VEOX Mixproof Valve: Separating Two Streams on the Same Valve Block

In food or pharmaceutical plants, multiple product streams and CIP cleaning solutions often share the same valve block. Using a single valve plug to separate them means that even a minor leak can allow caustic or acid CIP fluid to contaminate the product stream, ruining an entire batch. A mixproof valve addresses this risk precisely through its double-seal construction.

A mixproof valve has two independent plugs, each sealing one line. Between the two plugs is a leakage chamber vented to atmosphere. If one plug leaks, the leaked fluid drains into the leakage chamber and exits to the outside where the operator can detect it, rather than crossing into the other stream. This physically separates the two streams — for example, milk running on one side and CIP solution on the other — with two sealing surfaces and a safe buffer zone between them. This is the fundamental difference compared to a butterfly valve or ball valve with a single sealing surface.

Not every position requires a mixproof valve. Sanitary butterfly valves and ball valves already handle most shutoff and diversion points effectively. Mixproof valves deliver their value at the intersections between multiple pipelines — where a product stream and a CIP stream (or two different product streams) are both present and must never be allowed to mix.

• Parallel CIP/production matrix: clean one branch while the other continues supplying product, reducing production line downtime.
• Multi-product tanks: separate milk, fruit juice, beer, or pharmaceutical liquids on the same distribution valve block.
• PMO/high-safety requirements: dairy plants operating under PMO regulations require dedicated mixproof valves to control stream separation.

The Definox mixproof valve range is built around the principle of two independent valve plugs and a safety leakage chamber in between, with an AISI 316L stainless steel body, PEEK/PFA plugs resistant to wear, and EHEDG/3-A hygienic certification. Within this family, VEOX is the standard mixproof configuration; the remaining variants serve specific needs within the same double-seal philosophy.

The entire Definox mixproof valve range covers DN25-150, withstands up to 13 bar, with food-contact seals in EPDM/FKM/PTFE selected according to the process fluid. The dead-zone-free, self-draining design ensures CIP solution reaches every internal surface, minimizing microbial residue.

Mixproof valves are typically part of an automation block, so monitoring open/closed status and coordinating CIP sequences is essential. The Definox Sorio control head provides valve position feedback and CIP process automation support, with AS-i/IO-Link communication protocols, IP67 protection rating, and an ATEX option for hazardous areas. When product recovery from the pipeline is required, the Starmotion pigging system drives a pig through the line to push out remaining product, reducing losses and rinse water consumption.