| 摘要 |
<p>In a valve unit having an ON-OFF switch constituted by a valve, the associated valve seat and an insulation layer, the layer is made of a compound consisting of a specific metal and a specific reaction gas and the layer is coated on the outer surface of the valve in such a way that its electrical resistance increases progressively from the inner surface closest to the valve to the outer surface destined to make contact with a guide member of the valve.</p> |
