JPH0326448Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a rain detector used to detect when it starts to rain.

For example, lighting windows installed on roofs and the like for lighting and ventilation are known. This lighting window is open on sunny days, but needs to be closed on rainy days. Therefore, in the past, the lighting windows had to be opened and closed manually using a window opening/closing rod or the like.
Recently, an electric window opening/closing device has been developed that automatically opens and closes windows by operating a switch located at hand.

When the window is opened and closed by the above method, when no one is in the room where the lighting window is installed, there is a risk that the user will not notice that it has started raining and the rain may fall into the room. In such a case, it is preferable to install a rain detection device to detect the beginning of rain and display a display or issue a warning to that effect.
Furthermore, in the case of an outdoor room, it is desirable to use an automatic lighting window that detects rain with a rain detector and closes the lighting window based on the signal. It would be effective to develop a rain detector that detects the onset of rain, as in this example.

The present invention was developed in view of the above circumstances, and is a combination of a heating element and a heat-sensitive element.By detecting the temperature when water droplets adhere to these elements, it is possible to detect rain. The present invention provides a rain detector that detects when it starts to rain.

The details of the rain detector of the present invention will be explained below based on the illustrated embodiments. FIG. 1 is a diagram showing the configuration of the rain detector of the present invention, in which 1 is a heat-sensitive element such as a temperature sensor, 2 is a heating element, and these are placed in contact with each other or close to each other as shown in the figure. . 3 is a detection circuit that receives the output from the heat-sensitive element and determines whether it is raining or not based on a change in the output; it is equipped with, for example, an amplifier, a differentiation circuit, etc., and amplifies the output from the heat-sensitive element, then differentiates it, and By comparing this differential value with a reference value, it is detected that it has started raining, and a signal based on this is output.

When the part of the rain detector configured as above, consisting of the heat-sensitive element 1 and the heating element 2, is installed outdoors in a place exposed to rain, the temperature near the heat-sensitive element 1, that is, the heat-sensitive element 1, is detected. The temperature is a certain temperature that depends on the outside air temperature and the temperature heated by the heating element 2. This temperature changes with changes in the outside temperature, but the changes are extremely slow. Therefore, the gradient of this change due to the outside temperature is extremely small, and the differential value in the detection circuit based on the output from the heat-sensitive element 1 at this time is extremely small. Therefore, if the level of the reference value with which it is compared is set high, the differential value will be less than the reference value. Here, due to rain, water droplets are applied to the heat-sensitive element 1.
When this happens, the temperature of the heat-sensitive element 1 drops rapidly.
Therefore, the gradient of temperature change becomes large and the differential value exceeds the reference value. Therefore, if the detection circuit emits a signal indicating that it has started raining when this reference value is exceeded, it is possible to know that it is raining. Since water droplets are always attached to the heat-sensitive element 1 while it is raining, the temperature in the vicinity does not change rapidly from the temperature when the water droplets first attach and fall. Therefore, since the gradient of the output fluctuation from the heat sensitive element 1 is also small, no signal is output from the detection circuit.

Next, when the rain stops and the water droplets no longer hit the heat-sensitive element 1, the moisture that has been attached to the heat-sensitive element 1 is heated by the heating element 2 and dries in a short time. Therefore, the temperature in the vicinity of the heat-sensitive element 1 rises and returns to the temperature of the outside air and the temperature caused by the heating of the heating element. Since the temperature change at this time is not very rapid, if the reference value of the detection circuit is set relatively high, there will be no output from the detection circuit.

In this way, according to the above-mentioned rain detector, when it starts to rain, the detection circuit outputs a signal to that effect, and based on this signal, a display is displayed, a warning is issued, or the window is automatically opened/closed. can operate the device.

In the embodiments described above, the temperature increase in the vicinity of the heat-sensitive element 1 due to heating by the heating element 2 does not have to be very high when the outside air temperature is high. That is, when the outside air temperature is high, even if there is not much heating by the heating element 2, when water droplets hit the heat-sensitive element 1, a sudden temperature drop occurs and a signal is output from the detection circuit 3. On the other hand, if the heating by the heating element is too high, the ambient temperature of the heat-sensitive element 1 may reach a high temperature of 100°C or more depending on the outside temperature, which may make some heat-sensitive elements unusable or reduce their durability. It is also undesirable due to gender issues.

However, in places where the outside temperature is low, unless the temperature is heated to a certain level, even if water droplets adhere to the heat-sensitive element due to rain, the temperature will not drop much, resulting in inaccurate detection. From this point of view, the higher the heating by the heating element 2, the better.

Considering these points, it is desirable that the heating element has a calorific value that increases the outside temperature by 30° to 40°C.

Rainfall can also be detected using a humidity sensor, but humidity sensors are generally sensitive to sunlight and have problems in terms of durability.

As explained in detail above, the rain detector of the present invention ensures rain detection by adding a heating element to the heat-sensitive element, and is extremely effective when used in, for example, an automatic window opening/closing device.

[Brief explanation of the drawing]

The drawing shows the configuration of an embodiment of the rain detector of the present invention. 1...Thermosensitive element, 2...Heating element, 3...Detection circuit.

Claims (1)

[Scope of utility model registration request] A rain detector includes a heat-sensitive element and a heating element placed close to the heat-sensitive element, and detects the onset of rain based on a temperature change detected by the heat-sensitive element.