CONTROL LOGIC_ITALY: SPARK DETECTION & EXTINGUISHING SYSTEM
Everybody knows that the fire rate in the woodworking industry (saw-mills, manufacturers of furniture, chipboards Industries & MDF, OSB, Plywood, Hardboard, etc.) is very high, resulting in expensive insurance premiums. Unfortunately, in case of fire, the insurance often does not cover all damages. To all this it should be added that insurances companies are often open to grant remarkable discounts when the woodworking plants is equipped with spark detectors.
The detector is used to dry chips in manufacturing of chipboard panels. Due to a possible malfunction, instead of only drying them. It should be mentioned that wood catches fire about 300°C, while temperature inside the drier reaches approximately 350° C. The margin of safety is therefore very low. In order to avoid that bins and working served by the exhaust plant are set on fire, the Control Logic, in Milan based firm, supplies special devices able to detect and extinguish all kind of sparks in due time, before they reach destination. The time available is very short indeed, since particles speed inside the conveyor is approx. 30 m/sec. and pipes can also very short, sometimes less than 10 m. Three are the elements challenging the spark detector: the time taken by the spark to transit in front of the observing window, the spark size and the pipe diameter. The spark detector does not work like a human eye. In fact it is not estimated by the light but by the infrared radiation, thus detecting sparks which could not be seen by the eye. Indeed many of the sparks normally detected by the device would be invisible-for a human observer. Burning particles emit red light and infra-red thermic radiation, the latter in a quality 100 times larger. In addition the spark detector is sensitive only to moving burning bodies. This feature makes the device suitable for installation also in well-lighted open spaces, to survey belt and helical conveyors. To grant an easy check of its efficiency, the detector is equipped with a “test” device. A remote control button permits to simulate the passage of a spark in order to check the efficiency of either the water jet or the lock-gate. The more sophisticated systems are equipped with an automatic control of all main functions, operating an alarm signal if a spark has not been extinguished or stopped, if a detector is out of order or if there is a leakage in the water jet system.