Thanks to the protection provided by diverse technical measurements, it is nowadays possible to use PCs even under extreme conditions. An explosion-protected PC offers the full functionality of PC technology in Ex areas, without the need for further protection measurements.
The user can choose between three technical solutions for controlling industrial production processes by PC in areas subject to an explosion hazard. These are the „pressurised apparatus“ explosion protection mode, „intrinsically safe“ displays wired to a computer unit outside the hazardous area and explosion-protected PCs. Pressurised apparatus, however, needs a protective enclosure that has to be continuously supplied with protective gas. A gas supply pipeline therefore has to be installed and the pressure controlled permanently by means of an electronic device. If intrinsically safe displays wired to a computer unit outside the hazardous area are installed, additional safety barriers are needed. The wiring for the data transfer has to take the form of intrinsically safe cables.
Flameproof personal computer
With a flameproof-enclosure PC, suitable for explosion hazard area 1, installation and operating costs are reduced and less space is needed. The electronic components of the PC and the display are each accommodated in a separate flameproof enclosure. This two enclosures are screwed together. The patented enclosure for the display is designed to withstand the pressure of a possible explosion, despite its large glass screen. The second enclosure has sufficient space for all the necessary electronic components. The flameproof enclosures comply with the IP 55 degree of protection on the front. The PC is designed for temperatures of 0 to 50 °C. It can be integrated in a stand-alone control enclosure, mounted on a supporting arm or built into a control panel. The intrinsically safe keyboard can either be designed for installation on the front or covered by a protective case.
The explosion-protected PC is equipped with a 14.50 TFT display with XGA resolu-tion, a 64 MB RAM and a hard disc. It can be connected to an Ethernet network (Novell NE 2000-compatible) via a network port. Any standard operating system, such as Windows 95/NT or UNIX, can be used. By connecting the explosion-protected PC to the existing PC network, the complete software functionality can be made available in the explosion hazard area.
Advantages for the user
The explosion-protected PC enables the user to dispense with intrinsically safe wiring and safety barriers outside the explosion hazard area, as well as a continuous supply of protective gas. The user can choose between various types of installation, depending on the circumstances on site. Other special key-boards, for example with large function keys, are also available. The PC installation can thus be tailored to the user’s own specific requirements and optimally integrated on site in the explosion hazard area.
Types of application
Explosion-protected PCs represent the ideal solution for companies in the chemical, pharmaceutical and petrochemical industries, as well as in mechanical engineering firms which manufacture machines and assemblies for use in Ex areas. In the chemical industry, explosion-protected PCs can be used directly on site at the reactor in order to control and document processes online. If no network is available or if special hardware components such as communication cards are needed, a remote station can be supplied. A computer unit is installed outside the explosion hazard area and connected to the flameproof enclosure of the PC display.
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Further information cpp-201