Today, Dervos takes you to know which components of soft seal gate valve are prone to leakage and how to prevent and remedy it well.

1.Leakage at Gate Valve Connection

First, we should check whether the connecting bolts between gate valves are tightened, ensure that the sealing gasket ring in it is fully combined with the flange sealing groove surface. Secondly, if leakage has occurred, please do these in sequence: Check the bolt and nut, Compress the sealing gasket ring, Check the size and accuracy of the sealing gasket ring and flange sealing groove surface. We can conduct corresponding repair, welding or cleaning according to the situation.

2.Leakage at Bonnet

Bonnet leakage is usually caused by leakage of packing seals. First, we should check the seal selection. If the seal selection doesn’t match the seal groove, it will be easy to leak. It’s necessary to replace the seal ring or repair the seal groove. Secondly, we should check whether the seal has burr, fracturing, torsion and other problems. If so, please replace it in time. Thirdly, we should check whether the sealing surface of each sealing groove is rough or defective. If any, please eliminate the defects or replace the damaged parts. Finally, we should check the installation of the packing. If the packing is installed upside down, remove it and reinstall it in the correct way.

3.Leakage at the Cavity Surface of the Valve Body

If there are sand holes, slag holes and other defects in the valve body during the casting process, it’s difficult to be found before the pressure test. Once the pressure is applied, leakage will occur in these places. In case of such problems, please repair, weld or replace them.

4.Leakage at Valve Seat Gate

First, we should check the accuracy of the sealing surface. If it’s too rough, it needs to be removed and reground. Secondly, we should Check whether there are pitting corrosion, indentation, sand hole, crack and other defects on the sealing surface. If so, the valve seat should be reworked and repaired. Thirdly, we should check whether the vulcanization integrated wedge has cracks and other defects. Finally, check whether there are foreign matters at the opening position inside the valve body of the soft seal gate valve. If so, clean it up before installation.

5.Leakage Caused by Sundries

If foreign matters such as welding slag, iron filings and impurities enter into the valve body, the sealing surface can be easily damaged, which will affect the sealing performance of the valve. At the same time, the valve plate won’t be closed to the expected depth, resulting in leakage. In this case, the valve body should be removed and cleaned.

6.Leakage Caused by Improper Closing of Wedge