Also check the blowpipe — the pipe that delivers compressed air to each pulse valve. The blowpipe orifices should be clean and properly sized. A buildup of rust or scale inside the blowpipe reduces the orifice diameter and cuts pulse pressure by 15-30%. I've seen blowpipes that looked fine from the outside but had 60% of their cross-sectional area blocked by internal corrosion.

4. Structural and Mechanical Inspection Points

The dust collector housing, tubesheet, and hopper are structural components that most maintenance teams ignore until there's a visible problem. By then, you're looking at a major repair, not a maintenance task.

4.1 Housing and Tubesheet Integrity

The housing of a silo dust collector is typically 4-6mm carbon steel plate. It's not a pressure vessel — operating pressures are usually below 250 mmWC (2.5 kPa) — but it's subject to internal corrosion from condensation and external corrosion from weather.

Inspect the housing annually using ultrasonic thickness testing. Focus on the lower third of the housing and the tubesheet area, where moisture accumulates. A housing that started at 6mm and has thinned to 3mm is at risk of collapse under negative pressure. I've seen a 12-meter-tall dust collector housing buckle inward during a windstorm because corrosion had reduced the wall thickness by 50%.

The tubesheet — the plate that separates the clean and dirty air plenums — is critical. It's typically 6-8mm plate with holes punched or drilled for each filter bag. Check for corrosion around the bag holes, where the sharp edges of punched holes create stress concentrations and corrosion initiation points. If you find holes that have elongated or corroded to more than 110% of their original diameter, the tubesheet needs patching or replacement.

Seal integrity matters too. The gasket between each filter bag and the tubesheet is what prevents dirty air from bypassing the filter. A single failed gasket can increase emissions by 20-50%. Check gaskets during every bag replacement, and replace any that show compression set or cracking.

4.2 Hopper and Discharge Equipment

Бункер-накопитель в нижней части пылеулавливающего аппарата собирает пыль, очищенную от фильтрующих рукавов. Если в бункере образуется свод или происходит закупорка, пыль накапливается внутри аппарата и может повторно попадать на рукава, вызывая резкое повышение давления и возможный выход рукавов из строя.

Следите за чистотой бункера и обеспечьте исправную работу разгрузочного оборудования — роторного затвора или двухстворчатого клапана. Роторный затвор с изношенными наконечниками ротора будет пропускать воздух вверх в бункер, нарушая выгрузку пыли и вызывая её повторный унос. Зазор между ротором и корпусом должен составлять 0,1–0,3 мм. При превышении 0,5 мм замените ротор или