High powered CO2 lasers are used increasingly in metal fabrication applications, for such jobs as cutting metal plate and sheet, but to function properly, these lasers require gases at various flow rates, pressures and purity levels.

Gases designed to be used in industrial laser applications can be classified into three categories: laser gases, assist-shield gases and purge gases, and each of these require specialized delivery systems.

Advanced Specialty Gas Equipment (www.asge-online.com) has produced a brochure to help companies that use laser cutting processes to select the equipment that is best suited for their particular laser gas delivery requirements in each of the three categories.

While the company primarily specializes in laboratory applications, one of its specialties is supplying industrial gases for laser cutting equipment, Fred Marencik, product manager for Advanced Specialty Gas Equipment, said.

For example, laser gases are used to generate the laser beam within the laser’s resonator.

“High-purity grades of carbon dioxide, nitrogen and helium are the most commonly used gases. They can be delivered to the user premixed or in component form. Maintaining a high level of purity while providing constant pressure and uninterrupted supply are the most critical requirements when selecting equipment for a lasing gas delivery system,” the company’s brochure said.

Delivering that high level of purity depends on the application, and on the expected amount of gas that will be used. Manual changeover systems are suitable for use in applications where gas consumption is low. Laser gas process racks that have automatic changeovers are recommended when gas consumption is moderate and, for high gas consumption applications, Advanced Specialty Gas Equipment recommends distribution systems that include automatic changeovers that are mounted in the cylinder storage area. These automatic changeover systems typically include remote line regulators and control panels at the point-of-use to provide the most efficient gas delivery.

Advanced Specialty Gas Equipment has developed a manual changeover system, its LMW Series, that the company said provides ultra high-purity laser gas delivery for installations that do not require automatic changeover. The LMW Series system is designed with a two-stage, brass bar stock regulator for two cylinder banks. The regulator can be switched manually from an in-service to a reserve bank. When the in-service bank is exhausted, it can be shut off and the reserve bank can be manually opened to replenish the supply.

Isolation and vent valves allow the exhausted bank to be replaced and purged without any interruption of gas supply to the laser.

The company’s PCS, CRS Series of equipment is an automatic changeover system that is designed to provide a continuous supply of laser gas from two or more high-purity cylinders.

These systems allow the user to deplete gas in a cylinder, and are designed to avoid gas outages and the waste of unused gas that can result from premature change outs. The PCS Series Primary Changeover provides single-stage pressure regulation and is designed for systems incorporating downstream line regulation. The LP Series Point-of-Use Panel is optional for downstream application.

The CRS Series changeovers provide two-stage constant delivery pressure control to the laser by incorporating an adjustable outlet line regulator in a compact design. The company said downstream line regulation is not necessary unless various distribution point pressures are required. Both the PCS and CRS Series are available in either brass or stainless steel, and are supplied installed on a stainless steel panel providing convenient, wall-mounted installation where space is at a premium.

Advanced Specialty Gas Equipment’s CRSL Series is an automatic changeover system with pressure switch gauges that regulates pressure and provides uninterrupted gas flow of laser gases. The CRSL utilizes the same mechanical design principals as the CRS Series, but incorporates two pressure switch gauges and an optional wall mountable annunciator to provide visual and audible alarms to alert the user of a changeover. The stand-alone annunciator can be located next to the changeover or mounted remotely to provide warning where personnel are present.

The Specialty Gas Equipment’s brochure on Laser Gas Equipment is available at the company’s Web site: www.asge-online.com/pdf/AdvancedSpecialtyGasEquipmentLaser.pdf.