Powder feeding equipment is vital. It conveys powder materials to the production process, accurately and evenly. Feeding equipment is vital to the silo system. It also conveys materials over short distances. Due to different purposes of use, it is also called a feeder, a feeder or a discharger. It is usually installed at the silo’s discharge port. It relies on the material’s gravity and the feeding equipment’s mechanism to discharge the silo’s material. It then feeds it continuously and evenly to the next equipment. The key role of the feeding equipment is to control the material flow. It must provide accurate feeding. In addition, when the feeder stops working, it can also play the role of locking the silo. Therefore, it is one of the indispensable equipment in the continuous production process.
Powder feeding equipment can be divided into many types. This is based on its application and working principles. The following are some common powder feeding equipment and their characteristics and applications:
Belt Feeder : Powder feeding equipment
Principle: The belt moves to transport the powder from the feed port to the discharge port. The belt feeder is a short belt conveyor. It can be installed horizontally or at an angle. It has some advantages over ordinary belt conveyors. The load-bearing section has more closely spaced supporting rollers. The unloaded section usually has no rollers. There are stationary railings on both sides of the belt. The belt speed is low.
Features: Long conveying distance, suitable for large flow of powder materials. It has a simple structure, low investment, and reliable operation. It needs low power during stable operation. It can adjust the feeding amount. We can automate and meter it. But it takes up a lot of space. The belt is easy to wear, so it is unsuitable for abrasive, high-temperature materials.
Application: Mainly for granular and small block materials. Rarely for medium-sized ones. Commonly used for the transportation of bulk materials such as coal, ore, sand and gravel.
Plate feeder : Powder feeding equipment
Apron feeders handle bulk materials or temps over 70°C. Like belt feeders, they can be mounted horizontally or at a steeper angle. The carrier plates are not mounted perpendicular to the chain but parallel to it. Light and medium apron feeders usually use roller chains on fixed tracks. Heavy apron feeders use fixed support rollers. The chain plates run along the rollers.
Features: Strong structure. It can withstand great pressure and impact. It can handle large, hot materials. It is highly reliable and ensures uniform feeding. The plate feeder has a complex design. It is heavy and costly to make. It is not suitable for powdered materials.
Application: Suitable for feeding and conveying large, abrasive, heavy, and hot materials.
Rotary Valve (Impeller) Feeders
Principle: The rotating blades move the powder from the feed port to the discharge port. The rotary valve (impeller) feeder has a shell. It can connect to the silo receiving device. An impeller rotor sits in the middle. The rotor is driven by a separate motor through a sprocket. When the rotor is stationary, the material cannot flow out. When the rotor rotates, the material can be discharged with the rotation of the rotor.
Features: simple structure, easy maintenance, suitable for powder materials with good fluidity.
Application: widely used in chemical, food, pharmaceutical and other industries.
Powder feeding equipment : Screw Feeder
Principle: The powder material is pushed forward by the rotation of the spiral blades. Screw feeders differ from general screw conveyors. Their pitch and length are smaller. They need no intermediate bearing. Their trough is a tube, not a U-shape like a conveyor’s. The spiral shaft has bearings at both ends outside the tube. The filling coefficient of the material is high, up to 0.8-0.9. There are two types of screw feeders: single-tube and double-tube.
Features: It can do continuous and precise feeding. It suits powdered materials of all sizes and viscosities. The screw feeder can seal. But, its parts wear quickly. So, it is only for non-brittle, low-abrasive, and free-flowing powders. It is mostly installed horizontally or at a 30-degree angle. It is 1-2m long and has a capacity of 2.5-3.0 m³/h. The feeding amount can be adjusted by changing the screw speed.
Use: For transport and metering in cement, coal, and fertilizer industries.
Disc Feeder
Disc feeder is a commonly used feeding equipment for powder and granular materials. It uses a rotating disc to convey the materials to the next process equipment. It does so evenly and continuously.
Working principle: The disc feeder is mainly composed of a motor, a reducer, a disc, a scraper and a hopper. When working, the motor drives the disc to rotate through the reducer. The material enters the disc’s surface from the hopper. The disc rotates to scrape the material evenly to the discharge port. This achieves continuous feeding.
Features: It has a simple structure. It is reliable and easy to adjust. The production capacity has a large range. It can control the amount of fed material with good accuracy. However, due to volume measurement, there is a 5% error. Also, the disc feeder has almost no conveying distance for the material. So, it is sometimes unsuitable due to layout issues.
Application: The disc feeder is for non-sticky materials. Their size must be 80mm or less. It is not suitable for powdery, highly fluid materials. They flow too easily.
Vibrating Feeder
Principle: The powder material is transported from the feed port to the discharge port through vibration. The vibrating feeder can be of two types: inertial and vibrating. This depends on the trough’s motion and the material. The inertial vibrating feeder uses inertial force. It keeps the material in contact with the trough’s bottom. It then slides along the trough’s bottom. In the vibrating feeder, the inertial force separates the material from the trough’s bottom. It is thrown upward, causing the material to “jump” in the trough. The difference between the two is as follows. The inertial trough’s vertical acceleration is less than free fall. The material is always in contact with the trough’s bottom. The trough vibrates faster than free fall. The material “jumps” at the bottom.
Features: compact, no mechanical wear. Suitable for fine, easy-to-agglomerate powders.
Application: widely used in mining, metallurgy, building materials and other industries.