| 摘要 |
<p>A valve housing is provided with an interior passage therethrough with the passage having two spaced apart valve seats; a first check valve member for engaging the first valve seat has a valve stem movably carried in a hollow shaft; the second valve member is itself provided with a tubular stem having an open end and which is slidably fitted on the exterior of the hollow shaft; separate coil springs are provided for urging each valve member toward a closed position on the respective valve seat whereby the each valve member is operable independently of the other valve member.</p> |
