Compression method and means

Abstract

The invention is a compression method having characteristics of smooth compression and internal cooling of the gas. Embodiments of the invention employ a cylindrical chamber and an orbiting rotor to create a moving duct or chamber whose walls converge, relative to a static gas packet drawn into the moving duct, at a “pinch point”. Preferably the closing speed of the walls is subsonic and the speed of the pinch point is supersonic. This enables high pressure to co-exist, at the narrowing end of the duct, with low pressure elsewhere in the duct, because of the pressure information barrier produced by the supersonic advance of the pinch point. The invention also discloses means for providing gas inlet and outlet functionality, and means for providing a variable flow compressor.

1 . A compressor or expander having a rotor and a stator forming a closed volume therebetween and arranged for relative traversal, so as to form a pinch point at the point of nearest proximity, wherein at least one of the rotor and the stator has a movable portion such that the closed volume is controllably variable. 
     
     
         2 . An apparatus according to  claim 1  wherein the pinch point is arranged to move at substantially supersonic velocity. 
     
     
         3 . An apparatus according to  claim 1  wherein the rotor has a variable geometry formed by said movable portion. 
     
     
         4 . An apparatus according to  claim 3  wherein said movable portion comprises a rotor surface portion which is movable in a direction having a radial component relative to an axis of rotation of the rotor. 
     
     
         5 . An apparatus according to  claim 4  wherein the movable rotor surface portion is arranged to be actuated by fluid pressure. 
     
     
         6 . An apparatus according to  claim 5  wherein the fluid pressure is hydraulic pressure. 
     
     
         7 . An apparatus according to  claim 5  wherein the fluid pressure is pneumatic pressure. 
     
     
         8 . An apparatus according to  claim 3  comprising a first flange arranged for rotation in the stator and for defining a boundary of the closed volume. 
     
     
         9 . An apparatus according to  claim 8  comprising a second flange arranged for rotation in the stator and for defining another boundary of the closed volume. 
     
     
         10 . An apparatus according to  claim 9  wherein one of the flanges comprises said movable portion, movable in an axial direction of the rotor. 
     
     
         11 . An apparatus according to  claim 10  wherein the movable flange is supported on an axially movable member. 
     
     
         12 . An apparatus according to  claim 10  wherein the movable flange is supported in an axial groove in the rotor. 
     
     
         13 . An apparatus according to  claim 8  wherein the first flange has an inlet opening for allowing fluid to enter the compressor, the inlet opening being arranged such that in use it trails the pinch point in the direction of rotation. 
     
     
         14 . An apparatus according to  claim 13  wherein a portion of the leading edge of the inlet opening extends at least partly away from the rotor in an axial direction so as to form a scoop. 
     
     
         15 . An apparatus according to  claim 8  wherein the second flange has an outlet opening for allowing fluid to leave the compressor, the outlet opening being arranged such that in use it leads the pinch point in the direction of rotation. 
     
     
         16 . An apparatus according to  claim 1  wherein the rotor includes a labyrinth seal in the region of the pinch point. 
     
     
         17 . An apparatus according to  claim 15  comprising a third flange arranged for rotation in the stator and axially spaced from the second flange, so as to define an output diffusion chamber. 
     
     
         18 . An apparatus according to  claim 17  wherein the stator comprises an outlet passage, and the output diffusion chamber and the outlet passage are arranged for radial communication therebetween. 
     
     
         19 . An apparatus according to  claim 17  wherein the output diffusion chamber comprises a ramp adjacent the outlet opening, the ramp oriented such that gas exiting the compressor axially through the outlet opening is redirected contrary to the direction of rotation. 
     
     
         20 . An apparatus according to  claim 9  wherein each flange incorporates one or more labyrinth seals. 
     
     
         21 . An apparatus according to  claim 20  wherein the labyrinth seal comprises circumferential grooves extending from a point adjacent the pinch point to another point adjacent the pinch point and on the other side of the pinch point, such that the grooves are sealed in the region of the pinch point. 
     
     
         22 . An apparatus according to  claim 1  further comprising outlet valving means comprising a resilient deformable disc arranged to seal against an axial end of the stator. 
     
     
         23 . An apparatus according to  claim 1  wherein the rotor is shaped so as to form a plurality of pinch points at respective points of proximity with the stator. 
     
     
         24 . An apparatus according to  claim 23  wherein the rotor is generally elliptical in shape. 
     
     
         25 . An apparatus according to  claim 23  wherein the generally elliptical rotor includes a relatively narrow central portion and lobes either side thereof. 
     
     
         26 . An apparatus according to  claim 1  in which the rotor incorporates a passage arranged to communicate axially with the housing, and with the duct. 
     
     
         27 . An apparatus according to  claim 1  wherein the rotor surface includes a portion adjacent to the pinch point in which proximity of the portion to the stator varies as the rotor is traversed in an axial direction. 
     
     
         28 . An apparatus according to  claim 27  in which the proximity of the portion decreases with distance along the axis from an inlet side. 
     
     
         29 . An apparatus according to  claim 27  in which the proximity of the portion decreases with distance along the axis from an outlet side. 
     
     
         30 - 35 . (canceled) 
     
     
         36 . A turbine or pump comprising a compressor or expander according to  claim 1 . 
     
     
         37 . A method of compressing or expanding a fluid comprising the steps of:
 arranging a rotor and a stator to form a closed volume therebetween, and for relative traversal, so as to form a pinch point at the point of nearest proximity, and   arranging at least one of the rotor and stator to have a movable portion, such that the closed volume is controllably variable.   
     
     
         38 - 39 . (canceled)