VANES, ROTORS & PUMP PARTS
Vane pumps use GRAPHITAR vanes, liners and rotors. For best performance, GRAPHITAR vanes are machined for a close tolerance fit between vane and rotor, a radiused contact edge and an exact length. Vanes should be specified up to the minimum length of the rotor. No allowance need be made for swelling of the vane in service. GRAPHITAR’s high degree of stability in any pumped medium will maintain the close clearance originally built into the assembly. Centrifugal force is sufficient in most applications to maintain vane contact with the liner. Some slow speed pumps may require the use of a spring, hydraulic or pneumatic pressure behind the vane.
Inlet and outlet ports are usually moulded into GRAPHITAR end plates to avoid radial machining on the pump liner. A commercial lap will give the bearing surface adequate flatness as it will seat itself against the rotating parts in operation. Liners are finished to the same length as the rotor by lapping both ends to a high degree of flatness and parallelism.