JPH0336899Y2 - - Google Patents

Description

[Detailed description of the invention] <Technical field> The present invention relates to a radiant temperature sensor, and in particular includes a hollow body made of a material that absorbs radiant heat, and a temperature sensing part of a thermometer is arranged inside the hollow body. The present invention relates to a radiant temperature sensor.

<Prior art> In this type of conventional radiant temperature sensor, the radiant temperature value changes due to the influence of airflow, so the radiant temperature value is corrected for the airflow as shown in the following equation.

mrt=tg+2.35√(tg−ta) where mrt is the average radiant temperature (℃), tg is the temperature indicated by the radiant temperature sensor (℃), ta is the dry bulb temperature (℃), and v is the air velocity (m/sec). That is, when the air velocity is 0, the temperature indicated by the radiant temperature sensor and the average radiant temperature are equal, and in other cases they are not equal. Therefore, as is clear from the above equation, in the conventional example, an airflow meter is required to measure and correct the airflow velocity, and it is necessary to perform complicated calculations. Even if it were possible to easily determine the average radiant temperature using a method, it would be complicated and expensive to manufacture because it would require an arithmetic device such as a microcomputer in addition to an airflow meter.

<Purpose> The purpose of the present invention is to eliminate the influence of airflow and accurately measure radiant heat, thereby making it simple and inexpensive to manufacture.

<Structure> In order to achieve the above object, the present invention is provided with a hollow body having radiant heat absorbing properties, a temperature sensing part of a thermometer is arranged in this hollow body, and the outer periphery of the hollow body is exposed to infrared rays. An airflow blocking cover made of a permeable material exists between the hollow body and the airflow blocking cover to cover a certain space in which the hollow body can thermally expand, and the airflow blocking cover is provided with air in the space. A vent hole is formed to communicate with the atmosphere to allow natural convection, and by blocking the air flow with the air flow blocking cover, the air flow velocity around the outer periphery of the hollow body is reduced to almost zero. The surrounding air pressure is made equal to the atmospheric pressure to prevent the surrounding air from expanding due to radiant heat and to prevent this heat from being trapped in the outer surroundings.

<Example> Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

The figure is a sectional view of the main parts of this embodiment. The radiant heat temperature sensor 1 of this embodiment has a spherical hollow body 2 made of a thin plate of a material with excellent radiant heat absorption properties such as copper, painted matte black, and a thermometer 3 inside the hollow body 2. A temperature detection section 4 is arranged.
The outer periphery of the hollow body 2 is covered with an airflow blocking cover 6 made of a material through which infrared rays can pass, such as glass or acrylic plate. A small space 7 is formed between the air flow blocking cover 6 and the hollow body 2, in which the hollow body 2 can expand thermally. That is, even if the hollow body 2 thermally expands, some space 7 still exists between it and the airflow blocking cover 6. Furthermore, this airflow blocking cover 6 has a plurality of holes, for example, two at the top and bottom in the figure, so that the air in the space 7 can naturally convect.
ventilation holes 8, 8 are formed. This ventilation hole 8,
8 equalizes the pressure of the air existing in the space 7 between the hollow body 2 and the airflow blocking cover 6 to atmospheric pressure, and causes natural convection of the air in the space 7 to form the outer periphery 5.
Even if the air expands due to radiant heat, the heat is not trapped in the space 7 so as not to interfere with the measurement of radiant heat.

Therefore, according to this embodiment, the airflow velocity around the outer circumference of the hollow body 2 becomes almost zero due to the airflow blocking cover 6, which eliminates the need to measure the radiant heat temperature in consideration of the influence of airflow, making it easy to It is possible to obtain a radiant heat temperature sensor 1 that is large and inexpensive to manufacture. Further, since the hollow body 2 is spherical, it indicates the average of radiant heat from all directions, so it becomes an accurate radiant temperature sensor.

In the above embodiment, a radiant temperature sensor that can measure the average radiant temperature was described. However, when measuring radiant temperature with a limited direction of radiation, the outer shape of the hollow body 2 should be rectangular or rectangular instead of spherical. Of course, other shapes may be used, and the outer shape of the airflow blocking cover 6 may also be rectangular or other shapes.

<Effects> As described above, according to the present invention, since it has the above-mentioned configuration, the airflow velocity around the outer circumference of the hollow body can be reduced to almost zero with the airflow blocking cover, which takes into account the influence of airflow. Eliminates the need for radiant heat temperature measurements. Therefore, there is no need for an airflow meter or complicated calculations for temperature correction that takes into account the influence of airflow, and there is also no need to perform this calculation using a calculation device such as a microcomputer, which simplifies the configuration. , and the manufacturing cost can be reduced. Furthermore, the air pressure in the space around the outside of the hollow body is made equal to atmospheric pressure by the vent holes, thereby preventing the air in this space from expanding due to radiant heat, thereby preventing heat from accumulating in the space.

[Brief explanation of the drawing]

The figure is a sectional view of a main part of an embodiment of the present invention. 1...Radiation temperature sensor, 2...Hollow body, 3...
Thermometer, 4...Temperature detection section, 6...Airflow blocking cover, 7...Space, 8...Vent hole.

Claims (1)

[Scope of utility model registration request] A hollow body 2 having radiant heat absorbing properties is provided, a temperature detection part 4 of a thermometer 3 is disposed inside the hollow body 2, and an airflow blocking cover made of a material through which infrared rays can pass is provided around the outer periphery of the hollow body 2. 6 exists between the hollow body 2 and the airflow blocking cover 6 to cover a small space 7 in which the hollow body 2 can thermally expand, and the air in the space 7 can naturally convect into the airflow blocking cover 6. A radiant temperature sensor formed with a vent hole 8 communicating with the atmosphere.