The instrument is composed of flameproof casing, measurement system, electrical contact group, adjustment device and outlet box. The flameproof shell of the instrument has good flameproof performance, so it can effectively withstand the explosion pressure generated by the explosive gas mixture inside the shell due to the influence of sparks or arcs during normal operation. The resulting heat energy can be prevented from spreading smoothly outwards, but can only be slowly diffused outwards along the tiny gaps of the flameproof joints inside the casing. At this time, the instantaneous temperature transmitted to the outside of the casing has been reduced to below the ignition temperature of the explosive gas mixture, so it will not cause detonation.
The working principle of the instrument is based on the elastic deformation of the detection element (the spring tube in the measurement system), which drives the contacts in the electrical contact group to produce corresponding actions (close or open) through mechanical transmission to make the voltage in the pressure control system. The circuit can be turned on or off, so as to realize the purpose of automatic control alarm and on-site indication.
