JPH044215Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention is applicable to measuring elements of molten metal measurement probes (e.g., temperature detection elements, oxygen concentration batteries for measuring the amount of oxygen, and other components for measuring components in molten metals). This relates to a measuring element protector that protects the measuring element (elements, etc.).

(Background of the idea) In order to adjust the blow-off temperature and blow-off components in a refining furnace, such as a computer-controlled converter, it is necessary to provide control information such as temperature and components (mainly carbon content and oxygen content) at least during blowing. It is essential to know at any point in time (usually between 0 and 2 minutes before blow-off).

Conventionally, as shown in FIG. 6, a measuring probe 11 is attached to a sublance 9 and immersed in the molten metal 3 in order to measure the temperature, carbon content, oxygen content, etc. of the molten metal 3 in the converter 1 during blowing. The method is widely used.

In this case, as shown in Fig. 7a (for temperature detection) or Fig. 7b (for oxygen content measurement), the measuring element 14 at the lower end of the measuring probe 11 is protected by a metal cap 15 and melts after passing through the slag layer 2. When it reaches the metal 3, the cap 15 melts and the measuring element 1
4 will be exposed and the intended measurement will be performed.

However, molten metal 3 such as molten pig iron and scrap are charged into the converter 1, and if the scrap content ratio is high, damage to the measuring element 14 may occur due to the following reasons, and the converter may be damaged. There is a greater possibility that the temperature cannot be measured during blowing in the furnace 1: A. Physical damage (damage due to hard slag) If the scrap content is high, the slag formation into slag will be delayed and no reaction will occur when measured by the temperature probe 11. A large amount of lime or quicklime remains in the slag layer 2 to form a hard slag, and the cap 15 and the measuring element 14 collide with this and are damaged.

B Physical damage (damage due to undissolved scrap lumps) Due to the high scrap content ratio, the scrap is not completely dissolved during measurement during refining using an automatic insertion device such as Sublance 9, and such undissolved scrap The measuring element 14 exposed in the molten metal 3 collides with the lump 5 and is damaged.

C Physical damage (damage due to flowing low-temperature slag, granulated iron, etc.) Hard low-temperature slag that has delayed slag formation due to the high scrap content and granulated iron present in large quantities in the slag layer 2 may cause damage to the main lance 7. It flows due to the stirring of the oxygen jet 8, collides with or comes into contact with the measuring element 14, and physically damages the measuring element 14.

D. Scientific erosion The slag adheres to the measuring element 14 and causes a chemical reaction, which destroys the elements (for example, SiO ₂ tube, Pt thermocouple wire, etc.) that constitute the element.

None of these examples poses a major problem in the case of a static bath after blowing, but when measuring during blowing, as mentioned above, the oxygen jet 8 of the main lance 7
The occurrence of these problems is further exacerbated by the agitation caused by this.

According to experience, the success rate of temperature measurement during blowing is usually more than 95% under conditions of scrap content of 0 to 15%, but when the scrap content is higher than this and the slag formation conditions are not good. , the temperature measurement success rate drops significantly to 60-90%.

For example, when the scrap rate is 25%, the measurement temperature is around 1540℃, and the carbon content is around 0.60%, the normal temperature success rate is 90%.
It is difficult to obtain more than that.

It is known that the higher the scrap content ratio, the higher the defect rate measured during blowing.

(Disclosure of publicly known documents, etc.) In order to prevent temperature detection elements and other component detection elements from being damaged during immersion due to hardened slag, conventional methods have been used such as Utility Model Publication No. 52-52625, Utility Model Application Publication No. 58-154461,
Utility Model Application Publication No. 58-178668 is publicly known.

(Purpose of the invention) The present invention improves the conventional method described above, and provides a method for molten metal that can more fully protect the metering element from damage even when unmelted scrap lumps or hard slag are present during blowing. The purpose is to provide a measuring element protector for a measuring probe.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The protector of the present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 shows the protector of the present invention together with a measuring probe equipped with a measuring element, such as a temperature detecting element, and the measuring probe 11 has a support 19 made of ceramics or the like forming the lower end surface of the main body 12.

The support body 19 supports the measuring element 14 that projects downward.

The measuring element 14 is covered with a metal cap 15, and the cap 15 is covered with a cover 22.

The cover 22 is made of a material, such as metal, ceramics, cardboard, wood chips, etc., that has sufficient strength to protect the measuring element 14 from damage caused by the aforementioned factors, and that can withstand mechanical and thermal shock while passing through the slag layer 2. .

Further, the cover 22 is joined to the lower end surface of the main body 12 (in the embodiment, an adhesive 23 is used).

Next, in the space between the cap 15 and the cover 22, a gas generating substance 25 which reacts and generates gas when energized, heated, etc. is sealed.

Although the gas generating substance 25 is not particularly limited,
For example, there are materials with N-O bonds, N-N bonds, O-O bonds, O-halogen bonds, etc. that are known as explosive substances, and in some cases, heat-generating materials. used with

Further, as the gas generating substance 25, it is also possible to use explosives such as gunpowder whose explosive expansion power is adjusted.

The gas generated at this time may be of any type as long as it can provide enough pressure to separate the cover 22 from the main body 12.

Various methods can be considered for causing the gas generating substance 25 to react.

One method is to connect a lead wire 21 equipped with a heater to the gas generating substance 25 so that it can be heated with electricity at any time to generate gas.

Usually, the gas generation timing is determined based on a signal when the automatic insertion device such as the sub-lance 9 stops descending or a signal when it reaches a predetermined position.

As another method, as shown in FIGS. 2 and 3, for example, 0.2 to 0.2
A gap 26 of about 2.0 mm is left open, and when the measurement probe 11 is immersed in the molten metal 3, the molten metal 3 enters through this gap 26 and the gas generating substance 25
There is a method of generating gas by contacting the molten metal 3 (in this case, it is necessary to take into account the difference in viscosity and surface tension between the slag and the molten metal 3 in order to prevent the slag from flowing in through the gap 26).

In addition, as a method other than this, as shown in FIG.
By placing one end in contact with the gas generating substance 25 and the other end near the outer peripheral surface of the measurement probe 11,
It is also possible to transfer the heat of the molten metal 3 to the gas generating substance 25 and cause it to react (in this case, it is desirable to provide a heat insulating cover or the like so as not to be affected by the heat when passing through the slag layer 2).

Further, as another protective member of the present invention, a cover 22 may be brought into close contact with the lower end surface of the main body 12 as shown in FIG. 5, and the cap 15 may be omitted.

The action of the protector of the present invention shown in the above embodiments is as follows.

That is, as shown in FIG. 6, a measuring probe 11 is attached to an automatic insertion device such as a sublance 9, and the measuring probe 11 is lowered into the converter 1 during blowing.

As a result, the protector at the lower end of the measurement probe 11 first passes through the slag layer 2, then the mixed layer of slag and molten metal 3, and then the molten metal 3, and stops at a predetermined position in the molten metal 3.

When passing through the slag layer 2 and the mixed layer of slag and molten metal 3, the measuring element 14 is protected by a protective cover 22.

Furthermore, since the protective body remains temporarily attached even after being immersed in the molten metal 3, the measurement element 14 is prevented from coming into contact with floating solid matter such as undissolved scrap mass 5 in the initial stage.

Next, when the protector reaches the measuring point in the molten metal 3, the gas generating substance 25 reacts due to electricity supply, temperature rise, etc. and generates gas.

This increases the pressure within the cover 22 and separates the cover 22 from the lower end surface of the main body 12.

Further, since convection of the molten metal 3 exists, if even a part of the cover 22 is released, the cover 22 can be separated from that part.

The separation of the cover 22 brings the cap 15, if present, into contact with the molten metal 3;
Dissolves immediately.

As a result, the measurement element 14 is exposed in the molten metal 3 and starts measurement.

The protector of the present invention may have the following configuration other than that shown in the above embodiments.

In other words, the measurement element 14 is a concept in a broad sense, and for example, when a sample introduction tube (not shown) is arranged on the lower end surface of the main body 12 of the measurement probe 11 to collect a sample of molten metal, the measurement element 14 can also be used for measurement. It shall be interpreted as element 14.

(Effects of the Invention) The measuring element protector of the molten metal measuring probe of the present invention has the following effects in the configuration and operation shown in the above embodiments.

(1) The protector of the present invention has the structure described in the claims for utility model registration, and in particular, the measuring element is covered with a cover made of a material that can withstand mechanical and thermal shock while passing through the slag layer. During immersion, it is sufficiently protected from hard slag, low-temperature slag, granulated iron, and undissolved scrap lumps, and there is no risk of damage from these.

(2) The protector of the present invention has the same structure as above, and in particular, since the gas generating substance is enclosed within the cover,
Gas is generated in the molten metal and the pressure within the cover increases to ensure that the cover is separated.

[Brief explanation of the drawing]

Fig. 1 is a sectional front view showing the protector of the present invention together with a measurement probe, Fig. 2 is a sectional front view showing another protector similar to the above, Fig. 3 is a cross-sectional view of Fig. 2, and Fig. 4 is a sectional front view showing the protector of the present invention together with a measurement probe.
The figure is a cross-sectional front view showing another protector of the present invention.
FIG. 6 is a conceptual diagram showing a conventional measuring probe for public use; FIG. 7a and FIG. 7b are cross-sectional front views of the cap of a conventional measuring probe. 1... Converter, 2... Slag layer, 3... Molten metal, 5... Unmelted scrap lump, 7... Main lance, 8... Oxygen jet, 9... Sublance,
11...Measuring probe, 12...Main body, 14...
Measuring element, 15...cap, 19...support,
21... Lead wire, 22... Cover, 23... Adhesive, 25... Gas generating substance, 26... Gap, 2
7...Thermal conductive material.

Claims (1)

[Scope of utility model registration request] The measuring element that protrudes downward on the lower end surface of the measuring probe body is coated to prevent mechanical damage while passing through the slag layer.
A measuring element protector for a molten metal measuring probe, comprising a cover made of a material that can withstand thermal shock and bonded to the lower end surface, and a gas generating substance that is sealed within the cover and generates gas when energized, heated, etc.