What is a flameproof instrument

Explosion proof, also known as pressure resistant explosion-proof, seals instrument components that can ignite explosive mixtures in a casing that is particularly sturdy, capable of withstanding the explosive pressure of internal explosive mixtures and preventing the transmission of explosive mixtures to the outside of the casing. That is to say, explosions may occur inside the casing of explosion-proof instruments, but they will not spread to the outside of the casing. Therefore, the joint surfaces of various components of this instrument, such as the number of thread turns on the instrument cover, thread accuracy, zero point, the gap between the range adjustment screw and the case, the gap between the detection and conversion components of the transmitter, and the wire port, all have strict explosion-proof requirements.

Explosion proof instruments are relatively simple and do not require associated equipment such as safety barriers, except for being bulky. But before opening the watch cover, the power must be turned off first, otherwise if sparks are generated, it will be exposed to the atmosphere and pose a danger.

What is an intrinsic safety instrument

Essentially safe instruments are also known as safety spark instruments. Its characteristic is that the sparks generated by the circuit and system, as well as the temperature reached, will not ignite explosive mixtures in both normal and fault states of the instrument. Its explosion-proof is mainly achieved through the following measures:

①The instrument circuit is composed of new integrated circuit components and operates at lower operating voltages and currents;

②Separate the circuits in hazardous and non hazardous areas with safety barriers to limit the energy transmitted from non hazardous areas to hazardous areas;

③The connecting wires of the instrument shall not form excessive distributed inductance and distributed capacitance to reduce energy storage in the circuit.

The explosion-proof performance of this safety type instrument is not achieved through external measures such as ventilation, inflation, oil filling, and explosion-proof, but rather through the circuit itself, making it inherently safe. It can be applied to all hazardous areas and all explosive gas and vapor mixtures, and can be repaired and adjusted with power on. However, it cannot be used alone and must be combined with intrinsic safety related equipment (safety barriers) and external wiring to form an intrinsic safety circuit in order to perform explosion-proof functions.