In the world of industrial process control and pressure management, safety is everything. One crucial component in maintaining that safety—especially in high-pressure systems—is the relief valve. Among the most trusted names in this domain is Kunkle, a brand synonymous with reliability and engineering excellence for over a century.
In this in-depth post, we’ll explore what Kunkle relief valves are, how they work, their types and specifications, the industries that use them, and how to select the right valve for your system.
Table of Contents
- Introduction to Relief Valves
- What Makes Kunkle a Trusted Brand?
- How Do Relief Valves Work?
- Key Features of Kunkle Relief Valves
- Applications Across Industries
- Selecting the Right Kunkle Valve
- Installation and Maintenance Tips
- Compliance and Certification
- Common Issues and Troubleshooting
- Conclusion
1. Introduction to Relief Valves
Relief valves are safety devices designed to prevent pressure build-up in piping systems, tanks, or vessels. When system pressure exceeds a predetermined level, the valve opens to allow the release of excess pressure, ensuring the safety of equipment and personnel.
These valves are crucial in:
- Boilers
- Compressors
- Heat exchangers
- Storage tanks
- Pipelines
Without a properly functioning relief valve, overpressure can cause system failure, explosions, or catastrophic damage.
2. What Makes Kunkle a Trusted Brand?
Founded in 1875, Kunkle Valves has become one of the most respected manufacturers of pressure relief valves in the United States and around the globe. Kunkle specializes in valves for steam, air, gas, and liquid service, serving industries ranging from chemical processing and food & beverage to power generation and HVAC.
Why Kunkle?
- Over 100 years of manufacturing excellence
- ASME-certified relief valves
- Broad range of materials and configurations
- Rigorous quality assurance
- Strong distributor and service network
Whether you need a valve for a low-pressure application or high-capacity boiler relief, Kunkle offers solutions that meet stringent performance and safety standards.
3. How Do Relief Valves Work?
Relief valves are mechanical devices that remain closed under normal operating conditions. They open automatically when pressure exceeds a set threshold, and close once safe pressure levels are restored.
Operation Steps:
- Normal Pressure:
Valve remains sealed as the internal spring holds the disc in place against the seat. - Excess Pressure Detected:
As pressure builds, it pushes against the spring-loaded disc. - Valve Opens:
Once the set pressure is exceeded, the disc lifts, allowing excess fluid or gas to escape. - Pressure Normalizes:
The spring forces the disc back into place, resealing the valve.
This process occurs instantaneously and automatically, making it a reliable failsafe in pressurized systems.
4. Key Features of Kunkle Relief Valves
Kunkle designs valves that are not only durable and high-performing but also customizable for a wide range of operating environments.
Common Features Include:
- Construction Materials:
Brass, bronze, stainless steel, cast iron, and steel for compatibility with various fluids and temperatures. - Pressure Ratings:
From low-pressure HVAC systems to high-pressure steam boilers (typically 15–6,000 PSI). - Temperature Ranges:
Designed for both cryogenic and high-heat applications, ranging from -320°F to 800°F. - Valve Types:
- Safety Relief Valves
- Pressure Relief Valves
- Vacuum Relief Valves
- Liquid Relief Valves
- End Connections:
Flanged, threaded, and welded connections for easy integration into different systems. - ASME Section I and VIII Compliance:
Certifies valves for steam, air, gas, and liquid applications.
5. Applications Across Industries
Kunkle valves are a cornerstone of safety in multiple industrial environments. Below are some of their most common applications:
a. Industrial Equipment
- Pressure vessels
- Heat exchangers
- Reactors
- Piping systems
b. Steam Systems
- Boilers
- Steam traps
- Heat recovery systems
- Autoclaves
c. Oil and Gas
- Refineries
- Offshore platforms
- Natural gas pipelines
- Storage tanks
d. Food and Beverage
- Pasteurizers
- Carbonated beverage systems
- Dairy processing equipment
e. Water and Wastewater
- Water treatment plants
- Pumping stations
- Desalination facilities
6. Selecting the Right Kunkle Valve
Choosing the appropriate valve involves careful evaluation of your system’s requirements.
Key Selection Criteria:
- Set Pressure:
Determine the maximum allowable working pressure (MAWP) and select a valve with a slightly higher set point. - Service Type:
Steam, air, liquid, or gas—Kunkle offers different valves for each medium. - Material Compatibility:
Ensure the valve materials are compatible with the fluid’s chemical composition. - Flow Rate (Capacity):
Use Kunkle’s flow charts or sizing software to determine the right orifice size and valve configuration. - Temperature Tolerance:
Match the valve to your system’s operating and ambient temperatures. - Certifications:
Ensure compliance with ASME, NB (National Board), and API if required.
Always consult with an experienced distributor or engineer to ensure the correct selection for safety and regulatory compliance.
7. Installation and Maintenance Tips
Proper installation and maintenance are crucial for ensuring optimal performance and extending the lifespan of your Kunkle relief valve.
Installation Tips:
- Install vertically unless otherwise specified.
- Place as close to the pressure vessel as possible.
- Avoid installing valves where discharge could pose a hazard.
- Use clean piping and ensure no debris enters the valve during installation.
Maintenance Best Practices:
- Annual Testing:
Periodic testing under pressure is recommended to confirm functionality. - Visual Inspections:
Look for signs of leakage, corrosion, or wear. - Cleaning:
Clean internal components as part of routine preventive maintenance. - Seal Replacement:
Over time, seals may degrade and should be replaced as needed. - Documentation:
Keep a record of all inspections, tests, and maintenance work for compliance audits.
8. Compliance and Certification
Kunkle relief valves meet a variety of industrial and safety standards, ensuring peace of mind for operators and engineers.
Certification Highlights:
- ASME Section I & VIII:
For boiler and pressure vessel applications. - National Board Registration:
Many Kunkle valves are NB-certified, making them suitable for interstate commerce and insurance compliance. - PED (Pressure Equipment Directive):
Valves designed for European markets are compliant with CE marking. - API Standards:
Select valves meet API 526/527 requirements for pressure relief.
These certifications ensure that the valves meet stringent quality, safety, and performance requirements across international markets.
9. Common Issues and Troubleshooting
Even the best-engineered valves can experience issues if not maintained properly. Here are some typical problems and their solutions:
| Problem | Possible Cause | Solution |
| Valve leaks constantly | Dirt or scale on the seat | Clean or replace seat and disc |
| Valve doesn’t open | Spring too strong or set pressure too high | Recheck set pressure and spring calibration |
| Valve opens prematurely | Incorrect set pressure | Verify system pressure and valve specifications |
| Noisy operation | Chattering due to backpressure | Install pressure dampeners or size valve appropriately |
| Valve won’t reseat | Damaged disc or spring | Replace damaged components |
If persistent problems occur, consult Kunkle’s technical documentation or a certified service provider.
10. Conclusion
In high-pressure systems, safety valves are your last line of defense, and no one understands this better than Kunkle. Whether you’re operating a small boiler system or a complex petrochemical facility, Kunkle relief valves offer the performance, compliance, and reliability needed to keep operations safe and efficient.
By understanding how these valves work, where to use them, and how to maintain them, you can protect your equipment, workforce, and bottom line from avoidable pressure-related failures.
If you’re in the market for relief valves or need help sizing one for your system, reach out to a trusted distributor like Control Specialties, Inc.—where industry expertise and engineered solutions come together.
