Lions & Tigers & Flames, Oh My!

Turning on the Gas safely

I recently had a conversation with someone who was describing some upgrades to her church’s kitchen. The gas range was replaced with an electric one, she said. Since I’ve always heard that gas ranges provide a more even and responsive source of heat than electric coils, I asked her why they made the change. “People were afraid of gas,” she said. The sound and sight of open flame in the cooking surface frightened some of the church cooks – even though their cooking goes faster and more evenly using gas.

If people are nervous around the small amounts of gas used in a range cooktop, they should try flame hardening with fuel gas and oxygen flows hundreds of times at that level. Yes, the sight and the sound of gas-fired flames still makes some people nervous. But in our view, that’s not such a bad thing. The more alert people are on the plant floor, the more they’ll follow all safety precautions. As I’ve said before, in over 40 years of building flame hardening machines we’ve never had an operator injury. We build numerous safety features into each flame hardening machine to ensure this safety record will continue, and always look for ways to increase operator comfort and assurance.

For example, we now use electronic sensors to detect deviations in the pressure of either the fuel gas or the oxygen flow, as they occur. As a reminder – controlling the flow of fuel gas and oxygen to and from the machine is one of the most important safety and quality issues in flame hardening. Consistent and controlled flows produce consistent, controlled flames, which produce consistent hardness patterns and depth reliably each and every time. That’s both safe and necessary for quality results.

In the past, we used flow meters so that operators could monitor flows and stop the process if an oxygen spike occurred. Now, instead of simply registering the deviation on a meter that the operator must recognize, the electronic signal can now be used to send an alert to the control panel on the floor so anyone can see it. If the client desires, it can also trigger a shutoff. It’s an extra insurance policy that no issues with oxygen or fuel lines will cause safety or quality issues.

Like the cooks in my friend’s church, some plant managers simply don’t like having open flame on the floor. These folks can always install machines inside dedicated enclosures, or cages, or behind light curtains. We consider these options an added precaution. They aren’t necessary for the safe operation of the equipment – but if they make everyone feel better and most productive, we’re all for it.

Depending on the size and type of machine, our standard safety features include:

  • UV sensors that shut off the flow of fuel and oxygen when they can’t detect active flame;
  • Flow switches that shut off the machine if water stops cooling the flame heads, and prevents ignition if water isn’t flowing into the heads, preventing overheating;
  • Soft ignition and shutoff processes that gradually introduce and eliminate the oxygen flow, so that backfires do not occur;
  • Fuel/oxygen delivery systems that detect and help to prevent any uncontrolled spikes or irregularities in gas/oxygen mixture;
  • Reverse flow-check valves for both fuel and oxygen to stop any burnback (rapid burning reversing from the flame backwards into the torch);
  • Liquid flashback arrestors in the fuel supply system that extinguishes any flashback in the fuel line.

After ensuring the flow and torch safety, our next concern is the decibel level. You can’t really do much with the physics of pressurized gas and oxygen rushing through tiny flame ports and igniting with flame. The more torches, the louder the sound. Our 4-8 torch spinning machines have the highest decibel levels and operators MUST wear ear protection. On the other hand, 1-2 torch progressive or combination machines usually need no ear protection at all. So again, size and scope of the project determines the noise level, and for those very large installations we look for ways to mitigate the level on the plant floor (separate enclosures) and requiring ear protection for operators and those around the machine.

I hope this blog gives you an additional inside look at the safety issues of using flame hardening for your steel and cast iron parts. With an awareness of how to manage them, you’ll find flame hardening to be an affordable, effective way of conducting surface hardening in a broad range of applications – and particularly large, difficult geometric parts. You can use our equipment with confidence – and profit.

Call me if you have any questions or concerns installing or using flame hardening machines in your shop. 919-956-5208, or

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