摘要 |
A reduced noise screw expander is described, which comprises a main rotor and a gate rotor each having an ‘N’ profile. The rotors are designed so that the torque on the gate rotor caused by pressure forces is in the same direction as the torque on the gate rotor caused by frictional drag forces. A method of designing a screw machine exhibiting reduced noise is also described. The screw machine has two or more rotors having an ‘N’ profile, and the method involves determining a ratio r/r1, where r is the main rotor addendum and r1 is the radius of the rack round side, and ensuring that this ratio is greater than 1.1 where the screw machine is to be a screw compressor or less than or equal to 1.1 where the screw machine is to be a screw expander. |