DETECTION OF NOZZLE CLOGGING

PURPOSE:To discover nozzle clogging in an early period without requiring considerable personnel expenses with such a nozzle which injects a liquid refrigerant to be cyclically used by detecting the resistance between a pair of electrodes provided in the injection range of the liquid. CONSTITUTION:For example, cooling water is forced to the two-fluid nozzles 2 by a pump 5 and air is forced thereto by a blower 6. The cooling water is made into fine water drops 6 by air jets and is injected from the nozzles 2 so as to be sprayed together with the air onto a hot steel sheet 3. The cooling water used to cool the hot steel sheet 3is recovered in a tank 4 and is supplied again to the nozzles 2 after cooling. A pair of the electrodes 11, 11' to be impressed with a voltage by a power source 12 are provided in water drop group 8. The resistance value to be determined by the cooling water exists between a pair of the electrodes if the nozzle 2 is normal and the cooling water exists between the electrodes 11 and 11'. The certain specified voltage is then measured by a meter 15. The voltage different from the above-mentioned voltage is measured by the meter 15 if the cooling water does not exist between the electrodes 11 and 11' as a result of the nozzle clogging. The clogging of the nozzle 2 is, therefore, discovered.