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what exactly is a Liquid flash back arrestors ? and why is it used ?

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Flash Back Arrestors

Oxy-acetylene torches and fuel pipelines are used for welding, cutting, heating, and brazing in metal fabrication workshops and a number of other other industrial facilities. The design of those torches has evolved over the years.

Today, you’ll see oxy-acetylene torches in safety-centered designs; still, they will cause serious accidents. Flashback is one among the common causes of accidents in these torches. Backflow, backfire, and sustained backfire are a couple of other causes. To avoid these, flashback arrestors are used. How do these devices work? Why are they important for any metalworking facility?

Definitions of various Fire Discrepancies you want to remember that is sustained by a Flash Back Arrestor.
  • Flashback, backfire, and sustained backfire are a couple of confusing terms. Knowing their differences would help immensely keep things in check .
  • Backflow: If the gas is operated at high pressure for a long time, it may flow back into the hose through the torch. However, this transversal occurs at low pressure. This may cause the blending of gases within the hose, which might cause severe fire or explosion.
  • Flashback: This occurs when the gases flowing upstream reverses their flow back to the equipment or hose. This flashback are often caused thanks to several issues like ambient operating conditions, improper use of a check valve, and so on. The gas that flows back to the hose may damage it and separate from the pipelines spread in other areas leading to fire and major explosion.
  • Backfire and Sustained Backfire: Backfire occurs when the hearth flame enters into the torch with a violent sound and fizzles out quickly. The backfire usually sustains for a couple of seconds. It is not considered a dangerous situation. However, in some conditions, the flame may still burn within the nozzle for an extended time producing a smoky flame and a whistling sound. If this happens, the users got to immediately close all the valves within the vicinity, else the flame may damage the torch and other torches, too. In most dangerous cases it’s going to cause a fireplace .

Going by definition, you’ll easily identify why flashback is dangerous, and why it must be prevented. The next section introduces you to flashback arrestor that can be used to contain the fire in oxy-acetylene torches and acetylene cylinders.

An Overview of Liquid Flashback Arrester Parts and Its Working

we are one of the leading manufacturers of liquid flashback arresters for oxygen and acetylene applications. They also provide a flashback arrester for acetylene cylinder. They comprise several components, which assure effective fire quenching. The following pointers will help you understand the working of these devices in industrial setups.

  • liquid flashback arrestor (FBA) features the following components:
    • Inlet pipe with check valve
    • Outlet pipe
    • Flow diverter
    • Relief valve
    • FBA liquid
  • The gas enters into the equipment through the inlet pipe at in-line pressure.
  • The pressure of the gas in the torch or cylinder may vary between 5 and 200 PSI depending on the type of gas used. In typical applications, the pressure of acetylene gas is maintained at 10–15 PSI.
  • The gas next passes through the check valve and the flashback fluid. The check valve and flashback fluid both create a double barrier between the high-pressure gas in the cylinder and downline users.
  • Next, the gas escapes from the FBA chamber and helps protect the application.
  • If a flashback occurs, the flame will enter into the device through the outlet pipe and enter the chamber filled with liquid at high velocity. The fluid quenches the flame and the check valve prevents the fluid from pushing upwards. Thus, the flashback is prevented from reaching the gas in the cylinder.

In addition to this, there is another interesting aspect of this system. The relief valve used in the system doesn’t open fast to relieve the pressure, which was created during the flashback. This valve prevents the systems from over-pressuring during the regular operating conditions. Also, it aids to vent the system during maintenance. These flashback arrestors have been in use for more than 60 years. 

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