EP2761190A2 - Hydraulic system with suction/return filter - Google Patents

Abstract

The invention relates to a hydraulic system, preferably for piloting and actuating a two-cylinder thick matter pump. The hydraulic system comprises a tank (68) for receiving hydraulic oil, a primary circuit having at least one hydraulic consumer (AH, MH) which has at least one primary pump (36, 38, 61, 70), which is loaded with hydraulic oil via a first suction line (42), and is connected on the outlet side to at least one first return line, and which has a suction/return filter (40) which communicates with the first suction line (42) on the outlet side and is loaded on the inlet side with return oil from the at least one return line. A special feature of the invention consists in that the first suction line (42) communicates with the tank (68) via a separate replenishing suction line (86) and a suction filter (66), wherein a replenishing suction valve (88) which is preloaded in the direction of the suction filter (66) is arranged in the replenishing suction line (86).

Description

 The invention relates to a hydraulic system, preferably for controlling and actuating a mobile thick matter pump, having a tank under atmospheric pressure for receiving hydraulic oil, with a at least one hydraulic consumer driving primary circuit, the at least one motor-driven input side via a first suction line acted upon with hydraulic oil, on the output side to a at least one first return line connected hydraulic primary pump and an output side communicating with the suction line and the input side with return oil from the at least one return line acted suction return filter and with a branched off from the first suction line, about a bias valve in the tank opening branch line.

The invention differs from conventional thick matter pumps in that the suction line to the primary pump and the returns from the primary circuit do not open into the tank, but that the suction line communicates with the outlet side of the suction / return filter, while the return lines to the inlet side of the suction Return filters are connected. This so-called suction-return filter system requires an excess amount of oil to z. B. compensate for leakage oil, which are led directly to the tank, or to compensate for short-term missing oil volumes in the return due to the compressibility of the hydraulic oil on the pressure side. Accordingly, a secondary circuit is proposed according to the invention, which has at least one motor-driven, acted upon by a second suction line with hydraulic oil, output connected to at least one second return line hydraulic secondary pump, the second suction preferably communicates via a suction filter with the tank and the second return line either flows into the tank or the input side is connected to the suction-return filter. The Ver- remaining excess oil in the suction-return filter system is fed to the tank via the preload valve.

The suction / return filter system ensures that the surplus oil quantity in conjunction with the preload valve results in optimum suction conditions for the primary pumps connected to the first intake line in the primary circuit, that the cold start behavior is improved by the preload and that the fuel passing through the tank Guided oil quantity is significantly reduced, so that a much smaller tank volume and thereby a weight reduction and a cost reduction during oil change is possible.

However, it has been shown that in the case of thick matter pumps by the operation of consumers with differential cylinders, z. B. when extending the vehicle support or when extending the mast to a significant undersupply in the suction-return filter system can come.

In order to avoid this disadvantage, it is further proposed according to the invention that the first suction line communicates with the tank via a separate, large-sized suction line and a further suction filter and that a suction-suction valve biased in the direction of the further suction filter is arranged in the suction line.

As a further suction filter while the suction filter can be used in the second suction line. A preferred embodiment of the invention provides that in at least one of the return lines, an oil cooler is arranged. This is especially important when it comes to heating the hydraulic oil during operation. It is further proposed according to a preferred embodiment of the invention that in at least one of the input side connected to the suction-return filter return lines, a check valve is arranged. A preferred embodiment of the invention provides that at least one of the primary pumps in the primary circuit is designed as a filling and feed pump of a two-cylinder slurry pump driven by a reversing pump. It is a guided over the reversing pump closed hydraulic circuit, which forms the consumer in the terminology of the present invention together with the reversing pump. In this case, for example, one of the return lines is designed as a drain line of the reversible pump. If, to increase the cooling capacity, the reversing pump leakage oil must be routed through an oil cooler, it may be necessary to provide a check valve in the respective return line in order to protect the reversing pump against pressure peaks from the other recirculation. In addition, a check valve must then be provided, which is connected on the outlet side directly to the suction-return filter or leads directly into the tank.

A further advantageous embodiment of the invention provides that one of the return lines is designed as a flushing oil line connected on the output side to an alternating flush valve of the reversing pump, which is preferably returned to the suction / return filter via the oil cooler.

In principle, it is also possible that one of the hydraulic primary pumps is connected to the drive hydraulics of a distribution mast as a consumer whose return line is connected on the input side to the suction-return filter.

Advantageously, one of the primary pumps or secondary pumps is connected to a hydraulic agitator drive whose return line is connected on the input side to the suction-return filter. Furthermore, one of the secondary pumps in the secondary circuit can be connected to the drive hydraulics of a diverter valve or a slide valve of the slurry pump, whose return line opens into the tank. Furthermore, it is also possible for a separate hydraulic secondary pump to be provided in the secondary circuit. see, which is connected with its pressure side input side to the suction-return filter and supplies at least a portion of the required excess oil. To ensure that the suction / return filter is protected from excessive pressure differences, it is advantageous if a check valve or by-pass valve is arranged between the inlet side of the suction / return filter and the tank. In the following the invention will be explained in more detail with reference to the embodiments schematically illustrated in the drawing. Show it

1 and 2 hydraulic circuit arrangements of hydraulic systems for driving and operating a two-cylinder high-solids pump with suction-return filter.

The hydraulic circuits shown in FIGS. 1 and 2 are intended for a thick matter pump, the two delivery cylinder 10,10 ', the frontal openings 12,12' open into a material feed container, not shown, and alternately during the pressure stroke via a crossover 14 with a conveyor line, not shown, are connectable. The delivery cylinders 10, 10 'are driven in push-pull fashion via hydraulic drive cylinders 16, 16' and the hydraulic reversing pumps 18, 20 designed as swash plate axial piston pumps in the embodiment shown. For this purpose, the delivery pistons 22, 22 'are connected to the drive pistons 24, 24' of the drive cylinders 16, 16 'via a respective common piston rod 26, 26'. Between the delivery cylinders 10,10 'and the drive cylinders 16,16' is a water tank 28 through which the piston rods 26,26 'reach through.

The drive cylinder 16,16 'are in the embodiments shown on the bottom side via hydraulic lines 30, 30', 32, 32 'of a closed Main circuit using the reversing 18.20 charged with hydraulic oil and are hydraulically connected to each other at their rod-side ends via a swing oil pipe 34. The direction of movement of the drive piston 24,24 'and thus the delivery piston 22,22' is reversed, that the swash plates 18 ', 20' of the Reversierpumpen 18,20 triggered by a Umsteuersignal swing through its zero position and thus the conveying direction of the hydraulic oil in the hydraulic lines 30, 30 ', 32, 32' of the main circuit change. In the terminology of the present invention form the drive cylinder 16,16 'together with the reversing 18,20 a consumer AH (drive hydraulics) of the primary circuit of the two-cylinder slurry pump. The trained as feed and filling pumps primary pumps 36,38 load the consumer circuit AH on the check valves 36 ', 36 ", 38', 38" on. The primary pumps 36,38 are arranged in a suction-return system having an output side 40 "connected to a suction-return filter 40 first suction line 42 and its coming from the reversing 18.20 Leckölleitungen as return lines 44,44 'input side 40' to the A further return line 46 is branched off from the drive hydraulic system AH via an alternating purge valve 48 and a low-pressure limiting valve 50 and returned via the oil cooler 52 and the line 54 to the inlet side 40 'of the suction / return filter 40 The suction / return filter system requires an excess quantity of oil in order, for example, to compensate for leakage oil quantities flowing to the tank 68 via the lines 55 or to compensate for short-term missing oil quantities due to the compressibility of the hydraulic oil on the pressure side is at least partially about one in a Se arranged secondarily arranged, motor-driven and at least one second suction line 58 acted upon by hydraulic oil hydraulic secondary pump 60,62. The second suction line 58 communicates Either directly or via a suction filter 66 with the tank 68. On the output side, the secondary circuit is connected to at least one return line, which either opens into the tank 68 or is connected to the input side 40 'of the suction-return filter 40.

The remaining amount of excess oil in the suction-return filter circuit is fed via a biasing valve 70 to the tank 68. The suction-return filter system also includes a check valve on the input side 40 'of the suction-return filter 40, which protects as a bypass valve 72, the filter element of the suction-return filter 40 from excessive pressure difference.

Above all, the advantages of the suction / return filter system consist in the fact that the excess amount of oil in conjunction with the preload valve 70 results in optimum suction conditions for the primary pumps in the primary circuit. Furthermore, the cold start behavior of the primary pumps is improved and the amount of oil circulating through the tank 68 is reduced. The latter means that the tank volume, for example, reduced to less than half the usual size and thus the tank and oil weight and to be exchanged at an oil change amount of oil.

In the embodiment shown in FIGS. 1 and 2, the circuit for actuating and controlling the distribution boom MH is a consumer of the primary circuit. The supply of the mast control via the further primary pump 71, the suction side is connected via the line 73 to the first Sauglei- 42 at the output 40 "of the suction-return filter 40 and the return line 74 via the oil cooler 52 and the line 54 to the input side of In the load part MH of the mast control, the outrigger control can optionally also be integrated, which ensures that the mobile concrete pump with its hydraulically actuated support legs is supported on the ground Differential cylinders, as used, for example, to extend the support legs and to extend them. ren of the mast are used, come to a significant undersupply in the suction-return filter system. This is partially compensated in the embodiment shown by a large amount of excess oil, which is recycled in the secondary circuit with a large secondary pump 60,62 which is connected to the tank 68 to the suction-return filter 40.

In the embodiment shown in FIG. 1, the secondary pump 60 is used for this purpose, which serves as a consumer for controlling an arranged in the material feed tank agitator RS whose return line 76 via the oil cooler 52 and the output line 54 to the input 40 'of the suction-return filter 40 is returned. The embodiment of FIG. 2 differs in this respect from Fig. 1 in that the agitator control RS is supplied with a primary pump 61 via the suction-return filter 40 and the first suction line 42 with hydraulic oil and thus is part of the primary circuit. On the other hand, in the embodiment of FIG. 2, a secondary pump 62 dedicated to the provision of the surplus oil is provided, the suction side 62 'communicates with the tank 68 via the second suction line 58 and the suction filter 66 and the pressure side 62 "either via the oil cooler 52 and the line 54 or via the check valve 78 and the line 80 to the input side 40 'of the suction-return filter 40 is guided.

To the suction filter 66 and the hydraulic pump 64 may be connected to the hydraulic accumulator 82 of the tube switch circuit RW. However, the return 84 of the diverter switch RW must be performed separately to the tank 68, because here 40 impermissible pressure peaks occur for the suction-return filter.

Another special feature of the invention is that at least part of the excess oil quantity is made available via a separate, adequately dimensioned suction line 86. This Nachsaugeleitung 86 is attached to the suction filter 66 in the embodiment shown. closed, from which the primary pumps 36,38,61, 70 of the primary circuit suck in hydraulic oil via a Nachsaugeventil 88 and the first suction line 42. The Nachsaugeleitung 86 must be at least so dimensioned that at maximum Nachsaugemenge the flow rate in the Nachsaugeleitung does not rise above 0.8 m / s and the negative pressure does not fall below the permissible minimum value of the priming primary pump, for example, 0.8 bar. Incidentally, the Nachsaugeleitung 86 and the Nachsaugeventil 88 must be sufficiently large, because there may be an operating condition in which only the primary pump 71 of the mast hydraulic MH is in operation and the drive for the other hydraulic pumps is turned off. In this case, then the secondary pump 60 and 62 for the excess oil amount out of service. Depending on whether the differential cylinders in the mast hydraulics MH or in the support hydraulics retract or off, there is either an excess of oil at the suction return filter 40, which is led to the tank 68 via the preload valve 70, or the result is a Lack of oil, which must then be compensated via the Nachsaugeleitung 86 and the Nachsaugeventil 88 and the suction filter 66 from the tank 68. The embodiment according to FIG. 1 additionally contains the special feature that the leakage oil of the reversing pumps 18, 20 is at least partially conducted via the oil cooler 52, in order to obtain an increase in the cooling capacity. In this case, it has proven to be expedient that a check valve 90 is provided in the leak oil line 44, 44 'in order to protect the reversing pumps 18, 20 of the consumer AH from pressure peaks from the other recirculations. In addition, then a check valve 92 must be provided, which is the output side connected directly to the input 40 'of the suction-return filter 40 or leads directly into the tank 68. In summary, the following should be noted: The invention relates to a hydraulic system, preferably for driving and actuating a two-cylinder slurry pump. The hydraulic system includes a tank 68 for receiving hydraulic oil, a primary circuit having at least one hydraulic consumer AH, MH, the at least one acted upon by a first suction line 42 with hydraulic oil primary pump 36,38,61, 70 and the output side is connected to at least one first return line and the one with the output side Having the first suction line 42 communicating and the input side with return oil from the at least one return line acted upon suction-return filter 40. A special feature of the invention is that the first suction line 42 via a separate Nachsaugeleitung 86 and a suction filter 66 communicates with the tank 68, wherein in the Nachsaugeleitung 86 an in the direction of the suction filter 66 biased Nachsaugeventil 88 is arranged.

LIST OF REFERENCE NUMBERS

10,10 'delivery cylinder

 12.12 'openings

 14 pipe switch

 16.16 'drive cylinder

 18.20 reversible pumps

 18 ', 20' swash plates

 22.22 'delivery piston

 24.24 'drive piston

 26,26 'piston rods

 28 water tank

 30,30 ', 32,32' hydraulic pipes (AH)

 34 swing oil pipe (AH)

 36, 38 primary pumps

 40 suction return filter

 40 'entrance

 40 "output side

 42 first suction line

 44.44 'Leakage pipes (return line)

46 purge line (return line)

48 alternating purge valve

 50 low-pressure relief valve

52 oil cooler

 54 return line

 55 drain pipes

 58 second suction line

 60 secondary pump (RS)

 61 primary pump (RS)

 62 separate secondary pump

64 hydraulic pump 66 suction filter

 68 tank

 70 preload valve

 71 primary pump (MH)

 72 bypass valve

 73 suction line (MH)

 74 return line (MH)

 76 agitator control (RS)

 78 check valve

 80 return line (S, MH)

 82 hydraulic accumulators

 84 return line (RW)

 86 Suction line

 88 After-suction valve

 90 check valve

 92 check valve

 AH drive hydraulics (consumers)

MH Mast Hydraulics (Consumers)

RS agitator control (consumer)

RN pipe switch (consumer)

Claims

claims 1 . Hydrauliksystenn, preferably for driving and operating a slurry pump,  with an atmospheric pressure tank (68) for receiving hydraulic oil,  with a primary circuit comprising at least one hydraulic consumer (ΑΗ, ΜΗ),  the at least one motor-driven, via a first suction line (42) acted upon by hydraulic oil primary pump (36, 38, 61, 71),  the output side is connected to at least one first return line  and the one output side with the first suction line (42) communicating and the input side with return oil from the at least one return line acted upon suction Has return filter (40),  with a branched off from the first suction line (42), via a biasing valve (70) into the tank (68) opening branch line,  with a secondary circuit,  the at least one motor-driven, via a second Suction line (58) Hydraulic oil acted upon secondary pump (60,62),  and the output side is connected to at least one second return line,  wherein the second suction line (58) communicates with the tank (68) directly or via a suction filter (66),  and wherein the second return line either opens into the tank (68) or is connected on the input side to the suction-return filter (40), wherein the first suction line (42) communicates with the tank (68) via a separate suction line (86) and a further suction filter (66) and wherein in the Nachsaugeleitung (86) in the direction of another suction filter (66) biased Nachsaugeventil (88) is arranged. Hydraulic system according to claim 1, characterized in that the further suction filter corresponds to the suction filter (66) in the second suction line (58). Hydraulic system according to claim 1 or 2, characterized in that in at least one of the suction-return filter (40) leading return lines, an oil cooler (52) is arranged. 4. Hydraulic system according to one of claims 1 to 3, characterized in that in at least one of the input side to the suction-return filter (40) connected return lines a check valve (78,90,92) is arranged. 5. Hydraulic system according to one of claims 1 to 4, characterized in that at least one of the primary pumps (36,38) is designed as a filling and feed pump via a reversing pump (18,20) driven nen two-cylinder slurry pump. 6. Hydraulic system according to claim 5, characterized in that one of the return lines as a drain line (44,44 ') of the reversing pump (18,20) is formed. 7. Hydraulic system according to claim 5 or 6, characterized in that one of the return lines as the output side to a Wechselspülventil (48) of the primary circuit connected Spülölleitung (46) is formed. 8. Hydraulic system according to one of claims 1 to 7, characterized in that one of the secondary pumps (60) with a hydraulic Stirrer drive (RS) is connected, the return line (76) is connected on the input side to the suction-return filter (40). 9. Hydraulic system according to one of claims 1 to 8, characterized in that one of the primary pumps (71) with the drive hydraulics of a Verteilernnasts (MH) is connected, the return line (74) is connected on the input side to the suction-return filter (40) , 10. Hydraulic system according to one of claims 1 to 9, characterized in that a hydraulic pump (64) is connected to the drive hydraulics of a pipe switch (RW) or a slide valve Dickstoffpunnpe whose return line (80) opens into the tank (68) , 1 1. Hydraulic system according to one of claims 1 to 10, characterized in that one of the secondary pumps (62) with its pressure side is connected on the input side to the suction-return filter (40). 12. Hydraulic system according to one of claims 1 to 1 1, characterized in that between the input side (40 ') of the suction return filter (40) and the tank (68) a check valve or by-pass valve (72) is arranged.