Spark detectors
The highly advanced Minimax infrared detectors are engineered for the immediate identification of sparks in industrial environments. The detector is flush mounted with the inside wall of the duct and responds to the infrared radiation generated by passing sources of heat, i.e., sparks or glowing embers. The detector continuously checks the correct function of its electronics. An additional spark test detector system is available to monitor visibility. Any faults identified are automatically relayed to the control panel notifying plant personnel. In areas where high ambient temperatures are expected, flexible temperature resistant fibre optic cables are used to thermally separate the electronic components of the spark detector from these hot areas. For conveyor systems which are not completely enclosed, e.g., conveyor belts, special spark detectors insensitive to daylight can be installed.
Automatic extinguishing unit
Upon receipt of a signal from the spark detector, the control panel activates the quick acting solenoid valve of the automatic extinguishing unit releasing a minimized quantity of extinguishing water. The water is injected by means of the unique fl at spray nozzles engineered for the conditions in conveying systems. It creates a water spray which covers the entire cross section of the duct. Conventional nozzles, though, can only fill the cross section completely with the help of turbulences in the duct. This requires a certain length of duct. In the installation this means longer necessary distances between the position of nozzles and downstream equipment to be protected. Distances, which are not available very often. In ducts without power venting only gravity is the driving force and, consequently, no turbulences occur. In such chutes, the spray pattern of conventional nozzles will completely fill the section of the duct only if more than one nozzle is installed, whereas with the Minimax flat spray pattern nozzle one nozzle will be sufficient in most cases. In Minimax systems, the flow detector is not installed at the water supply, but rather at the automatic extinguishing unit. This allows plant personnel to identify problem zones easily. The stainless steel material and the flush construction of the Minimax flat spray nozzle increase its durability against plugging and abrasion even in the most severe environments. The ball valve as part of the valve unit can also be monitored electronically to ensure that it is always in the correct operating position.
Water supply
The Minimax pressure booster system, consisting of a centrifugal pump and a diaphragm pressure vessel, is the most cost effective and efficient means of increasing the water supply pressure if the minimum pressure required cannot be provided by an existing sprinkler system or a service water supply. The diaphragm pressure vessel supplies water with sufficient pressure immediately upon activation of the automatic extinguishing unit. The centrifugal pump automatically supplies the pressure vessel if the water pressure drops below a specified value. Even in the unlikely event of pump failure, several extinguishing impulses from the diaphragm pressure vessel are possible. Optionally, a monitoring device is available to detect a broken membrane inside the diaphragm pressure vessel.
