![A RoboVent Senturion system inside a shop.](https://cdn.thefabricator.com/a/6-design-considerations-for-localized-fume-control-1694202826.jpg?size=1000x)
Retailers have just a few issues to contemplate when designing a localized fume extraction system for welding. This consists of figuring out which welding applied sciences and supplies it makes use of, fume publicity dangers, filtration necessities, the mobility of welding operations, power financial savings, and spark management.
Weld outlets have plenty of choices in terms of designing a localized fume extraction system for guide or robotic welding. Tailoring the system to the wants of welders and the manufacturing atmosphere will assist reduce prices and power consumption whereas offering most safety for individuals. Listed here are six issues for system design.
1. What Welding Applied sciences and Supplies Are Used?
The kind of welding and the supplies getting used can have a big effect on the entire quantity of fume produced in addition to its general toxicity. Basically, welding processes utilizing consumables, akin to fuel metallic arc welding, shielded metallic arc welding, or flux-cored arc welding, will generate extra fume than laser welding or resistance welding. Some supplies are additionally extra poisonous than others; for instance, welding chrome steel generates harmful hexavalent chromium, whereas galvanized metal produces fumed zinc oxide.
Employers are answerable for guaranteeing that the weld fume assortment system retains employee publicity below the permissible publicity limits (PELs) set by the Occupational Security and Well being Administration (OSHA). The federal government company has set a PEL for complete weld fume focus at 5 mg/m3 when welding gentle metal, iron or aluminum, primarily based on an eight-hour time-weighted common. Nonetheless, PELs for particular parts present in weld fume, akin to hexavalent chromium and lead oxides, are a lot decrease. Which means merely assembly the 5-mg/m3 commonplace for complete weld fume just isn’t sufficient.
Facility testing is an effective place to begin to assist outlets turn out to be conversant in the weather present in its weld fume and what its present exposures are.
2. The place Are Individuals Uncovered to Weld Fumes?
A localized fume assortment system begins with the hood or assortment machine. The hood should be designed to maintain weld fumes out of the respiratory zone of employees. For optimum power effectivity and minimal weld fume publicity, accumulate weld fumes as near the supply as attainable.
Robotic welding cells will be contained below a full hood. The hood must be designed to reduce the airflow required to gather weld fumes. Nobody ought to work contained in the hood. Robotic tip extraction is another for purposes that can’t be simply hooded or for cobots working alongside individuals.
For guide welding, select an choice that retains fumes out of the respiratory zone. Fume weapons generally is a nice alternative for GMAW. With correct approach, they’ll take away 90% to 95% of generated fumes and reduce the airflow required for assortment. If utilizing a backdraft plenum or fume arm, be sure it’s positioned to tug fumes up and away from the welder’s face.
3. Ought to Air Be Exhausted or Filtered?
For light-duty outlets with occasional welding exercise, air flow system with localized fume seize could also be adequate. Nonetheless, high-production outlets nearly all the time require a mud assortment system. These methods seize and filter weld fumes earlier than returning air to the power or push it outside. An air filtration system retains amenities compliant with EPA guidelines and different rules for exhausting contaminants to the outside and saves power by holding heated or air-conditioned air inside the power.
A cartridge-style mud collector is really useful for many welding purposes. These collectors are extremely power environment friendly and supply extra airflow in a smaller bodily footprint than baghouse collectors. In addition they will be outfitted with higher-efficiency air cartridge filters to gather submicron particles created by thermal processes like welding. For weld fume assortment, a filter with a minimal effectivity reporting values (MERV) score of a minimum of 15 is really useful. Additionally it is vital to dimension the mud collector appropriately. It should present sufficient airflow to take care of required seize velocities and have sufficient filter media (air-to-cloth ratio) for the quantity of fumes collected.
4. Is Welding Stationary or Cell?
The proper kind of mud assortment system is determined by what number of welding stations there are, the configuration of the power, how a lot mobility is required by particular person welders, and the way a lot flexibility is desired for future progress or reconfiguration.
![A RoboVent Senturion system outside a shop.](https://cdn.thefabricator.com/a/6-design-considerations-for-localized-fume-control-1694202831.jpg?size=1000x)
A well-designed fume extraction system will assist convey a facility into compliance, scale back power use, and maximize worker consolation and security.
There are a number of choices to contemplate:
- A centralized ducted system. This can be a configuration wherein a number of robotic cells or guide weld cubicles/stations are ducted to a single, massive mud collector that’s generally positioned outdoors. This selection is greatest for bigger amenities with many particular person weld cells/stations and environments the place manufacturing line configuration is comparatively mounted.
- Particular person, smaller mud collectors. These models will be positioned on the manufacturing unit ground and ducted to at least one or two cells/stations. This can be a nice choice for smaller outlets that solely have just a few weld cells/stations to assist. This configuration might also be helpful for bigger outlets that need extra flexibility to reconfigure manufacturing traces, because the mud collectors will be moved with the cells.
- Moveable hi-vac mud collector methods. These models are most sometimes used for guide welding (fume weapons or a small moveable backdraft plenum or fume arm), although some are highly effective sufficient to assist a light-duty robotic welding setup. Moveable methods are nice for small outlets that simply have to assist one or two welding stations or for environments that require plenty of welder mobility. Combining a fume gun with a conveyable fume extractor offers welders the liberty to maneuver round massive weldments, work in semi-enclosed areas (akin to a tank or ship hull), and take their welding setup from station to station.
5. What Vitality-Saving Alternatives Exist?
Designing an energy-efficient system begins with choosing the suitable mud collector. A appropriately sized cartridge mud collector is often essentially the most energy-efficient choice.
For added power financial savings, search for these options:
- Variable frequency drive (VFD) motors ramp the motor up and all the way down to compensate for filter loading, so the system solely works as onerous because it must. A VFD motor can lower power use by 20% to 40%.
- A filter pulsing system reduces power use and upkeep by pulsing extra mud off the filters to reduce filter loading. This extends the lifetime of the filters and reduces the power required to push air by way of them. Search for a pulsing system that pulses mud throughout your complete size of the filter.
6. Is Spark Management Required?
Most welding processes produce plenty of sparks. These sparks can create a fireplace or combustion danger contained in the mud assortment system. Spark management is often mandatory on the inlet of the mud collector or ductwork to stop sparks from reaching the filter chamber.
Some mud collectors are outfitted with a mesh or screen-type spark entice. These are easy units that block sparks from coming into the inlet. They should be cleaned periodically to take away soot and particulate.
A centrifugal spark arrester can present extra safety for environments the place a lot of sparks are produced close to the mud assortment system inlet. These methods use centrifugal drive to drive sparks in opposition to the chamber partitions and strip the thermal envelope.
Placing It All Collectively
Designing a localized weld fume assortment system that’s each efficient and environment friendly will be complicated. It’s often helpful to work with a professional engineering associate who can conduct facility testing earlier than and after set up and enable you make one of the best selections on your operation. The proper system will hold your facility in compliance, scale back power use, and maximize the consolation and security of workers.
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