EP2461033B1 - Multi-stage piston compressor - Google Patents

Description

The invention relates to a multi-stage piston compressor for a gaseous or cryogenic liquefied medium having at least two compressor stages, which are operatively connected to the common drive with a common drive train, each compressor stage having a piston mechanically connected to the drive train, which is arranged longitudinally displaceable in a compressor cylinder.

A generic multistage piston compressor is known for example from the German patent application 10 2006 042 122 and the European patent application 0744 546 known. Furthermore, from the French patent 320677 a reciprocating compressor is known in which a mechanically driven piston communicates with a liquid column of an incompressible liquid arranged in the compressor cylinder, which converts the piston stroke movement of the piston into a movement of a compressor piston displaceably arranged in the compressor cylinder. Such compressors are used for compressing gaseous or liquid medium, for example hydrogen, nitrogen or natural gas in gaseous or liquid state.

In generic multi-stage compressors in which the pistons of the individual compressor stages are in communication with a common drive train and thus the pistons of the individual compressor stages are mechanically connected to the drive train, the pistons of the compressor stages are driven together by the drive train and lead with actuated drive train one piston movement with a constant piston stroke. Each piston of the corresponding compressor stage is acted upon by the pending in the corresponding compressor stage pressure of the medium. If a compressor stage runs along without compressor power, for example, in a partial load range or no load condition, created by the upcoming pressure of the medium at the follower and the piston stroke piston performing an additional energy needs to be applied via the drive train to drive the piston. In addition, the revolving piston loaded by the impending pressure the drive train, which is particularly unevenly loaded in part-load operation or in no-load operation of a compressor stage of the drive train. Furthermore, occur on the part-load operation or no-load moving piston of a compressor stage Strains and mechanical wear on associated components, such as the sealing means for sealing the piston in the compressor cylinder, the bearings of the piston and the suction valve and the pressure valve of the medium to be compressed. In addition, occurs by the piston stroke of the follower piston of a compressor stage wear on the corresponding surfaces between the piston and the compressor cylinder.

If in a generic multi-stage compressor, the compressor stages are connected in series as a stage compressor and a compressor stage output connected to the input of a next compressor stage, resulting in a generic compressor in which the pistons of the compressor stages are mechanically coupled to a common drive train and driven synchronously be that the input pressure range and the compression ratio of the respective compressor stage are fixed by the fixed and constant piston stroke of the piston of the corresponding compressor stage to a narrow range.

The present invention has for its object to provide a generic multi-stage compressor available in which the compressor stages are independently operable and which is improved in terms of wear and energy efficiency.

This object is achieved in that the piston of the respective compressor stage is in communication with an arranged in the compressor cylinder liquid column of an incompressible liquid, which converts the piston stroke of the piston in a movement of a longitudinally displaceably arranged in the compressor cylinder compressor piston, wherein the liquid column to change the Compressor strokes of the compressor piston can be brought into connection with a drain. According to the invention, therefore, the piston of each compressor stage, which is mechanically coupled to the drive train, communicates via a liquid column of an incompressible liquid, for example a hydraulic fluid, with a compressor piston which carries out the corresponding compressor stroke for compressing the medium to be compressed. Through the connection of the liquid column with a drain, the liquid column of each compressor stage can be changed and varied in accordance with the invention, so that given a constant piston stroke of the piston mechanically driven by the drive train

Compressor stroke of the piston associated compressor piston can be controlled independently of the piston stroke. This makes it possible to turn off a compressor piston partially or completely despite the driven piston and thus immobilize the compressor piston motionless or to control the compressor stroke. In the multistage piston compressor according to the invention, independent and individually operable compressor stages can thus be achieved in a common drive train. As a result of the connection according to the invention of the liquid column of the hydraulic fluid driven by the piston, a partial load operation of a corresponding compressor stage is thus made possible in a simple manner. In addition, the connection of the liquid column with a sequence allows the shutdown of one or more compressor stages, in which the corresponding compressor piston are stopped motionless and perform no movement in the compressor cylinders. Shutting down or changing the compressor stroke of the corresponding compressor piston leads to improved energy efficiency, since no drive power for the stopped piston must be applied or in a part load range by changing the corresponding compressor stroke of the compressor piston, the drive train is evenly loaded. In addition, the mechanical wear on the surfaces between the piston and compressor cylinder, the seals of the piston, the inlet and outlet valve of the medium of a no-load compressor stage by stopping the compressor piston is reduced or avoided.

According to a preferred embodiment of the invention, a valve device is provided for connecting the liquid column with the drain. With a corresponding valve device, the connection of the liquid column driven by the piston drivingly connected to the drive train can be controlled with the sequence so that the valve device conveys the liquid column driven by the piston to the outlet in order to partially or completely shut off the compressor cylinder associated with the piston ,

With particular advantage, according to an embodiment of the invention, the compressor cylinders are connected by means of a respective branch branch line to a collection drain line, the valve device being arranged in the drain branch line. On a multi-stage reciprocating compressor can with a collecting drain line and a corresponding with a valve device provided at each compressor stage in a simple manner the connection of the liquid column of the hydraulic fluid of each compressor stage are individually controlled with the sequence to partially or completely shut off the corresponding compressor piston of the compressor stage.

The valve device is expediently designed as a control valve, in particular slide valve or ball valve, with a blocking position and a flow position. With such a control valve can be easily connected by appropriate operation in the direction of the flow position, the liquid column with the drain to achieve that the piston driven by the drive train promotes the liquid column to drain to control the movement and the compressor stroke of the compressor piston ,

Particular advantages arise when the valve device can be actuated with an electronic control device. With an electronic control device can be controlled by appropriate actuation of the valve devices in a simple manner, the behavior of the compressor.

The collecting drain line is expediently connected to a container, in particular a container under a biasing pressure. With a container under a bias pressure is achieved that the liquid column is conveyed with open valve device under a certain back pressure from the driven piston to the container. A certain biasing pressure in the header drain line may alternatively be achieved by an overflow valve in the header drain line.

Particular advantages arise when, according to a development of the invention, at least one additional valve device is arranged in the collecting drain line or the drain branch line. With additional valve devices, the behavior of the compressor can be influenced and / or controlled in a simple manner.

The additional valve device may be formed according to an embodiment of the invention as a relief valve, in particular pressure relief valve. With a pressure relief valve in the corresponding branch line branch is made possible in a simple manner, the inlet pressure and / or the outlet pressure of the secure corresponding compressor stage, so that the corresponding compressor stage can adapt to a changed input pressure and / or output pressure.

The additional valve device may be formed according to a further embodiment of the invention as a pressure control valve and / or as a flow control valve. With such an additional valve device, a partial load shutdown of the corresponding compressor stage can be made possible in a simple manner.

The drive train according to an advantageous embodiment of the invention comprises a driven by a drive motor crank or eccentric shaft, wherein the pistons are connected by means of a connecting rod to the crankshaft. The piston compressor can in this case be designed as a linear compressor, in which the pistons execute a pure linear movement in the compressor cylinder and the connecting rod is arranged by means of a bearing on the crankshaft. Alternatively, the compressor according to the invention can be formed in a rotary piston construction, in which the pistons perform a pendulum motion in the compressor cylinder and the connecting rod can be rigidly secured to a crank or eccentric shaft.

According to a preferred development of the invention, the liquid column can be brought into contact with a supply source. With a supply source, the liquid column of the corresponding compressor stage can be replenished in a simple manner, in order to enable a connection of the compressor stage. With a supply source can continue to be easily a replacement of the hydraulic fluid and a venting of the liquid column allows.

The supply source expediently comprises a supply pump connected to the container, which feeds into a supply line, wherein the compressor cylinders are in each case connected to a supply line by means of the supply branch line, a respective valve device being arranged in the supply branch line. With a valve device in corresponding supply branch lines, the refilling of the liquid column of the associated compressor stage can be made possible in a simple manner via the supply pump leading into the supply line.

According to a possible embodiment of the invention, the compressor stages are connected in series in a piston compressor according to the invention. With a stage compressor in which at least two compressor stages are connected in series, wherein a compressor stage is connected on the output side to the input of a further compressor stage, a partial load operation of a compressor stage can be made possible in a simple manner by connecting one or all compressor stages according to the invention. As a result, a uniform load of the drive train is achieved. In addition, it is possible that the corresponding compressor stage can adapt to different input and output pressures, whereby the piston compressor according to the invention can be operated in a wide range of input and output pressures.

According to another possible embodiment of the invention, the compressor stages are connected in parallel. In such a reciprocating compressor, in which each compressor stage forms a separate compressor and provides a corresponding delivery rate of the compressed medium, a variable and adjustable delivery rate can be provided in a simple manner by means of the inventive partial or complete deactivation of the individual compressor stages. With the connection according to the invention of the corresponding liquid column of the associated compressor stage, a multiple compressor solution for variable delivery with a common drive train can be realized in a simple manner. The partially or completely shut off compressor stages each form separate independent compressors. If a higher delivery rate is required in such a multi-stage reciprocating compressor, the compressor stages can be connected one after the other. In addition, the compressor according to the invention allows to optimally utilize the installed engine power of the drive motor. If the output side back pressure of the compressed medium is low, several compressor stages can be operated simultaneously. At higher output side back pressure or at a booster operation, the individual compressor stages can be easily switched off to allow adaptation to the engine performance.

Due to the connection according to the invention of the liquid column of the corresponding compressor stage with the outlet, furthermore, in a multi-stage compressor according to the invention, it is possible to select selected compressor stages individually can be operated. As a result, an operation of selected compressor stages is made possible without the other compressor stages having to be able to run, for example in the event of a malfunction of a compressor stage. In the case of a multistage compressor according to the invention, in the case of an accident or a failure of one or more compressor stages, the compressor stages concerned can be switched off and the compressor can continue to be operated with the functional compressor stages.

The piston compressor according to the invention may be designed such that the compressor pistons operated by means of the liquid column are in direct contact with the medium to be compressed and compact the medium. According to a preferred development of the invention, the compressor is designed as an ionic compressor, the compressor piston of the corresponding compressor stage being in contact with a liquid column of an ionic operating fluid arranged in the compressor cylinder, which serves to compress the medium. Such ionic compressors, in which the medium to be compressed is displaced from the ionic liquid column in the displacement cylinder, are preferably used for the compression of gaseous media, for example hydrogen.

In a multi-stage reciprocating compressor according to the invention, it is made possible by the connection of the liquid column with the outlet that a compressor stage or several compressor stages can be partially or completely shut off when the drive train continues to run. The partial shutdown of individual compressor stages allows a simple way a partial load operation of selected compressor stages. The complete shutdown of individual compressor stages allows the adjustment of the compressor power to the installed engine power of the drive motor of the drive train and / or the achievement of a variable compressor power. In addition, the complete shutdown of individual compressor stages, a continued operation of the compressor in a disturbed or inoperable compressor stage is made possible.

In addition, in a multistage piston compressor according to the invention it is made possible that an emergency shutdown of the compressor with further running of the drive train can be achieved by the connection of the liquid columns of all compressor stages with the sequence. In a multi-stage piston compressor according to the invention can be achieved by the simultaneous connection of all liquid columns of the compressor stages with the Expiration emergency dump be realized, in which all compressor stages are switched off without the drive train would have to be brought to a stop immediately.

Figur 1

eine schematische Darstellung eines erfindungsgemäßen mehrstufigen Kolbenverdichters und

Figur 2

eine Weiterbildung der Erfindung.

Further advantages and details of the invention will be explained in more detail with reference to the embodiments illustrated in the schematic figures. This shows

FIG. 1

a schematic representation of a multi-stage piston compressor according to the invention and

FIG. 2

a development of the invention.

In the FIG. 1 an inventive multi-stage piston compressor 1 is shown, which in the present embodiment comprises four compressor stages A, B, C, D.

Each compressor stage A, B, C, D comprises a piston 3A, 3B, 3C, 3D arranged longitudinally displaceably in a compressor cylinder 2A, 2B, 2C, 2D. For the common drive of the pistons 3A-3D, the pistons 3A-3D are in operative connection with a common drive train 4.

In the exemplary embodiment shown, the drive train 4 consists of a crankshaft or eccentric shaft 6 driven by a drive motor 5, for example an electric motor or internal combustion engine, wherein the pistons 3A-3D are mechanically connected to the crankshaft 6 by means of a connecting rod 7A-7D. In the articulation of the connecting rod 7A-7D on the crank or eccentric shaft 6, a bearing 8A-8D can be formed.

According to the invention, each piston 3A-3D is connected by means of a liquid column 9A-9D made of an incompressible medium, for example a hydraulic fluid, in the compressor cylinder 2A-2D to a compressor piston 2A-2D longitudinally displaceable compressor piston 10A-10D, which is connected directly or with the interposition of a Liquid column of an ionic operating fluid 30A-30D for compressing the medium to be compressed M is used, for example, gaseous or liquid hydrogen. For sealing the piston 3A-3D against the corresponding compressor cylinder 2A-2D schematically illustrated sealing means are provided.

The kinematics of the crankshaft 6 and the connecting rod 7A-7D leads in a driven drive train 4 to a predetermined, constant piston stroke KH between an upper bottom dead center of the corresponding piston 2A-2D of the respective compressor stages A-D.

According to the invention, furthermore, the respective liquid column 9A-9D of the associated compressor stage A-D can be connected to a drain 15.

For this purpose, a collection drain line 21 led to a container 20 is provided, to which the respective compressor cylinders 2A-2D are connected by means of a respective respective branch line 22A-22D. To control the connection of the liquid column 9A-9D with the collection drain line 21 and thus for the corresponding discharge of hydraulic fluid of the associated liquid column 9A-9D, a valve device 23A-23D is arranged in each drain branch line 22A-22D. The container 20 may be under a slight bias.

The valve device 23A-23D can be designed as a slide valve or ball valve which can be actuated between a flow position and a blocking position.

For replenishing hydraulic fluid from the container 20 into the corresponding liquid column 9A-9D of the compressor stages AD, a supply source 25 is provided, which has a supply pump 26 which is connected to the container 20 on the suction side and conveys the conveyor side into a supply line 27. The compressor cylinders 2A-2D are connected to the supply line 27 by means of a respective supply branch line 28A-28D. In the supply lines 28A-28D, a respective valve device 29A-29D is arranged for the corresponding filling of hydraulic fluid of the associated liquid column 9A-9D. The valve device 29A-29D can be designed as a slide valve or ball valve which can be actuated between a flow position and a blocking position.

By appropriate actuation of the valve device 23A-23D hydraulic fluid can be discharged from the corresponding liquid column 9A-9D, so that at a predetermined and constant piston stroke KH of the associated piston 3A-3D according to in the FIG. 1 above, the pressure medium flow of the hydraulic fluid of the liquid column 9A-9D conveyed in the compressor cylinder 2A-2D is partially or completely conveyed to the outlet 15 and thus into the container 20 when the valve device 23A-23D is open. When the valve device 23A-23D is open, it is thus prevented that the hydraulic fluid delivered by the mechanically driven piston 3A-3D can not or only partly reach the associated compressor piston 10A-10D and cause a corresponding movement of the compressor piston 10A-10D. As a result of this diversion of the delivered hydraulic fluid of the liquid column 9A-9D into the collection drain line 21, the affected compressor stage AD and thus the compressor piston 10A-10D can be switched partially or completely without load and thus motionless. The drive train 4 can continue to run and drive the other compressor stages.

The connection according to the invention of the liquid column 9A-9D of the respective compressor stage AD with the outlet 15 thus makes it possible to vary and change the compressor stroke VH of each compressor piston 10A-10D independently of the constant piston stroke KH of the associated piston 3A-3D, while still allowing is to completely stop the compressor piston 10A-10D with compressor stroke VH zero. The control of the liquid column 9A-9D with the drain 15 and thus the container 20 thus makes it possible to partially or completely shut off a compressor cylinder 10A-10B. Individual control of the valve device 23A-23D furthermore allows the compressor stroke VH of each compressor piston 10A-10D to be controlled and changed independently of the compressor stroke of the other compressor pistons of the further compressor stages.

In the FIG. 2 is a development of the invention with reference to a compressor stage A of the compressor 1 according to the invention illustrated. The further compressor stages BD of the compressor 1 according to the invention can be designed accordingly.

According to the FIG. 2 the compressor 1 is formed as an ionic compressor 1, wherein the compressor piston 10 A formed as a phase separator, which is moved by the hydraulic fluid and thus the liquid column 9A-9D, with an in The liquid column of an ionic operating fluid 30A located in the compressor cylinder 2A is in contact, which carries out a compressor stroke corresponding to the compressor stroke VH of the compressor piston 10A at the fill level mirror 31. The ionic operating fluid 30A serves to compress the medium M, which is located in a displacement chamber formed by the displacement cylinder 2A and the ionic operating fluid 30A. By means of an inlet valve 32A and an outlet valve 33A on the compressor cylinder 2A, the medium M can be sucked and ejected.

In the FIG. 2 Furthermore, an electrical actuating device 40A, for example a magnet or an electric actuator, for actuating the valve device 23A arranged in the branch line 22A is shown. The valve device 23A can be actuated by means of an electronic control device 41, which for this purpose is in communication with the actuating device 40A.

According to the FIG. 2 At least one auxiliary valve device 50A is arranged in the drain branch line 22A. In the present exemplary embodiment, an overflow valve 51A, for example a pressure limiting valve, and a control valve 52A, for example pressure regulating or pressure limiting valve, are arranged in the outflow branch line 22A as additional valve device 50A.

In a multistage compressor 1 according to the invention, there are a number of advantages.

In the multistage piston compressor 1 according to the invention, independent compressor stages AD can be achieved in a common drive train 4 with a single drive motor 5. In the multi-stage reciprocating compressor 1 according to the invention with a common drive train 4, individual compressor stages AD can be partially or completely switched off and thus operated in part-load operation or without load or individual compressor pistons are switched motionless. This results in improved energy efficiency and reduced load on the drive when the compressor stage is switched off. In addition, in a motionless compressor piston of a compressor stage, a reduced load and a reduced mechanical wear is achieved, for example, to the seals of the compressor piston and the surfaces of the compressor piston and the compressor cylinder and the valves of the compressor stage.

The partial or complete decoupling of individual compressor stages from the drive train further results in increased energy efficiency in partial load operation. In addition, this allows the load of the drive train to be kept uniform.

Furthermore, it is achieved by the inventive individual shutdown of the individual compressor stages that the compressor 1 can adapt to changing input and output pressures of the medium to be compressed. In a multistage piston compressor according to the invention designed as a stage compressor, operation in an enlarged input pressure range and a variable compression ratio at the corresponding compressor stages are thus made possible.

By arranging one or more additional valve devices in the outlet branch lines of the corresponding compressor stage, it is possible to influence the behavior of the compressor in a simple manner and / or to control. By arranging an overflow valve, for example a pressure relief valve, and / or a control valve, for example a pressure control valve or a flow control valve, in the corresponding branch line branch of a compressor stage one or more Abschaltungsvarianten (partial load, pressure limiting, complete shutdown) of the corresponding compressor stage can be easily made possible.

Claims (18)

1. Multiple-stage piston compressor (1) for a gaseous or cryogenically liquefied medium (M) having at least two compressor stages (A, B, C, D) which are operatively connected for joint driving with a common drive train (4), each compressor stage (A, B, C, D) having a piston (3A, 3B, 3C, 3D) which is connected mechanically to the drive train (4) and is arranged longitudinally displaceably in a compressor cylinder (2A, 2B, 2C, 2D), characterized in that the piston (3A; 3B; 3C; 3D) of the respective compressor stage (A; B; C; D) is connected to a liquid column (9A; 9B; 9C; 9D) of an incompressible liquid which is arranged in the compressor cylinder (2A; 2B; 2C; 2D) and converts the reciprocal piston movement of the piston (3A; 3B; 3C; 3D) into a movement of a compressor piston (10A; 10B; 10C; 10D) which is arranged longitudinally displaceably in the compressor cylinder (2A; 2B; 2C; 2D), it being possible for the liquid column (9A; 9B; 9C; 9D) to be connected to an outflow (15) in order to change the compressor stroke (VH) of the compressor piston (10A; 10B; 10C; 10D).
2. Multiple-stage piston compressor according to Claim 1, characterized in that a valve device (23A; 23B; 23C; 23D) is provided for connecting the liquid column (9A; 9B; 9C; 9D) to the outflow (15).
3. Multiple-stage piston compressor according to Claim 2, characterized in that the compressor cylinders (2A; 2B; 2C; 2D) are connected by means of in each case one outflow branch line (22A; 22B; 22C; 22D) to a collecting outflow line (21), the valve device (23A; 23B; 23C; 23D) being arranged in the outflow branch line (22A; 22B; 22C; 22D).
4. Multiple-stage piston compressor according to Claim 2 or 3, characterized in that the valve device (23A; 23B; 23C; 24D) is configured as a control valve, in particular a slide valve or ball cock, with a shut position and a throughflow position.
5. Multiple-stage piston compressor according to one of Claims 2 to 4, characterized in that the valve device (23A; 23B; 23C; 23D) can be actuated by way of an electronic control device (41).
6. Multiple-stage piston compressor according to one of Claims 3 to 5, characterized in that the collecting outflow line (21) is connected to a container (20), in particular a container under a preload pressure.
7. Multiple-stage piston compressor according to one of Claims 3 to 6, characterized in that at least one additional valve device (50A) is arranged in the collecting outflow line (21) or in the outflow branch line (22A; 22B; 22C; 22D).
8. Multiple-stage piston compressor according to Claim 7, characterized in that the additional valve device (50A) is configured as an overflow valve (51A), in particular a pressure limiting valve.
9. Multiple-stage piston compressor according to Claim 7 or 8, characterized in that the additional valve device (50A) is configured as a control valve (52A), in particular a pressure control valve.
10. Multiple-stage piston compressor according to one of Claims 7 to 9, characterized in that the additional valve device (50A) is configured as a throughflow limiting valve.
11. Multiple-stage piston compressor according to one of Claims 1 to 10, characterized in that the drive train (4) comprises a crankshaft or eccentric shaft (6) which is driven by a drive motor (5), the pistons (3A; 3B; 3C; 3D) being connected by means of in each case one connecting rod (7A; 7B; 7C; 7D) to the crankshaft or eccentric shaft (6).
12. Multiple-stage piston compressor according to one of Claims 1 to 11, characterized in that the liquid column (9A; 9B; 9C; 9D) can be connected to a supply source (25).
13. Multiple-stage piston compressor according to Claim 12, characterized in that the supply source (25) comprises a supply pump (26) which is connected to the container (20) and delivers into a supply line (27), the compressor cylinders (2A; 2B; 2C; 2D) being connected by means of in each case one supply branch line (28A; 28B; 28C; 28D) to the supply line (27), in each case one valve device (29A; 29B; 29C; 29D) being arranged in the supply branch line (28A; 28B; 28C; 28D).
14. Multiple-stage piston compressor according to one of Claims 1 to 13, characterized in that the compressor stages (A; B; C; D) are connected in series.
15. Multiple-stage piston compressor according to one of Claims 1 to 13, characterized in that the compressor stages (A; B; C; D) are connected in parallel.
16. Multiple-stage piston compressor according to one of Claims 1 to 15, characterized in that the compressor (1) is configured as an ionic compressor, the compressor piston (10A; 10B; 10C; 10D) of the corresponding compressor stage (A; B; C; D) being in contact with a liquid column, arranged in the compressor cylinder (2A; 2B; 2C; 2D), of an ionic operating liquid (30A; 30B; 30C; 30D) which serves to compress the medium (M).
17. Multiple-stage piston compressor according to one of Claims 1 to 16, characterized in that, as a result of the connection of the liquid column (9A; 9B; 9C; 9D) to the outflow (15), a compressor stage (A; B; C; D) or a plurality of compressor stages (A, B, C, D) can be switched off partially or completely while the drive train (4) continues to run.
18. Multiple-stage piston compressor according to one of Claims 1 to 16, characterized in that, as a result of the connection of the liquid columns (9A, 9B, 9C, 9D) of all the compressor stages (A, B, C, D) to the outflow (15), an emergency switch-off of the compressor (1) is made possible while the drive train (4) continues to run.

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