| 摘要 |
PURPOSE:To prevent a motor from stopping running and to facilitate pulling back of an outer tube manually even if the motor stops running, by installing an injection medium pressure reducing means which is operated in case an overload condition occurs. CONSTITUTION:When an overload signal L from a current relay 19 is inputted, a control box 32 reduces the pressure of an injection medium by feeding an instruction signal to a pressure reducting valve 5, and the pressure of a medium is also reduced to below a pressure under which an overload relay is operated. If, under this state, a soot blower is in forward movement, a plugging signal is fed to a motor to move backward the soot blower, and if it is in backward movement, it is moved backward as it is. This permits backward movement of the soot blower by means of the motor but not of a manual operation even if the soot blower is brought to an overload state. |
