What is the design and working principle of differential pressure gauge?
Differential pressure gauge is a device for measuring pressure differences. It is also used to measure the level of liquids and the flow rate of liquid steam or gas by pressure difference. Differential pressure gauges can be liquid and mechanical. An example of a mechanical differential pressure gauge is shown on the illustration.
The sensitive element of the differential pressure gauge is a membrane block, consisting of two or four membrane boxes 10, screwed on both sides into the plate 11 and tightened between two covers 9 and bolts 8. In this case, two chambers are formed:
positive (lower) - between the bottom cover and the plate;
negative (upper) - between the top cover and the plate.
Each of the membrane boxes is welded from two membranes, the profiles of which coincide in direction. The internal cavities of the membrane boxes communicate with each other through a hole in the pillow and are filled with distilled water through the nipple 12. Pressure is supplied through impulse tubes 7, on which two shut-off valves 1 and an equalizing valve 2 connecting them are installed. The core 6 of the differential transformer 5, closed by a cap 4, is connected to the center of the upper membrane. The core is located inside the separating tube, in order to exclude the effect of gaps, a spring 3 is installed
