Patent ID: 7524311

Claim:
An automatic high-negative pressure relief valve a portion of which is in fluid communication with a chamber, said relief valve comprising: a housing having an interior compartment; a biasing mechanism; a sealing member moveably disposed within the housing and being operably coupled to the biasing mechanism; wherein the sealing member includes a flexible member that extends between interior surfaces of the housing dividing the interior compartment into first and second sub-compartments, where the first sub-compartment is fluidly coupled to the chamber and the second sub-compartment is fluidly coupled to the gas source; wherein the biasing member urges the sealing member against a seating surface to close the relief valve when the differential pressure developed across the sealing member is less than a predetermined value; and wherein the sealing member moves away from the seating surface to open the relief valve and to fluidly couple the chamber to the gas source when the differential pressure developed across the sealing member is greater than a predetermined value; and an adjustment mechanism operably coupled to the biasing mechanism, the adjustment mechanism being configured and arranged so as to selectively adjust a force developed by the biasing mechanism corresponding to the predetermined value, the adjustment mechanism being threadedly coupled to the housing, wherein the predetermined value is reduced in response to turning the adjustment mechanism in a first direction and the predetermined value is increased in response to turning the adjustment mechanism in a second direction.