Among the various types of sensors, explosion-proof sensors are one of the more special ones, which are characterized by reliable operation, easy installation and use, as well as high explosion-proof level. Today’s explosion-proof sensors are widely used in many industrial fields. In fact, there are many types of explosion-proof type, today to introduce a variety of explosion-proof type. The first to be introduced is the intrinsically safe type. Intrinsically safe type “i” (intrinsically safe electrical equipment and its associated equipment) refers to the specified test conditions, normal operation or the specified fault state of electrical sparks and thermal effects can not ignite the specified explosive gases or vapors of the circuit. Intrinsically safe equipment and equipment related to the intrinsically safe part is divided into ia and ib two kinds. ia: refers to the normal operation + a fault + any combination of two faults can not cause ignition of electrical equipment. ib: refers to the normal operation + a fault can not be caused by the intrinsic safety of the ignition of electrical equipment. It can be seen that the ia-type explosion-proof grade sensor is higher than the ib-type explosion-proof grade sensor. The second type: explosion-proof type “d”. Electrical equipment with an explosion-proof enclosure. Explosion-proof sensors can withstand the internal explosion of combustible mixtures that have entered the interior of the enclosure without damage, and through any joints or holes in the enclosure will not ignite by one or more gases or vapors formed by the external explosive environment. The third type: increased safety type “e”. It means that no arc or spark will be generated under normal operating conditions. Electrical equipment by taking some additional measures to increase its degree of safety, to prevent its internal and external components may appear dangerous temperature, arc and spark possibility of explosion-proof type. It does not include equipment that generates sparks or arcs under normal operating conditions. Type IV: Oil-filled type “o”. It means that all or part of the components are immersed in oil, so that the equipment can not ignite the explosive mixture above the oil surface or outside the shell. The fifth type: sand-filled type “q”. Shell filled with sand material, so that it is in the specified conditions of use shell generated arc, propagation of the flame, shell wall or the surface of the sand material overheating can not ignite the surrounding explosive mixture. Sixth: pouring seal type “m”. Equipment or its components poured in a potting agent so that it can not ignite the surrounding explosive mixture under normal operation and recognized overloads or recognized failures Type 7: Composite. Refers to a variety of explosion-proof way aggregate. Explosion-proof sensors in the use of the sensor’s enclosure must be effectively grounded. Like the explosion-proof type explosion-proof sensors used in hazardous locations, the sensor’s shell must be tightened. In order to ensure the safety of use, do not allow the sensor cover to be opened when the power is energized. Also ensure that the sensor cable lead outlet has a good seal.