| 摘要 |
<p>PURPOSE: To protect a device from excess pressure positively and with good reproducibility even when the excess pressure is low by allowing a valve to abut on a nozzle connected to a space in a device by a specified force caused by air pressure independent of the pressure in the space. CONSTITUTION: With an excess pressure protection device, a substrate 1 is arranged and in a cover 3 a valve 2 is arranged, and above the valve, cavities 13, 14 are defined by ribs 15. A tube 9 provided in the substrate 1 is connected to vacuum spaces of epitaxy reactor, etc., and a tube 8 of the cover 3 is connected to atmospheric pressure. Vacuum in an area between two seals 4, 5 causes the valve 2 to abut on a valve seat of a second nozzle 7 for adjusting pressure between atmospheric pressure and the initial vacuum, and further to abut on the ribs 15. The vacuum in the vacuum reservoir is fixed to a half of normal atmospheric pressure, and when an excess pressure of about 0.05 bar or more is applied in the tube 9 the valve 2 is separated from the substrate 1 to exhaust excess pressure gas from the tube 8. Thus a device can be positively and with good reproducibility protected from even low excess pressure.</p> |
