JPH02755B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heat sensor with improved corrosion resistance.

[Background technology]

Conventionally, as a heat sensor 1 having corrosion resistance including acid resistance and alkali resistance, for example, as shown in FIG. For the cap, alumite-treated corrosion-resistant aluminum was used, and for alkali resistance, a stainless steel cap 4 was used. Similarly, the heat-sensitive plate 3 is made of corrosion-resistant aluminum treated with alumite for acid resistance, and tin-plated stainless steel is used for alkali resistance. However, these materials (particularly stainless steel) have low thermal conductivity, which has been an obstacle to increasing heat detection sensitivity.

On the other hand, as shown in FIG. 2, in the case of a heat sensor 6 using a thermistor 9 as a heat-sensitive element,
A titanium material is used for the cap 10, but although the thermal conductivity is acceptable, the problem is that it is an expensive material. In addition, the metal parts exposed to the outside must have pressure resistance between them and the internal circuit of the sensor, so contact between the heat-sensitive element, heat-sensitive plate, and cap is avoided, which reduces thermal conductivity and reduces detection sensitivity. I couldn't raise it.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a heat sensor that has excellent corrosion resistance and detection sensitivity, and is made of an inexpensive material.

[Disclosure of the invention]

The heat sensor 11 will be described below with reference to FIGS. 3 and 4 of an embodiment of the present invention. The heat sensor 11 houses a printed board 15 constituting a signal processing circuit in the main body 14, and conducts electricity from the printed board 15 with a lead wire 12b. A connected thermistor 12a is provided to protrude from the main body 14. This thermistor 12a and lead wire 12b
The tip end including a part of the lead wire 12b is sealed with glass 12, and the lead wire 12b is sealed with ceramics 13. 16
is a protector that protects the thermistor 12a. The main body 14 and the protector 16 are made of plastic material. Ceramics 1 mentioned above
The main body 14 of No. 3 is press-fitted or sealed to prevent a corrosion-resistant atmosphere from entering inside the main body 14.

With the above-described structure, the metal parts are not exposed to the atmosphere at all, so there is no problem with corrosion resistance. Furthermore, when this glass-encapsulated thermistor 12a is used, there is no need to electrically float the glass 12 and the thermistor 12a to withstand pressure, so heat is transferred directly and the detection sensitivity is higher than that of the conventional titanium one.

The present invention can be used in constant temperature spot type, differential spot type, and compensated spot type heat sensors by simply changing the signal processing circuit.

〔Effect of the invention〕

As described above, the thermistor is arranged so as to protrude from the sensor body, and the lead wire is electrically connected to the printed board of the sensor body, and the area around the thermistor and the lead wire are sealed with different materials, and the material around the thermistor is heated. The lead wire portion is made of a highly conductive material, the material of the lead wire portion is at least a material with lower thermal conductivity than the material near the thermistor, the material near the thermistor and the material of the lead wire portion are closely bonded, and the lead wire portion is made of a material with a high conductivity. The other end of the material is press-fitted or sealed into the hole in the body so that the corrosion-resistant atmosphere does not flow into it, so it is acid-resistant and
A heat sensor with a low-cost heat-sensitive element part that is strong in both alkali resistance and corrosion resistance and has excellent detection sensitivity has been realized, which is industrially useful.

[Brief explanation of drawings]

Fig. 1 and Fig. 2 show a conventional example, Fig. 1 is a partially sectional front view of a heat sensor, and Fig. 2 is a partially sectional front view of another conventional heat sensor. It is. 3 and 4 show embodiments of the present invention,
FIG. 3 is a front view in full section, and FIG. 4 is a perspective view. DESCRIPTION OF SYMBOLS 11...Heat sensor, 12...Glass, 12a...Thermistor, 12b...Lead wire, 13...Ceramics, 14...Main body.

Claims (1)

[Claims] 1 The thermistor is placed so as to protrude from the sensor body, electrically connected to the printed board of the sensor body using a lead wire, and the area around the thermistor and the lead wire are sealed with different materials, and the material around the thermistor is made of thermally conductive material. The material of the lead wire portion is made of a material having at least lower thermal conductivity than the material near the thermistor, the material near the thermistor and the material of the lead wire portion are closely bonded, and the material of the lead wire portion is A heat sensor characterized in that the other end is fitted into a hole in the body by means such as press-fitting or sealing to prevent a corrosion-resistant atmosphere from entering.