ZJHN pneumatic double-seated control valve is an industrial process control execution unit consisting of a multi-spring pneumatic diaphragm actuator and a straight-through double-seated valve body. The valve receives standard 4-20mA DC analog signals or 20-100kPa pneumatic signals from control systems, converting air pressure into linear displacement via the actuator to drive the stem, moving the dual valve plugs relative to the seats. Due to the double-plug structure, the fluid forces acting on the upper and lower plugs are opposite in direction and similar in magnitude, allowing most of the unbalanced force to be offset. With its large allowable pressure differential, high flow capacity, and excellent dynamic stability, the ZJHN series is widely used in petroleum, chemical, power, and metallurgical industries for automated systems requiring high-volume control under significant pressure drops.

Product Image of ZJHN Pneumatic Double-Seated Control Valve

Feature

1.Superior force balance characteristics:The dual-plug design utilizes the principle of mutual cancellation of medium-induced unbalanced forces on the upper and lower plugs. This significantly reduces the output thrust required from the actuator, ensuring high stability under high pressure drops.
2.Significant flow capacity:The dual-channel design provides a larger flow coefficient (Kv value) compared to single-seated valves of the same nominal size, effectively meeting high-volume fluid transportation and regulation needs.
3.Strong dynamic stability:Minimal unbalanced forces result in low fluid disturbance during regulation, effectively suppressing mechanical vibration and fluid noise for stable operation in complex environments.
4.Efficient multi-spring pneumatic drive:Equipped with a compact multi-spring pneumatic diaphragm actuator, overall height and weight are significantly reduced. Paired with a smart positioner, it achieves high precision and repeatability.
5.Intrinsically safe attributes:Driven by compressed air without the risk of electrical sparks, it possesses natural safety features ideal for flammable, explosive, and harsh industrial sites.
6.Fail-safe automatic reset:Can be configured as "air-to-open" or "air-to-close" modes. In the event of air supply failure, the valve automatically resets to a preset safety position via built-in spring pressure.
7.Wide material and environmental adaptability:Bodies are available in cast iron, cast steel, or stainless steel. Internals can be hardened to handle water, steam, oils, and general corrosive chemicals.
8.Mature structure and easy maintenance:Utilizes a classic guiding structure with high component interchangeability. Modular internal designs simplify disassembly, cleaning, and replacement of wearing parts, reducing O&M costs.