Study on the tooth profile for the screw claw-type pump

In this paper, a profile of claw-type rotor is designed by means of the theory of gearing and the equation of undercutting. The designed profiles are suitable for straight rotor lobes if using in a machine with radial suction and discharge ports. Besides, for the twin-screw rotors with claw-shape, we develop a methodology to verify the drawbacks of gas sealing in the design of US patent 6,129,535, US patent 6,139,297 and UK patent 2,292,589. Our numerical results indicate that these patents are unlikely to produce efficient gas sealing between twin-screw rotors. Thus, we propose two modified designs to improve gas sealing and reduce carryover.