The Brain and Brawn Chemistry of the Gas Cabinet

Sep 11th, 2009 | gas delivery and welding equipment

Much of this blog has extolled the virtues of the modern-day gas cabinet. But the gas cabinet itself is little more than a locker on steroids: added security and safety features ensure that the gas within is well-guarded and well-monitored. The real brawn behind the operations of today’s gas cabinets are the gas panels that take commands from the automatic gas cabinet controller. In the past, gas panels – which regulate the flow of gasses from various cylinders and incorporate safety features like shut-offs, etc – had to be manually operated: regulators opened and closed, mixtures monitored, and complicated purge processes undertaken through a mind-numbing sequence of twists and turns. Today’s software, along with automatic controllers of today’s cabinets are the brains that control the on-board panel’s brawn. (Though it should be noted that cabinets can and often are output to other, external panels for further mixing, dispensation, refinement, etc)

But gas panels on their own are not as safe or intelligent as they are inside the automatic gas cabinet. Whereas standalone panels are often manipulated by their human controllers, an automatic gas panel provides the automation of the opening and closing of valves that – along with sensors that monitor pressure, leakage, temperature, etc – make production safer and improve efficiency by reducing waste. In addition, an automatic cabinet may incorporate a mass flow controller (MFC) that can provide precise supply where it is needed.

So as not to confuse the reader, below is included a rudimentary (read: not comprehensive) list of  gas panel component parts. From this, it should be easy to see how an automatic gas cabinet can automate so much of gas delivery. Components & features:

  • Regulator isolation valve. A valve that allows the high-pressure side and the delivery side of the panel to be isolated from one another.
  • High pressure side vent valve. Vents the panel directly upstream from the regulator to intake gas.
  • Low pressure side vent valve. The valve the vents for the delivery of gas, so long as the high pressure valve and any intermediate valves are also open.
  • Low pressure process valve. Shuts of the the delivery of gas to the process.
  • Pressure regulator. For compressed gasses, regulates volume.
  • Vacuum eductor. Often a venturi, used for purging.
  • Inert gas purge valve. Allows inert gas into the panel, usually from the high-pressure side.
  • Emergency shut-off valve. Will automatically turn off the cylinder source when tripped.