| 摘要 |
A gas valve which is particularly useful in a laser gas fill system requiring repeated fillings includes a conduit positioned between high and low pressure gas regions. Within the conduit is a restriction, and this restriction is closed by a meltable solid material. When the valve is to be opened, heat is applied to the meltable solid material, either internally or externally, causing at least some of the material to flow and allow the passage of gas from the higher pressure region to the lower pressure region. When the pressure between the two regions has substantially equalized, or at least the pressure differential has greatly diminished, surface tension associated with the restriction in the conduit pulls the liquified material back into place to close and reseal the valve, at which point heat application is dicontinued so that the material again becomes solid. The geometry of the restriction is such that all or substantially all of the liquid material will return essentially to its original position, allowing the valve to be used in repeated on/off cycles. Also, the valve geometry and heat application are such a high pressure differential will not cause the liquified material to blow away from the valve due to high velocities.
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