Flow rate sensor

Abstract

A flow rate sensor high in pressure resistance has a structure to facilitate the measurement of a minuscule differential pressure for measurement of a very small flow rate. A chamber (20) is defined into a primary chamber (21) and a secondary chamber (25) by two diaphragms (31, 32) arranged in an opposed relation to each other. A fluid is passed from the primary chamber to the secondary chamber through a bypass (35) having an orifice portion (40) thereby to generate a differential pressure. The load generated by the fluid pressure fluctuations received by the first and second diaphragms is detected as a difference of displacement by a load difference sensor (50) arranged between the first and second diaphragms thereby to detect the flow rate of the fluid. Displacement limiting members (61, 62) are provided for the diaphragms or the load difference sensor so that the displacement due to the fluid pressure fluctuations received by the first and second diaphragms may not exceed a predetermined amount.

Dependencies are inferred from the claim text.