JPS6224847A - Method and instrument for measuring air permeability of gas blow-off type nozzle for pouring molten metal - Google Patents

Abstract

PURPOSE:To exactly detect the rate of air permeability of a gas blow-off type nozzle for pouring a molten metal in the prescribed range in the axial direction of the inside wall of the nozzle hole by hermetically sealing the required range of the inside wall of the above-mentioned nozzle with upper and lower partition walls, leading out the blowing gas from the inside wall surface and measuring the flow rate thereof. CONSTITUTION:The required range of the inside hole 3 of the gas blow-off type nozzle 1 for pouring the molten metal is sealed by the pressurization 23 of a sealing tube 15 of upper and lower partition plates 12 connected by a length-adjustable connecting pipe member 17 to constitute a hermetic chamber. The gas blown to the pressurized inside wall of a gas filled chamber 2 is led out by a gas lead-out pipe 19 of a lead-out hole 18 and the flow rate thereof is measured by a probe 22 of a measuring instrument 21. The rate of air permeability in the prescribed range on the inside wall of the nozzle hole 3 is exactly detected by adjusting the length of the member 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for measuring the air flow rate of a gas blowing type molten metal injection nozzle.

[Conventional technology]

A gas blowing type molten metal injection nozzle injects molten metal from a ladle or tundish into continuous casting equipment.
In order to prevent non-metallic inclusions from adhering to the inner wall of the nozzle hole, especially near the discharge port that is immersed in molten metal on the equipment side, a cylindrical nozzle body 1 made of refractory material is used as shown in FIG. A circular gas chamber 2 is provided concentrically with the nozzle hole 3, and is oval shaped so that the compressed gas such as N2 gas filled in the gas chamber 2 is blown out from the inner wall of the nozzle hole.

The amount of gas blown out from the inner wall of the nozzle hole in the above-mentioned gas blowing type molten metal injection nozzle is usually measured in advance before mounting it on the tundish. A plug (
(not shown) and a flow meter 8 such as a flow meter interposed between the plug and the regulator 5 in the conduit 7 is used.

In addition, in FIG. 3, 9 is a corrosion-resistant part provided on the outer periphery of the nozzle body to prevent local erosion caused by mold powder, 3a is a discharge port of the nozzle hole 3, and 10.11 is a pipe line on both sides of the flowmeter 8. This is a pressure gauge installed at 7.

[Problem that the invention seeks to solve]

However, when using the above conventional measurement method, there is gas leakage from the joint between the nozzle body 1 and the gas introduction socket 4, which are fixed with an inorganic adhesive, and the gas filled in the gas filling chamber 2. Since the gas is also blown out from the outer circumferential wall of the nozzle body 1, it is difficult to accurately measure the amount of gas blown out from the inner wall of the nozzle hole.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a method for measuring the amount of gas blown out from the inner wall of a nozzle hole in a gas blowing type molten metal injection nozzle made of a refractory material, the method comprising: airtightly partition a required range extending in the radial direction by a pair of partition walls extending in the radial direction, and direct the gas blown from the inner wall of the nozzle hole into the space surrounded by the both corner walls and the inner wall of the nozzle hole from one partition wall. This method measures the amount of gas blown out from the inner wall of the nozzle hole in a required range in the axial direction within the nozzle hole.

Further, a second invention is a device for measuring the amount of gas blown out from an inner wall of a nozzle hole in a gas blowing type molten metal injection nozzle made of a refractory material, for use in carrying out the specified invention, the device comprising: an inner diameter of the nozzle hole; A pair of partition disks with a suitably smaller diameter are connected parallel to each other at a required interval, a seal tube that is inflated by compressed air is fitted around the outer periphery of each partition disk, and gas is injected into one of the partition disks. It is constructed by attaching a lead-off pipe and a measuring device to measure the amount of the led-out gas to the gas lead-out pipe, and placing a pair of partition discs at the required position in the nozzle hole of the blow-out type molten metal injection nozzle. After inserting compressed air into the seal tube provided on each partition disc to airtightly partition the required range in the axial direction inside the nozzle hole, a compressed gas such as N2 gas or air is introduced from the gas introduction socket. The gas introduced into the plenum chamber, passed through the nozzle body, and blown out from the inner wall of the nozzle hole into the partitioned space is led out by a gas outlet pipe, and the amount of the led out gas is measured by a measuring instrument.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In the following description, the same members and the like as in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, a pair of partition disks 12 that constitute a part of the airflow rate measuring device according to the present invention are formed in a disk shape with a suitably smaller diameter than the inner diameter of the nozzle hole 3. A ventilation groove 13 is formed around the entire circumference of each partition disk 12, and a radial direction (
A ventilation hole 14 is opened in the left-right direction in FIGS. 1 and 2. Further, a seal tube 15 having a U-shaped cross section and made of elastic rubber or the like is fitted into the outer periphery of each partition disk 12, and is airtightly attached by a ring-shaped holding fitting 16. The pair of partition disks 12 are connected to each other by a plurality of connecting members 17 that are longer than the length in the axial direction (vertical direction in FIGS. 1 and 2) of the gas filling chamber 2 of the gas blowing type molten metal injection nozzle. They are connected in parallel, and one of the connecting members 17 is connected to the ventilation hole 14 of each partition disk 12.
They are provided in a hollow shape to connect them.

At the center of one (upper part in FIG. 1) of the partition disk 12, there is provided an outlet hole 18 for introducing gas as described later, and the gas extracted from this outlet hole 18 is used for gas blowing type molten metal injection. The proximal end of a gas discharge pipe 19 which is discharged to the outside of the nozzle is airtightly attached to the outer surface of one of the partition disks 12 (the upper surface at 0 in FIG. 1). A probe insertion port 20 is provided at the tip side of the gas derivation pipe 19, and a probe 22 of a measuring device 21 such as a flow meter or anemometer for measuring the amount of gas to be discharged is inserted into the probe insertion port 20. is inserted. Further, the base end of a compressed air introduction pipe 23 for introducing compressed air into the seal tube 15 is airtightly inserted into one of the partition discs 12 and connected to the ventilation hole 14. The tip of the air introduction pipe 23 is connected to an air pressure source (not shown) such as a compressor.

Next, in order to measure the amount of gas blown out from the inner wall of the nozzle hole in the gas blowing type molten metal injection nozzle using the ventilation amount measuring device, first, the pair of partition disks 12 are connected to the gas blowing type molten metal injection nozzle. is inserted into the nozzle hole 3 of the molten metal injection nozzle, and positioned so that the gas-filled chamber 2 of the gas blowing type molten metal injection nozzle exists between both partition discs 12. Next, compressed air of 1.5 to 2.0 kg/ad is supplied from the air pressure source to each seal tube 1 through the compressed air introduction pipe 23, the ventilation hole 14, etc.
5, and each seal tube 15 is expanded and pressed against the inner wall of the nozzle hole.

After airtightly partitioning the axial range of the nozzle hole 3 facing the gas filling chamber 2 as described above, compressed gas such as N2 gas or air is introduced into the gas filling chamber 2 from the gas introduction socket 4. Then, this gas passes through the nozzle body 1 and is blown out from the inner wall of the nozzle hole.

The gas blown from the inner wall of the nozzle hole into the space partitioned by both partition disks 12 and the inner wall of the nozzle hole is passed from the outlet hole 18 of one partition disk 12 through the gas outlet pipe 19 to the gas blowing type molten metal injection nozzle. When the amount of the guided gas passing through the outlet pipe 19 is measured by the measuring device 21, the measurement of the amount of gas blown out from the inner wall of the nozzle hole in the gas blowing type molten metal injection nozzle is completed.

The table below shows the results of measuring the amount of ventilation according to the above-mentioned embodiment and the results of measuring the amount of ventilation according to the conventional technique.

In measurement example 1, the outer peripheral wall of the gas blowing type molten metal injection nozzle is dense, so the measurement results are almost the same, but in measurement example 2 and 2, gas leakage is observed in the inorganic adhesive that fixes the gas introduction socket to the nozzle body. In Measurement Example 3, the measurement results had errors of about 57% and about 21%.

In addition, in the embodiment described above, the pair of partition discs 12
A case will be described in which the amount of gas blown out from the inner wall of the nozzle hole facing the gas filling chamber 2 is measured using a device in which the two are connected by a connecting member 17 having a length approximately equal to the axial length of the gas filling chamber 2. However, the present invention is not limited to this, and for example, the pair of partition discs 12 may be separated by 1 part of the axial length of the gas-filled chamber 2.
A device connected by a connecting member 17 having a length of 72 to 1/6 or a connecting member 17 equipped with a telescoping mechanism is used.

The amount of gas blown out from a specific range in the axial direction of the inner wall of the nozzle hole facing the gas filling chamber 2 may be measured. It is possible to compare the amount of gas released.

In addition, one of the partition disks 12 is movably fitted to the connecting member 17 while maintaining airtightness, and the seal tubes 15 provided on each partition disk 12 are connected with flexible pipes such as vinyl pipes. However, the interval between both partition discs 12 may be arbitrarily adjusted.

〔Effect of the invention〕

As described above, according to the present invention, compared to the prior art, it is possible to accurately measure the amount of gas blown out from the inner wall of the nozzle hole, and the amount of gas blown out from the inner wall of the nozzle hole facing the gas filling chamber can be measured in the axial direction. It is also possible to accurately measure the amount of ventilation over a required range.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are a longitudinal cross-sectional view and an enlarged cross-sectional view of essential parts, respectively, showing how the air permeability measuring device according to the present invention is used;
FIG. 3 is an explanatory diagram of the prior art. 1... Nozzle body 2... Gas filling chamber 3...
Nozzle hole 4...Gas introduction socket 12...
Partition disk 14...Vent hole 15...Seal tube 17...Connection member 18...Outlet hole 19...
・Gas outlet pipe 20... Probe insertion port 21...
・Measuring equipment 22... Probe 23... Compressed air introduction pipe Applicant: Toshiba Ceramics Corporation Figure 1

Claims (2)

[Claims] (1) A method for measuring the amount of gas blown out from the inner wall of a nozzle hole in a gas blowing type molten metal injection nozzle made of a refractory material, the method comprising measuring a required range in the axial direction within the nozzle hole in the radial direction. Airtightly partitioned by a pair of partition walls,
A gas blowing type molten metal injection nozzle, characterized in that the gas blown out from the inner wall of the nozzle hole into a space surrounded by the two partition walls and the inner wall of the nozzle hole is led out from one partition wall, and the amount of the drawn gas is measured. How to measure airflow. (2) A device for measuring the amount of gas blown out from the inner wall of a nozzle hole in a gas blowing type molten metal injection nozzle made of refractory material, wherein a pair of partition disks having a diameter suitably smaller than the inner diameter of the nozzle hole are connected to A seal tube inflated by compressed air is fitted onto the outer periphery of each of the partition disks, a gas outlet pipe is attached to one of the partition disks, and the gas outlet pipe is connected to the partition disks in parallel with each other at intervals. 1. A ventilation amount measuring device for a gas blowing type molten metal injection nozzle, characterized in that it is configured by being equipped with a measuring device for measuring the amount of molten metal injection nozzle.