Keeping the safer workplace environments is the most concerned of workshop owners and thankful to the dust collector systems, the job of protecting workers’ health from dust and air pollution is done better and better.
However, how does a dust collector work? This system is designed for collecting the high-volume dust loads and other impurities from air and gas in industrial and commercial processes.
The system has 3 main parts including a main dust collector, ambient air purifier and a ductwork which is used to connect with other parts. In general, there are five types of dust collector systems used in many industrial processes.
Inertial separator works based on the combination of forces including centrifugal, gravitational, and inertial. These forces remove dust from gas stream, and then the gravity will transfer the separated dust into a hopper, where keeps separated dust as a temporary place. There are three primary types of inertial separators including settling chambers, baffle chambers and centrifugal collectors.
Settling chambers separate solid dust by using the force of gravity.
At first, the gas stream will get into a chamber where the velocity of gas is decreased, and then from the chamber the large particles will be dropped out of the gas and the separated particles is moved into hoppers.
However, settling chambers aren’t popularly used as primary dust collector due to their large space requirements but low efficiency, so they are often incorporated in with more effective dust collectors.
Baffle chamber is designed with a fixed baffle plate that can change the gas stream into another direction in order to help the larger particles not to follow the gas stream but continue to settle in the needed space. Plus, like settling chambers, baffle chambers are rarely used as primary dust collectors.
Centrifugal collector works by using the combination of forces including centrifugal, buoyant and drag force. When the dust air enter the cyclone which is regulated at a controlled speed to allow the heavier particles to be separated from the main stream and then drop to the bottom of cyclone and then the separated dust are collected in hoppers.
Fabric collector, also known as baghouses, separates particles from gas stream by using filtration.
At first, dusty air enters through the filtration (fabric bags) often made of woven or felted cotton, synthetic, or glass-fiber material and designed as a tube or an envelope shape and then the filtration starts to work.
Plus, of all the dust collector systems, fabric collector works as the most effective one, which can achieve more than 99% of efficiency.
Wet scrubber uses the liquid – water in the process of handling dust, which passes through many parts of the system of a wet scrubber including a scrubbing vessel, ductwork and fan system, mist eliminator, pumping (and possible recycle system), spent scrubbing liquid treatment and an exhaust stack.
Due to the high efficiency of the wet scrubbers, they are commonly preferred to reduce the pollutant at petroleum refineries, acid manufacturing plants, and steel making.
Plus, the wet scrubber also comes in a variety of types such as chemical scrubbers / gas scrubbers, particulate scrubbers / venturi scrubbers, ammonia Scrubbers, chlorine Scrubbers, particulate / dust Scrubbers and sulfuric acid scrubbers.
However, all of the types can be described in three basic configurations.
Gas-humidification – this process will pile up the fine particles and increase the bulk to allow the collection to be handled easier.
Gas-liquid contact – the particle and droplet will pass through four primary mechanisms:
Inertial impaction – the process will work based on the inertia, on the path of a dust-laden gas stream, dust particles will be moved in a straight path, hit the droplets and become encapsulated.
Interception – the gas stream will carry the finer particles directly, brush against the droplets and adhere to the droplets.
Diffusion – the dust particles are deposited on the droplets’ surfaces by diffusion.
Condensation nucleation – the moisture will be condensed on the surface of dust particles, which increase as sizes of the particles in order to help the collection occur easier.
Gas-liquid separation – when the droplets contact to dust particles and form agglomerates, they will be later placed in a collector when being larger enough.
Unlike other dust collectors, the unit collector handles the dust at its source. The system consists of two parts including a fan and some forms of dust collector and this system is designed to help dust particles are isolated and portable.
There are two types of unit collectors including fabric collectors used for fine dust, and cyclone collectors used for coarse dust.
In addition, due to the high efficiency of dust collection and the ability of continuing exhaust airflow between cleaning and cycles, fabric collectors are commonly used in mineral processing operations while cyclone dust is preferred to be installed in the workshops of woodworking and metal grinding.
As the name mentioned, electrostatic precipitators work by using the electrostatic forces. The system is designed with two main parts including discharge wires and collecting plates.
Also, the Ionization occurs around the discharge wires to supply ions, so when the dusty gas flows between discharge wires and collecting plates, dust particles are charged and then the charged particles will be collected in the collecting plates and the air is later purified.
In addition, the particles on the collecting plates are removed by rapping or vibrating the collecting electrodes, and then will be washed off with water and removed from a hopper.