Seals - NOSHOK
Industrial seals are used to prevent air and fluid leaks, maintain pressure and deflect contamination between two components by creating a tight enclosure. The type of seal used depends on the surface of the compon...
Categories from NOSHOK (1)
Diaphragm Seals
Diaphragm seals are devices that seal pressure transmitters to prevent process fluid from coming into contact with the inner workings of the transmitter. Centro's diaphragm seals are made from high-quality rubber resistant to wear and tear. They are available in various sizes to fit most pressure transmitters. Centro carries a complete selection of diaphragm seals available to purchase online. In addition, Centro offers a wide range of accessories for diaphragm seals, including replacement diaphragms, o-rings, and mounting brackets. Whether you need a single diaphragm seal or a complete Diaphragm Seal kit, Centro has the products to keep your pressure transmitter working correctly.
Filter
Filter
26 items
content loaded
For wastewater and chemical feed applications, as well as most applications with a corrosive mediaConstructed of corrosion-resistant PP glass fiber reinforced upper housing and PP, PVC or PVDF lower housingProtects pressure or vacuum instruments used on ultra-pure or highly corrosive fluid lines such as demineralized water, sulfuric acid, hydrochloric acid, and caustics100% non-metallic wetted parts assures maximum chemical and temperature compatibility
$380.33$525.26
Low Stock (1)Ships within 1 business day
For wastewater and chemical feed applications, as well as most applications with a corrosive mediaConstructed of corrosion-resistant PP glass fiber reinforced upper housing and PP, PVC or PVDF lower housingProtects pressure or vacuum instruments used on ultra-pure or highly corrosive fluid lines such as demineralized water, sulfuric acid, hydrochloric acid, and caustics100% non-metallic wetted parts assures maximum chemical and temperature compatibility
$380.33$525.26
Low Stock (1)Ships within 1 business day
For wastewater and chemical feed applications, as well as most applications with a corrosive mediaConstructed of corrosion-resistant PP glass fiber reinforced upper housing and PP, PVC or PVDF lower housingProtects pressure or vacuum instruments used on ultra-pure or highly corrosive fluid lines such as demineralized water, sulfuric acid, hydrochloric acid, and caustics100% non-metallic wetted parts assures maximum chemical and temperature compatibility
$380.33$525.26
Low Stock (1)Ships within 1 business day
For wastewater and chemical feed applications, as well as most applications with a corrosive mediaConstructed of corrosion-resistant PP glass fiber reinforced upper housing and PP, PVC or PVDF lower housingProtects pressure or vacuum instruments used on ultra-pure or highly corrosive fluid lines such as demineralized water, sulfuric acid, hydrochloric acid, and caustics100% non-metallic wetted parts assures maximum chemical and temperature compatibility
$380.33$525.26
Low Stock (1)Ships within 1 business day
FAQS
- For vibration-heavy environments, diaphragm seals are generally the superior choice. They use a flexible membrane that physically decouples the sensing instrument from the process fluid, absorbing mechanical vibration before it reaches the gauge or transmitter. Isolation rings, while useful for thermal and pressure isolation, don't offer the same mechanical dampening and can transmit vibration directly to the instrument. If your application involves pump vibration, rotating machinery, or high-cycle pulsation, a diaphragm seal with a viscous fill fluid (such as glycerin or silicone oil) provides the best protection and longest instrument life.
- High-pressure hydraulic cylinders demand seals engineered for extreme load and dynamic movement. The top choices are polyurethane (PU) U-cup seals, which offer excellent wear resistance and high extrusion resistance up to 5,000+ psi; PTFE-loaded composite seals, which provide low friction with outstanding pressure ratings ideal for servo hydraulics; and nitrile (NBR) O-rings with backup rings, a cost-effective standard for static and dynamic high-pressure faces. For pressures exceeding 3,000 psi, always pair dynamic seals with anti-extrusion backup rings to prevent seal deformation into the clearance gap.
- The right material depends on the specific corrosive agent. PTFE (Teflon) is the broadest-spectrum choice — chemically inert to nearly all acids, bases, and solvents, making it the go-to for aggressive chemistry. Viton (FKM) handles fuels, oils, and many acids exceptionally well and offers high temperature resistance. EPDM excels against steam, hot water, ketones, and alkalis but fails with oils. For highly oxidizing acids like nitric or concentrated sulfuric acid, PTFE or FFKM (perfluoroelastomers) are the only reliable options. Always cross-reference your specific fluid, concentration, and operating temperature against a chemical compatibility chart before specifying.
- Industrial seals create a controlled interface that blocks fluid or gas passage through three main mechanisms. Compression sealing is where O-rings and gaskets deform under load to fill microscopic surface imperfections. Lip and dynamic sealing uses flexible lips that ride against a shaft or bore, maintaining contact through spring force or fluid pressure. Labyrinth and clearance sealing relies on non-contact designs that use tortuous paths and pressure drops to resist leakage in high-speed rotating equipment. Effective sealing depends on surface finish, material hardness match, correct compression ratio, and fluid compatibility. Even a perfectly designed seal will fail prematurely if installation damage, contamination, or thermal cycling degrade the sealing interface.
- A diaphragm seal (also called a chemical seal or remote seal) isolates the pressure transmitter's sensing element from direct contact with the process fluid. This serves several critical functions: it protects against corrosive, viscous, crystallizing, or high-temperature media that would damage or clog the transmitter's internals; it allows sanitary cleaning of process lines without exposing the instrument; and it enables remote mounting when the process connection and transmitter must be physically separated. The flexible diaphragm transfers process pressure hydraulically through a fill fluid to the transmitter, ensuring accurate measurement without any process fluid entering the instrument. Seal selection — material, fill fluid, and flush or purge configuration — must be matched to the process conditions for reliable, drift-free performance.