Compared with other types of valves, pneumatic ball valves have the advantages of angular stroke output torque, rapid opening, stability and reliability, wide application, and the following:
1. The thrust bearing reduces the friction torque of the valve stem, which can make the valve stem operate stably and flexibly for a long time;
2. Anti static function: spring is set between the ball, valve stem and valve body, which can lead out the static electricity generated in the process of switching;
3. Because materials such as polytetrafluoroethylene have good self-lubricating property and small friction loss with the ball, the service life of pneumatic ball valve is long;
4. Low fluid resistance: pneumatic ball valve is the one with low fluid resistance in all valve categories. Even for reduced diameter pneumatic ball valve, its fluid resistance is relatively small;
5. Reliable valve stem sealing: because the valve stem only rotates rather than rises and falls, the packing seal of the valve stem is not easy to be damaged, and the sealing capacity increases with the increase of medium pressure;
6. Good sealing performance of valve seat: the sealing ring made of elastic materials such as polytetrafluoroethylene is easy to seal, and the sealing capacity of pneumatic ball valve increases with the increase of medium pressure;
7. The fluid resistance is small, and the full bore ball valve basically has no flow resistance;
8. Simple structure, small volume and light weight;
9. Tight and reliable. It has two sealing surfaces, and the sealing surface material of the ball valve is widely made of plastic, with good sealing performance and complete sealing. It has also been widely used in vacuum systems;
10. Convenient operation, fast opening and closing, 90 ° rotation from full opening to full closing, convenient for remote control;
11. Convenient maintenance, simple structure of ball valve, generally movable sealing ring, convenient disassembly and replacement;
12. When the valve is fully opened or closed, the sealing surface of the ball and the valve seat is isolated from the medium. When the medium passes through, the sealing surface of the valve will be eroded;
13. Wide range of applications, ranging from a few millimeters to several meters in diameter, from high vacuum to high pressure;
14. The ball valve can be used in media with suspended solid particles due to its wiping property during opening and closing;
15. High processing precision, high cost, and unsuitable for use in high temperature. If there are impurities in the pipeline, it is easy to be blocked by impurities, resulting in the valve can not be opened.
The ball valve in the pipeline is mainly used to cut off, distribute and change the flow direction of the medium. It can be closed tightly with only 90 degree rotation and a small rotating torque. The ball valve is suitable for use as a switch and cut-off valve, V-type ball valve. In addition to the pipeline parameters, special attention should be paid to the environmental conditions for the use of electric valves. Since the electric device in the electric valve is an electromechanical device, its use status is greatly affected by its use environment. In general, special attention should be paid to the use of electric ball valves and butterfly valves in the following environments.
Our company is located in the county known as the hometown of Chinese valves. It is an enterprise producing various stainless steel and forged steel valves, with a history of producing valves for many years. Covering an area of 9860 square meters, it has a modern fully enclosed workshop and various processing and testing equipment. It is a modern enterprise integrating R&D, manufacturing, sales and services, and produces various gate valves, stop valves, ball valves, check valves, plug valves, hard seal butterfly valves, instrument valves, pipe fittings and other products. Its main products include: high pressure ball valves (gas high pressure ball valves, CNG high pressure ball valves, LNG high pressure ball valves), high temperature and high pressure stop valves, gas safety valves, emergency pull off valves (CNG emergency pull off valves LNG emergency pull off valve), high pressure check valve, pressure stop valve, imitation imported instrument valve, high-pressure connector of gas station, etc., and undertake the design, processing and production of various non-standard products. The products are widely used in petroleum, chemical industry, metallurgy, electric power, pharmacy, paper making, food, energy and other industries. After years of development and progress, our products have won the trust of users all over the country and abroad.
Our factory strictly implements the procedures and requirements of ISO9001 international quality system certification, always adheres to the concept of "low profit, benefit", follows the service tenet of "quality, customer first", constantly improves product quality and service, establishes and improves service outlets, and provides customers with more products and services!
What are the new structural forms of ball valves and their advantages.
In recent years, some new structures of ball valves have appeared, and some measures have been taken to solve the problems of large opening and closing torque of ball valves and the application of external force on the sealing pressure of the sealing pair of the opening and closing parts. The structural forms are as follows:
① Pre press seal (using soft material valve seat such as polytetrafluoroethylene, pre press the spherical surface during installation to form a seal);
② Elastic translational sealing (the elastic valve seat or elastic element is used to push the valve seat to move parallel to the spherical surface and close to the spherical surface to form a seal);
③ The ball swings and presses the seal (for example, the rail ball valve uses the steering joint or chain at the lower end of the ball or the ball flap as the fulcrum, and uses the cam mechanism or pull up disc on the valve stem to tilt and swing the ball or the ball flap to the valve seat at a certain angle to press the valve seat and form a seal);
④ The inclined plane opens the ball disc and pushes the high-temperature and high-pressure ball valve butterfly valve with compression seal in parallel, that is, the wedge ball with an inclined plane in the middle of the combined ball moves downward, opens the ball disc with the wedge ball as the inclined plane, moves parallel to the two valve seats, presses the valve seat and forms a seal);
⑤ The rolling ball valve is sealed.
When the ball or combined sealing surface in the ball valve cavity rotates to the position corresponding to the sealing surface of the valve seat, there is still a gap between the sealing surfaces. The ball or combined ball disc rolls a distance towards the valve seat along the central axis of the valve seat, driven by the external force transmitted by the valve stem on the push pull rotary device, like a ball rolling on the platform, and pressing the valve seat to form a seal, and the valve closes. On the contrary, the ball or combined ball disc is pulled to the center of the valve chamber along the central axis of the valve seat and rolled back to the original position, forming a gap between the sealing surfaces, and the pressure of the inlet and outlet media is in balance. When the ball or combination ball is rotated to the open position, the ball valve will open.
These new structures have solved the problems of friction between the ball and the valve seat during the opening and closing process of traditional ball valves to varying degrees, such as large opening and closing torque, time-consuming and laborious operation, large energy consumption, and short service life of the sealing pair. However, if the ball valves with these structures are used in aerospace cryogenic systems, they can basically not meet the internal and external sealing requirements at liquid hydrogen temperature, Since these structures are deformed at low temperature, no corresponding adjustment mechanical force is applied to meet the requirements of sealing specific pressure. It can also not solve the leakage problem caused by traditional packing seal at low temperature. These shells can only be of upper and lower combined structure, which is not conducive to the design requirements of vacuum insulation jacket for ball valves. In order to meet the strict internal and external sealing requirements of hydrogen, a new structural design of pneumatic vacuum insulated cryogenic ball valve was proposed by studying the key technologies of cryogenic ball valve.
Features of floating ball valve:
The main advantages of floating ball valve are simple structure, convenient manufacturing, low cost and reliable work, so it is widely used. The sealing performance of the floating ball valve is related to the fluid pressure. Under the same other conditions, generally speaking, the higher the pressure, the easier it is to seal, and vice versa. However, it should be considered whether the valve seat material can withstand the load transmitted to it by the injection ball, because the force generated by the fluid pressure on the ball will be transmitted to the rear valve seat. In addition, for larger floating ball valves, when the pressure is high. The operating torque and the white weight of the sphere are also large.
Features and advantages of fixed ball valve:
1. Double blocking and discharging function: the fixed ball valve uses the spring to pre tighten the floating valve seat. No matter the valve is in the fully open or fully closed state, the valve seats at the upstream and downstream sides block the fluid, and the residues in the valve body cavity are discharged through the discharge valve.
2. Automatic pressure relief function: in case of abnormal pressure rise caused by the temperature rise of the medium staying in the valve body cavity, it is not necessary to pass through the valve, but only the valve seat function can automatically relieve pressure, which is very important for the valve to transport liquid medium.
3. Fire protection structure: all valves have fire protection function
Instructions for installation and use of ball valve:
1. The front and rear pipelines of the ball valve have been prepared. The front and rear pipes shall be coaxial, and the sealing surfaces of the two flanges shall be parallel. The pipeline shall be able to bear the weight of the ball valve, otherwise the pipeline shall be equipped with proper support.
2. Purge the pipeline before and after the valve to remove oil, welding slag and all other impurities in the pipeline.
3. Check the mark of the ball valve and make sure the ball valve is intact. Fully open and close the valve several times to verify its normal operation.
4. Remove the protective parts on the connecting flanges at both ends of the ball valve.
5. Check the valve hole for possible dirt, and then clean the valve hole. Even if there are only small particles between the valve seat and the ball, the sealing surface of the valve seat may be damaged.
6. Install the valve into the pipeline. One end of the valve can be installed on the upstream end. The valve driven by the handle can be installed on the pipeline. However, the ball valve with gear box or pneumatic driver shall be installed vertically, that is, installed on the horizontal pipeline, and the driving device is above the pipeline.
7. The sealing gasket shall be installed between the valve flange and the pipeline flange according to the pipeline design requirements.
8. The bolts on the flange shall be tightened symmetrically, step by step and evenly.
9. Connect the pneumatic pipeline.
10. Operate the driver to open and close the ball valve for several times, which should be flexible without stagnation, and verify that it works normally.
11. Check the sealing performance of the flange joint surface between the pipeline and the ball valve according to the pipeline design requirements.
