APV are market leaders in hygienic valves have one of the widest ranges of mix proof valves
Mixproof Valves
6 series from 1 manufacturers
AxFlow UK supplies APV mixproof valves for safe separation of products, cleaning fluids and process media in hygienic food, dairy, beverage, brewing, pharmaceutical and personal-care applications.
APV double-seat and double-seal mixproof valves are designed to allow different fluids to pass through intersecting process lines while maintaining separation between them. This makes mixproof technology particularly valuable in automated plants where production, product transfer and CIP cleaning need to operate efficiently without unnecessary process shutdowns.
As APV's exclusive UK distributor, AxFlow can support new valve selection, valve manifolds, automation, genuine spares and upgrades of existing APV installations.
Need help selecting an APV mixproof valve?
Send us your product, pipe size, pressure, temperature, valve function, CIP conditions and existing valve model and our hygienic process specialists can review the application.
What is a mixproof valve?
A mixproof valve, sometimes written as a mix proof valve, is a hygienic process valve designed to maintain separation between two different fluids at an intersection in a process system.
Mixproof valves typically use two sealing barriers with a leakage chamber between them. If a seal becomes compromised, fluid can be directed to the leakage outlet rather than passing directly into the second process stream.
This allows mixproof valves to provide a higher level of process separation than a conventional single-seat shut-off valve.
They are widely used where product safety, CIP efficiency and production flexibility are important.
Typical applications include:
- Dairy processing
- Breweries and beverage production
- Food manufacturing
- Liquid ingredient processing
- Tank farms
- CIP systems
- Hygienic valve manifolds
- Personal-care production
- Pharmaceutical processing
How does a mixproof valve work?
In a double-seat mixproof valve, two valve seats separate the upper and lower process pipelines.
When the valve is closed, the two process paths remain isolated. The area between the sealing points forms a leakage chamber that is normally open or connected to atmosphere.
If leakage occurs across either seal, the fluid can be directed into the leakage chamber rather than directly contaminating the second process line.
When the valve opens, the valve elements move to create the required flow path.
On mixproof valves equipped with seat-lift cleaning, individual sealing areas can also be exposed to cleaning fluid during CIP while process separation is maintained in accordance with the valve design.
The result is a valve technology designed around three priorities:
safe fluid separation, effective cleaning and efficient automated production.
Why use a mixproof valve?
Mixproof valves are particularly valuable where a hygienic process contains multiple products, tanks or CIP circuits.
Reduce the risk of product cross-contamination
Independent sealing barriers help maintain separation between incompatible fluids such as:
product and CIP solution • two different products • product and water • different process batches
Allow more flexible production and CIP
Correctly designed mixproof installations can allow one process route to remain operational while an adjacent route is being cleaned.
This can reduce the need to isolate large sections of the plant every time a CIP cycle takes place.
Improve plant utilisation
In highly automated dairy, beverage and food plants, mixproof valve manifolds can make it possible to route products and cleaning fluids through complex process systems more efficiently.
Provide visible leakage indication
The leakage chamber provides a defined route for fluid if one of the sealing barriers leaks.
This helps distinguish seal leakage from product passing directly into the neighbouring line.
Support automated valve control
APV mixproof valves can be combined with valve-control technology for automated actuation, position feedback and integration with plant-control systems.
APV D4 and DA4 mixproof valves
The APV D4 and DA4 Series represents the current generation of APV double-seat mixproof valve technology for hygienic processing.
The range is designed for reliable separation of dissimilar fluids in applications including food and beverage production, dairy processing, brewing and personal care.
Depending on the selected configuration, D4-series technology can provide:
- Double-seat product separation
- Seat-lift cleaning
- Reduced switching losses
- Hygienic stainless-steel product-contact surfaces
- Pneumatic operation
- Automated position monitoring
- Multiple housing arrangements
- Integration into hygienic valve manifolds
- Modern control-unit options
- Simplified maintenance and seal management
The DA4 provides an advanced ultra-hygienic double-seat configuration and also provides an upgrade route for certain installed APV DA3+ valves.
| Requirement | APV option commonly considered |
|---|---|
| General hygienic double-seat mixproof duty | D4 |
| Advanced ultra-hygienic mixproof duty | DA4 |
| Existing DA3+ installation requiring modernisation | DA4 upgrade option |
| Seat-lift CIP cleaning | Suitable D4 / DA4 configuration |
| Automated valve manifold | D4 / DA4 with appropriate control unit |
| Tank outlet mixproof duty | Dedicated tank-outlet mixproof configuration |
| Specialist high-pressure separation | Specialist APV mixproof / double-seat valve technology |
The final valve should always be selected from the actual process conditions rather than model name alone.
High specification hygienic APV Mixproof Valves from AxFlow supported by a network of nationwide technical centres
FAQ Mixproof Valves
What is the difference between a double-seat and double-seal mixproof valve?
A double-seat valve uses two independently sealing seats with a leakage chamber between them, giving a high level of separation between two fluids. A double-seal design typically uses two sealing elements within a simpler arrangement. The best choice depends on hygiene risk, pressure conditions, cleaning requirements and the level of product separation required.
How does the leakage chamber improve process safety?
The leakage chamber provides a visible or drainable separation zone between the two product paths. If either seat seal leaks, product is directed away rather than crossing into the adjacent line. This helps reduce the risk of cross-contamination and makes seal failure easier to detect.
When is seat lifting required during CIP?
Seat lifting is used to expose otherwise hidden sealing surfaces and the leakage chamber to cleaning fluid during CIP. This improves cleanability without fully opening the valve between two process lines. APV designs such as the DELTA DA3+ incorporate seat-lift functionality specifically to support effective cleaning.
What causes operating leakage in a mixproof valve?
Potential causes include worn or damaged seat seals, incorrect actuator adjustment, contamination on the sealing surface, pressure shocks or component wear. Some modern mixproof designs are engineered specifically to minimise operating leakage and improve resistance to pressure hammer.
When should I consider a high-pressure mixproof valve?
A high-pressure design is appropriate where process pressure is significantly above standard hygienic valve duties, such as certain process, transfer or specialist cleaning systems. AxFlow’s range includes mixproof valve options rated considerably higher than standard sanitary designs, including the APV DELTA DKR.
