| 摘要 |
PURPOSE:To enable a very small quantity to be regulated by regulating without permanent deformation an opening between a plane valve body and a plane valve seat. CONSTITUTION:Gas introduced into a gas chamber GC is made to flow through an opening between a valve body 1A and a valve seat 1B, both of which have flat smooth surfaces made of hard sapphire. Air pressure is added to a diaphragm 3 in order to drive the valve seat 1B. When air pressure is not added, the valve body 1A is push-pressed to the valve seat 1B by means of a spring 4, and a state in which there is actually no gas leak. The valve body 1A rises as air pressure is added, and the flow quantity of gas increases. The valve body and the valve seat obtain highly flat smooth surfaces whose surface roughness is less than about 50mum, and the control of a very small flow quantity remains possible due to a minute opening formed by them.
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