There are generally four commonly used methods to control the smoke and dust in the factory workshop: local dust removal scheme, mixed ventilation scheme, displacement ventilation scheme and blow-suction ventilation scheme. In the welding workshop, large-scale welding, grinding and other processes that are difficult to use point-to-point to collect dust, the overall blow-suction ventilation scheme is used more.

The overall blowing and suction ventilation and dust removal scheme combines the blowing air and the inhaling air to work together, that is, setting a blowing port on the opposite side of the inhaling port to form a blowing air flow, and use it to induce and control the polluted air flow. This dust capture method is suitable for occasions where the distance is too large, and the suction port alone cannot effectively suck the polluted airflow.

Analysis of the advantages of the blow-suction ventilation and dust removal scheme:

Good performance: Generally, the air speed of the air collecting hood decreases rapidly with the distance, and the control of the air speed at the pollution source is usually solved only by increasing the exhaust air volume, and its energy utilization is very low. The blowing-suction type hood mainly uses the blowing jet to increase the control wind speed outside the pollution source, and the speed distribution is relatively concentrated, so it can effectively improve this low-efficiency situation and improve the effective utilization.

The effect is relatively stable: the general gas collecting hood uses the airflow generated by the process itself to collect the polluted gas, but this airflow is unstable and will be disturbed by other airflows, and it is easy to escape the hood. The blowing air flow of the blow-suction hood can be designed according to the needs of the process, so as to keep the operation more stable.

It is more suitable for large-area and strong-diffusion pollution sources: generally, it is difficult to control the pollution sources with large area and rapid diffusion by the gas collecting hood. The blow-suction type gas collecting hood can expand the control range and improve the control speed by taking advantage of its long injection process.

Good pollution control effect: Because the blow-suction ventilation relies on the combined work of blowing and suction flow to control and transport harmful substances, it has the characteristics of small air volume, good pollution control effect, strong anti-interference ability, and does not affect the process operation.

Good fume capture effect: The blowing and suction ventilation device is placed in the area with the maximum concentration of welding fume, which can maximally remove and purify the welding fume accumulated at the "appropriate height" in the workshop.

The installation method of the equipment is simple: due to the large number of pipelines and traffic in the welding workshop, there are certain difficulties in laying horizontal air ducts above the welding area and installing the dust hood.