Explosion-proof positive pressure box is an electrical equipment with explosion-proof function. Through the intelligent control system and pressure control system, it introduces clean and safe compressed air into the box to form a micro-positive pressure inside the box, preventing the entry of dangerous gases and dust from the outside, so as to achieve the purpose of explosion-proof.

Its main characteristics and functions include:

1. When the air pressure is higher than 1000Pa, the pressure relief valve will automatically open the exhaust valve to automatically adjust the internal air pressure to ensure that the product is not deformed or damaged by high-pressure impact.

2. When the air pressure is lower than 50Pa, the automatic control system will automatically send out an alarm and output an alarm signal. It is necessary to adjust the internal pressure. When the air replenishment is successful, it will automatically return to normal. Otherwise, the system can be set to automatically cut off the power when necessary (According to the national standard, the low-pressure alarm in Zone 1 requires cutting off the power supply of the cabinet, while the low-pressure alarm in Zone 2 can not cut off the power supply).

3. Only when the air pressure of the cabinet meets the specified pressure requirements, the positive pressure purging control system will effectively ventilate the cabinet (Zone 1 requires the replacement of 7 times the free space of the cabinet, and Zone 2 requires the replacement of 5 times the free space of the cabinet). When the effective ventilation is completed, a signal is provided to supply power to the cabinet.

4. The working air pressure inside the positive pressure cabinet is generally 50Pa ≤ P ≤ 1000Pa.

5. The protection device is complete, and it is equipped with a ventilation and power transmission interlock device. Only after the specified ventilation time is reached can the power be automatically transmitted, and it has high and low voltage automatic audible and visual alarm, pressure lower limit, automatic power-off when the door is opened, emergency manual power-off and other safety interlock protection.

6. The sealing performance is reliable, and multiple sealing protections are adopted, with a long pressure holding time and low operating cost.

7. The interior of the product can be equipped with detection instruments, analysis instruments, display instruments, low-voltage electrical appliances, frequency converters, soft starters or computer control systems, and can be used as a central signal processing system and a central control system.

The application scope of the explosion-proof positive pressure box includes:

1. Hazardous areas with explosive gas mixtures: Zone 0, Zone 1, and Zone 2. Among them, Zone 0 is an environment where explosive gas mixtures appear continuously or for a long time; Zone 1 is an environment where explosive gas mixtures may appear during normal operation; Zone 2 is an environment where explosive gas mixtures cannot appear during normal operation or only exist for a short time even if they appear. In the actual design process, Zone 1 rarely exists, and most cases belong to Zone 2.

2. Explosive gas mixtures: IIA, IIB, IIC.

3. Temperature groups: T1 - T6.

4. It can be used indoors and outdoors (IP55).

5. Flammable dust environments Zone 20, Zone 21, and Zone 22.

In terms of structure, explosion-proof positive pressure boxes usually have different structural forms, such as box type, console type, and cabinet type, etc. The box type is generally welded with steel plates and surface sprayed, with the front door for operation; the cabinet frame of the console type and cabinet type is welded with standard profiles and surface sprayed. Each joint surface undergoes special sealing treatment, with the front door for operation and the rear door for maintenance. The steel plate material generally selects cold-rolled steel plate GB710-88, and stainless steel material can also be used according to requirements. According to the air intake method, it can be divided into continuous purging type and leakage compensation type. The continuous purging type continuously supplies air without interruption and has good heat dissipation function; the leakage compensation type supplies air intermittently and has low air consumption.

When manufacturing an explosion-proof positive pressure box, users need to provide a complete electrical system diagram and a list of internal materials for the control system. Explosion-proof positive pressure boxes produced by different manufacturers may have certain differences in specific functions, parameters, and structures. When selecting and using them, it is necessary to consider according to actual needs and relevant standards, and ensure that they are installed, operated, and maintained by professionals.