An important aspect in calculating the geometric design parameters of welded joints with embedded heaters is the depth of the insertion tube. It consists of:
from the welded zone, ie surface of a homogeneous connection with the PEX pipe fitting. Simplistically we can say that the longer the welded zone, the greater the durability and reliability of welded joints in practice;
from internal and external cold zones, whose mission is to:
*retention of melt occurring in the welding process;
*compensation for the small offset and angular, due process of installation;
*alignment or compensation of deviations form the pipe from the ideal condition, such as ovality, cone-shaped tube ends or cut the pipe, made at an angle different from 90 °, which also caused mounting conditions at the site.
Not affected by cold temperature impact zone “retard” the spread of the melt. PEX melt during welding, cooled in cold areas, so that at the junction creates a uniform pressure of the melt. The parameter “pressure of the melt is in addition to the time of welding and welding temperature value, which determines the quality of the weld. Lack of retention of welded pressure can lead to the exit of the melt from the zone of welding, degrade the quality of the joint pipe-PEX fitting and therefore unacceptable.
The longer the cold zone, the better it will be compensation for the stress in bending, which arise, for example, when using pipes in the bay. These stresses do not affect the zone of welding, because tube is aligned through the long cold zones and, consequently, greater depth of insertion sleeve.
These requirements are reflected in the design of long sleeves Frialong, which is used primarily for welding pipe in the bay.
Special attention should be inside the cold zone. Typical phenomena of deviation form the pipe ends of a round are compensated through this zone. In the case where the pipe at the construction site was carried out not at a right angle, disconnect the pipe sections will be equalized through a great length of the cold zone. Therefore, the zone of welding a negative impact will not be, and the weld quality is guaranteed.
The direct impact on the quality of the connection has a performance area of the heating element.
