A giant in gas distribution says some end users should ditch

Many laser-cutting facilities are exploring microbulk gas delivery as a way to improve their bottom lines. Often, these companies find that moving away from liquid nitrogen cylinders boosts their production capacity, slashes downtime, and frees up valuable floorspace.

Take, for instance, Cutting Edge Laser, Covington, Ga. The manufacturer of highly engineered metal and fabricated components was losing valuable floor space and incurring additional labor costs because of its gas-supply chain. The company used up to 40 liquid nitrogen cylinders, or dewars, per month to fuel its 2,000-W laser. Each dewar lasted 1 to 3 hr, depending upon the thickness of the steel being cut.

Doug Nielsen, co-owner, says that when the laser was running nonstop, the production team changed cylinders throughout the day. At any one time, about 10 full and empty cylinders took up valuable floorspace. Moreover, with each cylinder change-out, the laser-cutting line was down for about 30 min. The company installed a vaporizer, allowing a change-out while a tank was in use. But the production team still had problems maintaining sufficient pressure to keep the laser cutter running.

"Switching cylinders required a lot of operator intervention," remarks Nielsen. The production manager constantly adjusted pressure levels because the variability in the nitrogen sometimes reduced the cutting quality. This, in turn, necessitated reworking of the metal.

Cutting Edge's switch to an Airgas MicroBulk liquid nitrogen supply system significantly improved productivity. The system includes a Chart Perma-Cyl tank, which Airgas's custom-designed delivery vehicles refill as needed. Because Cutting Edge runs nonstop, the Airgas system reduces downtime as much as an hour.

Airgas installed a 1,500-liter VHP Perma-Cyl tank. A 200-liter VHP Perma-Cyl mounted on the delivery vehicle maintains pressure of 420 to 450 psi during refill. This significantly reduces production downtime resulting from the system being brought to operating pressure. The fairly constant pressure also minimizes bad cuts caused by unstable gas pressure from dewar change-out.

When gas is in short supply
Birmingham, Ala.-based Altec Industries Inc. makes aerial lifts and derrick diggers. It installed the MicroBulk System for its four-head seam welder. This new welding operation needed more gas than the old bulk-tank system could supply. To ensure enough gas was on-site, Altec took delivery of 1 to 12 cylinders of 90/10 argon CO2 every other day.

Then Altec installed a 1,500-liter Perma-Cyl argon tank for the seam welder and a second one for other welding stations. It also added a gas mixer and manifold for on-site mixing of the shielding gas, using a liquid cylinder for the CO2.

Safety issues a concern
For Cutting Edge and Altec, installing MicroBulk eliminates the problems caused by using cylinders. The same was true for Kemlee, Manufacturing, Galena, Kans. Specifically, the change let the manufacturer of stainless steel food service, laboratory, and residential equipment eliminate cylinder-handling safety issues and reduce cylinder rental charges, residual gas loss, and labor costs.

Cutting Edge installed a 1,500 liter VHP Perma-Cyl nitrogen tank near its laser cutter.	A connection between the delivery truck and MicroBulk tank ensures constant pressure during refills.
Airgas driver Kenneth Alexander refills the MicroBulk tank and adjusts the VHP Perma-Cyl. The truck maintains 420 to 450 psi during refills, minimizing downtime from bringing the system up to pressure.

About the author:
Ray Homan, market development manager at Airgas Inc., leads the nationwide market development program for MicroBulk. Previously, he was national sales manager for industrial gases and equipment, focusing on Airgas's bulk gas growth initiatives.