| 摘要 |
<p>A vacuum exhaust valve is disclosed for vacuum-operated exhaust lines of chemical vapor deposition equipment, which includes a sheathed heater (14) made of hollow metal tube spirally formed into a coil and heating wire inserted into the spiral tube, the sheathed heater (14) being mounted to sealingly shroud a reciprocally disposed valve disk (5). The sheathed heater (14) is provided inside a bellows (6) that is mounted to shield the core valve portion against the flow of chemical vapor flowing through the valve disk (5). Also, the sheathed heater (14) is vertically expandably disposed for synchronization with the vertical movement of the valve disk (5) as the latter is driven by an actuator (4) to move into abutting contact or away from a valve seat (7) between an inlet port (1) and outlet port (2). In addition, a sheathed thermocouple (18) is mounted inside the sheathed heater (14) for measuring the temperature of the latter and operatively connected to a temperature control device (20) for controlling the sheathed heater (14). With this arrangement, the temperature of the bellows (6), valve disk (5) and valve seat (7) is kept at a predetermined stable temperature range so as to minimize adhesion or deposition of chemical substance to their surfaces. <IMAGE></p> |
