Next-generation regulators communicate information using colour-coding and graphics. The size differences between the gauges especially helps with oxyfuel processes, in which the more critical delivery pressure gauge is larger and the cylinder pressure gauge is smaller.

When managing your gases for cutting and welding or shielding, it’s important to know which type to use for the job: a regulator, a regulator flowmeter, or a flowgauge regulator. This article discusses which device is best for what kind of job.

A regulator essentially does one thing: It allows you to regulate the output pressure of the gas you’re using from the cylinder or pipeline. Regulators are adjustable pressure reducers designed to operate automatically after an initial setting. They are produced with different capacities for pressure and volumetric flow, depending on the application and source of supply. Common modern regulators are either single or two stage and have pressure gauges (two or one) that measure the pressure from the source of supply and delivery pressure, or flow rate. The reduction in pressure sets the gas at a usable pressure level for cutting, heating, and welding/brazing or flow rate for gas shielding in welding applications.

A regulator is the ideal tool if you are using a gas for cutting and heating because pressure and volumetric flow exiting the orifice at the cutting or heating tip is what is most important in this scenario.

There are several factors to consider when selecting a regulator. Some of these are the application or service function, total cost of ownership (TCO), source of supply (cylinder, pipeline), safety, and durability. Regulators can seem like straightforward devices, but engineering developments have made recent iterations much more rugged than their predecessors. Some are designed to protect valves and gauges from potential damage should a cylinder be knocked over or in some other way interfered with. Pressure gauges also have been designed to be easier to use for less experienced welders by colour-coding pressure levels to explain rule-of-thumb levels for cutting, heating, and welding. It is also possible to find colour-coded adjusting knobs to ensure the correct regulator is selected for the specific gas or variant it is intended to be used with. This offers employees a visual cue that’s easy to follow.

Regulator Flowmeter and Flowgauge Regulator Differences

Using a regulator flowmeter or flowgauge regulator is essential for welding because it’s necessary to know the cubic feet per hour or litres per minute a gas is flowing to provide adequate shielding of the weld metal deposit, bead shape, and penetration and to properly align with your welding parameters. Some welders are tempted to increase gas flow if they are in windy conditions, believing they are providing better shielding, but doing so can immediately put a job out of specification. Should an inspector on a shipbuilding or military job see a flowmeter that is out of the recommended flow specification, the job can automatically fail inspection.

Choosing between a flowmeter and a flowgauge depends on the type of work being done.

Four considerations to keep in mind when choosing between a flowmeter and a flowgauge are:

The two main flow control devices are regulator flowmeters and flowgauge regulators. While both are designed to regulate pressure and measure gas flow, they operate quite differently. A regulator flowmeter delivers the gas at a fixed pressure to a variable orifice (valve), and a flowgauge uses variable pressure to deliver the gas to a fixed (drilled) orifice. Either will give you the cubic feet per hour (CFH) or litres per minute (LPM) reading you seek.

Surge-limiting regulators, available with and without pressure gauges, mitigate the effects of a gas surge after the solenoid valve is opened. By reducing gas waste and controlling weld quality problems related to gas surge, they can provide a quick ROI.

While both produce the flow needed, each has unique characteristics. A regulator flowmeter always shows you clearly whether the gas is in a flowing condition because the ball in the meter will be suspended in its tube. Welders appreciate this simple visual cue on the job. They can tell if gas will be in a flowing condition prior to striking the arc and whether it is necessary to purge the system while welding.

A flowgauge regulator is a more rugged device that is useful out in the field. It’s possible to damage the flow (delivery) gauge and still be able to use the device. If you damage the flow tube on a regulator flowmeter, however, it is instantly unusable because the gas escapes into the atmosphere.

A flowgauge regulator can be as much as 50 per cent cheaper than a regulator flowmeter, and it’s more rugged, so for welders working in the field or that need to switch out tanks often on a shop floor, it’s going to handle being knocked around a lot better than a flowmeter.

When you’re welding – whether it be GTAW or GMAW – basically you pull the trigger or start the arc and it opens up the gas solenoid on the machine, allowing the gas to flow to provide shielding for the weld. When you stop welding, the solenoid shuts off. Because of the regulator flowmeter’s continuous flow, however, it is possible that the gas hose will expand in the process. This expansion might be slight – maybe 1/16 inch – but that slight amount over the length of a 50-ft. hose adds up, and all of that will come out the welding nozzle when you restrike another arc unless it is properly managed.

A surge device is designed to cut off the flow to the downstream solenoid much sooner than a regulator flowmeter or flowgauge regulator can provide alone. This stops pressure from building up and limits, or in most cases eliminates, that initial burst when you strike an arc.

This surge protection is particularly important when you are working on thin-gauge material, or any type of welding where it’s important to prohibit a large volume of gas from being released into the weld zone. When welding thin-gauge material without surge protection, you can end up blowing holes right through it. Even on the lowest GTAW setting, if you can’t control the surge, you are going to get a high volume of gas entering that welding area and superheating the material.

A lot of GMAW and FCAW-GS applications create opportunities for gas to get into and underneath the weld material or slag covering such that you don’t actually see the problem created by that surge of gas. This scenario was recently examined in terms of fast-freezing slag applications with a dual-shield type of wire. In this case, worm tracking resulted – gas became trapped underneath the slag covering because the high volume of gas didn’t have time to escape before the slag froze. When the slag was removed, what looked like a worm was on top of the weld. This type of work is common in structural steel and shipbuilding applications. So without surge protection, for a brief moment you might be getting a flow of 80 to 120 CFH rather than the desired 35 CFH.

Regulators, flowmeters, and flowgauges may seem like basic consumables, but be sure to consider what your job is, the material you’re using, and your environment to make the best investment for your team.

Curt Rocha is global product manager, ESAB Welding & Cutting Products, 2800 Airport Rd., Denton, Texas 76207, 940-381-1360, www.esab.com.

ESAB Welding & Cutting Products

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