Ratio controller for gases

Claim 1

The device of claim 1 wherein said means for further adjusting both said differential pressures comprise means for generating a pressure signal related to the demand as expressed in the pressure in said common output conduit and said means for setting the ratio comprises a linked pair of valves having means for varying the areas of two main orifices so that one is enlarged while the other is diminished, each said valve having an inlet with a restricted orifice into which said pressure signal is sent and a delivery conduit downstream of said restricted orifice and upstream of said main orifice, said delivery conduit transmitting an output pressure controlling one said differential pressure.

Claim 2

A device for taking two gases at substantially identical regulated supply pressures and for delivering a mixture of said gases at a desired ratio, including in combination: two flow controllers, one for each gas, each having a housing and first, second, and third diaphragms cooperating to provide first, second, third, and fourth chambers, each having an inlet and said fourth chamber only having an outlet, said first chamber being connected to its gas at the supply pressure to bear against said first diaphragm, said third chamber being between said second and third diaphragms and open to the atmosphere, while said fourth chamber is on the opposite side of said third diaphragm from said third chamber, said third diaphragm being movable away from and toward said outlet to control the flow therefrom, said diaphragms being joined as an assembly for common movement according to the relative pressures in said chambers, the inlet to said fourth chamber having a fixed orifice and connected to the respective gas at its supply pressure, there being a pressure differential across said fixed orifice, a pressure controller having a housing and fourth and fifth diaphragms with different effective areas joined in an assembly, and providing fifth, sixth, and seventh chambers, said fifth chamber being open to the atmosphere and having spring bias means thereon bearing against said fourth diaphragm, the pressure applied to the sixth chamber between said fourth and fifth diaphragms creating a force proportional to that pressure and opposed by the force of said spring, means for applying the pressure of the output mixture to said sixth chamber, nozzle means leading into said seventh chamber and an outlet from said seventh chamber to atmosphere, a restricted orifice means connected to the supply pressure of one of said gases and to said nozzle, a passage leading to an outlet from a point in between said orifice means and the exit from said nozzle into said seventh chamber, said diaphragm assembly moving toward and away from said nozzle to admit gas or to block it from said seventh chamber and thereby change the pressure in said passage, and ratio setter means comprising two precision spring-loaded metering valves, each with an orifice between an inlet and an outlet, said outlet passing to the atmosphere, means for simultaneously driving said valves in opposite directions, so that as one is opened wider the other is being closed, the stem of one valve being extended and provided with a knob for manual setting of said ratio by setting the area of said two valve orifices, and each valve having an inlet connected to said passage in said pressure controller and having an inlet orifice and a second outlet on the same side of said orifice as said inlet and connected to said orifice and to said inlet on the opposite side of said inlet orifice from said passage, said second outlet being connected to the inlet to the second chamber of the corresponding flow controller.

Claim 7

A method for mixing two gases at any desired ratio and for maintaining any such ratio once set over a wide range of outlet pressure settings and during either continuous or intermittent delivery of the mixture, in a delivery stream comprising: supplying each gas at substantially the same regulated pressure to a main stream and to a reference pressure station, withdrawing from one said main stream a branch stream and reducing the pressure of said branch stream, while varying the amount of pressure to which it is reduced according to the variations in the instantaneous pressure of said delivery stream, then dividing said branch stream into two control streams, adjusting the pressure of each said control stream relative to the other, by sending each through a fixed restriction and then bleeding it an adjustable amount, to provide a desired pressure ratio between the unbled portions of the two control streams, applying said unbled portions to said reference pressure stations to oppose each reference pressure with a respective control stream, restricting the flows of both said main streams through fixed restrictions to reduce their pressures, and opposing them at their reduced pressures to their respective reference pressures, so that each said reference pressure is opposed both by its associated main stream at said reduced pressure and by its respective unbled control stream portion, and then flowing said main streams at their reduced pressures into said delivery stream, each at a rate depending, first, on said ratio between the unbled portions of said control streams and, second, on the differential pressure between its said reference pressure and said reduced pressure and thereby on the instantaneous demand for the mixture.

Claim 9

A device which receives two gases at substantially identical regulated supply pressures and delivers a mixture of said gases at a desired ratio, including in combination: a common output conduit for said mixture; two flow controllers, one for each gas, each having means for establishing a reference pressure based on the supply pressure of that gas, said flow controller having a fixed orifice connected directly to said supply pressure gas, and providing each flow controller with a stream of that said gas at a pressure lower than said supply pressure, thereby setting up a differential pressure with respect to said reference pressure, means connected to said common output conduit for generating from one said gas at its supply pressure a signal pressure as a function of the instantaneous demand for said mixture, as indicated by the instantaneous pressure of said mixture in said common conduit, a linked pair of valves having means for varying the areas of two main orifices so that one is enlarged while the other is diminished, each said valve having an inlet with a restricted orifice through which said signal pressure is sent and a delivery conduit downstream of said restricted orifice and upstream of said main orifice for conducting the pressure downstream of each said restricted orifice to one said flow controller as a signal pressure for that gas and hence ratioing said signal pressures, said signal pressures governing the flow of each gas from said flow controller into said common output conduit in accordance with the effect of said signal pressure on said reference pressure, said valves thereby setting the relative flow rates at which the two gases flow into said common output conduit.