| 摘要 |
A solenoid valve has a main body defining a gas inlet passage, a gas outlet passage, and a cavity; a core tube forming a closure for saidthe cavity so as to prevent an escape of gas; a cylindrical main piston slidably movable in saidthe cavity of saidthe main body, saidthe main piston forming a front chamber and a back chamber in saidthe main body, saidthe main piston having a gas conduit for passing the gas from saidthe gas inlet passage to saidthe front chamber and an axial hole for passing the gas from saidthe back chamber into saidthe gas outlet passage with a bleed orifice at one end of saidthe axial hole; saidthe main piston being spring biased to a closed position; a spring biased pilot piston; and an electrical coil means associated with saidthe core tube to provide a magnetic field for movements of saidthe pilot piston and saidthe main piston, so that when saidthe coil means is deenergized saidthe pilot piston closes saidthe outlet passage and causes a pressure equalization allowing saidthe return spring to push saidthe main piston to close the valve, while when saidthe coil means is energized saidthe pilot valve opens saidthe outlet passage and lowers a pressure which causes pushing of saidthe main piston to open the valve. |
| 主权项 |
1. A solenoid gas valve construction comprising:
a main body defining an inlet, an outlet and a cavity communicating with both the inlet and outlet; a tubular core comprising an inwardly directed annular flange and disposed in the cavity, a tube surrounding the core, a stop occluding the end of the tube, an o-ring mounted about the core and sealing the core to the main body; a threaded nut, a spacer, a seal and a sleeve defining, in combination with the core, a main piston chamber; a guide bushing having communication conduit holes locating circumferentially thereon, the guide bushing being in abutment at one end with the stop such that a pilot piston chamber is defined by the guide bushing, the core and the stop; a main piston comprising an end, a recess portion, and a cylindrical body, the main piston being connected to the other end of said guide bushing and, together with said guide bushing, being slidably movable in said main piston chamber; said main piston segregating said main piston chamber to a front chamber and a back chamber, said main piston further having an axial passage including a drain orifice extending therethrough providing for communication between the pilot piston chamber and the outlet, the main piston further having a cavity located at an outer circumferential portion of the main piston to communicate with the front chamber and a passage connecting said cavity to said back chamber; a pilot piston slidably movable in said pilot piston chamber; an insert, having an axial through hole and disposed in said cavity, places into said cylindrical cavity of said main piston; the diameter of the axial through hole being smaller than that of said drain, the through-hole and passage defining a gas passage from said front chamber, to said back chamber; a return spring received within said back chamber between said main piston and said inwardly-directed annular flange of said core, to urge said main piston in a direction away from said core, so that said spherical end of said main piston presses against said valve seat to close the communication between the inlet and outlet; and a pilot piston spring biasing to urge said pilot piston in a direction away from said stop of said core, so that the pilot piston presses against said drain orifice of said passage to achieve a gas-tight seal. |
