Selection And Application Of Sanitary Normally Open Clamp Diaphragm Solenoid Valves

A sanitary diaphragm valve is used in pharmaceutical and bioprocessing systems to control purified water, gases, media, buffers, and cleaning fluids. Typical applications include water distribution, media preparation, bioreactor feed, buffer transfer, filling, and CIP circuits. A normally open design suits lines that require flow during normal operation and closure after an electrical signal.

Where Is It Used

A sanitary solenoid valve can control flow at several process stages:

1. Purified water: Equipment and point-of-use supply.
2. Media preparation: Water, gas, and process media control.
3. Bioreactor feed: Nutrient and media supply.
4. Buffer transfer: Flow between vessels and filtration units.
5. CIP circuits: Cleaning-fluid control.

A typical process path is:

Purified Water → Media Preparation → Bioreactor → Buffer Transfer → Filtration → Filling → CIP

Why Normally Open

A normally open valve remains open when the solenoid is not energized. It suits circuits where flow is required during normal operation.

1. Fluid passes through the valve.
2. The coil receives a control signal.
3. The actuator closes the diaphragm.
4. Flow stops.
5. Removing the signal returns the valve toward open.

Why Use a Diaphragm Design

A hygienic diaphragm valve separates the process fluid from the actuator through a flexible diaphragm. This supports process isolation and reduces contact between moving parts and the medium.

Key considerations include:

• Low-retention internal geometry
• Cleanable surfaces
• Reliable diaphragm sealing
• Drainability
• Chemical compatibility

An aseptic diaphragm valve may suit processes requiring tighter contamination control and sterilization compatibility.

CIP, SIP and Clamp Connections

CIP requires suitable chemical, temperature, and flow compatibility. SIP requires diaphragm and sealing materials rated for the specified sterilization cycle.

Clamp connections suit assemblies requiring inspection, cleaning, or gasket replacement, while welded joints are intended for permanent piping sections.

Stainless Steel and Selection

The valve can use SS304, SS316, or SS316L. Material selection should match the process fluid, cleaning chemicals, temperature, and corrosion conditions.

The referenced configuration lists a normally open pressure range of 0–0.8 MPa, a temperature range of -5°C to 80°C, and medium viscosity below 50 cSt unless customized.

Five selection checks

1. Medium: Confirm fluid and diaphragm compatibility.
2. Pressure: Check operating and differential pressure.
3. Temperature: Include process and cleaning conditions.
4. Connection: Match clamp dimensions and gaskets.
5. Electrical supply: Match coil voltage with the control system.

Common Problems

• Fails to close: Check coil voltage, control signal, and pressure.
• Diaphragm leakage: Inspect the diaphragm and sealing surfaces.
• Diaphragm damage: Review temperature and chemical exposure.
• Slow response: Check coil condition and differential pressure.

Final Selection Checklist

1. Process medium
2. Normally open control logic
3. Body and diaphragm materials
4. Clamp dimensions
5. Pressure, temperature, CIP/SIP, and electrical limits

The correct configuration depends on the process sequence, fluid conditions, materials, and rated operating limits.

Sanitary Stainless Steel Normally Open Clamped Diaphragm Solenoid Valve

Sanitary solenoid valves are specialized components engineered to maintain hygienic conditions in fluid handling systems. Designed for applications where cleanliness and purity are paramount, these valves offer precise control over liquid and gas flow while minimizing the risk of contamination. 

Sanitary solenoid valves feature a sanitary design with smooth surfaces and minimal dead spaces to prevent bacteria buildup and facilitate easy cleaning. They utilize advanced solenoid technology to regulate the flow of fluids, ensuring accurate and hygienic processing in sensitive environments. With materials such as stainless steel and FDA-approved elastomers, these valves offer excellent resistance to corrosion and chemical exposure.

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