AU2006281714A1

AU2006281714A1 - Non-positive compressor

Info

Publication number: AU2006281714A1
Application number: AU2006281714A
Authority: AU
Inventors: Robert Adler; Georg Siebert
Original assignee: Linde GmbH
Current assignee: Linde GmbH
Priority date: 2005-08-12
Filing date: 2006-07-25
Publication date: 2007-02-22
Also published as: CN101243258A; WO2007019947A1; KR20080033397A; DE502006009012D1; EP1913264B1; ATE500424T1; EP1913264A1; DE102005038268A1; CA2618549A1

Abstract

The invention relates to a compressor (1) with at least one displacement cylinder (S), in which an operating fluid (15), in particular, an ionic fluid is arranged which may be brought into connection with a suction inlet (10) and a pumped outlet (11) for medium. The operating medium (15) has a working connection to a drive pump which is an axial piston pump (17). According to the invention, a compressor may be provided with low assembly complexity and a long service life, wherein the suction inlet (10) of the compressor (1) is provided with a pre-compressor (30)

Description

ox 259, Mynoton. Vic 3444 AUSTRALIA e www.ocodemyXL.com e Info@acodomyXL.com e a business of Tonco Sarvices Pcy Ltd e ASN 72 892 315 097 Free 9 1800637640 ntr T +61 3 54 232558 Fox A 03 54 232677 Inter A +61 3 54 232677 TRANSLATION VERIFICATION CERTIFICATE This is to certify that the attached document is an English translation of the -- German-language Patent Application PCT/EP2006/007330 and Academy Translations declare that the translation thereof is to the best of their knowledge and ability true and correct. Academy Translations PO Box 259, Kyneton VIC 3444 AUSTRAUR January 23, 2008 Date Stamp/Signature: AT Ref.: ddc-2066 Multilingual Technical Documentation Translation from German of PCT Application PCT/EP2006/007330 Description 5 Non-Positive Compressor The invention relates to a compressor with at least one displacement cylinder, in which an operating fluid, especially 10 an ionic fluid, is arranged which may be brought into connection with a suction inlet and a delivery outlet for a medium. The operating medium has a working connection to a drive pump which is an axial piston pump. 15 Compressors of this type are used to compress gaseous media. The medium is forced into the displacement cylinder by means of the operating fluid, so that compressors of this type are known as non-positive compressors. An ionic fluid can be used as the operating fluid. It is also possible, however, to use 20 fluids with a low vapour pressure or fluids with low gas solubility. Fluids of this type have the common property that they do not dissolve in the medium, and can be separated from the medium with no residue, so that the compressed medium has a high level of purity. 25 The operating fluid is transported into the displacement cylinders by means of the drive pump, which is designed as an axial piston pump, and is drawn out of the displacement cylinders in order to transport the medium from the suction 30 connection into the outlet connection, and to place it under pressure. When an axial piston pump is used as the drive pump, it is necessary, in order to maintain reliable operation of the compressor, that during the suction stroke of the axial piston pump, in which the operating fluid is drawn out of the 35 displacement cylinder, the pistons in the axial piston 2 machine, which generally have hydrostatic relief, are held on a guide track of the axial piston pump. Provision of a mechanical retraction device on the axial 5 piston pump, which device holds the pistons on the guide track, is known in this regard. A mechanical retraction device, however, has a high level of assembly complexity. A generic non-positive compressor has a long service life, due 10 to the absence of mechanical seals and pistons in the displacement cylinders. Adaptation of an axial piston pump with a mechanical retraction device to the long service life of the non-positive compressor also requires a high level of assembly complexity. 15 The object of the present invention is to provide a compressor of the type indicated above that has a long service life and low assembly complexity. 20 The object is achieved in that the suction inlet of the compressor is provided with a pre-compressor. With a pre compressor upstream of the compressor, a minimum primary pressure of the medium to be transported can easily be generated at the suction inlet of the compressor. This primary 25 pressure generated by the pre-compressor is applied to the operating fluid that is in direct contact with the medium to be transported, as well as to the axial piston pump, and acts on the piston of the axial piston pump during the suction stroke in the direction of the guide track. With a pre 30 compressor according to the invention, it can thus be ensured, with low assembly complexity, that the pistons can be held to the guide track without a mechanical retraction device, or with no changes to the retraction device. It is hereby possible to adapt the service life of the axial piston pump in 35 a simple manner to the long service life of the non-positive compressor, whereby a long service life of the compressor is 3 achieved with low assembly complexity, and with the use of a standardised axial piston pump. Various types of compressors or pumps can be used as a pre 5 compressor. Special advantages are obtained if the pre compressor is designed, in accordance with a preferred embodiment of the invention, as a rotary screw compressor. Due to the long service life of a non-positive compressor, it is necessary to select a pre-compressor with a similarly long 10 service life, in order to prevent the pre-compressor from being the weakest link in the service life chain. A rotary screw compressor does not require operating seals with great leak tightness, so that a standardised rotary screw compressor has a long service life. In addition, a rotary screw 15 compressor generates little pulsation, which allows low noise emissions and low loading of the compressor on the suction side. It is a special advantage that, according to an advantageous 20 further development of the invention, the pre-compressor can be lubricated by means of the operating fluid. Lubricating the pre-compressor with the operating fluid avoids contamination of the medium to be transported by the use of the pre compressor. The rotary screw compressor, due to lubrication by 25 the operating fluid, emits only the operating fluid that is already present in the process, whereby the function of compressor is not negatively affected. According to a preferred further development of the invention, 30 a separation device for separating out the operating fluid from the transported medium is attached to the pumped outlet of the compressor. With a separation device of this type, by means of which the operating fluid that was emitted into the transported medium can be separated from the medium, the 35 operating fluid that was emitted into the transported medium by the pre-compressor, which is lubricated with the operating 4 fluid, can also be separated out. No further separation device is thus required on the suction side of the compressor to separate out any operating fluid emitted into the medium to be transported by the rotary screw compressor that is lubricated 5 with the operating fluid. According to a preferred embodiment of the invention, the axial piston pump features a cylinder barrel in which at least one cylinder space is formed that is connected to the 10 displacement cylinder, whereby a piston is arranged in the cylinder space, such that it can be moved longitudinally, and that is supported on a guide track, especially an adjustable angled washer. A connection can hereby be made in a simple manner between the displacement cylinder and the cylinder 15 space, and thus the piston, in order to achieve secure contact during the suction stage of the drive pump between the piston and the guide track, which is formed by the angled disc, with the primary pressure generated by the pre-compressor. 20 Special advantages are obtained when the displacement cylinders are arranged in a cylinder block and are arranged radially. The radial arrangement of the displacement cylinders in a rotating cylinder block results in centripetal force being applied to the operating fluid in the displacement 25 cylinders, which allows a high rotational velocity of the compressor. A high delivery capacity can thus be achieved with low space requirements for the compressor. In addition, only a small amount of operating fluid is needed, which means that the compressor has low manufacturing and operating costs. 30 According to a preferred constructive embodiment of the invention, the cylinder block and the cylinder barrel are rotationally synchronously coupled, or are made as one piece. 35 To the extent that a pressure of 5-15 bar, especially a pressure of 8-10 bar, can be generated at the suction inlet by 5 the pre-compressor, secure contact of the piston on the guide track formed by the angled washer during operation of the compressor can be ensured with the use of a standardised axial piston pump as the drive pump for the operating fluid. 5 The compressor can be designed for the transport of fluids. Special advantages are achieved if the compressor is designed for the compression of a gaseous medium, especially of 10 hydrogen. With a non-positive compressor according to the invention, in which a primary pressure can be generated at the suction inlet by means of a standardised pre-compressor that is lubricated by the operating fluid, a standardised axial piston pump can be used as the drive pump for the operating 15 fluid, which results in low manufacturing complexity with a long service life of the non-positive compressor, using standardised components. Additional advantages and details of the invention are shown 20 in more detail on the application example shown in the schematic illustration. The illustration shows a compressor 1 according to the invention in a longitudinal cross section. Inside the housing 25 2, a drive shaft 3 is rotatably mounted on a rotary axis 4. A cylinder barrel 5 is synchronously coupled to the drive shaft 3, in which several displacement cylinders 6 are formed. The displacement cylinders 6 here are formed as radial bores 14 arranged in the cylinder barrel 5, and arranged in a star 30 shape around the rotary axis 4, whereby the longitudinal axis 7 of the displacement cylinder 6 is orthogonal to the rotary axis 4 of the drive shaft 3, and thus to the cylinder barrel 5. The displacement cylinders 6 are connected in the inner radial 35 area to one connection channel 8 each, which has a working connection to a disc-shaped control reflector 9, whereby the 6 connection between the displacement cylinders 6 and a suction inlet 10 and a pumped outlet 11 can be controlled during the rotation of the cylinder barrel 5 by means of the control reflector 9. The cylinder barrel 5 is hereby supported in the 5 axial direction by the control reflector 9, which is arranged on a housing cover 12 attached to the housing 2. Operating fluid 15, especially ionic fluid, is arranged in the displacement cylinders 6. 10 Each displacement cylinder 6 is in connection, via a connection channel 13, with a cylinder space 16 of a hydraulic drive pump that is designed as an axial piston pump 17 of the angled disc type. The drive pump that is designed as an axial 15 piston pump 17 hereby features a cylinder block 18 that is arranged coaxially with the cylinder barrel 5, and which is rotationally fixed to the cylinder barrel 5 and the drive shaft 3. It is also possible to design the cylinder block 18 and the cylinder barrel 5 as a common, and thus one-piece, 20 cylinder barrel. The cylinder spaces 16 of the axial piston pump 17 are formed in concentrically arrange longitudinal bores 20 in the cylinder block 18, in each of which a piston 21 is arranged 25 such that it can slide longitudinally. The pistons 21 are each supported by a slide shoe 22 on a guide track 23, which is formed on an angled disc. A ball joint is formed between the piston 21 and the slide shoe 22. 30 The axial piston machine 17 is formed as an axial piston machine that is adjustable in the displacement volume, whereby the angled disc provided with the guide track 23 is pivotally mounted on the housing 2, and can be tilted relative to the axis of rotation 4 by means of an adjusting device that is no 35 longer shown. It is, however, also possible to form the axial 7 piston machine with a fixed displacement volume, whereby the angled disc can be formed directly on the housing 2. The cylinder barrel 5 and the drive pump 17 are hereby 5 arranged in the common housing. According to the invention, the suction inlet 10 of the compressor 1 is aligned with a pre-compressor 30. The pre compressor 30 is designed as a rotary screw compressor, and is 10 lubricated by the operating fluid 15. The pre-compressor 30 hereby generates a primary pressure in the medium of about 8-10 bar at the suction inlet 10. The primary pressure of the medium acts via the operating fluid 15 15 located in the displacement cylinders 6, the connection channels 13 and the cylinder bores 16, which fluid is in direct contact with the medium, on the pistons 21 in the direction of the guide track 23 formed on the angled disc. During the suction stroke of the axial piston pump 17, secure 20 contact between the piston 21 and the guide track 23 is hereby ensured. A separation device 31 is arranged at the pumped outlet 11, with which any operating fluid 15 that may have been emitted 25 in the pumped outlet can be separated from the transported medium. This achieves high purity of the transported medium. During operation of the compressor 1 according to the invention, the cylinder barrel 5 and the cylinder block 18 are 30 driven by the drive shaft 3. The axial piston pump transports operating fluid 15 from the cylinder spaces 16 into the displacement cylinders 6, whereby the medium flowing in to the displacement cylinders 6 via the suction inlet 10 is compressed by the fluid 15 and is transported to the pumped 35 outlet 11. The primary pressure in the medium generated by the pre-compressor 30 at the suction inlet 10 ensures secure 8 contact between the piston 21 of the drive pump, which is designed as an axial piston pump 17, and the guide track 23. During operation of the compressor 1, due to the radial arrangement of the displacement cylinders 6, the rotation of 5 the cylinder barrel 5 generates centripetal force on the fluid 15, which accelerates the operating fluid, whereby the fluid column of the operating fluid 15 in the displacement cylinders 6 can be moved at a high speed, and thus the compressor 1 can be operated at a high rotational speed, and thus a high cycle 10 rate. This results in a high delivery capacity with low space requirements for the compressor 1 and low requirement for operating fluid 15. Due to the primary pressure of the medium generated by the pre-compressor 30, a standardised axial piston pump 17 can be used hereby, which is adapted to the 15 long service life of the non-positive compressor 1 without significant modifications to the mechanical retraction device. The embodiment of the pre-compressor 30 as a standardised rotary screw compressor that is lubricated by the operating fluid 15, allows the service life of a standardised pre 20 compressor 30 to be adapted to the long service life of the non-positive compressor 1 with low assembly complexity. Operating fluid 15 that is emitted from the pre-compressor 30 into the medium to be transported can be separated out of the medium to be transported in a simple manner, using the 25 separation device 31 arranged at the pumped outlet 11. Altogether, a non-positive compressor 1 is thus achievable with low manufacturing complexity, low assembly complexity, and low operating costs.

Claims

1. Compressor with at least one displacement cylinder, in which an operating fluid, especially an ionic fluid, is 5 arranged which may be brought into connection with a suction inlet and a pumped outlet for medium, whereby the operating fluid has a working connection to a drive pump which is an axial piston pump, characterised in that the suction inlet (10) of the compressor (1) is provided with 10 a pre-compressor (30).

2. Compressor as in claim 1, characterised in that the pre compressor (30) is designed as a rotary screw compressor. 15

3. Compressor as in claim 1 or 2, characterised in that the pre-compressor (30) can be lubricated by the operating fluid (15).

4. Compressor as in one of the claims 1 through 3, 20 characterised in that the pumped outlet (11) of the compressor (1) is provided with a separation device (31) for separating out operating fluid (15) located in the medium to be transported. 25

5. Compressor as in one of the claims 1 through 4, characterised in that the axial piston pump (17) features a cylinder barrel (18) in which at least one cylinder space (16) is formed that is connected to the displacement cylinder (6), whereby a piston (21) is 30 longitudinally movably arranged in the cylinder space (16), which piston is supported by a guide track (23), especially an adjustable angled disc.

6. Compressor as in one of the claims 1 through 5, 35 characterised in that the displacement cylinders (6) are 10 arranged in a cylinder block (5) and are arranged radially.

7. Compressor as in one of the claims 5 or 6, characterised 5 in that the cylinder block (5) and the cylinder barrel (17) are rotationally synchronously coupled, or are formed as a single piece.

8. Compressor as in one of the claims 1 through 7, 10 characterised in that a pressure of 5-15 bar, especially a pressure of 8-10 bar, can be generated at the suction inlet by means of the pre-compressor (30).

9. Compressor as in one of the preceding claims, 15 characterised in that the compressor (1) is designed to compress a gaseous medium, especially hydrogen.