| 摘要 |
<p>A delay valve (10) has a body defining an enclosure (14), with a separating plate (16) and diaphragm operator (22) therein to define an input (18), output (20) and third (24) chamber. The input (18) and output (20) chambers are adjacent, and separated by the separating plate (16). This plate (16) defines an aperture (30), an umbrella valve opening (26) and a port (28), all of which communicate between the input (18) and output (20) chambers. A stem (40) and seal (42) arrangement is affixed to and operable by the diaphragm operator (22) against the bias force of a spring (44), to seal communication through the port (28) at and above a pressure differential between the output (20) and third (24) chambers. As the input (18) chamber vacuum decreases, the output (20) chamber vacuum level likewise decays through the aperture (30) at a relatively slow rate. When the pressure differential between the output (20) and third (24) chambers is inadequate to overcome the bias force of the spring (44), the port (28) opens and thus produces equilibrium between the input (18) and output (20) chambers. This delay valve (10) thus rapidly returns to an equilibrium position and is again ready to commence controlling without awaiting a slow decay return to equilibrium.</p> |
