| 摘要 |
<p>PURPOSE:To achieve an accurate flow rate inspection regardless of a sharp change in flow rate by wrapping a sensor coil for a sensor of a heat measuring type mass flowmeter with a heat insulating material comprising a ceramic fiber such as ceramic paper to get rid of effect by a disturbance. CONSTITUTION:A tubule 1 made of metal such as stainless steel, for example, with an inner diameter of about 0.5mmphi as bent roughly in a shape of U runs through a substrate 2 at both ends 1a and 1b. Then, an upstream side sensor coil A and a downstream side sensor coil B wound in a coil are provided tightly on the outer circumference of the tubule 1. In these coils A and B, a current flowing is fed to the tubule 1 as controlled constantly, an unbalance voltage is generated in a bridge circuit with a change in a resistance value proportional to a temperature change of the coils A and B and the voltage is detected to measure a mass flow rate of a fluid flowing through the tubule 1. Grooves 5 are formed on respective halves of half-split metal cases 4' and 4 and a heat insulating material 6 comprising a ceramic paper having a ceramic fiber formed in a paper within the grooves 5 is wrapped tightly on the outer circumferences of the coils A and B.</p> |
