An externally-supported rotary fluid machinery and a method for eliminating axial rotor displacement. The fluid machinery includes a box body, an air cylinder and a rotor, wherein the rotor is eccentrically mounted in the air cylinder; the air cylinder is mounted in the box body; one end of a sliding plate is inserted in the rotor, and the other end is embedded in a wall of the air cylinder; a fluid inlet is provided on the box body, and a fluid outlet is provided on the air cylinder; a support end of the rotor protrudes out of the box body and is supported in a rotor bearing support structure; and a support end of the air cylinder also protrudes out of the box body and is supported in an air cylinder bearing support structure.

A rotary vane pump or rotary vane motor including a rotatable rotor being eccentrically arranged within a rotatable cylindrical housing sleeve defining a freely rotary working chamber which takes out the relative sliding movement and friction inside to outer housing bearing. A partition element of a vane hingedly attached to the rotor; wherein the partition element travels with the rotor following the orbit of the housing incident to the expansion and contraction of the working space performing as a true dynamic radial seal; The rotor assembly along with the housing assembly being sandwiched between end-plates to fulfill dynamic side seal; The end-plates may contain pressure and non-pressure ports as well as holes for shaft, bearings, brackets and mounting hardware.

A compressor includes fixed and movable members with a discharge port penetrating the fixed member and a discharge valve body to open and close the discharge port. An inflow end of the discharge port has a hydraulic diameter Di=4(Ai/Li), where Ai is an area of the inflow end and Li is a circumferential length at the inflow end. An outlet flow path is formed between an outflow end of the discharge port and the valve body. The outlet flow path has a cross-sectional area Ao=Loho, and a hydraulic diameter Do=4{Ao/(Lo+Lv)}, where Lo is a circumferential length at the outflow end, ho is a reference lift amount of the valve body, and Lv is a circumferential length of a valve head of the valve body in contact with the outflow end. A ratio Do/Di at the inflow end is 0.602 to 0.740.

A compressor includes fixed and movable members with a discharge port penetrating the fixed member and a discharge valve body to open and close the discharge port. An inflow end of the discharge port has a hydraulic diameter Di=4(Ai/Li), where Ai is an area of the inflow end and Li is a circumferential length at the inflow end. An outlet flow path is formed between an outflow end of the discharge port and the valve body. The outlet flow path has a cross-sectional area Ao=Loho, and a hydraulic diameter Do=4{Ao/(Lo+Lv)}, where Lo is a circumferential length at the outflow end, ho is a reference lift amount of the valve body, and Lv is a circumferential length of a valve head of the valve body in contact with the outflow end. A ratio Do/Di at the inflow end is 0.602 to 0.740.