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Bag Filter Dust Collector
Product Description:
A bag filter dust collector removes particulate from a dust-laden gas stream by forcing that gas through fabric filter bags, then cleans the bags in place with compressed-air pulses. The bags hang from a tube sheet, or slide in
through a side door: dust is captured on the outside of the fabric, clean gas leaves through the outlet, and the released dust falls into the hopper below. KingWo sizes this collector against the dust extraction air volume of the machine it serves, a range running from 2,200 m³/h on a Q326 tumble belt unit to 38,000 m³/h on the largest roller conveyor machine. It is a dry collector. It captures particles, not gases.
How a Bag Filter Dust Collector Works
Gas enters the chamber, not the bags. Dust-laden air comes in through a side inlet and is spread across the bag bank by a baffle, so that no single row takes the full stream. Flow is outside-in: gas crosses the fabric, dust stays on the outer surface, and clean gas passes into the plenum on the clean side.
The cake does the filtering, not the cloth. Within minutes of start-up a dust layer builds on the fabric and takes over the separation. That single fact governs everything downstream: the cake is the efficiency, so cleaning has to be strong enough to hold pressure drop and gentle enough not to strip the fabric back to bare cloth.
Pressure drop drives cleaning, not the clock. As resistance rises to the set point, the controller fires compressed-air pulses down a blowpipe above each row of bags. The pulse flexes the fabric, cracks the cake and lets it drop. The sequence runs row by row while the rest of the unit keeps filtering, so the collector never stops to clean.
Dust leaves at the bottom. Released cake falls into the hopper, is funnelled by the slope and leaves through a rotary valve or a double flap valve. The valve also stops room air being drawn up into the hopper between discharges.
The fan sits downstream. Because the fan pulls rather than pushes, the housing runs under negative pressure. A worn gasket or a badly seated bag draws air in; it does not blow dust out into the workshop. Bag condition shows on the pressure gauge before it shows up as dust on the floor.
Round Bags, Flat Bags, Top-Load or Side-Insert
Bag shape and bag access are two separate decisions, and they combine freely. Shape sets how much cloth fits in a given housing; access sets which building the collector can be installed in.
Round bags | Flat (envelope) bags | |
Element | Cylindrical bag on a wire cage | Flat panel bag on an internal frame |
Cloth area per unit of housing volume | Lower | Higher, because panels stack closer than circles |
Cleaning behaviour | Even expansion around the circumference | Stronger flex at the panel centre, weaker near the seams |
Wear pattern | Abrasion ring at the inlet row | Seam and stitch-line erosion |
Typical fit | Larger air volumes, taller housings | Shallow housings, mid-range air volumes, tight headroom |
Top-load | Side-insert | |
Bag removed through | Top access, vertically | Side door, horizontally |
Headroom needed | Bag length plus withdrawal clearance | None above the unit |
Clearance needed | Above the housing | Beside the housing, at door width |
Suits | High-bay buildings, outdoor installation | Low-bay buildings, units under crane rails or existing ductwork |
Modular delivery | Sectional housing, assembled on site | Sectional housing, assembled on site |
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Product Description
Pulse-Jet Cleaning and Bag Replacement
Pulse settings follow pressure drop. Cleaning triggers on differential pressure, with a timer as the fallback where the dust load is steady. Pulse pressure and duration are set at commissioning against the dust actually being collected, not against a nominal value.
Compressed air has to be dry. Moisture in the pulse air blinds the fabric and shortens bag life faster than abrasion does. A refrigerated dryer and a filter at the collector inlet are part of the air supply, not an accessory.
Media is chosen per application. Polyester needle felt is the standard medium for abrasive dust at ambient temperature, with an antistatic variant where the dust carries low ignition energy. Two variables override that choice: gas temperature and chemistry. Above the service ceiling of the media, the bag does not merely wear faster, it fails — so where the exhaust is hot or aggressive, the medium changes and the specification is confirmed in writing before the order.
Replacement is individual. A damaged bag comes out on its own: cage out, bag off, new bag over the cage, back onto the tube sheet. Neighbouring bags are not disturbed and the rest of the unit keeps running. On a top-load unit the work happens above the tube sheet, clear of the hopper; on a side-insert unit it happens outside the housing, through the side door, with no one entering the dust zone.
Bags are a wear item. Abrasive dust erodes cloth at the inlet row in particular. Bags are consumed in service and are stocked against that consumption — two years of consumption is the level worth holding at site.
Where Bag Filters Fit, and Where They Do Not
Where they fit:
Shot blasting and sandblasting: the matched extraction unit that ships with a KingWo machine, or a replacement where the original system no longer keeps up with the extraction volume.
Foundry: sand handling, shakeout, and blasting or grinding stations.
Iron and steel: transfer points, bunker vents, ladle and casting dust.
Cement, lime and building materials: crusher, mill and belt transfer dust.
Chemical and pharmaceutical: powder weighing, mixing and pneumatic conveying.
Bulk handling: silo vents, elevator heads and truck loading spouts, where local capture avoids a long duct run.
Where they do not fit:
Gases. A bag captures particles. Sulphur dioxide, hydrogen chloride, VOC and mercury pass through the fabric and need a scrubber, an adsorber or an RTO instead.
Wet, sticky or hygroscopic dust. Damp and tar-bearing dust bridges between bags and in the hopper, and the pulse cannot clear it.
Combustible dust, without review. Where the dust can explode, venting, isolation, grounding and media selection are settled before quotation, not after.
Heavy pre-load. Where the inlet load is high, a cyclone separator upstream takes the coarse fraction and the bag filter polishes the rest; run on its own under that load, the bag filter cleans too often and the bags wear out early.
Boiler flue gas and other high-acid, high-moisture streams. These need a different media family, a different casing specification and usually a pre-treatment step. They are outside what this page covers.
One caution that belongs on the page rather than in a footnote. Quartz sand is crystalline silica, and a dust collector controls exposure at the source; it does not make the dust harmless. Local occupational exposure limits, respiratory protection and housekeeping still apply, and in several markets silica sand is restricted outright.
Delivery, Installation and Service
Standard configurations ship 35–60 days after receipt of order; non-standard builds and export crate packing are scheduled separately.
A complete-set quotation covers the blast system, the dust collection system and the wear parts listed for that model; the collector can also be quoted on its own, in which case it is deducted from the machine price. Freight, insurance, duties and third-party inspection are excluded.
Installation and commissioning are not included. They are quoted at USD 135 per man-day, with overseas travel borne by the buyer; self-installation is supported with remote guidance.
The buyer's scope is unloading, lifting, foundations, and connecting power and compressed air to the collector interfaces.
Warranty is 12 months from the final acceptance certificate, excluding normal wear parts.
Any quality issue reported by the buyer gets a written response within 24 hours; engineers are dispatched within 7 working days of a written request.
Voltage is built to the destination standard; motor selection is confirmed in writing at order, and power ratings can differ between voltage variants.
Technical Specifications
Q: Round bags or flat bags — which one do I need?
A: By housing height and air volume. Round bags suit larger air volumes and taller housings, and expand evenly around the circumference during cleaning. Flat (envelope) bags pack more cloth into the same housing volume and suit shallow housings at mid-range air volumes. The filtration principle, the cleaning method and the media are identical; only the geometry changes. On flat bags the seam line is the wear point; on round bags it is the ring at the inlet row.
Q: Top-load or side-insert — can it go in a low-bay building?
A: Choose side-insert for a low-bay building. The real difference is which dimension each type spends. A top-load unit withdraws bags vertically and needs headroom of bag length plus clearance, in exchange for a smaller footprint. A side-insert unit withdraws bags horizontally and needs no headroom at all, in exchange for door-width clearance beside the housing. Neither is smaller in absolute terms — footprint moves with bag spacing and module count. Send the available headroom and the side clearance and the choice is fixed.
Q: How do I size a collector for my shot blasting machine?
A: By the host machine's dust extraction air volume. The parameter table lists it per series and the full range runs from 2,200 to 38,000 m³/h; two machines of the same series can sit at opposite ends of that band, so the model matters more than the series. Send the model or the measured volume at each hood and the filter area and fan selection come back with the quotation.
Q: What outlet dust concentration can you guarantee, and against what standard?
A: Against the limit agreed in the contract, with the figure and the governing standard — the destination limit or GB 16297 — confirmed in writing at quotation. Filtration velocity is fixed at the same stage, from the dust load and the media: run it high and the filter area shrinks while bag wear rises; run it low and the unit grows while bag life extends. A single blanket figure here would be worse than no figure.
Q: Can it handle high-temperature or corrosive dust?
A: Yes, and the limit is the media. The standard medium is polyester needle felt for abrasive dust at ambient temperature, with an antistatic variant where the dust carries low ignition energy. Where the gas runs hotter than polyester allows, or is chemically aggressive, the medium changes and the specification is confirmed in writing before the order.
Q: Is cleaning pulse-jet or reverse-air? Can you supply mechanical vibration?
A: The standard configuration on this page is pulse-jet cleaning, triggered on pressure drop or on a timer, firing row by row with the unit online. Reverse-air and mechanical-vibration cleaning are not confirmed in our documentation, so this page neither quotes nor promises them; where that configuration is genuinely required, the model and its applicable conditions have to come from engineering first.
Q: How often are bags replaced, and does the unit have to stop?
A: On condition, not on a fixed interval. Abrasive dust erodes the inlet row first, so inspect that row on a schedule from start-up and build a replacement record from it; two years of consumption is the stock level worth holding. Replacement is individual — cage out, bag off, new bag on, back onto the tube sheet — without dismantling the housing, and the rest of the unit keeps running. Top-load units are serviced from above; side-insert units from the side door, without entering the dust zone.
Q: Can it be combined with a cyclone separator?
A: Yes. On a high inlet load the cyclone takes the coarse fraction first and the bag filter polishes the remainder, which lowers both cleaning frequency and bag wear. The fan has to be resized for the series, because the cyclone itself costs roughly 800–1,500 Pa. The cyclone is a separate product line with its own specification page.
Q: What about sticky dust, acid gas, boiler flue gas or explosive dust?
A: This is a dry bag filter; it captures particles. Acid gas, VOC and mercury pass through the fabric and need a scrubber, an adsorber or an RTO instead. Wet, sticky and hygroscopic dust bridges between bags and in the hopper, where the pulse cannot reach it. Boiler flue gas is a high-acid, high-moisture stream needing a different media family and casing specification. Combustible dust requires venting, isolation, grounding and media to be settled before quotation. None of these four is covered by the standard configuration on this page.
Q: What are the lead time and commercial terms?
A: Standard configurations ship 35–60 days after receipt of order; non-standard builds and export crate packing are scheduled separately. A complete-set quotation covers the blast system, the dust collection system and the wear parts listed for that model, and the collector can be quoted on its own and deducted from the machine price; freight, insurance, duties and third-party inspection are excluded. Installation and commissioning are quoted at USD 135 per man-day with overseas travel borne by the buyer, and self-installation is supported with remote guidance without affecting the warranty. Warranty is 12 months from the final acceptance certificate, excluding normal wear parts; quality issues get a written response within 24 hours and engineers are dispatched within 7 working days.
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