JP3878875B2 - Oxygen concentration meter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oxygen concentration meter for measuring the oxygen concentration in a low-melting-point liquid metal such as lead / bismuth, bismuth, or lead.
[0002]
[Prior art]
As shown in FIG. 3, conventionally, an oxygen concentration contained in molten lead / bismuth b is measured using an oxygen concentration meter 1 in an atmosphere of an inert gas a. In FIG. 3, 2 is a container or apparatus, 3 and 4 are normal leads, and 5 is a measuring instrument.
[0003]
As shown in FIG. 2, the oxygen concentration meter 1 has an alumina housing 7 inserted into the tip of a hollow tubular extension sleeve 6 made of austenitic stainless steel, and molybdenum ( A counter electrode 8 made of molybdenum having a counter electrode lead wire 13 made of Mo) and a standard electrode 9 are attached. The standard electrode 9 includes a measurement unit 10 having a long and thin container shape like a test tube formed of a solid electrolyte such as yttria stable zirconia, and a standard electrode c accommodated in the measurement unit 10. In the case, a standard electrode lead wire 14 made of molybdenum is inserted.
[0004]
However, in the conventional oximeter 1, the joint 15 between the housing 7 and the counter electrode 8, the joint 16 between the housing 7 and the container-like measuring part 10, and the joint 17 between the housing 7 and the extension sleeve 6 are respectively ceramic cement d. As a result, it was difficult to ensure airtightness, and there was a problem with long-term durability. In particular, it was difficult to maintain the airtightness of the joint portion 16 of the housing 7 and the container-like measurement unit 10.
[0005]
Therefore, it can be used in an atmosphere of an inert gas, but in an atmosphere of a reducing gas or an oxidizing gas, the standard electrode c stored in the container-shaped measuring unit 10 is reduced or oxidized, so that accurate oxygen can be obtained. The concentration cannot be measured.
[0006]
Furthermore, since the two lead wires 13 and 14 of the counter electrode and the standard electrode are accommodated in the extension sleeve 6, it is difficult to ensure insulation between these two lead wires 13 and 14, and Since the electromotive force is not stable due to the interaction between the lead wires 13 and 14, it is difficult to accurately measure the oxygen concentration.
[0007]
This type of oxygen concentration meter is configured to measure the oxygen concentration of the molten metal b by measuring the voltage E between the standard electrode c and the molten metal b. This principle can be explained with a schematic diagram of an oximeter (see FIG. 4).
For the left electrode in the figure, Equation 1
O ₂ (P ₁ ) + 4e ⁻ = 2O ²⁻ (1)
For the electrode on the right side of the figure, Equation 2
^{_{2O 2- = O 2 (P 2}} ) + 4e - ····· (2)
・ The overall reaction is as shown in Equation 3.
[0008]
O ₂ (P ₁ ) = O ₂ (P ₂ ) (3)
Therefore, since the electromotive force E (Formula 4) corresponding to the oxygen partial pressure difference is generated, the oxygen concentration of the molten metal can be measured by measuring the electromotive force E.
[0009]
E = (RT / 4F) × In (P ₁ / P ₂ ) (4)
here,
R: Gas constant or gas constant (8.3144 mol ⁻¹ K ⁻¹ )
T: Temperature (K)
F: Faraday constant (96485 mol ⁻¹ )
In: Natural logarithm P ₁ : Oxygen partial pressure on the measurement side (here, oxygen partial pressure of molten metal / lead / bismuth)
P ₂ is the oxygen partial pressure of the standard electrode.
[0010]
[Problems to be solved by the invention]
The present invention has been made to solve such a conventional problem, and improves the sealing performance between the sleeve and the housing, between the housing and the container-shaped measuring section, between the housing and the counter electrode, and two The main object is to provide an oximeter capable of suppressing problems between lead wires.
[0011]
In order to solve such a problem, the present invention is configured as follows. That is, the oxygen concentration meter according to the first aspect of the present invention is an oxygen concentration meter for measuring the oxygen concentration in a liquid metal or molten metal of lead / bismuth, bismuth, lead , and is a hollow tubular extension sleeve A corrosion-resistant sleeve is fixed to the tip of the anti-corrosion sleeve, and an elongated container-shaped measuring unit made of a solid electrolyte is attached to the tip of the corrosion-resistant sleeve, and a standard electrode is housed in the container-shaped measuring unit, and the standard electrode In the oximeter in which a standard electrode lead wire is inserted through the sleeve and a counter electrode lead wire is connected to the extension sleeve, a hole having a diameter larger than the inner diameter of the corrosion resistant sleeve is formed on the lower surface of the corrosion resistant sleeve. The opening of the container-shaped measuring portion is inserted into the hole and joined by an in-row joint structure, and the gap between the hole of the corrosion-resistant sleeve and the container-shaped measuring portion is hermetically bonded. It is characterized in that sealing by Kushiru.
[0013]
An oximeter according to a second aspect of the invention is characterized in that, in the oximeter according to the first aspect, the extension sleeve and the corrosion-resistant sleeve are coupled by welding or a gas tight joint. Yes.
[0014]
An oximeter according to a third aspect of the present invention is the oximeter according to the first or second aspect, wherein the corrosion-resistant sleeve is made of ferritic stainless steel.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
In FIG. 1, 1a is an oxygen concentration meter for measuring the oxygen concentration in low melting point liquid metals such as lead / bismuth, bismuth, lead and the like.
[0018]
The oxygen concentration meter 1a includes a corrosion-resistant sleeve 19 formed of a corrosion-resistant steel material such as ferritic stainless steel, martensitic stainless steel, or chromium molybdenum steel at the tip of a hollow tubular extension sleeve 6 formed of austenitic stainless steel. Are welded.
[0019]
An elongated container-shaped measuring unit 10 is inserted at the tip of the corrosion-resistant sleeve 19 like a test tube made of a solid electrolyte such as yttria stable zirconia. More specifically, a hole 20 having a diameter larger than the inner diameter is provided on the lower surface of the corrosion-resistant sleeve 19, and the opening side of the container-shaped measuring unit 10 is inserted into and coupled to the hole 20. In addition, the gap is sealed with a sealing material d ′ such as a hermetic seal or ceramic cement.
[0020]
The standard electrode c is accommodated in the container-shaped measuring unit 10, and a standard electrode lead wire 14 made of molybdenum is inserted into the molten standard electrode c through the hole 11 in the sleeves 6 and 19. Furthermore, here, as an example, the counter electrode lead wire 4 is connected to the outside of the extension sleeve 6.
[0021]
In the figure, 21 is an alumina insulating tube for insulating the standard electrode lead wire 14, and 22 is an alumina seal for sealing the upper end of the extension sleeve 6. Here, as the standard electrode, Bi / Bi ₂ O ₃ , Pb / PbO, In / In ₂ O ₃ , Sn / SnO, or the like is preferably used.
[0022]
As described above, according to the present invention, the corrosion-resistant sleeve 19 and the container-shaped measuring unit 10 are firmly coupled by the inlay joint structure, and the joint is sealed with a sealing material d ′ such as a hermetic seal or ceramic cement. Therefore, it is excellent in airtightness, and accurate measurement is possible even in an atmosphere of reducing gas or oxidizing gas. Further, for the same reason, it is excellent in long-term durability. Further, since the two lead wires are provided separately inside and outside the extension sleeve 6, the stability of the electromotive force can be ensured and accurate measurement can be performed.
[0023]
【The invention's effect】
As described above, the present invention is an oxygen concentration meter for measuring the oxygen concentration in a low melting point liquid metal such as lead / bismuth, bismuth, lead, etc., and a corrosion-resistant sleeve is provided at the tip of a hollow tubular extension sleeve. An elongated container-shaped measuring unit made of a solid electrolyte is attached to the tip of the corrosion-resistant sleeve by an inlay joint structure, and a standard electrode is accommodated in the container-shaped measuring unit, and further, the standard electrode is accommodated in the standard electrode. The lead wire for the standard electrode is inserted through the lead wire, and the lead wire for the counter electrode is installed separately.
[0024]
As described above, in the present invention, the corrosion-resistant sleeve and the container-shaped measuring part are firmly bonded by the inlay joint structure, and further, the joint part is sealed with a sealing material such as a hermetic seal or ceramic cement. Airtightness is excellent, and accurate measurement is possible even in an atmosphere of reducing gas or oxidizing gas. Further, for the same reason, it is excellent in long-term durability. Furthermore, since the two lead wires are provided separately inside and outside the extension sleeve, the stability of the electromotive force can be ensured and accurate measurement can be performed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an oximeter according to the present invention.
FIG. 2 is a cross-sectional view of a conventional oxygen concentration meter.
FIG. 3 is a schematic view of a conventional oxygen concentration measuring apparatus.
FIG. 4 is a schematic diagram of an oxygen concentration meter.
[Explanation of symbols]
b Low melting point liquid metal such as lead / bismuth, bismuth, lead c Standard electrode 1a composed of lead / bismuth Oxygen concentration meter 3 Lead wire 6 for counter electrode Extension sleeve 10 Elongated container-shaped measuring unit 14 composed of solid electrolyte For standard electrode Lead wire 19 Corrosion resistant sleeve

Claims (3)

An oxygen concentration meter for measuring the oxygen concentration in lead / bismuth, bismuth, lead liquid metal or molten metal , with a corrosion-resistant sleeve fixed to the tip of a hollow tubular extension sleeve, Along with the attachment of a long and narrow container-shaped measuring section made of a solid electrolyte, a standard electrode is accommodated in the container-shaped measuring section, and a lead wire for a standard electrode is inserted into the standard electrode through each sleeve. In the oximeter in which the lead wire for the counter electrode is connected to the extension sleeve, a hole having a diameter larger than the inner diameter of the corrosion-resistant sleeve is provided on the lower surface of the corrosion-resistant sleeve, and the opening side of the container-shaped measuring unit is provided in the hole. Oxygen concentration characterized by being inserted and joined by an in-row joint structure, and the gap between the hole of the corrosion-resistant sleeve and the container-like measuring part is sealed with a hermetic seal . 2. The oximeter according to claim 1, wherein the extension sleeve and the corrosion-resistant sleeve are coupled by welding or a gas tight joint . 3. The oxygen concentration meter according to claim 1 , wherein the corrosion-resistant sleeve is made of ferritic stainless steel .

Images