Improvements in rotary claw pumps

Abstract

A Rotary Claw Pump with at least one pair of intermeshing rotors has the same shape within a tolerance of ±3% of the radii from edges to rotational centers. A convex portion of the claws has a nominal uniform rate of radius change with angle of rotation. There may be multiple stages wherein the thickness of each successive rotor pair maintains profile but has a thickness within 20% of the thickness of the first stage rotor pair multiplied by the inverse products of the compression ratios of the preceding stages. A discharge port is at least partially uncovered at any position of rotation from where intermeshing claw rotor tips are closest to where they are most distant. The discharge port is at least partially connected with a region connected with the rotor tips of both claws during rotation. The discharge port limits pressure increase in the region.

1 . A Rotary Claw Pump wherein at least one pair of intermeshing rotors has the same shape within a tolerance of plus or minus 3 percent of the radii from the edges of their shapes to their centers of rotation and wherein on a convex portion of the claws there is a nominal uniform rate of change of radius with angle of rotation. 
     
     
         2 . A Rotary Claw Pump as in  claim 1  where there are multiple stages wherein the thickness of each successive rotor pair does not vary in profile but has a thickness within 20% of the thickness of the first stage rotor pair multiplied by the inverse products of the compression ratios of the preceding stages. 
     
     
         3 . A Rotary Claw Pump wherein a discharge port is at least partially uncovered at any position of rotation from where a pair of intermeshing claw rotor tips are at their closest point of approach to where the said claw tips are at their furthest apart and wherein said discharge port is at least partially connected with a region connected with the rotor tips of both the said claws during said positions of rotation and the discharge port thereby at least limits pressure increase in the said region. 
     
     
         4 . A Rotary Claw Pump as in  claim 3  wherein the fluid being pumped is at least partly compressible and wherein the said discharge port is connected to an inlet region for the said rotors. 
     
     
         5 . A Rotary Claw Pump as in  claim 3  wherein the fluid being pumped is substantially incompressible and wherein the said discharge port is connected to an outlet region for the said rotors. 
     
     
         6 . A Rotary Claw Pump wherein the working fluid is substantially incompressible and wherein at any position of rotation from where a pair of intermeshing claw rotor tips adjacent to the fluid to be discharged are at their point of closest approach to where the said claw tips are at their position of rotation when they are furthest apart said fluid is at least partially discharged. 
     
     
         7 . A Rotary Claw Pump wherein the working fluid has a liquid and a gas phase and/or the working fluid may be a refrigerant and wherein a discharge passage for said fluid is at least partially opened when a pair of intermeshing claw rotors rotate from a rotational position of the tips of said claws where the pressure in said fluid is within plus or minus 15% of a designated output pressure and wherein said discharge passage remains at least partially opened until the said claw tips are at their furthest apart. 
     
     
         8 . A Rotary Claw Pump wherein over pressurizing is minimized by the provision of one or more valves to relieve one or more internal regions of said pump. 
     
     
         9 . A Rotary Claw Pump wherein the nearest rotor to the driving motor shaft has no intervening bearing between it and the shaft of the driving motor. 
     
     
         10 . A Rotary Claw Pump as in  claim 10  wherein one of the first pair of rotors adjacent to the driving motor is used to couple the motor shaft to the pump. 
     
     
         11 . A Rotary Claw Pump wherein the gears coupling the driving shafts are further way from the output shaft of the driving motor than the furthest pair of rotors from the output shaft of the driving motor. 
     
     
         12 . A multi-stage Rotary Claw Pump wherein the phasing of successive stages is arranged so that each stage is taking in fluid during at least 80% of the time when the immediately preceding stage is discharging fluid. 
     
     
         13 . A Rotary Claw Pump wherein various stages of the pump are arranged to separately compress/discharge and/or provide suction. 
     
     
         14 . A Compressor wherein at least part of the intake gas is cleaned by scrubbing with water, followed by demisting, followed by chilling, followed by demisting and optionally followed by electrostatic precipitation. 
     
     
         15 . A Compressor as in  claim 14  wherein the gas is air. 
     
     
         16 . A Compressor as in  claim 14  wherein the compressor is of the Rotary Claw type. 
     
     
         17 . A Compressor as in  claim 14  wherein the gas is used as the input to a pressure swing separator. 
     
     
         18 . A multi-stage Rotary Claw Pump system to retrievably store electric power as a compressed gas wherein at least two stages of compression have counterflow intercooling heat exchange means arranged to cool the compressed gas after compression and heat the decompressed gas after expansion and wherein, during compression, the heat exchange fluid used in at least some of the said counterflow heat exchangers is drawn from a first fluid store, is passed through said heat exchange means, and is sent to a second fluid store. 
     
     
         19 . A system as in  claim 18  wherein during expansion the heat exchange fluid used in at least some of the said counterflow heat exchangers is drawn from a fluid store which may be said second fluid store, is passed through said heat exchange means, and is sent to another fluid store which may be said first fluid store. 
     
     
         20 . A system as in  claim 18  wherein the temperature of fluid in said first fluid store approaches the lower of ground water and ambient temperatures, but is above the freezing point of the heat exchange fluid and/or wherein the temperature of fluid in said second fluid store is at or above ambient temperature. 
     
     
         21 . A system as in  claim 18  wherein the compression ratios of stages are at least partially optimized to reduce the loss of energy during compression. 
     
     
         22 . A system as in  claim 14  wherein compressed fluid or fluid to be compressed is optionally cooled and condensate is precipitated and optionally removed.