During mechanical sampling, the coal will be lift by the spiral blade to the top of the sampling equipment, then a small part of coal will enter the collection hopper from the retention samples mouth, and the rest of the coal will be discharged back to the truck as discarded material. It is the process of coal falling from high places when abandoned coal is discharged back to truck. The dust generated in this process will be blown away by the wind and endanger the environment and human health. Therefore, it is necessary to design a spray dust suppression device which can move with the mechanized coal sampling equipment to control the dust suppression during the discharge process, so as to avoid the environmental pollution and the damage to human body.
The Current Situation of Mechanized Sampling Dust Suppression
At present, mechanized coal sampling equipment is widely used for coal sampling in thermal power plants, but it still lacks effective means of dust control. In GB /T 19494.1 — 2004 Mechanized Coal Sampling – Part 1: Sampling Methods, the general principles and precision of mechanized coal sampling, the establishment of sampling scheme, sampling method of moving coal flow, sampling method of stationary coal, packaging and labeling of coal samples and sampling report are stipulated particularly. It pays great attention to the standardization of sampling but does not involve the control of dust generation in the sampling process. The regulations in the GB/T 30730 — 2014 Technical Conditions of Coal Mechanical Sampling System attach importance to the technical performance of sampling equipment. Although it has the requirement that “the residual coal return system should be sealed without dust leakage”, but the sampling equipment is a kind of mobile device, it is difficult to realize the real sealing between the equipment and the coal transport vehicle. There will be a certain safety gap between the residual coal return equipment and the coal transport vehicle, from which the dust can float out.
In order to decrease the dust, we can take some simple but effective measures. For example, some mechanical sampling equipment usually reduces the safety gap between the residual coal return equipment and coal transport vehicles by installing a dustproof curtain. However, the dustproof curtain often in a state of fluttering so that it will be trapped easily by the sampling spiral, resulting in safety accidents. Therefore, the dustproof curtain cannot be too long.
In addition, we can also completely seal the area where the mechanical sampling device is installed. This method can effectively prevent dust pollution in the environment. But it needs a large investment, and the high dust concentration in the enclosed space will seriously affect the health of workers. Alternatively, we can apply spray dust suppression to the entire installation area of the mechanized sampling device. This method not only requires a large investment but also requires large amounts of spray water. What’s more, it will increase the water content of coal.
All the effective methods we mentioned above cannot solve the problem of dust leakage fundamentally. So the appearing of the follow-up spray dust suppression device greatly meets the need of many factories. It fundamentally solves the problem of dust leakage and greatly improves work efficiency.