WATER-COLUMN BACK-PRESSURE PNEUMATIC GAUGE MECHANISM

Work 1 to be checked is placed on base 2, and above the work, with a certain clearance, measuring head 3 is rigidly mounted. This head is connected by tube 4 to measuring chamber 6 into which compressed air enters through small orifice (restrictor) b. Tube 7, immersed in water chamber 8, serves to maintain constant air pressure. Surplus air is evolved as bubbles. Manometer 5 is connected to measur…