EP0078199A2 - Liquid distribution apparatus - Google Patents

Abstract

Liquid distribution apparatus, comprising at least one distribution ramp (12) and flow control means for adjusting the volumetric flow rate of the ramp. These control means comprise at least two fixed overflow pipes (24-34) determined to each generate different hydraulic pressures, the first (24) corresponding to the maximum flow capacity of the boom (12), and each other ( 34) corresponding to a fraction different from this maximum capacity; means (36) are provided for selectively activating the overflow pipes (24-34). The invention applies to the cooling of metal strips at the outlet of a hot strip rolling mill.

Description

The present invention relates to a liquid distribution device intended to improve the adjustment of the feed rate of a distribution ramp used to pour a treatment liquid onto an object. The invention is susceptible of numerous applications, but to expose it it will be presented here in the particular case of the cooling of a metal strip during its hot rolling or immediately after rolling.

In the operation of a continuous hot strip mill, and in particular its finishing train, two important factors are taken into account when the temperature of the strip is to be regulated by cooling. The temperature of a strip, on leaving the last stand of the finishing train must, for metallurgical reasons, be maintained at a value fixed in advance. Likewise at the time when the strip arrives at the reel from below, its temperature must also, always for metallurgical reasons, be maintained at a value fixed in advance, a value which is moreover different from the finishing temperature of the strip. . Formerly these two fundamental imperatives were obtained, on the one hand for the temperature at the exit of the finishing cage by regulating the speed of the finishing train, and on the other hand for the temperature at the entry of the rewinder by regulated watering d cooling water on the lower and upper sides of the strip after it leaves the last stand of the finishing train.

On the newer hot strip rolling mills, the demand for higher production, the need to laminate more elaborate and higher quality products led to a substantial increase in the dimensions and capacity of the strip cooling systems, and to equip them with more complex control means. This has resulted in extremely complicated, expensive and unreliable cooling systems. For example to meet the desire for automation and fast and precise control of the strip temperature, the strip temperature after the action of the outlet cooling system is controlled by a process control computer connected to hundreds electronic and hydraulic components.

In the past, but in a very limited way, fixed overflow pipes have been used generating hydraulic pressure to control 1st the quantity of liquid brought to the ramps of the cooling systems at the outlet of the hot strip mills; however, no attempt has ever been made to use such means for analog regulation of the refrigerant volume flow, with the use of several fixed overflow pipes capable of satisfying a whole range of temperatures for the hot strip train. Likewise, they were not used as a refrigeration station between cages.

The object of the present invention is therefore to provide an improved device for dispensing liquid which ensures the required volumetric flow rate with the flexibility and reliability necessary, but without requiring flow variation equipment; instead, it uses a system making it possible to obtain either a full flow, or more or less weak fractions of this full flow, all under the dependence of an all or nothing control system.

The invention therefore relates to a liquid distribution device, comprising at least one distribution ramp and flow control means for adjusting the volumetric flow rate of the ramp. According to the invention, these flow control means comprise at least two fixed overflow pipes determined to each generate different hydraulic pressures, the first corresponding to the maximum of the flow capacity of the boom, each other corresponding to a different fraction of this maximum capacity; the dispensing apparatus includes means for selectively activating the overflow pipes.

According to a particular embodiment of the invention, applied to the case of a distribution manifold producing a uniform curtain of coolant sprayed to cool it on a hot rolled metal strip, and in which two fixed overflow pipes are used , the pressure generated by the second overflow piping corresponds to half the flow capacity of the boom.

• La figure 1 est une vue en plan d'un système de refroidissement de bandes réalisé selon l'invention, avec tuyauteries multiples de trop plein, et appliqué à la sortie d'un train de bandes à chaud.
• La figure 2 est une coupe verticale selon II-II de la figure 1.
• La figure 3 est une vue en élévation d'un second mode de réalisation de l'invention.
• La figure 4 est une coupe verticale selon IV-IV de la figure 3.

The invention will be better understood by referring to embodiments given by way of examples and represented by the appended drawings.

• Figure 1 is a plan view of a strip cooling system produced according to the invention, with multiple overflow pipes, and applied to the outlet of a hot strip train.
• Figure 2 is a vertical section along II-II of Figure 1.
• Figure 3 is an elevational view of a second embodiment of the invention.
• Figure 4 is a vertical section along IV-IV of Figure 3.

Figures 1 and 2 show a strip cooling device on the output table of a hot strip mill not shown. Several of the horizontal rollers 10 of the output table are shown in phantom. The exit zone comprises a relatively large number of these cooling devices which are in the form of several horizontal rows of ramps. One of the important characteristics of the present invention which will be detailed lies in the advantage of being able to operate one or more of the rows at 100% of their maximum cooling capacity and the other rows at 50% of their maximum cooling capacity. , thus reducing by 50% the temperature variation of the strip at the inlet of the winder not shown.

FIG. 1 shows a certain number of upper ramps 12 for cooling the strip, of a common type of construction and designed to distribute over the upper surface of the strip the necessary quantity (GPM) of coolant, quantity dependent on the rolling mill. This type of ramp is determined so as to project a curtain of water of constant section from a certain height above the strip. A similar system of ramps which will be discussed later is provided for projecting water onto the lower surface of the strip. Although FIG. 1 only represents upper ramps 12, it can be seen in FIG. 2 that the system comprises an equal number of lower cooling ramps, the inlet pipes of which are marked 14 while the inlet pipes of the upper ramps are marked 16.

In each group or row, the ramps are connected to the feed distributors 18 and 20, both shown in FIGS. 1 and 2. The feed distributor 18, which relates to the upper ramps 12, is connected, on the left side of the Figures 1 and 2, to a supply pipe not shown, and on the right side of the figures to an elbow 22 through which the water is supplied to two fixed overflow pipes.

Refer to Figure 2 to follow the course of the water. Immediately after the bend 22, the water enters the first 24 of the two fixed overflow pipes arranged vertically; the piping 24 has been determined so that the water column that it retains corresponds to the hydraulic pressure necessary to drive the desired water flow (GPM), that is to say 100% of the capacity of the row of ramps . The water coming from the distributor 18 enters a central cylindrical element 26 of the overflow piping 24, and under certain conditions fills this central element until it overflows from the top. The overflow water then flows outside of the section 26, in the annular section 28, to the bottom of the pipe 24 from where it is then discharged through the flow conduit 30. C ' it is also in this zone that we find the support 32 which supports the overflow piping 24.

The second fixed overflow pipe 34 is mounted to the left of the pipe 24, and a two-way solenoid valve 36 is mounted on a pipe 38 which connects the two overflow pipes 24 and 34. The structure of the pipe overflow 34 is on the whole similar to that of the piping 24, with a central element 40 into which the water penetrates and can rise to form a column of water of predetermined height and fixed at half of that formed in the overflow pipe 24; it is thus possible to quickly and precisely choose the water flow rate to be supplied to the ramps 12, either 100% or 50% of the maximum capacity of the system. The ramps 12 being directly connected to the same feed distributor 18 as the overflow pipes 24 and 34, the hydraulic pressures generated in the two overflow pipes determine the volume of water brought to the ramps and distributed by them. this. The solenoid valve 36 is determined so that, when it is closed, the water cannot pass through the pipe 34; when it is open, the water passes through this pipe 34 so that the water which would pass through the pipe 24 is maintained at the same pressure generated by the water column of the pipe 34.

FIG. 2 represents a part of the electrical equipment 42 for controlling the solenoid valve 36. The discharge pipe 44 of the overflow pipe 34 is emptied into the discharge pipe of the overflow pipe 24 .

We will now refer to the flow control system of the lower booms which are not shown in the drawings. Their supply distributor 20 brings the water to an elbow 45 and to a set of two overflow pipes whose function and construction are similar to those of pipes 24 and 34. The overflow pipe 46, immediately after the elbow 45, is constructed so as to ensure the maximum volume capacity, ie 100 Z. The piping 48, which is smaller, provides 50% of the maximum capacity. We see at 50 the solenoid valve that connects them. These two overflow pipes 46 and 48 are provided with a drainage system quite similar to that of pipes 24 and 34; we see some a part under the reference 52 of FIG. 2.

During the operation of the cooling system described, it is advantageous to be able to combine the action of ramps operating at 100% flow followed by ramps at 50% flow, which theoretically reduces the temperature variation of the strip by 50 X level of the winder. The flow rate of the fluid is adjusted so that it is maximum in all the ramps of the row concerned, plus an additional approximately 5% to ensure the hydraulic pressure in all circumstances. Once the flow of this row of booms has been adjusted, it never needs to be changed again. This allows on-off control of the ramps, which is considerably simpler and more reliable than previous systems with variable flow control. The possibility of greater temperature variation accuracy, using a half flow or, if desired, another fraction of flow, makes it possible to operate with much more precise temperature settings than those obtained by current methods with variable flow.

It will also be noted that the present invention can be implemented in the form of a ramp with two overflow pipes, which can be installed between the stands of the rolling mill, where one can plan to use one or more ramps. It will also be noted that the system which has been described above by way of example with two overflow pipes generally provides the desired adjustment precision for all known applications on hot strip trains. If you wanted to obtain an even more precise adjustment, you could use additional overflow pipes ensuring finer degrees of adjustment.

Figures 3 and 4 illustrate a second embodiment of the invention. Instead of two separate overflow pipes as is the case in FIGS. 1 and 2, a compact construction is used here. The represented part of the overflow pipe 54 comprises a cylindrical central part marked generally by 56 and the upper part of which is open to allow the water to overflow between the internal wall of the pipe 54 and the external wall of the part 56 , with return to a drain pipe not shown. The lower part of the part 56 comprises a fixed element 58 which rotatably supports the upper element 60. These two elements 58 and 60 are provided with a series of conjugate openings, respectively 62 and 64, which when the rotation of the element 60 brings them into alignment, allow the water to overflow at the level of the openings 62 and 64 instead of flowing to the upper part of the part 60; we Thus creates two heights of water column in the overflow pipe 54. In Figure 4 the openings of the element 60 are shown in the closed position. The upper element 60 is rotated using a handle 66 at the end of a shaft 68 integral with the element 60 and held in a bearing 70. A locking pin 72 makes it possible to maintain the openings 64 at the desired angular position.

Of course, the invention is not strictly limited to the embodiment which has just been described by way of example, but it also covers the embodiments which would differ from it only in details, in variant embodiments or by the use of equivalent means.

Claims (8)

1. Liquid distribution device, comprising at least one distribution ramp and flow control means for adjusting the volumetric flow rate of the boom, characterized in that these flow control means comprise at least two fixed pipes too many full (24-34) determined to generate each of the different hydraulic pressures, the first (24) corresponding to the maximum of the flow capacity of the boom (12), each other (34) corresponding to a different fraction of this maximum of capacity ; and by the fact that it comprises means (36) for selectively enabling the overflow pipes (24-34) in action. 2. Distribution apparatus according to claim 1, applied in the case of a distribution ramp (12) producing a uniform curtain of coolant sprayed to cool it on a hot-rolled metal strip, and in which two excess fixed pipes are used full, characterized in that the pressure generated by the second overflow pipe (34) corresponds to half the flow capacity of the boom (12). 3. Distribution apparatus according to claim 2,
characterized in that the means for selectively activating the overflow pipes comprise a solenoid valve (36). 4. Dispensing apparatus according to claim 2,
characterized by the fact that it comprises two separate similar devices (18-20) for projecting the liquid respectively on the upper face and the lower face of the strip which passes between the two. 5. Distribution apparatus according to claim 2, and comprising several distribution ramps,
characterized in that the flow control means are determined to regulate the flow of all the booms. 6. Dispensing apparatus according to claim 2,
characterized by the fact that it comprises evacuation means (30) for receiving the liquid having overflowed from the overflow pipes. 7. A dispensing device according to claim 3,
characterized in that the solenoid valve (36) is determined so that in the closed position it activates only the overflow pipe (24) corresponding to the full flow capacity of the boom, and that in position open it activates the other overflow piping (34). 8. A dispensing device according to claim 2,
characterized by the fact that the ramps (12) are distributed in at least two rows,
and by the fact that it comprises means, of the all-or-nothing type, for activating each of the rows of ramps.

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