Cast Steel Fully Enclosed Spring-Loaded Low-Lift Safety Valve A21H-16C

Product Description

The A21H-16C spring-loaded low-lift safety valve is suitable for use on equipment or pipelines carrying media such as air, ammonia, and petroleum gas at operating temperatures of ≤200°C. The A21W spring-loaded low-lift safety valve is suitable for equipment and pipelines carrying corrosive gases or liquids at operating temperatures of ≤200°C, while the A21F spring-loaded low-lift safety valve is suitable for equipment and pipelines carrying liquefied petroleum gas, natural gas, and similar media at operating temperatures of ≤200°C, serving as an overpressure protection device. When the pressure inside the equipment or piping exceeds the allowable value, the valve automatically opens and fully vents the pressure; when the pressure drops to the specified value, the valve automatically closes, ensuring the safe operation of the equipment and piping. The A21H/W/F spring-loaded low-lift safety valves are available with two connection methods: male-threaded and butt-weld (BW). When selecting a valve, choose the appropriate connection method based on the on-site operating conditions.

Performance Features

1. Spring-loaded low-lift safety valves feature a simple design, excellent sealing performance, accurate turn-on pressure, high discharge capacity, low reseating pressure differential, and easy adjustment.
2. Nozzle-type valve seat: The valve seat is a Vival nozzle-type valve seat. Steam reaches the speed of sound as it passes through the valve seat outlet, resulting in a high discharge coefficient. The valve seat sealing surface is overlaid with a cobalt-chromium-tungsten hard alloy, making it wear-resistant and erosion-resistant, and ensuring a long service life.
3. Thermoelastic valve: The valve is designed with a thermoelastic structure that utilizes its slight deformation under medium pressure to enhance sealing performance and eliminate pre-leakage in safety valves when the medium pressure approaches the set pressure. The valve's sealing surface employs advanced laser hardening technology, which improves hardness, wear resistance, and impact resistance.
4. Adjustment nut: By adjusting the adjustment nut to change the spring compression, the valve can easily and quickly achieve the precise set pressure.
5. Back-pressure adjustment sleeve: An auxiliary mechanism for adjusting the back pressure on the valve disc. Adjusting the back-pressure adjustment sleeve allows for the achievement of an appropriate seat pressure differential. Turning it clockwise reduces the valve’s back pressure. Turning it counterclockwise increases the valve’s back pressure.

Product Specifications

A21H Male‑Threaded Spring-Loaded Low-Lift Safety Valve Size Guide

A21H Butt-Weld Spring-Loaded Low-Lift Safety Valve Size Guide