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Wobble plate compressorRelated Patent Categories: Pumps, Successive Stages, Reciprocating Rigid Stages, Three Or MoreWobble plate compressor description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070196216, Wobble plate compressor. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] The present invention relates in general to compressors and, for example, to a wobble plate compressor as well as to use of a wobble plate compressor for compressing natural gas. BACKGROUND OF THE INVENTION [0002] Wobble plate machines are essentially piston machines in which the piston(s) is/are not driven by a crank but by a swash or wobble plate, i.e. a plate skew seated on an axis which "wobbles" on rotation of the axis, but not like a radial plate in which the points rotate in the vicinity of the edge, instead in a rotary plane inclined to the axis. Arranged opposite this wobble plate for each piston is a stationary con rod substantial parallel to the drive shaft and the con rod(s) are advanced or retracted by the wobbling plate. [0003] In practice such wobble plate machines are mainly employed as pumps (i.e. for pumping incompressible fluids, in other words liquids). Basic use of the wobble plate design in pumps is known, for example, from the German "Dubbel" mechanical engineering text book, 17.sup.th Edition, published by Springer-Verlag, 1990, pages H4-H8. [0004] In addition, wobble plate machines also find use as compressors (i.e. compressors for compressible fluids, i.e. gases), particularly in refrigerators. Thus wobble plate type refrigerant compressors are known, for example, from U.S. Pat. No. 4,008,005 as well as from EP 0 530 730 A1. In these wobble plate machines the actual wobble plate is non-rotatable but is controlled by a rotatable wobble member to produce the wobble motion. To compensate, at least in part, one disadvantage of non-compensated forces and moments general to wobble plate machines (substantially resulting from gas forces during compression and sudden relaxation when the outlet valve is opened and the mass forces stemming from the reciprocating pistons) it is proposed in the cited documents to arrange a plurality of (in this case, five or six) piston-cylinder assemblies regularly distributed circumferentially. The plurality of cylinders is connected in parallel as regards the delivery of the gas flow to be compressed. It is generally the case that these known wobble plate pumps have a relatively low compression ratio since a refrigerant is compressed generally to not more than 2 bar. [0005] A further wobble plate type refrigerant compressor is known from EP 0 599 642 A1 in which it is proposed to equip the piston-cylinder assemblies with piston rings of polytetrafluoroethylene (PTFE). [0006] Known in conclusion are special types of wobble plate compressors in which the piston-cylinder assemblies extend not just to one side of the wobble plate but to both sides as it reads from U.S. Pat. No. 5,611,675 (with a swash plate), DE patent 530 071 and FR patent 918.307 (with two wobble plates seated on a common shaft, inclined to each other). SUMMARY DESCRIPTION OF THE INVENTION [0007] The invention relates to a wobble plate compressor comprising at least one wobble plate associated with at least two piston-cylinder assemblies. The wobble plate compressor forms a multistage compressor in which the piston-cylinder assemblies are connected in series in the flow and the cubic capacity of the piston-cylinder assemblies is progressively reduced in series. [0008] A further aspect relates to a method in which one such wobble plate compressor is used for compressing natural gas to a pressure of at least 200 bar. [0009] Another aspect relates to a wobble plate compressor comprising at least one pair of wobble plates, each of which is associated with at least one piston-cylinder assembly. Each of the two wobble plates is powered by a drive shaft stub, the two drive shaft stubs being arranged coaxially counter-rotating. [0010] Further features read implicitly from the disclosed devices or are evident to the person skilled in the art from the following detained description of embodiments and the attached drawing. BRIEF DESCRIPTION OF THE DRAWING [0011] Embodiments of the invention will now be described by way of example with reference to the attached drawing in which: [0012] FIG. 1 is a full view of a dual wobble plate compressor shown in partial longitudinal section; [0013] FIG. 2 is a view of half of the dual wobble plate compressor as shown in FIG. 1 but here on a magnified scale; and [0014] FIG. 3 is an illustration showing use of the compressor as shown in FIGS. 1 and 2 for compressing natural gas in fuelling a vehicle with compressed natural gas (CNG). DESCRIPTION OF THE PREFERRED EXAMPLE EMBODIMENTS [0015] FIGS. 1 and 2 show by way of an example a wobble plate compressor. Before detaining FIGS. 1 and 2 the embodiments are firstly explained as follows: [0016] In some of the embodiments as described in the following a wobble plate type compressor is provided suitable for achieving a high overall compression ratio. For this purpose the wobble plate compressor in some embodiments is configured as a multistage compressor in which a plurality of piston-cylinder assemblies is connected in series in the flow and the cubic capacity of the piston-cylinder assemblies is progressively reduced in series. Multistage compressors are known (e.g. as it reads from the German "Dubbel" mechanical engineering text book, 17.sup.th Edition, published by Springer-Verlag, 1990, pages P23-P33); these known multistage compressors are all crankshaft type piston compressors, however. [0017] In some of the embodiments the piston-cylinder assemblies connected in series are interconnected in series by conduit and valve assemblies. [0018] The multistage configuration achieves substantial final pressures: based on atmospheric pressure and ignoring the effects of the gas being heated and cooled and its friction loses, some embodiments are capable of achieving, for example, with a compression ratio of roughly 1:4 per cylinder, an increase in pressure of 16 bar and 256 bar in a two and four cylinder series assembly respectively. However, the true pressures attained are usually less, because of the effects ignored in the above achievements. In some embodiments forced cooling of the cylinders and/or of their interconnecting conduits is needed to achieve an effective intermediate cooling, e.g. by forced ventilation with ambient air or cooling by cooling water, etc. In other embodiments merely convection cooling of the pistons and/or the conduits by ambient air is provided for. [0019] In some embodiments e.g. four piston-cylinder assemblies are assigned per wobble plate, whereas in other embodiments just two piston-cylinder assemblies are provided per wobble plate which, as such, is less favorable as regards force and moment compensation. But in a few of these embodiments--as detained further on below--a second wobble plate is provided in a casing, powered counter-rotatively to the first wobble plate and arranged together therewith in a common casing. The casing can thus absorb the forces and moments of the two wobble plate assemblies in partly compensating them counterwise, since due to the counter rotative arrangement they are employed opposite in sign at least in part. Continue reading about Wobble plate compressor... Full patent description for Wobble plate compressor Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Wobble plate compressor patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Wobble plate compressor or other areas of interest. ### Previous Patent Application: Motor-compressor Next Patent Application: Cylinder head arrangement for a piston compressor Industry Class: Pumps ### FreshPatents.com Support Thank you for viewing the Wobble plate compressor patent info. IP-related news and info Results in 0.33918 seconds Other interesting Feshpatents.com categories: Electronics: Semiconductor , Audio , Illumination , Connectors , Crypto , 174 |
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