JPS5459184A - Differential pressure detector - Google Patents

Abstract

PURPOSE: To achieve the prevention of overpressure and the reduction in temperature static pressure errors by separating medium to the partition wall side and the element side with one of elastic bodies when pressure above a detection range is applied thereby preventing the movement of the medium and absorbing the fine movement of the medium on the element side with the other elastic body.

CONSTITUTION: Pressures Pa, Pb are applied in holes 39a, 39b, then diaphragms (partition walls) 36a, 36b displace and pressure media 38a, 38b move. When the pressure Pa exceeds the elastic limit of a pressure sensitive element 35, the pressure is received on the outside face of a bellows 65a and the inside face of 65b by way of the partition wall 36a, medium 38a, whereby the medium 38a is moved leftward and is sealed among the partition wall 36a and O-ring 56a, the outside face of the bellows 65a, the inside face of 65b and the element 35. Even when the O-ring is crushed as the movement of the medium stops and overpressure is applied, the bellows 65b becomes a pressure displacement body for protection of the element after preventing overpressure, thus minimizing the pressure change to be exerted upon the element 35. At this time, the thermal expansion and shrinkage of the medium 38a having been sealed may be prevented by the bellows 65a, 65b even if temperature changes

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