The chambers of cylinders 3 and 4, containing bellows 1 and 2, are connected to the spaces whose difference in pressure is to be measured. Cylinders 3 and 4 are joined by stem 5. Stem 5 is subject to the action of weight 7, transmitted through lever 6 which turns about fixed point A. Weight 7 develops the counterbalancing moment. The movement of stem 5 depends upon the difference in pressures in cylinders 3 and 4. This difference is determined by setting weight 7 along lever 6 to the equilibrium position. Pushers 8 and 10, and lever 9 enable the equilibrium position of lever 6 to be accurately determined.
$4060$EHP,M$