It is not suitable for nuclear working conditions, lye or fluoride applications. It cannot be used in strong oxidants such as oxygen, nor is it suitable In the case of concentrated sulfuric acid and nitric acid, otherwise the packing will break easily and cause leakage.1 background During the on-site use of the regulating valve, due to various reasons such as the environment, working conditions and the structure of the valve body, the packing of the regulating valve leaks. Because graphite is easy to adsorb gas or water molecules, it forms a layer on its surface Very thin air or water film to prevent the penetration of process media.
PTFE Polytetrafluoroethylene is a synthetic resin material with stable physical and chemical properties, good resistance to chemical corrosion, and an excellent sealing material with good anti-aging properties, good sealing performance, and low friction coefficient. When the BBQ grill mat Manufacturers upper and lower limits of temperature change greatly, its sealing performance will be significantly reduced; at the same time under pressure , It is easily deformed by heat and affects the sealing performance.. Commonly used fillers can be divided into two categories according to their materials: graphite and polytetrafluoroethylene. Its surface friction is small and its self-lubricity is very good. Its physical properties determine its softness and elasticity. The main chemical composition of graphite is carbon, which has stable chemical properties, corrosion resistance, high and low temperature resistance, but the graphite packing has a large hysteresis, and the valve stem will crawl during initial use.
Graphite It is made of natural graphite and is an ideal sealing material. It is not uncommon to see cases of device shutdown caused by the leakage of the control valve packing. This is a relatively common fault of the regulating valve and a key factor affecting the continuous production of system devices. Due to the fact that there are many reasons for the problem, the analysis of the problem Before the elimination, a brief introduction to the regulating valve packing is as follows: The packing of the regulating valve is generally installed in the stuffing box of the upper bonnet of the regulating valve, and its function is to prevent the leakage of the regulated process medium due to the movement of the valve stem.
How to solve the control valve packing leakage has become the key task of the instrument workers’ daily inspection and maintenance. Many kinds of fillers are derived from these two types of substrates to meet the requirements of different working conditions. , Is an ideal sealing material under normal circumstances; the disadvantage is that the working temperature of PTFE is within the range of -40℃～+232℃.
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