Forged chambers, Rigid construction, Laser welded diaphragm, Optional exotic materials.
Rigid construction, Laser welded diaphragm, Optional exotic materials.
Economical and lightweight, All welded construction, Laser welded diaphragm.
One-piece construction, Laser welded diaphragm, Flushed diaphragm, Ideal for Transmitters.
” I ” section extension type, For flanges below 1″ size, Optional exotic materials.
Large volume type design, Flushed diaphragm, Laser welded diaphragm, Optional flushing ring, For flanges 1″ and above, Optional exotic materials.
Laser-welded diaphragm, Optional flushing ring, Optional exotic materials for flanges 1″ and above.
Extended neck design, Laser welded diaphragm, Optional exotic materials.
Quick connect/disconnect, Laser welded flush diaphragm, Tri-clamp connection.
Quick connect/disconnect, laser-welded flush diaphragm and mating parts are available in accessories.
A trusted diaphragm seal manufacturer and supplier provides one of the most important protective accessories in industrial instrumentation. Wherever process media is aggressive, viscous, toxic, high-temperature, or hygienic, a diaphragm seal isolates the pressure instrument completely while accurately transmitting process pressure, ensuring long instrument life, accurate measurement, and safe operation.
A diaphragm seal, also known as a chemical seal, remote seal, or membrane seal, is a device that isolates a pressure instrument (gauge, switch, or transmitter) from direct contact with the process fluid. A thin, flexible diaphragm separates the process side from the instrument side, with a hydraulic fill fluid filling the space between the diaphragm and the instrument, transmitting pressure accurately without any process fluid entering the instrument.
Diaphragm seals are used when:
The operating principle is straightforward and entirely mechanical:
The entire system is factory-assembled, filled, and leak-tested as a matched unit, ensuring accurate, reliable, and maintenance-free performance.
The most common and cost-effective design. Connects directly to the process via a male or female threaded connection. Suitable for standard pressure tappings in tanks, vessels, and pipelines where flanged connections are not required.
Connects to the process via a raised face or flat face flange. Preferred for higher pressure applications, larger process connections, and installations where threaded connections are not permitted by piping specifications.
Features a completely flush diaphragm face with no cavities or dead spaces. Essential for hygienic, pharmaceutical, food-grade, and highly viscous applications where product entrapment must be eliminated.
Installed directly in the pipeline between two flanges. The process fluid flows past the diaphragm face, ideal for low-flow, high-viscosity, and sanitary applications where a side-mounted tapping is not practical.
Designed specifically for pharmaceutical, food, and beverage applications. Features a tri-clamp, DIN, or SMS connection with a crevice-free, electropolished diaphragm face that meets FDA, 3-A, and EHEDG hygienic standards.
The diaphragm seal is connected to the instrument via a flexible capillary tube filled with hydraulic fluid. Allows the instrument to be mounted remotely, away from high temperatures, vibration, or inaccessible process locations. Available in single capillary and twin capillary (for DP transmitters) configurations.
Mounts directly onto the pressure instrument with no capillary. Compact, rigid assembly with minimal fill fluid volume, providing the best dynamic response and temperature compensation characteristics.
Specially designed for process temperatures exceeding standard fill fluid limits. Features include extended necks, cooling fins, or specialized high-temperature fill fluids to protect the instrument from thermal damage.
Oil & Gas, protection of pressure instruments on crude oil, produced water, H₂S service, and sour gas lines where direct instrument contact is unacceptable.
Chemical & Petrochemical, isolation of instruments from acids, alkalis, solvents, and aggressive organic chemicals in reactors, storage tanks, and process pipelines.
Power Generation, high-temperature steam measurement, boiler drum instrumentation, and condensate system pressure monitoring using capillary seal assemblies.
Pharmaceuticals & Biotechnology, hygienic flush seals on bioreactors, WFI storage, and sterile process vessels meeting FDA, 3-A, and EHEDG requirements.
Food & Beverage, sanitary diaphragm seals on pasteurizers, homogenizers, filling lines, and CIP systems where product purity and cleanability are mandatory.
Pulp & Paper, flushing ring and diaphragm seal combinations on black liquor, white water, and pulp stock lines to prevent clogging and instrument damage.
Mining & Minerals, protection of pressure instruments from abrasive slurries, tailings, and corrosive leach solutions in mineral processing plants.
Semiconductor & Electronics, ultra-high purity diaphragm seals with gold-plated or PTFE diaphragms for aggressive chemical delivery systems in chip fabrication.
Wastewater Treatment, diaphragm seals on sludge, effluent, and chemical dosing line instruments to prevent clogging and corrosion damage.
Q: What is the difference between a diaphragm seal and a chemical seal?
A: They are the same product referred to by different names. Diaphragm seal, chemical seal, remote seal, and membrane seal all describe the same isolation device. The term chemical seal is commonly used in the chemical industry, while diaphragm seal and remote seal are preferred in oil, gas, and general process industries.
Q: Can a diaphragm seal be used with any pressure instrument?
A: Yes. Diaphragm seals are compatible with pressure gauges, pressure switches, and pressure transmitters from all major manufacturers. The instrument connection is standardized, and the seal assembly is factory-matched to the specific instrument being protected.
Q: Does a diaphragm seal affect measurement accuracy?
A: A properly selected and factory-filled diaphragm seal has minimal impact on accuracy. However, temperature effects on the fill fluid can introduce small errors, particularly with capillary seals in environments with large ambient temperature variations. Correct fill fluid selection and capillary length minimization reduce this effect.
Q: What is a capillary diaphragm seal used for?
A: A capillary seal allows the pressure instrument to be mounted remotely, away from the process connection. This is used when the process is at high temperature, in a hazardous or inaccessible location, or when the instrument must be at a convenient reading height away from the process nozzle.
Q: How is a diaphragm seal assembly filled and tested?
A: The complete assembly, diaphragm seal, fill fluid, capillary (if used), and instrument are filled under vacuum in a controlled factory environment. This ensures no air bubbles remain in the fill fluid, which would cause measurement errors. The filled assembly is then pressure-tested and leak-checked before dispatch.
Q: What is the maximum temperature a diaphragm seal can handle?
A: Standard assemblies with glycerine fill fluid handle up to +150°C. High-temperature versions with specialized fill fluids and extended cooling necks handle process temperatures up to +400°C. For superheated steam applications, an extended neck or cooling fin design is recommended.
Q: Are PTFE diaphragms suitable for all chemical applications?
A: PTFE offers excellent universal chemical resistance and is compatible with almost all process fluids, including strong acids, alkalis, and solvents. However, PTFE diaphragms are thicker and less sensitive than metallic diaphragms, making them less suitable for very low-pressure measurement where diaphragm stiffness affects accuracy.
