8.Smart Guide to Choosing Dust Collectors: Low-Pressure High-Volume vs. High-Pressure Low-Volume (2025 Edition)

1) What’s the Difference Between Low, Medium, and High-Pressure Dust Collectors?

 Quick Rule of Thumb:

• Large airflow & short distance → Low-Pressure (HVLP)

• Medium distance / multiple bends & hoses → Medium-Pressure

• Long hoses, hand tools, central vacuum → High-Pressure

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2) Long Hose on My Production Line — High-Pressure or Medium-Pressure?

Choose High-Pressure if any of these apply:

• Single hose >10–15 m, or ≥3 hoses used simultaneously

• Worst-case ΔP > 6–8 kPa

• Requires small-diameter nozzles (Ø32–50 mm) with stable velocity

• Central cleaning/recovery (multi-station, multi-floor)

Stay with Medium-Pressure if:

• Hoses ≤10 m, limited bends, 1–2 points active at once

• Enlarged duct diameter + fewer elbows keep ΔP < 6 kPa

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3) Pulse-Jet Cleaning by ΔP — What Thresholds Should I Set?

• Baseline (new filters): 600–900 Pa

• Normal Operating Range: 1000–1500 Pa

• Warning Threshold: ≥1700 Pa → system shortens pulse interval, alerts inspection

• Intervention Threshold: ≥2000 Pa → planned shutdown, inspect clogging, adjust A/C, or replace filters

• Low ΔP Alarm: indicates possible filter leak or bag failure

Pulse pressure commonly 0.4–0.6 MPa; always use ΔP-triggered cleaning + minimum interval to avoid over-cleaning and compressed air waste.

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4) Should HEPA Be Placed Before or After the Fan? How to Validate with DOP/PAO?

Best Practice: Main Filter → Fan → HEPA (HEPA as the last defense).
Especially critical for indoor return air, cleanrooms, and sensitive product processes.

HEPA Integrity Testing (DOP/PAO Scanning):

• Introduce PAO/DOP aerosol upstream

• Scan filter face, gaskets, housing joints, and doors

• Typical local leak acceptance: 0.01–0.03% (depending on standard)

• Establish ΔP baseline across HEPA, use as replacement trigger

• Frequency: upon installation, post-major overhaul, and annually (or per internal SOP)

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5) Combustible Dust in High-Vacuum Central Systems — How to Ensure Safety?

Explosion & Fire Protection Strategy:

• Conductive/Antistatic Components: conductive hoses, filters, cages; full system grounding and equipotential bonding (regular resistance testing)

• Explosion Isolation: mechanical flame-arrest valves, backdraft valves, or chemical isolation installed close to dust collector inlet (per NFPA/manufacturer guidelines)

• Explosion Venting/Suppression: outdoor → explosion vents directed to safe zones; indoor → flameless vents or chemical suppression

• Spark Detection & Extinguishing: mandatory when upstream grinding/cutting sparks are possible

• Documentation & Zoning: clearly define Zone 20/21/22, keep DHA records, and perform regular drills

⚠️ Note: High-vacuum systems generate high pressure and fast flame propagation — always validate isolation & venting locations with vendor manuals and local codes.

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6) Why Is Airflow Too Low But Vacuum Too High?

Likely cause: system resistance is too high, pushing the fan to a low-flow, high-pressure operating zone.

Possible reasons:

• Duct diameter too small / too many elbows / hoses too long

• High filter ΔP (blinding, poor cleaning, high dust load)

• Misaligned or throttled branch valves

• Air leaks at wrong points causing false readings

Troubleshooting sequence:
Valve positions → ΔP & cleaning cycle → duct blockage/leakage → fan belt/impeller contamination.