JPS5812129Y2 - Dew point detection element - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a dew point detection element.

A conventional element of this type uses a parallel capacitor made of metal flat plates facing each other and having air as a dielectric.

A dew point meter using such a detection element cools one electrode surface to cause dew to form on this surface, and measures the overall change in dielectric constant between the two electrodes caused by this condensation to determine the dew point. That's what I'm looking for.

Conventional elements of this type use parallel capacitors, so in order to detect minute amounts of dew, it is necessary to increase the plate area and narrow the distance between the plates to increase sensitivity.

However, due to the three-dimensional structure, it is very difficult to increase the area of the electrode plates and reduce the distance between the electrode plates in terms of manufacturing.

For commercial use, even if a narrow gap can be created, it must be possible for outside air to easily enter and exit between the electrode plates.

Corrosion of the exposed electrode plates is unavoidable, and sensitivity often decreases due to clogging of voids due to dirt and dust.

For this reason, frequent cleaning and inspection is required, but cleaning is difficult due to the delicate structure.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

Fig. 1 is a plan view showing an example of a dew point detection element that is the background of the present invention, Fig. 2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 is a partially enlarged view of section B in Fig. 2. .

In Fig. 1, the second recess, and Fig. 3, 1 is an insulating substrate;
2 is a detection unit for capacitance and temperature measurement, 3 and 4 are detection units 2
, and 5 is a temperature sensor for measuring the temperature of the detection unit 2 .

These electrodes 3 and 4 and the temperature sensor 5 are formed on the upper surface of the insulating substrate 1, and constitute the detection section 2.

Reference numeral 6 denotes an insulating film, and this insulating film 6 is formed on the upper surface of the insulating substrate 1 so as to cover the detection section 2, and this upper surface is used as a dew condensation surface 61.

7, 8 and 9, 10 are electrodes 3゜4 and temperature sensor 5
11 is a metal film bonded to the lower surface of the insulating substrate 1, and 12 is a ground wire of the metal film 11.

In the dew point detection element configured as described above, the insulating substrate 1, the insulating film 6, etc. are cooled by the cooling device 13 in the atmosphere to be measured, and the temperature of the atmosphere in contact with the dew condensation surface 61 is lowered to below the dew point. The dew 14 is made to condense around the nuclei of extremely small irregularities on the surface of the dew condensation surface 61.

Before the dew 14 is formed, most of the lines of electric force between the electrodes 3 and 4 pass through the dielectric insulating film 6 and the inside of the insulating substrate 1.

When the dew 14 is formed, many lines of electric force pass through the dew 14 because the dielectric constant of water is sufficiently larger than that of air, the insulating film 6, and the insulating substrate 1, and the insulating film 6 is sufficiently thin.

That is, the dielectric constant between the electrodes 3 and 4 changes greatly (the dielectric constant becomes large) due to the dew 14, and the capacitance between the electrodes 3 and 4 changes.

Condensation can be detected by measuring the capacitance change between the electrodes 3 and 4.

Further, when dew condenses, the surface temperature of the dew condensation surface 61 can be measured by the temperature sensor 5.

In this way, the dew point of the atmosphere can be determined.

As described above, the dew point detection element shown in FIG. 1 can be easily realized using known printing techniques, thin film manufacturing techniques, and the like.

The distance between electrodes 3 and 4 is extremely small (for example, 10 to 2
(approximately 0 μ), it is possible to detect minute dew condensation that is growing around the nucleus on the dew condensation surface 61, and it is possible to provide a highly accurate dew point detection element.

Furthermore, since the capacitance measuring electrodes 3 and 4 and the temperature sensing body 5 are formed on the same insulating substrate 1, it is compact and mechanically strong.

In use, unlike conventional parallel capacitors, there is no corrosion of the electrodes, and there is essentially no clogging of gaps due to dust, so cleaning and inspection are extremely easy.

Since the condensation surface 61 of the assembled detection element is open to the outside atmosphere, handling is easy! Furthermore, if the insulating film is constructed using an insulator with a sufficiently low dielectric constant, the change in capacitance will be significantly different between dew and frost, so it is necessary to distinguish between dew and frost due to supercooling. be able to.

This has been extremely difficult to achieve with conventional parallel capacitors, which have low sensitivity.

- Although the dew point detection element shown in FIG. 1 has many of the effects described above, the dew point detection element of the present invention is a further improvement of a part of the element shown in FIG.

That is, in the device shown in FIG. 1, it is necessary to form the temperature sensing body 5 on the insulating substrate 1, and this temperature sensing body 5 occupies a certain space.

The present invention makes it possible to measure the temperature of a dew condensation surface without providing the temperature sensor 5 shown in FIG. 1, thereby reducing the size and cost of the dew point detection element.

FIG. 4 is a diagram showing an example of a dew point detection element according to the present invention.

Components with the same numbers in FIG. 4 as those in FIGS. 1 to 3 are given the same numbers.

In FIG. 4, 31 and 41 are electrodes, and 81 and 91 are lead terminals of the electrode 31.

As shown in FIG. 4, the electrode 31 is usually made of copper or the like, and the resistance between the lead terminals 81 and 91 changes with the ambient temperature.

Therefore, the resistance value between the lead terminals 81 and 91 (electrode 3
The temperature of the condensing surface can be measured via the resistance value of 1).

Of course, condensation can also be detected by varying the amount between the electrodes 31 and 41.

In the above description, copper is used as an example of the constituent material of the electrode 31, but instead of copper, platinum, nickel, or the like may be used.

These materials are easy to use because the relationship between resistance value and temperature is clear.

Of course, the constituent material of the electrode 31 is not limited to the above, and any material may be used as long as it has conductivity and its resistance value changes with temperature.

As described above, according to the present invention, a dew point detection element having a very simple configuration can be realized.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an example of a dew point detection element which is the background of the present invention, Fig. 2 is a sectional view taken along the line AA in Fig. 1, and Fig. 3 is a
FIG. 4, which is a partially enlarged view of part B in FIG. 4, is a plan view showing an example of the dew point detection element according to the present invention. DESCRIPTION OF SYMBOLS 1... Insulating substrate transport 2... Detection part, 3, 4... Electrode for capacitance measurement, 5... Temperature sensor, 6... Insulating film, T~10... Lead terminal, 11 ...metal film, 1
2... Earth wire, 13... Cooling device, 14... Dew, 31.41... Electrode, 61... Dew condensation surface.

Claims (1)

[Claims for Utility Model Registration] An insulating substrate, a pair of electrodes 31.41 arranged close to each other on the insulating substrate, and the electrodes 31.41.
and an insulating film formed on the insulating substrate so as to cover the electrodes 31 and 41, detecting dew condensation by the change in capacitance between the electrodes 31 and 41, and detecting condensation on the surface of the dew condensation surface by the resistance value of one electrode 31 itself. A dew point detection element designed to measure temperature.