DeZURIK KSL-LA Slurry Knife Gate Valve Long Body

Packingless slurry knife gate valve with field-replaceable sleeves

The DeZURIK KSL-LA is a long body slurry knife gate valve for on-off isolation of abrasive, high-solids media, wet or dry, with mining, power and aggregate plants named as its natural users. Instead of a conventional packed stuffing box and seats, it uses two compression-loaded rubber sleeves with an encapsulated supporting ring that seal against the gate, against the downstream side and against the atmosphere.

Because the sleeve design needs no gate or stem packing and no flange gaskets, the valve removes typical leak paths and the cavity where solids collect. It gives bi-directional drip-tight shutoff to the full pressure rating, and the gate fully retracts out of the flow path when open.

KSL-LA technical specification

Design features worth noting

The sleeve compression removes the need for flange gaskets and eliminates a cavity at the gate in which solids can collect. A top seal with an integrated plate prevents any discharge of process media from the top when the valve is stroked, while also centering, guiding and supporting the gate. Optional drain plates allow flushing, and integral lifting lugs are standard from 12 in.

The gate is finish ground on both sides and edges for long top-seal and sleeve life, and a strong investment cast gate clip is fitted. On manual valves a bronze yoke sleeve resists corrosion, with a grease fitting for the stem threads, and the stem is stainless steel with single-lead threads to cut operating torque. Open and closed position lock-outs are optional and sized for the full actuator force.

Gate coatings are an option rather than a default: the lubrication-infused, non-stick surface reduces actuating forces and extends sleeve life, which matters on sticky or abrasive solids. Body construction is described as allowing easy repairs, and the flanged design avoids the need for downstream flanges in end-of-line use because the sleeves seal to the atmosphere in the open and closed positions.

Ordering code and accessories

The bulletin prints the order example KSL,6,LA,F1,DI,EPDM,S2,NR,DP*actuator, with actuator sub-codes such as MN-HD16-CS taken from the actuator tables. The code sequence runs style, size, long body design, end connection, body, sleeve, gate, retainer and options such as the drain plate (DP).

Accessories include handwheel extensions, floorstands, stem covers and, for cylinder actuators, filter regulators, speed controls and position switches. Strengthened superstructures are available for valves installed horizontally, and the superstructure itself can be carbon or stainless steel.

Pneumatic cylinder actuators are sized for an air supply of 60 psi (410 kPa) or 80 psi (550 kPa), and the matching code from the actuator table is added to the valve order code. Weight tables in the bulletin list the basic valve and the valve with handwheel, chainwheel, bevel gear, pneumatic or hydraulic actuators, which helps when planning supports and pipe stress. A resistance coefficient K is printed for every size so that equivalent pipe length and head loss can be calculated.

Selecting a sleeve and checking the installation

This is general engineering advice rather than bulletin text. Natural rubber suits many mineral slurries at ambient temperature, EPDM covers hot water and many chemicals, and HNBR is chosen where hydrocarbons or higher temperature are present; always match the compound to the fluid and keep the temperature within the limits above. Install the valve on a supported pipeline so that the actuator and the weight of the superstructure do not load the flanges.

Applications and documents

As general engineering context, sleeved knife gate valves of this type serve tailings, sand and aggregate wash water, cement and fly ash slurries and dewatering lines found in Gulf mining, quarrying and power projects. Check solids size, pH and temperature against the sleeve compound before ordering.

The valve is grouped with related products under Knife Gate & Slurry Valves. Bulletin 52.00-1A (12/2025) is attached with the selection tables; send size, sleeve, gate material and actuator details with your RFQ to Seven Star LLC for a quotation.

Using the KSL-LA in Oman and the GCC

Slurry knife gate valves with replaceable sleeves are used in the region’s mining, mineral processing, cement and power plants, on tailings, concentrate, ash and process slurry lines. The packingless design is useful where leaks from packing would cause housekeeping problems or where operators want to reduce routine maintenance. In remote mine sites, a design that can be serviced on site with spare sleeves is a practical advantage.

Select the sleeve material for the slurry chemistry and temperature, and keep spare sleeves for critical lines. Plan enough space for removing the actuator and the valve sections during sleeve replacement.

Information to send with an enquiry

• Size, pressure and flange drilling
• Slurry type, solids content and temperature
• Sleeve material and actuator type
• Quantity and spare sleeves