JPS61239127A - Heat flux sensor - Google Patents

Abstract

PURPOSE:To manufacture easily the titled sensor, and also to measure exactly a heat flux by forming a heat flux receiving plate by a non-conductive substance. CONSTITUTION:A heat flux receiving plate 11 of an element 2a is formed by a non-conductive substance, for instance, a thin plate of alumina ceramics. Also, a thermopile 5 is formed on the surface positioned at a heat sink 1 side of the heat flux receiving plate 11, and the heat flux receiving plate 11 is fixed to the heat sink 1 by an adhesive agent layer (b). Moreover, the heat flux receiving plate 11 itself serves as a member for insulating the thermopile 5, as well, therefore, no error factor exists consequently, and by only managing a thickness of the heat flux receiving plate 11, a measurement can be executed exactly. Also, a process for forming an insulating layer with a high accuracy is not required, therefore, the titled sensor can be manufactured easily.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a heat flux sensor used for measuring heat flux received from the outside, and particularly aims to facilitate manufacturing and realize accurate measurement. The present invention relates to a heat flux sensor that can be used to measure heat flux.

[Technical background of the invention and its problems]

In various fields, it is often necessary to accurately measure heat flux received from the outside.

Conventionally, a heat flux sensor configured as shown in FIG. 1 has been considered as a heat flux sensor used for measuring such heat flux. That is, this sensor is broadly divided into a heat sink 1 having a recess A in the center, and an element 2 fixed to the heat sink 1 so as to cover the opening of the opening 8BA. Element 2 includes a heat flux receiver formed of a thin metal plate, a plate 3, an insulating layer 4 formed on the surface of the plate 3 located on the heat sink 1 side, and a heat sink 1 of the insulating layer 4. The recess A is located on the side.
A thermopile 5 is arranged in close contact with the above surface in a meandering manner within a range facing the above surface, and this thermopile 5 is fixed to the surface of the insulating layer 4, and both sides of the element 2 are attached to the so-called banks of the heat sink 1. an adhesive layer 6 for fixing;
The heat flux receiver is composed of a high-emissivity coating layer 7 provided on the surface of the plate 3 opposite to the heat sink 11111 and located above the opening of the recess A. The thermopile 5 is provided such that one thermal contact 8 is located near the heat sink 1 and the other thermal contact 9 is located away from the heat sink 1, that is, approximately on the center line of the recess A. .

This heat flux sensor measures heat flux based on the following principle. In other words, if the heat flux absorbed by the plate 3 of the heat flux receiver is Q (W/Td,), then the heat flux receiver of the plate 3 is T-Ta-Q ・(L" = xz)/2λu, -=
--------(1) A temperature distribution occurs. however,(
In equation 1), X is the coordinate taken from the center of the heat flux receiving plate 3 toward one side fixed to the heat sink 1, and the heat flux receiving is the half length of the plate 3 [m, ], λ The heat flux receiver is the thermal conductivity of the plate 3, μ is the heat flux receiver is the thickness of the plate 3 [, m,
], the heat flux receiver at the position of tiM× is the temperature of plate 3,
Ta is the temperature of the heat sink 1.

Now, let us assume that the coordinates of the thermal junction 8 located on the heat sink 1 side of the thermopile 5 are ±1, and the temperature difference between them is △T (K)
Then, according to equation (1), △T=Q・12/2λμ・
・・・・・・・・・・・・・・・(2) Therefore, if ΔT is measured, Q can be measured. In other words, Q=2・λ・μ・△T/12・・・・・・・・・・・・
It can be measured as (3). Here, thermopile 5 is
It is provided to accurately measure ΔK, which is an extremely small value.

However, the conventional heat flux sensor configured as described above has the following problems. That is,
The plate 3 of the heat flux receiver is made of a thin metal plate. Metal plates generally have high thermal conductivity, so (2)
As is clear from the equation, it is necessary to reduce the thickness μ in order to increase ΔD. For this reason, the thickness μ of the plate 3 of the heat flux receiver is usually set to a value equal to or less than the thickness of the insulating layer 4. However, in such a configuration, the thermal conductance of the heat flux receiver in the longitudinal direction of the plate 3 is determined by the thickness of the insulation layer 4 and the degree of bonding between the insulating layer 4 and the heat flux receiver plate 3. It is easy to be influenced by this, and as a result, there is a problem in that only measurement results with large errors can be reported. Furthermore, when the thermal conductivity of the insulating layer 4 is small, the thermal resistance in the thickness direction will vary due to variations in the thickness of the insulating layer 4 and variations in the degree of bonding between the heat flux receiver and the plate 3. As a result, the obtained temperature difference Δc also had a large error, and after all, it was essentially difficult to expect accurate measurement.

[Purpose of the invention]

The present invention has been made in view of these circumstances, and its purpose is to provide a configuration that can eliminate error factors.
It is an object of the present invention to provide a heat flux sensor that can contribute to the realization of accurate heat flux measurement and that can be manufactured easily.

[Summary of the invention]

A heat flux sensor according to the present invention includes a heat sink, a heat flux receiver partially fixed to the heat sink, a plate, one thermal contact of the heat flux receiver in contact with the plate at a position close to the heat sink, and a heat flux receiver that is partially fixed to the heat sink. The heat flux receiver includes a thermopile fixed to a plate with the other thermal contact in contact with the thermopile at a position remote from the thermopile,
The heat flux receiver is characterized in that the plate is made of a non-conductive material.

〔Effect of the invention〕

As mentioned above, the heat flux receiver has plates made of a non-conductive material. In other words, by forming the plate of the heat flux receiver with a non-conductive material, the heat flux receiver eliminates the insulating layer between the plate and the thermopile, which was a cause of measurement errors in conventional sensors. . Therefore, the causes of temperature differences and measurement errors can be eliminated, and the heat flux receiver can perform accurate measurements simply by controlling the thickness of the plate. Also, unlike conventional sensors, metal heat flux receivers can omit the process of forming an insulating layer on one side of the plate while controlling the bonding distribution and thickness distribution uniformly. It is also possible to facilitate the

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a heat flux sensor according to an embodiment of the present invention, and the same parts as in FIG. 1 are designated by the same symbols. Therefore, the explanation of the overlapping parts will be omitted.

In this embodiment, the heat flux receiver of the element 2a is formed by a plate 11 of a non-conductive material, for example a thin plate of alumina ceramic. In this heat flux receiver, a thermopile 5 is formed on the surface of the plate 11 located on the heat sink 1 side, and the heat flux receiver plate 11 is fixed to the heat sink 1 by an adhesive layer 6. Note that 12 in the figure indicates an extremely thin protective layer coated on the thermopile 5 to prevent scratches and oxidation.

With this configuration, the plate 11 of the heat flux receiver also serves as a member that insulates the thermopile 5, so unlike conventional sensors, there is no error factor, and the heat flux receiver is the thickness of plate 11]! l! Accurate measurements can be made simply by Also, unlike conventional sensors, it does not require a process to form an insulating layer with high precision.
Manufacturing can also be facilitated, and the above-mentioned effects can be obtained after all.

Note that the present invention is not limited to the embodiments described above. The increase in the time constant may be suppressed by forming the plate of the heat flux receiver from a crystal that is non-conductive and has good thermal conductivity, such as sapphire.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of a conventional heat flux sensor, and FIG. 2 is a partially cutaway perspective view of a heat flux sensor according to an embodiment of the present invention. 1... Heat sink, 5... Thermopile, 11.
...The heat flux receiver is a plate. Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (3)

[Claims] (1) A heat sink, a heat flux receiving plate partially fixed to the heat sink, one thermal contact of the heat flux receiving plate is brought into contact with a position close to the heat sink, and the other thermal contact is placed in contact with a position away from the heat sink. A heat flux sensor comprising a thermopile fixed to the heat flux receiving plate with contacts in contact with each other, wherein the heat flux receiving plate is made of a non-conductive material. (2) The heat flux sensor according to claim 1, wherein the non-conductive substance is ceramic. (3) The heat flux sensor according to claim 1, wherein the non-conductive substance is a sapphire crystal.