Shenhai Explosion-Proof
Recently, there has been a surge in customer inquiries about explosion-proof positive pressure cabinets. Some basic queries seem to be unclear due to the specialized nature of the subject. In response to this, let’s share some essential knowledge about explosion-proof positive pressure cabinets.
1. Definition
An explosion-proof positive pressure cabinet is a type of explosion-proof enclosure featuring an internal positive pressure control system that automatically adjusts its internal pressure. These cabinets are primarily made of stainless steel 304 or steel plate and are customized in size based on customer requirements.
2. Gas Environments
Designed for hazardous locations with explosive gas mixtures: Zones 0, 1, and 2. They are applicable in environments with explosive gases found in petroleum, chemical, pharmaceutical, paint, and military facilities.
3. Scope of Application
Primarily used in petroleum and chemical industries, as well as military installations, they are generally suitable for Classes IIA, IIB, IIC, and environments with T1 to T6 explosive gases or vapors. Their usage is intended for areas with an altitude not exceeding 2000 meters and atmospheric temperatures ranging from -20°C to +60°C. Internal components can accommodate various standard electrical devices, such as meters, circuit breakers, AC contactors, thermal relays, inverters, displays, etc., as required by the design specifications.
4. Structural Features
There are three main structural designs: box type, piano key type, and upright cabinet type. The box type is usually made of stainless steel 304, featuring a brushed or mirrored finish, with access to internal components via the front door. The other two, piano key and cabinet types, employ similar welding processes, with a brushed or powder-coated finish. All join surfaces of the enclosure undergo explosion-proof sealing.
5. Control System
The control system is a highly advanced electrical setup. It operates when the internal working pressure of the cabinet ranges between 50Pa and 1000Pa. When the pressure exceeds 1000Pa, the system’s pressure relief valve automatically opens the exhaust device until the pressure drops below 1000Pa, protecting the internal electrical components from damage. If the pressure falls below 50Pa, the system triggers an alarm, with flashing lights and sound to alert on-site personnel, resuming normal operation once re-pressurization is successful.
6. Technical Parameters
1. Explosion-proof grade: ExdembpxIICT4;
2. Rated voltage: AC380V/220V;
3. Protection level: Options include IP54/IP55/IP65/IP66;
4. Cable entry: Customized according to client requirements, such as top-entry/bottom-exit, top-entry/top-exit, etc.
7. Usage Experience
Based on years of manufacturing experience, electricians should operate according to the provided electrical schematics. Regular replacement of aging internal components is recommended, typically every two years. The ventilation system should be frequently cleaned. Particularly in harsh operational environments, external seals should be replaced annually to ensure the normal functioning of the gas supply system. If the gas supply system is damaged, it is advised to purchase a new set from the supplier to avoid incompatibility issues.
This comprehensive guide on explosion-proof positive pressure cabinets aims to enhance understanding and provide valuable insights for those interested in this technology.