Vane compressor having suction port and discharge port located at the same axial side thereof

A vane compressor comprising:

• a casing having a wall having an inner peripheral surface and an inner end face, and a suction port and a discharge port formed in said wall, both said suction port and discharge port being located at the same axial side of said casing corresponding to said inner end face;
• a pump housing accomodated within said casing, said pump housing having an outer peripheral surface, at least one pump inlet and at least one pump outlet, said pump housing including an end wall having an outer peripheral surface thereof disposed in contact with said inner peripheral surface of said casing along a whole circumference thereof, said end wall of said pump hosing being in axially spaced and facing relation to said inner end face of said casing and cooperating therewith to define a space therebetween, said outer peripheral surface of said pump housing being radially spaced from said inner peripheral surface of said casing, said end wall of said pump housing having an inner end face;
• said outer peripheral surface of said pump housing, said inner peripheral surface of said casing, and said inner end face of said end wall of said pump housing cooperating to define a first discharge pressure chamber in the form of an annulus therebetween, said at least one pump inlet of said pump housing being formed through said end wall of said pump housing, and said at least one pump outlet of said pump housing opening in said outer peripheral surface of said pump housing;
• a partition member arranged within said casing, said partition member having an outer peripheral surface thereof disposed in contact with said inner peripheral surface of said casing and dividing said space into (i) a suction chamber defined between said end wall of said pump housing and said partition member, and (ii) a second discharge pressure chamber defined between said inner end face of said casing and said partition member, said suction chamber being located axially intermediately between said first and second discharge pressure chambers, and said at least one pump inlet of said pump housing opening into said suction chamber;
• and
• communication passage means communicating said first discharge pressure chamber with said second discharge pressure chamber;
• said suction port of said casing opening in said inner peripheral surface of said casing and communicating with said suction chamber in a substantially direct manner.