Slide-Gate Valves (Flaps)

Slide-gate flap valves are flow-control units, fitted underneath a hopper, silo or conveyor whose output needs to be controlled, containing a sliding gate inside. When the gate is open, a passage opens for material to flow; in the closed position, the gate covers the entire opening and stops the flow.

They have three main functional uses: full stop (on/off operation), throttling via a partially open position, and direction change (diverter). In a typical dry-bulk flow path, slide-gate valves usually act as cut-offs at silo or hopper outlets; on a conveyor line they are used at flow-diversion points.

The TMD GRUP slide-gate catalogue offers three drive options:

• Motorised (electric): can be integrated into the automation system, allows remote opening/closing. Preferred on continuous production lines together with SCADA/PLC.

• Pneumatic: operates on compressed air, fast response; preferred over electric motors in explosion-sensitive environments (cement dust lines etc.).

• Manual: opened/closed by the operator using a mechanical lever or handwheel. For low-frequency operations and budget-sensitive applications.

Selection is made by TMD GRUP based on the project's automation level, explosion-zone classification (ATEX), opening/closing frequency and response-time requirements.

According to our catalogue, slide-gate flap valves are typically installed at the following points:

Slide-gate flap valves work with all physical forms of dry bulk material: powder, pellet, flake or granule. With the gate open, material flows freely through the valve; in the closed position, the product flow is completely blocked thanks to a properly designed seal.

The critical point is seal selection. Heat-resistant seals for hot materials, chemically resistant seals for aggressive chemicals, FDA-compliant seals for food lines. For every project, TMD GRUP determines the appropriate seal material and sealing geometry according to the properties of the conveyed material.

For highly abrasive materials (such as ore, clinker, lime), the inner surface of the slide-gate housing must be protected against wear. The TMD GRUP production programme offers the following options:

• Carbon-steel housing — general use.

• Internal lining (wear plate, ceramic, polymer) — for highly abrasive materials.

• Stainless-steel housing — for food, pharmaceutical and chemical applications (AISI 304/316).

• Full stainless or HB400/450-grade abrasion-steel housing — for aggressive mining applications.

Selecting the right combination directly affects the lifetime and maintenance frequency of the valve.

Slide-gate flap valves are typically bespoke-sized to fit the geometry of the silo, hopper or conveyor they connect to. Standard square/rectangular cross-sections are the most common; circular or hybrid cross-sections can also be manufactured for special projects. The control travel of the gate is sized according to material density.

For every project TMD GRUP determines the following parameters together with the customer: cross-section size, housing material, drive type, seal class, opening/closing speed, sensor or position-feedback requirements, automation-integration details. The result is a valve fully aligned with both TMD's manufacturing standard and the customer's process needs.

Slide-gate valve projects at TMD GRUP proceed in the following order: connection-point measurement and material-property identification → drive type and housing material selection → engineering design and 3D model → manufacturing (at our Başkent OSB facility) → in-house sealing and function testing → site installation, automation integration → commissioning and operator training.