JPS6313883Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a microwave level meter for measuring the level of molten steel in a belt-drum continuous casting machine.

The belt/drum type continuous casting machine is shown in Figures 1 and 2.
As shown in the figure, an endless belt 5 is stretched by belt holding rollers 2, 3 and a belt tensioning roller 4 over a part of a rotating drum 1 as a mold, which is provided with flanges 1a as mold short pieces on both sides.
are brought into contact with each other to form a mold space A with the rotating drum 1 and the belt 5, and while rotating the rotating drum 1 and the belt 5 in the direction of arrow B, the molten steel from the tundish 6 is poured from the nozzle 7 into the mold space A. The slab 8 is poured into a mold and cooled in the mold space A, and then rolled by pinch rollers 9 and 10 and wound into a coil 11.

In this continuous casting machine, it is necessary to pay attention to the management of the molten steel level surface C in the mold space A, and for this reason, conventionally, a radiation method has been used to measure the level. In this method, the radiation source and the radiation receiver are arranged to face each other, and the received level of radiation changes depending on the fluctuation of the molten steel level surface C. Continuous measurement requires the installation of multiple pairs of radiation sources and radiation receivers, which is expensive, and it is also necessary to consider the effects on the human body when dealing with radiation. However, it was inconvenient to handle.

The present invention was developed in view of the above, and its purpose is to provide a microwave level meter that can continuously and safely measure the level of molten steel using microwaves. That's true.

Examples of the present invention will be described below. Third
The figure and FIG. 4 show one embodiment, and the same parts as in FIGS. 1 and 2 are given the same reference numerals. Reference numeral 12 denotes a microwave transmitter/receiver, from which a microwave waveguide 13 passes between the side of the nozzle 7 and the belt holding roller 2 on which the belt 5 is stretched, and its tip faces near the tip of the nozzle 7. is curved and elongated. Note that the tip of this waveguide 13 is set to be above the level surface where the molten steel level surface C is managed.
This waveguide 13 was bent because the waveguide 13 was bent.
This is because it is necessary to pass through the upper space between the belt 5 and the nozzle 7 so that the belt 5 and the drum 1 face the mold parallel space. 14 is molten steel in the tundish, and 15 is molten steel in the nozzle.

In this way, the microwave emitted from the microwave transceiver 12 enters the mold space A through the waveguide 13, and is subjected to multiple reflections by the rotating drum 1 and the belt 5, that is, by the inner wall of the mold space A. It repeats this until it reaches the molten steel level surface C, where it is reflected and returns to the microwave transmitter/receiver 12 via a similar path.

Therefore, by comparing the phase of the received microwave with that of the transmitted microwave in the microwave transmitter/receiver 12, it is possible to continuously measure fluctuations in the molten steel level surface C based on the time required for the microwave to travel back and forth. In this case, half of the detected phase difference directly has information on the molten steel level surface C. For example, if a microwave with a frequency of 1 GHz is used, its wavelength is 30 cm, so if the phase difference between the transmitted microwave and the received microwave changes by 360 degrees, it will be detected that the molten steel level surface C has changed by 15 cm. . As mentioned above, the microwave is repeatedly reflected multiple times by the rotating drum 1 and the belt 5 between the waveguide 13 and the molten steel level surface C, but since the state of this multiple reflection can be known in advance, By calibrating, accurate molten steel level surface values and variations can be measured.

Since one waveguide 13 is used for reciprocating microwaves, it is necessary to separate and extract the received microwave from the waveguide 13 using a circulator or directional coupler on the side of the microwave transmitter/receiver 12. In this case, the received microwave is attenuated, and is further attenuated because it is separated by a circulator or directional coupler.

Therefore, in order to prevent this, separate waveguides are used for transmission and reception, and they are placed side by side.
Their tips are spaced approximately 10 mm apart from each other so that they face the molten steel level surface C.

From the above, the present invention is advantageous in terms of cost because it only requires the installation of a microwave transmitter/receiver and a waveguide, and since no radiation is used, it has no effect on the human body and is easy to handle. It has the feature of being able to measure the molten steel level surface continuously without contact, even when it cannot be seen.

[Brief explanation of drawings]

Fig. 1 is a schematic side view of a drum-belt type continuous casting machine, Fig. 2 is a schematic plan view of the same continuous casting machine, and Fig. 3 is a vicinity of the rotating drum where a microwave level meter according to an embodiment of the present invention is installed. FIG. 4 is a schematic side view of the rotating drum and its vicinity. 1... Rotating drum, 1a... Flange, 2, 3
...Belt holding roller, 4...Belt tension roller, 5...Belt, 6...Tendishu, 7...
Nozzle, 8... Slab, 9, 10... Pinch roller, 11... Coil, 12... Microwave transmitter/receiver, 13... Microwave waveguide, 14... Molten steel in tundish, 15... In nozzle Molten steel.

Claims (1)

[Claims for Utility Model Registration] A drum/belt that pours molten steel from a nozzle into a mold space formed between a rotating drum mold and a belt that moves around the mold as the mold rotates. The type continuous casting machine includes a microwave transmitter/receiver that transmits microwaves and detects the phase difference between the reflected waves and a microwave transmitter/receiver whose base end is connected to the microwave transmitter/receiver and whose tip is connected between the belt and the nozzle. a waveguide bending and facing into the mold space from the upper space; A microwave level meter for a drum/belt type continuous casting machine, characterized in that it receives reflected waves from the microwave.