| 摘要 |
A control system for a diffusion pump is provided which serves to protect the pump from loss of the pumping fluid, from loss of water cooling, as well as from overheating of the heater. The protective system includes a thermally responsive switch mounted on a heat-conductive bracket, and which responds to the temperature of the cooling water as well as to heat radiated from the heater to turn off the electric current to the heater when either the temperature of the cooling water or the heat radiated from the heater rises above a predetermined value. The control system also includes a heater block surrounding the heater, and which is composed of a material having a relatively low melting point as compared with the melting point of the material forming the containment vessel of the pump, so that overheating of the heater will cause the block to melt and to be displaced from the bottom of the containment vessel to reduce heat transfer to the pump. The control system also includes a further vessel filled with heat insulation material surrounding the boiler at the bottom of the containment vessel to minimize heat transfer from the heater to the cooling coils of the pump.
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