| 摘要 |
PURPOSE:To prevent a quenching head from breaking down owing to the sudden interception of supply of cooling water by connecting an air conduit having an opening-closing valve on the down side of the control valve of a water supply pipe and introducing air once water supply is interrupted. CONSTITUTION:Once the end surface of a steel pipe P matching with a quenching head 1 is brought into contact with the end surface of a nozzle 15, the operating lever 14 of a hydraulic cylinder 13 moves forth, and the forward movement of a movable element 20 allows a clamping arm 24 to rotate inward, thereby securely clamping the steel pipe P and nozzle 15 securely with the tip part of the arm. Then, a control valve 31 is opened to feed cooling water from a hydraulic pressure source by pressure, and the water flows into the steel pipe P to cool its internal surface. At this time, the valve 41 of an air conduit 4 is closed. On quenching, the control valve 31 is closed to interrupt the water supply and the valve 41 is opened to introduce air into the water supply pipe 3 and a cylindrical body 12 from the air conduit 4. Thus, a vacuum is never produced in the quenching head 1, which is then prevented from breaking down. |
