DE2401572A1 - WATERING PAN FOR SLOW POURING AND MOVING - Google Patents

Description

Jones & Laughlin Steel Corporation

3 Gateway Center

Pittsburgh, Pennsylavnia 15230

UNITED STATES.

Casting tub for slow casting and moving

The present invention relates to an apparatus and a method for slowly pouring liquids Materials with a 'tundish provided with several chambers, whereby the throughput of the liquid material through the tundish is dampened. The pouring tub is very suitable for uninterrupted pouring of metal strips.

The present invention relates generally to the discovery that a multi-chambered tundish can be used to convert an irregular inflow of liquid material into a uniform, liquid flow get low speed. An irregular inflow flow is understood to mean a flow with a temporarily very high flow and intermittently very low (including zero) throughput. It has been found that at least three chambers are necessary around achieve the desired conversion. According to the method, an infrequent, massive flow of liquid material flows into a first Introduced chamber of a vessel provided with several chambers and then flows, under the influence of gravity, into at least two subsequent chambers so that the irregularities in the level of the liquid material, which occur in the first chamber, be dampened. This method allows a low and almost constant liquid level in the last chamber of the container to obtain. By regulating the liquid level to a low hydrostatic pressure, a low hydrostatic pressure can be achieved constant liquid velocity can be obtained at the outlet from the last chamber. A stream of liquid with the above Properties is particularly suitable for use in areas which require these 'inflow properties. The uninterrupted one Giessexi of strips is one such process. The term "pour. / On strip" encompasses any method of pouring

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Strips in which liquid material is poured onto a pouring surface poured on, hardened on this and. away from the casting surface will. Examples of such methods include casting strips on the surfaces of rings, ribbons, drums, etc.

It is an object of the present invention to provide a method and an apparatus for converting an irregular Liquid flow into a continuous liquid flow to describe low speed.

Another object of the invention is the level or hydrostatic pressure in the part of the converting device ; in which the continuous current is created to keep it constant.

Another aim of the invention is to convert an irregular flow into a regular, laminar one not to describe splashing stream as these properties reduce oxidation or contamination of the liquid stream.

It is yet another object of the present invention to describe a method and an apparatus by which reduce the frequency of opening and closing of the feed device in which the irregular flow occurs. In the case of a socket lined with refractory material and provided with a stopper rod, this is particularly desirable since a decrease in the frequency of opening and closing of the stopper rod increases the risk of leakage and refractory Reduced erosion at the stopper-spout interface.

It is yet another object of the present invention to describe a method and apparatus which openings can have maximum size. Such openings have the advantage that they are during the procedure and after Do not block the closing of the device. This makes it easier to start up the device.

It is also advantageous to keep the number of chambers of the container as small as possible for the construction and the Facilitate maintenance. For a better understanding of the invention, reference is made to the following description and the enclosed figures in which

Fig. 1 is a photograph showing remelting the bottom surface of a cast metal strip shows which one with a high velocity tundish stream

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- 3 -. .
was poured;

Figure 2 illustrates the symbols of a mathematical model of the tundish system;

Fig. 3 shows the dynamic behavior of a tundish provided with 3 chambers, this behavior from a Computer model emerged for certain conditions;

4 shows a front view of a tundish with three chambers;

Fig. 5 is a plan view of a tundish with 3 chambers represents;

Fig. 6 shows an overall view of the metal inflow system which is a stopper pan, a pouring pan and a Ring casting system includes.

The present invention relates to a method and a tundish device with which an irregular liquid flow of acceptable frequency can be converted into a relatively constant flow of low speed. In order to obtain the desired flow properties, a fairly constant, low liquid level or liquid pressure must be maintained in the tundish chamber from which the liquid emerges. The speed at which the liquid flow emerges from the chamber is given by the diameter of the drain or the disk opening and the pressure level above the drain by the following equation: ι

where V = speed in cm per second; V = c *> / 2gh c = total opening (or discharge) flow coefficient g = 966 cm / sec.

h = liquid height above the opening cm.

With a liquid height of 30 »5 cm above the drain is e.g. at

c = 0.70 a liquid flow with an average velocity of 171> 4 cm per second.

Before the present invention, it was difficult to regulate the liquid level in a tundish. Such tundish devices led as material inflow sources for continuous casting of metal strips at undesirably high flow velocities. For example goes out Studies of cast steel metal strips indicate that a high velocity stream elongates the cast melt and

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: _ Ζμ _

part of the already formed metal strip directly under the

■ Electricity melts again. This shows up in the form of separate solid spots on the lower surface of the strip which in

'Cast the lower surface of the strip to rope. In this context, reference is made to the accompanying photograph (Fig. 1) of a cast metal strip using the best known '! Em-Ring metal strip casting process'. ¹ After the stream

'penetrated the casting melt and the partially cast strip the current hits a part of the cast ring which has already absorbed heat from the strip that has just been cast. This additional heat increases the surface temperature of the bing to an undesirably high value and thus contributes to a Distortion of the ring surface. In extreme cases, e.g. if the cast ring is stopped in an emergency, the current can affect the strip melt the ring or cause localized melting of the ring. This shows that a method and a device by which a constant low speed current can be obtained are of paramount importance around the above Solving problems, especially when casting metal strips with a high melting point such as steel. To solve this problem the hydrostatic pressure across the pouring opening of the tundish must be as low as possible of the acceptable flow properties corresponds to be reduced.

From various studies it emerged that a tundish was divided into at least 3 chambers located one behind the other divided, which chambers are connected to one another by large, individual openings, a stream of the desired property guaranteed. Although an irregular inflow leads to large fluctuations in the first chamber, these will Fluctuations in the subsequent chambers are quickly dampened.

It must also be pointed out that if the surface area of a tundish with a chamber is large is enough, a single chamber would theoretically suffice to obtain the desired flow properties. This would, however requires a tundish with such large dimensions that it is impractical and impractical for the present invention and other methods would be uneconomical. The device of the present invention not only dampens regularly occurring, but also irregular ones occurring irregularities. This is special

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^: Importance when manually controlling the tub plug rod

will.

■ In order was the "dynamic behavior of the \ system described above, predict a computer model for 3 and 4-chamber; systems worked out. The models were worked out using the differential equations of the hydraulic system. By

Consideration of the difference between the openings and the ; Net changes in pressure head in each chamber ; Inflow minus outflow can be shown that:

^(a o ^c o

^(a o ^c o

CA ₁

2g)

German

S_

H-,

(D

(2)

7 ^ T ⁷

Kl

ie

_2 (3)

German

(A,

V ^ p - ^ - Pit

ie,

7 < ^h 3 ⁼ "dt

C A,

ie

German

C5)

where the above symbols are defined in FIG.

It can be seen from FIG. 2 that the above equations are suitable for calculating a four-chamber tundish, each chamber being numbered in the figure. Although these equations are not linear, they can easily be programmed for computational solution by applying various initial conditions. The condition of the discontinuous inflow from the vessel 0 in chamber 1 of FIG. 2 can be used if a time cycle of constant period _{is assumed in which V Q} is set equal to zero in any particular part.

If the subdivision of the chambers 2 and 3 of FIG omitted the equations simplify to:

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A ₀ JY ^ o " dt

» F £ y -

(D

^c o V ^ J v / T - ^ ^a i ^c i V ² ^> fV ⁷ ^ = ^dh i (2)

Ca _n C ₁ V 2 ^). (a _z c _z 1/2) r— ie ^, / .. ν

^ 4 - German

Figure 3 is "a graph of the results a three-chamber tundish computer model for some operating cycles. The conditions of the model were as follows:

a. Initial pressure height in the tub = 76.2 cm

b. The liquid surface in the tub is assumed to be constant 4528 cm ²

c. Diameter of the tub drain 3il8 cm, flow coefficient = 1.0

d. Initial pressure head in all tundish chambers =

e. Surfaces of chambers 1 and 3 equal 633, respectively ο

921 cm. The surface of the chamber 4 varies depending on the height of the liquid (minimum 174.08 cm).

f. Disc drains or openings which connect chambers 1 and 3 and 3 and 4 are equal to 2.54 cm in diameter Flow coefficient assumed to be constant 0.7

G. Drain chamber 4 equal to 2.85 cm in diameter, b .. tub cycle time = 30 seconds

i. "Ratio tub time / total cycle = 1/6.

From the jig. 3 shows that a three-chamber pouring tub causes substantial damping in the intermediate chamber 3 and that the pressure level fluctuations in the chamber 4 practically equal 0 are.

The above computer approach resulted in a plexiglass model consisting of 4 chambers which were opened through individual openings connected were made and attempts made using water as the liquid material. Large fluctuations in

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Water levels in the first chamber (inflow chamber) were attenuated to 0 up to the fourth or end chamber (outflow chamber). Thus the reliability of the computer model was proven. A three-chamber model
was also examined. Although here the total damping effect
The results were satisfactory but not complete. Furthermore, a three-chamber design has various advantages in terms of simplifying the internal construction and the
Operation of the apparatus. Satisfactory results have also been achieved with liquid steel and a tundish lined with refractory material.

This shows that a tundish with at least 3 chambers is necessary to achieve the desired damping effect
obtained which leads to a relatively constant flow of liquid
low or minimum speed. Besides the above
Considerations also indicate that a tundish with 3 chambers
represents a preferred embodiment of the invention. Figure 4- is a front view of the preferred tundish. The tundish consists of a container 5 which is lined with a refractory material 6 when high temperature liquid, such as steel, is used. The container has a generally sloping bottom and
Side walls. The container 5 is in chambers 1, 2 and 3 through
Subdivisions 7 and 8 divided. Chamber 1 is the first
Chamber in which the liquid material is introduced.
Chamber 3 represents an intermediate chamber and chamber 4- represents the end chamber from which the liquid material flows off. Drainage means, preferably in the form of a cast, are in the
The bottom of the end chamber A is let in to drain off the liquid material. It is clear to the person skilled in the art that the drainage means also come from
can consist of several casts. Openings 10 and 11 are in
the subdivisions 7 and 8 let in to connect the chambers 1 and 3 and 4- with each other zx . This creates a flow of fluid
guaranteed between the different chambers. Preferably
the openings are let in near the lower part of the subdivisions to minimize the oxidation of the liquid material
and environmental pollution. Such
Arrangement is also advantageous when handling metal liquids as a protective layer on the liquid material
remains largely unaffected by the flow of metal in the various chambers. The openings 10 and 11 also have a

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quite, large diameter to a "blockage by, various to prevent solid contamination during operation and when the equipment is switched off. The openings are like that let in that they are not directly in the direction of the current, with respect to each other. In other words the openings are laterally, offset to the direction of flow. This arrangement is used to a transfer of the flow rate of the liquid from one chamber to the other to reduce the desired ■ To obtain a damping effect, ßtrömungsablenkmittel 12 are preferably built into the end chamber 4. Suitable means include a baffle plate which is embedded in the bottom of the end chamber is. These deflection means reduce the creation of undesirable vortex conditions at the drainage openings 9 · vortex conditions could lead to undesirable erosion of the casts, poor drainage properties such as splashing and excessive reoxidation or contamination of the liquid.

] fig. Figure 5 depicts a top view of the preferred three compartment tundish The offset of the openings in the subdivisions can be clearly seen from this figure.

Fig. 6 illustrates the use of a three-chamber tundish

22 with the chambers 1, 3 and 4 in connection with a pan 20 lined with refractory material and provided with a Rod stopper 22 represents an irregular, interrupted flow of liquid material from the pan into the first chamber 1 the tundish flows. The tundish 22 can with a lid

23 and burner openings 24, 25 may be provided if additional Heat supply to warm up the liquid material is desired. The irregular flow of liquid material enters the first tundish chamber 1 and flows from there through the chambers 3 and 4 through the spout 26 to the casting device, e.g. a ring casting device 27 ·

As previously indicated, the invention also describes a method with which a low velocity liquid flow can be obtained. The process consists of feeding liquid material in an irregular manner a first chamber of a vessel or container provided with several chambers made of many materials under the influence of gravity flows through at least one intermediate and one end chamber around the clock regularities which occur in the first chamber

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steam, the liquid finally flowing out of the end chamber under gravity. Through this procedure can be special a pouring stream with the properties which are obtained at Metal strip casting of ferrous or non-ferrous metals such as steel, copper, aluminum, etc. are advantageous. One particular embodiment of the invention describes a deflection of the liquid flow before exiting the end chamber so that undesirable yortex flow conditions when exiting the Liquid can be avoided from the end chamber.

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Claims (1)

: - 10 - ^: PATENT CLAIMS : 1. A tundish with which a low-speed flow of liquid can be • obtained, characterized by: y a. a container (5) for ^{containing a liquid:} material having side walls (6) and a generally sloping bottom; j b. Partitions (7> 8) attached to the floor and. the side walls which the container in at least 3 chambers (1, 3j 4), with the chambers a first chamber (l) in . which the liquid material is introduced, at least one. Intermediate chamber (3) and a header (4) from which the liquid flows out ■■ material comprises; c. Drainage means (9) in the end chamber (4) from which the liquid material drains; d. Openings (10, 11) let into the subdivisions (7, 8) to connect the chambers (1 + 3; 3 + 4-) with one another ^: so that the liquid material under the influence of gravity from: the first chamber (l) in the intermediate chamber (3) and flows out of the intermediate chamber into the end chamber (4). ^! 2. tundish according to claim 1, characterized in that. the container (5) has 3 chambers (1,3,4). 3. Casting tub according to claim 1, characterized in that Stromabienkmittel (12) in the end chamber (4) are attached to ■ to reduce the eddies occurring in the 'liquid material when entering the discharge means (9). 4. The tundish according to claim 1, characterized in that the openings (10, 11) in the lower part of the subdivisions (7 »8) are embedded. 5 ·. A pouring trough according to claim 1, characterized in that it is in communication with means (20) which introduce different amounts of liquid material into the first chamber (1) and with a device for continuous casting of metal strips (27) into which the liquid material flows and is poured. 6. A method by which a low velocity liquid flow is obtained with the apparatus of claims, marked by a. Introduction of a liquid material in different ■ Quantities in a first chamber (1) of a container (5) provided with several chambers (1, 3 »4); A09830 / 0809 b. Passing the liquid material from the first chamber (1) into an intermediate chamber (3) under the influence of gravity around the irregular texts in the liquid level which in the first chamber (l) occur to dampen; c. Directing the liquid material from the intermediate ' Chamber (3) into an end chamber (4-) under gravity so that the irregularities in the level of the liquid.Material are further dampened and a relatively constant liquid level is obtained in the end chamber (4); d. Drain the liquid material from the end chamber '(4) in the form of a low-velocity stream under heavy • force. 7. The method according to claim 6, characterized in that the liquid material is metal. 8. The method according to claim 7 »characterized in that the liquid metal is ferrous metal .. ■ 9. Method according to Claim 6, characterized by deflection of the liquid metal flow in the end chamber (4) to reduce the eddies in the liquid flow, thereby reducing the risk the formation of a vortex in the liquid material which flows out of the end chamber (4) is reduced. 10. The method according to claims 6 to 9 »characterized that the liquid material is drained from the end chamber (4) and a device for continuous pouring is fed by metal strips (27). 409830/0809 Blank page