Anti-mixing valve core structure and standard flow divider valve

In pasteurization lines, the mixproof valve performs a single safety-critical function: diverting unpasteurized product back to the balance tank until the correct temperature is achieved. When the required temperature is reached, the valve switches to forward flow within one second, sending pasteurized product downstream. The mix proof design ensures two independent seals separate raw and pasteurized streams at all times, preventing cross-contamination even if one seal fails.

Mixproof Principle vs. Standard Divert Valves

Core structure of a 

• Two independent discs (upper and lower), each driven by separate actuators

• A leakage chamber formed between the two seals

• Leakage detection ports for visual or instrument monitoring

How a mix proof valve differs from standard divert valves:

• Standard divert valve: single seal; seal failure causes immediate cross-contamination

• Double seat mixproof valve: dual seals plus leakage chamber; media enters the chamber rather than the opposite pipeline if one seal fails

• Leakage chamber remains vented to atmosphere or under negative pressure, preventing pressure-driven contamination

Pasteurization Divert Sequence Requirements

Divert timing (CIP/SIP compatible):

1. Start-up phase: product passes through the heat exchanger, the mixproof valve directs flow to the balance tank

2. Stable phase: temperature reaches set point (72°C/161°F for 15 seconds), discs switch, product flows to the filler

3. Deviation phase: temperature drops below set point, discs reset within ≤800ms, redirecting flow to the balance tank

Actuator specifications:

• Supply air pressure: 6 bar (87 psi) standard, maximum 8 bar

• Position feedback: proximity sensors indicate disc open/closed status

• Spring fail-safe mode: loss of air pressure drives discs to the "safe position" (balance tank direction)

PMO Compliance Verification Methods

Leakage chamber pressure test (quarterly):

1. Close upstream and downstream valves to isolate the mixproof valve

2. Connect a pressure gauge to the detection port and monitor chamber pressure

3. Acceptance criteria: positive pressure condition ≤0.5 bar; negative condition holds -0.5 bar for 1 minute

Seal integrity test (every 6 months):

1. Apply 1.5 times working pressure (maximum 7.5 bar) to the upstream side of the discs

2. Observe the leakage chamber detection port for any media seepage

3. Acceptance criteria: no visible leakage (visual inspection) or no gauge reading change

Material and Compliance Standards Reference

Installation Orientation and Maintenance Schedule

Installation orientation guidelines:
► Vertical installation (actuator upward): preferred; optimal leakage chamber drainage
► Horizontal installation: verify "UP" marking on the valve body; ensure detection port is on top
► Inverted installation (actuator downward): prohibited; causes chamber fluid entrapment

Preventive maintenance schedule:
► Weekly: manual disc stroke test using the actuator manual override
► Monthly: inspect the leakage chamber detection port for visible leakage
► Quarterly: execute leakage chamber pressure test and record trend data
► Annually: replace seals (or per manufacturer's cycle life recommendation)

The core of mixproof valve operation lies in the coordinated movement of two seals and the leakage chamber. During pasteurization divert sequences, valve opening and closing follow pneumatic actuator commands, with timing directly impacting product safety. 

Specifying a double seat mixproof valve for pasteurization divert service requires five verifications: dual-seal plus leakage chamber configuration is field-verifiable, actuator response time ≤800ms, leakage chamber drains under positive and negative pressure conditions, seals pass 3-A 85-03 thermal cycle testing, and quarterly leakage chamber pressure tests track performance trends. Installation must strictly follow the valve body "UP" orientation marking.

Hygienic Stainless Steel Aseptic Pneumatic Reversing Valve

• The aseptic reversing valve has a diaphragm sealing structure, which avoids the contamination of materials by external organisms during the opening and closing process of the valve.
• The seal is made of Daikin materail and the drum structure design ensures usability and durability to a greater extent, with a lifespan of more than 100,000 times.
• The valve body if forged from SS316L round sttel and precision machined by CNC. The inner surface roughness can reach Ra≤0.4μm.

Product Description