The APV safety valve valve is designed for the most hygienic applications.
Safety Valves
3 series from 1 manufacturers
AxFlow UK supplies APV hygienic safety valves, pressure relief valves and vacuum valves for protecting tanks, pumps, pipework and process equipment against unacceptable pressure or vacuum conditions.
Designed for hygienic food, dairy, beverage, brewing, pharmaceutical and process applications, the APV range includes SI2 safety valves, UF4/UFR4 pressure relief valves and VRA/VRAH vacuum valves.
As APV's exclusive UK distributor, AxFlow can help select the correct valve around the process fluid, pressure, relieving duty, vessel or equipment being protected, hygienic requirements and CIP conditions.
Need help selecting an APV safety or pressure relief valve?
Send us the process fluid, equipment being protected, operating pressure, maximum allowable pressure, temperature, required relief capacity and line size and our hygienic valve specialists can review the application.
What is a hygienic safety valve?
A hygienic safety valve is a pressure-protection device designed to open automatically when pressure reaches a defined limit, allowing fluid or gas to discharge so the protected equipment is not subjected to an unacceptable overpressure condition.
In hygienic processing, the valve must combine the required pressure-protection function with considerations such as:
- Hygienic product-contact surfaces
- Cleanability
- CIP compatibility
- Suitable stainless-steel materials
- Appropriate elastomers
- Drainability
- Reliable valve operation
- Serviceability
- Correct pressure setting and relieving capacity
Safety and relief valves are commonly used to protect tanks, vessels, pumps and downstream process equipment.
What is the difference between a safety valve, pressure relief valve and vacuum valve?
Although these terms are sometimes used loosely, they describe different process-protection duties.
| Valve type | Primary purpose |
|---|---|
| Safety valve | Protect equipment against excessive positive pressure |
| Pressure relief valve | Relieve excess process pressure or pressure spikes |
| Vacuum valve | Protect a tank or vessel against excessive negative pressure |
| Pressure-control valve | Maintain or regulate process pressure rather than act solely as an emergency protective device |
Within the APV range, the SI2 is a spring-loaded safety valve for excess-pressure protection, the UF4/UFR4 platform provides hygienic pressure-relief functionality, and the VRA/VRAH range protects tanks and vessels against vacuum.
The correct technology should be selected from the actual protection duty rather than using the terms interchangeably.
Which APV safety or pressure relief valve should I choose?
Start with the equipment and condition being protected.
| Application | APV valve commonly considered |
|---|---|
| Tank or vessel overpressure protection | APV SI2 |
| Pump or downstream equipment pressure relief | APV UF4 / UFR4 |
| Hygienic pressure-relief duty | APV UF4 / UFR4 |
| Existing UF3/UFR3 installation | Upgrade to UF4/UFR4 |
| High-pressure relief duty | Specialist UFHP configuration |
| Aseptic pressure-relief duty | Specialist UFMS configuration |
| Tank or vessel vacuum protection | APV VRA / VRAH |
| Hygienic tank-top protection | SI2 together with appropriate vacuum / tank-top equipment |
Final selection must consider the actual fluid, pressure conditions, relief capacity, temperature, hygienic requirements and applicable pressure-system design requirements.
High specification hygienic High specification hygienic APV Safety Valves from AxFlow supported by a network of nationwide technical centres from AxFlow supported by a network of nationwide technical centres
FAQ Safety Valves
How do I determine the correct set pressure for a safety valve?
The set pressure should be chosen so the valve opens before the protected equipment exceeds its maximum allowable working pressure. It must also allow sufficient margin above normal operating pressure to prevent nuisance lifting. The final setting should consider the vessel or pipework design pressure, process conditions and applicable safety standards.
What is the difference between set pressure, overpressure and blowdown?
Set pressure is the pressure at which the valve begins to open. Overpressure is the additional pressure required for the valve to achieve its rated relieving capacity, while blowdown is the pressure reduction below set pressure needed before the valve fully reseats. All three affect how the valve behaves during an overpressure event.
How does back pressure affect safety valve performance?
Back pressure in the discharge line can reduce the effective pressure differential across the valve and may alter opening pressure, lift and relieving capacity. Excessive or variable back pressure should therefore be considered during sizing, particularly where several valves discharge into a common relief header.
How does seal material affect hygienic safety valve performance?
Seal material should be compatible with the process fluid, operating temperature and CIP chemicals. Incorrect elastomer selection can lead to swelling, hardening or loss of sealing force. AxFlow’s APV safety valve range is available with seal materials including EPDM, Viton, HNBR and silicone.
Why is discharge pipework design important for a safety valve?
Poorly designed discharge pipework can create excessive back pressure, vibration or mechanical loads on the valve. Relief lines should be adequately sized, properly supported and routed so discharged fluid can be handled safely without compromising valve performance.
