| 摘要 |
An ice thickness indicator is disposed at the surface of a body of water, as by floats, and provides a means to indicate whether the water has frozen to a predetermined thickness. The device includes an enclosed chamber which may be filled with water. The chamber is expansible by means of a movable member which partly defines the chamber. The movable member is located below the surface of the water and is connected to an upwardly extending indicator which displays different indications, depending on the relative position of the movable member. As the body of water in which the device is immersed freezes, the water within the expansible chamber also freezes and expands to cause movement of the movable member and operate the indicator means.
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