Diaphragm Seals

A diaphragm seal is a protective device installed between the process media and pressure instruments such as pressure gauges, pressure transmitters, or pressure switches. It is designed to isolate viscous, corrosive, high-temperature, or crystallizing media, preventing direct contact with the measuring element and improving operational stability and service life. Diaphragm seals are widely used in food processing, chemical, pharmaceutical, semiconductor, and petrochemical industries.

For more detailed information, please refer to this article:
In What Situation Should A Diaphragm Seal Be Integrated to Your Pressure Gauge?

Diaphragm Seals FAQ

Selection questions for diaphragm seals used with gauges, transmitters, switches, and difficult process media.

When should a diaphragm seal be used?

Use a diaphragm seal when media is corrosive, viscous, high-temperature, crystallizing, contaminated, toxic, sanitary, or likely to clog the pressure instrument. The seal isolates the instrument while transmitting pressure through fill fluid.

How do I choose between threaded, flanged, and sanitary diaphragm seals?

Threaded types are common for compact process connections, flanged types are used for tanks and pipelines, and sanitary clamp or DIN/IDF/SMS designs are selected for food, beverage, pharmaceutical, and clean-in-place systems.

Which diaphragm seal is suitable for corrosive chemicals or PCB processes?

For corrosive media, plastic or corrosion-resistant wetted materials such as PP, PTFE, or suitable coated diaphragms may be required. DIT-PP, DIT-P, DIF-P, and upper-metal/lower-plastic designs are examples used for acidic or alkaline media.

Can a diaphragm seal be combined with capillary tubing?

Yes. Capillary tubing is useful when the instrument must be installed away from high temperature, vibration, inaccessible areas, or process connection points. The capillary length and fill fluid should be selected based on temperature and response requirements.

Showing 1–16 of 29 results

Model: DIS-C
Sanitary Diaphragm Seals, Tri-clamp Diaphragm
- Clamp connection, easy to clean and mount
- Used in the food, beverage, pharmaceutical and bio industries
Model: DIS-DIN
Sanitary Diaphragm Seals, DIN Standard
- Flush welded diaphragm seal to assure the best hygiene and quick cleaning
- Especially designed for sanitary application such as dairy and breweries
Model: DIS-IDF
Sanitary Diaphragm Seals, IDF Standard
- Clamp connections are fast and easy to open for cleaning and seal replacement
- Grooved union nut and thread coupling can be selected
- Suitable for Sterilization in Place (SIP) and Clean in Place (CIP)
Model: DIS-SMS
Sanitary Diaphragm Seals, SMS Standard
- Applications for measuring viscous, powdery and clotting hydraulic fluid
- Quick mounting and dismounting, easy to clean from the outside without residue
Model: DIT-S
Threaded Connection, Screwed
- Suitable for measuring corrosive or crystalline media
- The diaphragm can be removed for cleaning when blocked with fluid
- Mostly used in chemical processing and pharmaceutical industries
Model: DIT-W
Threaded Connection, Welded
- Fully welded design, without additional sealing
- For hot, hazardous or toxic media
- Mostly used in oil, gas and petrochemical industries
Model: DIT-H
Threaded Connection, High Pressure
- Recommended for high pressure application
- For corrosive, viscous or sewage media measurement
- Ideal for petrochemical, wastewater technology etc.
Model: DIT-P
Threaded Connection with Corrosion-resistant Plastic
- Made of PTFE/PP to resist strong acids and alkalis effectively
- Separates media from the gauge to prevent internal component damage
- Ideal for viscous or particle-rich fluids, ensuring accurate pressure readings
Model: DIT-USLP
Threaded Connection, Upper Metal, Lower Plastic
- A metal upper body that connects to the instrument is tight and durable
- Large selection of top housings and process connections
- Ideal for processing corrosive fluids or other environmentally harmful medium
Model: DIT-FS
Threaded Connection, Flush Diaphragm
- Threaded connection design for easy installment
- Ideal for application with high pressure and limited space
- Can be used in heavy industries such as mining, tunnel digging, etc.
Model: DIT-PP
Threaded Connection, Intergrated PP
- Polypropylene has excellent anti-corrosion properties
- One-piece molded, rarely cracks or leaks
- Mainly used in printing circuit boards, liquid filter pumps, etc.
Model: DIT-PPS
Threaded Connection, Bottom PP
- Could be integrated with a pointer, digital manometer or transmitter
- Suitable for measuring acidic fluids, which are compatible with Viton
- Suitable for circuit board equipment, the petrochemical industry, etc.
Model: DIT-6
Threaded Connection, Hexagonal
- Detachable design for easy cleaning and maintenance
- Often used in cement plants and the petrochemical equipment industry
Model: DIF
Flanged Connection
- Screw type or welding type can be selected according to size requirements
- Used for sewage or fluids with difficult properties such as corrosive, high temperature, or crystallization
- Applicable for strict working environments including pharmaceuticals, chemical and petrochemical processing, etc.
Model: DIF-DSR
Flanged Connection with Screwed Diaphragm
- Used for rigid working environments and corrosive fluids like high temperature, sewage, high process pressures, and crystallization
- Various types and materials for diaphragm seal bodies that fit any kind of gauge upon request
- The flush port provides easy cleaning/flushing due to process media being prone to clogging
- Extremely high compatibility replacement for the WIKA 990.12
Model: DIF-P
Flanged Connection with Corrosion-resistant Plastic
- The all-plastic material design is lightweight and can effectively measure acidic and alkaline media
- Excellent for paint, electroplating, sewage treatment and the paper industry