| 摘要 |
<p>PURPOSE:To obtain a durable thin film resistor type flowmeter, by forming a glass layer on a supporting body of an insulating material, and forming a heat sensitive resistor layer thereon. CONSTITUTION:A heating resistor element 1 and resistors 11-13 constitute a bridge. The differential voltage is amplified by an amplifier 14. A feedback circuit drives a transistor 15. The heating resistor body 1 is arranged in the flow path of fluid together with a resistor for temperature compensation. Control is performed through the feedback circuit so that a specified temperature difference is always maintained with respect to an ambient temperature. Leads 42 such as platinum are fixed to both ends of a bobbin 40 of the heating resistor 1 with a heat resisting bonding agent 44. A glass layer 52 is formed on the surface of the bobbin 40. A heat sensitive resistor film (platinum layer) 54 is formed thereon, and a glass layer 56 is further formed thereon. Since the heat sensitive resistor film 54 is formed on the glass layer 52, the effect of strain due to thermal expansion and contraction is prevented, and durability is improved.</p> |
