Knife gate valves from DN50 - DN600 PN10: Made in EU

Knife gate valves & slide gates – pneumatic and manual models in stainless steel and cast iron for industrial pipelines

Knife Gate Valves Handwheel

Pneumatic Knife Gate Valves

Knife Gate Valves Lever

PRODUCT CONFIGURATOR

Pneumatic Knife Gate Valves: Powerful and Versatile

When we talk about performance and configurability, we mean our pneumatic knife gate valves. Designed for the correct size, the pneumatic cylinders deliver exceptional performance for the desired application. These pneumatic gates can be easily controlled with a solenoid valve and can also be equipped with inductive position sensors. Of course, we take care of everything!

Electric Knife Gate Valves: Effective, Efficient and Simple

For precise control and straightforward operation, we also offer knife gate valves with electric actuators, particularly from market leaders such as AUMA and Bernard/Deufra. We take care of the design, assembly, testing, and delivery of the complete unit so that you can integrate it seamlessly into your system. For a non-binding quote and technical advice, please contact us.

Spare Parts and Special Solutions for Knife Gate Valves

Due to the nature of the media being handled, regular maintenance helps extend the valve's service life. We are aware of this and offer you a range of corresponding spare parts. Whether it's a pneumatic cylinder, gate plate, plate seal, stuffing box packing, wear plates, 8° scraper, spindle, deflector cone, U-profile seals, and much more, we supply them all. At Fergo, we specialize in realizing special solutions for knife gate valves. We would be pleased to assist you with our experience and expertise.

Frequently Asked Questions – Knife Gate Valves

A knife gate valve (also called a knife gate or slide gate valve) uses a thin, flat gate with a sharpened leading edge that slides vertically through the flow path to open or close the valve. This sharp "knife" edge is what sets it apart from conventional gate valves:

Cuts through media – The knife-edged gate slices cleanly through slurry, sludge, fibrous materials, and media with a high solid content on closing, preventing the gate from jamming or becoming stuck
Self-cleaning seat – Many models feature an integrated scraper effect at the seat ring, which cleans the sealing surface as the gate closes, extending the service life of the seat elastomer even with abrasive media
Short face-to-face dimension – Knife gate valves are available in wafer (inter-flange) construction, giving them a very compact axial length compared to conventional gate valves – critical for retrofitting into existing pipelines
Full bore when open – The gate retracts fully out of the flow path when open, providing an unrestricted bore with minimal pressure drop
Vertical stem travel – The gate moves linearly up and down; a rising stem (visible position indication) or non-rising stem is used depending on available headroom

Because of these characteristics, knife gate valves are the preferred isolation valve for media that would clog, jam, or rapidly wear a standard ball valve, butterfly valve, or gate valve.

FERGO offers knife gate valves in 3 subcategories covering all standard actuation types, from manual operation to high-speed automated control:

Knife Gate Valves – Handwheel – Manual actuation via handwheel with rising or non-rising stem. Rising stem provides direct visual open/closed indication and ergonomic operation. Non-rising stem requires less headroom above the valve. Available in stainless steel (CF8M / 1.4408) and gray cast iron (GG25); uni- and bi-directional sealing; NBR, EPDM, or metal seat ring; DN50–DN600, PN10. The standard choice for manual isolation duties where automated operation is not required.
Pneumatic Knife Gate Valves – Double-acting pneumatic actuator for automated open/close control. Air supply 4–8 bar; fast switching times; suitable for remote operation via PLC or SCADA; ATEX-capable configurations available for use in hazardous areas. Stainless steel and GG25 bodies; DN50–DN600, PN10. Ideal for automated wastewater treatment plants, chemical dosing lines, and mining processes where manual operation is impractical.
Knife Gate Valves – Lever (Quick-close) – Manual actuation via a quick-close lever mechanism for fast, one-motion opening and closing. Designed for applications where rapid shut-off is required and a handwheel's multi-turn operation is too slow. Typically used at silo outlets, bulk material handling equipment, and emergency shut-off points. GG25 body; DN50–DN300; NBR or EPDM seat; PN10.

All FERGO knife gate valves are Made in EU and available from DN50 to DN600 in standard configurations; custom sizes on request.

FERGO knife gate valves are available in two body materials, each suited to different operating environments:

Stainless steel – CF8M / 1.4408 (AISI 316 / V4A):

Gate: SS316L (1.4404); Stem: SS303 (1.4305)
Excellent corrosion resistance against aggressive media, acids, alkalis, chlorinated water, and environments where rust contamination is unacceptable
Preferred for: food processing, pharmaceuticals, hygienic applications, chemical industry, drinking water, aggressive slurries
Required wherever the medium must not be contaminated by iron corrosion products
Higher material cost – justified by longer service life in corrosive environments

Gray cast iron – GG25:

Gate: SS304L (1.4306); Stem: SS303 (1.4305) – stainless wetted parts despite cast iron body
Good mechanical strength and dimensional stability; economical material cost
Preferred for: municipal wastewater treatment, paper and pulp industry, mining and minerals processing, agricultural irrigation, power generation cooling water
Not suitable for strongly acidic or alkaline media, seawater, or applications requiring full corrosion resistance
Lower acquisition cost – the standard choice for high-volume water/wastewater utility applications

Practical guideline: If the process fluid is corrosive, hygienic, or requires a clean material contact surface → stainless steel. If the fluid is neutral-to-mildly aggressive (municipal wastewater, cooling water, mining slurry) and cost is a key factor → GG25 with stainless steel wetted parts.

Knife gate valve performance in demanding media depends heavily on the correct seat elastomer and sealing construction. FERGO offers:

Seat elastomers:

NBR (Nitrile Butadiene Rubber) – General-purpose elastomer; good resistance to mineral oils, hydrocarbons, sewage, and neutral aqueous media; temperature range −10 °C to +90 °C. Standard choice for wastewater and municipal applications.
EPDM (Ethylene Propylene Diene Monomer) – Excellent resistance to steam, hot water, mild acids, alkalis, and ozone; not suitable for mineral oils or hydrocarbons; temperature range −40 °C to +120 °C. Preferred for chemical and food processing applications.
Metal seat – Hardened stainless steel seat for abrasive media where elastomers would rapidly wear; high-temperature applications above elastomer limits; and media containing coarse solids that would cut through soft seats. Bi-directional metal sealing is available for high-pressure or high-abrasion duties.

Sealing construction:

Uni-directional (single-sided) – Seals against pressure from one direction only; the standard and most cost-effective configuration; sufficient for the majority of isolation applications
Bi-directional (double-sided) – Seals against pressure from both directions; required for reversible flow lines, pump bypass circuits, and any installation where backpressure may act on the closed valve

Integrated scraper packing – Models with PTFE-Synt./NBR/PTFE-Synt. or PTFE-Synt./EPDM/PTFE-Synt. packing combine a self-cleaning scraper action at the gate entry point with the elastomer seat seal, significantly extending service life in media carrying fibres, pulp, or coarse particles.

Pneumatic knife gate valves are the right choice whenever:

The valve must be operated remotely or automatically from a control room or PLC
High cycle frequency makes manual operation impractical (e.g. dosing systems, automated filtration lines)
Fast response times are required – pneumatic double-acting actuators switch in seconds
Compressed air is already available on site (standard in most industrial plants)
ATEX-certified automation is needed for hazardous area classification

Key selection points:

Double-acting actuator – Air required for both opening and closing strokes; maximum force in both directions; the standard for knife gate valves where the gate weight and packing friction require positive actuation in both directions. Note: unlike ball or butterfly valves, spring-return (single-acting) is less common on knife gate valves due to the high actuation force required for large bore sizes.
Control: Pair with a 5/2-way NAMUR solenoid valve (24 V DC) for direct PLC control. Add a Switchmaster limit switch box (IP67 / ATEX) for OPEN/CLOSED position feedback to the control system.
Actuator sizing: Knife gate valves require higher actuation force than equivalent ball or butterfly valves – particularly with fibrous media where the gate must cut through material on closing. Always confirm the actuator torque/force rating against the valve's required operating force.

FERGO supplies pneumatic knife gate valves as factory-assembled, tested units ready for installation.

The stem design of a handwheel knife gate valve determines how the stem behaves during operation and what the installation requirements are:

Rising stem (tige montante):

The stem moves upward as the valve opens and downward as it closes – the stem position directly indicates the gate position at all times
Advantage: Immediate visual position confirmation without any additional indicator; easy to see whether the valve is open or closed from a distance
Requirement: Adequate headroom above the valve equal to at least the full stroke length of the gate (i.e. one full bore diameter above the handwheel)
Standard choice when headroom is available and visual position indication is a priority

Non-rising stem:

The stem rotates in place and does not extend upward – the valve occupies a fixed height envelope regardless of gate position
Advantage: Minimal installation height; suitable for installations in confined spaces, low-clearance ceilings, or underground chambers
Requirement: A separate position indicator (e.g. visual indicator disc on the handwheel, or an electronic limit switch) should be used to confirm valve status, as the gate position is not externally visible
Preferred in underground installations, valve pits, and compact mechanical rooms

Knife gate valves are specifically engineered for media that conventional valves cannot handle reliably. Typical industries and applications:

Municipal and industrial wastewater treatment – Isolation of sludge lines, raw sewage channels, aerated grit chambers, sludge thickeners; GG25 body with NBR or EPDM seat; the most common application globally
Paper and pulp industry – Control of wood pulp, paper stock, black liquor, and fibrous slurries; the sharp gate edge cuts through fibres on closing; scraper packing prevents fibre build-up at the gland
Mining and minerals processing – Isolation of ore slurries, tailings, mineral concentrates, abrasive slurries; metal seat for wear resistance; stainless steel for corrosive mine water
Chemical industry – Isolation and on/off control of aggressive liquids, chemical slurries, and process fluids; stainless steel 1.4408 body and gate; EPDM or metal seat depending on chemical compatibility
Food and beverage / agriculture – Handling of grain, starch slurries, vegetable mash, fermentation residues, and agricultural waste; stainless steel body for hygiene; EPDM seat for steam-in-place cleaning compatibility
Power generation – Isolation of cooling water circuits, ash slurry transport, and coal preparation plant drainage; GG25 body with large nominal sizes up to DN600
Silo and bulk material handling – Quick-close lever models for direct mounting beneath silo outlets, hoppers, and conveying equipment; fast one-motion closing to stop bulk material flow

All three are isolation valves, but they are engineered for fundamentally different media types and installation conditions:

Choose a knife gate valve when:

Media contains solids, fibres, slurry, sludge, or suspended particles that would clog or damage other valve types
Self-cleaning gate action (scraper effect) is needed to prevent solids build-up at the seat
Large nominal sizes (DN50–DN600) are required at low pressure (PN10)
Compact face-to-face (wafer construction) is needed for retrofitting into existing pipe systems
Cost efficiency is important at large bore sizes handling non-clean media

Choose a gate valve (wedge gate) when:

Media is clean (drinking water, gas, steam, clean process fluids)
Higher pressure ratings are required (PN16–PN40 or ANSI Class 150–300)
DVGW certification for drinking water or gas is required
Metal-to-metal sealing for high-temperature or high-pressure steam service is needed

Choose a butterfly valve when:

Media is clean to moderately loaded (water, HVAC, air handling, dilute slurries)
Very large nominal sizes (DN200–DN1200) are needed at lowest possible cost and weight
Throttling (partial flow control) as well as isolation is required
The disc obstruction in the flow path is acceptable (butterfly valves are not full bore)

Knife Gate Valves for Industrial Pipelines and Plants

Stainless Steel and Gray Cast Iron Knife Gate Valves

PRODUCT CONFIGURATOR

Product configurator

Pneumatic Knife Gate Valves: Powerful and Versatile

Electric Knife Gate Valves: Effective, Efficient and Simple

Spare Parts and Special Solutions for Knife Gate Valves

Frequently Asked Questions – Knife Gate Valves