JPH0632614Y2 - Sensor element of hydrogen sensor for molten metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a sensor element of a hydrogen sensor for molten metal.

(Prior Art) The inventor of the present application previously proposed a hydrogen sensor for molten metal. The sensor element of this conventional hydrogen sensor for molten metal is as shown in FIG. 1, and a solid electrolyte chip 11 was fitted to the tip of a cylindrical refractory tube 12 and then connected to a lead wire 15. Insert standard pole metal 14 and then fill it with insulating powder 13,
4 and the lead wire 15 are fixed, and the rear end of the fireproof tube 12 is closed by a sealing lid 16 made of cement-containing refractory material or the like, and the lead wire 15 is projected.

However, according to this structure, as the fixed insulator 13 of the standard electrode metal 14 and the lead wire 15, powder of refractory material such as alumina or magnesia was used. However, when the insulating refractory powder was charged, it was necessary to perform tapping for about 15 seconds to perform a close packing operation. If the filling is insufficient, the fixation of the standard electrode metal 14 becomes unstable and the lead wire 1
There was a possibility of causing the cutting trouble of No. 5.

In addition, since the standard electrode metal 14 is in a molten state during use, there is a problem of poor contact with the solid electrolyte chip 11, such as penetration into the insulating powder 13 very easily. Further, on the principle of this hydrogen sensor, when the measured molten metal and the standard electrode metal 14 have the same temperature, the hydrogen content is obtained from the Nernst equation. A low material structure was desired for this fixing insulator.

(Technical problem) This invention is technically capable of omitting tapping work, improving fixation of lead wires, eliminating contact failure, and significantly reducing thermal conductivity to shorten response time. It is an issue.

(Technical Means) The present invention was made in order to solve the above technical problems. The sensor element of the present invention will be described below with reference to the embodiments shown in the drawings. First, in the embodiment shown in FIG. A solid electrolyte chip 1 made of an oxide such as strontium or cerium at the tip of the inside (Japanese Patent Laid-Open No. 58-50
And oxides essentially the same as those disclosed in S.
r Cei-x MxO ₃ -α is represented by the general formula, M is Y, Sc, Yb, Nd, Pr, Mg or Zn;
x is a numerical value of 0.5 or less, and d is a numerical value of 0 to 0.5. ) Is then fitted, and then the standard pole metal 4 (for example, aluminum, copper or the like having a known hydrogen content is used) connected to the lead wire 5 is inserted, and then the standard pole metal 4 and the lead wire 5 are inserted. As the insulating material for fixing, first, the refractory wool 7 on the side of the standard electrode metal 4 and then the heat insulating tube 3 are arranged by inserting them into the lead wires 5, respectively, and the standard electrode metal 4 and the lead wire 5 are fixed, and the cement Sealing lid 6 made of refractory material
Then, the rear end of the fireproof tube 2 is closed, and the lead wire 5 is projected to the outside.

Next, in another embodiment of FIG. 3, the solid electrolyte 1 is formed into a bottomed tube having a closed bottom end, and the standard pole metal 4 connected to the lead wire 5 is inserted into the inner tip of the bottom end tube. The refractory wool 7 and the heat insulating tube 3 are sequentially arranged in the above, the rear end is closed by the sealing lid 6, and the lead wire 5 is projected.

That is, this invention uses a solid electrolyte chip made of an oxide such as strontium or cerium for a hydrogen sensor for molten metal, and in a sensor element, as an insulator for fixing the standard pole metal and the lead wire, a fireproof wool and It is characterized in that the heat insulating pipes are respectively inserted through the lead wires.

In addition, mullite fiber or alumina fiber is used as the refractory wool, and the heat insulating tube is also porous with alumina or mullite and has a tubular shape with a through hole for guiding the lead wire in the center. Can be used.

(Effect of the Invention) The present invention, which is configured as described above, has an effect that the tapping action which has been conventionally performed can be omitted and the reliability of fixing is increased. In addition, the cushioning property of fire-resistant wool can support the heat-insulating pipe by frictional force (holding force) between it and the wall surface of the fire-resistant tube, and prevent the penetration and mixing of the melted standard polar metal during measurement. You can
Furthermore, the use of refractory wool and heat insulation pipes can reduce the thermal conductivity to a very low level, enabling the melting of the standard electrode metal and the time to reach the same temperature as the molten metal to be measured, that is, the response time to be shortened. did.

By the way, in Fig. 4, the insulating powder as a conventional product is filled with 100 mesh powder of mullite and has a specific gravity of 1.3, and the response time is 18 seconds. Using mullite with a specific gravity of 0.2,
The heat-insulating tube is formed by molding mullite powder into a porous material, firing it, and applying a material having a specific gravity of 0.8. The graph shows the relationship between the electromotive force and the response time, which showed a response time of 10 seconds.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a conventional sensor element, FIG. 2 is a vertical sectional view of an embodiment of the sensor element of the present invention, FIG. 3 is a vertical sectional view of another embodiment of the same, and FIG. It is a chart showing the relationship with the response time for the conventional product and the product of the present invention. 1, 11 ... Solid electrolyte chip, 2, 12 ... Fireproof tube, 3 ... Insulation tube, 13 ... Insulating powder. 4,14
...... Standard pole metal, 5,15 ...... Lead wire, 6,16 ......
Sealing lid, 17 ... Fireproof wool

Claims (1)

[Scope of utility model registration request] 1. A sensor element using a solid electrolyte chip made of an oxide such as strontium or cerium for a hydrogen sensor for molten metal, wherein a refractory wool from the standard pole metal side is used as an insulator for fixing the standard pole metal and the lead wire. A sensor element for a hydrogen sensor for molten metal, characterized in that a heat insulating tube is inserted through each lead wire.