Screw vacuum pump having a decreasing pitch for the screw members
AssigneeKowel Precision Co., Ltd.
InventorKisu Im
Life of this patent
Estimating the term…
Abstract
A screw displacement pump has a chamber. Inlet and outlet are provided for the admission of gas to and discharge of gas from the chamber. Intermeshing screw members rotatably mounted within the chamber for delivering the gas from the inlet to outlet, wherein the pitch of the screw members decrease continuoulsy from the inlet end thereof to the outlet end thereof to cause compression of the gas being delivered. The continuous reduction in the pitch distance from the inlet end to the outlet end is generated by the following relationship: Pitch at the outlet end/Pitch at the inlet end<.pi..sub.i /k where, .pi..sub.i =pressure ratio calculated under the condition that the process is effected in a adiabatic and the work done is constant, C.sub.1 =0, and k is gas constant.
Claims2
A screw vacuum pump comprising a body defining a chamber, at least one inlet at an inlet end and at least one outlet at an outlet end for the admission of fluid to and discharge of fluid from the chamber, and a pair of intermeshing screw members rotatably mounted within the chamber for transporting the fluid from the inlet end to the outlet end, wherein the pitch of the screw members varies from the inlet end thereof to the outlet end thereof according to the following relation:
- Pitch at the outlet end/Pitch at the inlet end<.pi..sub.i /k
- where, .pi..sub.i =k.sup.k/(k-1) =pressure ratio calculated under the conditions that the operation is effected in an adiabatic process and the work done is constant, and k is gas constant, and wherein
- said screw members include a plurality of teeth having a shape of an epitrochoid and archimedean curve, whereby to cause compression of the fluid being delivered.
A screw vacuum pump comprising a body defining a chamber, at least one inlet at an inlet end and at least one outlet at an outlet end for the admission of fluid to and discharge of fluid from the chamber, and a pair of intermeshing screw members rotatably mounted within the chamber for transporting the fluid from the inlet end to the outlet end, wherein the pitch of the screw members decreases from the inlet end thereof to the outlet end thereof according to the following relation;
- Pitch at the outlet end/Pitch at the inlet end<.pi..sub.i /k
- where, .pi..sub.i =k.sup.k/(k-1) =pressure ratio calculated under the conditions that the operation is effected in an adiabatic process and the work done is constant, and k is gas constant, and wherein
- said screw members include a plurality of teeth having a shape of an epitrochoid and archimedean curve, whereby to cause compression of the fluid being delivered.
Dependencies are inferred from the claim text.