JPS5866044A - Humidity sensor - Google Patents

Abstract

PURPOSE:To reduce labor and cost of maintenance for the detecting part of a hygrometer by assemblying a humidity sensing element and an electrostatic capacity correction resistor into a unit and detatchably forming this unit within a circuit in the detecting part of the hygrometer. CONSTITUTION:A humidity sensing device comprises a supporting socket 1, a ring packing 2, a time constant output apparatus 3, a ring packing 4, a humidity sensor unit 5 and a gas permeable cover 6. The sensor unit 5 is provided with a humidity sensing element 34 of macromolecular film in a chamber surrounded by a gas permeable cylinder cell 18 and a gas permeable protector cap 19 and a correction electric resistor 32 fixed in a molding 33. The electric resistor 32 is formed a circuit of a predetermined time constant in an oscillation circuit of the time constant output apparatus 3, being assembled together with the electrostatic capacitor characteristic of the humidity sensing element 34. The above described constitution gives the sensor unit 5 interchangeability thereby the sensor unit can be more costsaving in maintainance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a humidity sensing device forming a detection section of an electric hygrometer.

Dry/wet bulb type hygrometers, which have been widely used industrially,
A wet bulb thermometer uses a sensing method to indirectly determine humidity based on the difference in temperature indicated, but a sensing method hygrometer uses
Since it is structurally equipped with a rod-shaped thermometer and an evaporative water container, (a) it requires a wide space for installation and reading, and (b) it is inconvenient to move, so in practice it can only be used stationary. (C) It cannot be used in narrow horizontal spaces. (d) It is cumbersome to replenish evaporated water and replace absorbent cloth. (e) It cannot be used in environments where water is averse. (f) telemetry is not possible; and-
It has many drawbacks, such as not being able to read the humidity just by looking at it.

On the other hand, as an alternative sensing method, an electric hygrometer is known, which uses a moisture-absorbing object exposed to the measurement atmosphere as a humidity-sensing element and detects humidity by its capacitance. When using the sensing method, it was difficult to manufacture an element having a constant capacitance under constant humidity.

For this reason, conventional electric hygrometers have the disadvantage that the detection section must be replaced with a new one every time there is a fluctuation or deterioration in measurement accuracy.

The present invention has been made to solve the above-mentioned drawbacks, and the purpose of the present invention is to provide a moisture-sensitive element,
By combining the electric resistance for capacitance correction into a unit, and by forming the sensor unit into a detachable circuit in the detection section, the effort and cost for maintaining the hygrometer detection section is greatly reduced. An object of the present invention is to provide a humidity sensing device that allows

The present invention will be described below based on illustrated embodiments.

As shown in FIGS. 1 to 8, the sensing device of the embodiment is a temperature sensing device assembled in the shape of a probe, and includes a support socket 1 disposed on the axis of the probe, and a ring backing. 2, time constant output device 3, ring backing 4
, a humidity sensor unit 5, and a breathable cover 6, and the formation mode of each unit will be described below.

(al, Support socket 1 A cylindrical body forming the base of the probe, with a circumferential step 1a formed in the middle of its inner hole, and a mounting screw lb with an external thread cut at the base end. ing.

A cabtyre conductor 7 guided to an external measuring section (not shown) passes through the center of the base end, and the socket 1 is fixed to a partition wall 9 with a mounting nut 8.

(b) Ring backing 2 This ring backing 2 is fitted onto the stepped portion 1a of the socket 1, and serves to seal the joint with the time constant output device 3.

(C), Time constant output device 3 The structure is an insulating cylindrical body 10 with a partition wall 10ai in the middle, and a post l protruding from the center of the partition wall 10a.
Ob's hole trap is a round bar-shaped electric temperature sensing element 11 (
The base half of the resistance temperature detector) is fixed with a nut 12,
In addition, three snap-type connector sockets 13 (of which only one is shown) are implanted at three locations σ around the partition wall 10a.

Further, a threaded ring 14 having an external thread is externally fitted and fixed on the outer peripheral surface of the cylindrical body 10, and a printed board 15 is spread on the end surface of the base side of the cylindrical body 10.

However, on this printed board 15, electrical members such as an oscillator 16 and their circuits are attached and formed, and the connector sockets 13 are electrically connected to the circuits.

Note that a large number of lug terminals 17 are provided on the outer surface of the printed board 15.
is provided protrudingly, and the oscillator circuit of the printed board 15,
The output circuit of the temperature-sensing element 11 is each lug terminal 1.
It is connected to the cabtyre conductor 7 via 7.

In addition, a backing 4 is fitted onto the inner peripheral edge of the open end surface of the cylindrical body 10.

+d+, ring-tsuya-tsuking 4 This nogu-tsuking 4 consists of a cylindrical body lO and a sensor unit 5.
In addition to sealing the joint with the
A hole 4a through which the socket 13 passes is bored on the periphery facing the book connector pin 13.

(e) Humidity sensor unit 5 The sensor unit 5 includes an air-permeable cylinder container 18 sintered into a cylindrical shape, and a similar air-permeable protective cap 19 covering the tip opening of the container 18. An insulating ring holder 20 fitted into the half of the cap 19 of the container 18, an insulating presser ring 21 sandwiched between the holder 20 and the cap 19, and the output of the container 18. The circuit board 22 is fitted inside the vessel 3 and is formed by an insulating circuit board 22, a partition plate 23, and a spacing tube 24 assembled into an H-shaped cross section. At three locations on the circumferential line of pin 25
, 26 and 27 pass through the partition plate 23.

Note that the ring holder 20 and the circuit board 22 are connected by a coupling screw 28.
By being tightened, the circumferential stepped portion of the shilling container 180 is held in place.

Furthermore, a pin hole that communicates with the circuit board 2'2 passes through one location on the circumferential line of the ring holder 20, and a conductive pin 29 is embedded in the pin hole and is snapped into place. A short round rod-shaped conductive rubber seat 30 is press-fitted between the head of the pin 29 and the bottle hole opening.

Further, a similar conductive rubber seat 31 is embedded in a position symmetrical to the rubber seat 30 of the holding ring 21, and a correction pad is provided between the partition plates 23 of the circuit board 22. The electric resistor 32 is attached, and the annular space between the circuit board 22 and the partition and plate 23 is solidified with a molding material 33.

Here, the moisture sensing element 34 (FIGS. 6 and 7) interposed between the ring holder 20 and the presser ring 21 will be explained.

This element 34 has a thickness of 10
A polymer film of about μm size is used.

Specifically, Au coated electrodes 36 and 37 having a thickness of approximately 100λ are deposited on the exposed portions of the central inner circle on each of the front and back surfaces of the circular resin film 35, and each electrode 36. For example, T-shaped terminal portions 36a and 37a, each having a thick Au film deposited thereon, are formed in symmetrical locations of the terminal portions 37 in an overhanging manner, and the element 34 is connected to each terminal portion 36a.

37a is placed in pressure contact with each of the conductive rubber seats 31 and 30 at approximately the center thereof.

Next, on the circuit board 22, a time-determined element circuit (FIG. 8), that is, a parallel circuit of capacitance C and electric resistance R, is formed between the connector pin 25 and the common connector pin 27. is through the pattern of the conductive rubber seat 30°31, the conductive bottle 29, the cap 19, the cylinder body, and the circuit board 22,
A capacitance C between both electrodes 36 and 37 is introduced, and a resistance R of a resistor 32 is introduced between the connector pin 26 and the common connector pin 27.

With such a circuit configuration, C and R as time constant elements are electrically inserted into the oscillation circuit of the time constant output device 3 via the connector socket 13.

), breathable cover 6 This cover is sintered into a pot shape, and has a mounting screw 6a cut on the inner edge of the opening, and this screw 6a connects to the output device 3.
It is screwed into the threaded ring 14 of.

Note that multiple types of equally shaped covers with different ventilation characteristics are prepared and attached to this cover 6, and when assembling the cover 6, the cover corresponding to the required sensitivity response can be selectively used. be done.

Finally, for the resistor 32 assembled in the humidity sensor unit 5, a resistor element having a different resistance value is used for each unit, that is, the resistance value of the resistor 32 of each unit 5 is A resistance value is selected that, in combination with the capacitance characteristic value of each humidity sensing element 34, forms a circuit with a predetermined time constant in the oscillation circuit of the time constant output device 3.

Next, the operation of the sensing device according to the embodiment in which the above-mentioned members are coupled as shown in FIG. 2 will be explained.

Breathable cover 6, cylinder container 18, and cap 1
9 have air permeability through the pores created during sintering, so the space in which the humidity sensing element 34 and the temperature sensing element 11 are placed is kept in a state equal to the temperature and humidity of the outside air. Therefore, the film 35 of the humidity sensing element 34 absorbs moisture corresponding to the humidity of the outside air, and as a result, the time constant output device 3 outputs a capacitance C and a correction resistance that are correctly correlated to the humidity of the outside air. A Noculus width signal based on R is output.

Furthermore, an external measuring device (not shown) connected to the conductor 7 performs the above-mentioned integration operation of the e pulse width signal and the temperature sensing element 1.
Since the resistance value measurement operation of 1 is performed, the sensed humidity value and temperature value are correctly read by the measuring device.

Note that the configuration of the embodiment does not necessarily require the installation of the temperature sensing element 11 and its wiring; however, if the structure described above also serves as a temperature measurement, it is possible to accurately measure the temperature of the humidity sensing element 34. Since it can be measured, it has the advantage of accurately detecting the amount of moisture in the outside air.

By the way, if you use the sensing device of the example for a long time,
Fluctuations or deterioration may occur in the adsorption/mixing performance of the film 35 of the moisture-sensitive element 34, which may cause an error in the measured values. This operation is extremely simple, and the cost of the sensor unit 5 is low, so maintenance of the device does not require much cost.

By the way, the device of the embodiment can be fixedly attached to a wall surface as shown in FIG. 1, and can also be attached to a hand-held rope as shown in FIG. The leading end of the grip 38 having a longitudinal cylindrical shape may be screwed onto the mounting screw 1a of the support socket 1, and then the conducting wire 7 may be passed through the grip 38.

Next, in the configuration of the embodiment described above, the moisture sensitive element 34
Although the structure is such that the humidity sensor is placed vertically with respect to the axial direction of the device, it is also possible to place the humidity sensor horizontally with respect to the axial direction as shown in FIGS. 10 to 12. In the form of the unit 40, a long box-shaped air permeable container is divided into upper and lower parts, that is, a bottom container 41 and a vapor container 42 made of a sintered resin material are attached together with screws 43. A sensing chamber 44 is formed by cutting out a half of the split container, and inside the sensing chamber 44 is a pair of upper and lower insulating press rings 46 for holding the moisture sensing element 45.
47 is housed, and three connector pins 48, 49, and 50 are sandwiched in the other half of the split container and protrude in the longitudinal direction. A correction electrical resistor 51 is placed in the space.

Thus, the electrode terminal portions 52 and 53, which are vapor-deposited on the upper and lower surfaces of the element 45 and extend in a V shape, are electrically connected to the pin 48 through the conductive rubber seat 54. Further, the terminal portion 53 on the lower surface is electrically connected to the pin 50 via a conductive rubber seat 55.

On the other hand, each lead of the resistor 51 is electrically connected to the intermediate pin 49 and the common pin 5o.

It goes without saying that this unit 40 is used by being connected to a time constant/number ratio device (not shown) having a flat rectangular box shape, and its operation is as described above. There is no change in sensor unit 5.

As described above, according to the humidity sensing device according to the present invention, the air-permeable container, the humidity sensing element having a high molecular weight resin film as a moisture absorbing body, and the correction electric resistor are assembled into a single unit. At the same time, the sensor unit is connected to the time constant output device that forms the signal output section of the device to form the device, making it possible to make the sensor units compatible. In addition to providing a highly stable and reliable hygrometer, this method also has the effect of improving the maintainability of the sensing device.

[Brief explanation of the drawing]

``'' Figure 1 is a front view of a humidity sensing device showing one embodiment of the present invention, Figure 2 is a sectional view of the same, Figure 3 is an exploded view of Figure 2, and Figure 4 is an exploded view of the humidity sensing device. 3 is an enlarged view of the sensor unit, FIG. 5 is an external view of the same, FIG. 6 is a partially enlarged view of the moisture sensing element in FIG.
9 is a circuit diagram of a time-determining element circuit, FIG. 9 is a diagram showing another installation mode of the same embodiment, FIG. 10 is a side view of a sensor unit showing another embodiment, and FIG. 11 is a diagram of a sensor unit showing another embodiment. , same top view, 1st
FIG. 2 is a plan view of the moisture sensitive element of FIG. 11. 3... Time constant output device, 5, 4o... Sensor unit, 18... Cylinder container, 25, 26, 27, 48° 49.50... Connector bin as a connector terminal,
32.51... Electrical resistor, 34.45... Moisture sensitive element, 35... Film, 36.37... Electrode, 41.42... Bottom container and lid container, 52.53.
...Electrode terminal part. Patent applicant Chino Seisakusho Co., Ltd.

Claims (1)

[Claims] Equipped with a humidity sensor unit and a time constant output device, and
The sensor unit includes a breathable container exposed to the outside air and a
, is an element placed in the same container, and is combined with a moisture-sensitive element having a pair of coated electrodes adhered to both sides of a polymer film, and the capacitance characteristic value between the two electrodes. A correction electrical resistor for forming a circuit with a predetermined time constant, and a connector terminal for connecting the circuit to the output device are assembled as a single unit. , a humidity sensing device characterized by being detachably formed on the meter.