Hydrostatic system and pumping station for an oil or gas pipeline

Abstract

A hydrostatic system has a pressure source and a hydraulic motor or a consumer. An additional hydraulic motor/pump unit is furnished for controlling the volumetric flow for the consumer or the power output of the hydraulic motor.

Claims

1. A hydrostatic system, comprising: a hydraulic pressure source; a first hydraulic motor having an output shaft that forms a mechanical power output of the hydrostatic system, and/or at least one consumer that is provided with pressurized hydraulic medium from said hydraulic pressure source; a pressure line connecting one or both of said first hydraulic motor, for its own propulsion, or said at least one consumer, for pressurization, to said hydraulic pressure source; a hydraulic motor/pump unit including an additional hydraulic motor and a hydraulic pump, propulsively connected with each other, to enable said hydraulic pump to be propelled by said additional hydraulic motor; said additional hydraulic motor being connected to said hydraulic pressure source, for its own propulsion, in series with said first hydraulic motor and/or in series with said at least one consumer; and said hydraulic pump having a pressure side connected to said pressure line.

2. The hydrostatic system according to claim 1, further comprising a hydraulic reservoir, being a hydraulic tank or a hydraulic sump, and at least one charge pump for supplying said hydraulic pressure source from said hydraulic reservoir.

3. The hydrostatic system according to claim 2, wherein said hydraulic pressure source comprises at least one pressure accumulator connected to a charge pump pressure side of said charge pump, for supplying hydraulic medium into said pressure accumulator.

4. The hydrostatic system according to claim 3, wherein said additional hydraulic motor is connected to said hydraulic reservoir for feeding hydraulic medium from said pressure line into the hydraulic reservoir.

5. The hydrostatic system according to claim 2, wherein said hydraulic pressure source comprises at least one pressure accumulator and a gas accumulator connected to said pressure accumulator, which is in a flow-conducting connection with a gas side of the pressure accumulator, or configured to be switched into a flow-conducting connection.

6. The hydrostatic system according to claim 5, wherein said hydraulic pressure source comprises a plurality of pressure accumulators.

7. The hydrostatic system according to claim 2, further comprising a suction line connecting a suction side of said hydraulic pump to said hydraulic reservoir.

8. The hydrostatic system according to claim 1, further comprising a variably adjustable throttle valve for controlling a pressure in the pressure line connected in said pressure line on an input side or output side of said first hydraulic motor, said additional hydraulic motor and/or said at least one consumer.

9. The hydrostatic system according to claim 1, wherein the propulsive connection between said additional hydraulic motor and said hydraulic pump is exclusively a mechanical connection.

10. The hydrostatic system according to claim 1, wherein the propulsive connection between said additional hydraulic motor and said hydraulic pump is a rigid coupling.

11. The hydrostatic system according to claim 10, wherein said rigid coupling is a shaft that carries impellers of said additional hydraulic motor and of said hydraulic pump and/or is torsionally rigidly connected to said impellers.

12. The hydrostatic system according to claim 1, wherein said additional hydraulic motor is a displacement motor and/or said hydraulic pump is a variable displacement pump with a variably adjustable delivery volume per revolution.

13. The hydrostatic system according to claim 1, further comprising a transmission gearing having a variable speed ratio connected in the propulsive connection between said additional hydraulic motor and said hydraulic pump.

14. The hydrostatic system according to claim 1, further comprising an electric generator or electric motor-generator connected to said hydraulic motor/pump unit for energy storage, for reversible energy storage and/or for providing electrical energy.

15. The hydrostatic system according to claim 1, wherein said additional hydraulic motor is configured for operation as a hydraulic pump with or without reversal of a flow direction of the hydraulic medium.

16. The hydrostatic system according to claim 1, wherein said hydraulic pump is driven by a motor.

17. A pumping station for an oil or gas pipeline, the pumping station comprising: a hydrostatic system according to claim 1; at least one feed pump for conveying oil or gas through the pipeline; at least one internal combustion engine connected to said hydrostatic system and configured for driving said at least one feed pump; wherein said internal combustion engine is in, or configured to be switched into, a propulsive connection with the first hydraulic motor for starting up said internal combustion engine, or said internal combustion engine is a consumer that is provided with pressurized hydraulic medium from the hydraulic pump.

18. A hydrostatic system, comprising: a hydraulic pressure source; at least one first hydraulic motor and/or consumer acted upon by pressurized hydraulic medium; a hydraulic motor/pump unit including an additional hydraulic motor and a hydraulic pump that are in a propulsive connection with each other, enabling said hydraulic pump to be propelled by said additional hydraulic motor; a pressure line connecting said additional hydraulic motor to said pressure source for its own propulsion; and said first hydraulic motor being connected to a pressure side of said hydraulic pump, for its own propulsion and/or for pressurizing the hydraulic medium for said consumer.

19. The hydrostatic system according to claim 18, further comprising a hydraulic reservoir, being a hydraulic tank or a hydraulic sump, and at least one charge pump for supplying said hydraulic pressure source from said hydraulic reservoir.

20. The hydrostatic system according to claim 19, wherein said hydraulic pressure source comprises at least one pressure accumulator connected to a charge pump pressure side of said charge pump, for supplying hydraulic medium into said pressure accumulator.

21. The hydrostatic system according to claim 20, wherein said hydraulic pressure source comprises a plurality of pressure accumulators.

22. The hydrostatic system according to claim 20, wherein said additional hydraulic motor is connected to said hydraulic reservoir for feeding hydraulic medium from said pressure line into the hydraulic reservoir.

23. The hydrostatic system according to claim 19, wherein said hydraulic pressure source comprises at least one pressure accumulator and a gas accumulator connected to said pressure accumulator, which is in a flow-conducting connection with a gas side of the pressure accumulator, or configured to be switched into a flow-conducting connection.

24. The hydrostatic system according to claim 19, further comprising a suction line connecting a suction side of said hydraulic pump to said hydraulic reservoir.

25. The hydrostatic system according to claim 18, further comprising a variably adjustable throttle valve for controlling a pressure in the pressure line connected in said pressure line on an input side or output side of said first hydraulic motor, said additional hydraulic motor and/or said at least one consumer.

26. The hydrostatic system according to claim 18, wherein the propulsive connection between said additional hydraulic motor and said hydraulic pump is exclusively a mechanical connection.

27. The hydrostatic system according to claim 18, wherein the propulsive connection between said additional hydraulic motor and said hydraulic pump is a rigid coupling.

28. The hydrostatic system according to claim 27, wherein said rigid coupling is a shaft that carries impellers of said additional hydraulic motor and of said hydraulic pump and/or is torsionally rigidly connected to said impellers.

29. The hydrostatic system according to claim 18, wherein said additional hydraulic motor is a displacement motor and/or said hydraulic pump is a variable displacement pump with a variably adjustable delivery volume per revolution.

30. The hydrostatic system according to claim 18, further comprising a transmission gearing having a variable speed ratio connected in the propulsive connection between said additional hydraulic motor and said hydraulic pump.

31. The hydrostatic system according to claim 18, further comprising an electric generator or electric motor-generator connected to said hydraulic motor/pump unit for energy storage, for reversible energy storage and/or for providing electrical energy.

32. The hydrostatic system according to claim 18, wherein said additional hydraulic motor is configured for operation as a hydraulic pump with or without reversal of a flow direction of the hydraulic medium.

33. The hydrostatic system according to claim 18, wherein said hydraulic pump is driven by a motor.

34. A pumping station for an oil or gas pipeline, the pumping station comprising: a hydrostatic system according to claim 18; at least one feed pump for conveying oil or gas through the pipeline; at least one internal combustion engine connected to said hydrostatic system and configured for driving said at least one feed pump; wherein said internal combustion engine is in, or configured to be switched into, a propulsive connection with the first hydraulic motor for starting up said internal combustion engine, or said internal combustion engine is a consumer that is provided with pressurized hydraulic medium from the hydraulic pump.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 a first embodiment of the invention with an internal combustion engine that may be propelled by a first hydraulic motor;

(2) FIG. 2 an alternative configuration of the invention with a consumer that is supplied with pressurized hydraulic medium by means of the hydraulic pump of the motor/pump unit.

DESCRIPTION OF THE INVENTION

(3) FIG. 1 shows a hydrostatic system according to the invention which is used to propel an internal combustion engine, in particular a pumping station for an oil or gas pipeline. However, the invention is not limited to this.

(4) In FIG. 1, the internal combustion engine is numbered as 1, and the feed pumps of the gas pipeline 4, which are shown by way of example, are given numbers 2 and 3. The representation of the pumping station 5 is highly schematic.

(5) The hydrostatic system for starting the internal combustion engine 1 has a hydraulic motor 10, which may be coupled to the internal combustion engine 1 via a clutch 6. In addition or instead of the clutch 6, one or more gear ratios and/or at least one transmission may also be furnished.

(6) The hydraulic motor 10 is supplied from a hydraulic pressure source 11. In the exemplary embodiment shown, the pressure source 11 comprises a pressure accumulator 12, here in the form of an accumulator with a gas tightener. Preferably, an additional gas-filled, and in particular nitrogen-filled, gas accumulator 13 is connected to the pressure accumulator 12, and is connected to the gas side of the pressure accumulator 12 or may be switched into such a flow-conducting connection. Thus, the gas spring of the pressure accumulator may be enlarged and the maximum possible hydraulic medium reservoir in the pressure accumulator 12 increases while the pressure remains constant, in particular at a constant pretension pressure of the gas spring and a constant maximum storage pressure. The gas accumulator 13 has, for example, the same volume as the pressure accumulator 12.

(7) In FIG. 1, it is indicated schematically that in addition to the first hydraulic motor 10, at least one consumer 14 could be furnished in the hydraulic system, which is supplied with hydraulic medium from the pressure source 11. Such a consumer 14 may be, for example, a working cylinder, a hydraulic motor, a pump or the like. The invention is also applicable to a hydrostatic system in which only a corresponding consumer 14 is furnished, and there is no first hydraulic motor 10.

(8) The pressure source 11 may be filled with hydraulic medium by means of a charge pump 15. The charge pump 15 is propelled, for example, by an electric motor 16 and delivers hydraulic medium from the hydraulic reservoir 17.

(9) To control the first hydraulic motor 10, in particular to start the internal combustion engine 1 while minimizing the energy consumed from the hydraulic pressure source 11, a hydraulic motor/pump unit 18 is provided that has an additional hydraulic motor 19 and a hydraulic pump 20, the hydraulic pump 20 being propelled by the additional hydraulic motor 19.

(10) As is indicated schematically, the additional hydraulic motor 19 may be designed as a fixed displacement motor or as a variable displacement motor. Correspondingly, the hydraulic pump 20 may be designed as either a fixed displacement pump or a variable displacement pump. The hydraulic pump 20 may be connected to the additional hydraulic motor 19 in a fixed speed ratio and in particular solely mechanically, so that it rotates in particular at the same rotational speed. Alternatively, a transmission gearing 21 having a variable speed ratio may be provided in the propulsive connection between the additional hydraulic motor 19 and the hydraulic pump 20.

(11) The additional hydraulic motor 19 is connected to the hydraulic pressure source 11, in series with the first hydraulic motor 10 and/or the at least one consumer 14.

(12) By operation of the motor/pump unit 18, the pressure provided by the hydraulic pressure source 11 is reduced, so that the first hydraulic motor 10 provides a correspondingly lower propulsive power at its output shaft 25, which constitutes the power output of the hydrostatic system. At the same time, as a result of propelling the hydraulic pump 20, the volumetric flow through the first hydraulic motor 10 is increased, so that fine-grained control may be achieved, and only the desired small quantity of energy may be drawn off from the hydrostatic system.

(13) As needed, the hydraulic motor/pump unit 18 may include an electric generator or motor-generator 22 to take off additional energy from the hydraulic circuit by charging the electrical accumulator 23. When a motor-generator 22 is provided, this energy may later be fed back into the system by propelling the hydraulic pump 20 and/or the additional hydraulic motor 19.

(14) If the additional hydraulic motor 19 may be operated as a pump that supplies the hydraulic reservoir 17, the differential pressure across the first hydraulic motor 10 or the at least one consumer 14 is increased. In this case, it is also possible that the additional hydraulic motor 19 provides increased pressure for another subsystem or another consumer. In order to thus propel the additional hydraulic motor 19, the motor-generator 22 and/or the hydraulic pump 20 may be used, if the same may be operated by a motor.

(15) If the control capacity of the motor/pump unit 18 is not sufficient to ensure the desired reduction in the propulsive power of the first hydraulic motor 10, and thereby to minimize the consumption of hydraulic medium from the pressure source 11, an adjustable throttle valve 24 may additionally be provided in the pressure line 26 that connects the pressure source 11 to the consumer 14 and/or the first hydraulic motor 10, so as to selectively throttle the hydraulic medium flow from the pressure source 11 to a greater or lesser extent. As a general matter, such a throttle valve 24 could also be provided downstream of the consumer 14 and/or first hydraulic motor 10, in the flow direction of the hydraulic medium, in order to increase the pressure downstream and thereby to reduce the pressure difference across the consumer 14 and/or first hydraulic motor 10.

(16) In FIG. 2, an alternative configuration of the invention is shown, in which the same reference numerals are used for corresponding parts. In the configuration of FIG. 2, the pressure accumulator 12 is likewise filled by means of the charge pump 15, but in this case this occurs via a check valve 31. This is not mandatory, however.

(17) Also in the configuration of FIG. 2, a hydraulic motor/pump unit 18 is furnished, wherein the additional hydraulic motor 19 is connected to the pressure line 26 and thus connected to the pressure source 11 for its own propulsion. In contrast, for supplying hydraulic medium or pressure to the consumer 14, the hydraulic pump 20 of the hydraulic motor/pump unit 18 is used. Likewise, the hydraulic pump 20 supplies hydraulic medium from the hydraulic medium reservoir 17 to the consumer 14. In this way, the consumer 14 is not connected to the pressure line 26 in series with the additional hydraulic motor 19; instead, the pressure source 11 serves only indirectly to supply pressurized hydraulic medium to the consumer 14. As indicated by the dashed lines in FIG. 2, a first hydraulic motor 10 could be provided in turn, and supplied with hydraulic medium from the hydraulic pump 20, either instead of the consumer 14 or in addition to the consumer 14. The switching on and off of the first hydraulic motor 10 may take place, for example, via a valve 30 shown here in particular, by way of example, as a switching valve or directional control valve.

(18) For example, a sensor 33 is furnished which, together with a control device 34, determines the rotational speed of the hydraulic motor/pump unit 18 and thus indirectly determines the current hydraulic medium consumption of the consumer 14 or the rotational speed of the first hydraulic motor 10 and/or a unit propelled by that motor. A corresponding sensor may of course also be used in the configuration according to FIG. 1.

(19) In the configuration according to FIG. 2, an internal combustion engine, for example a pumping station for an oil or gas pipeline, could also be propelled or accelerated by means of the first hydraulic motor 10, likewise analogously to the embodiment of FIG. 1 or a similar design.