The specialized cut-off valve for liquefied gas uses elastic formed polytetrafluoroethylene as the filling material. The sealing performance of the filling material increases with the increase of medium pressure and has the function of reverse sealing. It is widely used in urban liquefied gas and petroleum gas storage stations, as well as in liquefied gas systems in refineries and petrochemical plants, as an opening and closing device for controlling medium cut-off.
Structure description:
1. When the handwheel is turned clockwise, the valve stem moves downward and the valve disc descends, causing the sealing surface to close and cutting off the passage. When reversing, it opens, and the valve stem is sealed at the highest point to take effect.
2. Added an upper seal when the valve is open. Two layers of sealing effect are applied together with the packing, and it has a certain protective effect on the packing.
3. Using nylon products as the sealing surface, the filler is soft formed filler, and the upper seal is also made of soft material, with good sealing performance.
Working principle:
The liquefied gas dedicated shut-off valve uses formed polytetrafluoroethylene/flexible graphite as the sealing packing, and the initial sealing is provided by the packing gland. When dynamic sealing leakage occurs due to wear, the packing gland nut can be adjusted, which is suitable for most high and medium pressure non corrosive fluid transmission occasions. A groove is set on the metal sealing surface of the valve disc, and a soft sealing ring is embedded with the metal sealing surface of the valve seat to form a soft and hard dual sealing structure, improving sealing performance and avoiding static electricity caused by rotating friction of the metal seal. The metal hard sealing surface protects the soft sealing material from overload and damage, extending the service life of the valve. Suitable for industries such as petroleum, chemical, steel, hydraulic, and power. The valve seat sealing surface material is nylon plastic, the nominal pressure is PN40, and the valve body material is carbon steel.
Product features:
1. The sealing surface material of the valve seat is nylon plastic, which improves the sealing performance and avoids static electricity generated by metal seal rotation friction, causing sparks.
2. Anti static structure: When the inner sealing body of the valve rotates and rubs to generate static electricity, a conductive device is used to connect with the ground, thereby avoiding static electricity causing natural gas fires.
3. Fireproof structure: When the soft sealing material is burned out, the metal sealing surface can still remain sealed to avoid the expansion of the fire.
4. When the external part of the valve catches fire, the soft sealing material is burned out by high temperature, and its metal seal can still ensure the valve is tightly sealed, forming a dual sealing structure of soft and hard, with good sealing performance.
5. Using elastic V-shaped polytetrafluoroethylene or nitrile rubber as dynamic sealing filler, the initial sealing is provided by the filler cover and stainless steel spring. The sealing performance of the filler increases with the increase of medium pressure, which means it has self sealing performance and does not require manual maintenance.