1、 Application scenarios of explosion-proof mobile phones
Explosion proof mobile phones are mobile phones that can be used in flammable, explosive, smoke and other natural environments. All explosion-proof mobile phones are attached with Ex explosion-proof certification mark, which indicates that the product has been verified according to the national explosion-proof testing center, and can be used in special flammable gas natural environment, and is applicable to petroleum industry, chemical plants, natural gas and other flammable and explosive sites.
2、 Basic principle of explosion-proof mobile phone
Generally, mobile phones will become open fire due to high frequency radio waves, friction sparks, flame caused by ignition of machines and equipment, explosion of rechargeable batteries and other risk sources. Because combustible compounds are commonly found in the manufacturing, production, processing, storage and transportation sites of manufacturing industries such as coal, petroleum industry, chemical plants, textiles, grain and oil processing, mobile phones in such sites generally become a strong source of safety production accidents, and in case of an explosion accident, great harm will be caused;
Explosion proof mobile phones deal with the problem of open fire in many aspects. There is no difference in the appearance design between explosion-proof mobile phones and ordinary mobile phones, but they are quite different from ordinary models in terms of raw materials and physical characteristics. Generally, V0 flame retardant and fireproof materials are used. The manufacturer has selected a variety of explosion-proof technologies, such as intrinsically safe power circuit, limiting the maximum ambient temperature of the enclosure, and selecting a "dust tight" or "anti fouling" enclosure to limit the incoming smoke and dust, so as to avoid ignition of combustible compounds and promote safe operation of explosion-proof mobile phones in the risk natural environment.
3、 How to select explosion-proof mobile phones
The company should know how to select the explosion-proof mobile phone suitable for its own company. When selecting explosion-proof mobile phones, it is necessary to first identify the types of combustible chemicals in the natural environment, and then divide the risk site according to the difference of vapor or dust.
1 Flammable chemicals are classified into Class III:
Class I: coal mine methane gas; Class II: combustible vapor compounds (including steam and mist); Class III: combustible smoke (chemical fiber or floating flocs).
2 Definition of risk site
It is a measure of the specific risk probability of the region, thus requiring the available flameproof type. Below is the classification of risk areas classified by the International Electrotechnical Commission/European Electrotechnical Commission
Zone 0: Flammable and explosive vapors are stored all the time or for a long time; Areas with continuous risk factors exceeding 1000 hours/year;
Zone 1: combustible gas will be generated or stored in the whole process of the instrument panel's proper operation; Areas with risk factors for 10~1000 hours/year intermittently;
Zone 2: In general, there is no combustible gas and even if it is sometimes generated, its storage time is very short; Areas with 0.1~10 hours/year of risk factors in case of safety accidents;
3 Temperature class
It is the maximum ambient temperature of electrical equipment (assuming the operating temperature is 40 ℃) related to the ignition temperature of the vapor, and the ignition kinetic energy is irrelevant to the ignition temperature. All flammable vapors and their grades are listed in the first part of the specification BS5345.
Class I: coal mine electrical equipment;
Class II: all electrical equipment used in natural environment of combustible gas except for coal mine and coal mine.
Class II can also be divided into Class IIA, Class IIB and Class IIC. The machinery and equipment marked with Class IIB can apply to the application standards of Class IIA machinery and equipment; IIC is applicable to the application standards of IIA and IIB.
Class III: electrical equipment in natural environment with combustible smoke and dust except for coal mine.
Class IIIA: flammable floating flocs; Class IIIB: non-conductive dust; Class IIIC: conductive dust.
Maximum ambient temperature: the maximum temperature of all components of electrical equipment that will cause ignition in the surrounding flammable natural environment when the electrical equipment is working under the worst operating standard within the required range. The maximum ambient temperature shall be less than the flammable temperature.
For example, if the ignition temperature of flammable vapor in the natural environment of the explosion-proof controller is 100 ℃, the maximum ambient temperature of all components of the controller should be less than 100 ℃ under the most extreme working attitude.
Electrical equipment for flammable natural environment is classified as T1-T6 according to its maximum ambient temperature
To sum up, the company can select explosion-proof mobile phones matching the explosion-proof grade according to its own conditions.
4、 Common problems of explosion-proof mobile phone application
(1) When purchasing a new explosion-proof mobile phone, it is necessary to determine whether the content of the explosion-proof sign is consistent with the regulations, whether the model and specification of the explosion-proof rechargeable battery (removable rechargeable battery) are consistent with the battery model on the label sticker on the shell, whether the rubber seal of each socket is damaged or deformed, and whether it is a reasonably sealed socket;
(2) Explosion proof mobile phones are not allowed to be used in flammable natural environment if they are physically damaged, or they may easily cause explosion or fire accidents;
(3) When installing the explosion-proof rechargeable battery, handle it with care and avoid rolling and collision, or it will endanger the explosion-proof characteristics of the rechargeable battery. Keep the label of the rechargeable battery clear and detailed; Make sure that the contact point is cleaned and there is no dirt in the compartment. Put the rechargeable battery in place. Make sure that the sealing ring near the rechargeable battery compartment is leveled in time. After the rechargeable battery cover is put in place, tighten it with screws. Each screw should be of even strength, not too loose or too tight. It is appropriate to think that the rubber ring is shrunk by 8;
(4) Explosion proof mobile phones should not be used in areas beyond the required explosion-proof grade, otherwise safety production accidents will occur because the explosion-proof grade does not meet the requirements;
(5) It is not necessary to replace the battery of explosion-proof mobile phone in the natural environment of flammable vapor, otherwise, it will cause explosion or fire accident due to touch spark discharge caused by static induction during disassembly;
(6) The working temperature of explosion-proof mobile phone application is - 20 ℃～ ＋ 40 ℃, and the standard air pressure is 80Kpa ～ 110Kpa;
(7) During the application of explosion-proof mobile phones, it is necessary to maintain the identifiability and consistency of the labels. In addition, it is necessary to ensure the consistency of the information content labels of the devices on the mobile phones, so as to clarify the unique real identity of the devices;
(8) The explosion-proof mobile phone does not need to be charged by the battery in the natural environment of flammable vapor, but should be charged by the battery of the charging head produced by the manufacturer;
(9) When the explosion-proof mobile phone has a common fault or is suspected to have a common fault, it cannot be used again. Contact the manufacturer immediately for maintenance and metrological verification. It is not necessary to disassemble and assemble the explosion-proof mobile phone by all means. The original design scheme and structure of the mobile phone hardware will be changed by independent disassembly and assembly, resulting in invalid explosion-proof type;
(10) Strictly implement the requirements of explosion-proof certificate, and apply the external equipment on mobile phones to plug in the machine equipment;
(11) It is not necessary to store explosion-proof mobile phones in damp, cold and high temperature areas for a long time.