Mid-West 109-QE-00-OO-15P Differential Pressure Gauge with 316 Stainless Steel Body and Stainless Steel Internals, Bourdon Tube Type, 1% Full Scale Accuracy, 6" Dial, 1/4" FNPT Back Connection, 0-15 psid Range, 1500 psig SWP

Mid-West Instrument bourdon tube type differential pressure gauge. Model 109 System pressure is applied to the inside of a slightly flattened arc- shaped tube. As pressure increases, the tube tends to restore to its original round cross-section. This change in cross-section causes the tube to straighten. Since the tube is permanently fastened at one end, the tip of the tube traces a curve that is the result of the change in angular position with respect to the center. Powered by a test quality Bourdon Tube assembly, the assembly is encapsulated in a high pressure chamber that is fitted with a pressure connection to the inside of the Bourdon Tube and a second connection to the pressure chamber. Model 109 assembly incorporates a bi-directional relief valve which provides over-pressure protection in both directions. When over-pressured from the high side, the valve is opened by a mechanical stop as the sensing element deflects to its maximum travel. When over-pressured from the low side, the spring-loaded valve opens when the differential pressure exceeds its maximum rating. The opening of the valve in either direction equalizes the pressure and protects the unit. 316 Stainless steel body material. Stainless steel internal metal part. Buna-N seal material. 1/4-inches FNPT back connections (stainless steel), 6-inches uni-directional round dial, weather resistant engineered plastic case, accuracy +/-1 percent full scale (ascending). Shatter resistant acrylic lens.