Method and apparatus for mixing two gases in a predetermined proportion

• US 4,023,587 A
• Filed: 05/13/1976
• Issued: 05/17/1977
• Est. Priority Date: 11/14/1975
• Status: Expired due to Term

• Current Assignee: Dragerwerk AG
• Original Assignee: Dragerwerk AG
• Inventors: Dobritz, Gunther
• Primary Examiner(s): Nilson, Robert G.
• Application Number:
  US05/686,658
• Time in Patent Office: 369 Days
• Field of Search: 137/7, 137/88
• US Class Current: 137/88
• CPC Class Codes: A61M 16/12 by mixing different gases
• CPC Class Codes: A61M 16/202 electrically actuated
• CPC Class Codes: G05D 11/133 with discontinuous action
• CPC Class Codes: Y10T 137/2499 Mixture condition maintaining or sensing

Abstract

A method for the control of proportion of two gases which are delivered to a mixed gas line for use for example in a respiratory breathing apparatus in which the gases are delivered to a mixed gas line from a pressure control vessel, comprises continuously monitoring the pressure in the control vessel and when the pressure therein is at an initial predetermined pressure admitting a first gas into the pressure control vessel until the pressure therein increases to a predetermined higher pressure and then stopping the admission of the first gas and initiating the admitting of a second gas into the pressure control vessel, continuing to admit the second gas until a predetermined additional higher pressure is achieved in the pressure control vessel, discontinuing the admission of the second gas when the predetermined additional higher pressure is reached and initiating the withdrawal of the mixed gas through the mixed gas line, continuing to withdraw the mixed gas through the mixed gas line until an initial pressure is again reached in the pressure control vessel at which time the complete process is repeated again. The apparatus includes a first control valve in a first gas supply line to the pressure vessel and a second control valve in a second gas supply line to the pressure control vessel. A third control valve is arranged in a mixed gas delivery line which connects the pressure vessel. All of the three valves are connected by a control device which is responsive to the pressure in the pressure vessel and the individual control valves are set for opening and closing at different control pressures so that the inflow of the first and second gases and the delivery of the mixed gases will be continuously controlled thereby.

Claims

1. An apparatus for mixing two gases in a predetermined proportion, comprising a pressure control vessel, a first line for supplying a first gas connected to said pressure control vessel, a first gas control valve in said first connecting line, a second connecting line for the supply of a second gas connected to said pressure control vessel, a second gas control valve in said connecting line, a mixed gas line for delivering the mixed gas connected to said pressure control vessel, a third gas control valve in said mixed gas line, each of said first, second and third control valves being set for opening and closing at separate distinct pressures, and control means connected to said pressure vessel and to each of said first, second and third valves to open and close said valves in accordance with the set values of pressure for opening and closing, said valves being set so that an initial pressure in said pressure control vessel causes the opening of said first valve to permit inflow of a first gas through said first gas connecting line to said pressure control vessel, said second valve being set to open and said first valve being set to close upon the increase of the pressure in said pressure control vessel to a higher pressure above said initial pressure, said second valve being set to close and said third valve being set to open when a predetermined additional higher pressure has been reached in said pressure control vessel, said third valve being set to close and said first valve being set to open once again when said initial pressure returns to said pressure control vessel.

2. A device according to claim 1, including an alarm connected to each of said first and second valves and to said control means which is operable on failure of said first and second valves to switch in response to said control means.

3. An apparatus according to claim 1, wherein said first and second valves comprise a switch-over valve, said first and second connecting lines including first and second supply lines connected to said switch-over valve and a single line connected from said switch-over valve to said pressure vessel, said thrid valve comprising a switch-over valve, said third line including a connection between said pressure valve and said second switch-over valve and a connection from said second switch-over valve forming a mixing gas line, said connection from said first switching valve to said pressure valve including a connection from said first switching valve to said second switching valve and said connection of said second switching valve to said pressure vessel.

4. A device according to claim 3, wherein said first switchover valve switches at the initial pressure to the first supply line and at an actuating pressure to the second supply line and said second switchover valve switches at an initial pressure to the connection between said first and second switchover valves and at a final pressure to connect said pressure vessel to said mixing gas line.