The importance of filter maintenance in factories

SMC Corporation has dubbed October ‘Filter Awareness Month’, in a bid to generate awareness and education around the importance of air filter maintenance in the factory.

One of the last things people notice around a plant are the air filters; however, Robert Taylor, Product Specialist for SMC Corporation Australia New Zealand (ANZ), argues that their role in a system cannot be overlooked.

“When it comes to the cost of maintaining filtration, one needs to consider the cost of downtime that occurs each time air quality issues result in component failure. In a food environment, for instance, exhausts from the air system are in close proximity to food products and products can be spoilt through contamination when an air filter fails,” Taylor said.

According to Taylor, there are two key benefits to properly maintained air filters:

1. Efficient equipment: With proper maintenance, machinery and processes will run efficiently and economically.
2. Reduced contamination: Filter maintenance helps keep contaminants out of cylinders, valves and other pneumatic components.

A common misconception and reason for resistance to maintenance by some manufacturers comes down to ‘downtime’, which in most cases can be easily avoided.

“An air system that runs 24/7 should have a bypass system around the filters, allowing maintenance downtime to take place without disrupting the air supply,” Taylor said.

Taylor recommends replacing filters every two years or when a 0.1 MPa pressure drop is recorded. This, however, depends on the environment. For example, a dirty or dusty environment will see the filter becoming contaminated more quickly.

SMC filters contain a red and green indicator at the top of the filter that indicates when the pressure drop through the filter is higher than the optimum level. Pressure sensing options can also be added to SMC’s modular range for remote monitoring of pressure differentials across filters.

Other signs that filters need replacing include the machine slowing down or not performing as it should be, which will become evident with an increase in pneumatic component failures. Another giveaway could be a discolouration in the silencers installed in the valves. In the case of very fine oil mist, operators may start to smell or feel the oil in the exhaust air.

While SMC offers a wide range of filters, Taylor believes the AFF main line filter series should be the base of each system.

“This is a 3-micron or 1-micron filter which offers a basic level of filtration to ensure that the bulk of the contamination is removed before going into the factory air system,” Taylor said.

A water separator should also be added to the air preparation system if there is any suspicion that it is trapping condensation.

“The next line of defence for removing water is drip legs and aftercoolers,” Taylor said.

Taylor also urged manufacturers to carefully consider the filtration system design.

“It helps to optimise the cost and performance of a system. In the compressor room, you should design your filtration to cover off the minimum level required by the factory. This way you do not over-invest in filtering air to a level that may not be required by some of your equipment. The filtration should then be ‘adjusted’ at the entry to a machine that may require a higher quality of air. This, in turn, minimises the cost of the filtration and maximises the performance of your system,” he said.

Top image caption: Robert Taylor, Product Specialist for SMC Corporation Australia New Zealand.