A flameless flam heater , or FRH , is a water-activated water heater exothermizer supplied with Meals, Ready-to-Eat (MREs), used to heat food. The US military specification for heating required that it be able to raise the temperature of an 8-ounce (226.8 g) dish with 100Ã, ° F (56Ã,  ° C) in twelve minutes, and that it has no visible flame.
The ration heater contains a fine-grained magnesium metal, mixed with a small amount of iron, and table salt. To activate the reaction, a small amount of water is added, and the boiling point of water is quickly achieved as the reaction progresses.
Video Flameless ration heater
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The heater ration generates heat in the electron transfer process called the oxidation reduction reaction. Water oxidizes magnesium metal, according to the following chemical reactions:
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This reaction is analogous to iron that is rusted by oxygen, and continues at the same slow rate, which is too slow to produce heat that can be used. To accelerate the reaction, metal particles and table salt (NaCl) are mixed with magnesium particles.
Iron and magnesium metals, when suspended in electrolytes (such as brine), form galvanic cells - "batteries" - which can generate electricity. When water is added to the heating ration, it dissolves the salt to form a salt water electrolyte, thus converting each magnesium particle and iron into a small battery. Because of the magnesium and iron particles touched, they become thousands of short-burning, rapidly burning batteries, producing heat in a process called "Supercorroding Galvanic Cells" patent holders.
The Truetech-brand Ride Raut Heater uses 7.5 grams of magnesium-iron alloy powder, which consists of 95% magnesium and 5% heavy iron, 0.5 grams of salt, in addition to deep filler and anti-foaming agent. After adding 30 milliliters of water, this mixture can heat a meal package of 230 grams to 100 Â ° F in about 10 minutes, releasing about 50 kilojoules of heat energy at about 80 watts.
Maps Flameless ration heater
Limited space hazard
The US Aviation Administration's (DOT) Federal Aviation Administration (FAA) conducted a test and released a report which in summary states "... the release of hydrogen gas from this flameless ration heaters is sufficient to cause potential dangers to passenger aircraft." done on commercial grade 'heating' comprises unclothed flameless heat bags, a bag of saltwater, styrofoam plates/trays, and food in a closed, microwaved/boiled bowl.
See also
- Self-heating can
- Self-heating food packaging
- Active packaging
References
Source of the article : Wikipedia
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