WASHING METHOD AND WASHING APPARATUS OF WATER QUALITY DETECTOR

PROBLEM TO BE SOLVED: To provide a washing method and a washing apparatus of a water quality detector which prevents solid matters, such as sand and crystal, from colliding with an electrode part at the time of washing, and in which the breakage of the electrode part is inhibited.SOLUTION: The washing method removes a pollution substance adhering to a washing object part of a water quality detector in contact with sample water by the action of compressed air injected from a washing nozzle 14. In the washing method in which a solenoid valve 17 is made to carry out the open operation at least one time in a one washing period, thereby which enables the supplying of the compressed air through the solenoid valve 17 to the washing nozzle 14 from an air tank 16; the filling of air to the air tank 16 is started from the starting point of the one washing period, and at a nozzle discharge time T6 which has a prescribed time width from the starting point, the air of lower pressure (for example, atmospheric pressure ) than that of the compressed air is supplied to the washing nozzle 14 from the air tank 16 through the solenoid valve 17, and a solid matter in the nozzle is made to discharge with the air and the sample water.