Knife Gate Valves for Slurries, Solids & Severe Service

As a leading manufacturer of knife gate valves, we are committed to delivering durable and dependable fluid control solutions to clients across the globe for various industrial applications.

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Knife Gate Valves Industrial Application

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Explore our comprehensive range of knife gate valves

Resilient Seated Knife Gate Valve

Ideal for slurries and wastewater applications with elastomer seats providing bubble-tight shutoff in low to moderate pressure services.

Temperature range: -40°F to 400°F
Tight shutoff performance
EPDM, NBR, FKM, PTFE options

Metal Seated Knife Gate Valve

Designed for high-temperature abrasive services where soft seats would degrade, featuring durable metal-to-metal sealing.

Temperature: 32°F to 1000°F+
Abrasion resistant
Extended service life

Bonneted Knife Gate Valve

Enhanced protection with fully enclosed design for hazardous or sticky media, preventing contamination and fugitive emissions.

Emission control compliant
Hazardous service rated
Extended packing protection

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Knife Gate Valve – Overview & Applications

Knife gate valves often get talked about only when they fail or when they save the day during a tough shutdown, becoming indispensable for various industrial applications. Anyone who has worked around slurry lines, thick pulp stock, wastewater systems, or wastewater with grit knows how much the right valve can either keep a plant humming or turn routine operations into a constant cleanup.

Choosing and running these valves well is equal parts engineering judgment and field experience. The details matter.

Knife gate valves are designed to cut through media with suspended solids and to isolate pipelines in tough, abrasive services. Their straight-through, full-bore geometry results in minimal pressure drop when open. The thin gate slides between resilient seated arrangements to produce shutoff, and the actuator can be manual, pneumatic, electric, or hydraulic.

They are not the right choice for every duty. These valves shine in low to moderate pressure service, especially where abrasives would chew up globe or ball valves. They struggle with high-pressure gas, fine throttling control, and very high temperatures unless tailored with metallic seats and special trims.

What is a Knife Gate Valve?

A knife gate valve is a linear motion isolation valve with a flat plate, or gate, that moves perpendicular to the flow. The gate edge is often honed or chamfered to shear through fibrous or slurry media. When open, the gate retracts into the body cavity or yoke, leaving a clear, nearly unobstructed passage.

Key characteristics:

Full-bore opening with low pressure loss
Excellent for slurries, fibrous pulp, powders, and viscous fluids
Simple construction with relatively low weight, especially in wafer and lug designs
Best suited for low to moderate pressure classes, commonly up to ASME Class 150 or PN10/PN16 in many models

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Design and Components

Knife gate valves can be bonnetless, semi-bonneted, or fully bonneted. Bonnetless designs are compact and easy to maintain, while bonneted versions protect the gate and packing from contamination and are preferred when fugitive emissions or safety concerns are elevated.

Core components:

Body

Wafer, lug, or flanged pattern, with integral or replaceable seat

Gate

Stainless plate that slides to open or close, sometimes with hardfacing

Seat

Resilient (elastomer or polymer) or metal seated, single or double

Packing

Gland follower with packing rings to seal the stem or gate

Stem and yoke

Rising or non-rising stem, with a yoke supporting the actuator

Actuator

Handwheel, gear operator, pneumatic, electric, or hydraulic cylinder

Materials and Construction

Material selection sets the service window for temperature, pressure, corrosion resistance, and wear life.

Common body and gate alloys:

304/316 stainless steel for general corrosion resistance in water, wastewater, and many chemicals
Duplex and super duplex where chloride stress cracking and erosion are concerns
Carbon steel with coating for non-corrosive slurries, dry powders, or utility duties
Ductile iron as a cost-effective choice in many municipal applications
Hardfacing on gate edges, seats, or liners using Stellite or similar alloys for abrasive slurries

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Technical Parameters Overview

Comprehensive specifications for optimal valve selection

Seat Material Temperature Ranges

Material	Temperature Range	Best Applications
EPDM	-40°F to 250°F	Water, chemicals, not suitable for hydrocarbons
NBR (Nitrile)	-10°F to 212°F	Oils, fuels, moderate chemical resistance
FKM (Viton)	-15°F to 400°F	Broad chemical resistance at higher temperatures
PTFE	-20°F to 400°F	Excellent chemical resistance, lower resilience
UHMWPE	-40°F to 180°F	Abrasion resistance for slurries
Metal Seated	32°F to 1000°F+	High temperature, abrasive services

Pressure Ratings & Standards

Parameter	Specification	Notes
Pressure Class	ASME Class 150, PN10/PN16	Heavy-duty models available in higher ratings
Size Range	DN 50 to DN 1200 (2″ to 48″)	Custom sizes available upon request
Body Styles	Wafer, Lug, Flanged	Choose based on installation requirements
Standards	MSS SP-81, ISO 5208, EN 1092	ASME B16.5 flange connections
Leakage Rate	Per ISO 5208	Soft seats: bubble-tight; Metal seats: Class IV-VI

Bidirectional vs Unidirectional Comparison

Feature	Unidirectional	Bidirectional
Seat Location	One side, upstream pressure	Seats on both sides
Shutoff	Bubble-tight in one direction	Tight in both directions
Best Use	Known flow direction slurry lines	Reversible flow, tank drains
Cost	Lower, simpler construction	Higher due to dual seats
Installation	Must be oriented correctly	More forgiving in mixed conditions

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Common Applications

These valves, often equipped with resilient seated designs, handle severe service conditions in the industry where standard gate, globe, or ball valves fail early due to solids build-up or erosion, making them suitable for various industrial applications.

Mining and Minerals

Tailings, concentrate slurries, lime slurry, thickener underflow, and other industrial applications

Pulp and Paper

Stock lines, recycled fiber, black liquor with corrosion-resistant materials

Wastewater and Sewage

Raw influent, grit removal lines, sludge service applications

Power and Biomass

Fly ash, bottom ash sluice, FGD slurry, biomass digestate

Chemical Processing

Salt slurries, titanium dioxide, catalysts in slurry phase

Food and Beverage

Pomace, spent grain, syrup, and molasses lines in certain grades

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Advantages and Limitations

Advantages

Low pressure drop when fully open
Tolerant of solids and fibers, self-cleaning gate edges
Compact face-to-face, simplifies retrofits
Straightforward maintenance with field-replaceable parts
Wide actuator choices for automated control
Cost-effective isolation in large line sizes

Limitations

Pressure class and temperature limits with soft seats
Not ideal for throttling unless specifically designed
Potential for seat erosion in high-velocity service
Packing leakage if not properly maintained
Gate galling with sticky media without proper coatings
Metal seats have higher leakage rates than ball valves

Useful Rule of Thumb: If you must meter flow precisely or seal high-pressure gas bubble-tight, pick a different valve. If you need to isolate a slurry line at modest pressure and keep maintenance reasonable, a knife gate is a strong candidate.

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