| 摘要 |
<p>PURPOSE:To prevent dust particles from sticking on a hot wire by arranging electrothermic nets which catch dirt particles in sucked air on the upstream side of a heat wire part arranged in an air passage and supplying a heating current for burning out the dirt particles to the electrothermic nets. CONSTITUTION:The plural electrothermic nets 6a and 6b are arranged opposite each other at the upstream side of the installation part of the hot wire 4 in the air passage of a main body 1; and the electrothermic net 6a is used as a discharging electrode and the electrothermic net 6b is used as a dust collecting electrode. When an air flow is measured, a high voltage, e.g. 1kV is applied between the electrothermic nets 6a and 6b to charge dust electrostatically and forcibly on the side of the electrothermic net 6a and collect the dust electrostatically on the side of the electrothermic electrode 6b. Then, a burning current is supplied to the electrothermic net 6b after the air flow rate is measured to burn out the dust sticking on the electrothermic net 6b. Consequently, dust particles are securely prevented from sticking on the hot wire 4 for flow rate measurement.</p> |
