| 摘要 |
PURPOSE: To accurately detect a maintenance period such as the washing in a heat exchanger and to perform automatic washing by providing a contamination detection sensor consisting of a dissolved oxygen electrode and a flow cell, a three-way valve, and a container for storing acid for washing. CONSTITUTION: A calibration liquid and a buffer solution are mixed, a liquid where dissolved oxygen is saturated passes through a heat exchanger 18 in a constant-temperature bath 19 along with air and reaches a set temperature, and then the liquid is sent to a contamination detection sensor 22. The amount of dissolved oxygen consumption (DO1 ) due to germ multiplied into a piping system or the heat exchanger 18 is measured and stored at a controller 6 for each measurement. Then, the mixed solution is sent to a microbe sensor 14 and the dissolved oxygen (DO2 ) is measured. By adding DO1 and DO2 for each measurement, the output decrease content of the sensor 14 of the dissolved oxygen consumption due to germ can be compensated. Also, by outputting a signal from a device 6 where the DO1 concentration is equal to DO2 concentration, the exchange and washing timings of a pipe system can be detected. When the washing timing is detected, the channel to the flow cell 21 is switched by a three-way valve 23. |
