Direct answer · Updated July 2026
Which soft seat material for pulp mill slurry?
EPDM is standard for pulp stock and black liquor slurry up to 120°C — excellent resilience and fibre cutting performance. Specify PTFE for higher temperature or aggressive chemicals.
Get valve quote India · +91 97732 78770 · Indicative price list
Applications
Mining & Tailings
Isolation and line breaking on abrasive slurry, concentrate, and tailings pipelines.
Pulp & Paper
Black liquor, stock, and fibre slurry shut-off with minimal clogging.
Wastewater & Sewage
Raw sewage, grit, and biosolids handling in municipal and industrial plants.
Ash Handling & Power
Fly ash, bottom ash, and FGD slurry isolation in power and cement plants.
Cement & Bulk Solids
Powder, clinker, and pneumatic conveying line isolation.
Chemical Slurry
Viscous, solids-laden, and corrosive process media with SS316 or alloy options.
Complete Knife Edge Gate Valve Range
Flow in one direction — wafer/lug, slurry & pulp service
Shut-off from either direction — self-sealing option
Stellite / SS seat for abrasive ash, dry solids & high temp
EPDM, PTFE, Viton — bubble-tight Class VI closure
Double-acting cylinder, solenoid, limit switches, FRL
Technical Standards
Special Features & Options
- Replaceable full-perimeter soft seat liner
- Bubble-tight closure on fibre and slurry
- EPDM standard for pulp and wastewater
- PTFE for chemical and higher temperature
- Viton for oil-contaminated slurry
- Uni-directional and bi-directional designs
- Pneumatic cylinder packages available
Material of Construction
| Part No. | Part Name | Material / Standard |
|---|---|---|
| 01 | Body / Chest | WCB / CF8 / CF8M / GGG40 |
| 02 | Gate / Blade | SS304 / SS316 polished knife edge |
| 03 | Seat / Liner | Replaceable EPDM / PTFE / Viton / NBR |
| 04 | Stem | SS304 / SS316 |
| 05 | Gland Follower | SS304 with PTFE scraper ring |
| 06 | Packing | PTFE / EPDM compatible |
| 07 | Handwheel | Ductile iron |
| 08 | Bolting | SS304 / zinc plated |
Face-to-Face Dimensions — MSS SP-81 Short Pattern
Typical face-to-face (F-F) dimensions for wafer/lug knife edge gate valves per MSS SP-81 short pattern. Flange drilling per ASME B16.5 Class 150#. Confirm at enquiry for your exact bore and end type.
| DN (mm) | NPS | F-F (mm) | ØD Flange | N Bolts | PCD |
|---|---|---|---|---|---|
| 50 | 2 | 51 | 108 | 4 | 60.3 |
| 80 | 3 | 57 | 190 | 4 | 152.4 |
| 100 | 4 | 57 | 229 | 8 | 190.5 |
| 150 | 6 | 76 | 279 | 8 | 241.3 |
| 200 | 8 | 89 | 343 | 8 | 298.5 |
| 250 | 10 | 114 | 406 | 12 | 362.0 |
| 300 | 12 | 127 | 483 | 12 | 431.8 |
| 350 | 14 | 140 | 533 | 12 | 476.3 |
| 400 | 16 | 152 | 597 | 16 | 539.8 |
| 450 | 18 | 171 | 635 | 16 | 577.9 |
| 500 | 20 | 190 | 699 | 20 | 635.0 |
| 600 | 24 | 222 | 813 | 20 | 749.3 |
Lug type with tapped holes; wafer type with through-holes. DN650–900 and PN16/Class 300 on request.
Also available: Metal-to-metal for dry ash; SS316 CF8M body; ductile iron GGG40 economy wafer type.
Request Knife Edge Gate Valve Quote
Send valve type (uni/bi-directional, seat type), size DN, end connection, actuation (manual/pneumatic), quantity, and application. Engineering response within 24 hours.
Or call +91 97732 78770 · info@supremevalves.in
Frequently Asked Questions
Which soft seat material for pulp mill slurry?
EPDM is standard for pulp stock and black liquor slurry up to 120°C — excellent resilience and fibre cutting performance. Specify PTFE for higher temperature or aggressive chemicals.
What is Class VI bubble-tight closure?
ANSI/FCI 70-2 Class VI means zero visible leakage during seat hydrostatic test — the standard for soft seated knife gates on slurry and wastewater lines.
Can soft seat liners be replaced in the field?
Yes. Replaceable liner design allows seat change without removing the valve from the line — specify spare liner kits on your PO for maintenance planning.