Preloaded piezo actuator and gas valve employing the actuator

A valve arrangement for controlling gas flow, comprising:

• a gas block having a gas inlet, a gas outlet, and a gas cavity fluidly connecting the gas inlet to the gas outlet;
• a diaphragm configured for controlling gas flow between the gas inlet and the gas outlet;
• an actuator configured to vary the position of the diaphragm so as to control the gas flow, the actuator comprising:
• a tubular housing;
• a plunger positioned inside the housing and having an actuating extension extending outside of the housing and coupled to the diaphragm, the plunger configured to be slidable inside the housing;
• a piezoelectric body positioned inside the plunger;
• a cap fixedly attached to the housing and a stopper compressed between the cap and the piezoelectric body, wherein the stopper comprises a recess forming a clearance between the stopper and the plunger, whereby the plunger is free to slide into the clearance;
• and,
• a pre-loader applying force to the plunger so as to press the plunger against the piezoelectric body.

A valve actuator arrangement comprising:

• a tubular housing;
• a plunger positioned inside the housing and having an actuating extension extending outside of the housing and coupled to a diaphragm, the plunger configured to be slidable inside the housing;
• a piezoelectric body positioned inside the plunger and preloaded by over 700N;
• a cap fixedly attached to the tubular housing and a stopper compressed between the cap and the piezoelectric body;
• electrical leads attached to the piezoelectric body, the electrical leads hermetically sealed by glass frit inside respective holes in the stopper and thence passing through a passage in the cap.

An actuator comprising:

• an elongated tubular housing having a first end configured for accepting a cap and a second end having an actuating opening, the cap configured to securely attach to the first end;
• a plunger situated within the housing and configured to slide within the housing, the plunger having an actuating end comprising a shoulder and an actuating extension, wherein the actuating extension is sized to fit within the actuating opening and extend outside of the housing through the actuating opening;
• at least one piezoelectric element positioned within the plunger and abutting an interior wall of the actuating end of the plunger;
• a stopper positioned between the cap and the piezoelectric element;
• electrical leads attached to the at least one piezoelectric element;
• at least one preloading element positioned inside the housing and compressed between the second end of the housing and the shoulder;
• bellows sealed at one end to the plunger and at a second end to the cap;
• and,
• inert gas within the plunger and sealed by the bellows.

An actuator comprising:

• an elongated tubular housing having a first end configured for accepting a cap and a second end having an actuating opening, the cap configured to securely attach to the first end;
• a plunger situated within the housing and configured to slide within the housing, the plunger having an actuating end comprising a shoulder and an actuating extension, wherein the actuating extension is sized to fit within the actuating opening and extend outside of the housing through the actuating opening;
• at least one piezoelectric element positioned within the plunger and abutting an interior wall of the actuating end of the plunger;
• a stopper positioned between the cap and the piezoelectric element, and bellows attached at one end to the plunger and at a second end to the stopper, and inert gas within the plunger and sealed by the bellows;
• electrical leads attached to the at least one piezoelectric element;
• and,
• at least one preloading element positioned inside the housing and compressed between the second end of the housing and the shoulder.