Gate valve packing leakage
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The packing of the gate valve connecting the storage tank is leaking, causing a large amount of fluid from the tank to leak out through the packing. How should the packing be replaced in this situation? Should the valve be closed or fully opened? How to replace the packing? Please ask an expert to explain, thank you, bonus points
Operating under pressure is very dangerous; empty the contents of the tank before replacing it
This post was last edited by hlcl on 2016-8-15 at 16:35. Each valve is equipped with an upper seal, which helps to reduce leakage or even eliminate it when the valve is fully open; it can also be replaced while the system is in operation. Use a respirator when dealing with toxic substances, and use explosion-proof tools when working with flammable substances. It is recommended to add a few more sections of packing; completely replacing it still carries a high risk. Graphite packing is preferred.
It is necessary to check the liquid level in the storage tank; if the level is low, the valve can be closed and the component replaced directly, or one or two more graphite rings can be added to tighten it. If the liquid level is high, graphite packing rings can be added during discharge and tightened.
Theoretically, when a gate valve is fully closed, aside from the medium present beneath the valve cover, no medium will enter the packing area either in front of or behind the valve.
Theoretically, whether it is a rigid gate or an elastic gate, forced sealing is achieved at the outlet end; therefore, the valve chamber is under pressure. Adding packing when closing the valve will definitely cause problems. According to the rules, the filler is added after pressure release. If it is a non-toxic, non-polluting medium at low pressure, such as water, the upper seal can be fully opened and packing can be added after it takes effect; however, standards explicitly prohibit such a method of operation
The packing is used to press down the valve stem to prevent leakage; it is not possible to carry out maintenance under pressure with material present if the packing is not removed completely
If the valve stem is designed to prevent backflow, can it be replaced while the system is under pressure? What is contained in the tank? The pressure should not be high.
I was just wondering why no secondary line was added when this pipeline was designed? What a trivial mistake this must be. The main pipeline should be designed with a check valve plus a gate valve installed in front of the pump’s outlet, and a discharge/vent valve should be placed between the check valve and the gate valve. The auxiliary pipeline should run from in front of the main pipeline’s check valve all the way to behind its gate valve; only one gate valve is needed on this auxiliary pipeline, so as to facilitate maintenance in case of problems, and to avoid having to stop operations due to such minor issues, which could affect production and storage processes.