Gas pressure regulator with under and over shut-off

A gas pressure regulator comprising:

• a housing having an inlet, an outlet, a transverse wall therebetween, and a chamber communicating with the outlet;
• a diaphragm closing the chamber;
• means yieldably loading the side of the diaphragm remote from the outlet;
• an orifice member connected in the transverse wall having a first valve seat on the inlet side, a second valve seat on the outlet side, and a passage therethrough communicating with said first and second valve seats;
• a regulator valve member cooperating with the second valve seat of the orifice member;
• a shut-off valve member within the orifice member cooperating with the first valve seat, said shut-off valve member including a stem section extending through said passage of said orifice member to contact said regulator valve member under normal operating conditions of said regulator so that the shut-off valve member is prevented from contacting said first valve seat under such normal operating conditions;
• means for yieldably biasing said shut-off valve member into closing contact with said first valve seat;
• a plunger connected to said regulator valve member, said plunger extending into said chamber and supported for reciprocatory axial movement to move said regulator valve member toward and away from said second valve seat;
• a link having a first end pivotally connected to the end of said plunger remote from said regulator valve member;
• a plate mounted for pivotal motion about a first pivot point within said chamber, said plate being pivotally connected at a second pivot point to the second end of said link;
• a stem member coupled for movement with said diaphragm and extending into said chamber;
• a lever coupled to said stem member, said lever being mounted on said plate for pivotal motion about a third pivot point;
• and
• a coiled tension spring connected between a first anchor point on said lever and a second anchor point on said plate;
• said first and second anchor points being so situated that a straight line drawn therebetween lies on a first side of said third pivot point under normal operating conditions of said regulator so that said lever and said plate pivotally move as one about said first pivot point over a range of chamber gas pressures to cause opening movement of the regulator valve member away from said second valve seat upon decrease of chamber gas pressure and closing movement of the regulator valve member toward said second valve seat upon increase of chamber gas pressure, and when the chamber gas pressure exceeds a predetermined upper limit the regulator valve member contacts said second valve seat so that said plate can no longer pivot about said first pivot point and the lever pivots relative to the plate about said third point to extend said spring and move the line between the first and second anchor points to the other side of the third pivot point to "break" the connection between the lever and the plate, said spring then contracting and thereby causing the plate to pivot about the first pivot point in a direction as to pull the link and plunger to move the regulator valve member away from said second valve seat a sufficient distance to allow said shut-off valve member to contact said first valve seat and thereby close said orifice member passage, and when the chamber gas pressure drops below a predetermined lower limit the lever and plate pivot as one about the first pivot point in said direction to such an extent that the regulator valve member is moved away from said second valve seat a sufficient distance to allow said shut-off valve member to contact said first valve seat and thereby close said orifice member passage.