Combined pressure regulator and shut-off valve

A regulator valve for regulating fluid pressure and selectively stopping fluid flow, comprising:

• a housing defining a hollow enclosure, an inlet end and an outlet end;
• a seal member disposed in the housing;
• a first plunger disposed in the housing and having a passage therethrough, the first plunger and seal member being movable relative to one another;
• a second plunger disposed in the housing and having a passage therethrough, the first plunger being located between the second plunger and the seal member, the second plunger being movable into and out of engagement with the first plunger, the second plunger engaging the interior of the housing in sealing relation such that fluid flowing from the inlet end to the outlet end must flow through said passages, with said passages being closed to fluid flow when the first plunger engages the seal member;
• one of the second plunger and seal member having a wetted surface exposed to fluid pressure in the housing to bias said one of the second plunger and seal member in one of the directions toward or away from the other;
• a spring in the housing biasing the first plunger in the other of the directions toward or away from the seal member;
• secondary biasing means for selectively moving the first plunger into sealing engagement with the seal member to close the passage.

A regulator valve for regulating fluid pressure and selectively stopping fluid flow, comprising:

• a housing defining a hollow enclosure, an inlet end and an outlet end;
• a seal member disposed in the housing;
• first and second plungers in the housing, each plunger including a tubular stem having a passage therethrough, the passages being in fluid communication with one another, the plungers being movable relative to one another and relative to the seal member, the first plunger being adjacent the seal member and engageable with the seal member;
• first and second diaphragms each having an inner edge connected in sealing engagement to the first and second plungers, respectively, and an outer edge connected in sealing engagement to the interior wall of the housing such that fluid flowing from the inlet end to the outlet end must flow through said passages at a rate which is dependent on the separation between the seal member and the first plunger, with said passages being closed to fluid flow when the first plunger engages the seal member;
• the first and second diaphragms together with the first and second plungers and the housing defining an expansion chamber suitable for receiving pilot pressure fluid therein;
• an inlet port in fluid communication with the expansion chamber;
• a first wetted surface on the first plunger exposed to fluid pressure in the expansion chamber to bias the first plunger toward the seal member;
• a second wetted surface on the second plunger exposed to fluid pressure at the outlet end of the housing to bias the second and first plungers toward the seal member;
• and
• a spring in the housing biasing the first plunger away from the seal member.