Ⅰ. Product Introduction
The spring micro-opening external thread safety valve is a critical overpressure protection device designed for industrial pipelines and equipment. Adopting a spring-loaded structure, it relies on the pre-tightening force of the spring to press the disc against the nozzle seat, ensuring the valve remains closed under normal working pressure. When the medium pressure exceeds the set safety value, the spring is compressed by the pressure, and the disc lifts slightly to discharge the excess medium, thereby reducing the system pressure. Once the pressure drops back to the allowable range, the valve automatically closes under the action of the spring force, preventing unnecessary medium loss.
This series of valves features an external thread connection, which is compact in structure and convenient for installation in narrow spaces. According to different material configurations and sealing surface treatments, the product is divided into multiple models such as A21F-16C, A21W-16P, and KA21Y-16C, to meet the overpressure protection needs of various media and working conditions. Specifically, A21F and A21H-C type valves are suitable for equipment and pipelines conveying media such as air, ammonia, and petroleum gas, with a maximum operating temperature of 200℃. A21W-P and R type valves are engineered for corrosive gas and liquid media, also with an operating temperature below 200℃. KA21Y type valves are specially designed for liquefied petroleum gas, with an operating temperature limit of 100℃.
Ⅱ. Product Features
- Precise Overpressure Protection: Adopts a spring micro-opening structure, which can quickly respond to system pressure changes and accurately control the opening pressure, providing reliable overpressure protection for equipment and pipelines.
- Diversified Material Configuration: Multiple material combinations are available for key components such as the valve body, disc, and spring, adapting to different media characteristics (including corrosive media) and expanding the application range of the product.
- Excellent Sealing Performance: The sealing surface adopts various treatment processes such as stellite overlaying, D507 electrode overlaying, and PTFE lining, ensuring tight sealing under normal working conditions and effectively preventing medium leakage.
- Compact Structure & Easy Installation: External thread connection design, small in size and light in weight, which is convenient for installation and disassembly in limited space, and reduces the difficulty of on-site construction.
- Simple Adjustment & Maintenance: Equipped with an adjusting nut and a locking nut on the top, the opening pressure can be easily adjusted on site without complicated tools. The number of wearing parts is small, and the maintenance cost is low.
- Stable Working Performance: The spring guide structure ensures the stable lifting of the disc, avoids jamming during operation, and the product has good fatigue resistance, which can work stably for a long time under cyclic pressure changes.
Ⅲ. Technical Data
1. Product Series
| Model Series |
|---|
| A21F-16C |
| A21H-16C |
| A21H-40 |
| A21H-64 |
| A21Y-100 |
| A21H-160 |
| A21W-16P |
| A21W-40P |
| A21F-40P |
| A21W-64P |
| A21W-100P |
| A21W-160P |
| KA21Y16C |
| KA21Y-16P |
| A21Y-16R |
| A21Y-40R |
| A21Y-64R |
| A21Y-100R |
| A21Y-160R |
2. Main Parts Materials
| No. | Name of Part | KA21Y-C Materials | A21W-P/A21F-P Materials | KA21Y-P Materials | A21Y-R Materials |
|---|---|---|---|---|---|
| 1 | Union | 20 | 1Cr18Ni9Ti | 1Cr18Ni9Ti | 1Cr18Ni12Mo2Ti |
| 2 | Union nut | 35 | 2Cr13 | 1Cr18Ni9Ti | 1Cr18Ni9Ti |
| 3 | Nozzle | 35 | 1Cr18Ni9Ti | 1Cr18Ni9Ti | 1Cr18Ni12Mo2Ti |
| 4 | Body | 2Cr13 | 1Cr18Ni9Ti | 1Cr18Ni9Ti | 1Cr18Ni12Mo2Ti |
| 5 | Disc | 2Cr13/2Cr13+PTFE | 1Cr18Ni9Ti/1Cr18Ni9Ti+PTFE | 1Cr18Ni9Ti/1Cr18Ni9Ti+PTFE | 1Cr18Ni12Mo2Ti |
| 6 | Spring washer | 2Cr13 | 1Cr18Ni9Ti | 1Cr18Ni9Ti | 1Cr18Ni12Mo2Ti |
| 7 | Spring | 50CrVA | 50CrVA Coated Teflon | 50CrVA Coated Teflon | 50CrVA Coated Teflon |
| 8 | Locking nut | Q235-A | 2Cr13 | 1Cr18Ni9Ti | 1Cr18Ni9Ti |
| 9 | Spring guide | 2Cr13 | 1Cr18Ni9Ti | 1Cr18Ni9Ti | 1Cr18Ni12Mo2Ti |
| 10 | Adjusting nut | Q235-A | 2Cr13 | 1Cr18Ni9Ti | 1Cr18Ni12Mo2Ti |
3. Sealing Surface Material Code
| Code | Sealing Surface Material Process |
|---|---|
| Y | Co Depositing Stellite |
| H | Depositing D507 |
| W | Body Material Sealing |
| F | PTFE Lining Sealing |
4. Basic Technical Parameters
| Item | Specification |
|---|---|
| Valve Type | Spring Micro-Opening External Thread Safety Valve |
| Connection Method | External Thread (GB, ANSI, DIN Standard Optional) |
| Nominal Pressure (PN) | 16, 40, 64, 100, 160 (Bar) |
| Operating Temperature Range | ≤100℃ (KA21Y Type for LPG); ≤200℃ (Other Types) |
| Applicable Medium | Air, Ammonia, Petroleum Gas, Liquefied Petroleum Gas, Corrosive Gas/Liquid, etc. |
| Structural Feature | Spring Loaded, Micro-Opening, External Thread Connection |
| Opening Pressure Adjustment | Adjustable via Top Adjusting Nut (with Locking Nut for Anti-Loosening) |
| Main Body Material Series | C (Carbon Steel); P (1Cr18Ni9Ti Stainless Steel); R (1Cr18Ni12Mo2Ti Stainless Steel) |
Ⅳ．The main shape and connection size
| Type | Nominal
Diameter |
do | d | D₀ | M | d₁ | D₁ | L | L₁ | ≈H |
| KA21-16C A21H-16C A21H-40 A21W-16P A21W-40P KA21-16P |
15 | 12 | 15 | 20 | M27×1.5 | G1/2″ | 30 | 35 | 76 | 66 |
| 20 | 16 | 20 | 25 | M33×1.5 | G 3/4″ | 34 | 40 | 87 | 68 | |
| 25 | 18 | 25 | 31 | M39×1.5 | G1″ | 40 | 50 | 100 | 105 | |
| A21Y-64 A21Y-64P A21Y-100 A21Y-100P |
15 | 10 | 15 | 25 | M39×1.5 | G1 | 44 | 50 | 100 | 66 |
| 20 | 10 | 20 | 31 | M39×1.5 | G1” | 44 | 50 | 100 | 68 | |
| 25 | 12 | 25 | 31 | M39×1.5 | G1 | 44 | 50 | 100 | 105 | |
| A21W-160 /160P |
15 | 8 | 20 | / | M24×2 | G1″ | 44 | 52 | 100 | 261 |
| 20 | 8 | 25 | / | M33×2 | G1″ | 44 | 52 | 100 | 261 | |
| 25 | 8 | 28 | / | M36×2 | G1 | 44 | 52 | 100 | 285 |
