| 摘要 |
PURPOSE:To improve an accuracy of water feeding to a set water level by a method wherein a pressure between a water storing part and a pressure sensor is set to a stable value, the pressure is stored as a water level reference value, the reference value is compared with a previous value at every time, and if there is a difference of more than a specified value of the previous one, the previous one is applied and if the difference is within a specified value, the value will be revised. CONSTITUTION:An operation of a water supplying part 10 is stopped, a changing-over means 12 is changed over to a return pipe 5 at a step 12, a pump 6 is operated to cause water to be circulated through an outgoing pipe 4, a water storing part 1, a returning pipe 5 and a pump 6. At this time, since air is leaked at the water storing part 1, it shows a stable value PO. If the circulating mode operation is terminated, the changing-over means 12 is connected again to the water supplying pipe 11 to change-over to a water supplying mode. If a pressure value is a difference more than a specified value as compared with the previous water level reference value, the previous one is used as the water level reference value. In turn, if the value is less than the specified value, a present value is revised as a water level reference value at a step 20 and stored. If the set value water supplying is fed to a point where a pressure PA is increased, the value becomes the set water level and since the value of PO+PA is in a stable value, it may easily be returned back to the set position even in case of replenishment with water. |
