JP2915518B2 - Temperature compensation type oil detection sensor - Google Patents

Description

The present invention relates to a temperature-compensated oil detection sensor.

[Prior Art] Conventionally, as an oil detection sensor, for example, as shown in a side view in FIG. 6 and a longitudinal sectional view in FIG. 7, a cylindrical ceramic base material 01 has an oil detection section made of a carbon-containing silicon rubber thin film.
02, the tip and the base of the oil detecting part 02 are fixed to the ceramic base material 01 by the conductive adhesive 03, respectively, and the lead wire 04 is connected to the conductive adhesive 03, respectively. It has been known.

In this type of sensor, the oil detection unit 02 to which the oil 05 has adhered expands, and the electric resistance thereof increases, thereby detecting the oil 05.

However, such a structure has the following disadvantages.

(1) Since the coefficient of linear expansion and the rate of change in resistance of the oil detector 02 are large, they are affected by the effect of temperature rise, and it is difficult to detect minute oil.

(2) Since it is difficult to detect minute oil, oil cannot be detected in a vaporized gas state, and thus oil leak detection is slow.

[Problems to be solved by the invention]

The present invention has been proposed in view of such circumstances,
It is an object of the present invention to provide a high-performance temperature-compensated oil detection sensor that can detect a very small amount of oil, such as a vaporized gas, from oil smoke to liquid immersion at an early stage without being affected by a temperature change. .

[Means for solving the problem]

For this reason, the temperature compensation type oil detection sensor of the present invention is formed of the same material and dimensions as the sensor for oil detection of the carbon-containing silicon rubber type resistance conversion method on the same ceramic substrate, and the surface is made of a conductive material. A temperature compensation sensor covered with an electrically insulating and non-oil-absorbing material, and an oil detection amplifier for detecting a change in resistance of the oil detection sensor due to adhesion of oil or oil vaporized components. And a temperature compensating amplifier for detecting a change in resistance of the temperature compensating sensor accompanying a temperature change.

[Action]

According to the temperature compensation type oil detection sensor of the present invention described above,
Since the temperature compensation sensor is coated with a non-oil-absorbing material, even if oil or oil vaporized components adhere to the sensor, it does not penetrate to the silicon rubber part of the sensor,
The temperature compensation sensor is not affected by oil adhesion, but has the same degree of expansion as the oil detection sensor with respect to temperature changes.

Therefore, the detection value of the temperature compensation sensor having such characteristics, that is, the output of the temperature compensation amplifier, and the detection value of the oil detection sensor, that is, the output of the oil detection amplifier, are used as a differential means such as a differential amplifier. Thus, the detection value of the oil detection sensor can be compensated by the detection value of the temperature compensation sensor, and the influence of the temperature change of the oil detection sensor can be eliminated.

〔Example〕

FIG. 1 is an overall perspective view, FIG. 2 is a plan view, a side view and a bottom view of FIG. 1, and FIGS. III-II
FIG. 5 is a circuit diagram showing a sensor amplifier attached to the oil detection sensor of FIG.

First, in FIGS. 1 to 4, reference numeral 1 denotes a vertically long rectangular ceramic substrate formed of a ceramic having a low degree of thermal expansion, and reference numeral 2 denotes a thin film-like silicon rubber containing conductive carbon adhered along the left side of the ceramic substrate 1. The sensor 4 for detecting a vertically elongated strip-shaped oil is formed by bonding a silicon-containing silicon rubber 5 of the same material and shape as the silicon 8 aber 3 along the right side of the ceramics substrate 1 in a thin-film strip shape, and the surface thereof has a thin-film height. This is a vertically-strip-shaped temperature compensating sensor covered with a material 6 having electrical insulating property that does not adsorb oil such as a molecular adhesive.

Reference numeral 7 denotes terminals of the oil detecting sensor 2 and the temperature compensating sensor, which are fixed to the lead 13, as shown in FIG.
The ceramics board 1 is soldered to the circuit board 11 together with the leads 13, and furthermore, the OP amplifier IC 12 and other electronic parts are wired on the back side, these are arranged with the sensor portions of both sensors 2 and 4 at the top, Resin 8
The amplifier section is protected by filling. Reference numeral 10 denotes an output cable for outputting signals from both sensors 2 and 4.

Next, in FIG. 5, the oil detecting amplifier 16 of the oil detecting sensor 2 and the temperature compensating amplifier 17 of the temperature compensating sensor 4 are used to correct individual differences, that is, variations in the temperature characteristics of the sensors 2 and 4. And the output is adjusted by the variable resistor 15, respectively. Here, each sensor 2, 4 is amplifier 16, 17,
16 and 17 output a signal proportional to the resistance value of each sensor 2 and 4, and the amplifier 1
By inputting the outputs of 6 and 17 to the differential amplifier 18, the signal components due to the temperature change cancel each other out, and only the oil detection component is output to the output of the amplifier 18.

In such a structure, as shown in FIG.
Is deposited on the oil detection sensor 2 or the oil vaporized component 14
Adheres, the carbon-containing silicon rubber 3 swells and the distance between the carbon particles increases, so that the electric resistance changes.

On the other hand, in the temperature compensation sensor 4, as shown in FIG. 4, the carbon-containing silicon rubber 5 is covered with the oil adhesion preventing material 6 such as a polymer adhesive,
0. The oil vaporization component 14 does not penetrate into the silicone rubber and is therefore unaffected, but exhibits the same degree of expansion with temperature as the expansion due to temperature, as described above.

In such a relationship, the signal compensated for the change in the temperature resistance is accurately and quickly detected from the output of the differential amplifier 18 only when the influence of the oil is exerted.

According to this embodiment, the carbon-containing silicon rubber type resistance conversion type oil detecting sensor 2 laid on the ceramic substrate 1 and the same material and size as the oil detecting sensor 2 juxtaposed on the ceramic substrate 1 are used. And a temperature compensating sensor whose surface is covered with an oil adhesion preventing material such as a polymer adhesive, and the amplifiers 16 and 17 connected to the individual sensors are used to increase the sensitivity of both sensors. By using the same amplifier and using a differential amplifier 18, the effect on temperature can be negated, and a very small amount of oil, such as oil vaporized components, can be detected from oil smoke to immersion in a wide range of temperature conditions. It can be used.

〔The invention's effect〕

As described above, according to the present invention, the following effects can be obtained.

(1) A temperature compensating sensor is juxtaposed with an oil detecting sensor, so that oil adhesion can be quickly detected without being affected by temperature.

(2) Since the sensor unit and the amplifier unit have an integral structure and a temperature compensation circuit is inserted, it can be used under a wide range of temperature conditions.

(3) When the characteristics of the sensor can be finely adjusted in the amplifier circuit, a small amount of vaporized gas component of oil can be detected, and the accuracy is improved.

(4) It is possible to reduce the size by integrating the sensor itself and the amplifier.

[Brief description of the drawings]

1 is an overall perspective view showing one embodiment of the present invention, FIG. 2 is a plan view, a side view and a bottom view of FIG. 1, and FIGS. FIG. 5 is a circuit diagram showing a sensor amplifier attached to the oil detection sensor of FIG. FIG. 6 is a side view showing a known oil detection sensor, and FIG. 7 is a longitudinal sectional view of FIG. 1 ... ceramics substrate 2 ... oil detection sensor 3
... Silicone rubber with carbon, 4 ... Sensor for temperature compensation, 5 ... Silicone rubber with carbon, 6 ... Polymer adhesive, 7 ... Terminal, 8 ... High temperature resin, 9 ... Sensor case, 10 …… Output cable, 11 …… Circuit board,
12 OP amplifier (IC), 13 lead, 14 oil vapor component, 15 variable resistor, 16 oil detection amplifier, 17 temperature compensation amplifier, 18 differential amplifier, 20 ... oil,

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Yatabe 2-8-25 Shinhama, Arai-machi, Takasago-shi, Hyogo Takahashi Engineering Co., Ltd. (56) References JP-A-4-95762 (JP, A) Hei 3-70351 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01N 27/00-27/24

Claims (1)

(57) [Claims] 1. An oil detecting sensor of a carbon-mixed silicon rubber type resistance conversion type on a same ceramic substrate,
A temperature compensating sensor formed of the same material and dimensions as the sensor and covered with a heat conductive, electrically insulating and non-oil-absorbing material is provided side by side. An oil detection amplifier for detecting a change in resistance of the sensor due to adhesion of a component, and a temperature compensation amplifier for detecting a change in resistance of the temperature compensation sensor due to a change in temperature are provided. Compensated oil detection sensor.