New snap-action air relay pressure switches
Family eliminates problems typical of throttling band designs, say K-Tek. New pilot-operated, snap-action pneumatic switch has a patented, snap-action mechanism that eliminates problems normally associated with throttling bands. This new-design air relay can be fine-tuned for accurate increasing or decreasing action. It has a narrow deadband, as low as ...<br/>
K-Tek has announced a new pilot-operated, snap-action pneumatic switch from Beta N.V., its subsidiary in the Netherlands. The switch features a patented, snap-action mechanism that eliminates problems normally associated with throttling bands. This new-design air relay can be fine-tuned for accurate increasing or decreasing action. The switch features a narrow deadband, as low as 10 mbar, and supports pilot supply and signal pressures up to 7.0 bar.
K-Tek says the new units are designed for valve control, bleed-off shut-down, or alarm applications, even in Zone 0 hazardous locations. The switch is available in two configurations: Type SA for normally closed (N.C.) and Type SB for normally open (N.O.) operation.
"A high-quality, self-aligning diaphragm piston sensor is at the heart of the Beta air relay switch," says Winston Landymore, Beta product manager at K-Tek. "Limited piston travel translates pressure at the diaphragm directly to actuation of the microswitch. This means no intervening linkages or mechanisms, and full protection against high over-range pressures up to 400 bar."
The unit’s piston sensor is isolated from the process fluid by a diaphragm and static O-ring seal, retained by a process connection port. These process wetted parts are available in a wide range of materials, eliminating the need for costly chemical seals. Process connections are available in 316 stainless steel, Monel, and aluminum. Diaphragm and O-ring material choices include Buna-N, EPR, Kalrez, neoprene, Teflon, 316 stainless steel, tantalum, Viton A, and Monel. A venting port avoids overpressure in the enclosure.
Also read: Safety: Tale of Two Applications .
—Edited by Peter Welander, process industries editor, PWelander@cfemedia.com ,
Control Engineering Process Instrumentation & Sensors Monthly
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