The threaded ball valves with internal threads are mainly divided into one-piece ball valves, two-piece ball valves and three piece ball valves according to their structures. Understanding their characteristics and differences will help us to select appropriate ball valves for use.
First of all, we should know what is one piece ball valve, two piece ball valve and three piece ball valve by definition.
One piece ball valve refers to the ball valve connected by small diameter internal thread and composed of an integral one-piece valve body. The integral valve body is commonly used for small size valves.
The two-piece ball valve, also called two-piece ball valve, refers to the valve connected by small caliber internal thread. The valve body is divided into two parts, in the form of a butt joint. It is usually used.
Three piece ball valve is connected by internal thread. The valve body is composed of three parts. It is usually used for larger and more important valves.
The One-piece ball valve has reduced diameter. The sphere is fixed by a plug head and the flow is relatively small.
The two-piece ball valve has full diameter. It is fixed by two pieces of valve body clamped ball body. The maintenance is relatively complex. The middle of the screw tightness is the key to deciding whether there is air leakage or not. The sealing is relatively good.
The three-piece ball valve is similar to the two-piece ball valve. It also has a full diameter. However, there is a valve body in the middle of the ball, and then clamped by both sides with the neck flange. The bearing pressure is better. The installation is convenient. The disassembly, maintenance and cleaning are very easy.
The brief introduction of one-piece ball valves
One-piece stainless steel ball valves belong to the type of manual valves. The ball valve is a ball with a circular channel as the opening and closing parts. The ball rotates with the stem to realize the opening and closing action of the valve. The opening and closing part of the ball valve is a perforated sphere that rotates around the axis perpendicular to the channel. It also to achieve the purpose of opening and closing the channel. The ball valve is mainly used to cut off or connect the pipeline and equipment medium and fluid regulation and control. The fluid resistance of ball valves is small. The structure is simple. The volume is small. The weight is light, and it is close and reliable. It is easy to operate and maintain. It will not cause the erosion of the sealing surface of the valve. The range of applications is wide.
Technical parameters of one-piece ball valves:
1. Nominal pressure: 1.6-6.4MPa
2. Applicable stable range: -20 ~ 232℃ ~ 350℃
3. Applicable medium: water, oil, gas and some corrosive liquids (W. O. G)
4. Thread types: G, NPT, BSPT, BSP, DI259/2999
Silica sol cast stainless steel valve body, valve cover
Thread types: NPT, BSPT, BSP, DIN259/2999
One-piece ball valves with internal thread cannot be made into a high platform.
It can not be matched with electric, pneumatic and other actuators
Performance specifications of two-piece ball valves:
Operating pressure: 1000PSI PN64
Operating temperature: -20 ~ 232℃
Applicable medium: water, oil, gas or other corrosive liquids
Thread standards: NPT, BSPT, BSP, DIN259/2999
Features of three-piece ball valves
The three-piece ball valve is a relatively new category of ball valves. By using foreign advanced technology, the structure of the valve body cast is reasonable with a beautiful shape. The seat of three-piece ball valves adopts elastic sealing structure. The sealing is reliable, and it is easy to open and close. The valve stem adopts a downward sealing structure. The valve chamber abnormal pressure boost, and the valve stem will not be rushed out. It is widely used in petroleum, chemical industry, urban water supply and drainage strictly cut off conditions.
Applications of three-piece ball valves
The three-piece ball valve is suitable for air, steam, water, gas, petroleum and petrochemical products, corrosive media, which is widely used in petroleum, chemical, metallurgy, light industry, paper-making, power station, refrigeration and other work fields. The products of three-piece flanged ball valves have a compact structure, beautiful appearance and intelligent control. It is easy to use and has many other characteristics. As for manual operation angle of 90° rotary ball valves, the sealing performance is excellent. The flow capacity and flow resistance coefficient are small. The structure and maintenance are simple. The service life is long. The one-piece ball valve is usually used in strict sealing requirements in the control of gas, liquid, steam medium. It is also suitable for the control of sewage and containing fibrous impurities of the medium.