316L Stainless Steel Weldable Sanitary Butterfly Valve — 3-Piece Body, Viton

Cematic's 316L stainless steel weldable sanitary butterfly valve is the standard component for fluid control in permanent sanitary installations. Its 3-piece body also allows for disassembling the disc and seal without removing the valve from the pipeline.

Consequently, maintenance is faster and does not require cutting the pipeline or affecting the rest of the circuit.

Its butt-weld connection eliminates fluid retention points that exist in clamp connections, making it the correct solution for sanitary lines where the integrity of the welded circuit is a requirement.

Likewise, its integrated ISO5211 mounting allows for future automation with pneumatic or electric actuators, without needing to replace the valve.

Operation Options — Manual or Automated

This weldable sanitary butterfly valve is available in standard manual operation and can be automated with three actuator options depending on the required level of automation:

• Manual with Lever: Direct operation without electrical or pneumatic power. Therefore, it is the correct option at process points where automation is not necessary or where the operator controls the flow manually. The ISO5211 mounting also allows for installing an actuator in the future without replacing the valve.
• Standard Pneumatic Actuator: Automates with compressed air for quick opening and closing from a PLC. Therefore, it is the most common option in installations with an available pneumatic network. Cematic also delivers the valve + pneumatic actuator assembly, assembled and calibrated, ready for installation. See weldable sanitary butterfly valve with pneumatic actuator →
• Sanitary Pneumatic Actuator: Pneumatic actuator with stainless steel cover for installations where the entire assembly must withstand aggressive environments, frequent washdowns, or areas classified as sanitary. Cematic also delivers the assembled and calibrated unit. Therefore, check availability with the Cematic technical team.
• Electric Actuator: It is compatible with the ISO5211 mounting, so no modification of the valve is required for installation. Therefore, it is a viable option for installations where compressed air supply is not available. Also, consult availability with the Cematic technical team.

Why a 3-Piece Body in a Weldable Valve

The 3-piece body is also the key differentiator of this valve compared to single-body weldable butterfly valves. In a single-body weldable valve, accessing the disc and seal requires cutting the pipeline.

This implies an extended shutdown and welding work on-site. In contrast, the 3-piece body is separated by screws, so the disc and Viton seal are accessible without touching the pipeline. This way, preventive maintenance is carried out in minutes with the line out of service for the shortest possible time.

Weldable vs. Clamp — When to Choose a Weldable Connection

The choice between weldable and clamp, moreover, depends on the type of installation and the operational requirements of the process. The weldable connection is correct in the following cases:

• High-Purity Aseptic Lines: The welded joint has no external gaskets or retention cavities, making it the preferred type of connection in systems where external contamination is unacceptable. The clamp connection, in contrast, has a gasket that can be a microbiological risk point.
• Permanent Installations: When the valve will not be frequently disassembled, welding also offers greater integrity than clamping. It also eliminates the progressive deterioration of the clamp gasket due to temperature and cleaning cycles.
• Greater Pressure Resistance: The welded joint also withstands higher pressures than the clamp connection. Therefore, it is the correct option when the working pressure approaches the upper limit of the system.

Construction Materials

The body is made of 316L stainless steel with a sanitary polished finish, which is the standard material in demanding sanitary applications. Its molybdenum content also offers greater resistance to chlorides and CIP agents than SS304. The disc is also made of SS316L, maintaining material consistency in the fluid contact area.

The seal is made of Viton (FKM), which offers high chemical and thermal resistance. It is also compatible with most aggressive industrial fluids up to 180 °C. Finally, the internal finish Ra ≤ 0.8 µm eliminates surface roughness where microorganisms or product residues could accumulate.

Technical Specifications

Fluid Compatibility

This weldable sanitary butterfly valve with a Viton seal is compatible with the most demanding fluids in sanitary and industrial applications. The main groups are described below:

• Food fluids — juices, milk, beer, wine — SS316L resists the most aggressive CIP agents; also, Viton withstands high temperatures without deforming in cleaning cycles
• Pharmaceutical and cosmetic fluids — materials comply with requirements for direct contact with human consumption products; furthermore, the Ra ≤ 0.8 µm finish facilitates sterilization and prevents microorganism accumulation
• Corrosive chemical fluids — Viton is compatible with a wide variety of acids, solvents, and corrosive products; therefore, this valve is effective in demanding chemical processes where EPDM is insufficient
• Petrochemical fluids and hydrocarbons — the Viton seat is compatible with hydrocarbons, oils, and fuels; likewise, the SS316L body extends service life in corrosive environments
• Steam, hot water, and high-temperature fluids up to 180 °C — Viton maintains its seal integrity above 120 °C; in contrast, EPDM or NBR are limited to 110 °C and 80 °C respectively

Applications of the Weldable Sanitary Butterfly Valve

Food and Beverage Industry

The weldable sanitary butterfly valve is the standard component in food and beverage production lines where a welded connection ensures circuit integrity. Its Ra ≤ 0.8 µm finish also allows for efficient CIP cleaning without disassembling the valve. Consequently, downtime between batches is significantly reduced compared to valves with mechanical connections.

Pharmaceutical and Cosmetic Industry

In pharmaceutical and cosmetic process lines, the welded connection also eliminates microbiological risk points that exist in clamp unions. Therefore, it is the preferred connection type in GMP-validated aseptic systems.

Likewise, the 3-piece body allows for inspection and replacement of the Viton seal without disassembling the valve, which reduces downtime during preventive maintenance.

Chemical Industry

Viton, therefore, resists a wide variety of acids, solvents, and corrosive products that would degrade EPDM or NBR. Consequently, this valve ensures a long service life in demanding chemical environments. In addition, the option of automation with a pneumatic actuator allows for remote fluid control without manual intervention in chemical hazard zones.

Petrochemical Industry and High-Temperature Processes

The Viton seat is also compatible with hydrocarbons, oils, and fuels typical of the energy sector. Furthermore, when processes exceed 120 °C, Viton maintains its seal integrity where other elastomers fail. Therefore, this valve is suitable for steam, hot water, and process liquids at elevated temperatures.

For the complete range of sanitary butterfly valves, see sanitary butterfly valves collection →

Technical Data Sheet