DEMCO Series NEI-T Teflon-Lined Sanitary Butterfly Valve, 2″–10″

The DEMCO Series NEI-T is a Teflon-lined butterfly valve, ideal for "clean lines" in food and beverage plants and for highly corrosive chemical service where the inert, aseptic and non-stick character of Teflon is required. The seat consists of a virgin Teflon liner overlaying and bonded to an elastomer cushion (Buna-N or EPT) which provides resilience for sealing. Available in wafer (short-neck) and lug (long-neck) styles, sizes 2″ through 10″, with the broadest range of corrosion-resistant body and disc materials of any DEMCO series including Hastelloy C and Alloy 20. 150 psi drop-tight shut-off across all sizes.

Construction

• Body configurations: Wafer (short-neck) and Lug (long-neck)
• Size range: 2″ – 10″ (50 – 250 mm)
• End connections: ASME Class 125/150 flanges
• Body materials: Ductile iron, gray iron (lug long-neck), aluminium bronze, carbon steel, aluminium (wafer only), 316 stainless steel, Hastelloy C
• Stem materials: 316 stainless, Monel, Hastelloy C
• Disc materials: 316 SS (polished or unpolished), Alloy 20, Hastelloy C
• Seat elastomers: Buna-N/Teflon (peroxide-cured), EPDM/Teflon (peroxide-cured or sulfur-cured) — virgin Teflon liner overlaying and bonded to elastomer cushion (Buna-N or EPT)
• Bearings: Bronze (standard); throttling discs include 4 stem O-rings for stem sealing.

Performance

• Pressure class: ASME Class 150 (285 psi non-shock body rating).
• Drop-tight shut-off ratings: 150 psi (drop-tight).
• Vacuum: Sealed against 10 microns of vacuum (29.9 in Hg).
• Temperature range: +20°F to +275°F (−7°C to +135°C) — Teflon liner inert across the range.
• Bi-directional sealing: Identical drop-tight closure from either flow direction.
• End-of-line service: Not rated for end-of-line service.
• Flow coefficient (Cv at 90° open): 145 (2″) → 5,000 (10″).

Engineered features

• Virgin Teflon (PTFE) liner — inert, aseptic, non-stick
• Teflon overlays a Buna-N or EPT elastomer cushion for resilience
• Hastelloy C and Alloy 20 body / disc options for the most aggressive chemical service
• Polished or unpolished 316 SS disc for sanitary or chemical applications
• Wafer (short-neck) for between-flange installation; lug (long-neck) for clearance over insulation
• 150 psi drop-tight closure across all sizes
• Same trim-handle range as the NE-I Sanitary series — bronze hub with SS fasteners for caustic wash-down

Typical applications

• Aseptic food and beverage clean-in-place (CIP) loops
• Pharmaceutical purified-water and process service
• Chemical processing — strong acids, caustics, solvents
• Pulp and paper bleach plant
• Specialty cosmetics and personal-care lines
• Semiconductor ultra-pure water and chemical handling

How to order

DEMCO uses an 11-character part number to specify each unique configuration. Build the part number from the base number plus six selection digits:

Example DEMCO base part numbers in this series:

• 24680 (2″, 150 psi)
• 24681 (2½″, 150 psi)
• 24682 (3″, 150 psi)
• 24683 (4″, 150 psi)
• 24684 (6″, 150 psi)
• 24685 (8″, 150 psi)
• 24686 (10″, 150 psi)

For your RFQ, please specify: required size, pressure rating, body configuration (wafer or lug), body / stem / disc materials, seat elastomer, and required actuation. Indus Hydraulics will return an estimate against the corresponding DEMCO base part number.

Compliance & marking

• MSS SP-25 marking standard on every valve.
• Body rating to ASME Class 150 (285 psi non-shock).
• Wafer body diameters self-centre in ASME Class 150 flange patterns.
• Triple stem seal: hard-backed cartridge seat + integral flange seal + dual O-ring stem ribs in the seat bore.

Companion products

Manual handles, weatherproof worm-gear operators, and Series DR pneumatic actuators all interchange on this valve via the DEMCO top-flange standard. Compatible Indus SKUs include IH-VAL-BFLY-HDL-MEM, IH-VAL-BFLY-WGO, IH-VAL-BFLY-DR-DA. For automated installations, also see the position indicator switch, solenoid valve, pneumatic positioner, and seal-repair-kit accessories listed against the corresponding actuator product.