Butterfly Valve Seat Types and Selection Guide
What is a butterfly valve seat？
The valve seat of the butterfly valve is used to ensure the sealing performance of the valve, especially the soft sealing valve seat, which has very good sealing performance.
In butterfly valve applications, the disc rests securely on the seat to close and seal the valve. Seats are designed to keep the seal intact despite the thermal, friction, and impact stresses of a process.
Below is a general butterfly valve seat selection guide. When selecting seats, always consult the pressure / temperature charts and corrosion resistant guide or contact butterfly valve supplier for engineering help.
Butterfly Seat material: EPDM (E)
Rated for temperatures -30°F to 250°F. EPDM is an abbreviation of a compound called Ethylene Propylene Diene Monomer. It is also commonly called EPT, Nordel, and EPR. EPDM is used extensively in the HVAC industry due to its resistance to polar compounds such as water, phosphate, esters, ketones, alcohols, and glycols. The EPDM material is also applicable for handling concentrated sulfuric acid, 20% sodium hypochlorite (bleach), chlorinated water for swimming pools, and other alkaline solutions. EPDM is not resistant to hydrocarbon solvents and oils, chlorinated hydrocarbons, turpentine, or any other petroleum based oils.
Butterfly Seat material: BUNA-N (B)
Rated for temperatures 0°F to 180°F. Buna-N is also commonly identified as NBR, NITRILE, or HYCAR. It is an excellent general-purpose elastomer suitable for use with air, water as well as most petroleum oils and greases, automotive gasolines (except those which have additives), alcohols and glycols, L-P gases, propane and butane, fuel oils and many other fluids. It also exhibits good abrasion resistance, and excellent resistance to compression set.
Butterfly Seat material: PTFE (P)
Rated for temperatures -20°F to 300°F. The Teflon liner overlays EPDM which is bonded to a rigid phenolic ring on the outside seat perimeter. The PTFE extends over the seat faces and outsides flange seal diameter, completely covering the EPDM elastomer layer of the seat, which provides the resilience for sealing valve stems and the closed disc.
Butterfly Seat material: VITON (V)
Rated for temperatures 0°F to 300°F. This material offers higher temperature resistance and outstanding chemical resistance. It is resistant to hydrocarbon products and mineral acids, both dilute and concentrated solutions. However, it is never to be used in steam applications and is relatively poor in water service.
The type of butterfly valve seal used depends on the application conditions: temperature, pressure, and type of media. For more information on what pressure and temperature a butterfly valve can tolerate, contact us: VALTECCN(www.valteccn.com) butterfly valve supplier and manufacturer.