The purpose of a filter in a welding fume extraction system is to capture and remove airborne particulates from the workplace environment. Mechanical filters incorporate a filtering medium made from microscopic fibers (fiberglass, cellulose, or polyester fibers, etc.) woven in sheets and typically pleated in a “V” pattern. The pleating of the material increases the surface area of the filter providing an increased capture surface. This white paper discusses several important factors about filter replacement for a welding fume extraction system.
What are the types of mechanical filters and what do I need to know about each?
When should you replace the filter?
- Another factor that will help you anticipate the need to replace your filter includes how many hours and shifts you system is operating. The more hours and shifts worked, the sooner the filter needs replaced.
- Changes in climate or the environment may warrant a filter check and replacement. When companies do extensive maintenance in the summer months, it’s a good time to schedule a replacement of filters. In the fall and winter months, when windows and doors are closed due to cooler weather, it is a good reminder to make regular checks to ensure that the exhaust systems are functioning properly.
What filter should you use?
What are other indicators that can affect your fume extraction filter replacement strategy?
As particles are trapped in the filter, the medium becomes more densely clogged, or opaque, and the ventilation system motor and fan are forced to work harder to maintain optimal air flow. Eventually, the resistance of the filter reduces the air flow to an unacceptable level and the filter has to be replaced. Monitoring the static pressure across the filter is a good indicator of the tradeoff between desired flow rate and filter efficiency. Most filter replacement indicators use this method. If there is not a clear indicator on the system you are using for filter replacement – such as a light and/ or audible tone, as mentioned previously – you can estimate a regular maintenance/replacement strategy based on your welding process and arc time.
Filters have a specific surface life. Filter life is determined by (1) how long it takes the fine particles to penetrate into the filter weave and form a cake, and (2) the type of material (i.e., oily versus dry) penetrating the filter medium. Some filters are designed to be removed and properly disposed of when saturated, while others are designed to be reused if the system is equipped with a self-cleaning mechanism. In these systems, the filters are cleaned with blasts of compressed air directed through the filter. Typically these filters have a significant extended filter life because the cake on the outside of the filter is removed.
Of course, fume extraction filters – like any replacement parts – add certain costs to your operation. For as much as you might be tempted to cut costs, filter replacement isn’t a good place to do it. Not all replacement filters are alike – even if they are specifically designed to fit your system. Opting for a generic replacement filter over an OEM filter may impact the performance of your fume collection system, especially over the long term. OEM or genuine filters are made by the manufacturer of the equipment and will fit, seal and operate properly. Third party filter replacements are similar to the original filter, but may not be made according to the same specifications and design criteria as the OEM. In addition, if the OEM makes design adjustments to the equipment, the third party filter supplier could be making filters according to old standards. Generic replacement filters may be the less expensive option at the time of purchase, but they are likely to result in a waste of time, productivity and money over the long term.
Why should you create a filter replacement and preventive maintenance strategy?
Preventive maintenance is planned maintenance activity designed to ensure consistent and effective operation, improve equipment life and avoid system malfunction. The purpose of any fume control system is to help control worker exposure to welding fume. If not maintained properly, the system may not adequately control that exposure.
Preventive maintenance ensures that the equipment is consistently efficient and effective, and that long-term use does not subject the equipment to stresses or potential failures caused by improper care or handling. For instance, if the filter is clogged, the fan motor must operate at a higher level to try to operate effectively. This can result in reduced fume capture efficiency, motor failures or other associated issues.
A successful preventive maintenance strategy includes changing the filter on a regular basis. In addition, equipment operation and cleaning should be scheduled and coordinated to ensure that ducting is clean, fume extraction arms are tuned properly and more. Certain tasks must be scheduled at varying service intervals in order to keep the fume extraction equipment from experiencing any unexpected breakdowns. Preventive maintenance for industrial equipment is an effective way to maintain and extend weld fume control equipment operation and life.
When establishing a filter replacement and preventive maintenance strategy, keep the following suggestions in mind:
- Use Lincoln Electric genuine filters rather than a generic replacement filter. Lincoln Electric cannot warrant or ensure proper operation of the unit if a generic filter replacement is used. This can affect the operation of the system.
- Know the regulations, requirements and restrictions that apply to the filter’s disposal. It may be necessary to have the material tested in order to understand if the waste material is regulated. Environmental regulations regarding waste disposal can vary, depending on federal and local requirements.
- Make sure to have a consistent schedule for procuring and installing spare parts and conducting regular service.
- Allow for regular system checks of the cleaning program within the programmable logic controller (PLC) and the differential pressure monitoring system.
- Ensure that employees are not overexposed to airborne dust and contaminants during filter maintenance activities. Take any proactive measures necessary to protect against overexposures such as using protective equipment, disposable coveralls and/or respiratory protection.
What factors affect filter disposal?
Fume control is an integral part of any welding operation, and proper filtering is critical to an effective fume control system. Safe execution of filter replacement and proper fume exhaust system maintenance can help ensure employees are not overexposed to airborne particulates. This will result in a cleaner, safer, more efficient and more productive manufacturing operation.