Patent ID: 7387014

Claim:
A vacuum generator for pulling a vacuum in a system to be tested for leaks, said vacuum generator comprising: a source of inlet gas under pressure; a spool valve having an internal passage running therethrough, said spool valve moving through a spool valve bore in response to a pushing force applied to said spool valve; a vacuum generating venturi located between the internal passage of said spool valve and the atmosphere; and a vacuum passage to be connected between the system under test and said vacuum generating venturi so that the system under test can be evacuated to the atmosphere, said spool valve moving from a first position within said spool valve bore at which the internal passage running through said spool valve is isolated from said source of inlet gas and said vacuum passage is disconnected from the system under test to a second position within said spool valve bore at which the internal passage running through said spool valve communicates with said source of inlet gas to complete a gas flow path along which gas under pressure is blown from said source of inlet gas to the atmosphere by way of said vacuum generating venturi, and said vacuum passage is connected to the system under test to complete a vacuum path from the system under test to the atmosphere, whereby a vacuum condition is created in the system under test by means of said vacuum generating venturi, the ability of the system under test to maintain the vacuum condition over time providing an indication if the system under test has a leak.