Coal is a heterogeneous solid material. The coal sampling equipment we used in the thermal power plant at present is essentially a kind of equipment which integrates sampling and sample preparation. Under normal conditions, we will first collect a certain amount of samples from a batch of coal by automatic sampling system in the thermal power plant, and then we will make them into test samples which can represent the average quality level of the coal in this batch by reduction and division. These processes require very high technical level.
The following are the technical requirements of coal sampling machine for the thermal power plant. First of all, the sampling and the sample preparation must be representative, consistent with the accuracy of the relevant standards and trying to avoid systematic errors. Second, the sampling machine must be able to be operated safely and stably. The maintenance period is usually 1 to 2 years.
Working Principle and Structural Characteristics
The thermal power plant usually adopts the head cross belt sampling system. It consists of the head belt sampler, sample feeders, sample crusher, sample divider, sample collector, operation control system and the residue return system. During the sampling processes, the sampling head will perform full cross-section sampling on the head of the belt conveyor. The collected coal samples will be sent to the primary feeders by the coal chute. Then these coal samples will enter the coal crusher and sample divider in order to obtain the final test samples. After that, these test samples will be sent to the sample collector, and the remaining abandoned coal samples will enter the residual coal return system. All the equipment mentioned above are driven by the motor and the program control and manual control can both be realized.
Problems and Solutions in Operation
The motive power of the residual material lifting system is not strong enough
In the past, most of the residual material lifting system of coal sampling machine mainly through the chain bucket elevator to transport excess coal samples to the coal conveying belt. The lifting height of this system can reach about 10m, but because of the power problem of the equipment, a lot of remaining coal will be blocked at the bottom of the lifter. It will lead to tripping which is caused by overheating of the lifter. However, we can solve this problem by upgrading the hoist. We need to transform the chain bucket elevator into a belt bucket elevator, increase the power of the motor, thicken the coal falling tube, and increase the number of buckets to deal with this problem.
Coal Blockage Problem of Coal Falling Tube in the Coal Sampling System
Under normal circumstances, the coal falling tube between the coal crusher and the divider will be designed to be tilted. This kind of design is likely to lead to the accumulation of coal samples in the wall. Especially after the long-term operation of the coal sampling equipment, the coal falling tube is easy to be blocked by the accumulation of coal samples. In this case, we can adjust the falling tube to a vertical type to avoid the problem of sticking and clogging of coal samples.
In addition to these common problems, we may still encounter many other problems in the operation system of coal sampling machine, which we will discuss in details in Problems and Solutions of the Coal Sampling Machine Operation System in Thermal Power Plant (2). Hope this article will bring you some useful information.
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