APV RUF check valves are designed for applications where flow return must be avoided.
Check Valves
2 series from 1 manufacturers
AxFlow UK supplies APV hygienic check valves and non-return valves for preventing reverse flow in food, dairy, beverage, brewing, pharmaceutical and hygienic process systems.
APV check valves automatically allow product to flow in the required direction and close when flow stops or reverses, helping protect pumps, process equipment and product lines from unwanted backflow.
The APV range includes the RUF3 hygienic check valve for demanding, cleanable process applications and the compact VPN non-return valve for cost-effective backflow prevention.
As APV's exclusive UK distributor, AxFlow can help select the correct valve around your product, flow, pressure, temperature, installation orientation, CIP requirements and hygienic standards.
Need help selecting an APV check valve?
Send us your product, line size, flow rate, pressure, temperature, installation orientation and CIP conditions and our hygienic valve specialists can review the application.
What is a check valve?
A check valve, also known as a non-return valve, is an automatic valve that allows fluid to flow in one direction while preventing flow in the opposite direction.
Unlike a manually or pneumatically actuated shut-off valve, a check valve normally operates using the pressure difference across the valve.
When forward pressure is sufficient, the valve opens.
When flow stops, reverses or downstream pressure becomes greater than upstream pressure, the closing mechanism returns the valve towards its seat and helps prevent backflow.
Hygienic check valves are commonly used in:
- Food processing
- Dairy plants
- Breweries
- Beverage production
- Pharmaceutical processing
- Personal-care manufacturing
- CIP systems
- Product-transfer lines
How does a hygienic check valve work?
APV check valves use a spring-loaded closing element.
Forward product pressure acts against the valve disc and spring.
When the available differential pressure is sufficient to overcome the spring force, the valve opens and product flows through the pipeline.
When forward flow stops or the pressure differential reverses, the spring pushes the valve disc towards the seat and closes the flow path.
This automatic operation helps prevent product from travelling backwards through the process line.
Why use a check valve?
Check valves can perform several important functions within a hygienic process.
Prevent product backflow
The primary purpose is to prevent fluid returning through a pipeline after forward flow has stopped.
Protect pumps and equipment
Reverse flow can cause unwanted pump rotation, process disruption or contamination of upstream equipment.
Maintain process direction
Check valves help maintain the intended direction of flow without requiring an actuator or external valve-control signal.
Reduce manual intervention
Because the valve operates automatically from process pressure, it does not normally require an operator to open or close it.
Support hygienic processing
A purpose-designed hygienic check valve combines non-return functionality with cleanable product-contact surfaces and suitable hygienic materials.
When should you use a hygienic check valve?
A hygienic check valve should be considered when fluid must move in only one direction and unwanted reverse flow could affect the process.
Typical situations include:
Pump discharge lines
A check valve can help prevent process fluid flowing backwards through a pump when the pump stops.
Tank filling systems
A non-return valve can help prevent fluid returning from a tank into the filling line.
Product-transfer lines
Check valves can maintain the intended flow direction when pumps start, stop or process pressure changes.
CIP systems
A check valve may help prevent cleaning fluid flowing backwards into an unintended process route.
Parallel equipment
Where several pumps, vessels or process lines connect to a common header, check valves can help prevent unwanted cross-flow between branches.
Check valve vs shut-off valve
A check valve operates automatically based on flow and pressure direction.
A shut-off valve is deliberately actuated to open or close a process line.
| Check valve | Shut-off valve | |
|---|---|---|
| Prevent reverse flow automatically | Yes | Not normally its primary function |
| Intentional process isolation | No | Yes |
| External actuator required | Usually no | Manual or automated |
| Responds to differential pressure | Yes | No |
| Used for process routing | Limited | Yes |
Many hygienic systems use both.
High specification hygienic High specification hygienic Check Valves from AxFlow supported by a network of nationwide technical centres from AxFlow supported by a network of nationwide technical centres
FAQ Check Valves
How do I choose the correct cracking pressure for a hygienic check valve?
Cracking pressure is the minimum upstream pressure needed to open the valve. It should be low enough to avoid unnecessary pressure loss, but high enough to prevent unwanted opening caused by small pressure fluctuations. The right value depends on pump pressure, static head and the operating conditions of the process line.
What causes a hygienic check valve to chatter?
Chatter usually occurs when flow is too low or unstable to hold the valve fully open. This can cause repeated opening and closing, leading to noise, vibration and accelerated seat wear. Correct valve sizing and maintaining sufficient flow velocity can help prevent unstable operation.
How can I minimise pressure loss through a check valve?
Pressure loss can be reduced by selecting the correct valve size and internal design for the required flow. Oversized or restrictive valves can both create poor operating conditions, so pressure drop should be evaluated at the normal and maximum process flow rates rather than selecting purely on pipe diameter.
How do I choose the correct seal material for a hygienic check valve?
Seal selection should consider the product, operating temperature, cleaning chemicals and sterilisation conditions. AxFlow’s APV check valve range is available with materials including EPDM, Viton, HNBR and silicone, allowing the sealing system to be matched more closely to the duty.
When should I replace rather than service a check valve?
Servicing is often appropriate where wear is limited to seals or other replaceable internals. Replacement may be more appropriate if the valve body, seat or guide components are damaged, corroded or no longer capable of maintaining hygienic integrity. AxFlow lists APV check valve designs with serviceable internals for sanitary applications.
