| 摘要 |
PURPOSE:To enable a device to withstand high temperatures and to prevent a cooling liquid from unnecessary loss by a method wherein a sensor is installed at an end of an inner tube wherein temperature is relative low and the sensor detects the expansion and shrinkage of the inner tube for the control of the flow of the cooling liquid. CONSTITUTION:A cooling means 31 is provided with sensors 38 and 39 including microswitches 36 and 37 parallelly connected across a power source 35 and solenoid valve 34. When an inner tube 18 expands along the axial direction with the temperature on the increase after the starting of the laser device, the sensors 38 and 39 are freed from a pressing force, which causes them to close, one after the other or simultaneously. Under the condition, cooling water begins to flow, allowing the device to go into a normal operation. During the operation, though the temperature rises at the middle of the inner tube 18, the microswitches 36 and 36 are prevented from damage because temperature is not high at both ends. When the laser device is stopped, the cooling water flows on, with the temperature of the inner tube 18 remaining high for some time. When the temperature lowers enough, the two sensors 38 and 39 becomes open under pressure, which closes the solenoid valve 34 for the stoppage of the supply of the cooling water. |
