| 摘要 |
PURPOSE:To detect a freezing state accurately by coating the surface of a conductive rod by an insulating film having high permittivity, contacting an electrode rod whose synthesized thermal conductivity is close to that of ice with the surface of a freezing pipe, thereby obtaining the electric capacity between the cooling water and the conductive rod. CONSTITUTION:The electrode rod 2 is formed by coating the surface of the conductive rod 3 having a specified length by the insulating filn having the high permittivity. The apparent thermal conductivity of the electrode rod 2 is made as close as possible to the thermal conductivity of ice, so that the freezing state in the surrounding area around the electrode rod 2 is equal to the freezing state of the whole area. One end of said electrode rod 2 is contacted with the cooling pipe 1 at a right angle or obliquely. A lead wire 5 is connected to an AC power source 9 through an ammeter 8 from the other end of the electrode rod 2. When a voltage is applied to the inside of the cooling water 10 from the other end of the AC power source 9, a current flows through an electric capacity formed by the cooling water 10 and the conductive rod 3, and its amount varies in response to the freezing state. In this way, the freezing state can be accurately detected. It is suitable for remote control of an ice bank. When the electrode rod is inclined, the sensitivity is increased. |
