Flowmeter for measuring a flow rate using a heat exchange principle
Provided is a flowmeter with a flow tube through which fluid flows; a cooling apparatus adapted to cool a part of the flow tube; a first temperature detecting section for detecting the temperature of the flow tube cooled by the cooling apparatus; a second temperature detecting section for detecting the temperature of the cooling apparatus; a third temperature detecting section for detecting the temperature of a non-cooling area upstream of a cooling area in the flow tube; and an information processing section, which controls the cooling apparatus make a difference between the temperature detected by the second temperature detecting section and the temperature detected by the third temperature detecting section to be a prescribed value, and calculates the flow rate of the fluid flowing in the flow tube.
1. A flowmeter comprising:
a flow tube through which fluid flows;
a cooling apparatus adapted to cool a part of the flow tube;
a first temperature detecting section adapted to detect a temperature of a cooling region of the flow tube, the cooling region being cooled by the cooling apparatus;
a second temperature detecting section adapted to detect a temperature of the cooling apparatus;
a third temperature detecting section adapted to detect a temperature of a non-cooling region upstream of the cooling region in the flow tube; and
an information processing section adapted to control the cooling apparatus so as to make a difference between a detected temperature by the second temperature detecting section and a detected temperature by the third temperature detecting section equal to a predetermined value, and calculate a flow rate of the fluid flowing through the flow tube on a basis of a difference between the detected temperature by the second temperature detecting section and a detected temperature by the first temperature detecting section, wherein
the second temperature detecting section being arranged on the cooling apparatus so as to measure a temperature of a portion of the cooling apparatus in which a temperature is first influenced by the fluid because of the flow of the fluid through the flow tube, wherein the portion of the cooling apparatus is on an upstream side in the cooling region of the flow tube.
2. The flowmeter according to claim 1 , wherein
the cooling apparatus comprises: a Peltier element having an endothermic surface on one side and an exothermic surface on the other side; and a highly thermal conductive plate member provided on the endothermic surface, the highly thermal conductive plate member having a cover part covering the part of the flow tube.
3. The flowmeter according to claim 2 , wherein
the second temperature detecting section is further arranged in a vicinity of an area where, by the flow of the fluid through the flow tube, temperature is first influenced in the plate member by the fluid.
4. The flowmeter according to claim 1 , wherein
the information processing section changes the difference between the detected temperature by the second temperature detecting section and the detected temperature by the third temperature detecting section according to the flow rate.