What are the specific steps for daily cleaning of stainless steel ventilation pipes?

Specific steps for daily cleaning of stainless steel ventilation pipes

The cleaning of stainless steel ventilation pipes should be dry cleaning or wet cleaning according to the types of pollutants in the pipes (loose dust, bonded dust/oil stain), and safety protection and preparation should be done well before operation. The specific steps are as follows, which can be directly used for on-site operation guidance:

First, the preparation work before cleaning (general steps)

Safety and tool preparation

Turn off the main power supply of the ventilation system, and hang the warning sign "Cleaning, No Closing" to prevent misoperation.

Workers should wear dust masks, protective gloves and goggles (wet cleaning requires extra waterproof clothing).

Preparation tools: industrial vacuum cleaner (equipped with extended hose+brush head), special nylon brush for stainless steel, neutral cleaner, warm water, high-pressure spray bottle, water basin, waterproof cloth, dry rag, industrial hair dryer and wrench (used to remove flange/access opening).

Field protection

Waterproof cloth shall be laid on the ground below the air duct, and a water basin (for wet cleaning only) shall be placed below the manhole to prevent dust and sewage from polluting the environment.

Remove the manhole cover plates or flange connecting bolts at both ends of the air duct to expose the cleaning operation entrance; If the air duct has no access opening, easy-to-disassemble parts such as elbows and reducing diameters can be selected as temporary entrances.

Preliminary inspection

Check the pollution degree of the inner wall of the pipeline, whether there are rust spots or weld cracks, and confirm that there are no large debris jams before cleaning.

Second, dry cleaning (suitable for loose dust in the pipeline, such as building materials warehouse and chemical fiber workshop air duct)

Sectional cleaning

The operator holds a stainless steel nylon brush and brushes the inner wall at a uniform speed from one end of the air duct to the other end, focusing on the air flow dead angles such as elbows, tees and reducing diameters to avoid dust from spreading.

Start the industrial vacuum cleaner at the same time, aim the brush head at the scrubbing area, and suck the fallen dust in real time to ensure that the dust is completely collected and does not remain in the pipeline.

Detail cleaning

Clean up the dust on the sealing surface of the flange and the sealing strip of the inspection port with a brush to ensure that the sealing parts are clean and free of sundries.

Wipe the residual floating dust on the inner wall of the pipeline with a dry rag until there is no obvious dust adhesion on the inner wall, showing the true color of stainless steel.

Closing reset

Check the dust collected by the vacuum cleaner and dispose of it according to the industrial waste standard after sealing.

Reinstall the manhole cover plate or flange, and tighten the bolts with even force to prevent air leakage caused by uneven stress on the gasket.

Remove the warning signs and restore the power supply to the ventilation system.

Three, wet cleaning (applicable to the pipeline with bonded dust, oil, such as painting workshop, kitchen exhaust duct)

Detergent configuration

Mix neutral detergent and warm water according to the ratio of 1:20~1:30 (strong acid and strong alkali detergent are strictly prohibited); When the oil pollution is serious, special degreasing agent for stainless steel can be selected and diluted according to the product instructions.

Soaking softening

Spray the diluted detergent evenly on the inner wall of the air duct with a high-pressure spray bottle, focusing on the areas where oil stains and dust are bonded, and soak for 5-10 minutes to soften stubborn dirt.

Scrubbing and blowdown

Brush the inner wall repeatedly with nylon brush (steel wire ball is forbidden to prevent scratching the passivation film) until the oil stain and bonding dust fall off; When brushing, make sewage flow into the lower basin along the inner wall of the pipeline to avoid splashing around.

For areas with stubborn oil pollution, the cleaning agent can be sprayed repeatedly and the soaking time can be extended, and then brushing can be carried out.

Clear water washing

Fill the watering can with clean water, and wash the inner wall of the pipeline repeatedly until the flowing water is clear, free of foam and oil stain, and ensure that there is no residue of cleaning agent (residue will corrode the stainless steel surface).

Thoroughly dry

Wipe the visible moisture on the inner wall of the pipeline with a dry rag; Then, turn on the industrial blower, blow air at the inspection port for 1-2 hours, or turn on the fan of the ventilation system to run for 1 hour, so as to ensure that the inside of the pipeline is completely dry and prevent corrosion caused by residual moisture.

Closing reset

Clean up the sewage and tarpaulin in the basin and treat the sewage according to the requirements of environmental protection.

Install the manhole/flange and check the sealing performance; Remove warning signs and restore power.

Four, special scene cleaning supplement (corrosive environment duct)

If the air duct is used to transport corrosive gases (such as chemical workshop and pickling workshop), passivation treatment steps shall be added after cleaning:

After the inner wall of the pipeline is completely dried, apply a layer of stainless steel passivation paste evenly.

Let it stand for 10~15 minutes, and wipe the excess passivation paste with a dry rag to form a uniform protective film and enhance the corrosion resistance of the pipeline.

Conduct comprehensive passivation maintenance once every six months.