News
15
2021
-
09
Advantages and Classification of Blowdown Ball Valves
Author:
Ball valve and plug valve belong to the same type of valve. Only its closing part is a sphere, which rotates around the center line of the valve body to open and close. The blowdown ball valve is mainly used to cut off, distribute and change the flow direction of the medium in the pipeline. Blowdown ball valve is a new type of valve widely used in recent years, which has the following advantages:
1. The fluid resistance is small, and its resistance coefficient is equal to the pipe section of the same length.
2. Simple structure, small volume and light weight.
3. Tight and reliable. At present, plastic is widely used as the sealing surface material of the blowdown ball valve, which has good sealing performance and is widely used in the vacuum system.
4. It is easy to operate and fast to open and close. Only 90 rotations are required from full opening to full closing, which is convenient for remote control.
5. The ball valve is easy to maintain and has a simple structure. It is generally a movable seal ring, which is easy to remove and replace.
6. When the valve is fully opened or closed, the sealing surfaces of the ball and valve seat are isolated from the medium. When the medium passes through, it will not cause corrosion of the valve sealing surface.
7. It has a wide range of applications, ranging from a few millimeters to several meters in diameter, from high vacuum to high pressure.
Blowdown ball valves have been widely used in petroleum, chemical industry, power generation, paper making, atomic energy, aviation, rocket and other sectors, as well as in people's daily life.
The blowdown ball valve can be divided into:
1. Float
The sphere is floating. Under the action of medium pressure, it can produce a certain displacement and press tightly on the sealing surface of the outlet end to ensure the outlet end sealing. It has simple structure and good sealing performance, but the load of the working medium borne by it is all transferred to the outlet sealing ring. Therefore, it is necessary to consider whether the sealing ring material can bear the working load of the spherical medium. This structure is widely used in medium and low pressure ball valves.
2. Fixed
The ball of the ball valve is fixed and will not move under pressure. Both are equipped with floating valve seats, which move under the pressure of the medium to make the sealing ring tightly press on the ball to ensure sealing. Generally, bearings are installed on the upper and lower shafts of the ball. The operating torque is small, and it is suitable for high-pressure large caliber valves.
In order to reduce the working torque and increase the reliability of sealing, oil sealed ball valves have emerged in recent years. They not only inject special lubricating oil between the sealing surfaces to form an oil film, but also enhance the sealing performance, reduce the working torque, and are more suitable for high-pressure large caliber ball valves.
3. Elasticity
The sealing ring of the valve seat and the ball valve seat are made of metal materials, so the sealing specific pressure is very high. The pressure of the medium itself cannot meet the sealing requirements, so external force must be applied. The blowdown ball valve is applicable to high temperature and high pressure medium.
The elasticity is realized by opening an elastic groove at the lower end of the inner wall of the sphere. When the channel is closed, the wedge head of the valve stem is used to expand the ball and press the valve seat to achieve sealing. Before turning, loosen the wedge head to restore the original state and make a small gap with the valve seat, which can reduce the friction of the sealing surface and reduce the operating torque.
Hot News
Precautions for using blowdown ball valve?
2021-09-15
Main： Butterfly valves, blind valves, gate valves, globe valves, ball valves, check valves, regulating valves, gates, metallurgical valves, hydraulic dams
Contact Us
Address: north of Longjiang Road, west of Jinping Road, Shangdi District, Zhengzhou City
Copyright © Henan Yuzhou Fluid Technology Co., Ltd. All rights reserved
Supported IPV6