How to deal with the leakage of weld neck flanges correctly?

　　The weld neck flange sealing treatment measures should be appropriate. According to previous experience, when the weld neck flange leakage problem is encountered, it is necessary to take into account the leakage location and condition of the weld neck flange bolts on both sides of the valve body of the DN150 body. Because the gap is very small, it is impossible to inject the sealant through the gap to eliminate the leakage. The leakage medium is steam, the leakage system temperature is 400~500 degrees, and the system pressure is 4MPA. Therefore, it is impossible to eliminate leakage by sealing the DIN 2527 PN16 Stainless Steel Weld Neck Flange.

　　Common sealing methods are:

　　Firstly, fixture design (1) fixture structure form to determine the containment leakage point, the establishment of valve body weld neck flange and pipe flange connection between the short flange sealing chamber. In order to prevent the potential leakage between the valve body and the weld neck flange from leaking again due to the compression, a circular cavity is set up to inject glue at the joint of the clamp and the weld neck flange outer edge of the valve body. (2) In the process of injection of different diameter weld neck flange, the clamp is apt to displace to the side of small diameter flange, so the limit measure of tooth-shaped contact clamping is adopted.

　　Secondly, sealant selection and dosage estimation (1) Sealant selection according to the leakage system temperature and leakage site characteristics, using TXY-18 A type sealant. The sealant has excellent heat resistance, medium resistance and injection process performance, is easy to establish a uniform and compact sealing structure, and the sealing can maintain long-term stability. (2) the use of sealant 4.5KG should be used for unilateral leakage.