摘要 |
<p>An automatic vent valve and method for use is provided equalizing the pressure in at least two lines. A housing has a first piston that compresses a bias device when the second pressure source supplies sufficient pressure. Upon a sufficient reduction in pressure the first piston releases a second internally held coaxial piston to allow fluid to flow from a first pressure source towards a second pressure source, thereby equalizing the pressure between the two pressure sources.</p> |