Calibrated range spring is a flat leaf of Swedish spring steel in temperature compensated design. Small amplitude of motion assures consistency and long life. It reacts to pressure on diaphragm. Live length adjustable for calibration. It is locked and sealed in position with a sealing plate and retaining ring.
Diaphragm motion is restricted to prevent damage due to overpressures.
Die cast aluminum case is precision made. Iridite-dipped to withstand 168 hour salt spray test. Exterior finished in baked dark gray hammerloid. One case size used for all standard pressure ranges, and for both surface and flush mounting. Blowout plug of silicone rubber protects against overpressure on 15 PSIG rated models.