A quantitative coal feede is a device that transports raw coal to a coal mill or boiler at a certain flow rate, evenly and continuously. We can know that the amount of coal transported by the coal feeder is uniform and a certain amount. However, other transportation methods such as manual coal shoveling and belt transportation cannot uniformly provide coal to mills and boilers, and the amount of coal transported is unknown. The coal feeder can continuously and accurately feed coal, and the coal quantity is known.
Taking coal combustion for power generation in a thermal power plant boiler as an example, the use of a coal feeder can stably control the overheating temperature, reheating temperature, and pressure temperature, making the interval of coal combustion and the proportion of air volume more appropriate. This not only saves coal consumption, but also maintains the thermal power within a certain range. So the function of the coal feeder is simply to make the coal supply continuous, controllable, and uniform.There are various types of coal feeders, including disc type coal feeders, belt type coal feeders, belt gravity type coal feeders, scraper type coal feeders, and electromagnetic vibration type coal feeders.
However, different types of coal feeders are suitable for different types of coal and different locations:
The disc type coal feeder has a small volume and good sealing, mainly suitable for transporting loose and non cohesive coal; Belt type coal feeders are suitable for long-distance transportation, but coal with excessive viscosity is not suitable for transportation. According to structural characteristics and working principles, there are two types: volumetric and gravitational.
The coal in the coal storage bin enters the coal feeder through the coal gate, and is continuously and evenly transported to the coal mill through the conveyor measuring tape inside the coal feeder. An electronic weighing device is installed below the conveyor measuring tape, which is mainly composed of high-precision electronic belt scales. The weighing sensor generates an electrical signal proportional to the weight of the coal and the belt speed signal detected by the speed sensor, which is also sent to the integrator, The instantaneous flow rate and cumulative quantity are obtained after accumulation.
The widely used volumetric coal feeders include disc type coal feeders and scraper type coal feeders.
2. The disc coal feeder uses the adjustment of the disc speed and the position of the inner sleeve to change the coal feeding amount on the disc; Adjust the scraper angle to change the amount of coal scraped. It has the advantages of compact structure and good sealing, but it is prone to coal blockage and slipping when encountering high moisture coal.
3. The scraper type coal feeder adjusts the coal feeding amount by adjusting the speed of the coal feeder and adjusting the position of the gate. It can be made into a fully enclosed type, with wide applicability for coal types, but it occupies a large area. During operation, when the coal is compacted, the scraper sometimes floats, which is easy to be stuck by wooden or stone blocks in the coal and break the coal.
4. Belt electronic gravity coal feeder is a type of gravity coal feeder. It consists of two weighing idlers installed inside the coal feeder shell, which form a weighing span with the belt. A precise weighing sensor is installed on one of the weighing rollers in the weighing span, which can generate a load signal of coal conveying weight per unit belt length. A photoelectric speed sensor is installed on the active pulley to generate a speed signal.
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