A21F-25C external thread ammonia shut-off valve

A21F-25C external thread ammonia shut-off valveExternal thread ammonia shut-off valve, external thread liquid ammonia shut-off valve

Model: A21F-25C, A21H-25C, A21B-25C

Introduction to ammonia shut-off valve:

A21B-25C external thread ammonia globe valve is designed to address the shortcomings of poor corrosion resistance and easy perforation of the shell in ductile iron and carbon steel casting. Based on the specific characteristics of the medium, A105N forged valve body is selected for the gas ammonia globe valve, and multi-stage polytetrafluoroethylene sealing material is used in the sealing device to form a combined seal. It can withstand weak corrosive media such as ammonia, liquid ammonia, oil, liquefied gas, and gas, and can be used under low temperature conditions up to -40 ℃. When using a liquid ammonia shut-off valve, if the nominal pressure of the medium flow direction is lower than PN ≤ 4.0MPa, it is generally adopted to flow downstream, and the medium flows upward from below the valve disc (low in, high out).

External thread ammonia shut-off valve picture - Shanghai Yonglong Valve Factory

Technical parameters of external thread globe valve for ammonia:

Valve body material: A105N

Caliber specification: DN15~DN25

Nominal pressure: PN2.5Mpa

Valve disc sealing: PTFE, Babbitt alloy, hard alloy

Packing: PTFE V-shaped O-ring

External thread liquid ammonia globe valve picture - Shanghai Yonglong Valve Factory

Working principle of external thread ammonia shut-off valve:

A21F-25C external thread ammonia shut-off valveThe opening and closing component of the valve is a plug shaped valve disc, with a flat sealing surface. It is molded with PTFE or welded with Babbitt alloy or hard alloy. The valve stem drives the valve disc to move vertically along the centerline of the valve seat. By relying on the pressure of the valve stem, the sealing surface of the valve disc is tightly adhered to the sealing surface of the valve seat, preventing the flow of the medium. When the handwheel rotates clockwise, the valve stem moves downward and the valve disc descends to seal the sealing surface, cutting off the passage When reversed, it opens and the valve stem is raised to the highest point for sealing.

During the initial operation of the pipeline, there may be particle impurities such as welding slag and rust inside the pipeline. The ammonia shut-off valve can be opened to use the high-speed flow of the medium to wash it away, and then gently closed (cannot be quickly or abruptly closed to prevent residual impurities from damaging the sealing surface), and opened again. Repeat this process multiple times, flush the pipeline, and then put it back into normal operation.

When testing the sealing and valve body pressure of ammonia liquid shut-off valves, manufacturers usually use air pressure and room temperature water. In practical applications, low temperatures may cause cold shrinkage, such as valve stem cover and sporadic air leakage at the joint position. Use a wrench to slightly tighten the cap and the joint is sufficient. Proper, orderly, and effective maintenance will protect valves, enable ammonia water to function properly, and extend its service life.

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