Thermal flowmeter with fluid distriminant function

Abstract

A thermal flowmeter with fluid discriminant function, comprising a heater, a flow rate detecting thermosensitive body, and a flow rate detecting electroconductive fin plate (44) extending into a fluid flow channel (3), these three parts being disposed for mutual heat transfer, a flow rate detecting unit (4) so designed that the electric characteristic values of the flow rate detecting thermosensitive body vary in response to the flow of the fluid in the fluid flow channel (3), the fluid temperature detecting thermosensitive body and the fluid temperature detecting electroconductive fin plate (44') extending into the fluid flow channel (3) being disposed for mutual heat transfer, and a fluid temperature detecting unit (6) so designed that the electric characteristic values of the fluid temperature detecting thermosensitive body vary in response to the fluid temperature. Fluid flow rate detection is effected on the basis of the electric characteristic values of the flow rate detecting and fluid temperature detecting thermosensitive bodies, and fluid discrimination is effected by measuring the conductivity between the flow rate detecting and fluid temperature detecting fin plates (44, 44'). According to this thermal flowmeter, discrimination of whether the fluid is the required one or not is made by a simple mechanism and passage of erroneous fluid can be avoided.

Description

technical field [0001] The invention belongs to fluid flow detection technology, and relates to a thermal flowmeter with fluid discrimination function. Background technique [0002] In the past, as a flowmeter [flow sensor] (or flow meter [flow velocity sensor]) for measuring various fluids, especially liquid flow (or flow velocity), various types of detection devices were used for the reason of low price What is used is a flow meter of a so-called thermal type (in particular, a side heating type). [0003] As the side-type flowmeter, thin-film technology is used on the substrate, and the thin-film heating element and the thin-film temperature-sensing element are stacked through an insulating layer to form a sensor sheet, and the sensor sheet is arranged and used in a manner that can conduct heat with the fluid in the pipeline. . The electrical characteristics of the temperature-sensitive body, such as the resistance value, are changed by heating the temperature-sensitive ...

AI Technical Summary

Problems solved by technology

[0009] Although using a small part of the supply source as described above has great advantages in practice, on the other hand, when the fluid supply source is replaced, it is likely to be connected to a fluid supply source other than the required fluid.

In this case, if the fluid supply is performed without realizing this, not only the thermal properties of the required fluid and the actually supplied fluid are different, and the correct flow rate measurement cannot be made, but also due to the wrong supply of fluid, it will become a problem. Causes of adverse events in manufacturing and analysis or causes of medical errors

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