Little things can cause big problems in baghouse dust collectors. Inefficient collectors increase utility costs. Faulty collectors can lead to costly downtime or even jeopardize employee health.
Moisture impacts dust collectors in a disproportionate way. It only takes a little moisture and a short amount of time for moisture to wreak havoc in your collector. You may encounter:
- Dust buildup on housing walls
- Bridging of dust at the hopper discharge
- Dust accumulation on the vanes of the hopper's rotary airlock valve potentially causing the airlock to seize
- Dust accumulation on pressure sensors resulting in false readings
- Dust settling on duct surfaces causing excessive weight
- Corrosion of internal metals.
- Plugged filter media.
- Premature failure of filter bags.
Common Causes of Moisture in Baghouses
- Humidity changes
- Temperature differentials
- Hygroscopic dust (sugars, salts, fertilizers, wood products, metal oxides, polymers, etc.)
- Mists or sprays added to the process airstream
- Moisture entering the collector through the cleaning cycle on pulse jet collectors
- Moisture entering through leaks in the housing and seams, or around bad seals
Recognizing Moisture in a Baghouse
Too often, high pressure differential readings and low airflow rates are the first indication that something is wrong and by then, much damage is done.
Because moisture may appear in your baghouse intermittently, check for moisture when the possibility of moisture is high and the dust collector is not operating. Wear protective clothing. Inspect the inside walls of the dust chamber for signs of moisture or rust formation.
Conduct a simple moisture test by taking a dust sample from the chamber wall and placing it on a paper towel. Squeeze the paper towel with the dust sample inside. If any moisture or oils are transferred to the paper towel, you have a moisture problem.
Ways to Prevent Moisture Related ProblemsAvoid condensation
and you eliminate most moisture related problems. A properly engineered baghouse design is the easiest way to do this. For existing systems, consider the following to catch, reduce or prevent moisture problems.