High pressure switches have extremely high proof pressure limits so that they can function in pressure systems that reach high pounds per square inch (psig). In addition, they can be useful in pressure systems that operate within normal pressure ranges, but could potentially experience temporary pressure surges or spikes that would cause the systems to exceed normal psig. While typical pressure switches would fail under such conditions, high pressure switches will maintain proper operation and allow for pressure control to be constantly maintained.
Advantageous for diverse applications, high pressure switches maintain pressure control in industries such as: the agricultural industry for use in equipment and machinery; marine industry for off-shore exploration; the defense industry for applications in which the conditions are unstable; and the HVAC industry for measuring and controlling cooling duct pressures. High pressure switches often offer additional features such as explosion or waterproof, due to the intense pressure conditions that they are required for. Most often composed from materials such as aluminum, stainless steel, Monel, hastelloy and steel, high pressure switches should have characteristics such as durability and tensile strength, with high corrosion-resistance desired, if not absolutely necessary.
High pressure switches can operate anywhere from 1 psig to 10,000 psig or more, with 4,500 to 7,500 psig being about the average maximum proof pressure. High pressure switches can be actuated through diaphragms, pistons or piezoelectric crystals, although they are not common. Diaphragm-actuated high pressure switches are probably the most common, and are actuated as the result of pressure fluctuation. The actuation is triggered when the flow exceeds the set point and the diaphragm is pushed open, causing the medium to flow through. The next common would be piston-actuated high pressure switches, in which the piston functions in much the same way as a valve, opening or closing in response to high pressure flow. Lastly, piezoelectric-actuated high pressure switches are actuated when the piezoelectric crystal is pressed or released, causing it to produce a voltage. High pressure switches are primarily a form of differential pressure switch, which serve to measure or regulate between two points of differing pressure and actuate based on a set point. However, they may also be vacuum or solid-state switches. While vacuum switches regulate the pressure between two closed cavities by converting a negative pressure signal to an electrical output, solid-state switches operate electronically and do not require moving parts; instead, they function by opening or closing pressure switch circuits.
High Pressure Switches - Tecmark Corporation