The coal sample division machine is one of the devices in the coal sample preparation system. In the last article What is the Coal Sample Division Machine, we talked about the function and categories of it. We learned that the most commonly used division machine at present is the mechanical division machine. So next, we will continue with this topic and introduce four different types of mechanical coal sample division machine.
The Hammer Division Machine
The hammer division machine is mainly composed of a cutter, driving motor controlled by PLC, limit device, scraper, machine frame which equipped with a dust cover, sample discharge chute and some other components. Among them, the cutter is the core part of the hammer division machine. In the process of cutting coal samples, we should ensure that all samples have the same probability of entering the cutter to keep the representativeness. The movement direction of the cutter is perpendicular to the direction of the belt conveyor, and its motion track is arc-shaped. The diameter of the arc should be matched with the angle of the feeding chute of the belt feeder and keep enough distance from the conveyor belt. In addition, the opening size of the cutter should be more than 3 times of the nominal maximum particle size of the coal sample.
There is a scraper that equipped at the end of the cutter, which can prevent the belt from being damaged by the cutter. At the same time, the design of the division machine takes into full consideration of the situation that the cutter cannot effectively cut the coal on the belt conveyor due to the large distance. So the distance between the cutter and the belt conveyor is measured precisely. According to the requirements of the process flow, we can set the division times of the cutter and the quality standard of the final sample previously by the PLC system. In the case that the material flow is continuous and stable, the precision of the hammer division machine can be guaranteed, but in the case that the material flow is discontinuous or unstable due to various reasons, the precision of it will deviate, and the division ratio is relatively low.
The Rotary Division Machine
The rotary division machine consists of the transmission mechanism, cylinder, distributing device, rotary collector, vibrator and other components. Among them, transmission mechanism mainly includes motor, reducer, synchronous toothed belt, belt wheel, shaft and bearing seat. Bearing seat is a whole, the transmission shaft arm extends upward and the material receiver is installed on it. This structure makes the material dropping and receiving free from external factors, which is conducive to improving the precision. In addition, the motor, reducer and belt wheel are arranged at the lower end of the machine case so that their installation and assembly are easy and convenient.
The cone distributing device is arranged above the material receiver and it has the same axial direction with the receiver. The material will fall above the cone firstly and then falls evenly along the lower edge of the cone. In the material falling area, three material receiving hoppers are uniformly distributed, rotating at a certain speed. The receiving port is a fan-shaped around the rotation axis so that the materials distributed within the material falling area have the same probability of being collected. The rotary division machine adopts the cone distributing and fan-shaped receiving technology to achieve high precision, and this machine is generally used for the secondary division of coal sample.