| 摘要 |
<p>PURPOSE:To accurately detect the air in the vapor piping by passing a near infrared ray which contains an absorption spectrum band due to vapor through the atmosphere in the vapor piping. CONSTITUTION:When the output light of a light emitting diode 25 passes through a gap 22 for a sample, a component with specific wavelength in a range of almost 1.35-1.40mum is absorbed by vapor and the adsorption amount varies greatly with the amount of the vapor. Consequently, light incident on a phototransistor 26 varies with the amount of the vapor and the current of the phototransistor 26 varies, so the level of the current is detected by a detecting circuit 32 to know the amount of the vapor in the vapor piping 1 and also know whether or not there is air and its amount from the amount of vapor. Consequently, the air in the vapor piping is accurately detected.</p> |
