According to a recent report from the Health and Safety Executive, in 2019-20 1.6 million workers suffered from work-related ill health. In the same period, 12,000 deaths were due to lung diseases linked to past exposures in workplaces riddled with dust and fumes.
VODEX was originally set up because one of our founders visited one such place and was taken ill shortly after. In the 10 years since, we’ve built a business based on keeping people safe from a range of health complaints, and now serve a large number of industries, with an equally broad selection of extraction solutions.
Our products are so effective and well-respected within the industry in part because, in most cases, they offer several levels of filtration and therefore, protection. In this blog, we’ll go into the types of filters and their uses across a range of solutions.
Different types of filters and their applications
For the sake of simplicity, there are essentially three different types of filters we work with:
- Particulate filters
- Carbon filters
So let’s find out more about each one, and how they play their part in protecting you whilst you work.
The first in our list of different types of filters are also the first line of defence against airborne toxins. Our disposable pre-filters are made of course materials and are designed to protect the more expensive and high-efficiency filters behind them by capturing the largest, heaviest particulates.
Pre-filters come in a wide range of types and material gradesl ostensibly taking the form of pads, bags, vee pleats or capture boxes.
In terms of grading, the old system was somewhat vague. Many different filters could be graded the same but still have different performance levels.
However, the new system hasn’t exatcly cleared things up entirely either! The filters themselves which adhere to it are much more efficient, but the grading can still be a little confusing.
It’s based on three particle sizes: 10 Microns, 2.5 microns and 1 micron. Pre-filters are generally rated at 10 microns. Then they are given a percentage of how much particulate they filter at that size.
One example would be a new ePM10 65%. Here, the filter stops 65% off all microns at least 10 microns and above, which would be the equivalent to the old F7 grade. However, because they’re pretty much comparable like for like, many filters still use the old grading system, allowing people to choose the terminology that makes the most sense for them.
Particulate Filters (Dust Filters)
Next in our list of different types of filters are particulate filters. Often called dust filters, our ‘main’ filters also capture particulates from substances like fibres, chips and powders that you’d find in construction, carpentry and stonemasonry industries.
Made from a dense weave of fibres, like pre-filters they’re rated according to how effective they are at capturing different size particulates and can come in many forms, from cartridges to bags, ‘socks’, box and cylinder filters. Unlike pre-filters, dust filters can be disposable or cleanable depending on the filter needed. If cleaned with a hoover, make sure it has a High Efficiency Particulate Air (HEPA) filter.
While EN 1822 regulations are now the official standard, as mentioned above filter gradings are commonly still referred to using the old, letter-based system. By far our most common is either the M Class or H Class. Both extract particles of sizes down to microscopic levels – the ones particularly likely to cause a lung disease.
M Class filters are mostly used to extract heavier dusts like aggregates, and many will filter 95% of particulates measured at 0.4 microns.
H Class filters also known as HEPA filter 99% (H10) to 99.995% (H13) of particulates sized 0.3 microns.
Our EN 1822-certified HEPA filters meanwhile extract 99.95% of particles sized 0.1 micron.
Carbon Filters (Gas Filters)
Third amongst our different types of machinery filters are what are commonly known as gas filters. Designed to filter gases and vapours, these are box filters filled with either baked or loose fill carbon granules.
They’re often used to filter out toxic smells like glue or isopropyl alcohol, and come in a wide range of formulas, where the carbon is treated in specific ways to increase its efficiency at filtering certain vapours and gases. In fact, carbon filters carry ratings according to those substances, with common ones including acid, formaldehyde, solvents, and alkaline.
Carbon filters are also often used alongside particulate filters to remove gas elements from fumes. For instance soldering or welding fumes are usually made up of between 80 and 95% vaporised solid contaminate condensed in air, while the other 20% to 5% are usually gases like nitrogen, carbon monoxide or argon. Here, the carbon filter will work to capture the gases, while the dust filter captures the rest.
Different types of applications for filters
As mentioned at the outset, many of our extraction solutions use different combinations of pre-filters, particulate filters and carbon filters depending on what it needs to protect against. This combination means your workplace is COSHH compliant, and your people’s health is protected.
Here are three examples of how different types of filters we provide are used in industries we serve:
AGP’s (Aerosol Generating Procedures) from high speed drills and scalers create potentially harmful airborne droplets and aerosol under 5 microns in diameter. Our new dental extraction systems are currently being clinically trialled and use a special five-pronged combination of special filters, including UVC sterilisation, antimicrobial hydrophobic mist filters, HEPAs and Carbons to ensure everyone is protected ‘at the source’ from all procedures that could carry potential bacteria and viruses like COVID-19.
Anything that makes something creates airborne contaminates. Our manufacturing extraction solutions often combine filters, typically a pre-HEPA carbon filter, along with wet filtration (see below) and a vent to atmosphere approach.
Hospitals are a prime example of where different types of filters are urgently needed – even more so since the advent of COVID-19. Systems here would often be filtered using a pre-filter HEPA carbon filter, or alternatively might vent to atmosphere depending on the hospital’s requirements and the particular area they’re used in.
Other types of filtration systems
While the different types of filters above appear in many of our solutions, there are some which require a more unique approach:
Cyclonic filters consist of a circular chamber which creates an air cyclone that filters particulate from the air stream by flinging the heavier dust to the outer edges. Cyclonic filtration is used mainly in oil mist extraction to remove either coolant or heavier metal swarf caked in oil. Cyclonic extraction systems can also be used as a heavier pre-filter or drop-out filter for processes like plasma cutting.
Wet extraction is used in industries that work with products that have high combustion risks, including woodworking, metal processing and recycling. For instance in the case of heavy sparking and swarf, or where volatile dusts like titanium, magnesium or aluminium are being produced.
It uses a fine water spray in a chamber of agitated water to fill the internal chamber with moisture (like the way a really dense morning fog settles on your clothes). The volatile materials are then drawn into the water and sink to the bottom. Most wet filtration systems include additional after filters such as mist eliminators and HEPA filters. The process is highly efficient, but mainly used as a measure for dust suppression and ignition control.
So that’s our whirlwind tour of our different types of filters and their applications.