| 摘要 |
<p>A valve construction for high pressure gases, allowing rapid opening and closing, includes a main body with inlet (12) and outlet (14) passages, and a guide sleeve (20) having a primary (16) and a secondary piston (18) slidably mounted within the sleeve, the primary piston being adjacent a closure (22) at one end of the sleeve, and the secondary piston being at the end of the primary piston which is remote from the closure. The secondary piston supports a seal (44) for closing the gap outlet passage when the secondary piston is remote from the closure. The secondary piston has an axial passage with an elongate member (58) movable therein, the elongate member being fixed to the primary piston. A valve means (60) is provided between the axial passage and the elongate member, the valve means being open when the bleed orifice (48) is closed. A peripheral seal (92) between the secondary piston and the sleeve acts to restrain the axial movement of gas. An access passage (80) connects the periphery of the secondary piston with a location on the axial passage, while a passage way (84) in the secondary piston connects the region between the first and second pistons with the bleed orifice chamber. An electrical coil (24) acts to generate a magnetic field. The valve construction thus defined is equilibrium when the coil is de-energized, the seal means closing the gas outlet passage, the closure portion closing the bleed orifice, and the primary piston being furthest remote from the closure. When the coil is energized, the primary piston moves toward the closure until the valve means closes, lifting the closure portion off the bleed orifice and permitting gas to escape from around the primary piston, through said passageway, and out the bleed orifice, thus resulting in an increase in the pressure differential across the peripheral seal. <IMAGE></p> |
