Dust Is Not a Sweeping Problem: Fix Capture Points Before You Buy

Look at the top of a cable tray in a plant whose floor is mopped twice a day. There will be a visible layer, and that layer is the honest measure of a dust programme: not how often someone cleans, but how much dust escaped capture. Buying a bigger vacuum does not change that number. Moving the hood does.

1. Why Sweeping Harder Does Not Work

A broom or an air lance lifts settled dust back into the air. Coarse particles fall nearby; fine particles travel and settle higher, on beams, fittings and cabinets. The next pass reaches the floor again. Repeat for a year and the workshop looks clean at eye level and fails an inspection at two metres.

Two enforcement cases published in China on 10 November 2026 follow that pattern: heavy dust accumulation at one plant, no cleaning system at another. Inspectors record what is visible; the dust came from generation points, not from an untidy floor.

2. The Three Capture Points

Dust leaves a process at three places, and each one needs a different countermeasure. Most failed programmes cover only the third.

Capture Point	Where It Happens	What Actually Works	What Does Not
Generation	Cutting, grinding, drilling, crushing, dosing, bagging	A hood at the tool — enclosed where possible, otherwise a close side-draft or receiving hood	Floor cleaning after the fact
Transfer	Drops between levels, machines, silos and bags	Partial enclosures, shorter fall heights, sealed bin emptying	Owning the point, but assigning it to no department
Settled dust	Beams, fittings, cabinets, floor	Filtered vacuum with a floor nozzle, then wet cleaning for oil-bound deposits	Brooms and air lances, which re-suspend the fine fraction

For generation and transfer, the question is not whether a hood exists, but whether it intercepts dust before the dust becomes room air. Transfer points are cheap to fix and easy to forget: they belong to no department, so nobody budgets for them.

For settled dust, remove it, do not agitate it. Dry first, wet second — vacuum picks up the loose fraction, and wet cleaning handles what is bound to the surface by oil or moisture.

3. The Hood Is the Cheapest Upgrade You Will Make

Capture performance decays fast with distance. For a free-standing hood, the airflow needed to control the same dispersion roughly quadruples when the distance doubles, using a point-source approximation.

Hood Distance	Relative Airflow Needed	Practical Reading
30 cm	1×	The working reference. A 351 m³/h unit can hold a tool-level hood here.
60 cm	≈4×	Either four times the airflow, or acceptance that dust escapes.
120 cm	≈16×	No mobile vacuum fixes this. Bring the hood back to the tool.

This is why two machines with near-identical datasheets behave differently on site: the difference is not the motor, it is the hood and the duct. The cheapest retrofit is rarely a bigger vacuum — it is a shorter distance, a skirt on the hood, and a semi-enclosed station.

Capture velocity is the starting point. For general dust, 0.5–1.0 m/s across the hood face is a common range, higher for fine dust or stations near doors. Verify it with an anemometer, then confirm the flow pattern with a smoke test — a number that reads correctly at the face can still miss the dust cloud entirely.

4. Airflow and Vacuum Are Different Numbers

Airflow in cubic metres per hour governs whether the hood holds the dust and whether the duct carries it. Vacuum in kPa or mbar governs how much resistance the unit overcomes: long hoses, elbows, loaded filters, narrow nozzles. They are not interchangeable, and a single number on a datasheet tells you almost nothing on its own.

Machine Type	What It Does Well	Where It Fails
High vacuum, low airflow	Pulling material through a narrow nozzle, lifting from a crevice	A long hose or a wide hood — the flow cannot cover the opening
High airflow, low vacuum	Holding a large hood face and conveying dust down a duct	A crevice tool or a heavily loaded filter — resistance chokes it

Power in watts is an input, not an output. Two 1500 W units can deliver very different airflow and vacuum once the fan, the filter area and the inlet diameter differ. Ask for the output figures, then check them against your hood and duct.

5. Keep the Dust Moving in the Duct

After installation the common complaint is "it lost suction". Half the time it is a loaded filter; the other half, dust sitting in the duct. Below transport velocity, coarse particles settle, the free section narrows, velocity drops further, and the duct blocks — the failure accelerates itself.

Material	Typical Transport Velocity	Note
Light, dry dust (packaging, textile fibre)	≈15 m/s	Lower end is acceptable, but never below the settling point
General mixed workshop dust	≈18 m/s	Safe default for mixed metal, plastic and mineral dust
Metal swarf, heavy grit	≥20 m/s	Highest requirement; short runs only

Do not enlarge a duct for margin. A larger diameter means lower velocity and more settling — the instinct to oversize is exactly backwards. Minimise elbows, keep runs short, and seal the joints, because leaks hide at couplings and bin lids and quietly steal the flow you paid for. Portable units follow the same logic at a smaller scale: machine close, hose short, nozzle matched to the inlet.

6. Filtration and Filter Cleaning

Air returns to the room after filtration, so poor filtration sends the finest fraction straight back into the breathing zone. Three specifications decide the outcome, and only one of them is usually printed in bold.

Specification	What It Decides	Selection Note
Rating	The particle size the media is rated at — 0.3 micrometre is a common reference	Rating and efficiency are separate claims. Ask for the efficiency figure separately.
Filter area	How slowly pressure rise develops as dust loads the media	Larger area means longer intervals between cleanings; near 250 m² supports continuous work.
Cleaning method	Whether the unit can keep running without an operator	Shaker for intermittent duty, pulse-jet for continuous heavy dust.

A bad choice here does not show up as a failed machine. It shows up as an operator stopping every few hours to shake a filter, which in practice means the machine gets used less than planned and the tray stays dusty.

7. Five Questions Before Selection

1. Where does the dust come from, how much, and is it sticky or damp? Sticky dust bridges in ducts and on filter media; dry dust transports easily.

2. How many capture points, and how far is each hood from the source? Distance decides airflow far more than volume does.

3. How long is the duct, how many bends, how many machine connections? Every metre and every elbow is paid for in airflow.

4. How many hours per day, and can the unit stop for filter cleaning? Continuous operation demands larger filter area and pulse cleaning.

5. Is the dust combustible, and is the area classified? Ask this one first — it changes which machines are allowed at all.

8. Nameplate Data, for Reference Only

Verified figures from the current SIBEN catalogue, listed so the numbers above can be compared on a real datasheet. These are capacity figures, not performance guarantees — a 351 m³/h unit and a 531 m³/h unit can produce the same result at the hood if the duct is sized differently.

Model	Power	Airflow	Vacuum	Filter	Runtime / Notes
XC1500L (battery)	DC 24 V, 1500 W (500 W × 3)	351 m³/h	37 kPa (≈370 mbar)	0.3-micron, 250 m² area	100 Ah lithium, 3–4 hrs, 100 L bin, 50 mm inlet
XC2100L (battery)	DC lithium platform	380 m³/h	40 kPa	0.3-micron class	Manual pulse cleaning
XC2400T (corded)	220 V, 2400 W	354 m³/h	210 mbar (≈21 kPa)	0.3-micron class	71 dB(A), fixed stations
XC3600T (corded)	220 V	531 m³/h	—	0.3-micron class	Long arms, multiple points

9. Log It, Then Retrofit

The cheapest specification document you will ever own is a log kept for one month. Five columns are enough; a sixth writes your retrofit list for you.

That last column tells you which hood is too far, which transfer point has no enclosure, and which duct is settling. Retrofit in that order: capture first, duct second, equipment last. A shorter hood and a skirt are almost always cheaper than the next size of vacuum, and they work.

10. The Combustible Dust Boundary

For ordinary, non-classified workshops the sequence is unglamorous and reliable: capture at the tool, keep the duct fast, filter before the air returns, and vacuum the settled dust instead of sweeping it. Cleaning is the last step, not the first.

Frequently Asked Questions