Electric Metal-Seated Ball Valve Q947Y

Practical Function

Ball valves are mainly used for shut-off, distribution and changing the flow direction of media in piping systems. As a new type of valve widely adopted in recent years, ball valves feature the following advantages:

1. Low fluid resistance, its resistance coefficient is equivalent to that of a pipe of the same length.

2. Simple structure, compact size and light weight.

3. Reliable sealing. Plastic materials are widely used for the valve sealing surfaces with excellent sealing performance, and they are also extensively applied in vacuum systems.

4. Easy operation and rapid opening/closing. Only a 90° rotation is required from fully open to fully closed position, which facilitates remote control.

5. Convenient maintenance. The ball valve features a simple structure, and the sealing rings are generally movable, making disassembly and replacement easy.

6. When fully open or closed, the sealing surfaces of the ball and valve seat are isolated from the medium. No erosion will occur on the valve sealing surfaces when the medium passes through.

7. Wide application range. Sizes range from a few millimeters to several meters in diameter, and it can work under conditions from high vacuum to ultra-high pressure.

At present, ball valves are widely applied in industries including petroleum, chemical engineering, power generation, papermaking, atomic energy, aerospace, rocket manufacturing, as well as daily life scenarios.

 Main Classification

By Structural Form

1. Floating Ball Valve

The ball body of the floating ball valve is unconstrained. Under the pressure of the working medium, the ball body generates displacement and presses tightly against the sealing surface at the outlet end, ensuring tight sealing at the outlet.

The floating ball valve boasts a simple structure and excellent sealing performance. However, the full medium pressure load borne by the ball body is entirely transmitted to the outlet sealing ring. Therefore, it is necessary to verify whether the sealing material can withstand the working load pressure from the process medium. This structure is widely used for low and medium pressure working conditions.

2. Trunnion (Fixed) Ball Valve

The ball body of this valve is fixed and will not shift under pressure. All fixed ball valves are equipped with floating valve seats. When subjected to medium pressure, the valve seat moves axially, pressing the sealing ring firmly against the ball body to achieve reliable sealing. Usually, upper and lower support trunnion shafts are installed on the ball body, which greatly reduces operating torque, making this valve suitable for high-pressure and large-caliber applications.

To reduce operating torque and improve sealing reliability, oil-sealed ball valves have been developed in recent years. Special lubricating grease is injected between the sealing surfaces to form an oil film, which not only enhances sealing performance, but also further reduces operating torque, making it ideal for extra-large diameter ball valves.

3. Elastic Ball Valve

The ball body of an elastic ball valve has built-in elasticity. Both the ball body and valve seat sealing ring are manufactured from metallic materials, requiring extremely high specific sealing pressure. Reliable sealing cannot be achieved only by the medium's own pressure, so additional external compressive force must be applied. This type of valve is suitable for high temperature and high pressure service.

An elastic compliant groove is machined at the lower end of the ball body to provide elastic preload. When closing the valve passage, the wedge-shaped head of the valve stem pushes the ball body tightly against the valve seat to form a tight seal. When rotating the ball to open the valve, the ball rebounds slightly to its original geometry, creating a tiny clearance between the ball and valve seat, thus effectively reducing friction on the sealing surface and required operating torque.

By Port Configuration

Ball valves are categorized by flow passage layout into straight-way type, three-way type and right-angle type. The latter two designs are used to distribute medium and alter fluid flow direction.

Other Classifications

Ball valves are available in O-type ball valves and V-type ball valves.

- O-type ball valve: Adopts floating ball construction. The ball body is precision cast with hardened surface treatment. The valve seat is made of reinforced PTFE material. Its flow bore matches the nominal pipe diameter, delivering extremely high flow capacity and minimal flow resistance. It achieves zero leakage when closed, and is generally used as an on-off valve. It is especially ideal for high-viscosity, fibrous and granular media.

- V-type ball valve: Features fixed trunnion ball design. A precision V-cut notch is machined on the ball body to realize proportional regulating function, with flow characteristics approximating equal percentage performance.

According to different process requirements, pneumatic or electric actuators can be selected, forming pneumatic ball valves and electric ball valves respectively.

- For proportional regulation of pneumatic ball valves: A valve positioner is required for installation.

- For proportional regulation of electric ball valves: An electronic electric actuator or servo amplifier must be equipped.

By material: Carbon steel ball valves, 304 stainless steel ball valves, 316 stainless steel ball valves and bronze ball valves.

By application pressure grade: High-pressure ball valves and low-pressure ball valves.

- High-pressure ball valves: Mainly applied in petroleum, natural gas, hydraulic system, engineering machinery and other heavy industrial sectors.

- Low-pressure ball valves: Primarily deployed in non-corrosive medium pipelines such as water service systems.