According to the mechanism of occurrence, spontaneous combustion can be roughly divided into the following seven types:
Oxidation and heat spontaneous combustion. An unsaturated organic compound containing a double bond in a molecule, such as an oil-impregnated substance, lignite, or the like, has a characteristic of being able to absorb oxygen in the air and undergo partial oxidation, and generates a large amount of oxidation reaction heat. If it is accumulated, the temperature in the reaction system is increased. It will rise and reach spontaneous combustion at the point of self-ignition. Some substances with low self-ignition points, such as yellow phosphorus, aluminum alkyl, phosphine, reduced iron, etc., react rapidly with oxygen in the air at normal temperature to cause combustion.
It is divided into liberation heat and spontaneous combustion. At room temperature, substances that can be separated from heat, such as nitrocellulose, celluloid and nitroglycerin, do not require external oxygen to participate in the reaction, but in good heat storage conditions, due to the oxygen content in the molecular structure. Next, the temperature gradually rises and finally spontaneous combustion occurs.
The polymerization exotherms spontaneously. Some units used in chemical production, such as vinyl acetate, acrylonitrile, etc., have strong chemical activity. In the reaction process of polymerizing into high molecular polymers, most of them are accompanied by exothermic heat, and the temperature needs to be strictly controlled in the production process. If the heat of polymerization cannot be emitted outside the system, the polymerization rate will increase sharply, and a flushing or spontaneous combustion explosion will occur.
Adsorption exothermic spontaneous combustion. Materials such as carbon powder, such as activated carbon and charcoal, have high activity when they are just finished or wind-pulverized. When exposed to air, they will physically or chemically adsorb various gas components in the air. In addition to generating heat of adsorption, the adsorbed oxygen will also react with carbon to further heat. If the heat storage conditions are good, the heat of adsorption and the heat of oxidation together cause the temperature of the substance to rise to the point of spontaneous combustion and spontaneous combustion occurs.
Fermentation exothermic and spontaneous combustion. Some plant fiber materials such as straw, seed cotton, leaves, sawdust, etc., cause fermentation due to the action of internal microorganisms or enzymes, producing unstable decomposition products, which are highly reactive and contain unsaturated substances, and are oxidized in the air. The heat should be released so that the internal temperature continues to rise until it reaches the auto-ignition temperature and spontaneously ignites.
The active substance spontaneously ignites in water. Some active substances, such as alkali metals, zinc powder, insurance powder, hydrolyze when exposed to water or moisture in humid air, produce flammable gases and release heat, causing spontaneous combustion.
The substance is mixed and spontaneously ignited. The strong oxidant is mixed with the strong reducing agent, the strong acid is mixed with the oxidizing salt or the substance is mixed to produce unstable products with decomposing explosive properties or strong oxidizing properties, which can be burned or exploded.
Precautionary measures for spontaneous combustion:
1. Seriously investigate the spontaneous combustion characteristics and thermal insulation properties of the stored materials. For substances that are prone to chemical and physical reactions and generate heat, it is necessary to check in detail the new materials and substances that are not well resolved, and if necessary, they can be confirmed by experiments and other methods to take appropriate storage measures. For powdery, fibrous or porous substances with good thermal insulation and thermal insulation properties, it should be clearly understood before storage so as to adopt proper accumulation method, accumulation amount and isolation method when storing.
Second, the implementation of strict temperature measurement management. The precursor of spontaneous combustion is spontaneous combustion and has a long period of ignition induction (ignition delay or induction period). Therefore, the substance with spontaneous combustion characteristics should be continuously measured and recorded in the storage, and the temperature and humidity of the substance itself and the environment should be recorded. Take measures such as squatting and ventilation in time.
Third, take appropriate decentralized cooling measures. For substances that are prone to heat, they should be stored in a place that can avoid the sun's rays or in a cold and dark warehouse. Disperse storage should be adopted, and measures such as frequent dumping, limited accumulation, improved accumulation, and desiccant should be taken to improve ventilation. Ventilate and create good heat dissipation conditions. For the risk of being heated, a water-cooled sprinkler is required to perform the necessary cooling.
Fourth, to prevent mixed contact. For substances that are prone to chemical exotherm after mixed contact, avoid mixing, mixing, mixing, and not too close to other combustible materials during storage. Avoid direct contact with combustible oil polymers, resins, paper, Wood, etc.
5. Some substances that cause deterioration or chalking during long-term storage are also prone to spontaneous combustion and should be burned off as soon as possible.
Frequently dumping, limited accumulation, improved stacking methods, placing desiccant and other measures, do a good job of ventilation and ventilation, and create good heat dissipation conditions. For the risk of being heated, a water-cooled sprinkler is required to perform the necessary cooling.
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About Material
The tape measure is made of ABS case, PVC coated fiberglass. All the materials are eco-friendly, which pass ROHS and EN-71 tests. The lead content is less than 5ppm.
About Case Color
Case colors can be customized according to pantone code. We have stock for standard color, white and black.
We can make metal silver color and transparent color too.
About Custom Logo
Custom logo is available.For 1-2colors logo, we will use silk printing
For full color logo, we will print it with heat transfer printing ,
And we also make normal sticker or epoxy plate logo sticker for single color or full color logo
For PU or real leather tape measure, we can make emboss logo
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About Tape Colors
Standard tape colors are in white and black
We can make pink, green or other colors.
Full color design is available too.
About Tapeline Size
The standard length is 150cm/60inch and 100cm/40inches
We have longer one in length of 180cm/72inch and 200cm/79inch, and the maximum length is 214cm.
The maximun length for the square shape item is 1.5M/60inch,
Tape width is 7.5mm.
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