What are the cleaning and unblocking methods for the ventilation ducts of fume hoods?

Cleaning method

Preparation stage

Preparation of tools and protective equipment: Prepare appropriate cleaning tools, such as long-handled soft-bristled brushes, vacuum cleaners (preferably with slender tips), rags, and cleaning agents (mild and non-corrosive types should be selected to avoid damage to the pipes). At the same time, operators must wear protective equipment, including dust masks, goggles, rubber gloves, etc., to prevent dust and impurities generated during the cleaning process from entering the respiratory tract or causing harm to the skin.

Turn off the ventilation system: Before cleaning, be sure to turn off the ventilation system of the fume hood, including the fan and other equipment, to ensure operational safety and avoid accidents caused by the operation of the ventilation system during the cleaning process.

Preliminary dust removal

Use a vacuum cleaner to clean: Insert the slender suction head of the vacuum cleaner into the ventilation duct and move it slowly along the direction of the duct to remove as much dust, debris and other impurities on the inner wall of the duct as possible. Special attention should be paid to cleaning the elbows and branches of some pipes to ensure that the vacuum cleaner can reach these areas and suck up the dust.

Wipe the surface of the pipe: For corners that are difficult for the vacuum cleaner to reach or for residual dust, a damp cloth can be used for wiping. Wrap a cloth around a long-handled tool, insert it into the pipe and gently wipe the inner wall to remove stubborn dust and stains. When wiping, be sure to apply moderate force to avoid damaging the inner wall of the pipe.

Deep cleaning

Spray the cleaner: Dilute the cleaner in the proportion specified in the instructions and pour it into a spray bottle. Starting from the entrance of the ventilation duct, evenly spray the cleaner onto the inner walls of the duct, allowing the cleaner to fully moisten the inner walls of the duct to decompose and soften the oil stains, dirt, etc. inside the duct.

Scrubbing the pipes: After the cleaning agent has been in effect for some time (usually 15 to 30 minutes), use a long-handled soft-bristled brush to scrub the inner walls of the pipes. According to the direction of the pipe, scrub from top to bottom and from left to right in sequence to ensure that each part is thoroughly cleaned. For areas with heavy oil stains, the force and duration of scrubbing can be appropriately increased.

Re-vacuuming and wiping: After the scrubbing is completed, use the vacuum cleaner again to suck out the sewage and residual dirt in the pipes thoroughly. Then, wipe the inner wall of the pipe with a clean damp cloth to remove any remaining cleaning agents and stains. Finally, dry the inner wall of the pipe with a dry cloth to prevent water residue from causing rust or bacterial growth on the pipe.

Unclogging method

Check the location of the blockage

Observe the ventilation effect: When the ventilation effect of the fume hood significantly decreases, there may be a situation of pipe blockage. At this point, one can initially determine the approximate location of the blockage by observing the exhaust conditions of the fume hood, such as the exhaust speed and whether there is any lingering odor.

Segmented inspection: If the location of the blockage cannot be directly determined, the method of segmented inspection can be adopted. Divide the ventilation ducts into several sections and inspect each section one by one. Observation ports can be set at the connection points of each section or tools such as endoscopes can be used to check whether there are any blockages inside the pipeline.

Physical unblocking

Use unclogging tools: For some smaller blockages, professional pipe unclogging tools such as unclogging springs and pipe uncloggers can be used. Insert the unclogging tool into the clogged section of the pipe and push or break the blockage by rotating or advancing it. When using unclogging tools, pay attention to the force applied to avoid damaging the pipes.

High-pressure air gun unblocking: If the blockage is stubborn, a high-pressure air gun can be used for unblocking. Insert the nozzle of the high-pressure air gun into the pipe, turn on the air gun switch, and use the high-pressure airflow to disperse and discharge the blockage from the pipe. When using a high-pressure air gun, it is essential to ensure the safety of the operator and the people around them to prevent the high-pressure air flow from causing harm to the human body.

Chemical unblocking

Choose the appropriate chemical unclogging agent: For some blockages caused by oil stains, organic matter, etc., chemical unclogging agents can be used for unclogging. Select a chemical unclogging agent suitable for the material of the ventilation duct and dilute it in the proportion specified in the instructions.

Pour in the unclogging agent: Slowly pour the diluted chemical unclogging agent into the clogged section of the pipe to allow the unclogging agent to fully contact the blockage and exert its dissolving and decomposing effects. Wait for a period of time (usually 30 minutes to 1 hour) to allow the drain cleaner to fully take effect.

Flush the pipe: After the unclogging agent has completed its effect, use a large amount of clean water to flush the pipe, flushing out the dissolved blockage and the remaining unclogging agent from the pipe. You can use a water pump or bucket to collect water and pour it into the pipe for flushing to ensure there are no residues inside the pipe.

Professional assistance

Contact professional personnel: If none of the above methods can unclog the pipe or the blockage is rather complex, it is recommended to contact professional ventilation duct maintenance personnel. Professionals, with their rich experience and specialized tools, can solve pipe blockage problems more effectively.

Cooperate with maintenance work: When professionals are conducting maintenance, actively cooperate with their work and provide necessary assistance and information, such as the usage status of ventilation ducts and the time when blockages occurred, so that they can identify and solve problems more quickly.