METHOD OF SOCKET WELDING OF POLYMER PIPES AT LOW AIR TEMPERATURES Russian patent published in 2023 - IPC F16L47/03 B29C65/34 

FIELD: welding of polymer pipes.

SUBSTANCE: invention can be used for socket welding of polyethylene pipes at ambient temperatures lower than those provided for in regulatory documents. Before welding, a separate heating device is installed on the pipes and fittings at the site of the future welded joint. A separate heating device consists of a flexible material such as silicone, equipped with a temperature sensor, controller and power wires. A certain voltage is applied to the heating device and the internal and external walls of the pipes and fittings are preheated. Next, a certain free cooling time is maintained (a process pause) to level the temperature field in the welding area. During the process pause, part of the heating device is removed from the inner walls of the parts being welded. Part of the device on the outer walls of the fitting remains in place. The welding process is then started through the socket terminals using a standard welding machine. After welding, a separate heating device maintains the cooling rate of the welded joint, as at permissible ambient temperatures.

EFFECT: dynamics of the temperature field in the heat-affected zone during welding and cooling of the welded joint at any low temperatures is forcibly maintained close to the temperature field during welding in a regulated temperature range, taking into account the ambient temperature.

1 cl, 3 dwg