Dust Extraction System
Dust Extraction System
An effective dust collection system offered to enhance the quality of air released from industrial and commercial processes by collecting dust and other impurities from air or gas. Designed to handle high-volume dust loads, a dust collector system consists of a blower, dust filter, a filter-cleaning system, and a dust receptacle or dust removal system. It is distinguished from air cleaners, which use disposable filters to remove dust.
Dust collection systems work on the basic formula of capture, convey and collect.
First, the dust must be captured or extracted. This is accomplished with devices such as capture hoods to catch dust at its source of origin.
Second, the dust must be conveyed. This is done via a ducting system, properly sized and manifolded to maintain a consistent minimum air velocity required to keep the dust in suspension for conveyance to the collection device.
Finally, the dust is collected. This is done via a variety of means, depending on the application and the dust being handled.
1. Capture: We CARAMET Design the Hoods as per ACGIH Standard. Our Ergonomically designed hoods extract the dust emitting to the work environment through the different types of manufacturing process. We extract the dust away from the operator breathing zone without hindrance the man and material movement in the manufacturing process. We design the best suitable type of hood to suit the process, to achieve economized efficient extraction. The suitable capture velocity will be maintained to achieve an effective Dust Extraction System.
We consider three major factors while designing the effective Capture Hoods.
- 1.1 Contaminant Characteristics
- 1.2 Hood Type
- 1.3 Capture Velocity.
1.1 Contaminant Characteristic:
- 1.1.1 Inertial Effects: Gases, vapors, and fumes will not exhibit significant inertial effects. Also, fine dust particles, 20 microns or less in diameter (which includes respirable particles), will not exhibit significant inertial effects. These materials will move solely with respect to the air in which they are mixed. In such cases, the hood needs to generate an air flow pattern and capture velocity sufficient to control the motion of the contaminant-laden air plus extraneous air currents caused by room cross-drafts, vehicular traffic, etc.
- 1.1.2 Effective Specific Gravity: Frequently, the location of exhaust hoods is mistakenly based on a supposition that the contaminant is “heavier than air” or “lighter than air.” in most health hazard applications, this criterion is of little value (see Figure 3-2). Hazardous fine dust particles, fumes, vapors, and gases are truly airborne, following air currents, and are not subject to appreciable motion either upward or downward because of their own density. Normal air movement will assure an even mixture of these contaminants. Exception to these observations may occur with very hot or very cold operations or where a contaminant is generated at very high levels and control is achieved before the contaminant becomes diluted.
- 1.1.3 Wake Effects: As air flows around an object, a phenomenon known as “boundary layer separation” occurs. This results in the formation of a turbulent wake on the downstream side of the object similar to what is observed as a ship moves through the water. The wake is a region of vigorous mixing and re-circulation. If the object in question is a person who is working with, or close to, a contaminant-generating source, re-circulation of the contaminant into the breathing zone is likely. An important consideration in the design of ventilation for contaminant control is minimizing this wake around the human body and, to the extent possible, keeping contaminant sources out of these recirculating regions
1.2 Hoods Type: Hoods may be of a wide range of physical configurations but can be grouped into two general categories: enclosing and exterior. The type of hood to be used will be dependent on the physical characteristics of the process equipment, the contaminant generation mechanism, and the operator/equipment interface
1.2.1 Enclosing Hood: Enclosing hoods are those which completely or partially enclose the process or contaminant generation point. A complete enclosure would be a laboratory glove box or similar type of enclosure where only minimal openings exist. A partial enclosure would be a laboratory hood or paint spray booth. An inward flow of air through the enclosure opening will contain the contaminant within the enclosure and prevent its escape into the work environment. The enclosing hood is preferred wherever the process configuration and operation will permit. If complete enclosure is not feasible, partial enclosure should be used to the maximum extent possible
1.2.2 Exterior Hood: Exterior hoods are those which are located adjacent to an emission source without enclosing it. Examples of exterior hoods are slots along the edge of the tank or a rectangular opening on a welding table. Where the contaminant is a gas, vapor, or fine particulate and is not emitted with any significant velocity, the hood orientation is not critical. However, if the contaminant contains large particulates which are emitted with a significant velocity, the hood should be located in the path of the emission.
1.3 Capture Velocity: The minimum hood-induced air velocity necessary to capture and convey the contaminant into the hood is referred to as capture velocity. This velocity will be a result of the hood air flow rate and hood configuration. Exceptionally high air flow hoods (example, large foundry side-draft shakeout hoods) may require less air flow than would be indicated by the capture velocity values recommended for small hoods. This phenomenon may be ascribed to: The presence of a large air mass moving into the hood The fact that the contaminant is under the influence of the hood for a much longer time than is the case with small hoods.
2. Conveying: Dust Extraction systems are intended to carry dust, a minimum conveying velocity is necessary to ensure that the dust will not settle in the duct. Also, when a system is installed in a quiet area, it may be necessary to keep velocities below some maximum to avoid excessive duct noise. A duct of the wrong size can lead to material settling in the duct system and clogging it. We design and manufacture ducting as per ACGIH and IS 655 standard. We have facilities to manufacture ducting in different type Material of Construction such as Mild Steel, Stainless Steel (SS 304, SS 304L, SS 316, SS 316L, SS 316 Ti, SS 310 .. etc), Polypropylene(PP), PP+FRP, PVC+FRP, CPVC+FRP to suite to operation requirement.
3. Collect: This is done via a variety of means, depending on the application and the dust being handled. It can be as simple as a basic pass-through filter, a cyclonic separator, or an impingement baffle. It can also be as complex as an electrostatic precipitator, a multistage Bag-filter/Dust Collector, or a chemically treated wet scrubber or stripping tower.
Cyclone Separator
A cyclone separator is an apparatus for the separation, by centrifugal means, of fine particles suspended in air or gas. A high speed rotating (air) flow is established within a cylindrical or conical container called a cyclone. Air flows in a helical pattern, beginning at the top (wide end) of the cyclone and ending at the bottom (narrow) end before exiting the cyclone in a straight stream through the center of the cyclone and out the top. Larger (denser) particles in the rotating stream have too much inertia to follow the tight curve of the stream, and strike the outside wall, then falling to the bottom of the cyclone where they can be removed. In a conical system, as the rotating flow moves towards the narrow end of the cyclone, the rotational radius of the stream is reduced, thus separating smaller and smaller particles. The cyclone geometry, together with flow rate, defines the cut point of the cyclone. This is the size of particle that will be removed from the stream with 50% efficiency. Particles larger than the cut point will be removed with a greater efficiency and smaller particles with a lower efficiency
Bag-Filter/Dust Collector
Commonly known as bag houses, fabric collectors use filtration to separate dust particulates from dusty gases. They are one of the most efficient and cost effective types of dust collectors available and can achieve a collection efficiency of more than 99% for very fine particulates. Dust-laden gases enter the bag house and pass through fabric bags that act as filters. The bags can be of woven or felted cotton, synthetic, or glass-fiber material in either a tube or envelope shape. Bag houses are characterized by their cleaning method.
Industrial Application
Over a 2 Decades Caramet executed number of Dust collection systems for Paint Industries. Wherein many of Systems are based on Aspiration system and Point exhaust system. The Paint dust has different physical and chemical characters which need to be considering while designing system. While extraction of Dust from Pain Manufacturing process needs special attention to designs and achieve proper capture velocity to avoid Product Loss and Protecting Human breathing Zone for Safe working conditions.
Some are required to design with Unique care of cross contamination and easy separation as Bag filter Dust Collector. Caramet has wide range of Filter bags to suit every type of Paint dust and clean separation
Caramet takes upmost care in designing Dust collection systems in Food Industries. Top most Hygiene and food contamination while collection can be Taken care of. Dust particles physical and chemical characters make choice of Collection methodology, Selection of Capture velocity and View of reuse of collected Dust. Some of Dust collection systems are compiling ATEX Certifications.
Caramet has developed an effective Dust collection system for abrasive and erosion resisted dust collection systems. The separation with anti static treatment, High Temperature separation ranging up to 1000’c is proven Track record. Selection criteria for Duct, Hood, Dampers and Dust collectors MOC is USP for Caramet Design Dust collection systems
Caramet has well versed experience in power plants process and equipment’s and have hands on experience in design dust collection system for the same. The dust and gasses handling in Anti-static and nonhazardous way is well treated by Caramet
CARAMET has wide range of installations where in right from Toxic dust to flammable dust handle with maintaining TLV values in flashpoint applications. Dust collected separated and disposed of with intense care to protect work as well as outside environment. Caramet designed dust extraction systems for Mixers, Grinders, Weighing, Blending, bagging, Packaging, Coating pans etc.
Caramet has designed and successful in high temperature up to 900 degree C, heavy dust load in Boiler and DG set stacks . Wherein improved norms of 30 mg/N Cu. Meter Dust emission is well achieved and proven. Use of ceramic, Nomax and Unifrax Filter Bags helped to achieve these results.
In case of Metal industries right from any size of particle from particle size distribution to any abrasive dust to spark proof applications handled by Caramet. Use of wear resistant aprons to plates for better life of Dust collection system is applied with. Dust extractions hoods are designed as per norms set by ACGIH for various Metal working operations. Same and easy removal with sturdy design calls for repetitive Projects and expansions. Caramet has designed Dust Extraction system for Metal Working processes like Production grinding, Scratch brushing, Abrasive cut off, Buffing, Tool room, Cast Iron machining etc
Cement Industries produce cement kiln dust consisting ash, particulate matter, calcium carbonates, halides, volatile chemicals, alkalis, sulphates during the manufacturing of clinker. Right from pay loaders dumping material on ground hoppers to different material handling techniques like Belt, slat and screw conveyors, Bucket Elevators, Vibro screens, Clinkers, Lime stone baking area every operations has profuse dust emission. Caramet used there well versed experience to design proper Enclosure systems for various operations, Hoods to suit specific equipment’s. Selection of proper capture and conveying velocity are some of USP’s of CARAMET dust extraction systems. Huge dust quantum has been handled and reused back as product additives’. Caramet designed an effective Dust extraction for Various applications of Cement industries like Material Handling, Dryers, Kilns, Rock Dryers, Cement Kiln, Cement grinding, Cement Clinker Cooler etc
Caramet explore the opportunity in many Fertilizer industries to handle hazardous to corrosive dust with hygroscopic nature as unique threat. We have handled area of raw material charging, mixing byproduct emission to finish product store and packing. The expertise in choosing right capture velocities, addition or deletion of bleed-in air and achievement of outlet as well as work environment emission is proven track record of Caramet installed systems. Caramet designed an effective dust extraction system for Bagging machines, Belt Conveyors, Bucket Elevators, different transfer points..
Caramet designed an effective dust extraction systems for Refinery and petrochemicals process like Bagging, Flakers, Boilers, Heaters, melting furnaces etc. The dust generation during raw material handling to charging process and at stage of final bagging station at Jumbo as well small packs call for an effective dust extraction system. Caramet worked hand in hand with well know bagging and packaging industry to design system suitable for their operations. The installed system in various Refinery and Petrochemical industry certifies our statement of qualifications. The hygroscopic to abrasive all characters are well considered in selection of conveying velocities and right kind of MOCs.
Caramet has developed unique and safe separation system for Coal handling. The process where dust emitting to environment like Loading and unloading points, Belt conveyors, transfer points, Coal bunkers, crushing area. The physical and chemical characters of different types of coal dust in addition to that presence of flameable gasses in stream and coal dust as easily ignitable requires topmost care in design to avoid Fire Hazard, Selection of specific filter fabric and Bags design to play major role. Also can velocities and casing construction with safety devices ensure an effective collection and separation of Dust. We have proven track record of these supplied and working systems