Gate valve is the main component of oil (gas) wellhead equipment. The common faults of several gate valves in use are as follows:
1.Leakage at the joint of gate valve
First of all, To check whether the connecting bolts between valves are already tightened. If not, the gasket and the flange surface will be not fully combined, which will often lead to leakage. The bolts and nuts shall be checked in sequence and all bolts shall be tightened until the gasket pressed. Secondly, the size and accuracy of the sealing should be checked. If the size of the sealing surface is not correct or too rough, the sealing gasket should be repaired or renewed. In addition, To check whether there are corrosion, pin holes, sand holes or impurities in gasket or flange. If there are such defects, Repairing welding or cleaning should be carried out.
2. Leakage at bonnet
Bonnet leakage, This fault is mainly appeared in the packing or gasket sealing. First, To check whether the seal is correctly selected and matched with the sealing groove. If there is such a problem, replace the sealing ring or repair the sealing groove. Secondly, check whether the seal has burr, fracture, twist and other phenomena, in this case, the seal should be replaced. Again, check whether the sealing surface of each sealing groove is rough or has other defects. If there are defects, eliminate the defects or update the damaged parts.
There are packings to seal by compression in the valve cover &support, To check the installation of these packings. If it is found that the upper and lower packings are installed upside down, they should be removed and re installed according to the correct method. Special attention should be paid to the matching of the joint surface of the packing seal. Furthermore, check the accuracy of each contact surface of the seal meets the specified requirements.
3. Leakage at the surface of valve’s body
In the casting process of valve, Sometimes there are sand holes, sand holes and other casting defects, which are difficult to be found in the machining process. While the pressure is applied, the hidden casting defects will be exposed. In this case, it is necessary to repair welding, repair or update
Post time: Nov-17-2020