JPS6156783B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a consumable probe for measuring temperature, oxygen, carbon concentration, etc. by immersing it in molten metal.

Conventionally, a consumable probe that is immersed in molten steel to measure temperature, oxygen, carbon concentration, etc. is composed of a sensor serving as a detection part and a protection tube for protecting a holder from the heat of the molten steel. In this case, the material of the protection tube is paper to make the probe inexpensive, and the wall thickness is kept to the minimum thickness depending on the purpose of measurement, which is the difference with most expendable probes. This can be said to be common to both. For this reason, it is not always possible to sufficiently protect the inside of the probe from the effects of heat, and the paper tube is rapidly heated due to heat transfer from the side and tip of the probe, generating water vapor, combustion gas, etc. This will contaminate the area around the connector, causing a drop in insulation and causing measurement errors.

Measurement probes include dedicated probes that measure any one of temperature, oxygen concentration, carbon concentration, etc., and composite probes that combine two or three of these to perform simultaneous measurements. FIG. 1 shows such a probe 1 set in a holder 2 and immersed in molten steel 4 of a converter 3 for measurement, and the measurement is carried out manually or by machine.

FIG. 2 shows the state before such immersion measurement. In this state, the probe 1 is set in the holder 2, and the paper tube 20 is used as the protective tube of the probe 1. When immersed in molten steel in this state, the paper tube 20 of the probe 1 is rapidly heated, the moisture absorbed by the paper tube 20 turns into water vapor, and the adhesive used during manufacturing also burns and turns into gas. Most of it will be ejected into the molten steel, but a considerable amount will also be ejected inside the paper tube 20. The water vapor, combustion gas, etc. spouted inside the paper tube 20,
The area near the connector between probe 1 and holder 2 is filled with water, wetting and contaminating the connector. That is, the vicinity of the contact 5 of the connector 17 attached to the rear end of the sensor 11 or the contact 5' of the socket 6 attached to the tip of the holder 2 is filled with contaminants. Connector 17 got wet during measurement.
If contaminated, the insulation will deteriorate, resulting in a decrease in measurement accuracy and poor indication.If the situation worsens, a short circuit will occur and measurement will become impossible. Even when the amount of water vapor, combustion gas, etc. ejected is small, repeated measurements will cause this phenomenon to accumulate due to adhesion and condensation near the contact 5' of the socket 6, which is the connector of the holder 2, and in severe cases. becomes tar-like,
Even if a new probe is installed, the electrical connection will be incomplete and measurement errors will occur as well.

As a countermeasure for these improvements, even if a gasket is installed near the connector to prevent water vapor, combustion gas, etc. from filling the vicinity of the connector during measurement, when the probe 1 is removed from the holder 2, it may adhere to the vicinity of the connector of the holder 2. It condenses and accumulates through repeated measurements, and in severe cases it becomes tar-like, resulting in exactly the same results as described above.

Such problems always occur when using conventional probes, and other examples of conventional consumable probes are shown in FIGS. 3, 4, and 5. The probe shown in FIG. 3 has the paper tube 20 as it is, and the probe shown in FIG. The probe shown in FIG _. 5 has a coating 22 made of hard mold material, and the probe shown in FIG. However, in both cases, when immersed in molten steel, the insulation effect was small, and it was inevitable that water vapor, combustion gas, etc. would blow out inward due to the heating of the paper tube.

Moreover, reduction in measurement accuracy, defective measurement instructions, and even inability to measure with consumable probes
This poses major obstacles to steelmaking operations, such as reduced efficiency, reduced quality, and increased measurement costs.

The purpose of the present invention is to provide a consumable probe that is immersed in molten metal, particularly molten steel, to measure temperature, oxygen concentration, carbon concentration, etc., and to eliminate water vapor generated from a paper protective tube used in the probe during immersion measurement. The object of the present invention is to provide a consumable probe that can prevent insulation deterioration at a connector caused by wetting or contamination near the probe and connector due to combustion gas, etc., and can perform highly accurate and stable measurements.

Therefore, according to this invention, the first invention is:
A consumable probe consisting of a sensor, a holder, and a paper tube whose outer peripheral surface is coated with ceramic fiber to protect them, as the probe:
A consumable probe characterized in that a sensor, a ceramic housing, a plastic housing, and a connector are sequentially arranged from the tip thereof, and the plastic housing and the paper tube are connected and arranged, A second invention is a consumable probe similar to the first invention, in which a sensor, a ceramic housing, and a connector are sequentially arranged from the tip of the probe, and moisture and gas are absorbed into the inner surface layer of the paper tube. It is characterized in that an impervious material layer is integrally formed, a gap is provided between the paper tube and the coated ceramic fiber, and the plastic housing and the paper tube are connected and arranged. It provides a consumable probe.

Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 6 is an explanatory diagram showing a cross-sectional view of an embodiment of the consumable probe according to the first aspect of the present invention.
Incidentally, the same parts as those of the conventional example shown in FIGS. 1 to 5 are given the same reference numerals, and the explanation thereof will be omitted.

In order to prevent insulation deterioration in the vicinity of the connector caused by water vapor, combustion gas, etc. generated from the paper tube, first, in order to prevent water vapor, combustion gas, etc. from being generated from the paper tube, especially the inner paper tube 18, It has a structure that prevents heat from being transmitted to the tube 18, that is, the outer periphery of the body and the tip of the probe have an insulating structure. That is, in the body of the probe, a commercially available ceramic fiber 16, which is a highly refractory insulating material, is provided around the outer periphery of a paper tube 18 with a thickness of 5 mm and a length of 200 mm. A plastic housing 15 made of heat-resistant plastic is provided behind the ceramic housing 14 so that the paper tube 18 does not come into direct contact with the high ceramic housing 14, and the paper tube 18 is brought into contact with this plastic housing 15. The heat of the ceramic housing 14 is directly transmitted to the paper tube 18.
This was done so that it would not be transmitted to the public.

With this structure, even though the ceramic fiber 16 is thin and short,
The inner paper tube 18 is sufficiently insulated to serve its purpose.

That is, the basic structure of the first consumable probe of the present invention is: firstly, the probe structure includes a sensor, a ceramic housing, a plastic housing, and a connector arranged in this order from the tip; and secondly, a ceramic housing, a plastic housing, and a connector. This is based on two points: the housing structure has a heat-resistant plastic housing at the rear of the ceramic housing, and the paper tube is connected to the plastic housing without coming into contact with the ceramic housing.

Furthermore, the basic configuration of the second consumable probe of the present invention is: firstly, the sensor, ceramic housing, and connector are sequentially arranged from the tip, and secondly, the probe is configured such that a sensor, a ceramic housing, and a connector are sequentially disposed in the inner surface layer of the paper tube. Secondly, two or more layers of material impermeable to moisture and gas are integrally formed. Thirdly, a gap is provided between the paper tube and the coated ceramic fiber. Fourthly, the ceramic housing and the paper tube are separated from each other. It is basically based on four points connected and arranged.

Therefore, in order to understand the heat insulation effect of the consumable probe of the present invention, a,
Thermocouples (chromel/alumel thermocouples) were embedded in each position b, c, d, and e, and the probe was immersed in molten steel at 1600°C to measure the temperature inside the probe. The graph of FIG. 7 shows the temperature change over time within the probe in the example of FIG. 6 obtained as a result.

As is clear from the graph in FIG. 7, within about 30 seconds after the probe is immersed, the temperature at any part of the inside of the paper tube 18 is less than 100°C, and the paper tube 1
It is presumed that almost no water vapor or combustion gas was generated from No. 8.

On the other hand, regarding the conventional consumable probe shown in FIGS. 2 to 5, a sixth
The graph in FIG. 8 shows the temperature change over time in the probe obtained by embedding a thermocouple (chromel/alumel thermocouple) in substantially the same manner as in the example shown in the figure and immersing it in molten steel at 1600°C.

According to this result, with the conventional probe, A,
The insulation effect increases in the order of B, C, and D, but in any case, the inside of the probe reaches 100℃ or more after about 15 seconds, and the temperature rise gradient is also steep, so It is easily inferred that water vapor, combustion gas, etc. will be generated. The graph in FIG. 8 also shows curve b for the probe of the present invention, which has the lowest heat insulation effect in the graph in FIG. Therefore, the high heat insulation effect of the consumable probe of this invention is recognized, especially as a probe that requires a long time for immersion measurement, usually 15 to 20 seconds.
The effects of the consumable probe of the present invention are remarkable.

Based on the basic structure of the present invention as described above, in order to prevent insulation deterioration near the connector due to water vapor, combustion gas, etc. generated from the paper tube, even if water vapor or combustion gas is generated, it is necessary to prevent it from blowing out inside the paper tube. It's fine if you don't have it. The specific content of this was disclosed in Japanese Utility Model Application Publication No. 119976/1983 by the same applicant, but by combining it with the heat insulating structure of the present invention, the effect of preventing insulation deterioration in the consumable probe is even more remarkable. Become something. That is, in the second invention of the present invention, a thin metal tube or metal foil is provided in the inner surface layer of the paper tube, and the paper tube is also made into a multiple tube with a double structure or more, and a gap is formed between the paper tubes. The water vapor, gas, etc. generated thereby are blocked from being ejected into the probe with a metal foil or the like, and are then discharged to the outside through the gaps between the sheets.

The embodiment of the second invention of the present invention using such multiple tubes and a paper tube having a barrier layer such as metal foil is described in the ninth embodiment.
As shown in the figure.

In FIG. 9, an aluminum foil 19 is provided in the inner surface layer of the paper tube 18, and when the paper tube 18 is manufactured,
It is made by rolling one or two layers of aluminum foil into a single body. A ceramic fiber 16 whose inner diameter is 0.5 to 2.0 mm larger than the outer diameter of the paper tube 18 is set on the outer periphery of the inner paper tube 18, and a gap 21 of 0.5 to 2.0 mm is provided between it and the paper tube 18. It has a double pipe structure.

With this structure, water vapor, gas, etc. generated when the paper tube 18 is heated are blocked by the aluminum foil 19 and released to the outside through the gap 21, and are prevented from spouting into the inside of the paper tube 18. do not have.

However, in this case, since the paper tube 18 is in direct contact with the ceramic housing 14, if the immersion time is too long, the aluminum foil in that area will burn out and become ineffective, so the relatively short immersion into molten steel at 1600℃ Suitable for immersion for a short period of time.

Note that instead of the aluminum foil 19 of the paper tube 18, a layer of a suitable material that does not allow moisture or gas to pass through, such as moisture-proof cellophane or resin film, may be provided.

FIG. 10 is an explanatory diagram showing another embodiment of the consumable probe of the present invention. Regarding the housing of the probe tip in the embodiment shown in FIG. 9, a heat-resistant plastic housing 15 is installed behind the ceramic housing 14. It is characterized by having been established.

That is, instead of the ceramic housing in the conventional probe, a ceramic housing 14 is used.
A housing 15 made of heat-resistant plastic is provided between the sensor and the connector 17 at the rear end, and the housing structure of the sensor is such that the ceramic housing 14, the plastic housing 15, and the connector 17 are sequentially arranged from the tip. Here, the plastic housing 15 is 3 to 4 mm smaller in diameter than the ceramic housing 14,
A paper tube 18 is fitted and inserted into this small diameter portion. However, it is perfectly acceptable for the plastic housing 15 to have a larger diameter or the same diameter.

In addition, the use of aluminum foil 19 in the paper tube 18,
Alternatively, there is a gap 2 between the ceramic fiber 16 and the ceramic fiber 16.
1 is common to the embodiment shown in FIG.

With this structure, the generated water vapor, gas, etc. can be removed from the aluminum foil 19 as in the embodiment shown in FIG.
In addition to being blocked by and released to the outside from the gap 21,
Since the paper tube 18 is not in contact with the ceramic housing 14 but is in contact with the plastic housing 15, it is insulated from the tip of the probe.
8 is heated slowly and can be immersed in molten steel for a relatively long time compared to the embodiment shown in FIG.

FIG. 11 is an explanatory diagram showing an embodiment of the present invention regarding a composite probe that simultaneously measures temperature, carbon, and oxygen concentrations.

Generally, temperature and carbon concentration measurements using a composite probe require only a few seconds of immersion time, so a conventional composite probe that uses a paper tube as the protection tube may be used.
When an oxygen detector for measuring oxygen concentration, that is, an oxygen concentration battery is installed, the oxygen concentration measurement output fluctuates and accuracy decreases due to boiling of the molten steel due to water vapor and combustion gas ejected from the paper tube into the molten steel. , causing major problems such as poor instructions. In addition, it usually takes 10 to 20 seconds to measure oxygen concentration, and if a paper tube is used, the probe will burn out, so a fire-resistant protection tube is generally required, but this avoids molten steel boiling and contamination of the connector inside the probe. Therefore, a refractory material is required that does not emit water vapor, combustion gas, etc. when immersed in molten steel.

This problem with the composite probe is solved by providing a ceramic fiber 16 over the entire outer circumference of the body of the paper tube 18, as shown in the embodiment shown in FIG.

With such a structure, if it is possible to carry out measurements until the probe burns out, approximately 2
This makes it possible to immerse the probe for about 20 seconds, which satisfies the measurement conditions, even if problems such as poor measurement due to boiling or contamination within the probe are taken into consideration.

In this case, in order to strengthen the insulation of the paper tube 18 and prevent the generation of water vapor, combustion gas, etc., the ceramic fiber 16 needs to be sufficiently thick. Naturally, the greater the wall thickness, the better the insulation effect will be, but since the ceramic fiber 16 is expensive, this may affect the price of the probe and undermine the original purpose of the consumable probe. Therefore, it is necessary to make the ceramic fiber as thin as possible while still satisfying the required degree of insulation. For example, in order to create effective measurement conditions over a 20 second immersion time, a commercially available ceramic fiber is used with a thickness of 13 mm. The required thickness is difficult to determine because the insulation effect varies depending on the type of ceramic fiber, but if the insulation effect is high, it is possible to make it thinner.

Further, in consideration of cost issues, demands for miniaturization of the probe, etc., it is preferable to make the probe as thin as possible.

FIG. 12 shows another embodiment of the present invention in a composite probe, in which an aluminum foil 19 is provided in the inner surface layer of the paper tube 18 to further improve the heat insulation effect and the effect of preventing contamination inside the probe. In addition to blocking the ejection of combustion gas and the like into the probe, a ceramic fiber 16 with an inner diameter 0.5 to 2.0 mm larger than the outer diameter of the paper tube 18 is provided along the entire outer circumference, and the paper tube 18 and the ceramic fiber 16 are connected to each other. A gap 21 is formed between the two to allow ejected water vapor, combustion gas, etc. to be released to the outside.

FIG. 13 shows an embodiment of the present invention using ceramic fibers for a conventional consumable probe, the ceramic fibers 16 being provided along the entire length of the probe body on the outer periphery of the inner paper tube 18. As an example, by coating a commercially available ceramic fiber with a thickness of 13 mm, a measurable effective immersion time of 25 seconds was obtained. Since this embodiment has a simple structure, it can be said to be the most suitable for implementing the present invention.

Incidentally, although it is preferable to provide the ceramic fiber 16 along the entire length of the probe, since there is a problem in terms of cost as described above, the ceramic fiber 16 may be provided only at the tip of the probe. In this case, a paper tube is used behind the ceramic fiber at the tip, which inevitably reduces the immersion time, but the insulation effect at the tip and the effect of preventing boiling from affecting the measurement can be reliably obtained. The length of the ceramic fiber at the tip is preferably about 200 mm, but depending on the purpose of measurement, a length of 30 mm or 50 mm may be enough to obtain the effect of the consumable probe of the present invention.

FIG. 14 is an explanatory view showing an embodiment of the present invention which includes all the combinations of a heat insulating structure using ceramic fiber and a plastic housing, formation of an impermeable layer in a paper tube, and a double paper tube structure. This embodiment corresponds to the embodiment shown in FIG.
By providing an aluminum foil 19 in the inner surface layer of the inner paper tube 18 and using a paper tube 20 with an inner diameter 0.5 to 2.0 mm larger than the outer diameter of the paper tube 18, a double paper tube structure with a gap 21 is achieved. It is characterized by what it did.

Therefore, compared to the embodiment shown in FIG.
This has the effect of extending the measurement effective immersion time. Of course, the injection of water vapor and combustion gas into the probe can be completely prevented, and boiling that affects measurements does not occur.

As described above, the consumable probe of the present invention is a paper tube whose outer periphery is coated with ceramic fiber in order to obtain a heat insulating effect.Currently, a wide variety of ceramic fibers are manufactured and sold. . Although any of these materials can be effectively used in the consumable probe of the present invention, it is particularly preferable to use ceramic fibers that use an inorganic binder as the binder. This is because, with ceramic fibers that use organic binders, the binder decomposes during immersion in molten steel and is released as gas, causing boiling and, in some cases, leaking the paper tube. This is because there is a risk that the effect of the probe as a consumable probe may be impaired.

As explained above, with the consumable probe of the present invention, by suppressing the propagation of heat transmitted to the paper tube, it is possible to suppress the ejection of water vapor and combustion gas from the paper tube as much as possible. By blocking water vapor, combustion gas, etc. from entering the probe, even if water vapor or combustion gas is generated, it is possible to prevent poor measurements and decreases in accuracy due to contamination near the connector inside the probe, achieving an extremely high measurement success rate. Furthermore, since boiling of the molten steel does not occur due to the ejection of steam, gas, etc., the stability and accuracy of measurement can be maintained reliably, resulting in improved efficiency, improved quality, and reduced measurement costs in steelmaking operations. It was made.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the measurement state of a consumable probe in a converter; Figures 2, 3, 4, and 5 are explanatory diagrams showing an example of a conventional consumable probe set in a holder; The seventh explanatory diagram showing one embodiment of the consumable probe of the invention also shows the embedded position of a thermocouple for measuring the temperature inside the probe.
The figure is a graph showing the temperature change over time in the probe during immersion in molten steel in the embodiment shown in Figure 6. Figure 8 is a graph showing the temperature change over time in the conventional probe as shown in Figure 7.
9 and 10 are explanatory diagrams showing other embodiments of the consumable probe of the present invention.
Figures 1 and 12 are explanatory diagrams showing an embodiment of the consumable probe of the present invention used for converter sublance.
Fig. 3 is an explanatory diagram showing an embodiment of the consumable probe of the present invention in which ceramic fibers are provided along the entire length of the probe body, and Fig. 14 is an explanatory diagram showing an embodiment of the consumable probe of the present invention in which ceramic fibers are provided along the entire length of the probe body.
FIG. 2 is an explanatory view showing an embodiment of the consumable probe of the present invention, which combines a heat-resistant plastic housing and a double paper tube structure. 1...Probe, 2...Holder, 3...Converter, 4...
Molten steel, 5, 5'...Contact, 6...Socket, 7...Detector such as thermocouple, 8...Refractory (fireproof mortar land cement), 9...Ceramic, 10...Sensor inside, 11...Sensor, 12...NC processing Protective refractory for refractories, 13... NC processed refractory, 14... Ceramic housing, 15... Heat-resistant plastic housing (plastic housing), 16
...ceramic fiber, 17...connector,
18...Paper tube (inside), 19...Aluminum foil, 20...Paper tube (outside), 21...Gap, 22...Flowable self-hardening mold material or shell mold refractory.

Claims (1)

[Claims] 1. Sensor and holder and protecting them;
A consumable probe consisting of a paper tube whose outer circumferential surface is coated with ceramic fiber, the probe includes a sensor,
A consumable probe characterized in that a ceramic housing, a plastic housing, and a connector are sequentially arranged, and the plastic housing and the paper tube are connected and arranged. 2. In a consumable probe consisting of a paper tube with a sensor, a holder, and a ceramic fiber coated on the outer circumferential surface to protect them, the sensor, the sensor,
A ceramic housing and a connector are arranged in sequence, and a moisture and gas impermeable material layer is integrally formed in the inner surface layer of the paper tube, and a gap is created between the paper tube and the coated ceramic fiber. established,
A consumable probe characterized in that the plastic housing and the paper tube are connected and arranged. 3. The consumable probe according to claim 2, characterized in that the probe has a sensor, a ceramic housing, and a plastic housing arranged in this order from its tip. 4. A material layer according to claim 2, characterized in that a material layer selected from aluminum foil, moisture-proof cellophane, resin film, etc. is used as the material layer that is integrally formed with the paper tube and is impermeable to moisture and gas. Expendable probe.