Flame arrestor how does it work

A standard flame arrester has many small tubes that help to produce the required venting capacity while preventing the passage of flame. It works on the principle that the speed of the flame decreases with the reduction in the diameter of the pipe. When the pipe has a very small diameter, regardless of flame speed, it is possible to prevent the passage of flame completely.

Prevent an open fire from spreading Confine the flame within an enclosed location Protect volatile mixtures and chemicals from igniting Stop an explosive event from spreading to other areas Stop the flame travelling at a subsonic speed. Line heaters, glycol dehydrator reboilers, and process heaters Fuel storage tanks Storage cabinets for paint, and other flammable substances. These are so called because they are designed to protect systems in which a flame may start within a container whose cross sectional area is somewhat larger than the flame arrestor element or the vent pipe and the desire is to prevent the flame leaving the container.

They may be simply an element, an end-of-line arrestor or an in-line arrestor. Extreme care must be taken when considering such a situation as it is not possible to predict the conditions that the flame arrestor will have to handle because the volume of hot gases passing through the arrestor will exceed the volumes produced for conventional in-line arrestor flame testing. Although the conditions will tend to produce a confined deflagration it is possible that an arrestor that has been satisfactorily tested under confined deflagration arrestor conditions laid down in a product standard will not be satisfactory.

Therefore, the only solution to ensure total confidence in the product specified is to test it under actual or simulated operational conditions. Liquid product flame arrestors trap some of the liquid flowing in a pipe so that the gases may bubble through it but any flame is extinguished. Hydraulic arrestors contain water whose level is automatically maintained.

Similarly gases may bubble through it but any flame would be extinguished. This technique is particularly suited to a dirty gas flow with particulate matter entrained within it. Tags: deflagration detonation flame arrestor. Why Use a Flame Arrestor? Flame Generation and Types If any flammable mixture of vapor or gas comes in contact with an ignition source, a flame front will develop.

This flame will burn through the vapor or gas until: The supply of fuel vapor or gas is consumed. The heat necessary to sustain combustion is removed. The oxygen concentration becomes either too high or too low to allow continued burning. Deflagration If a flame front is propagating at a speed less than the speed of sound in the vapor, it is known as deflagration. Unconfined Deflagration An unconfined deflagration occurs when there is an ignition of a flammable atmosphere outside a container or other process equipment.

Confined Deflagration A confined deflagration occurs when there is an ignition of a flammable atmosphere inside a pipeline, container or other process equipment. Detonation A detonation occurs where a flame travels along a pipe, usually at supersonic velocities and is combined with a shock wave. Overdriven Detonation If a flame front is propagating at a speed in excess of the speed of sound in the vapor, it is known as overdriven detonation.

Flame Arrestors Working Principle Flame arrestors operate on the principle of removing heat from the flame as it attempts to travel through narrow passages with walls of metal or other heat-conductive material. Types of Flame Arrestors All flame arrestors are designed to allow gases or liquids to pass through while preventing flames or sparks from creating an explosion or expanding into a larger fire.

End-of-Line Flame Arrestor End-of-line flame arrestors are fitted to the end of a pipe line or exit to a vessel to prevent flames from entering, and not, as is sometimes believed, to prevent the flame exiting the pipe or vessel.

In-Line Flame Arrestor In-line flame arrestors are fitted in piping systems to protect downstream equipment. This construction produces a matrix of uniform openings that are carefully constructed to quench the flame by absorbing the heat of the flame.

This provides an extinguishing barrier to the ignited vapour mixture. Under normal operating conditions the flame arrester permits a relatively free flow of gas or vapour through the piping system. If the mixture is ignited and the flame begins to travel back through the piping, the arrester will prohibit the flame from moving back to the gas source.

The other major category consists of in-line flame arresters, also known as deflagration and detonation flame arresters. Speaking non-technically, deflagration means rapid burning, and detonation means explosion. These units are installed in pipes to prevent flames from passing. Most in-line flame arrester applications are in systems which collect gases emitted by liquids and solids.

These systems, commonly used in many industries, may be called vapor control systems. The gases which are vented to atmosphere or controlled via vapor control systems are typically flammable. If the conditions are such that ignition occurs, a flame inside or outside of the system could result, with the potential to do catastrophic damage.

Exposed Side 2. Protected Side 3. Flame stabilized on arrester element 4. Flame arrester element absorbs and quenches flame front 5. One variety of vapor control systems is called vapor destruction systems.

Included are elevated flare systems, enclosed flare systems, burner and catalytic incineration systems, and waste gas boilers. Another type of vapor control system using in-line flame arresters is vapor recovery systems. Included here are vapor balancing, refrigeration, adsorption, absorption, and compression systems. However, in-line flame arresters are sometimes used in end-of-line applications.

For instance, an in-line unit may be mounted below a tank vent Valve on a liquid storage tank. The Valve reduces emissions and product loss, while the flame arrester protects the tank from flames in the atmosphere during venting of flammable gases. Selecting in-line flame arresters The various dynamic states explained earlier for confined flames can be very dangerous for a process system due to the tremendous energies associated with detonation pressure and flame velocity.

Things happen fast and can turn catastrophic. These multiple dynamic states increase the challenge of providing a flame arrester product or products which stop the flame and withstand the enormous pressures caused by explosions within the confined piping. The very wide range of possible behavior for a confined flame causes two particular problems for flame arrester products. First, the high-pressure deflagration and stable detonation states have very stable kinetics of burning, and the flame is moving very fast.