Prior to installation, system designers working in corrosive or hazardous environments need to expertly analyze how to safely deploy electronics.
Considerations for the manufacturing area’s classification and division for components such as LCDs, touch screens, HMI, computers and various other hardware is crucial. A system designer may be able to procure controllers and electronic equipment that are rated for a hazardous area and can be deployed, in such areas, out of the box. However, these systems are generally very expensive to repair or replace in the event of any type of failure. Alternative options for installing non-hazardous area electronics include using a purged computer enclosure.
Purged computer enclosures offer a safe, temperature-regulated, and pressurized environment for costly electronics. The purge system is often regulated by a low-maintenance vortex cooling unit, which utilizes clean air and creates an “office-like” environment inside of the enclosure.
3 Considerations for Purged Computer Enclosures
- Enclosure Construction: Purged enclosures require a certain level of protection that can be afforded in either a NEMA 4X or NEMA 4 cabinet. Stainless steel enclosure material (usually 12 gauge), that can resist corrosive areas, may be required. For less extreme environments, a painted steel NEMA 4 enclosure design may be satisfactory. Modifications, such as additional latches to ensure a tight seal, may also be required by the enclosure manufacturer.
Input Devices: Many providers of purge systems will offer devices such as keyboards and pointing devices (hula point pointing device can be integrated into the keyboard or as a standalone option) that are available with intrinsically safe or non-incendive ratings. These peripherals are designed for harsh or hazardous working conditions and combine the ruggedness that is required with the feel and action of a regular, standard keyboard. The requirements for the area’s classification and division will dictate the use of an intrinsically safe or non-incendive device. These units are robust and are connected via barriers in the protected enclosure.- Maintenance: Accessing the electronics inside of a purged enclosure is inevitable. With that being said, maintenance personnel need to be made aware they simply cannot open the enclosure without taking certain safety precautions. It is always imperative for personnel to check the area to determine if hazardous gases are present. If hazardous gases exist, the system operator must shut down the equipment, before accessing electronics inside of the computer enclosure.
As a system designer, the best practices for specifying electronics and computer enclosures in hazardous environments include checking the systems overall rating (classification and division), as well as research into the manufacturer providing the system solution. Always choose a manufacturer that has extensive experience of how to safely enclosing electronics in a hazardous area.
Obviously, if a company chooses the wrong solution, the results could be catastrophic.
