A21H spring micro opening external thread safety valve is an automatic pressure relief device used to protect the safety of pressure equipment. It adopts the principle of direct spring loading and a micro opening valve disc structure, balancing the system medium pressure through a precisely set spring preload force. When the system pressure exceeds the preset opening pressure, the valve disc slightly opens to release the medium; Automatically shuts off when the pressure drops back to the specified value. The external thread connection method makes its structure compact and easy to install directly on pipelines or equipment interfaces. It is a key accessory to prevent system overpressure and ensure the safety of personnel and equipment. Mainly installed on designated interfaces of pressure systems such as small pressure vessels, water pump outlets, hydraulic systems, air compressor storage tanks, boiler feedwater systems, instrument air ducts, and chemical equipment, as the last line of safety protection to prevent excessive system pressure caused by pressure regulation failure, thermal expansion, or other faults.

A21H spring micro opening external thread safety valve Product Diagram

Features

1. Micro opening release structure

The opening height of the valve disc is 1/40~1/20 of the throat diameter, with rapid opening and closing action and small discharge volume. It is suitable for liquid media or situations that require a small amount of pressure relief.

2. External thread connection, compact and convenient

The inlet and outlet of the valve body adopt standard external threads (such as G thread, NPT thread), with small installation space requirements and easy connection, especially suitable for use in instrument ports, small containers or compact pipelines.

3. The spring is directly loaded and operates reliably

Using spiral compression springs to provide load, the structure is simple, the performance is stable, the opening and closing pressure deviation is small, and the repeatability is good.

4. Alloy steel seal ("H" type)

The sealing surface of the valve disc and seat is made of alloy steel material (such as 13Cr, Stellite) by welding or integral manufacturing, which is wear-resistant, erosion resistant, reliable in sealing, and has a long service life.

5. Adjustable pressure and wide applicabilityBy adjusting the screw, the opening pressure (set pressure) can be adjusted within a certain range. Widely applicable to various liquid media with working temperatures ≤ 300 ℃