JPH0637321Y2 - Temperature and humidity sensor - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a temperature and humidity sensor for measuring temperature and humidity, and more specifically, to temperature and humidity of general air conditioners, factory air conditioners, biotechnology, agricultural houses, various chambers, etc. The present invention relates to a temperature / humidity sensor used for measuring humidity and controlling the temperature / humidity of the atmosphere.

"Prior art" In recent years, using a humidity detecting element in which electrodes are attached to ceramics or resin, a change in electric resistance of the humidity detecting element which changes according to ambient humidity is detected by a signal and the humidity is measured at the same time. A temperature / humidity sensor that also measures a temperature using a temperature detection element such as a resistance temperature detector is widely used as a sensor for various air conditioning systems.

The humidity detection element of this type of temperature / humidity sensor deteriorates the measurement accuracy due to dust in the atmosphere adhering to the surface after long-term use. For this purpose, a heating mechanism such as a coil heater and a ceramic heater for heating is integrally attached to the humidity detecting element, and the dirt adhering to the humidity detecting element after heating for a certain period of time is removed by heating to restore the accuracy and reliability of the detection signal. Is mandatory.

Further, the humidity detecting element, the heating mechanism and the temperature detecting element are entirely surrounded by a protector having a mesh shape, a cylindrical shape with a window, a hollow spherical head shape or the like in order to protect them from external stress, dust and the like.

"Problems to be solved by the invention" In the above conventional temperature and humidity sensor, when the dirt of the humidity detecting element is removed by heating, the gas around the humidity detecting element is also heated, and this heated gas is protected. It moved to the vicinity of the temperature detecting element by convection inside the tool. For this reason, the temperature detecting element is also heated, and there is a problem that the temperature of the external atmosphere to be originally measured cannot be accurately measured until the gas is cooled after the heating is completed.

The present invention has been made to solve the above problems, and provides a temperature / humidity sensor capable of accurately measuring both temperature and humidity immediately after the dirt of a humidity detecting element is removed by heating. The purpose is to

"Means for Solving Problems" A temperature / humidity sensor comprising a humidity detecting element integrally attached with a heater for removing dirt by heating, a temperature detecting element, and a hollow cylindrical protector surrounding these, The humidity detecting element is supported by a supporting member so that a gas is interposed between the humidity detecting element and the inner surface of the hollow tubular protector, and the temperature detecting element detects the humidity in the tubular protector. The cylindrical protective equipment is provided at intervals in a column, and a ventilation hole for the humidity detection element is provided at a position near the humidity detection element of the tubular protective equipment, and a ventilation hole for the temperature detection element is provided at a position near the temperature detection element. It is characterized by

"Function" Even if the gas around the humidity detecting element is warmed when the dirt is heated and removed by the heater, the ventilation hole for the humidity detecting element is provided at a position near the humidity detecting element of the tubular protector. The heated gas is ventilated with the gas outside the tubular protective equipment. Further, since the temperature detecting element ventilation hole of the tubular protective equipment is provided at a position in the vicinity of the temperature detecting element side which is arranged at a distance from the humidity detecting element, the external condition of the tubular protective equipment is always maintained. Gas flows in from. Due to the synergistic effect of the humidity detecting element vent hole and the temperature detecting element vent hole, the temperature detecting element is not heated by the heated gas around the humidity detecting element.

As a result, the temperature / humidity sensor of the present invention can accurately measure both temperature and humidity immediately after the dirt on the humidity detecting element is removed by heating.

Thus, heat transfer from the vicinity of the humidity detecting element to the vicinity of the temperature detecting element is mainly due to heat conduction through the protective equipment, so the thermal conductivity of the protective equipment is 19 × 10 ^-3 J / cm ・ s ・
If a material of k or less is applied, the difference in temperature between the temperature detecting element and the external atmosphere can be further eliminated.

[Embodiment] FIG. 1 is a sectional view of a main part of a temperature / humidity sensor showing an embodiment of the present invention.

Reference numeral 1 is a plate-shaped humidity detecting element made of Al ₂ O ₃ —SnO ₂ —TiO ₂ -based ceramics or the like, 2 is a ceramic heater made of ceramics such as alumina, and a heating resistor (not shown) is formed inside , 3 and 3'fix the humidity detecting element 1 which is thin-film printed on the upper and lower surfaces of the humidity detecting element 1 to the ceramic heater 2 and extract the electric resistance value which changes according to the ambient humidity from the humidity detecting element 1. Electrodes made of a resistance material, 4 are made of platinum and have an electric resistance of 100Ω and a temperature detecting element 5 mechanically fixes the temperature detecting element 4, and the humidity detecting element 1, the ceramic heater 2 and the temperature detecting element 4 are connected to an external circuit. An electrically insulating substrate in which a conductor for electrically connecting is formed, 6 denotes a thermal conductivity of 1.4 for protecting the humidity detecting element 1, the ceramic heater 2, the temperature detecting element 4 and the electrically insulating substrate 5. ^{10 -3 J / cm · s ·} k of polyacetal or thermal conductivity ^{245 × 10 -3 J / cm ·} s · k resistant steel cylindrical protective equipment, 7,7 'are side protection 6 Ventilation holes for the humidity detection element for introducing the external gas provided on the side to the humidity detection element 1 side, 8 and 8'for introducing the external gas provided on the side surface of the protector 6 to the temperature detection element 4 side. Ventilation holes for temperature detecting elements for the operation, 9 is a mesh-like support plate that is adhered to the inner surface of the protector 6 and fixes the ceramic heater 2 and the humidity detecting element 1, and the temperature and humidity sensor 10 as a whole. Constitute.

In the temperature / humidity sensor 10 of this embodiment, when the cigarette tar or the like adheres to the humidity detecting element 1 due to long-term use and the measurement accuracy is deteriorated, the ceramic heater 2 is energized to set the humidity detecting element 1 to 500 Heat to about 1 minute. This removes the dirt adhering to the surface of the humidity detecting element 1 and restores the measurement accuracy. Even if the gas around the humidity detecting element 1 is heated when the dirt is heated and removed, it is heated because the humidity detecting element ventilation holes 7 and 7'are provided in the vicinity of the humidity detecting element 1. The gas and the gas outside the protective equipment 6 are ventilated. Further, since the temperature detecting elements 4 arranged in the humidity detecting element 1 at intervals in a vertical column are provided with the temperature detecting element ventilation holes 8 and 8'in the vicinity thereof, the protective device is always provided. 6 Gas from the outside flows in. Due to the synergistic action of the humidity detecting element vent holes 7 and 7'and the temperature detecting element vent holes 8 and 8 ', the temperature detecting element 4 is not heated by the heated gas around the humidity detecting element 1.

As a result, the temperature / humidity sensor 10 of the present invention can accurately measure both temperature and humidity even immediately after the dirt on the humidity detection element 1 is removed by heating. Next, the temperature / humidity sensor of the present embodiment. The test results of 10 will be described with reference to FIG. Here, as Example B, the protector 6 for the temperature and humidity sensor is set to have a thermal conductivity of 1.4 × 10 ⁻³ J / cm · s ·
k of polyacetal, and as Example B, the thermal conductivity of the protector 6 is 245 × 10 ⁻³ J / cm · s ·
The test was conducted on the one constituted by k heat resistant steel.

Here, the temperature and humidity sensor 10 of Example A and Example B is set to a temperature of 25.0.
After placing it in a thermostat set at ℃ and a wind speed of 0.3 m / sec and connecting it to an indicator equipped with an arithmetic circuit so that the signal taken out from the temperature detection element 4 can be converted into a temperature display, energize the ceramic heater 2 and set the humidity. FIG. 2 shows the results of measuring the change over time in the temperature display from the start of energization when the temperature of the detecting element 1 was raised to 500 ° C. and energization was stopped after 1 minute.
Curve A is Example B (polyacetal protective equipment), Curve B is Example B (heat-resistant steel protective equipment)].

For comparison, a temperature / humidity sensor having the same configuration as the temperature / humidity sensor using the heat-resistant steel protective equipment of the present embodiment B except that the temperature detection element ventilation holes 8 and 8 ′ are not provided ( The results of measuring the change with time of the temperature display using (not shown) are also shown in FIG. 2 (curve C in FIG. 2).

As can be seen from Fig. 2, a temperature / humidity sensor (heat-resistant steel protector) that does not have a vent hole for the temperature detection element is used for about 10 minutes after the heating is finished
However, the maximum error was 30.1 ° C and the maximum error was 5.1 ° C. On the other hand, the temperature / humidity sensor 10 of Example B (heat-resistant steel protector) with the ventilation hole for the temperature detection element has a maximum of 2
It showed 8.2 ℃, and the maximum error remained at 3.2 ℃.

In this embodiment, the humidity detecting element 1 is provided with the humidity detecting element vent holes 7 and 7 ', and the temperature detecting element 4 is provided with the temperature detecting element vent holes 8 and 8'. , The conduction of heat through the gas is hindered. For this reason,
The movement of heat is mainly due to the heat conduction through the protector 6, and as can be seen from the measurement results of Example B (polyacetal protector), if a material having low thermal conductivity is used for the protector, almost no error occurs. (Max 0.4 ℃). Therefore, if a material having a thermal conductivity of 19 × 10 ⁻³ J / cm · s · k or less (for example, quartz glass) is applied to the protector, the error can be further reduced.

[Advantage of Device] As described above, according to the temperature / humidity sensor of the present invention, both the temperature and the humidity can be accurately measured even immediately after the dirt on the humidity detecting element is removed by heating.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of a temperature / humidity sensor of the present invention, and FIG. 2 is a temperature converted based on a signal taken out from the temperature / humidity sensor by placing the temperature / humidity sensor in a thermostatic chamber. The result of having measured the time-dependent change of a display is shown. 1 ... Humidity detection element, 2 ... Ceramic heater, 4 ...
Temperature detecting element, 6 ... Protective equipment, 7,7 '... Ventilation hole for humidity detecting element, 8,8' ... Ventilation hole for temperature detecting element, 9 ... Mesh support plate

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-49-68783 (JP, A) JP-A-58-22944 (JP, A) JP-A-58-139058 (JP, A) JP-A-59- 91349 (JP, A) Actual development Sho 58-151845 (JP, U)

Claims (2)

[Scope of utility model registration request] 1. A humidity detecting element integrally provided with a heater for removing dirt by heating, a temperature detecting element, and a hollow cylindrical protector surrounding these elements, wherein the humidity detecting element is a cylinder. The temperature detecting element is supported by a supporting member so as to interpose gas between the temperature detecting element and the inner surface of the cylindrical protector, and the temperature detecting element is arranged in the cylindrical protector in a longitudinally spaced manner from the humidity detecting element. A temperature / humidity sensor, characterized in that a ventilation hole for a humidity detection element is provided at a position near the humidity detection element of the protector, and a ventilation hole for a temperature detection element is provided at a position near the temperature detection element. 2. The protective member has a thermal conductivity of 19 × 10 ⁻³ J / cm · s ·
The temperature and humidity sensor according to claim 1, wherein the temperature and humidity sensor is made of a material of k or less.