Central inlet conical screw rotor pump - has annular throttle gaps for radially inward leakage flow to central low pressure chamber

摘要

The rotary pump has a housing (30) with central inlet (31) facing a conical screw rotor (33) with limited freedom of axial movement, and a spiral-shaped outlet duct (32). Concentric cylindrical faces of housing and rotor form a first annular throttle opening (43) and opposed radial faces on housing and rotor form a second annular throttle (46) radially inward relative to the first. Between these throttle openings (43,46) there is an annular chamber (at 40) through which leak flow passes from the duct to a low-pressure region (48) near the centre. The rotor may contain ducts (49) through which the liquid in the region (48) is moved to the high-pressure side (32) by centrifugal force.