| 摘要 |
<p>PURPOSE:To positively detect the formation of dew in a cylinder by providing a humidity sensor to a spherical regenerator fixed to an insulating plate. CONSTITUTION:A humidity sensor 1 which changes its resistance value by the humidity of the surface thereof is fixed to a flat part on the surface of a spherical regenerator 2. The regenerator 2 is fixed to an insulating plate 3 at the other flat part. The regenerator 2 is formed of, for example, aluminum allay, and the insulating plate 3 is made of material with a small thermal conductivity, e.g. synthetic resin. The regenerator made of metal or the like, and having a large thermal capacity is formed to have a small surface area into a sphere, and therefore the regenerator transfers less heat to the neighborhood. Moreover, since the regenerator is held by the insulating plate 3, the thermal conduction to a main body of the VTR is kept small. The cylinder is maintained approximately at the same temperature as the regenerator. Accordingly, the humidity sensor fixed to the regenerator forms drops of dew approximately at the same time with the cylinder, so that the formation of the dew can be quickly detected.</p> |
