Electrical control cabinets are mainly used in petrochemical, electronic industry, medical, rubber products, spraying, automobile manufacturing, printing and other industries. For example, in the process of oil extraction, due to volatilization, release and leakage, corresponding flammable gas and steam will be formed, which will be mixed with air and mist to form an explosive gas environment. Under high temperature, sparks, arcs and other reasons, the gas ignites, causing serious disasters such as explosions.

PLC electrical control cabinet refers to the principle that the protective gas pressure in the positive pressure shell is higher than the external atmospheric pressure, which can effectively prevent the external explosive gas from entering the shell or dilute the explosive gas concentration released by the shell to below the explosion limit. The electrical control cabinet is divided into positive pressure ventilation type and positive pressure compensation type. The principle of positive pressure ventilation is that the protective gas flows through the positive pressure housing for a long time and always maintains the same flow, so that the pressure of the positive pressure housing is kept within the normal pressure range. However, positive pressure compensated models do not require continuous ventilation. The control system detects the pressure of the positive pressure housing at any time, and the solenoid valve effectively controls and protects the inflow and outflow of the gas.

(1) The function of the wind control system is to effectively ensure that the positive pressure explosion-proof control cabinet can be ventilated before use, and the next operation can be performed after the ventilation is completed. This process, called a delay system, is a mandatory step to guarantee explosion-proof performance.

(2) Pressure monitoring system: monitor the pressure of the positive pressure shell, analyze and process the pressure data by using the pressure sensor, reflect the pressure value and transmit it to the distributed control system.

(3) Alarm system: The output control signal is analyzed and processed by the automatic continuous tracking monitoring system and the pressure monitoring system, and then an execution system is formed, including the positive pressure value in the positive pressure shell is lower than 50pA or the forced automatic power off of the ultra-high pressure shell or Alarm display function.

(4) Automatic continuous tracking and monitoring system: pressure collection, monitoring, ventilation, alarm, monitoring and abnormal pressure management, monitoring, decentralized control system.

The principle of positive pressure ventilation electric control cabinet is that the protective gas will not flow out of the positive pressure shell for a long time, and always maintain the same flow rate, so that the pressure of the positive pressure shell is always kept within the normal pressure range. Positive pressure compensated models do not require continuous ventilation. The control system detects the pressure of the positive pressure housing, and the solenoid valve effectively controls the inflow and outflow of the protective gas.