Pressureloss flow meter and apparatus for flow control using such a flow meter

摘要

1. Device for measuring a gaseous fluid flow, of the type using a hollow cylindrical element (93, 93_d) placed in a housing body (11_c, 11_d, 11_e) which is also cylindrical, defining between them an annular channel (20_c, 20_d, 20_e) of small radial dimension for the said gaseous fluid which flows in a laminar pattern, and comprising means for working out a flow rate measurement value which is proportional to the product P_m x DELTA P of the said pressure differential DELTA P between the upstream and downstream ends of the annular channel (20_c, 20_d, 20_e) and the absolute pressure P_m sampled across the housing body (11_c, 11_d, 11_e), characterized in that the cylindrical element (93, 93_d) defining the inside of the annular channel (20_c, 20_d, 20_e) is fixed and completely immobilised in its housing body (11_c, 11_d, 11_e) and in that the means for measuring pressure, in particular differential pressure, samples the pressure at the ends of the channel (20_c, 20_d, 20_e) through upstream (90, 90_d, 90_e) and downstream (100, 100_d, 100_e) perforations in one of the elements defining the annular channel.