When setting up a gas delivery system, it often becomes necessary to combine several components to work in unison. A given system, for example, could incorporate cylinder manifolds, an automatic switchover, an alarm system, a purge, filters, point-of-use control equipment, or other accessories. These individual pieces can be sourced separately to marry onsite, or they can be designed and assembled as a complete system from a single manufacturer or integrator. There are definite advantages in taking the systems approach:

Sizing. By utilizing a single design source, you ensure sizing all of the components correctly relative to each other and to the end-use requirements. It takes only one component in a series to limit the flow rate or capabilities of the system. If a component is oversized relative to the system requirements, it may not act as a restrictor, but you may be paying more than needed for capabilities that are not being utilized.

Materials compatibility. Particularly in applications for high-purity or corrosive, pyrophoric or toxic gases, it is important that the wetted materials (those in contact with the gas stream) be compatible with the particular gas service and the end-use requirements. Use of the proper materials of construction will limit contamination or leakage problems. Correct materials will also reduce galling (welding together of two components), fit-up or undue wear conditions. Again, a single source can ensure a correct design and compatibility.

Fewer connections. By designing a complete system it is possible to minimize the number of connections and adapters required to connect different components. Each additional connection is a potential new leak path. The use of adapters may also create flow or pressure restrictors and add unnecessary costs.

Cost and labor. It may very well be possible that the cost to put together a complete system will be lower than sourcing each item individually and separately. The labor involved in putting together the system should be less when performed by someone intimately familiar with the installation and operation of the component parts.

Preassembly and pretesting. A systems integrator will be able to preassemble and test the unit for the job for which it is intended. Sometimes components may work individually but are not compatible with downstream parts. Pre-testing as a system will minimize problems during setup at the jobsite.

Aesthetics. Assembling a system can enhance aesthetics by allowing for a more uniform look in the components and by presenting a more compact configuration if fewer adapters are required. Compactness is definitely an advantage where installation space is at a premium.

Gas flow efficiency. Designing the system also may allow for a more efficient gas flow. You may, for example, have a set up where all the gas inlets are at the six o’clock position and the outlets are at the twelve o’clock position. The elimination of piping bends and reducers will minimize pressure and flow restrictors in the line.

Case in point. CONCOA’s Bob Montgomery recently set up gas blending systems at vocational schools in Flint, Mich., and Paducah, Ky. In both instances the blenders supply the shielding gases to the MIG and TIG workstations. The blender can be dialed in to supply 100% argon, 100% CO2 or any mixture of the two, depending on the welding application.

Several components have been assembled to make up these gas supply systems. In one installation, the blenders are being fed directly from high-pressure argon and CO2 cylinders. In the other, switchovers are used to supply the mixed gases. Switchovers are used to ensure an uninterrupted supply of the gas from a reserve bank when the primary bank is depleted. It also allows for storage of the high- pressure cylinders outside the work area for safety reasons. The blenders are capable of supplying flows exceeding 1,000 scfh of shielding gases to the workstations. Each blender is piped to six workstations with plans in the future to expand to six additional workstations each.

At 1,000 cubic feet per hour, these blenders could eventually be expanded to more than 20 workstations per unit. Relief valves can be installed inline to protect downstream equipment against potential over-pressurization. At each workstation is a station drop that incorporates a quick shut-off valve, a preset regulator and compensated flowmeter.

All the equipment has been sized for the system’s requirements and to allow for future expansions. All the components work in conjunction as a system.

Dan Cruz is the director of Sales for CONCOA, manufacturers of gas flow control systems and equipment for industrial, medical, and specialty gas applications, as well as distribution systems for laser materials processing. Contact him at tel. 800-225-0473, or dan.cruz@concoa.com.