JPS60250260A - Current passage construction of thermoelectric type anemometer - Google Patents

Abstract

PURPOSE:To widen the allowable deflection angle of current by making a current passage circle in the section thereof while an introduction port at the inlet side thereof in such a manner as to be larger in the diameter closer to the inlet. CONSTITUTION:An electrically heating wire 5 is applied and a high-temperature contact 10 adapted to be cooled according to the velocity of current to equal the same temperature as the heating wire and a low-temperature contact 12 to become the same temperature as the current are arranged to form thermocouples 6, 7, 9 and 11. A hood 13 is provided to cover the high-temperature contact 10 and the low-temperature contact 12 of the thermocouples 6, 7, 9 and 11 and the heating wire 5 and a current passage 14 is formed running through in the direction of crossing the heating wire 5. Then, a tranpet- or bellmouth-shaped introduction section 16 is formed at the inlet 15 side of the current path 14 in such a manner as to become larger in the diameter closer to the inlet 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of an airflow passage inserted in a direction transverse to an electrically heated heating wire in a thermoelectric anemometer that measures local velocity in an airflow.

Conventionally, this type of thermoelectric anemometer was published in Japanese Patent Application Laid-Open No. 5-77!
As shown in Publication No. 5g, a heating wire that is electrically heated is stretched vertically on the second part of the base, and the temperature is the same as that of the heating wire that is cooled according to the speed of the airflow. A thermocouple is installed with a contact and a low-temperature contact for correcting the air temperature, which has the same temperature as the airflow, placed on the bottom of the base, and a gate-shaped hood is attached to the base to cover the high-temperature and low-temperature contacts of the thermocouple and the heating wire. Te,'yl
(It forms an air flow passage with a rectangular cross section that extends in the front-rear direction across the hot wire.In this conventional product, even when the direction of the air flow is deviated from the direction of the air flow passage in the vertical or horizontal direction, The permissible deflection angle of the airflow that allows accurate measurement of wind speed but with small measurement error is 35 in the vertical direction.
The angle is 0 degrees, and in the lateral direction it is about 25 to 30 degrees, which is not wide enough for a one year old.

An object of the present invention is to improve the conventional products having the above-mentioned drawbacks, and to provide an airflow passage structure for a thermoelectric anemometer with a wide allowable deflection angle of airflow.

Next, one embodiment of the present invention will be described.

First embodiment (see Figure 1 to Figure 1) This example is a thermoelectric anemometer with an air flow passage structure.

As shown in Fig. 1, a phosphor bronze straight pillar (3) and an inverted pillar (4) are located at the center and leeward end of the tip surface (2) of the insulating square bar-shaped base (1). A heating wire (5) of nichrome wire is installed between the tip of the inverted-shaped column (4) protruding to the windward side and the tip of the straight column-shaped column (3) located directly below this column.
), and the electrically heated heating wire (5) is stretched in a direction perpendicular to the tip (2) of the base, and the tip of the base (
2) both pillars (3), (4) Alumel's first pillar (6) and second pillar (7) are threaded at the intermediate position and the windward end.
The other end of the 6f pair wire (9) of Alumel with one end (8) connected to the center of the heating wire (5) is connected to the first support (
6), and the other end of the second thermocouple wire 01 of Chromel connected 1OF at a position close to the heating wire (8) of the first thermocouple wire (9). is connected to the tip of the second support (7).

Therefore, the first thermocouple wire (9) of Alumel, the first column (6
).

The second column (7) and the second chromel thermocouple wire (01) constitute a thermocouple, and the first column is the same as the center of the heating wire (5), which is cooled according to the speed of the airflow. Second thermocouple wire (
9), 01) connection point (1(car heat power (6),
(7) , (+')> , Ql) is used as a high temperature contact for wind speed measurement, and the connection point between the second thermocouple wire 01), which has the same temperature as the air flow, and the second pillar (7) (one thermocouple ( 6) , (7
).

(Q), Ql) It? It is used as a low temperature contact for lu correction. In addition, a power source for heating the heating wire (5) is connected between the ends of the two struts (3) and (41) for the heating wire, and both struts (6) for the thermocouple.

There are thermocouples (6), (7), (
9) A wind speed indicator for measuring the thermoelectromotive force of (11) is connected.

84 at the tip of the base (1), Figures 1 and ! 1m, each strut (31, (
41, (6), (7), the heating wire (5), and each P couple wire (g), (11). The air flow passage (1) with a circular cross section is formed through the air flow passage (1 →), and a morning glory-shaped or bell mouth-shaped introduction part 0 is formed which becomes larger in diameter as it approaches the air flow passage (1 → inlet side, inlet 05). .

The dimensions of each part are as follows: The length of the air flow passage 04) is /15 mm, its diameter is 6 rtrm, the length of the introduction part Oe is 55 m1, and the diameter of the inlet 09 is /! ; with IIIT, the height of the inverted-shaped support (4) for the heating wire is 3 MM,
The depth of the heating wire (5) is 97 MIM from the entrance.

Experiment on the permissible deflection angle of airflow The thermoelectric anemometer of this example and the conventional thermoelectric anemometer with the rectangular cross-section airflow passage material described above were used, respectively. / Om /
The direction of the airflow maintained at a constant speed at the sea level is
3) , (41, (61, (7)) of the airflow passage 0IO held parallel to the plane containing the heating wire (5), and the direction of the airflow before entering the airflow passage 04 is perpendicular to the heating wire (5). The deflection angle θ that deviates from the direction along the heating wire in the vertical direction was set to six values, and the airflow velocity was measured for each of the six values.Figure 3 shows the measurement results, and the vertical axis shows the ρ11 constant. The wind speed (■) is plotted on the horizontal axis, and the deflection angle θ is plotted on the horizontal axis, and the measurement results of the anemometer of this example are shown by a solid line with a black circle, and those of the conventional one are shown by a broken line with a white circle.

As is clear from the diagram in Figure 3, the permissible deflection angle in the vertical direction of the airflow with small measurement error is 35 for the conventional product.
Invented products have a temperature of 70 to 10 degrees.
It is a degree, and inventions are broader.

Also, the direction of the airflow maintained at a constant speed of / Q mrx / Sea! The deflection angle α is such that the direction of the airflow before entering the airflow passage 04) is held parallel to a plane perpendicular to the heating wire (5) and deviates from the direction of the airflow passage 5-04) in a lateral direction perpendicular to the heating wire (5). was set to six values, and the airflow velocity was measured for each of the six values. Figure 3 shows the results of this measurement in the same manner as in Figure 3.

As is clear from the diagram in Figure 7, the allowable horizontal deflection angle of the airflow is about 25 to 30 degrees in the conventional product, whereas it is about 0 to 0 degrees in the invented product. , inventions are broader.

In addition, in the thermoelectric anemometer of this example, the airflow passage 04)
Since the cross-sectional shape of the is circular, unlike conventional products which are rectangular, it is possible to accurately measure wind speed even when the airflow is deflected in an oblique direction between the vertical and horizontal directions. , the allowable angle of deflection of the airflow in the oblique direction is estimated to be wide.

Second Embodiment (See Figures 5, 3, and q) The thermoelectric anemometer with the airflow passage structure of this example has a The provided introduction part OQ is formed into a conical cylinder shape or a Taber hole shape with an opening angle of O degrees. Other points are the same as those in the previous example, so the same reference numerals are given to FIG. S6- and the explanation thereof will be omitted.

For the thermoelectric anemometer of this example, experiments were conducted on the allowable deflection angle of the airflow in the same manner as in the previous example, and the measurement results shown in FIGS. 3 and 4 by the dashed line with half-black circles were obtained.

As is clear from the diagrams in FIGS. 3 and 3, the permissible vertical or lateral deflection angle of the air flow in the thermoelectric anemometer of this example is as wide as in the previous example.

In the thermoelectric anemometers of the above embodiments, if an airflow resistor such as a grid or a mesh is installed at the outlet of the airflow passage, if there is an object that disturbs the airflow near the outlet of the airflow passage, Airflow turbulence does not spread into the airflow path, allowing accurate measurement of wind speed.

The present invention provides a pP, electric couple, in which a heating wire that is electrically heated is stretched, and a high-temperature contact that has the same temperature as the heating wire that is cooled according to the speed of the airflow, and a low-temperature contact that has the same temperature as the airflow. constitutes,
In a thermoelectric anemometer in which a hood is provided to cover the high-temperature and low-temperature contacts of the thermocouple and the heating wire, and an airflow passage is formed that extends in the direction across the heating wire P, the cross-sectional shape of the airflow is circular. This is an air flow passage structure of a thermoelectric anemometer, characterized in that an introduction part is formed on the inlet side of the air flow passage, the diameter of which increases as it approaches the inlet.

This airflow passage structure has a wide allowable deflection angle for airflow with small measurement errors.

[Brief explanation of the drawing]

FIG. 7 is a partially longitudinal sectional side view of the air flow passage structure of the thermoelectric anemometer according to the first embodiment of the present invention, and FIG. 7 is a front view of the air flow passage structure. Figure 3 is a diagram showing the relationship between the measured wind speed V and the deflection angle θ in the vertical direction of the airflow in the invention and the conventional product, and Figure 1 is a diagram showing the relationship between the measured wind speed V and the horizontal direction of the airflow in the invention and the conventional product. FIG. 3 is a diagram showing the relationship of the deflection angle α to FIG. 5 is a partially vertical side view of the airflow passage structure of the thermoelectric anemometer according to the second embodiment of the present invention. 5: Heating wire 6, 7, 9, 11: Thermocouple 10: High temperature contact 12: Low temperature contact 13: Hood 14: Airflow passage 15: Inlet 16: Introduction part 9-

Claims (1)

[Claims] A thermocouple is constructed by installing a heating wire that is electrically heated, and has a high-temperature contact that has the same temperature as the KW wire that is cooled according to the speed of the airflow, and a low-temperature contact that has the same temperature as the airflow. In a thermoelectric anemometer in which a hood covering a pair of high-temperature and low-temperature contacts and a heating wire is provided to form an airflow passage extending in a direction transverse to the heating wire, the airflow passage has a circular cross-sectional shape,
An air flow passage structure for a thermoelectric anemometer, characterized in that an introduction part is formed on the inlet side of the air flow passage, the diameter of which increases as it approaches the inlet.