What Is a Discharge Valve?
A Discharge Valve is a critical control device in powder and bulk solid handling systems. Its core function is to use an actuator—such as a gate, rotary vane, or flap—to achieve reliable shut-off, precise regulation, and metered feeding of materials like cement, mineral powder, and fly ash. In pneumatic conveying systems, it acts as an airlock feeder (Rotary Feeder) to prevent pressure loss. At silo bottoms, it serves as a Slide Gate Valve or Double Flap Valve to ensure sealed discharge. It can be integrated with DCS/PLC systems via electric, pneumatic, or hydraulic actuation for automated control, effectively solving industrial challenges such as material bridging, abrasive wear, and dust emission, thereby ensuring continuous, efficient, and environmentally compliant operation in cement plants, power plants, and chemical processing facilities.
Double Flap Valves for Sealed & Abrasive Material Discharge
We provide high-performance double flap valves for airtight discharge in demanding industries like cement and mining. Our robust cast iron and stainless steel valves ensure zero leakage when handling abrasive powders (e.g., fly ash, cement clinker) and corrosive media. Key models include explosion-proof options for flammable dust (meeting ATEX/ExdⅡCT4) and wear-resistant designs for high-pressure systems.
Driven by a pneumatic actuator, ensure that at least one layer of the valve plate is always in a closed position.
Equipped with an electric actuator (including reducer, crank, cam, and other components), supporting variable frequency speed control.
Equipped with a counterweight balance system , achieving automatic reset of the valve plate through the lever principle.
The air locking and unloading function is achieved by the alternating action of a single valve plate.
By alternating the plate, a continuous unloading cycle is formed, enhancing the ability to resist material jamming.
Rotary Valves | Precision Feeding, Sealed & Explosion-Proof Discharge Solutions
As critical components for pneumatic conveying systems, our Rotary Feeder Valves provide precise and reliable control for powders and granules. From A-type rotary valves compatible with screw conveyors to B-type rotary valves for direct connection to square pipelines, we meet various interface needs. For severe service conditions, we offer corrosion-resistant stainless steel rotary valves, abrasion-resistant cast iron rotary valves, as well as double-axis rotary valves and explosion-proof rotary valves (ExdⅡCT4) designed for high-pressure differentials (0.6 MPa) and flammable & explosive dust environments. They are the ideal choice for discharge from vertical mills and cyclone dust collectors.
Used in conjunction with screw conveyors and chain conveyors for sealed discharge.Functions as a crucial airlock feeder in pneumatic conveying systems, maintaining system pressure stability during continuous feeding to prevent air backflow and improve conveying efficiency.
Compatible with square pipelines or hopper interfaces for easy direct installation.Its square flange design allows for seamless direct connection to hoppers, dust bins, or square conveying ducts, simplifying installation. It is an ideal compact solution for space-constrained applications.
Stainless steel can withstand acids, alkalis, high temperatures , and corrosive media.The smooth surface and corrosion-resistant properties meet food-grade and pharmaceutical-grade hygiene standards. It is the preferred choice for handling salty, sugary, or chemically active materials, offering easy cleaning and contamination prevention.
The cast iron casing has high hardness, making it suitable for abrasive materials .The robust cast iron housing and rotor are specifically designed for highly abrasive bulk materials like sand, foundry sand, and mineral granules, delivering extended service life in harsh environments such as concrete batching plants or foundry workshops
More impact-resistant, making it suitable for high-load or foreign object-laden conditions.Utilizing high-strength drive chains, it can withstand instant impact from large lump materials or accidental foreign objects, effectively preventing jamming. It is particularly suitable for solid waste handling systems with complex conditions, such as waste processing and recycling plants.
Suitable for high pressure differences (0.6 MPa) or flammable and explosive dust.The unique dual-shaft, four-vane design creates a double seal, capable of withstanding pressure differentials up to 0.6 MPa. It is a reliable solution for safe discharge in dense phase pneumatic conveying and fluidized bed systems, as well as for flammable and explosive dusts like coal powder and aluminum powder.
Explosion-proof design meets high-level standards such as ExdⅡCT4.The complete unit features explosion-proof motors, explosion-proof junction boxes, and spark-free materials, certified to ATEX/ExdⅡCT4 standards. It is specifically designed for hazardous areas with explosive dust atmospheres in industries like chemicals, paints, and metal processing.
Discharge highly abrasive powders from vertical mills and cyclone dust collectors.Key wear parts like the rotor and housing are lined with replaceable chromium carbide wear plates or ceramic tiles. It is specifically engineered to handle the continuous erosion of super-fine, highly abrasive powders such as those from cement vertical mills, slag powder, and fly ash, significantly reducing maintenance costs.
Flow Control Gate Valves | Precision Feeding, Stable Regulation & High-Capacity Discharge Solutions
Our Flow Control Gate Valves are engineered for precise and reliable bulk solid and powder feeding in the cement industry. From fine-tuning at homogenization silo outlets to silo bottom discharge and air slide conveying, all the way to continuous operations like ship loading, the B-Series offers a complete flow regulation solution. Featuring flanged connections, the range includes cost-effective models with robust sealing for small to medium plants, as well as advanced modular designs that allow for quick actuator replacement and support both pneumatic and electric operation, meeting the demanding requirements of processes from raw material dosing to finished product dispatch.
Gradually adjust the cement raw material powder and apply at the outlet of the homogenization tank.Enables smooth and controlled feeding of raw meal powder from the homogenization silo to the raw mill, ensuring stable mill operation and optimal grinding efficiency.
Flange connection form, suitable for scenarios such as bottom discharge of the silo and air slide chute transportation.Its standard flanged connection makes it a versatile and reliable choice for sealing the discharge point between cement silos and conveying equipment.
Control the discharge flow of raw materials/sintered materials, with a capacity of up to 50-100 tons per hour.Engineered for high-capacity, continuous metered feeding in demanding applications such as raw material batching stations, ensuring consistent and uninterrupted process flow.
With a rigid sealing structure and it offers outstanding cost-effectiveness in small and medium-sized cement plants.Offers a cost-effective solution for both precise throttling and tight shut-off at silo side outlets or bulk loading spouts in small to medium-sized plants.
The modular design enables quick replacement of the actuators and is compatible with both pneumatic and electric modes.The flexibility of dual pneumatic/electric actuation and a modular quick-change design drastically reduce maintenance downtime and spare parts costs in automated dosing systems.
Capacity 200 tons per hour, meeting the continuous operation requirements such as ship loading at the port.Designed for high-throughput, heavy-duty applications like ship loaders and dispatch stations, delivering reliable shut-off and exceptional durability.
Industrial Lump Breakers | Crushing Solutions for Blockage & Hard Materials
Our Lump Breakers are designed to handle material caking and large agglomerates formed due to moisture absorption in industrial processes. They are key equipment for ensuring unimpeded flow in powder and bulk solid conveying systems. The full product range, from compact lump breakersto heavy-duty models for high-hardness materials, effectively solves problems like silo outlet blockages and pipe bridging, restoring material flow. Featuring low flow resistance and low energy consumption designs for efficient operation, they can be selected for complex conditions such as high temperatures and large flow rates. They are widely used in the material pre-processing stages of industries like cement, chemicals, metallurgy, and environmental protection.
Small in size and light in weight, suitable for scenarios with limited space.Can be directly installed at the inlet of small hoppers or screw feeders to solve material caking issues in space-restricted areas.
When lump breaker is fully opened, the fluid resistance is low.The unique full-bore design offers minimal flow resistance when open, preserving normal system conveying capacity, making it ideal for pneumatic conveying lines.
Low energy consumption, suitable for energy-saving needs.The optimized cutter disc and drive system ensure effective crushing while maintaining low-power operation, reducing long-term operating costs.
Requires higher power drive (above 1.5kW), suitable for larger flow requirements.Equipped with a powerful drive, it can handle sticky, moist materials or severely compacted lumps, meeting the continuous unblocking needs of large silos.
Suitable for more complex conditions, such as high temperature and high flow scenarios.Constructed with heat-resistant materials and special seals, it can handle lump breaking at dryer outlets or in high-temperature process stages.
Suitable for high-hardness materials , with compressive strength up to 320 MPa.The cutters are made of special alloy steel, capable of crushing materials with extremely high compressive strength like sintered ore and clinker, preventing damage to downstream equipment.
Excellent crushing effect, superior wear resistance, long service life.Key crushing components feature replaceable wear-resistant liners, designed for highly abrasive materials (e.g., slag), significantly extending maintenance intervals.
Precise control, prompt response, prevention of pipe blockage and corrosion, etc.Can be interlocked with level sensors or pressure transmitters for automatic start/stop, intelligently preventing blockages. It is the preferred choice for material handling systems in smart factories.
Industrial Slide Gate Valves | Reliable Shut-off for Bulk Solids & Powders
Our Slide Gate Valves are engineered for reliable shut-off and flow diversion in powder and bulk solid handling systems. Available in electric, pneumatic, manual, and electro-hydraulic actuation types to meet diverse needs, from simple manual operation to fully automated DCS control. Featuring a low-torque design for easy operation and a rigid seal structure for tight shut-off and long service life even with highly abrasive materials like cement and mineral powders. They are the standard choice for key points such as silo bottoms, screw conveyor inlets/outlets, and dust collector discharges in industries like cement, power, and metallurgy.
The electric device is equipped with a torque control mechanism and supports manual emergency switching.Integrated with limit and overload protection, it enables precise remote automated control, making it ideal for centralized batching systems.
The handwheel is combined with a trapezoidal threaded valve stem, resulting in an opening and closing torque as low as 50N·m.Simple and reliable in design with minimal maintenance cost, suitable for infrequently operated locations or as a manual bypass for automated valves.
Supporting 4-20mA signal control, and can be linked with the DCS system to achieve remote opening and closing.Offers fast response and supports 4-20mA analog signals for direct integration with PLC or DCS systems, enabling interlocked control with level sensors and scales.
The Hydraulic-electric system has good stability and is highly reliable and stable for the long term using.Delivers high thrust and smooth operation, especially suited for heavy-duty applications requiring high torque and frequent cycling, or where space constraints limit large pneumatic cylinder installation.
Guaranteed Quality at A Better Price
By choosing our discharge valve, you will enjoy the advantage of factory direct sales without middleman markup, which makes the price more competitive. At the same time, we strictly control every production process to ensure that our products meet high quality standards. In addition we also provide you with comprehensive after-sales service, so that you can buy with confidence and use with peace of mind.
Cement Plant Valve Solutions | Combatting Abrasion, Heat & Downtime
We engineer specialized valve solutions for the cement industry’s most demanding processes. From raw material handling to clinker cooling and cement dispatch, our valves are built to withstand extreme abrasion, high temperatures, and continuous dust exposure, ensuring reliable sealing and uninterrupted flow to maximize your plant’s productivity and reduce total cost of ownership.
| Solution Area | Core Challenge | Recommended Valve Solution | Key Features & Value |
|---|---|---|---|
| Raw Meal Preparation | Highly abrasive raw meal powder; prone to clogging; requires precise, high-volume feeding from blending silos. | 1. Vertical/Raw Mill Outlet: Wear-Resistant Ceramic-Lined Rotary Valve 2. Homogenization Silo Discharge: High-Capacity Flow Control Gate Valve (with anti-clogging device) |
• 2-3x longer wear life • Enables precise, stable feeding for optimal mill efficiency |
| Clinker Burning Line | Extremely high material temperature (up to 450°C); hard clinker lumps can damage downstream equipment. | 1. Preheater/Kiln Inlet: High-Temperature Double Flap Valve 2. Cooler Outlet: Heavy-Duty Clinker Crusher Valve (with special alloy cutters) |
• Reliable sealing at high temperatures • Effectively breaks clinker lumps to protect conveying systems |
| Cement Grinding & Dispatch | Requires fast, dust-free truck/railcar loading; silo discharge needs accurate metering and tight shut-off. | 1. Cement Silo Bottom: Low-Torque Slide Gate Valve + Precision Flow Control Valve 2. Truck Loader Interface: Quick-Actuating Pneumatic Valve (with dust containment skirt) |
• Enables dust-free loading, meeting environmental standards • Accurate metering; modular design increases maintenance efficiency by 50% |
| Plant-Wide Value | High wear leads to frequent downtime; complex spare parts management. | Valves feature chromium carbide overlay or ceramic liners on critical wear parts; compatible with DCS/PLC integration. | • Overall failure rate below 0.5% • Remote monitoring & alerts enable predictive maintenance |
Industry Solutions | Tailored Valve Systems for Your Sector
We don‘t just sell valves—we provide engineered flow control solutions that address the unique material handling challenges within your industry. Our expertise lies in understanding the specific abrasion, corrosion, temperature, and pressure demands of different processes to recommend and supply the optimal valve package, ensuring maximum uptime, safety, and operational efficiency for your plant.
Featured Industry Applications
• Cement & Building Materials
◦ Core Challenges: Extreme abrasion from clinker and raw meal, high temperatures, and continuous dust exposure.
◦ Our Solution: A full range of wear-resistant discharge valves, heavy-duty slide gates with hardened seals, and high-temperature rotary valves for kiln feed and cooler applications. We ensure reliable flow from the quarry crusher to the cement silo.
◦ Key Valves: Abrasion-Resistant Double Flap Valves, Clinker Crusher Valves, Silo Discharge Gates.
• Mining & Minerals Processing
◦ Core Challenges: Handling high-density, coarse, and highly abrasive ores, slurries, and tailings, often in remote locations requiring robust, low-maintenance equipment.
◦ Our Solution: Heavy-duty knife gate valves for slurry isolation, impact-resistant lump breakers for oversized material, and severe-service slide gates built to withstand relentless wear in conveyor transfer points and hopper discharge.
◦ Key Valves: Knife Gate Valves for Slurry, High-Pressure Slurry Valves, Mine Hopper Discharge Gates.
• Chemical & Petrochemical
◦ Core Challenges: Corrosive media, stringent leakage prevention requirements, and handling of toxic or hazardous powders and granules.
◦ Our Solution: Stainless steel and alloy rotary valves, zero-leakage double flap valves with advanced sealing technology, and explosion-proof (ATEX/Ex-Proof) actuated valves for safe operation in volatile atmospheres.
◦ Key Valves: Corrosion-Resistant Rotary Feeders, Explosion-Proof Slide Gates, Sealed Powder Valves.
• Food, Pharma & Plastics
◦ Core Challenges: Maintaining hygienic (sanitary) standards, preventing contamination, and handling delicate or cohesive food-grade powders, grains, and pellets.
◦ Our Solution: Polished stainless steel slide gates and rotary valves with easy-clean designs, FDA-compliant seals, and gentle-acting butterfly or flap valves to prevent product degradation.
◦ Key Valves: Sanitary Slide Gates, Food-Grade Rotary Airlocks, Dust-Tight Butterfly Valves.
• Power Generation (Coal, Biomass, Fly Ash)
◦ Core Challenges: Managing fly ash, bottom ash, and biomass fuel which are highly abrasive and can cause severe pipeline wear and clogging.
◦ Our Solution: Dedicated fly ash handling valves, including abrasion-resistant ceramic-lined valves and high-temperature isolation gates for boiler feed systems. Our lump breakersprevent clogging in storage silos.
◦ Key Valves: Fly Ash Rotary Valves, Ceramic-Lined Slide Gates, Biomass Fuel Feed Valves.
How We Partner With You
1. Process Analysis: We review your material characteristics (size, moisture, abrasiveness) and system layout.
2. Product Selection: We match you with the right valve type, material of construction (cast iron, carbon steel, stainless steel), and actuation package.
3. Performance Guarantee: Our solutions are built for long service life and reduced total cost of ownership, minimizing downtime and maintenance.
Ready to solve your specific flow control challenge? Contact our engineering team today for a free application review.
Discharge Valve Application Cases
The discharge valve is widely used in industrial production, mainly for the stable control and sealing isolation of the material transportation system.
Different types of discharge valves are suitable for various scenarios based on their characteristics such as wear resistance and sealing performance.
The silo discharge valve in the fields of cement, metallurgy and chemical industry performs the dual functions of precise discharge and sealing and dust prevention. Darko’s bottom system has developed a three-level modular combination of slide gate valves, rotary valves and flow control valves, meeting the requirements of the ISO 15378:2025 sealing standard.
The dust collector discharge valve, as the core control component of the pneumatic ash conveying system, mainly fulfills the dual functions of dust emission and system sealing. In scenarios such as the purification of blast furnace gas in steel plants and the dust removal at the end of cement kilns, it is often used in series with double flap valves to form a two-level sealing system for protection.
The discharge valve is adopted as the lock wind device at the inlet of the vertical mill. The quantitative feeding is achieved through the rotation of the impeller, while blocking the exchange of internal and external air pressures in the system.
The discharge valve in the pneumatic conveying system is the core component that ensures the stable operation of the system. Its core function is to achieve gas sealing and continuous feeding.
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More Information
If you would like to know more about our discharge valve, please feel free to contact our sales team. We will provide you with detailed information, product demonstrations and customised solutions.
It is necessary to clearly define the requirements for material particle size, temperature, corrosiveness and process flow.
Under normal conditions, carbon steel or 304 stainless steel is used; in highly corrosive environments, plastic lining or Hastelloy alloy is adopted.
V=V1×N×60×(1−G)×K
V: Discharge capacity volume (m³/h);
V 1: Volume per revolution of the rotor (L/rev or m³/rev);
N: Rotational speed (rpm);
G: Material density (T/m³) or discharge percentage (in some formulas, it is the filling rate);
K: Correction factor (typically 0.7 – 0.8) or bulk density (T/m³).
Yes! Our discharge valves are highly customizable.
Delivery times vary depending on the order quantity and customization options. Typically, standard orders are shipped within 10-15 business days, while customized configurations may take longer.
Yes, we provide comprehensive support, including user manuals, selection guides, configuration videos even Free on-site assistance.