In the fluid control systems of industrial production, the performance of Control Valves is directly related to the stability, safety, and economy of production. The pneumatic bellows control valve, as an advanced device integrating pneumatic drive and bellows sealing technology, occupies an important position in many industrial fields with its unique design and excellent performance. The pneumatic bellows control valve is mainly composed of a pneumatic actuator, a bellows sealing assembly, a valve body, a valve stem, and a valve core. Among them, the bellows sealing assembly is its core feature, usually made of corrosion-resistant materials such as stainless steel. One end of the corrugated bellows is tightly connected to the valve stem, and the other end is fixed on the valve body, forming a completely sealed space. This can effectively prevent the medium from leaking out along the valve stem, making it show significant advantages when dealing with toxic, harmful, flammable, explosive, or high-purity media. The pneumatic actuator provides power for the action of the valve. It receives the air pressure signal from the controller and converts it into mechanical force to drive the valve stem and valve core to reciprocate, thereby changing the flow area between the valve core and the valve seat, and realizing precise control of fluid flow, pressure, temperature, and other parameters.
Its working principle is based on the transmission and conversion of pneumatic signals. When the control system sends a regulating signal, the air pressure signal enters the membrane chamber or cylinder of the pneumatic actuator, causing a change in the pressure inside the actuator. Under the action of the pressure difference, the push rod of the actuator drives the valve stem and the valve core to move, thereby changing the opening degree between the valve core and the valve seat. For example, when it is necessary to increase the flow rate, the air pressure signal strengthens, and the actuator pushes the valve core to move away from the valve seat, the flow area increases, and the flow rate increases accordingly; on the contrary, when it is necessary to reduce the flow rate, the air pressure signal weakens, and under the action of reset devices such as springs, the valve core moves towards the valve seat, the flow area decreases, and the flow rate reduces accordingly. The bellows sealing structure maintains good sealing performance throughout the process, ensuring that the medium does not leak and guaranteeing the safety of the production environment.
The pneumatic bellows control valve has many outstanding advantages. In terms of sealing performance, compared with traditional packing-sealed valves, bellows sealing can achieve zero leakage or nearly zero leakage, which is especially suitable for occasions with extremely high sealing requirements, such as pipeline systems handling highly toxic chemicals in the chemical industry, effectively reducing the risk of environmental pollution and safety accidents. In terms of regulation accuracy, due to the rapid response and stable action of the pneumatic actuator, combined with the high-precision valve core design, it can accurately control the flow rate, with a control accuracy of ±1% or even higher, meeting the needs of strict control of process parameters in industrial production. In addition, its structure is compact, easy to install and maintain. The bellows assembly has a long service life, can withstand frequent opening, closing, and regulating actions, reducing equipment maintenance costs and downtime.
In practical applications, pneumatic bellows control valves can be found in many industries such as chemical industry, petroleum, medicine, food, and metallurgy. In chemical production, it is widely used in links such as feed control of various chemical reaction kettles and solvent delivery regulation to ensure the stability of reaction conditions; in the petroleum refining process, it can be used to control the reflux flow of crude oil distillation towers to ensure distillation efficiency and product quality; in the pharmaceutical industry, due to its excellent sealing performance and cleanliness, it is often used for the delivery and regulation of high-purity liquid medicines to avoid medium pollution; in the food processing field, it can accurately control the flow of heating media to ensure temperature stability during food processing.
With the continuous improvement of industrial automation, pneumatic bellows control valves are also constantly upgrading. The new type of pneumatic bellows control valve adopts a more advanced intelligent positioner, which can realize seamless connection with the computer control system, support remote monitoring and diagnosis, and further improve the intelligent level and reliability of control. At the same time, in terms of material selection, more high-temperature resistant and strong corrosion-resistant special materials are applied to the manufacture of bellows and valve bodies, enabling them to adapt to more harsh and complex working conditions.
To sum up, with its excellent sealing performance, precise regulation ability, and wide applicability, the pneumatic bellows control valve has become an indispensable key equipment in the field of industrial fluid control, providing a solid guarantee for the efficient, safe, and environmentally friendly operation of industrial production.
