) being for conveying or transporting fluid or semi-fluid material, the dual piston pump (1) comprising:

it is characterized in that the preparation method is characterized in that,

the double piston pump (1) is configured such that during the rotary movement of the transfer pipe (14), the main control valve (V5) interrupts the hydraulic supply to the drive pistons (19, 21) by short-circuiting the hydraulic circuit of the delivery pump; and is

The delivery pump is configured to increase the output flow rate in a short period after the end of the rotational movement of the transfer tube (14) and at the beginning of the next delivery cycle.

11. The double piston pump (1) according to claim 10, characterized in that the main control valve (V5) is hydraulically actuatable by means of a pilot control valve (V3).

12. The double piston pump (1) according to claim 10 or 11, wherein each rotating piston cylinder (45, 47) comprises a movable drive element which is movable in a forward or extension stroke and a rearward or retraction stroke, wherein the movable drive element is damped at least when an end position of the retraction stroke is reached.

13. The double piston pump (1) according to claim 12, characterized in that each rotating plunger cylinder (45, 47) comprises a piston (63) filled with gaseous material and a spring pack (61) acting against the piston (63) causing braking of the movable drive element.

14. The double piston pump (1) according to claim 13, characterized in that during braking of the movable drive element of the rotating piston cylinder (45, 47), the movable drive element provides a prestress to the spring pack (61) and/or the piston (63), wherein energy storage is performed by the prestress.

15. The double piston pump (1) according to claim 14, characterized in that during the next forward stroke of the movable drive element of the rotating piston cylinder (45, 47), the stored energy is recovered, so that the stored energy additionally accelerates the movable drive element.

16. The double piston pump (1) according to claim 10, characterized in that the fluid or semi-fluid material is concrete or cement.

17. The dual piston pump (1) according to claim 12, wherein the movable drive element is a plunger (59).

18. The double piston pump (1) according to claim 14, wherein the energy storage performed is a storage of kinetic energy.