Dwyer 2000-250PA MAGNEHELIC, DIFFERENTIAL PRESSURE GAUGE, 0/250PA

• Precision litho-printed scale is accurate and easy to read.
• Red tipped pointer of heat treated aluminum tubing is easy to see. It is rigidly mounted on the helix shaft.
• Pointer stops of molded rubber prevent pointer over-travel without damage.
• "Wishbone" assembly provides mounting for helix, helix bearings and pointer shaft.
• Jeweled bearings are shock-resistant mounted; provide virtually friction-free motion for helix. Motion damped with high viscosity silicone fluid.
• Zero adjustment screw is conveniently located in the plastic cover, and is accessible without removing the cover. O-ring seal provides pressure tightness.
• Helix is precision made from an alloy of high magnetic permeability. Mounted in jeweled bearings, it turns freely, following the magnetic field to move the pointer across the scale.
• Samarium Cobalt magnet mounted at one end of range spring rotates helix without mechanical linkages.
• Calibrated range spring is flat spring steel. Small amplitude of motion assures consistency and long life. It reacts to pressure on diaphragm. Live length adjustable for calibration.
• Silicone rubber diaphragm with integrally molded O-ring is supported by front and rear plates. 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 and iridite-dipped to withstand 168 hour salt spray corrosion test. Exterior finished in baked dark gray hammerloid. One case size is used for all standard pressure options, and for both surface and flush mounting.
• Blowout plug of silicone rubber protects against overpressure on 15 psig rated models. Opens at approximately 25 psig.
• O-ring seal for cover assures pressure integrity of case.