Breathing easy

Furniture manufacturer installs upgraded fume extraction system

Practical Welding Today May/June 2007
May 8, 2007

A manufacturer of hospital and nursing home furniture upgraded its air filtration systems in its London, Ont., Canada, manufacturing plant.

Air filtration system

Being in the health care business, Carroll Healthcare Inc. supports the long-term health needs of patients. It's now doing the same for its welders.

Carroll Healthcare, London, Ont., Canada, manufactures a variety of furniture for the long-term health care market, including more than 20,000 beds yearly. It manufactures three bed lines and three ­furniture lines that include end tables, hutches, wardrobes, and dressers used in hospitals and nursing homes throughout North America, South America, and Asia.

The company was founded in 1977 and employs 108 people at its Canadian manufacturing plant and its U.S. distribution warehouse in Missouri. It is a division of the Invacare Continuing Care Group, based in Elyria, Ohio.

About two years ago, Carroll Healthcare management became interested in upgrading the air filtration system in the manufacturing plant. The system being used at the time was outdated and was not cleaning the air to their desired standards. The air quality inside the plant was better than the standards required by the Ministry of Labor, but employees had noticed a haze near the ­ceiling, sparking management's efforts to look for a better air filtration system.

Steve Walker, director of operations at Carroll Healthcare, said that the company philosophy is to be proactive at "doing the right thing" and providing the best working environment possible for employees.

"When something's not working, we find out why and get something that will work," he said.

With three robotic welding cells in use at the London manufacturing plant, the company's primary objective was to find air filtration units effective at removing impurities generated by high-volume robotic welding. The management team began its upgrade by looking at the various air filtration manufacturers and systems available. Next came site visits to other welding manufacturing plants that utilized air filtration.

While investigating robotic welding ­suppliers, one of the team members observed a Great Lakes Air Systems RoboVent™ self-contained air filtration unit. The company decided to purchase three floor-mounted, self-contained air ­filtration units for its robotic welding cells. The company also purchased one air filtration unit for backdraft fume extraction from two manual welding bays and one downdraft table for dust extraction from a sanding station. The units were standardized to work with Carroll Healthcare's welding cells, and the other air filtration equipment required minimal customization to work with other welding applications performed in the plant.

The RoboVent's hood, mounted over the welding cell, has a specially engineered spark arrester that prevents fires as it draws air laden with smoke, welding dust, and airborne particulates from the welding cell. The air travels through a duct to a self-contained collection and filtering unit that sits on the floor next to the welding cell.

The collection unit comprises a housing with a blower, motor, silencer, filter ­cartridges, and a compressed-air pulsing ­system to clean the filters. It also uses a patented filtration process in which air flows in a downward path. As the collection unit receives air from the hood, it immediately shifts the airflow 90 degrees downward through the filter elements, where the air is cleaned. This causes separation and deposition of the larger, heavier smoke and welding dust particles, which reduces the load on the filter cartridges.

Welding filtration collection unit

The collection unit's housing has a blower, motor, silencer, filter cartridge, and a compressed-air pulsing system to clean the filters.

The downflow of air within the collection unit reduces air turbulence and helps eliminate re-entrainment, or reblowing dust within the collection unit that has already been cleaned off of the filters, back onto the filters. Re-entrainment is the primary cause of short filter life.

Once the units were installed, Carroll management and employees saw an immediate improvement in air quality, according to David Shillinglaw, maintenance manager at the company. Shillinglaw said they did air quality testing before and after the installation of the RoboVent units and saw a 50 percent reduction in the amount of particulate in the air.

"The units have all performed well beyond our expectation," Shillinglaw said, noting that the effect of the new air filtration equipment has been significant. "The amount of particulate and dust accumulation on the robotic arm and weld fixtures is now a fraction of what we experienced prior to the implementation," he said. This, in turn, has meant less maintenance time required for cleaning the robotic equipment and the weld fixtures.

In addition, air-sampling tests have shown air quality to continue to be well above government requirements. Most important, employee morale has improved dramatically.

"Our employees saw a concern for their health on the part of the senior management and the owners of the company," Walker said.

Walker said that they have also enjoyed some unexpected, additional benefits as a result of the new air filtration equipment.

"Recycling filtered air back into the plant eliminates the need for an Environmental Certificate of Approval from the Ministry of Environment to emit pollutants and saves the cost of providing and conditioning makeup air that air extraction systems would require," he said.

Although Great Lakes offers a maintenance program for all of its equipment, Carroll Healthcare opted to perform its own maintenance on the air filtration units. Shillinglaw said Great Lakes provided ­training for him and his staff when the equipment was installed. A second refresher training session was also provided.

Both Walker and Shillinglaw said the decision to invest in modern air filtration equipment is an easy one.

"Just look around your plant and talk to your employees. You'll see and hear all the evidence you need to make the decision," Walker said.

Invacare Continuing Care Group, 1644 Lotsie Blvd., St. Louis, MO 63132, 800-347-5440,

Great Lakes Air Systems, 6612 Taylor Road, Columbus, OH 43004, 800-470-3430.

Welding filtration hood

Hoods mounted over the welding cell have a spark arrester that helps to prevent fires as well as remove smoke, dust, and particulate.

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