Valves are a crucial component of process design for any industrial manufacturing application that involves fluid handling and processing; they are critical in ensuring liquids, gases, or slurries are delivered to a process in a regulated fashion and for preventing unintended product flow or mixing of fluid streams. At the same time, they must be designed to prevent contamination of product streams and safe, continuous operation of processes that utilize fluids of varying compositions at a wide range of temperatures and pressures.  Sanitary valves are specifically designed to meet strict processing requirements in hygienic industries such as food processing and production that prioritize consistency in product quality and require valves to efficiently and precisely control fluid flow without compromising the state of the product. The ability to provide accurate and reliable flow control for highly-specified applications under hygienic conditions is what ultimately determines the suitability of a certain grade and type of valve. 

Materials and Construction

The standard for sanitary valves is for product-wetted parts (in contact with the fluid) to be made of 316L grade stainless steel and food-grade elastomer seals. Guidelines for elastomer quality are set by organizations such as the FDA (North America) or EHEDG (Europe), and elastomers are chosen primarily as a function of material and temperature compatibility. Common elastomeric seal materials in sanitary valves include: 

  • EPDM (Ethylene Propylene Diene Monomer) — General purpose elastomer suitable for CIP and SIP systems. Often used with hot water/steam applications and in dairy and beverage applications such as milk processing lines.
  • HNBR (Hydrogenated Nitrile Butadiene Rubber) — Notable for its compatibility with oils and general mechanical durability. Often used in applications involving oil-based sauces or processing of meat products containing animal fats and oils. 
  • FKM (Fluoroelastomer, commonly branded as Viton®) — High chemical and thermal resistance, often used in high-temperature applications or caustic cleaning fluid lines material.

Elastomer materials approved by FDA and EHEDG

Valve Styles and Applications 

In order to control the movement of fluids within food processing applications, various styles of sanitary valves are used — the following is an overview of the most common valve styles, their use cases, and examples of applications:  

Single Seat

  • On/Off control of flow for a single fluid (no fine adjustments in flow).
  • The singular seat acts as a sealing element to isolate product flow, but has less contamination protection compared to double seat valves.
  • Minimal internal crevices, compact, simple to clean.
  • Used in transfer applications such as the movement of milk from storage tanks to pasteurizers.

Double Seat (Mixproof)

  • Allows simultaneous flow of two fluid streams (product/product or product/CIP) with minimized cross-contamination risk.
  • Utilizes two independent plugs to isolate the flow chambers, with a leakage chamber in between them.
  • Seal failure results in fluid entering the leakage chamber and draining to the atmosphere, providing a visible indication of the issue without contaminating fluid paths.
  • A cost-effective alternative is the double seal valve, which operates on the same principle but uses a single seat with two seals.
  • Applications include matrix piping networks where fluids such as milk, cream, and cleaning solutions flow in different lines sharing the same routing.

Butterfly 

  • Compact, simple, and cost-effective on/off control or basic throttling via rotating disc.
  • Suitable for low-pressure liquid systems using low viscosity fluids — diminishing ability to seal at larger piping sizes.
  • Typically used at tank outlets or locations in transfer lines where shutoff is desired.
  • Applications include controlling water and CIP fluid flow.

Ball

  • Shutoff control with ability for full-bore design using a rotating ball to open or close the flow bath.
  • Minimal dead space with flow path diameter matching connecting piping to reduce pressure drop.
  • Suitable for viscous or particle-containing fluids such as yogurt.
  • Cannot be throttled but allows for consistent product flow while reducing product stagnation or fouling.

Sanitary valves are able to be surveilled and controlled remotely using valve-top control units fitted with sensors that can be connected to PLC (Programmable Logic Controller) systems. Such control units will contain solenoid valves which receive signals from the PLC to actuate the valve based on the programmed logic; this includes complex automated sequences such as switching from product to CIP flow. They will also indicate the valve position and status locally via LED’s and remotely using built-in sensors. Valve-top control units greatly improve process control and traceability of process happenings while simultaneously eliminating human error, making them particularly essential in hygienic applications such as food processing. 

Sanitary valve with remote valve-top control unit

Maintenance, Fouling, and Lifecycle Cost

Sanitary valves have a number of parts that must be inspected and maintained to ensure continual operation that meets standards for product quality. The elastomeric seals used in the valves wear out over time due to heat, pressure, and chemical reactions with product streams and CIP fluids; they must be replaced regularly according to manufacturer guidelines in the event of cracking, swelling, or compression set (deformation).  The valve must also be inspected regularly for: scratches, corrosion, etc. that can lead to product built-up and contamination, actuator function, sensor functionality, and draining of leakage chambers in mixproof valves.

In the first place, valves, control units, and elastomeric seals must be selected for suitability to the process conditions including temperature and pressure resistance, as well as chemical compatibility, including with CIP fluids. The better the ‘cleanability’ of the valve, the more effective cleaning via CIP fluids will be, and the less maintenance or full equipment turnover that will have to be performed to meet product quality standards. Viscous or sugary food products are particularly difficult to clean and require careful valve and CIP fluid selection to ensure cleanability.


Fouling in food-grade valves  occurs when product residues such milk proteins, sugars, or viscous sauces accumulate on internal surfaces. This build-up can cause poor sealing and introduces contamination risks. Proper valve selection (ex. full bore styles for viscous fluids like yogurt), frequent CIP cycles, smooth surface finishes (Ra < 0.8 µm), and routine inspection are crucial to maintain hygienic operation standards. 

electing the right style of, and correctly specifying a sanitary valve is a critical aspect of any application in the food & beverage production as well as dairy industries. A properly designed sanitary valve will ensure product quality in the short term by preventing stagnation, contamination, and mechanical damage, but also can be relied on to perform its designed function for an extended lifespan via cleanable and durable valve body and gasket designs.