ANSI Bellows Gate Valve

Bellows gate valve is a type of valve widely used in industrial piping systems. The following is a brief introduction to it:

Definition and Principle

• Definition: Bellows gate valve refers to a valve that uses a bellows as a sealing element and a gate as the main component to cut off the medium.

• Principle: It relies on the lifting of the gate to open and close the valve, thereby controlling the flow and cut-off of the medium in the pipeline. When the gate descends and fits with the seat sealing surface, the valve closes to prevent the medium from passing through. When the gate rises and leaves the seat sealing surface, the valve opens to allow the medium to flow. During the movement of the valve stem, the bellows expands and contracts accordingly, forming a sealing barrier to prevent the medium from leaking out along the valve stem.

Structural Features

• Bellows Sealing: A metal bellows is used as the main sealing element to effectively isolate the medium from the external environment and achieve zero leakage. It is especially suitable for pipeline systems with toxic, harmful, flammable and explosive media.

• Dual Sealing Guarantee: It is usually equipped with packing sealing as an auxiliary seal to form a dual sealing structure with the bellows. When the bellows is accidentally damaged, the packing seal can serve as a second line of defense to further ensure the sealing performance and improve the reliability and safety of the valve.

• Gate and Seat: The sealing surfaces of the gate and seat are usually specially treated, such as hard alloy surfacing, which have good wear resistance, corrosion resistance and anti-scuffing performance, ensuring long-term and stable sealing effect.

• Valve Stem Design: The valve stem is generally made of high-quality materials and treated by quenching and tempering, surface nitriding, etc. It has high strength and hardness, and also has good corrosion resistance and anti-friction performance, ensuring that the valve stem can work properly during frequent lifting movements.

Performance Advantages

• Excellent Sealing Performance: The sealing function of the bellows can effectively prevent the leakage of the medium. Especially in occasions where strict requirements are imposed on tiny leakage, it can meet extremely high sealing standards.

• Strong Corrosion Resistance: The bellows and other key components are made of corrosion-resistant materials, enabling it to work stably in various corrosive media and prolonging the service life of the valve.

• Wide Application Range: It can be applied to a variety of media, including water, steam, oil products, various corrosive chemical media, etc., and can work within a wide temperature and pressure range. Generally, the pressure range can reach PN1.0 - 16.0MPa or even higher, and the temperature range is about -29°C - 500°C, depending on the material selection.

• Flexible and Light Operation: The operating torque of the valve is relatively small. Whether it is manual, electric or pneumatic operation, the opening and closing of the valve can be easily realized, reducing the labor intensity of operators and facilitating automatic control.

Application Fields

• Petrochemical Industry: In the process of petroleum refining and chemical production, it is used in pipeline systems for transporting various petroleum products, chemical raw materials and other media, such as crude oil transportation, inlets and outlets of chemical material reaction kettles, etc.

• Power Industry: In power facilities such as thermal power plants and nuclear power plants, it is used in pipelines for steam, water and other media, such as main steam pipelines and condensate water pipelines, to ensure the safe and stable operation of the power system.

• Pharmaceutical Industry: In the pharmaceutical process, it is used in the pipelines for transporting various drug raw materials, intermediates and finished products, meeting the strict requirements of the pharmaceutical process for the purity and tightness of the medium and preventing drug contamination and leakage.

• Other Fields: It is also widely used in natural gas transportation, metallurgy, papermaking, food and beverage and other industries to control the flow of various fluid media.