Vane compressor

Claim 1

A vane compressor, comprising a hollow stator; a rotor received in said stator for rotation about an axis, said rotor being provided with a plurality of throughgoing passages extending radially and outwardly relative to said axis; a plurality of vanes, each received in one of said passages and having an outer end face directed towards an inner circumference of said stator and an inner end face directed away from said inner circumference of said stator, said vanes being shiftable radially in the respective passages relative to said axis; means for supplying pressure medium under a first pressure to said inner end faces of said vanes to thereby urge said vanes radially outwardly relative to said axis for engagement of said outer end faces with said inner circumference of said stator, said pressure medium supplying means including an annular chamber communicating with said inner end faces of said vanes; means forming a low-pressure chamber; means forming a high-pressure chamber operatively connected with said annular chamber so that pressure in said annular chamber is equal to that in said high-pressure chamber; means for rotating said rotor about said axis whereby said vanes are subjected to an additional second pressure resulting from centrifugal force, which second pressure additionally urges said vanes against the inner circumference of said stator, said first and second pressures together constituting a cumulative pressure which above a predetermined pressure level causes undesired frictional losses at the interfaces between said outer end faces of said vanes and the inner circumference of said stator; and means for decreasing said cumulative pressure at least slightly below said predetermined level to thereby eliminate said undesired frictional losses, said pressure decreasing means include means for connecting said annular chamber with said low-pressure chamber, said connecting means constituting a valve member movable in response to said cumulative pressure between a first position in which said annular chamber is disconnected from said low-pressure chamber and a second postion in which said annular chamber is connected with said low-pressure chamber for permitting the pressure medium flow from said annular chamber into said low-pressure chamber to thereby decrease said cumulative pressure urging said vanes into engagement with said inner circumference of said stator.