Customer Case: How A21H/Y/W Safety Valve Solved an Overpressure Hazard for a High-Pressure Air Compressor?

Time：2026/4/8 18:59:12 Category：TECHNICAL ARTICLE Source： Click：

——A true story of how Shanghai WUYUE customized the A21W threaded high-pressure safety valve

In the world of industrial safety, a small safety valve can be the last line of defense against a catastrophic failure. In the spring of 2024, we received an urgent inquiry from a major high-pressure air compressor manufacturer in East China: *“We need a batch of threaded safety valves that can reliably work at 420 bar. The medium is compressed air with trace lubricating oil, and the temperature often reaches 180°C. We’ve tried two imported brands – either the lead time is too long, or they start leaking after frequent start-stop cycles…”*

This requirement fell exactly into the strength of our A21H/Y/W Safety Valve series. The final delivered A21W threaded high-pressure safety valve not only solved the customer’s problem but also became a classic case demonstrating Shanghai WUYUE’s R&D and manufacturing capabilities.

Chapter 1: The Challenge – When Standard Products Meet Extreme Conditions

On the surface, the customer’s need was simple: provide overpressure protection for the after-cooler outlet of their 4-stage centrifugal air compressor. But after deeper analysis, three technical difficulties emerged:

1. Extremely high pressure rating: The compressor’s normal outlet pressure was 380 bar, but the safety valve needed to open precisely at 420 bar. Most threaded safety valves on the market only go up to 160 bar.

2. Harsh combination of temperature and medium: 180°C high temperature + trace oil vapor is a killer for standard sealing materials and springs. Conventional NBR rubber would harden and fail quickly.

3. Limited installation space: The cooler outlet piping was very compact, allowing only male threaded connections with a maximum overall height of 280mm.

The customer’s technical manager, Mr. Wang, admitted: *“We considered imported brands, but their prices were sky-high and delivery would take 6 months. Domestic suppliers either said it was impossible or couldn’t guarantee sealing life under such high temperature and pressure.”*

Chapter 2: The Breakthrough – Customizing the A21H/Y/W Series

After receiving the request, our engineering team immediately turned to our proven platform – the A21H/Y/W/F spring-loaded micro-open threaded safety valve. This series was originally designed for air, petroleum gas, and similar media, with operating temperatures up to 200°C and pressure ratings from 16 bar to 160 bar. But the customer’s 420 bar requirement was beyond our standard product line.

Step 1: Feasibility Study & Selection

We presented two options:

• Option A: Use a flanged A42Y high-pressure safety valve (easily reaches 420 bar). But the customer refused because they couldn’t modify the piping.

• Option B: Reinforce the critical components of the A21W platform while keeping its compact threaded design.

The customer chose Option B because they valued the A21 series’ male threaded convenience (M33×2 or custom threads) and the micro-open structure’s fast response time.

Step 2: Material & Process Innovation

To handle the extreme 420 bar pressure, we made three core modifications:

Step 3: Rigorous Factory Validation

Before shipment, each customized A21W safety valve underwent the following tests on our high-pressure gas test bench:

1. Set Pressure Test: Must open precisely at 420 ± 5 bar (customer required ±3%; we achieved ±1.5%).

2. Seat Leakage Test: After blowdown, hold at 380 bar back pressure for 5 minutes – zero visible leakage.

3. Cycle Test: Simulate field start-stop conditions – 50 full open-close cycles with no performance degradation.

Chapter 3: Delivery – From “Impossible” to “Two Weeks Early”

From signing the technical agreement to delivering the first batch of 20 A21W-420P safety valves, it took us only 45 days – three months faster than the imported solution, and at 40% lower cost.

On installation day, Mr. Wang personally supervised the field test. As the compressor pressure slowly rose to 380 bar, the safety valve remained perfectly seated. At 418 bar, with a crisp “pssst” sound, the valve opened precisely, venting the high-pressure gas through the side outlet. After the pressure dropped to 350 bar, the valve immediately re-seated with a perfect secondary seal.

“The ‘chatter’ and ‘leakage’ we worried about never happened,” Mr. Wang said as he signed the acceptance report. “Shanghai WUYUE not only solved our urgent problem but also proved that domestic safety valves have real technological strength in the high-pressure threaded segment.”

Chapter 4: Beyond This Case – What Else Can the A21 Series Do?

This case is just one example of the A21H/Y/W/F safety valve platform’s remarkable adaptability. Based on the same design, we can provide:

• A21H Type: For non-corrosive gases like air and nitrogen (carbon steel or low-alloy steel body).

• A21W Type: All stainless steel construction for corrosive gases or liquids (e.g., dilute acetic acid, seawater).

• A21F Type: PTFE-lined for LPG (liquefied petroleum gas) or media prone to crystallization or strong corrosion.

• KA21Y Type: Quick-opening/closing structure for high-capacity relief requirements.

Pressure ratings from 1.6 MPa to 42 MPa (16 bar to 420 bar).
Connection sizes from DN15 to DN25 (available with G1/2″ to G1″ male threads, or NPT threads).

Why Do Global Customers Trust Shanghai WUYUE?

• R&D Strength: CAD/CFD simulation capabilities allow rapid custom solutions for non-standard pressure, temperature, and media requirements.

• Manufacturing Heritage: Over 20 years of valve manufacturing experience, with CNC machining centers, heat treatment furnaces, and imported welding equipment.

• Global Standards Compliance: We can design and manufacture according to American (ASME), Japanese (JIS), German (DIN), Russian (GOST), British (BS), and other international standards.

• Worry-Free Service: Installation guidance, on-site commissioning, and 12-month warranty provided.

Get Your Customized A21H/Y/W Safety Valve Solution Today

Is your air compressor, high-pressure reactor, or gas test bench facing overpressure protection challenges? Visit our product page for detailed specifications of the A21H/Y/W threaded safety valve:

🔗 A21H/Y/W/F Spring Micro-Open Closed Safety Valve Product Page

For technical selection support or urgent inquiries, please email foreign_trade@0086pv.com (response within 24 hours), or call the number on our website. Shanghai WUYUE Pump Valve Group Co., Ltd. – redefining high-pressure safety through customized engineering.