How to replace the flange gasket of gate valves, ball valves, butterfly valves and other valves?
The accessories of valves such as gate valves, ball valves and butterfly valves are often more prone to damage than the valves themselves, such as flange gaskets. So how to replace the damaged flange gasket? Replacing the flange gasket should follow the following four basic principles, prepare materials and tools, pay attention to the operation steps, and meet two technical requirements and five key points.
(1) Preparation
① Materials: grease, cotton yarn, leak detection liquid, sealing gasket.
② Tools: wrench, screwdriver.
(2) Operation steps
① Remove the flange connection bolts, disassemble the valve or remove the leaking end pipe section. Remove the old sealing gasket from the sealing surface.
② Select the appropriate gasket and apply a uniform layer of grease on both sides.
③ Place the sealing gasket between the sealing surfaces of the two flanges, align the centers of the two flanges and the bolt holes, insert the bolts, screw on the nuts, and tighten the nuts evenly in multiple steps diagonally. The bolts should extend 2-3 thread pitches out of the nuts. After the flange gasket is installed, it should be tested at working pressure without leakage to be qualified.
(3) Technical requirements
① Be careful during operation to prevent damage to the flange plate.
② After completion, clean and maintain the tools.
(4) Five key points for gasket installation
① Choose correctly: The form, material and size of the flange, bolts and gaskets should be selected appropriately according to the operating conditions and the structure of the flange surface.
② Check carefully: Before installation, carefully check the quality of the flange, bolts, nuts and gaskets, and there should be no burrs, unevenness, cracks and other defects. Carefully check the installation of the flange and pipe, and there should be no misalignment, misalignment or misalignment of holes.
③ Clean thoroughly: The flange sealing surface must be cleaned thoroughly, and the bolts and gaskets should not be contaminated with impurities or oil stains.
④ Install correctly: The gasket should be concentric with the pipe or pipe fitting.
⑤ Tighten evenly: When installing bolts and nuts, apply force evenly and tighten them symmetrically in multiple steps.