An underperforming dust collector is often the result of very high dust loading, ineffective cleaning, or a combination of the two. Left unchecked, these problems can result in unplanned downtime and increased operating costs.
So, while this is not necessarily an exhaustive rollout of potential issues, listed below you will find a handy checklist of measures you and your staff can take to avoid costly shutdowns and frequent filter changes.
1. Compressed air pressure is critical for cleaning: Compressed air pressure is vital for the performance and longevity of your dust collector. When compressed air pressure is too low, filter cartridges are not properly cleaned and that usually results in rapid downgrade and saturation. If air pressure is high, filter cartridges are used up faster and need to be replaced more frequently, driving up costs and maintenance. The quality of your compressed air is also critical. Moreover, the compressor must be strong enough to supply air at constant pressure, even when production is running at maximum speed and all users are demanding peak compressed air quantities.
There are three main boxes to check:
- Compressed air pressure must be always within the limits of constructor recommendations
- Compressed air should be oil and water free and
- Quantity of compressed air available should be sufficient for all users that perform simultaneous tasks.
2. The hopper is not meant to be used for storage. Evacuation equipment (rotary airlocks, screw conveyors, etc.) should be sized to unload the hopper before any accumulation occurs. Check and empty the dust bin regularly to prevent dust from the hopper coming into contact with the filter element.
3. Know about pressure drop: Increasing pressure drop across the collector affects the ability of the dust collection system to capture dust. A simple but important safety requirement is to change filters when airflow reaches a differential pressure (above the specified maximum specifications) or 120 - 150daPa / 4.8 - 6.0 in. wg.
4. Filters look dirty? Good! The rule in dust collection is that you don’t touch filters even when they look dirty because this is a proof they are working well. Dust cake on filter elements facilitates filtration. The only way to tell if filter elements are saturated and should be replaced is to look at the pressure drop of either the differential pressure gauge on the collector or the controller. Specifications vary according to constructor; for example, maximum pressure drop for Ultra-Web® cartridges is 150daPa / 6.0 in. wg. At this pressure drop, the cartridges are saturated and the compressed air pulsing system can no longer run full filter cleanout.
5. All for one and one for all: All cartridges in a dust collector must be changed at the same time. Why is that important? In general, cartridges must be allowed the time to condition themselves and become efficient. New filter cartridges have less resistance than old ones under operating conditions. When mixing old and new filters, the air flow will automatically pass through the least resistant path and circulate around new cartridges. This will force the fan to pull dust particles so deep into the new media that they will eventually become impossible to pulse-clean. Soon, these cartridges will be saturated and will have to be replaced earlier than planned.
6. Pulsing matters: Diaphragm valves must be checked yearly. Particularly when new cartridges are installed, it is recommended to check valves and ensure that filters are cleaned properly from the very beginning. It serves the budget too: the price of replacing diaphragm valves is much lower than the price of replacing old filter cartridges with new due to inadequate pulsing.
Special tip from the field: When testing pulse valves, make sure to wear the appropriate ear protection as noise levels can go up.
