MechChem Africa February 2020

⎪ Products and industry news ⎪

Monitor in recycling plant. monitor, to complex systems with multiple monitors wheredecentralisedindividualcontrolsareconnectedwithacentral control unit via a fibre optic network. Depending on the requirement, compact PLC systems or systems consisting of several interconnected assemblies make up the control system. Where high functional safety is required, redundant CPUs can be installed or, alternatively, PLC control systems in accordance with the required safety level (SIL). A daily automatic self-test is a standard feature of today’s control systems. During this process, the functionality of all drives and sensors fitted on the remote-controlledmonitors is tested. If a fault is found at one of the components, a corresponding error message is sent to the supervising body. This ensures that ‘possibly occurring’ failures are re- ported immediately and can be eliminated before amalfunction during operationoccurs. This functionality significantly increases the reliability and availability of the automated firefighting system, compared to systems that are tested for functionality at intervals. For ease of commissioning, the automated control systems offer a Human-Machine Interface (HMI) option. During commissioning or a change in program, all threshold values that must not be exceeded by the remote-controlledmonitors can be adjusted in the control cabinet without having to adjust any settings directly at the site of the remote- controlled monitors. In the case of very large systems, this offers an invaluable time gain during commissioning, service and use. It is not only thresholds and rest positions that can be programmed viaadisplay.Thebestoscillationmodefortherespectivesystemcanalso beindividuallyselectedandprogrammedforsingleormultiplemonitors. Currently, four different oscillating modes are generally used which allowadaptation to the various requirements in different applications. This feature allows the hazardous areaswithin these applications to be separated into individual zoneswhereoneor even severalmonitorswill apply their extinguishing agent in case of an alarm. The following four oscillating modes are normally used: If control systems for remote-controlled monitors are intercon- nected to fire detection systems (i.e. IR cameras), pre-selection of individual zones can be skipped. Themonitorwill then swivel to an area identified by the fire detection system and will start the extinguishing operation directly at the source of the fire. In the case of locally confined initial fires, this results in maximum firefighting suc- cess while consuming a minimum amount of extinguishing agent and affecting only a limited area. q Zimmermann is head of the engineering depart- ment since 2012. He is in charge of foam-proportioner and fire-monitor design and development.

Monitor in hangar application.

Remote foam pipe.

February 2020 • MechChem Africa ¦ 27