JP3488377B2 - Weather observation equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a meteorological observation device, and more particularly, to improving the followability of a device using a forced ventilation type ventilation tube to changes in outside air.

[0002]

2. Description of the Related Art As one type of meteorological observation device for measuring the temperature of air, that is, the air temperature, there is a device using a platinum resistance thermometer which utilizes that the resistance value of a platinum resistance temperature detector changes with temperature. Such a platinum resistance thermometer for weather observation has a resistance value of 92.02 Ω at -20 ° C and 1 at 0 ° C.
The one showing 00.00Ω and 107.93Ω at 20 ° C. is used, and the range from −50 ° C. to 50 ° C. can be measured by this. As a specific measuring method, as shown in FIG. 3, a constant current I is supplied from the constant current source 2 to the platinum resistance temperature detector 1, and the voltage V across the resistance body 1 is measured to obtain Pt = V / I
A four-wire measurement method for determining the resistance value Pt based on

By the way, the most important thing to measure the air temperature is that the temperature of the platinum resistance temperature detector must always be equal to the temperature of the surrounding air. It is not possible to measure the temperature accurately just by hanging it in a certain place.

Therefore, a ventilation tube having a structure as shown in FIG. 4 has been conventionally used. In FIG. 4, the ventilation cylinder is formed as a double cylinder composed of an inner cylinder 3 and an outer cylinder 4, and its lower end is open. Focusing on the upper ends of the inner cylinder 3 and the outer cylinder 4, the inner cylinder 3 is formed to be shorter than the outer cylinder 4, and the diameters of these upper ends are larger than the inner cylinder 3 but smaller than the outer cylinder 4. Fan 5 is installed. The fan 5 is rotationally driven by a motor 6 so as to suck air from the lower end. Further, a canopy 7 is provided so as to cover the motor 6, the fan 5 and the outer cylinder 4, and the lower end of the canopy 7 is hung outside the outer cylinder 4. On the other hand, focusing on the lower ends of the inner cylinder 3 and the outer cylinder 4, the inner cylinder 3 is formed longer than the outer cylinder 4. A platinum resistance temperature detector 1 is arranged in the inner cylinder 3 at a substantially central portion thereof.

In such a structure, the canopy 7 and the outer cylinder 4
Prevents solar radiation and other heat radiation, rain, and snow from entering the interior and directly hitting the platinum resistance thermometer sensor 1 to adversely affect the temperature. The inner cylinder 3 is the secondary radiation from the outer cylinder 4. The motor 6 and the fan 5 serve to blow a large amount of air to the platinum resistance temperature detector 1 to reduce the delay in response due to the heat capacity of the platinum resistance temperature detector 1.

Specifically, the canopy 7, the outer cylinder 4, and the inner cylinder 3 are made of a corrosion-resistant aluminum alloy or stainless steel material whose surface is sufficiently polished, and the influence of solar radiation and heat radiation from nearby objects is minimized. I am devising so that.

In other words, the canopy 7 and the outer cylinder 4 become higher in temperature than the ambient temperature during the day when they are directly exposed to the sun. At this time, if the inner cylinder 3 were not present, the platinum resistance thermometer sensor 1 would be affected by the secondary radiation from the inside of the outer cylinder 4 whose temperature was higher than the ambient temperature, and the temperature outside the true temperature of the air would be higher. The secondary radiation from the inside of the cylinder 4 indicates a higher temperature. The inner cylinder 3 is for preventing such secondary radiation from the inner side of the outer cylinder 4, and the outer side thereof is mirror-finished. The inner surfaces of both the inner cylinder 3 and the outer cylinder 4 are ideally black, which has high absorption efficiency for heat radiation.

This is based on the following reasons. When the secondary radiation from the inside of the outer cylinder 4 hits the inner cylinder 3, if the surface of the inner cylinder 3 is shining, it will be reflected by this surface and return to the inside of the outer cylinder 4, but the inside of the outer cylinder 4 will be reflected. If is black, the reflection will be absorbed. However, if the inside of the outer cylinder 4 is shining, it is further reflected and returns to the inner cylinder 3, resulting in multiple reflection, which adversely affects the inner cylinder 3.

Further, it is desirable that the inner cylinder 3 always has the same temperature as that of air, and for that purpose, it is important that the heat capacity is small, and it is desirable that the inner cylinder 3 be made of a member as thin as possible. Also, focusing on the streamline due to forced ventilation in the cylinder by the fan 5 shown by the arrow in the figure, the air very close to the outer cylinder 4 flows between the outer cylinder 4 and the inner cylinder 3, and general air is It is flowing into the cylinder 3. According to the actual measurement, when the wind duct receives strong solar radiation without wind, the surface of the wind duct may be higher than the temperature even by about 5 ° C. At this time, the temperature of the air in contact with the outer cylinder 4 rises and there is a risk that the ventilation cylinder will suck the air. However, by forming the lower end of the inner cylinder 3 slightly longer than the outer cylinder 4 as described above, The air having a high temperature in contact with the cylinder flows between the outer cylinder 4 and the inner cylinder 3, and the platinum resistance thermometer sensor 1 is exposed to a general air flow.
Here, the wind velocity flowing around the platinum resistance temperature detector 1, that is, the ventilation velocity, is designed to be 5 m / s or more by the motor 6 and the fan 5.

By the way, in such a structure, when viewed from the cylinder, the upper end is lightly closed and the lower end is open, and when the wind blows laterally from the lateral direction, negative pressure is generated at the lower end. If the natural wind becomes strong, it will flow backward in the direction opposite to the forced ventilation in the cylinder by the fan 5. As an example of wind tunnel test results, assuming that the ventilation speed in the ventilation cylinder when there is no wind is 5 m / s, when the wind speed reaches approximately 13 m / s, the ventilation speed in the ventilation cylinder becomes almost 0 m / s, and the wind speed becomes higher than that. It has been reported that it will regurgitate.

As a measure against backflow, it is sufficient to eliminate the negative pressure generated at the lower end of the ventilation tube by the natural wind hitting the ventilation tube. FIG. 5 shows an example of a ventilation tube provided with such a backflow prevention measure, which generates a negative pressure at the upper end to the same extent as the lower end, and the same reference numerals are given to the same parts as in FIG. There is. In FIG. 5, the upper end of the outer cylinder 4 is formed in a hemispherical shape so as to face the canopy 7, and a ventilation hole 8 is provided at the top. The radius of curvature of the hemisphere at the upper end of the outer cylinder 4 is smaller than that of the canopy 7, so that the distance between the canopy 7 and the hemispherical part at the upper end of the outer cylinder 4 is narrow at the central portion and becomes smaller on the outer periphery. It gets wider as you go.

In such a structure, when natural wind hits the ventilation tube laterally and flows between the canopy 7 and the hemispherical portion at the upper end of the outer tube 4, the pressure distribution based on Bernoulli's theorem is applied to this portion. Occurs, the wind velocity in the central portion becomes higher than that in the peripheral portion, and the pressure drops, so that the air inside the ventilation tube flows upward. On the other hand, when the natural air blows laterally on the ventilation tube, a negative pressure is generated at the lower end and the air in the cylinder flows out, but this is offset by the air flowing in the upper part, and inside the ventilation tube a constant amount by the motor 6 and the fan 5 is maintained. Ventilation speed can be obtained.

[0013]

However, according to these conventional devices, when the humidity is high, water droplets due to dew condensation are formed in the ventilation tube and the accommodating portion of the meteorological observation sensor such as the platinum resistance thermometer sensor 1. There is a problem that they adhere to each other and the followability of the measurement operation with respect to changes in the outside air is deteriorated.

The present invention has been made in view of such a point of view, and prevents adhesion of water droplets due to dew condensation to the inside of the ventilation tube and the accommodating portion of the weather observation sensor when the humidity is high, and changes in the outside air. It is an object of the present invention to provide a meteorological observation device capable of improving the followability of the measurement operation of the meteorological observation sensor with respect to.

[0015]

According to a first aspect of the present invention that achieves the above object, a motor is provided at one end of a ventilation tube formed in a tubular shape and having a weather observation sensor housed in its internal space. In a meteorological observation device configured to attach a rotationally driven fan to forcibly flow air into the ventilation tube, a humidity sensor housed in the internal space of the ventilation tube and a measurement signal of the humidity sensor. A motor control circuit for controlling the rotation speed of the motor according to the above, and when the humidity of the internal space of the ventilation tube exceeds a predetermined value for a predetermined time or more, the rotation speed of the motor is reduced to reduce the ventilation speed. This prevents dew condensation in the internal space of the ventilation tube.

In this type of device, a large amount of air is forcibly fed into the air duct when the motor rotation speed is high. When the humidity is high, dew condensation is likely to occur, and many water droplets adhere to the inside of the ventilation tube. These attached water drops tend to fall naturally, but it becomes difficult for them to drop due to the large amount of air blow, and the amount of water drops around the meteorological observation sensor increases, which reduces the responsiveness to temperature changes and the like.

On the other hand, in the present invention, when the humidity is high, the rotation speed of the motor is reduced in accordance with the measurement signal of the humidity sensor to reduce the amount of air blow, so that dew condensation becomes difficult. Even if dew condensation occurs, the amount of air blown is small, so that the water droplets tend to fall spontaneously, the amount of water droplets around the meteorological observation sensor decreases, and the responsiveness to temperature changes is improved.

The invention according to claim 2 of the present invention for achieving the above object is characterized in that, in the meteorological observation device according to claim 1, the meteorological observation sensor is a temperature sensor.

According to the present invention, highly accurate temperature measurement results in which the influence of dew condensation is reduced can be obtained. Of the present invention that achieves the above-mentioned object, the invention according to claim 3 is the invention according to claim 1 or 2.
The meteorological observation device described above is characterized in that the meteorological observation sensor and the humidity sensor are housed inside different ventilation ducts.

The present invention is effective when it is difficult to additionally install a humidity sensor inside an existing ventilation tube.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration explanatory view showing an embodiment of a meteorological observation device according to the present invention. In the figure,
The ventilation tube 9 is formed in a tubular shape, and a weather observation sensor 10 (for example, a platinum resistance temperature detector as a temperature sensor) and a humidity sensor 11 are housed in the internal space thereof.
A lower end of the ventilation tube 9 is opened, and a fan 5 which is rotationally driven by a motor 6 is attached to an upper end of the ventilation tube 9 so that air is forced to flow inside the ventilation tube 9 from the lower end to the upper end.

The humidity sensor 11 has, for example, a humidity of 0 to 100.
A DC voltage of 0 to 1 V is applied to the humidity detection circuit 13 constituting the motor control circuit 12 as a measurement signal corresponding to%. The humidity detecting circuit 13 configures the motor control circuit 12 with a power supply voltage switching signal for decreasing the rotation speed of the motor 6 to decrease the ventilation speed when the measurement signal of the humidity sensor 11 exceeds a predetermined value for a predetermined time or longer. Power supply control circuit 14. The power supply control circuit 14 switches the drive voltage of the motor 6 to either 12 V or 4 V to control the rotation speed of the motor 6, and switches the ventilation speed to either 6 m / s or 2 m / s. In the present embodiment, the drive voltage of the motor 6 is set to 12 V and the ventilation speed is 6 m / s in the steady state where the humidity is low.

The operation of the apparatus thus configured will be described with reference to the flowchart of FIG. Humidity sensor 11
Applies a measurement signal of DC voltage 0 to 1V corresponding to humidity 0 to 100% to the humidity detection circuit 13 at predetermined intervals (step ST1). The humidity detection circuit 13 sequentially compares the measurement signals of the humidity sensor 11 and determines whether or not the state of a DC voltage of 0.9 V or higher corresponding to a humidity of 90% continues for, for example, 10 seconds or longer (step ST2). If the humidity of 90% or more continues for 10 seconds or more, the power supply voltage switching signal for switching the drive voltage of the motor 6 to 4V is set so as to reduce the rotation speed of the motor 6 and reduce the ventilation speed to 2 m / s. Add to power control circuit 14 (step S
T3). On the other hand, if the humidity of 90% or more does not continue for 10 seconds or more, the drive voltage of the motor 6 remains 12 V and the ventilation speed continues to be 6 m / s (step ST4). Humidity sensor 1
This is executed every time 1 outputs a measurement signal.

In step ST3, the drive voltage of the motor 6 is switched to 4 V to reduce the ventilation speed to 2 m / s, so that the ambient air supplied to the surroundings of the meteorological observation sensor 10 in a high humidity condition is changed. The amount is simply 1/3
Condensation is less likely to occur, and the water droplets that have condensed become less likely to spontaneously fall because the ventilation speed is low, and the amount of water droplets around the meteorological observation sensor 10 decreases, and The tracking and response characteristics are improved and the measurement accuracy is also improved.

As described above, when the ventilation speed is reduced to 2 m / s, the measurement signal of the humidity sensor 11 is DC voltage 0.
When the voltage becomes 9 V or less, the humidity detection circuit 13 adds a power supply voltage switching signal for returning the drive voltage of the motor 6 to 12 V again to the power supply control circuit 14 so as to return the ventilation speed to 6 m / s.

In the above embodiment, the motor 6 is a DC motor and the motor control circuit 12 controls the drive voltage of the motor 6 by the power supply control circuit 14. However, for example, when the motor 6 is a pulse motor. The motor control circuit 12 may control the drive pulse of the motor 6.

A comparative measurement example of the recovery time from a high humidity state between the conventional weather observation device and the weather observation device according to the present invention will be described. In the experiment, use a ventilation tube for evaluation.
The sample was placed in a supersaturated atmosphere for a period of time and then left in a room at normal temperature and normal humidity to measure changes in temperature and humidity. Regarding the temperature change, measure the time until the difference between the measured temperature of the reference thermometer placed inside the room and the temperature inside the room is 0.5 ° C after being released from the supersaturated atmosphere into the room at room temperature and humidity. Regarding the humidity change, measure the time until the difference from the measured humidity of the reference hygrometer placed in the room is within 5% after releasing it from the supersaturated atmosphere to the room at room temperature and normal humidity. I decided to do it.

1) Temperature recovery time when ventilation speed 6m / s is fixed ... 25 minutes 2) Humidity recovery time when ventilation speed 6m / s is fixed ... 22 minutes When ventilation speed 6m / s is fixed As described above, since the amount of intake air is large, dew condensation is likely to occur when the humidity is high, and water drops adhere. The generated water drops tend to fall naturally, but they are hard to fall because they are ventilated from the lower end. A large amount of low-humidity air is blown into the ventilation tube by releasing it into the room, but since there are many water drops, the recovery time until the water drops decrease below a predetermined amount becomes long.

3) Temperature recovery time when ventilation speed is fixed at 2 m / s ... 26 minutes 4) Humidity recovery time when ventilation speed is fixed at 2 m / s ... 21 minutes When ventilation speed is fixed at 2 m / s Although the amount of intake air is small, it is affected by solar radiation and radiation, but even if the humidity is high, there is little condensation and the generated water drops easily fall naturally because the ventilation from the lower end is weak. When low-humidity air is blown into the ventilation tube by releasing it indoors, the amount of water droplets is small, but the amount of water drops rapidly to about 90% at the beginning of the release, but since there is little intake air, moisture near the suction port It is absorbed and reaches the vicinity of the sensor, causing a temporary increase in humidity. Also, recovery from the middle is slow. The recovery time for the water droplets to decrease below a predetermined amount becomes longer.

5) Temperature recovery time when the ventilation speed is variable ... 16 minutes 6) Humidity recovery time when the ventilation speed is variable ... A ventilation speed of 6 m / s is used for the performance during the recovery operation from high temperature and high humidity, and a ventilation speed of 2 m / s is used as the performance at the time of recovery from high humidity and high humidity. As a result, the recovery time from high humidity could be significantly shortened.

As is clear from the above, the recovery time is affected by the surrounding environment, particularly humidity, but the fact that the above-mentioned difference in the recovery time appears in the comparison test under the same environmental conditions is effective in the present invention. Means that.

Although FIG. 1 shows an example in which the ventilation cylinder is a single cylinder, the present invention can be applied to a conventional double cylinder structure.
By accommodating a temperature sensor as a meteorological observation sensor inside the space of the ventilation duct, highly accurate temperature measurement results with reduced influence of dew condensation can be obtained.

FIG. 1 shows an example in which the weather observation sensor and the humidity sensor are housed in a common ventilation tube. However, these sensors are housed inside different ventilation tubes arranged in the same environment. It is also possible to store each sensor in a separate ventilation tube in this way when it is difficult to additionally install the humidity sensor inside the existing ventilation tube.

Further, the present invention can be applied to the device having the structure for preventing negative pressure shown in FIG. 5, whereby a meteorological observation device having both measures against negative pressure and measures against dew condensation can be realized.

[0035]

As described above, according to the present invention,
A weather observation device that prevents water droplets from adhering to the inside of the ventilation tube and the storage part of the weather observation sensor due to dew condensation when the humidity is high, and improves the followability of the measurement operation of the weather observation sensor with respect to changes in the outside air. Can be provided.

[Brief description of drawings]

FIG. 1 is a configuration explanatory view showing an embodiment of a meteorological observation device based on the present invention.

FIG. 2 is a flowchart illustrating the operation of FIG.

FIG. 3 is an explanatory diagram of a 4-wire measuring method of a resistance temperature detector.

FIG. 4 is a structural explanatory view showing an example of a conventional double-tube ventilation tube.

FIG. 5 is a structural explanatory view showing an example of a conventional double-tube ventilation tube having a countermeasure against negative pressure.

[Explanation of symbols]

1 Platinum resistance thermometer 2 constant current source 3 inner cylinder 4 outer cylinder 5 fans 6 motor 7 canopy 8 holes 9 ventilation tube 10 Meteorological observation sensor 11 Humidity sensor 12 Motor control circuit 13 Humidity detection circuit 14 Power supply control circuit

Continuation of the front page (56) References JP-A-10-90074 (JP, A) JP-A-7-244008 (JP, A) JP-A-9-318139 (JP, A) Actually developed 62-22550 (JP , U) Actually open 5-90245 (JP, U) Actually open 60-134151 (JP, U) Actually open 3-83833 (JP, U) Actually open 6-31436 (JP, Y2) Actually open 6-42192 (JP, Y2) Jikkyohei 3-42343 (JP, Y2) Registered utility model 3006860 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01W 1/00-1 / 18 G01N 27/02 G01K 1/00-19/00 JISST file (JOIS)

Claims (3)

(57) [Claims] 1. A structure in which a fan driven by a motor is attached to one end of a ventilation tube formed in a tubular shape and having a weather observation sensor housed in an internal space thereof to force air to flow inside the ventilation tube. In the meteorological observation device, a humidity sensor housed in the internal space of the ventilation tube and a motor control circuit for controlling the rotation speed of the motor according to a measurement signal of the humidity sensor are provided, and the inside of the ventilation tube is provided. A meteorological observation device, characterized in that, when the humidity of the space exceeds a predetermined value for a predetermined time or more, the rotation speed of the motor is reduced to reduce the ventilation speed to prevent dew condensation in the internal space of the ventilation tube. 2. The weather sensor is a temperature sensor.
The meteorological observation device according to claim 1, wherein 3. The meteorological observation device according to claim 1, wherein the meteorological observation sensor and the humidity sensor are housed inside different ventilation ducts.