JPH0642191Y2 - Ventilator for meteorological instruments - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a ventilation pipe for a meteorological observation instrument in which a sensor is arranged inside the pipe, and the crosswind disturbs the air flow inside the ventilation pipe to measure the temperature accurately. The present invention relates to an improvement of a ventilation tube structure that prevents the above-mentioned problem.

[Conventional technology]

A ventilation tube is installed almost perpendicular to the ground surface, and an electric fan is placed inside this ventilation tube to generate an air flow from the bottom to the top inside the ventilation tube so that it is exposed to this air flow. A ventilation cylinder type weather observation instrument in which a weather observation sensor such as a temperature sensor or a humidity sensor is arranged inside the ventilation cylinder is widely known. This structure is an excellent structure that can be easily attached to buildings and pillars, and can perform accurate meteorological measurements by removing the effects of sunlight and radiation from the ground surface.

It is known that this ventilation tube has a drawback that when a strong cross wind is received, the air flow inside the ventilation tube is disturbed and accurate measurement cannot be performed. That is, when a crosswind is received by the ventilation tube, the airflow inlet at the lower end of the ventilation tube is depressurized according to Bernoulli's principle, and the airflow toward the lower end of the ventilation tube is generated, reducing the action of the fan and sufficient airflow. Will not occur. In addition, when the cross wind is strong, the air flow inside the ventilation tube may be in a reverse flow state from top to bottom.

As a structure to prevent this, a structure is known in which the cross wind hits not only the lower end, which is the air flow inlet of the ventilation tube, but also the upper end, which is the air flow outlet, so that the effect of the cross wind is canceled at the top and bottom of the ventilation tube. (Japanese Utility Model Publication No. 57-39780).

[Problems to be solved by the device]

However, in this conventional example structure, an opening is also provided in the upper part of the ventilation tube to collect the crosswind and generate the decompression by being exposed to the crosswind, so that it is easily affected by rain such as intrusion of rainwater from the upper part. . In order to avoid this, there is a drawback that the structure of the roof provided on the upper part becomes more complicated, and the device becomes large in size.

The present invention is an improvement on this, and even if a cross wind occurs, the turbulence of the air flow inside the ventilation tube is small, accurate weather observation can be performed, and the device of a simple structure that is not affected by rain The purpose is to provide.

[Means for Solving the Problems]

The present invention is characterized in that a louver for receiving a cross wind and generating an upward airflow inside the ventilation tube is provided at the bottom of the ventilation tube.

It is preferable that the ventilation cylinder has a cylindrical shape and the louver has a conical surface that is coaxial with the cylinder and spreads downward.

[Action]

When a cross wind is received in the lower part of the ventilation tube, the louver changes the direction of the wind upward, and increases the velocity of the air flow supplied from the lower end of the ventilation tube according to the strength of the cross wind. Therefore, even if decompression occurs at the airflow intake due to the crosswind, the airflow supplied from below into the ventilation tube is increased against this, and the depressurized state is substantially canceled, and a large fluctuation in the internal airflow occurs. Try not to.

In the present invention, the louver is provided in the lower part of the ventilation tube, and the upper part of the ventilation tube does not need to be machined to introduce a cross wind, which is different from the conventional structure described above. This is superior to the above-described conventional structure in that the roof structure is simple, there is no risk of rain entering from the top, and it is not affected by rain.

〔Example〕

FIG. 1 is a cross-sectional structural view of a device of the present invention. In this example, a cylindrical ventilation tube 1 installed substantially vertically to the ground surface, and an electric fan 2 provided inside the ventilation tube 1 for generating an airflow from the lower side to the upper side inside the ventilation tube 1. And a ventilation tube type thermometer including a temperature measuring sensor 3 arranged inside the ventilation tube 1 so as to be exposed to the air flow. It is characterized in that a louver 4 for generating an upward airflow is provided inside. The louver 4 has a coaxial structure with the ventilation tube 1 and forms a conical surface that spreads downward.

The structure excluding this louver 4 is a conventionally known structure. The upper part of the ventilation tube 1 has a double roof structure so as to prevent rainwater from entering and discharge the airflow to the outside, and the electric signal output from the sensor 3 is an electric wire. Led to the outside.

In this structure, when a cross wind is received, the lower end of the ventilation pipe 1 is in a depressurized state, which obstructs the air flow from the bottom to the top of the ventilation pipe 1, but when the cross wind hits the louver 4, the cross wind changes its direction upward. Then, the air flows from the lower end of the ventilation pipe 1 into the inside thereof. Therefore, the depressurized state is substantially canceled out and the influence of the crosswind is hardly generated.

As is well known, the pressure reduction due to the cross wind generated at the lower end of the ventilation tube 1 is proportional to the square of the wind speed according to Bernoulli's principle. On the other hand, the amount of the air flow excessively supplied by the louver 4 is considered to be proportional to the wind speed. Therefore, by adjusting the size of the louver 4 and its position,
It is preferable to set the effective canceling action to be performed within the range of the wind speed at which the measurement is substantially performed. According to the experiments by the inventors, in the range of wind speed up to 50 m / sec, the fluctuation of the air flow inside the ventilation tube 1 remains in a small range that does not affect the measurement, and an extremely good result is obtained overall. Was given.

FIG. 2 is a structural diagram of another embodiment of the present invention. This figure shows only the lower end portion of the ventilation tube 1, and the louver 4 has a multi-stage structure so that the air flow inside the ventilation tube does not flow backward in a wider range of wind speed.

Although the above embodiment is a thermometer, the type of sensor installed inside is not directly related to the present invention, and various weather observation sensors can be arranged and used.

[Effect of device]

As described above, according to the present invention, the air flow inside the ventilation tube is less likely to be affected by the cross wind, and accurate weather observation can be performed. Further, as compared with the conventional device, it is not necessary to collect a side wind on the upper part of the ventilation tube, so that there is an excellent effect that the structure of the roof for preventing rainwater becomes simple.

[Brief description of drawings]

FIG. 1 is a perspective sectional structural view of an apparatus according to an embodiment of the present invention. FIG. 2 is a sectional view of the lower end portion of another embodiment of the present invention. 1 ... Ventilation tube, 2 ... Electric fan, 3 ... Sensor, 4 ... Louver.

Claims (2)

[Scope of utility model registration request] 1. Ventilation for a meteorological observation instrument, in which a sensor for a meteorological observation instrument is disposed inside, is installed substantially perpendicular to the ground surface, and a fan for generating an air flow from below to above is built in the inside. A ventilation tube for a meteorological observation instrument, characterized in that the tube has a louver at the bottom that receives a crosswind and generates an upward airflow. 2. The ventilation tube for a meteorological observation instrument according to claim 1, wherein the overall shape of the ventilation tube is a cylindrical shape, and the louver includes a conical surface that extends downward with a coaxial structure with the cylinder.