JPS63176413A - Thermocouple probe for measuring temperature of molten steel - Google Patents

Abstract

PURPOSE:To reduce wear of supporting rods of a thermocouple probe for measuring temp. of molten steel by coating thermocouple chips projected from the top end of said probe with refractories having excellent refractoriness and electrical insulating characteristic and exposing thermocouple strands therefrom. CONSTITUTION:The supporting rod 10 of the thermocouple probe which measures the temp. of a high-temp. molten metal such as molten steel is constituted of a shielding pipe 24 formed to a cylindrical shape by winding paper and a protective pipe 26 made of a refractory material such as alumina. The thermocouple strands 13, 14 are inserted into the supporting bodies 12, 12 made of the refractories embedded into a packing material 31 such as Hishiko cement and the top ends 13a, 14a thereof are exposed from the bodies 12. This probe is immersed into the molten steel at the time of measuring the temp. of the molten steel, by which the exposed ends 13a, 14a of the strands 13, 14 are short- circuited to form a thermocouple. The temp. of the molten steel is thus extremely quickly measured and the wear of the supporting rods is reduced and the rods are usable many times.

Description

[Detailed description of the invention] The present invention aims to solve the following problems.

(Industrial Application Field) This invention applies to the temperature of molten steel (in this specification, not only molten steel but also molten metal of other metals are referred to as molten steel) in melting and refining work of steel and other metals. This article relates to thermocouple probes used to measure .

(Prior Art) A conventional thermocouple probe for temperature measurement of molten steel has a structure as shown in FIG. That is,
A thermocouple chip 11f is provided at the tip of the support rod 10f, and wires 12f, 13f are provided inside a silica tube 15f with an air gap 40 in between at the exposed portion 11af of the tip Ilf. In such a device, when the tip of the support rod is inserted into the molten steel to measure the temperature of the molten steel, the heat of the molten steel is transmitted to the strands 12f and 13f via the silica tube 15f and the finished tube 40. , its temperature increases.

In this case, the air gap 40 has extremely poor heat transfer (,
It takes an extremely long time (for example, 5 to 10 seconds) for the temperature of the wires 12f and 13f to rise to a temperature corresponding to the temperature of the molten steel and become stable. Therefore, during the temperature measurement, the support rod 1
0f is consumed. As a result, one probe
Use only for temperature measurements.

There was a problem that it could not be done.

(Problems to be Solved by the Invention) This invention eliminates the above-mentioned conventional problems and dramatically increases the service life by extremely reducing wear and tear on the support rod per temperature measurement unit. The object of the present invention is to provide a thermocouple probe for measuring temperature of molten steel.

The configuration of the present invention is as follows.

(Means for Solving the Problems) The present invention takes the measures as described in the claims above, and its effects are as follows.

(Function) When the exposed part of the thermocouple tip is inserted into molten steel, each tip of the two thermocouple wires at the tip? 8. Direct contact with steel. Then, the pixel lines are electrically connected by the molten steel, and at the same time, each tip of the pixel line immediately becomes hot due to the heat of the molten steel, and a thermoelectromotive force corresponding to the temperature of the molten steel is generated between the bases of each element wire in the support rod. It will be done.

(Embodiments) The drawings showing the embodiments of the present application will be explained below. In FIG. 1, l indicates a smelting furnace.

In this figure, 3 represents the furnace body, and 4 represents the furnace lid.

The furnace body 3 is formed in a concave shape, and is provided with a furnace port 17 at the top and a tuyere 18 for blowing refining gas at the bottom. 19 indicates molten steel. Next, the furnace lid 4 has an exhaust port 2.
0 and an insertion opening 22 for a thermocouple probe.
Reference numeral 21 indicates a well-known dust collection hood facing the exhaust port 20.

Next, 2 is 7i! ! The temperature measuring device 2 shown in FIG. 1 includes a temperature measuring section 5 and a display section 6. In the temperature measuring section 5, 7 is a lifting device, which is configured so that the holder 8 attached to the temperature measuring section 5 can be raised immediately after being lowered.

In the zero-order display section 6, 9 indicates a thermocouple probe attached to the lower end of the holder 8, 33 a thermoelectromotive force detector,
Reference numeral 35 indicates a maximum temperature indicator.

Next, in the thermocouple probe 9, 1o is a support rod,
The structure is such that the interior can be thermally shielded with a structure that will be described in detail later. 10a indicates the tip of the support rod;
A thermocouple chip 11 is provided there.

Next, FIG. 2, which shows in detail the structure related to the support rod 10 and the thermocouple chip 11, will be described. In the support rod 10, 24 is a shielding tube, which is formed into a cylindrical shape (for example, an aspal pipe) using a cylindrical material, and has a length of, for example, 1 m1.
The thickness is about 30m. Reference numeral 25 indicates a temperature measuring element attached to the shielding tube 24, in which 26 is a protection tube made of a heat-resistant material such as alumina. Reference numeral 27 indicates a connector attached to the protection tube 26. This connector 27 connects with a known corresponding connector provided on the holder 8. In the above connection tool 27, 28 is a supporter made of an insulating material.
Reference numerals 29 and 30 indicate compensation conductor wires attached to the supporter 28, and are made of, for example, copper wire. Reference numeral 31 denotes a filler filled in the protective tube 26 for fixing the thermocouple tube 11, and is made of, for example, HYSICON cement.

Next, in the thermocouple chip 11, lla is a portion exposed from the tip 10b of the support rod 1o, and llb is a portion built into the support rod 10, which is fixed by the filler 31. Reference numeral 12.12 denotes a support supported by the filler 3I, which is made of a hard material with good fire resistance and electrical insulation, such as silica or alumina. Further, regarding their dimensions, the thickness is, for example, 2 dragons φ, and the protrusion length from the tip 10b is, for example, 30 m.

Reference numerals 13 and 14 indicate thermocouple wires inserted through each of the supports 12 and 12, for example, thin wires (for example, 0.2 mmφ) of platinum and platinum-rhodium alloy are used, respectively. These pixel lines 13°1
4 are exposed at the end face of the support 12, and the bases are connected to compensation conductors 29 and 30, respectively. The thermocouple chip 11 as described above is manufactured by surrounding each strand 13, 14 with the support 12 as described above.

When measuring the temperature of the molten steel 19 in the refining furnace 1 with the above configuration, the holder 8 is first lowered by the lifting device 7. As a result, in the thermocouple probe 9, the thermocouple tip 11 and the tip 10a of the support rod 10 are exposed to the molten steel 19.
inserted within. The insertion depth (temperature measurement level) is, for example, 200 to 600 mm. When the insertion is performed as described above, in the exposed portion 11a of the thermocouple chip 11, the thermocouple wires 13 and 14 exposed at the tip of each support 12 are
The tips of each are electrically connected to each other by the molten steel 19. At the same time, the heat of the melt f419 is transferred to the tips of each strand 13, 14, and they instantly rise to a temperature corresponding to one temperature of the melt f419. As a result, a thermoelectromotive force corresponding to the temperature of the tip of the wire is obtained at the points 29a and 30a of the compensating lead wire 29, 30, which are connected to the connector on the holder 8 side. The thermoelectromotive force is transmitted from the connector on the holder 8 side to the thermoelectromotive force detector 33 via the lead wire 33a, and the thermoelectromotive force is measured. Based on the value measured by the detector 33, the maximum temperature indicator 35 displays the temperature of the molten steel.

Immediately thereafter, the lifting device 7 raises the holder 8, and the thermocouple probe 9 is lifted out of the molten steel 19.

Next, the generation of thermoelectromotive force in the above case will be explained based on FIGS. 4 and 5. As described above, the exposed portion 11a of the thermocouple chip 11 is at a temperature T. When immersed in the molten steel 19 at .degree. C., minute alloy layers 13a, 14a are formed at the tips of each wire 13, 14 due to contact with the molten steel 19.

However, since they are extremely small, P4. P3.
P5. The temperatures at each point indicated by P6 are all TH°C.

Therefore, as shown in FIG. 5, no thermoelectromotive force is generated between points 23 and 26, while point P2. The temperature at P7 becomes T c '''C, and also at point PI.

The temperature of P8 becomes Tc'C. Therefore, the wires 13 and 14 each generate a thermoelectromotive force corresponding to the temperature difference between TH and Tc', and the compensating conductors 29 and 30 each generate a thermoelectromotive force corresponding to the temperature difference between Tc'' and Tc. As a result, point PI
, thermoelectromotive force △ corresponding to the temperature TH of the molten steel between P8
E is obtained.

When the above operation is performed, the tip 1 of the support rod 10
Since the time that the exposed portion 11a of the thermocouple tip 11 and the exposed portion 11a of the thermocouple tip 11 are immersed in the molten w419 is extremely short, there is very little wear and tear on the shielding tube 24 in the support rod 10 and on the tip end of the tip during that time.

Furthermore, since the time required to detect the temperature of molten steel as described above is extremely short, e.g. 0.5 seconds or less,
The true temperature of the molten steel (i.e., the highest detected temperature) can be determined within the mechanical time required to simply immerse and pull up the probe. Therefore, a complicated calculation circuit (
For example, calculation of temperature change rate, etc.) is not necessary, and it is also effective in reducing equipment costs.

Next, FIG. 6 shows another embodiment of the present application, and shows an example in which two thermocouple wires 13el and 14e are inserted into one support member 12e protruding from the tip of the support rod 10e. be.

It should be noted that parts that are considered to have the same or equivalent structure as those in the previous figure in terms of function are given the same reference numerals as in the previous figure with the letter e, and redundant explanations are omitted.

(Effects of the Invention) As described above, what does the present invention have? 8
When it is desired to measure the temperature of fi19, when the exposed portion 11a of the thermocouple tip 11 is inserted into the molten steel 19, each tip of each thermocouple wire 13 and 14 in the tip 11 comes into direct contact with the molten steel.
When the pixel lines 13 and 14 are electrically connected to each other by the molten steel, each tip of the pixel lines 13 and 14 immediately becomes hot due to the heat of the molten steel. As a result, a thermoelectromotive force corresponding to the temperature of the molten steel can be obtained in the part of the tip 11 built into the support rod 10, and the temperature of the molten steel can be calculated by measuring the electromotive force. be.

Moreover, in the above case, as mentioned above, each tip of each wire 13, 14 in the tip 11 has the advantage of being brought into direct contact with the molten steel and immediately heated to the temperature of the molten steel. This means that immersing the tip 11 into the molten steel 19 for temperature measurement can be done instantaneously, and even if the support rod 10 is inserted into the T8 steel 19 and then immediately pulled up, accurate temperature measurement is possible. Can be done. As a result, the wear and tear of the support rod 10 due to the high heat of molten steel per temperature measurement can be significantly reduced, and there is an advantage that the number of service times can be dramatically increased compared to conventional products.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIG. 1 is a diagram schematically showing a temperature measurement situation in a scouring furnace, and FIG. 2 is a partial cross-sectional view showing the relationship between a support rod and a thermocouple tip in a thermocouple probe. Third
The figure is an enlarged cross-sectional view of the section cut along the ■-■ line, Figure 4 is a diagram explaining the temperature state of each part when the thermocouple tip is immersed in '/B steel, and Figure 5 is a diagram explaining the temperature state of each part in the case of Figure 4. FIG. 6 is a partially cutaway view showing another embodiment, and FIG. 7 is a partially sectional view showing a conventional thermocouple probe. lO...Support rod, 11...Thermocouple chip, 12...
-Support, 13.14... elemental wire. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] At the tip of the support rod, which is immersed in the molten steel, there is a thermocouple chip, a part of which is exposed from the tip of the support rod, and the base is built into the support rod and is thermally shielded by the support rod. In the thermocouple probe for measuring the temperature of molten steel, the part of the thermocouple tip exposed from the tip of the support rod is made of a fire-resistant and electrically insulating material that protrudes from the tip of the support rod. In the support formed,
1. A thermocouple probe for temperature measurement of molten steel, characterized in that two thermocouple wires are inserted through the wires, and each tip of the thermocouple wires is exposed at the tip of the support.