JP2000019030A - Heat flux meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a heat flux meter which is constituted to measure a heat flux from the differential formula of a thermocouple formed of core wires by passing a sheath tube having the core wires through an inner tube inserted into a heat receiving plate attached to the front face of a side plate forming a maintenance space from the rear side of the side plate in such a way that the tube is opened in the maintenance space to accurately measure the heat flux even when the insulation resistance of the maintenance space changes. SOLUTION: An inner tube 090 is attached to a side plate 011 to the front face of which a heat receiving plate 010 is attached so as to form a maintenance space 030 of the plates 011 and 010 in such a way that the front end of the tube 009 is opened in the space 030. A sheath tube 012 is put in the inner tube 009 and three core wires 012a, 012a, and 014 are passed through the sheath tube 012. The core wires 012a form a thermocouple in such a way that one of the wires 012a is passed through the heat receiving plate 010 and welded 013a to the front face of the plate 010 and the other is passed through the side plate 011 and welded to the rear face of the side 011. The remaining core wire 014 is laid in an insulating material 015 in the sheath tube 012 and used for the measurement of the insulation resistance between the core wire 014 and the other core wires 012a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat flow meter suitable for use in a commercial or industrial boiler, heating furnace, or the like.

[0002]

2. Description of the Related Art An example of a conventional heat flow meter will be described with reference to FIGS. First, in FIG. 3 showing the configuration of the heat flux meter 001, reference numeral 011 denotes a side plate, in which a maintenance space 030 is formed, and a heat receiving plate 010 is mounted on the front surface thereof. The heat receiving plate 010 has a disk shape, and its circumferential portion is welded to the side plate 011 by welding 013b. The heat receiving plate 010 and the side plate 011 are referred to as elements, and constitute a portion that receives a heat flux and generates a heat flow.

An inner tube 009 is fitted behind the side plate 011 so as to open into the maintenance space 030 at the center, and an outer tube 007 is fitted into the outer peripheral portion. Between the pipe 007 and the side plate 011,
They are welded 013e and 013c, respectively. A middle tube 008 is provided between the outer tube 007 and the inner tube 009, and a cooling water 004 flows through an annular space between the middle tube 008, the outer tube 007, and the inner tube 009.

In the inner tube 009, a sheath tube 012 of a two-core wire (almer-almer) 012a is provided.
The core wire 012a made of alumel wire introduced into the maintenance space 030 is respectively located at the center of the front surface of the heat receiving plate 010,
A small hole is formed in the side plate 011 near the inner pipe 009, and a core wire is welded through the small hole 013a and 013d, respectively.

The material of the heat receiving plate 010 and the side plate 011 uses a commonly used thermocouple material. In the conventional example, chromel having a smaller thermal conductivity (larger thermal resistance and a temperature difference can be obtained) ) Is used for the heat receiving plate 010, and alumel having a higher thermal conductivity is used for the side plate 011 (to increase the cooling effect and increase the temperature difference from the center of the heat receiving surface).

[0006] The maintenance space 030 has a core wire 012a.
The welding 013a, 013b and the heat receiving surface 010 of the
1 is indispensable for welding 013b.
The rear of the side plate 011 is cooled by the cooling water 004 as described above, and the heat received by the front heat receiving plate 010 flows from the front to the rear (from left to right in FIG. 3), and the temperature difference from the front to the rear. Will occur.

FIG. 4 shows the principle of the heat flow meter of FIG. 3 having the above configuration. To explain this, the heat receiving plate 0
10 (Chromel material) front heat receiving surface and Alumel core wire 0
An electromotive force of the temperature contact 016 is generated by welding 013a to the side 12a, and a temperature contact is formed between the side plate 011 and the welding 013b of the side plate 011 around the heat receiving surface of the heat receiving plate 010 by the welding 013d of the side plate 011 (aluminum material) and the core wire 012a. 017
Electromotive force is generated.

As shown in the figure, if the voltage 018 is measured between the core wires 012 of Alumel, the differential type of the thermocouple is established and the heat receiving plate 0
It is possible to know the difference between the central temperature of the heat receiving surface of No. 10 and the temperature around the heat receiving surface of the heat receiving plate, that is, the electromotive force of the temperature difference. Even if the above-mentioned electromotive force is measured, the heat flux 050 of the boiler or the like cannot be directly obtained.
Three tests are required.

FIG. 5 is a schematic diagram of a case where the test is performed. For the verification, a black body furnace 019 is generally used. The black body furnace 019 includes a refractory material 021 and a heater 020, and a small cavity is provided therein. Heat flow meter 00 in the cavity
By inserting 1, the relationship between the calorific value 023 and the electromotive force 022 can be obtained. The amount of heat is determined by measuring the amount of radiation according to the following equation 1.

[0010]

(Equation 1)

As described above, by obtaining the temperature of the furnace wall of the black body furnace 019 and the electromotive force 022 of the heat flux meter 001, a verification curve 024 as shown in FIG. 6 can be obtained. As shown in FIG. 6, the calibration curve 024 has a calorie of 023.
Is plotted on the vertical axis and the electromotive force 022 is plotted on the horizontal axis. From this calibration curve, the actual heat flux 050 in a heating furnace, a boiler, or the like can be obtained.

[0012]

The conventional heat flux meter described above has the following problems in structural and manufacturing aspects. First, welding 0 between the heat receiving surface of the heat receiving plate 010 and the side plate 011 is performed.
Reference numeral 13b denotes a bond between dissimilar metals, which causes poor welding due to a difference in coefficient of thermal expansion, air enters and exits the maintenance space 030, and moisture in the air causes insulation failure between the core wires 012a.

Further, since the dissimilar metal is also welded between the inner pipe 009 and the side plate 011, it is incompletely connected and the cooling water 004 is formed.
Leakage (although it is extremely small), and as a result, insulation failure occurs between the core wires 012a. Furthermore, due to the structure, the core wire 012a is welded to the heat receiving plate 010 and the side plate 011 so that the insulation resistance cannot be measured (normal verification cannot be performed). For this reason, erroneous measurement was caused.

According to the present invention, there is provided a heat receiving plate attached to a front surface of a side plate having a maintenance space formed therein, an inner tube fitted into the maintenance space from behind the side plate, and a sheath having a core wire in the inner tube. A heat flux meter that measures the heat flux from the differential type of thermocouple formed by the core wire through the tube and measures the insulation resistance in the maintenance space to enable accurate measurement of the heat flux The goal is to provide a total meter.

[0015]

According to the present invention, in order to solve the above-mentioned problems, a three-core sheath tube is inserted into an inner tube inserted into the maintenance space from the rear side of the side plate, and a third one of the core wires is inserted. The first core wire is joined to the front surface of the heat receiving plate, the second core wire is joined to the back surface of the side plate, and the third core wire is installed in an insulating material in the sheath tube immediately before the maintenance space, Provided is a heat flux meter configured to measure a heat flux from a differential type thermocouple formed by a second core wire and measure an insulation resistance between the third core wire and another core wire.

According to the heat flux meter of the present invention, as described above, the simple configuration of providing the non-grounded third core wire is used exclusively for measuring the insulation resistance, and the insulation resistance between the other core wires is reduced. It becomes measurable. As a result, even a slight insulation failure between the core wires that affects the measurement result as the heat flux meter can be measured, and the measurement accuracy as the heat flux meter can be improved.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a heat flux meter according to the present invention will be described.
A specific description will be given based on the embodiment shown in FIGS. In the following embodiments, portions having the same structure as those of the conventional heat flux meter shown in FIG. 3 are denoted by the same reference numerals, and redundant description thereof will be omitted.

As shown in FIGS. 1 and 2, a three-core sheath tube is passed through the inner tube 009. Two core wires 012a among the three core wires are, as shown in FIG. 3, a central portion on the front surface of the heat receiving plate 010 and a side plate 01 near the inner tube 009.
1 are welded at 013a and 013d, respectively. These core wires 012a are guided to an external measuring instrument by a sheath tube 003.

The remaining third core wire 014 of the three core wires
Is guided in the sheath tube 012 to just before the maintenance space 030, and the tip is installed in the insulating material 015 just before the maintenance space 030. The core wire 014 is guided to an external measuring instrument by a sheath tube 002. Other configurations are shown in FIG.
Is substantially the same as the conventional heat flux meter shown in FIG. 005 and 006 are an inflow pipe and an outflow pipe of the cooling water 004 flowing between the inner pipe 009, the middle pipe 008, and the outer pipe 007.

The heat flux meter shown in FIGS. 1 and 2 has the above configuration, and the third core wire 014 installed in the insulating material 015 in the sheath tube 012 has the remaining two wires. Used to measure the insulation resistance between the core wire 012a.

The insulation resistance measured by the third core wire 014 is used to calibrate the heat flux meter value measured by the differential type thermocouple formed by the two core wires 012a. In this way, accurate measurement of the heat flux is possible even if the insulation resistance in the maintenance space changes.

[0022]

As described above, in the heat flux meter according to the present invention, a three-core sheath tube is inserted into an inner tube inserted into the maintenance space from the rear of the side plate, and the three core wires are inserted into the inner tube. A first core wire is joined to a front surface of the heat receiving plate, a second core wire is joined to a back surface of the side plate, and a third core wire is installed in an insulating material in the sheath tube immediately before a maintenance space, The heat flux is measured from a differential type thermocouple formed by the first and second core wires, and the insulation resistance is measured between the third core wire and another core wire.

Therefore, according to the heat flux meter of the present invention, the first and the second core wires are measured by using the insulation resistance between the other core wire measured by the third core wire installed in the insulation material in the sheath tube without grounding. By calibrating the value of the heat flux measured by the second core wire, it is possible to measure the accurate heat flux regardless of the change in the insulation resistance. As described above, according to the present invention, the problem can be achieved with a simple configuration in which only one core wire is added in the sheath tube.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a structure of a heat flux meter according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a portion A in FIG. 1;

FIG. 3 is a longitudinal sectional view showing the structure of a conventional heat flux meter.

FIG. 4 is an explanatory diagram for explaining the principle of the heat flux meter shown in FIG. 4;

FIG. 5 is an explanatory diagram showing an outline of a facility for testing a relationship between an electromotive force and a calorific value in a heat flux meter.

FIG. 6 is a diagram showing an example of a test curve showing a relationship between an electromotive force and a calorific value in a heat flux meter.

[Explanation of symbols]

 001 Heat flux meter 002 Sheath tube 003 Sheath tube 004 Cooling water 005 Inflow tube 006 Outflow tube 007 Outer tube 008 Middle tube 009 Inner tube 010 Heat receiving plate 011 Side plate 012 Sheath tube 012a Core wire 013a Welding 013b Welding 013c Welding 013d Welding 013d Welding 015 Insulation material 016 Temperature contact 017 Temperature contact 018 Voltage 019 Black body furnace 020 Heater 021 Refractory material 022 Electromotive force 023 Heat quantity 030 Maintenance space 050 Heat flux

Claims (1)

[Claims] 1. A heat receiving plate attached to a front surface of a side plate having a maintenance space formed therein, an inner tube fitted into the maintenance space from behind the side plate, and a three-core sheath tube in the inner tube. The first core wire of the three core wires is joined to the front surface of the heat receiving plate, the second core wire is joined to the back surface of the side plate, and the third core wire is an insulating material immediately before the maintenance space in the sheath tube. So that the heat flux is measured from a differential type thermocouple formed by the first and second core wires, and the insulation resistance is measured between the third core wire and the other core wire. A heat flux meter characterized by comprising.