Abstract: aiming at the defects of technology in the field of thermal insulation ball valve door, the seal material and seal structure was improved, make its can ensure the sealing performance under high temperature condition, and greatly improve its service life.
Key words: thermal insulation ball valve door;
Temperature with the continuous development of domestic industry, the demand for used on pipeline insulation ball valve door also will increase, more and more is also high to the requirement of insulation ball valve door, and a user choose insulation ball valve door, did pay special attention to the valve has good sealing performance to prevent the leakage of the medium.
Due to the reliability of the imported insulation ball valve door is better, so the user of the more important parts of the imported thermal insulation ball valve door, but the import insulation ball valve door is expensive, delivery cycle is long, after-sales service is not convenient, seriously affect the operation of the whole pipeline.
In order to reduce the cost of pipeline insulation ball valve door, realize localization, domestic manufacturer also unceasingly in the domestic insulation ball valve, sealing reliability, keep improving the quality of the door, to replace the imported thermal insulation ball valve gate.
In this paper, aiming at insulation ball valve door on the question of high temperature resistant were analyzed and improvement measures are put forward.
1 question existing technology in the field of thermal insulation ball valve door also called jacket ball valve door, is on the basis of the ball valve door welding metal jacket, jacket and the valve body between thermal channel, channel and injecting steam or other heat medium, to ensure that the valve works in media.
Insulation ball valve door has good insulation properties, and the same as that of the valve door size and, at the same time can effectively reduce the pipeline heat loss in the media.
Is mainly used in petroleum, chemical, metallurgical, pharmaceutical, food and other kinds of systems, in order to transport under normal temperature solidification of high viscosity medium.
Due to the valve door sealing structure and its corresponding sealing material, its use is less than the temperature of 200 ℃.
And for a long time at 200 ℃ under the condition of use, live shorter lives.
Although the valve seat can choose short time ability 300 ℃ high strength graphite materials, but there are many need to seal the valve gate area is still unable to seal in high temperature situation, especially in the radial sealing, high strength graphite materials not suitable for radial seal.
Insulation ball valve gates to seal is usually USES the o-ring seal structure, the use of the valve door temperature directly restricted by o-ring used temperature, the thermal insulation ball valve door use o-ring is fluorine rubber, and the use of fluorine rubber temperature within 200 ℃, and cannot be used within the limit temperature for a long time.
Far cannot satisfy the requirement of market in many media, such as the working medium of rosin, the requirement for insulation ball valve door use temperature of 300 ℃, such ability is helpful for medium to obtain ideal liquid rosin, using o-ring as traditional sealing parts, will not be able to meet their requirements.
2 improvement measures according to the problems existing in the insulation ball valve door, determine the insulation ball valve door sealing material and structure was improved.
In a sealed cavity with high temperature resistant material of flexible graphite seal ring, at the back of the sealing ring with a taper section of the gasket, washer fitted behind the special structure of the screw, so by tightening the plug, plug will be passed to the gasket, washer cone section will squeeze the sealing ring, sealing ring deformation, make its tiejin, both inside and outside the radial bearing ring and valve body, so that insulation ball valve door in radial sealing structure of high temperature resistant, at the same time, by tightening the screw, produce pre tight seal between the sphere and valve seat, make its seal.
On the valve seat sealing structure also makes the corresponding improvement, the insert structure, the valve body and supporting ring grooves dug up, groove bottom in sealed superior performance and high temperature resistance of the flexible graphite, can play a role at the bottom of the valve seat seal, and can play between the sealing deputy for heat bilges cold shrink compensation effect.
In flexible graphite is mounted on the high temperature resistant metal valve seat, use long time use within temperature to 425 ℃ can be improved, so as to solve the insulation ball valve door cannot be used at 200 ℃ or more long time.
And it also could be selected according to the requirement of the actual working condition of different material of the valve seat.
Discharge in figure 1, the function of the bottom of the pipe and plug is threaded connection, when the temperature rises, the threaded portion of seal is hard to guarantee, decided to cancel the plug, in figure 2 plug, which is connected with the bottom over changed into terraced drain plug and end connection with winding gasket seal, to ensure that the seal at the bottom of the reliability.
3 conclusion by improving insulation ball valve door seal structure, good sealing performance, especially the improved flexible graphite instead of the o-ring, the temperature & le;
Is widely used on the working condition of 425 ℃.
With the development of domestic industrial level and technological progress, its performance will continue to improve, application scope will continue to expand.
Insulation ball valve door is according to the market demand and improve the design and manufacture, the gate valve has a compact structure, convenient operation, reliable sealing and long service life etc, at present the insulation ball valve door in the user running in good working condition, various performance indexes meet the design requirements.
For easy setting, high viscosity liquid medium with excellent performance, especially suitable for thick mass media such as rosin.