Cast Steel Soft Seated Flanged Ball Valve Q41F

Functional Application

Ball valves are mainly used for cutting off, distributing, and changing the direction of medium flow in pipelines. As a widely adopted modern valve type, it boasts the following advantages:

1. Minimal fluid resistance, its flow resistance coefficient is equal to that of an equal-length pipe section.

2. Simple structure, compact size, and light weight.

3. Tight and reliable sealing. A wide range of sealing materials are used, and it is also commonly applied in vacuum systems.

4. Easy operation and quick switching. Only a 90° rotation is needed from fully open to fully closed, making remote control convenient.

5. Simple maintenance. The ball valve structure is straightforward, and sealing rings are generally movable, allowing easy removal and replacement.

6. During full opening or closing, the sealing surfaces of the ball and valve seat are isolated from the medium. The medium will not cause erosion of the valve sealing surface.

7. Wide application range. Sizes range from a few millimeters to several meters, and it can be used from high vacuum to high pressure.

Ball valves are widely used in industries such as petroleum, chemical, power generation, papermaking, atomic energy, aerospace, and rocket engineering, as well as in daily life.

 Main Classification & Structural Forms

1. Floating Ball Valve

The ball body is floating. Under medium pressure, the ball will displace and press tightly against the outlet end sealing surface to ensure outlet-end sealing.

The floating ball valve features simple structure and reliable sealing. However, all medium load on the ball is transferred to the outlet sealing ring, so sealing ring material must withstand the working load of the medium.

This design is widely used for low and medium pressure valves.

2. Trunnion Mounted Ball Valve

The ball body is fixed and will not shift under pressure. This design is equipped with a floating valve seat. After medium pressure builds up, the valve seat moves to press the sealing ring firmly against the ball body for reliable sealing.

Usually, upper and lower shafts are installed between the ball and valve body, reducing operating torque. It is suitable for high pressure and large bore valves.

To reduce operating torque and enhance sealing reliability, oil injection ball valves have been developed in recent years. Special lubricant is injected between sealing surfaces to form an oil film, strengthening sealing while lowering operating force. Ideal for high pressure and large diameter applications.

3. Elastic Ball Valve

The ball body itself is elastic. Both the ball and valve seat sealing rings are made of metal, requiring extremely high sealing specific pressure. Medium pressure alone cannot achieve a sufficient seal, so external force must be applied.

This type is suitable for high temperature and high pressure working conditions.

An elastic groove is opened on the inner wall of the ball body to gain elasticity. When closing the channel, the wedge-shaped head of the valve stem presses the ball tightly against the valve seat for sealing. When rotating the ball, the wedge head is first released, and the ball restores its original shape. This creates a tiny gap between the ball and seat, reducing sealing surface friction and operating torque.

Port Body Classification

According to port arrangement, ball valves can be divided into straight-way, three-way and right-angle types. The latter two are used for medium distribution and flow direction switching.

Other Classifications

1. O-type vs V-type Ball Valve

- O-type Ball Valve: Adopts floating ball design. The ball body is precision cast with hardened surface treatment. Valve seat is reinforced with PTFE material. Port diameter matches pipe nominal diameter, delivering maximum flow capacity and minimal flow resistance. Zero leakage when closed, generally used as an on-off valve. Ideal for high-viscosity, fiber and granular medium applications.

- V-type Ball Valve: Features a V-shaped notch on the ball body, achieving proportional adjustment with approximate equal percentage flow characteristics.

2. Actuator Options

According to working requirements, pneumatic or electric actuators can be equipped to form pneumatic ball valves and electric ball valves.

- Pneumatic type: realizes proportional regulation with valve positioner

- Electric type: achieves precise control with electronic electric actuator or servo amplifier

3. Material Classification

Cast steel ball valves, 304 stainless steel ball valves, 316 stainless steel ball valves.

4. Pressure Rating Classification by Application

- High Pressure Ball Valve: Widely applied in petroleum, natural gas, hydraulic engineering and heavy machinery industries

- Low Pressure Ball Valve: Mainly used for water and other non-corrosive medium pipelines