If you’re not sure, ask: When this type of valve is welded to a pipe, will it damage the plastic sealing surface of the valve?
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If you don’t understand, just ask: This type of valve is used in heating hot water pipelines; I’ve already asked the experts on this forum for advice before. Now, there is one more question I’m not sure about: when this type of valve is welded to a pipe, will it damage the plastic sealing surface of the valve? It seems that the weld seam is still too close to the PTFE sealing surface of the ball valve. It is recommended that experienced teachers give an explanation:
Such welded valves usually come with sleeves (extended tubes).
It could also be a hard seal; if it is a soft seal, intermittent welding can be employed
The temperature rise caused by the heat transferred from the weld metal with low wire energy to the base material is not sufficient to affect the sealing material; this has been taken into account by the designers when selecting the materials
. The manufacturer will take that into account. Normally, proper welding does not cause damage to the valve core. If welding might damage the valve core, the manufacturer will provide special instructions. To protect the components inside the valve body from damage caused by thermal shock during welding or heat treatment, it is necessary to control the temperature for some valves. There are two ways to address the adverse effects of temperature on valves during welding: one is to control the welding speed to ensure that the temperature does not exceed the specified limit, and the other is to perform core extraction before welding.
During welding: It is generally required that the valve be in the open position; if it is closed, the soft seal may be damaged by heat, resulting in poor sealing and leakage! 2. The welding point of the bypass valve is too close to the circumferential weld; it is necessary for the distance from the weld to be greater than the heat-affected zone. 100 mm is generally used.
This type of welding is indeed quite difficult and requires a lot of experience
Welded valves are designed for welding anyway; anything you can think of has surely been taken into consideration during product design