In this blog series, we go back to basics to underline the value of effective filtration in industrial processes – as both a contributor to workplace atmosphere management and to enhance productivity.
Here, we answer some of the questions most frequently put to the Donaldson BOFA team, focused on various topics. In this blog, we look at extraction performance and filter longevity.
Q How do I know that the extraction system is working correctly?
At the time of installation, a Donaldson BOFA portable extraction system will be tailored to meet the requirements of any given process, whether that’s for lasering, soldering, additive manufacturing, or another industrial application.
Depending on the system, Donaldson BOFA technology offers visual read-outs conveying instantaneous operating information covering temperature, blower status, airflow rates (actual vs target set point) and filter condition. This makes monitoring filter saturation levels simple and helps schedule filter exchanges in step with maintenance plans.
On systems featuring the Intelligent Operating System (iQ), historical performance data can be downloaded remotely and analyzed for filtration effectiveness. At the same time, sophisticated technologies inherent in Donaldson BOFA architecture mean that airflow will be automatically regulated to maintain filtration effectiveness over the filter lifecycle.
Instigating a schedule of routine actions will also go a long way to maintaining performance – these include:
- A daily visual inspection to flag up any equipment alerts or alarms that need to be investigated, linked for example to filter saturation levels.
- A weekly supervisor-led inspection to look at the physical condition of extraction devices/nozzles/enclosures/hoses and to check for damage, changes to configuration and correct operation.
- A monthly check for blockages, signs of dust or vapor/gas/odor carry over (remember to wear appropriate PPE).
- An annual service by an accredited competent engineer (like Donaldson BOFA’s) is recommended to check the effectiveness of the LEV system and assess airflow, pressure and control compared to the original commissioning report. This will include a filter condition and replacement record.
- Keeping a log of actions and findings to help inform future preventative maintenance and anticipate filter exchange schedules.
Q How often will I need to change the filters?
The blockage/saturation point at which filters need to be exchanged will largely be determined by the volume, size, and composition of the particles and fumes emitted during any given process.
Generally, there are two principal causes of shorter-than-expected filter life:
- Check whether the hose between the extraction system and the process is too restrictive (too long, too narrow, numerous bends or diameter changes). If this is the case, the system will have to work harder. So, for example, if it is losing 50% of its pressure capacity within the ducting system, this will only leave 50% of the capacity to draw air through the filters, hindering overall performance and decreasing time to filter blockage.
- Setting the airflow rate too high on the extraction system can also cause issues. If the motors are running at close to maximum speed to deliver the required performance, there is little room left to speed up as filters start to block. In this situation, reducing the flow rate may not capture the fume effectively, which defeats the object of the technology. The point here is that if you need to set the flow rate at very high rates to capture the fume effectively, that’s usually an indication that you need to move to an extractor with a higher capacity.
Filter life is also impacted by the process and the materials being worked. For example, when MDF is lasered it generates lots of small particles, which can cause the more expensive HEPA filter to block quicker than the pre-filter. So, to extend the HEPA filter life, the operator should invest in a higher efficiency pre-filter – Donaldson BOFA engineers can advise on the most appropriate set-up for any given process.
Operators should also consider whether they can reduce the volume of particles or gases they are generating to optimize filter life. In soldering, for example, turning down the temperature of the solder iron will reduce the amount of particles given off. In laser coding, if it’s possible to reduce the depth of the code while maintaining the desired mark quality, this will emit fewer emissions and increase filter life.
Finally, it’s worth reflecting on the role of system control in filter life. Donaldson BOFA’s Intelligent Operating System (iQ) independently monitors each filter within an extraction system, making it easier for manufacturers to identify any filters blocking faster than anticipated. In this instance, a system log can be downloaded and shared with Donaldson BOFA engineers, who can assess any root cause of premature filter blockage.
In the case of a particle filter, the iQ system measures the differential pressure across them and gives an on-screen display of any blockage. However, it’s more difficult with gas filters which saturate rather than block – here a VOC sensor can help detect the volume of chemicals, with any obvious smell providing a clear indication that a filter exchange is overdue.
