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This animation explains the science behind our FMD. Proof of Concept – Practical Demonstration When the Container 2 Rich (C2R) designed FMD is wetted with gasoline, it traps & retains enough gasoline in its openings to take the mixture inside the FMD above the UFL (upper flammability limit). The sparker can’t ignite the too rich mixture inside the FMD because the atmosphere there cannot ignite or burn. Only when the sparker is placed at the very top of the FMD does the atmosphere at that position have enough air to burn. This demonstrates the C2R concept works very well as even a spark generator cannot ignite the noncombustible atmosphere inside the FMD. So a flame or spark trying to enter the FMD will be snuffed by the noncombustible mixture within the patented C2R FMD. |
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Flame Arrestors do not control mixture inside To demonstrate flame arrestors used in safety cans work differently from the C2R FMD design, we wet both of them in gasoline and attempt to ignite the atmosphere inside them. Both metal flame arrestors ignite almost immediately as the fuel to air mixture inside them is combustible. This does not mean they are ineffective, they simply work in a different way (quenching) to stop a flame or spark from advancing into the interior of a can. (Please see video above.) The liquid gasoline left on both FA's screen surface takes under half a minute to burn off. |
The Science behind our FMD
How our FMD works:
By retaining liquid gasoline in its walls (see trapped gas on the video page), the C2R design influences the mixture ratio inside the FMD cup to stay at or above the upper flammability limit (UFL). The closer a flame or spark gets to the cells filled with liquid gasoline, the richer the mixture. Combustion is not possible inside such a small space that is lined with gasoline. This creates a very effective barrier to the interior of the gas can.
Combustion requires three things: fuel, air & ignition. However liquid fuels like gasoline need a proper mixture of gasoline and air to burn. The extremes are explained in more detail below, but simply put- if there isn’t enough or if there is too much gas in the fuel to air mixture; it won’t burn. So let’s talk about possible fuel to air mixtures:
Fuel to Air Mixtures:
Φ – (Normally represented by Greek letter phi)
In relating to fuels and fire, a stoichiometric mix represents the perfect balance of air to fuel. In this perfect case, the combustion event leaves no excess fuel nor air as both are fully consumed. Combustion may occur outside of this perfect balance- a combustible mixture does not have to be perfect- it can be a bit lean of fuel as well as fuel rich and still be combustible. However- at some point combustion is not possible if the mixture is too fuel lean or too fuel rich
Flame Arrestors:
Flame arrestors stop flames or a spark with an entirely different method. Metal fuel safety cans in our industry use a small cup made of steel screen called a flame arrestor. It stops a flame’s progression into the interior of the fuel can using thermal quenching. Quenching lowers the temperature of the flame by absorbing and dispersing its heat throughout the screen. Flame arrestor quenching technology is used in many roles and has been around since the early 1900's. It is an entirely different approach than C2R.
Why not use a flame arrestor in a plastic fuel can? The possibility of static electricity. While it is a low probability, static electricity may be generated by pumping gas quickly through a metal screen if conditions are right. The screens can be grounded properly with a metal safety can. They cannot be grounded properly if in a typical plastic fuel can.
By retaining liquid gasoline in its walls (see trapped gas on the video page), the C2R design influences the mixture ratio inside the FMD cup to stay at or above the upper flammability limit (UFL). The closer a flame or spark gets to the cells filled with liquid gasoline, the richer the mixture. Combustion is not possible inside such a small space that is lined with gasoline. This creates a very effective barrier to the interior of the gas can.
Combustion requires three things: fuel, air & ignition. However liquid fuels like gasoline need a proper mixture of gasoline and air to burn. The extremes are explained in more detail below, but simply put- if there isn’t enough or if there is too much gas in the fuel to air mixture; it won’t burn. So let’s talk about possible fuel to air mixtures:
Fuel to Air Mixtures:
- Stoichiometric:
Φ – (Normally represented by Greek letter phi)
In relating to fuels and fire, a stoichiometric mix represents the perfect balance of air to fuel. In this perfect case, the combustion event leaves no excess fuel nor air as both are fully consumed. Combustion may occur outside of this perfect balance- a combustible mixture does not have to be perfect- it can be a bit lean of fuel as well as fuel rich and still be combustible. However- at some point combustion is not possible if the mixture is too fuel lean or too fuel rich
- LFL (about 1.4%)
- UFL (about 7.6%)
Flame Arrestors:
Flame arrestors stop flames or a spark with an entirely different method. Metal fuel safety cans in our industry use a small cup made of steel screen called a flame arrestor. It stops a flame’s progression into the interior of the fuel can using thermal quenching. Quenching lowers the temperature of the flame by absorbing and dispersing its heat throughout the screen. Flame arrestor quenching technology is used in many roles and has been around since the early 1900's. It is an entirely different approach than C2R.
Why not use a flame arrestor in a plastic fuel can? The possibility of static electricity. While it is a low probability, static electricity may be generated by pumping gas quickly through a metal screen if conditions are right. The screens can be grounded properly with a metal safety can. They cannot be grounded properly if in a typical plastic fuel can.