Common types of industrial dust collectors and characteristics of wet explosion-proof dust collectors

With the continuous expansion of the scale of industrial production, more and more attention has been paid to the dust control issues generated in processes such as cutting, grinding, polishing, crushing, conveying and mixing. Industrial dust may not only affect the workshop environment and equipment operation, but some combustible dust may also create a risk of combustion or explosion when it reaches a certain concentration and encounters an ignition source.

The dust collector is an important piece of equipment in the industrial dust control system. Different types of dust collectors have differences in working principles, applicable dust, processing efficiency and maintenance requirements. Reasonable selection should be made based on actual working conditions.

1. The main functions of industrial dust collectors

Industrial dust collectors collect dust-containing gases generated during the production process through dust hoods, air ducts, fans and purification equipment, and use gravity, inertia, centrifugal force, filtration or gas-liquid contact to separate particles.

1. Reduce the spread and deposition of dust in the production area.

2. Reduce the impact of dust on production equipment, pipelines and products.

3. Reduce the operating load of subsequent exhaust gas treatment equipment.

4. For combustible dust working conditions, use explosion-proof measures to reduce related safety risks.

2. Dry mechanical dust collector

Dry mechanical dust collector mainly uses the gravity, inertia or centrifugal force of particles to separate. Common equipment includes gravity settling chamber, inertial dust collector and cyclone dust collector.

This type of equipment has a relatively simple structure and is usually suitable for processing dry dust with higher concentration, larger particle size, and higher density. It can also be used as a pretreatment equipment at the front end of a bag dust collector or cartridge dust collector.

1. Gravity settling chamber: By expanding the air flow channel and reducing the flow rate, larger particles can settle under the action of gravity.

2. Inertial dust collector: By changing the direction of the air flow, the particles are separated from the air flow due to inertia.

3. Cyclone dust collector: Utilizes the centrifugal force generated by the rotating air flow to throw the particles toward the wall and into the ash hopper.

Dry mechanical dust collectors usually have limited processing capabilities for ultra-fine dust, and subsequent fine filtration equipment is required when emission requirements are high.

3. Bag and cartridge dust collectors

Bag dust collectors and cartridge dust collectors use fiber filter materials to intercept dust. They are suitable for processing a variety of dry industrial dusts and have good filtration capabilities for fine particles.

1. Large filter area, suitable for continuous production conditions.

2. The dust on the surface of the filter material can be removed by pulse injection.

3. Filter materials should be selected based on temperature, humidity, corrosiveness and dust properties.

4. For combustible dust, measures such as anti-static filter material, grounding, explosion venting or explosion-proofing should be provided.

4. Wet explosion-proof dust collector

Wet explosion-proof dust collector uses water bath, spray, water film or gas-liquid mixing to wet, condense and capture the dust particles with liquid, and then conduct centralized treatment through precipitation, sewage discharge or filtration.

The equipment is suitable for some working conditions that are accompanied by sparks, high-temperature particles, sticky dust or are prone to secondary dust. Common forms include spray scrubbers, impact wet dust collectors, venturi scrubbers and wet cyclone dust collectors.

5. Working process of wet explosion-proof dust collector

After the dust-containing gas enters the equipment, it first passes through the diversion, deflection or pre-separation area, so that larger particles and some high-temperature sparks are initially captured.

The air flow then comes into full contact with water or absorbent liquid. The dust particles are wetted and collide and agglomerate with the liquid droplets to form larger dust-containing droplets, which eventually enter the circulating water tank or sedimentation area.

The processed gas passes through the baffle or demister to reduce droplet entrainment and is discharged by the fan. Dust and sludge deposited in the water tank need to be cleaned and discharged regularly.

6. Main features of wet dust removal

1. Reduce secondary dust: dust is not easily resuspended after entering the liquid phase.

2. Able to cool sparks: Water bath or spray liquid can cool some high-temperature particles and sparks.

3. Suitable for some sticky dust: It can reduce the problem of ordinary filter bags or filter cartridges being blocked by sticky substances.

4. Simultaneous cooling: suitable for cooling and pretreatment of some high-temperature dusty gases.

5. Can handle some water-soluble components: After configuring the absorbing liquid according to the properties of the pollutants, a certain degree of absorption or neutralization can be achieved.

7. Applicable scenarios of wet explosion-proof dust collector

1. Grinding, polishing and abrasive belt processing of metal products.

2. Particles produced by grinders, cutting machines and extrusion equipment.

3. Some dust conditions accompanied by sparks, high-temperature particles or oil mist.

4. Part of the dust produced by casting, metallurgy and non-ferrous metal processing.

5. Some sticky dusts are not suitable for ordinary dry filtration.

8. Wet-type equipment is not suitable for all combustible dusts

Wet-type dust removal can reduce dust suspension and secondary dust, but it cannot be simply assumed that simply using water can completely avoid combustion or explosion.

Some metal dust may react with water and produce hydrogen gas or heat. For example, certain aluminum powders, magnesium powders and reactive metal dusts require special evaluation based on particle state, alloy composition and reaction characteristics.

For water-reactive dust, ordinary wet dust removal solutions must not be directly applied. Professionals should determine the appropriate liquid medium, explosion-proof structure and safety control measures.

9. Explosion-proof design requires systematic consideration

The wet explosion-proof dust collector is only a part of the dust explosion-proof system. The safe operation of the equipment also requires corresponding measures based on the dust explosion characteristics and the configuration of on-site hazardous areas.

1. The equipment box, air duct and metal parts must be reliably grounded.

2. Configure explosion-proof motors and electrical components that meet site requirements.

3. Set up liquid level, temperature, air volume and water pump operation monitoring.

4. Set up an interlock between the water pump and the fan to avoid running due to water shortage.

5. Configure pressure relief, explosion-proof or other protective measures based on risk assessment.

6. Discharge sewage regularly to avoid long-term accumulation of sludge and combustibles.

10. Parameters required for equipment selection

1. Dust name, composition, particle size, concentration and density.

2. Whether the dust is flammable, explosive or reactive with water.

3. Actual processing air volume and daily operating time.

4. Whether there are sparks, high temperature particles, oil mist or corrosive substances.

5. Exhaust gas temperature, humidity and on-site installation space.

6. Treatment conditions for wastewater, sludge and circulating fluid.

11. Precautions for operation and maintenance

1. Before starting the fan, make sure that the water pump, liquid level and spray system are operating normally.

2. Regularly check whether the nozzles, deflectors and mist eliminators are clogged.

3. Clean the circulating water tank, sedimentation area and sewage pipes regularly.

4. Check the fans, water pumps and valves for abnormal noise or leakage.

5. Regularly check grounding, electrical interlocks and alarm devices.

6. Timely replenish water, filter or discharge according to the status of circulating fluid and sludge.

Different types of dust collectors have their own applicable scopes. Wet explosion-proof dust collector is suitable for some working conditions of sparks, sticky dust and combustible dust, but the equipment selection must be specially designed based on the dust explosion characteristics, water reactivity, processing air volume and on-site safety requirements.