Patent ID: 8754348

Claim:
A plasma cutting system, comprising: a gas supply system constructed to provide a pressurized gas to a plasma torch; and a proportional valve configured to regulate flow of the pressurized gas, the proportional valve comprising: a body; a valve seat positioned within the body and defining a valve orifice; a plunger having a mating surface on a first end and a pressure receiving surface on an opposite second end, the mating surface configured to mate with the valve seat and the valve orifice; an inlet configured to receive the pressurized gas and to distribute the pressurized gas to the valve orifice and the pressure receiving surface of the plunger; an electrical solenoid mounted in the body and configured to electro-magnetically translate the plunger; and a valve chamber surrounding the plunger and connecting the mating surface of the plunger and the pressure receiving surface of the plunger to enable the pressurized gas to apply pressure to the pressure receiving surface of the plunger to urge the plunger toward the valve orifice; wherein the pressurized gas urges the plunger toward the valve orifice when electrical power is reduced to the electrical solenoid.