| 摘要 |
<p>The invention relates to butt welding and is particularly concerned with the provision of self-determined cooling times during which pipe ends must remain clamped in the machine to ensure the creation of an effective weld. Most effective butt welding machines are already known such as are described in British Patent No. 2191976, but even machines of this sophistication leave largely to the discretion of an operative the degree of time that the machine must be left after the welding stage and before the clamps can safely be removed. Almost inevitably this results in the pipes being clamped in the machine far longer than is actually necessary and the object of the invention is to provide for shortened cooling times that are self-determined by the machine and by ambient temperature conditions. The invention involves the provision of control means employing parameters sensed and/or measured to limit the cooling stage to a duration no more than is required having due regard to ambient temperature conditions and the amount of heat input to the pipe ends during the heating and/or bead-up stage.</p> |
