| 摘要 |
<p>PURPOSE:To save power consumption by providing a variable-speed control device so as to regulate the rotational speed of a pump to set lower limit of speed at the time of no-load running and to a set upper limit of speed different for each material to be rolled at the time of normal load running in controlling the operation of pump. CONSTITUTION:When the front tip of a material to be rolled, delivered from a roughing mill 1, is detected by a pump-accelerating metal detector 7, a process computor 11 sets the upper speed-limit of a pump 14 at the time of normal load running in accordance with the kind of steel and size, etc. of material. Next, a variable-speed control device 12 drives a motor 13 of pump 14 at an instructed upper speed limit. Further, when the run-out of the tail end of material is detected by a load cell 91 of the 1st finishing mill 4, the device 12 drives the motor 13 at a set lower speed-limit (about 30% of rating) at the time of no- load running, and closes a solenoid on-off valve 17 for spraying. In this way, the power consumption is remarkably saved in both cases of normal and no-load runnings.</p> |
