Vapor jet vacuum pump and method of manufacture

摘要

A vapor jet vacuum pump includes a pump housing, a boiler sealed to the pump housing and a jet assembly mounted within the pump housing. The pump housing is a low porosity metal casting and has an inlet and a foreline. The boiler includes a boiler housing defining a reservoir for a liquid, and a heater for vaporizing the liquid to form a vapor. The jet assembly directs a vapor jet toward the housing. In a preferred embodiment, the boiler housing is a low porosity metal casting. A method for making the pump housing includes the steps of casting two or more low porosity housing blanks, machining the housing blanks to provide finished housing elements and attaching the finished housing elements together to form the pump housing. <IMAGE>