Suppose that I want to transport gases in a tube in only one direction. Can a liquid check valve be used in place of a gas check valve or is there a specific reason to use only a gas check valve?


2 Answers 2


No, liquid check valves function on density, viscosity or velocity or a combination and the mass is taken into account - gas check valves are designed to deal with a fluid 700 or more times less dense than a liquid.

Some gas check valves will function with a liquid - a check valve designed for blowing up party baloons for example will work with a liquid at low pressure but not high pressure.

  • $\begingroup$ Lubrication of the valve is often an issue. Liquid valves will use the working liquid to lubricate and seal themselves. Gas valves, when not using soft material (rubber etc) will use some lubricant that is likely to be washed off by liquid. $\endgroup$
    – SF.
    Jun 6, 2017 at 9:11

Industrial valves are ( or were ) marked W O G . Meaning they are suitable for water, oil, and gas, ( not gasoline .). It is up to the user to determine if the valve will function in his particular application.

  • $\begingroup$ could that be " Water Oil Gasoline " ? See here : flomatic.com/assets/pdf_files/literature/… at the top of page 3?? $\endgroup$
    – Solar Mike
    Jun 5, 2017 at 21:43
  • $\begingroup$ That seems to contradict Solar Mike's post. Are you sure about this information? $\endgroup$ Jun 5, 2017 at 22:39
  • $\begingroup$ "gas" is a common contraction for "gasoline." Given the context of this question, it would be better better to say "gasoline" to avoid any confusion with the term gas. $\endgroup$
    – user16
    Jun 6, 2017 at 12:06
  • $\begingroup$ Having been on ASTM and API valve committees , I believe my statement is correct. $\endgroup$ Jun 6, 2017 at 20:37

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