초록 ▼

Apparatus for combining fluid flows in variable proportions is adapted for blending an active constituent gas and a diluent gas to calibrate gas analyzers used in monitoring pollution. Diluent gas passes from source 34 through a downstream differential pressure regulator 17 and a constant flow restr

Apparatus for combining fluid flows in variable proportions is adapted for blending an active constituent gas and a diluent gas to calibrate gas analyzers used in monitoring pollution. Diluent gas passes from source 34 through a downstream differential pressure regulator 17 and a constant flow restrictor 12 to outlet 14 which communicates with control port 20 of regulator 17. Active gas passes from source 35 through differential pressure regulator 23, through three fixed parallel flow restrictors 22, 29 and 30 to combine with the diluent gas upstream of restrictor 12. Control port 26 of regulator 23 communicates with the input to restrictor 12. Switching of valves 31, 32 and 33 varies the rate of flow along conduit 16 and hence the proportions of gases combined upstream of restrictor 12. Regulator 23 maintains flow along 16 substantially constant for given valve settings, and regulator 17 maintains flow along outlet 14 substantially constant despite changes in flow rate in the conduit 16.

대표청구항 ▼

A method of combining fluid flows comprising the steps of: passing a flow of a first fluid through a controlled variable flow restriction; combining the output of said first fluid from the controlled flow restriction with a flow of a second fluid; passing the combined flow of the first and second fl

A method of combining fluid flows comprising the steps of: passing a flow of a first fluid through a controlled variable flow restriction; combining the output of said first fluid from the controlled flow restriction with a flow of a second fluid; passing the combined flow of the first and second fluids through a main flow restriction; sensing the pressure of said combined flow downstream of said main flow restriction; varying the rate of flow of the second fluid relative to the rate of flow of the first fluid so as to vary the proportions of the fluids combined together; and varying said controlled variable flow restriction, and thereby the flow of said first fluid, in dependence upon said sensed pressure at the output of said main flow restriction in such a manner as to maintain substantially constant the pressure across the main restriction and to maintain substantially constant the rate of flow of the output of combined fluids from the main restriction despite changes in the rate of flow of the second fluid which is being combined with the first fluid.