Abstract:
An exemplary revolving vane compressor includes a cylinder having a discharge port in and through the cylinder. A rotor housed within the cylinder is eccentrically mounted relative to the cylinder. A vane is mounted in a slot in the rotor. The vane is for sliding movement relative to the rotor. The vane is securely connected to the cylinder to force the cylinder to rotate with the rotor. A pressure shell surrounds the cylinder and the rotor. Each discharge port is for discharging fluid into an enclosed volume of the pressure shell. The cylinder is held within the enclosed volume.

Description:
This Application is the National Phase under 35 U.S.C. §371 of PCT International Application No. PCT/SG2007/000187, which has an international filing date of 28 Jun. 2007 and has designated the United States of America. 
    
    
     REFERENCE TO RELATED APPLICATION 
     Reference is made to our provisional patent application filed in the United States on 7 Jul. 2006 under No. 60/819,009 for an invention entitled “Revolving Vane Compressor”, the contents of which are hereby incorporated by reference as if disclosed herein in their entirety, and the priority of which is claimed. 
     TECHNICAL FIELD 
     This invention relates to a revolving vane compressor and refers particularly, though not exclusively, to a revolving vane compressor with a rotor eccentrically mounted relative to a cylinder. 
     BACKGROUND 
     One of the crucial factors affecting the performance of a compressor is its mechanical efficiency. For example, the reciprocating piston-cylinder compressor exhibits good mechanical efficiency, but its reciprocating action results in significant vibration and noise problems. To negate such problems, rotary type compressors have been developed and have since gained much popularity due to their compact nature and good vibration Characteristics. However, as their parts in sliding contact generally possess high relative velocities, frictional losses are predominant and have thus limited the efficiency and reliability of the machines. For instance, in Rotary Sliding Vane compressors, the rotor and vane tips rub against the cylinder interior at high velocities, resulting in enormous frictional losses. Similarly, in Rolling-Piston compressors, the rolling piston rubbing against the eccentric and the cylinder interior also result in significant losses. It is therefore believed that if the relative velocities of the rubbing components in rotary compressors can be effectively reduced, their overall performance and reliability can be improved substantially. 
     SUMMARY 
     According to an exemplary aspect there is provided a revolving vane compressor comprising a cylinder, a rotor housed within the cylinder and being eccentrically mounted relative to the cylinder, and a vane mounted in a slot in the rotor for sliding movement relative to the rotor, the vane being securely connected to the cylinder to force the cylinder to rotate with the rotor. 
     The rotor may be configured to be driven by a drive shaft. The rotor may be configured to drive the cylinder by operative connection of the vane to the cylinder. The rotor may have a rotor longitudinal axis and the cylinder may have a cylinder longitudinal axis parallel to and spaced from the rotor longitudinal axis. The rotor may further comprise a rotor shaft co-axial with rotor longitudinal axis. There may be a suction inlet in the rotor shaft operatively connected to at least one suction port in a surface of the rotor. The operative connection may comprise a first portion of a suction inlet extending axially of the rotor shaft, and a second portion extending radially of the rotor. 
     The cylinder may comprise a side wall and a pair of opposed end plates all of which are configured to rotate with the rotor. The cylinder may further comprise at least one discharge port in and through the cylinder. Each discharge port may comprise a discharge valve. Each discharge valve may comprise a discharge valve reed over each discharge port, and a valve stop. Each discharge port may be in and through the side wall of the cylinder. The revolving vane compressor may further comprise a high-pressure shell. Each discharge port may be for discharging fluid into an enclosed volume of the high-pressure shell. 
     The vane may comprise an enlarged head that engages the cylinder in the manner of a hinge-type joint. The slot may extend relative to the rotor in a manner selected from: radially of the rotor, at an offset angle relative to the rotor, and circularly curved relative to the rotor. 
     A working chamber may be formed between the cylinder and the rotor. The working chamber may comprise a suction chamber and a compression chamber. The vane may separate the working chamber into the suction chamber and the compression chamber. A line contact may be formed between the rotor and an internal surface of the cylinder. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the invention may be fully understood and readily put into practical effect there shall now be described by way of non-limitative example only exemplary embodiments, the description being with reference to the accompanying illustrative drawings. 
       In the drawings: 
         FIG. 1  is a front perspective in partial cutaway of an exemplary embodiment; 
         FIG. 2  is a vertical partial cross-sectional view along the lines and in the direction of arrows  2 - 2  on  FIG. 1 ; 
         FIG. 3  is a vertical cross-sectional view along the lines and in the direction of arrows  3 - 3  on  FIG. 1 ; 
         FIG. 4  is a series of illustrations corresponding to  FIG. 2  showing the working cycle of the exemplary embodiment of  FIGS. 1 to 3 ; 
         FIG. 5  is a front perspective in partial cutaway of the exemplary embodiment; 
         FIG. 6  is an enlarged, vertical cross-sectional view of the discharge valve of the exemplary embodiment of  FIG. 5 ; 
         FIG. 7  is a vertical cross-sectional view corresponding to  FIG. 2  of another exemplary embodiment; and 
         FIG. 8  is a vertical cross-sectional view corresponding to  FIG. 2  of a further exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIGS. 1 to 6 , there is a revolving vane compressor  10  that has similar components to a known rotary sliding vane compressor but with only one vane  12 . The main components are: a rotor  14 , the vane  12  and a cylinder  16 . 
     The vane  12  is assembled with the rotor  14  such that it is a sliding fit within a radially-directed, blind slot  18  in the outer portion of the rotor  14 . Both the vane  12  and the rotor  14  are housed in the cylinder  16 . The enlarged and curved head  20  of the vane  12  is connected via a hinge-type joint  21  to an internal surface  22  of a side wall  24  of the cylinder  16 , the side wall  24  being cylindrical and of a larger diameter than the rotor  14 . This provides a secure attachment of the vane  12  to the cylinder  16 . 
     The rotor  14  is mounted for rotation about a first longitudinal axis  26  and the cylinder  16  is mounted for rotation about a second longitudinal axis  28  ( FIG. 3 ). The two axes  26 ,  28  are parallel and spaced apart such that the rotor  14  and the cylinder  16  are assembled with an eccentricity. In consequence, during rotation of the rotor  14  and the cylinder  16 , a line contact  30  always exists between the rotor  14  and the interior surface  22  of the side wall  24 . Both the rotor  14  and the cylinder  16  are supported individually and concentrically by journal bearing pairs  32 . Both the rotor  14  and the cylinder  16  are able to rotate about their respective longitudinal axes  26 ,  28  respectively, the two axes  26 ,  28  also being the axes of rotation. 
     A drive shaft  34  is operatively connected to or integrated with the rotor  14  and is preferably co-axial with the rotor  14 . The drive shaft  34  is able to be coupled to a prime mover (not shown) to provide the rotational force to the rotor  14  and thus to the cylinder  16  via the vane  12 . 
     During operation, the rotation of the rotor  14  causes the vane  12  to rotate which in turn forces the cylinder  16  to rotate due to the secure attachment provided by the hinge-type point  21 . The motion causes the volumes  36  trapped within the vane  12 , cylinder  16  and the rotor  14  to vary, resulting in suction, compression and discharge of the working fluid. 
     The cylinder  16  also has flanged end plates  38  that may be integral with the side wall  24 , or may be separate components securely attached to side wall  24 . As such, the end plates  38  also rotate as the entire cylinder  16 , including side wall  24  and end plates  38 , is made to rotate by the vane  12 , and thus rotate with the rotor  14 . By doing so friction between the vane  12  and the internal surface  22  of the side wall  24  is virtually eliminated. However, it does cause the addition of a cylinder journal bearing at journal bearing pair  32  to support the rotating cylinder  16  which results in additional frictional losses. Those losses are of a lower magnitude as it is relatively easy to provide lubrication to the journal bearing pairs  32 . Also, frictional loss between the rotor  14  and the cylinder end plates  38  is reduced to a negligible level, as will be explained below. 
     The entire cylinder  16 , with the end plates  38 , is able to rotate. This reduces friction at the sliding contacts between the end faces  38  of the cylinder  16 , and the rotor  14 . This is because the relative, sliding velocity between the end plates  38  and the rotor  14  is significantly reduced. 
     Although known designs using fixed end plates simplify the positioning of the discharge and the suction ports, they result in significant frictional losses. They have a stationary housing against which the rotor rotates, thus inducing large frictional losses. This reduces the mechanical efficiency of the machine, and also reduces reliability due to greater wear-and-tear. The heat generated by the friction also reduces the overall compressor performance due to suction heating effects. 
     As all the primary components of the compressor  10  are in rotation, the suction and discharge ports are also in motion. The compressor  10  therefore may have a high-pressure shell  40  that surrounds the cylinder  16  and rotor  14 . The high-pressure shell  40  is stationary, with the cylinder  16  and rotor  14  rotating within and relative to the shell  40 . 
     The suction inlet  44  is along the rotor shaft  34  and co-axial with the axis of rotation  26  of the rotor  14  and is operatively connected to the suction pipe (not shown). The suction inlet  44  has a first portion  46  that extends axially of the shaft  42 ; and one or more second portions  48  that extend radially of the rotor  14  to the outer surface  50  of the rotor  14  to provide one or more suction ports  52 . The number of second portions  48  and suction ports  52  may depend on the use of the compressor  10 , and the axial extent of the rotor  14 . 
     One or more discharge ports  54  are positioned in and through the side wall  24  of the cylinder  16 . As such the discharged gas or fluid is contained within the hollow interior  56  of the shell  40  before exiting from the compressor  10  using a known exit apparatus. The discharge ports  54  each have a discharge valve assembly  58  positioned over the discharge ports  54 . The discharge valve assembly  58  has a valve stop  60  securely mounted to the side wall  24  of cylinder  16  by a fastener  62 ; as well as a discharge valve reed  64  over the discharge port  54 . 
     The compression cycle is shown in  FIG. 4 . In (a) there is shown the compressor  10  at the beginning of the suction phase to draw the working fluid into the suction chamber  66 ; and the compression of the working fluid in the compression chamber  68 . The vane  12  separates the working chamber  36  into the suction chamber  66  and the compression chamber  68 . When the compressor  10  has reached the position in (b), the suction of the fluid into the suction chamber  66  and compression in the compression chamber  68  is continuing. In (c) the suction process continues, and the discharge of the fluid through discharge ports  54  occurs when the pressure inside the compression chamber  68  exceeds that of the hollow interior  56  of the shell  40 . At (d) the suction and discharge of the fluid have almost completed. As can be seen, the only movement of the vane  12  is a sliding movement relative to its slot  18  during the movement of the rotor  14  relative to cylinder  16 . From an external, fixed frame the line contact  30  appears stationary. But from within the cylinder  16  the line contact  30  appears to move around the internal surface  22  of sidewall  24  once every complete revolution of the cylinder  16  and rotor  14 . 
     The vane  12  of  FIGS. 1 to 6  is orientated radially to the rotational center of the rotor  14 . However, a non-radial vane  212  in a non-radial slot  218  may be used as is shown in  FIG. 7 . The figure shows a vane that has an offset angle to give a trailing-type vane  212 . However, the offset angle may be negative to give a leading-type vane  212 . Similarly, and as shown in  FIG. 8 , a circularly-arced vane  312  may be used that slides in a circularly-arced slot  318 . 
     Whilst there has been described in the foregoing description exemplary embodiments, it will be understood by those skilled in the technology concerned that many variations in details of design, construction and/or operation may be made without departing from the present invention.