US3360202A

US3360202A - Uniform thin fluid sheet type spray device

Info

Publication number: US3360202A
Application number: US484616A
Authority: US
Inventors: Harold L Taylor; John M Marshall
Original assignee: Inland Steel Co
Current assignee: Inland Steel Co
Priority date: 1965-09-02
Filing date: 1965-09-02
Publication date: 1967-12-26
Anticipated expiration: 1984-12-26

Description

Dec. 26, 1967 H. TAYLOR ETAL 3,360,202

UNIFORM THIN FLUID SHEET TYPE SPRAY DEVICE Filed Sept. 2, 1965 Ing/enf@ 713: Havo Cil/ T @Z077 JUL WMM/Vars 39M Yx QM United States Patent O 3,360,202 UNIFORM THIN FLUID SHEET TYPE SPRAY DEVICE Harold L. Taylor, Hammond, Ind., and John M. Marshall,

South Holland, Ill., assignors to Inland Steel Company,

Chicago, Ill., a corporation of Delaware Filed Sept. 2, 1965, Ser. No. 484,616 4 Claims. (Cl. 239-455) ABSTRACT F THE DISCLSURE traverses a tortuous path in flowing from the inlet to y the discharge orifice.

This invention relates to a novel lluid spray device which is particularly useful to obtain a uniform fluid stream in the form of a thin sheet or curtain having substantial width.

-There are many circumstances in which it is desirable to impinge a liquid or gas against a strip of material or other object. For example, in the steel industry'it is frequently necessary to i-mpinge a liquid or gas across the width of a moving metal strip. A typical instance is the continuous cooling or quenching of a moving hot steel strip by means of water or other quench liquid. Another example is the impingement of steam or a gas against the surface of a coated metal strip as it emerges from the coating bath of a continuous hot dip coating line for the purpose of inlluencing the appearance or thickness of the coating.

Where the strip being treated is relatively wide, it has been customary in the past to provide a plurality of spray nozzles disposed in carefully spaced relation across the width of the strip so as to provide either an overlapping spray pattern or a contiguous spray pattern as desired. However, in either case it is diillcult to insure uniform fluid ilow across the Width of the strip, and such arrangements are not satisfactory where it is necessary to have a highly uniform fluid flow across the strip, e.g. where a completely uniform cooling or quench action is desired. The present invention overcomes the deficiencies of conventional multiple spray devices by means of a novel iluid spray which is adapted to deliver a unitary iluid stream in the form of a thin sheet or curtain having any desired width and with complete uniformity of fluid ilow across the entire width of the stream.

Accordingly, a primary object of the invention is to provide a novel and improved lluid spray device which is adapted to deliver` a unitary and uniform fluid stream in the form of a thin sheet or curtain having any desired width.

Another object of the invention is to provide a novel and improved spray device for uniformly impinging a relatively wide stream of liquid or gas against a moving strip or other object.

A further object of the invention is to provide a novel and improved fluid spray device having an elongated rectangular discharge orifice adapted to deliver a fluid stream in the form of a thin unitary sheet or curtain of substantial width with a high ldegree of uniformity of fluid flow across the width thereof.

Other objects and advantages of the present invention will be come apparent from the subsequent detailed description taken in conjunction with the accompanying drawing, wherein:

FIG. 1 is a schematic diagram of a portion of a continuous heat treating and quenching line for steel strip;

FIG. 2 is an enlarged vertical sectional View of a portion of the apparatus shown in FIG. 1;

FIG. 3 is an enlarged fragmentary internal view taken along the line 3-3 of FIG. 2; and

FIG. 4 is an enlarged cross-sectional View taken along the line 4 4 of FIG. 3.

For the purposes of illustration only, the drawing shows one specific embodiment of the spray device cornprising the present invention as used in a continuous heat treating and quenching line for steel strip. For example, the illustrated embodhnent of the invention may comprise a continuous line for making martensitic steel strip, as more fully described in the copending application of Harold L. Taylor, Serial No. 426,277, filed January 18, 1965.

As seen in FIG. l, a steel strip10 is fed downwardly through a furnace 11 where the steel strip is heated to a uniform temperature above the A1 critical point so that the steel is at least partially austenitized. This temperature may range from about 1330 F. to as high as about 2100 F., dependent upon the carbon content, but from a practical standpoint effective results may be obtainedwithin the range of from about 1330 F. to about 1750 F. In order to obtain a fully martensitic product the steel strip must be heated above the A3 critical point, Le. to a temperature within the range of from about 1525 F. to about 2100 F. and particularly within the range of from about 1525 F. to about 1750 F. Immediately upon leaving the furnace 11 the heated strip passes into a quench apparatus 12 (more fully described below) where the strip is rapidly quenched to ambient or room temperature so as to obtain at least a partially martensitic microstructure. vThe oxide scale formed during quenching is subsequently removed from the surface of the strip by pickling in an acid dip 13.

As shown in FIG. 2, the quench apparatus 12 comprises a tank 15 provided with a drain 16, a strip exit chute 17, and a sinker roll 1S around which the strip 1l) is trained. Water, or other quench liquid, is supplied continuously to the tank 15 through an inlet 19. Extending upwardly from the tank 15 is an elongated conduit section 21 of rectangular cross-section which provides a restricted quench channel 22. Quench water flows upwardly through the conduit 21 and spills over the upper edge into a trough 23 having a rectangular cross-section and surrounding the conduit 21. An upright rectangular baille or Weir 24 extends upwardly from the bottom of the trough 23 surrounding the conduit 21 and terminating below the upper edge of the conduit 21. Extending downwardly from the outlet end of the furnace 11 is a tubular connecting or seal section 26 the lower end of which extends into the trough 23 below the upper edge of the weir 24 and disposed between the conduit 21 and the Weir 24. Ellluent water llows over the upper edge of the Weir 24 and is discharged at one end of the trough 23 through drain lines (not shown) extending from the bottom of the trough.

Since the water level in the space between the weir 24 and the conduit 21 is determined by the height of the Weir 24, it will be recognized that the lower end of the connecting or seal section 26 is sealed by the water confined in the rectangular Weir 24 so as to prevent infiltration of air into the furnace 11. If desired, a reducing or other non-oxidizing gas may be supplied to the section 26 (by means not shown) for passage upwardly through the furnace 11, thereby preventing oxidation of the strip. A plurality of

view ports

27 and 28 are provided in the tubu- 3 lar section 26 and the conduit 21, respectively, to permit observation of the quench action.

Closely adjacent the upper end of the conduit 21, a plurality of submerged spray devices 29 are provided which comprise the subject matter of the present invention. The spray devices 29 are mounted in the opposite walls of the conduit 21 for directing streams of liquid toward opposite sides of the strip across the entire width thereof. In this case, two superimposed spray units 29 are mounted at each side of the strip 10, but any desired number of such units may be used. Each unit 29 is supplied with water or other quench liquid by means of a supply conduit 31 having a control valve 32 and communicating with a main header 33.

As best seen in FIGS. 3 and 4, each spray unit 29 cornprises a pair of elongated angle members (FIG. 4) welded together to provide an elongated tubular box-like structure having a front wall 34, a rear wall 36, an upper wall 37, and a bottom wall 38. End closure plates 39 (FIG. 3) are secured to the opposite ends of the box-like structure. The quench liquid supply conduit 31 extends into an openin g in the rear wall 36, and an elongated rectangular discharge slot 41 is provided in the front wall 34 extending substantially the entire length of the spray unit 29 and across the entire width of the strip 10.

The interior of the enclosure is provided with bafiie means which in this instance comprises a pair of elongated rectangular baille plates 4Z and 43 extending between the end plates 39 in transversely spaced relation between the front wall 34 and the rear wall 36. As seen in FIG. 4, the bafiie plate 42 depends from the upper wall 37 and its inner free longitudinal edge is straight and uninterrupted and is spaced slightly from the bottom wall 38, as at 44, whereas the baffle plate 43 extends upwardly from the bottom wall 38 and its inner free longitudinal edge, also straight and uninterrupted, is spaced slightly from the upper wall 37, as at 46. As also shown in FIG. 4, the outer longitudinal edges of the

baffie plates

42 and 43 are rigidly secured, as by

welding

47 and 48, to the

respective walls

37 and 38.

Preferably, the spray device also comprises a pair of elongated adjustable orifice strips 49 movably mounted on the outside of the front wall 34 by means of a plurality of screws 51 extending through transverse slots 52 in the strips 49 into threaded openings in the front wall 34. By means of the slot and screw arrangement the innermost longitudinal edges of the strips 49 are spaced apart to any desired extent to provide an elongated rectangular or slit orifice 53 overlying the discharge slot 41. A pair of end blocks 54 (FIG. 3) are also secured to the front wall 34 in fixed relation at the opposite ends of the adjustable orifice strips 49. The liquid coolant in passing from the inlet 31 to the orifice 53 follows a tortuous path in which the direction of fiow is reversed several times, as indicated by the arrows in FIG. 4, thereby insuring a uniform flow of liquid across the entire length of the orifice opening 53. Moreover, the restricted spacing at 44 and 46 between the free longitudinal edges of the bafiies 42-43 and the walls 38-37 serves to trap any large particles of foreign material and thereby prevents obstruction of the orifice 53. If desired, the strips 49 may be adjusted so that the

bafiie clearances

44 and 46 are narrower or more restricted than the orifice 53, thereby insuring that no foreign particles will clog the orifice 53.

As will be evident particularly from FIG. 2, the submerged spray units 29 are mounted in suitable openings in the walls of the conduit 21 with the orifice strips 49 projecting slightly into the channel 22 so that thin sheets or curtains of water are directed from the slit orifices 53 substantially perpendicularly toward opposite sides of the strip 10. In fluid kinematics terminology, the unitary sheet or curtain of water from an elongated rectangular orifice, such as 53, may be characterized as having two-dimensional fiow, i.e. the flow is identical in parallel planes so as to extend uniformly across the width of the strip 10.

As the strip 10 moves downwardly from the furnace 11, it passes through the seal section 26 and enters the upper end of the water-filled quench channel 22 where it is immediately immersed in the upwardly fiowing stream of water. In addition, the submerged spray units 29 direct water streams against the strip in a direction generally perpendicular to the path of movement of the strip, thereby creating a high degree of turbulence in the uppermost portion or strip entry end of the quench channel. As the strip 10 leaves the lower end of the conduit section 21, it enters the tank 15, passes beneath the roll 18, and emerges from the exit chute 17.

In the production of martensitic steel strip, uniformity of quench action is essential not only for the sake of obtaining a strip having uniform microstructure and uniform physical properties but also to avoid warpage and distortion of the strip. In the system herein illustrated, the use of the spray units 29 contributes materially to the desired uniformity of quenching because of the ability of the spray device 29 to deliver a relatively thin unitary sheet or curtain of liquid having uniform ow across the entire width of the strip being quenched.

As heretofore described, the discharge orifice 53 of the spray device is rectangular in shape with the length of the orifice being much greater than the height thereof. The

baflie plates

42 and 43 function to divide the hollow interior of the spray device into a plurality of elongated parallel chambers which are interconnected in series relation by restricted fluid passage means. Thus, as shown in FIG. 4, the enclosure is divided into

chambers

56, 57, and 58 which are connected by the restricted

clearances

44 and 46. Since the

baflie plates

42 and 43 are disposed in the path of fiuid fiow between the inlet 31 and the outlet 41-53, and since the

clearances

44 and 46 of adjacent baiiie plates are located at opposite walls of the enclosure, the fluid is forced to follow a tortuous flow path with several reversals in the direction of flow. Inasmuch as the

baffle plates

42 and 43 extend throughout the entire length of the spray device 29 between the end walls 39 thereof, the parallel chambers 56-57-58 defined by the baffle plates and the walls of the enclosure extend uninterruptedly along and are coextensive with the length of the interior of the spray device. Likewise, the restricted

fluid passages

44 and 46 extend uninterruptedly along and are coextensive with the length of the interior of the spray device. Consequently, there are no obstructions to fiuid fiow tending to create non-uniformity of iiow. It is particularly important that the chamber 58 at the upstream side of the outlet 41-53 be free of all obstructions to flow so that the resultant thin curtain or sheet of fluid issuing from the discharge orifice 53 has complete uniformity of fluid flow from one end of the orifice to the other.

Although in the illustrated embodiment of the invention the internal bafiie means comprises a pair of bafiie plates dividing the interior of the spray device into three parallel chambers, it will be understood that any desired number of baflie plates may be used. Furthermore, although the invention has been illustrated and described in connection with a spray device for treating a moving strip, it should be understood that the invention is also useful in other applications requiring a highly uniform fiuid stream extending over a substantial width or length of the object being treated. For example, in the cold rolling of steel or other metals, it is common practice to utilize relatively long rolls which must be cooled during the rolling operation by suitable sprays. The present invention affords a highly uniform cooling action as compared with conventional spray devices heretofore used.

We claim:

1. A fluid spray device for discharging a uniform thin sheet of fluid comprising:

an elongated box-like structure having end closures and two pairs of longitudinally extending, oppositely spaced, parallel walls ydefining an enclosure with a rectangular transverse cross-section,

a plurality of fixed internal bellies rigidly mounted within said enclosure and comprising elongated rectangular plate portions extending the full length of said enclosure between said end closures, each of said plate portions having an elongated, straight,

uninterrupted, free edge,

said plate portions being disposed in parallel transversely spaced relation with respect to each other and with respect to and betwen the walls of one of said pairs of walls,

the interior of said enclosure being substantially free of uid flow obstructions except for said baflles, whereby said plate portions divide the interior of said enclosure into a plurality of elongated parallel chambers extending uninterruptedly between said end closures,

the free edge of one of said plate portions being spaced uniformly from one of the walls of the other of said pairs of walls, and the free edge of an adjacent plate portion being spaced uniformly from the opposite wall of said other pair of walls, thereby dening restricted fluid passages interconnecting the chambers at opposite sides of the respective plate portions, said fluid passages extending uninterruptedly between said end closures and being arranged alternately adjacent the oppositely spaced walls of said other pair of walls,

fluid inlet means in one of the walls of said one pair of walls, and

means defining an elongated, narrow, substantially rectangular discharge orifice at the opposite wall of said one pair of walls, said orifice extending uninterruptedly along substantially the entire length of said enclosure,

whereby iluid introduced at said inlet means flows in a tortuous path through said chambers and through the interconnecting uid passages and is discharged from said orifice as a uniform thin fluid sheet.

2. The device of claim 1 further characterized in that said bales `comprise a pair of rectangular plates each having oppositely disposed longitudinal edges, one of said plates being rigidly securing along one of its longitudinal edges to one of the walls of said other pair of Walls and having its opposite .longitudinal edge spaced from the opposite wall of said other pair of walls, and the other of said plates being rigidly secured along one of its longitudinal edges to said opposite wall of said other pair of walls and having its opposite longitudinal edge spaced from said one Wall of said other pair of Walls.

3. The device of claim 1 further characterized by the provision of adjustable means on said opposite wall of said one pair of Walls for regulating the size of the narrow dimension of said orice.

4. The device of claim 3 further characterized in that said opposite wall of said one pair of walls is provided with an elongated slot, and said adjustable means comprises a pair of elongated strips adjustably mounted in parallel relation at the outside of said opposite wall of said one pair of walls for movement toward and away from each other, said strips having their adjacent longitudinal edges overlying said slot and defining therebetween an elongated adjustable orifice for controlling the thickness of the uid sheet discharged from said device.

References Cited UNITED STATES PATENTS 1,078,588 11/1913 McElwaine 239-413 1,121,873 12/1914 Roth 239-455 X 1,391,047 9/1921 COteIa 239-451 X 1,641,888 9/1927 Hollemau 239-597 X 2,684,690 7/1954 Lee 239-5905 X 2,926,384 3/1960 Hertz et al 239-590.5 X 3,221,996 12/ 1965 Emmert et al Z39-590 M. HENSON WOOD, I R., Primary Examiner.

V. C. WILKS, Examiner.

Claims

1. A FLUID SPRAY DEVICE FOR DISCHARGING A UNIFORM THIN SHEET OF FLUID COMPRISING: AN ELONGATED BOX-LIKE STRUCTURE HAVING END CLOSURES AND TWO PAIRS OF LONGITUDINALLY EXTENDING, OPPOSITELY SPACED, PARALLEL WALLS DEFINING AN ENCLOSURE WITH A RECTANGULAR TRANSVERSE CROSS-SECTION, A PLURALITY OF FIXED INTERNAL BAFFLES RIGIDLY MOUNTED WITHIN SAID ENCLOSURE AND COMPRISING ELONGATED RECTANGULAR PLATE PORTIONS EXTENDING THE FULL LENGTH OF SAID ENCLOSURE BETWEEN SAID END CLOSURES, EACH OF SAID PLATE PORTIONS HAVING AN ELONGATED, STRAIGHT, UNINTERRUPTED, FREE EDGE, SAID PLATE PORTIONS BEING DISPOSED IN PARALLEL TRANSVERSELY SPACED RELATION WITH RESPECT TO EACH OTHER AND WITH RESPECT TO AND BETWEEN THE WALLS OF ONE OF SAID PAIRS OF WALLS, THE INTERIOR OF SAID ENCLOSURE BEING SUBSTANTIALLY FREE OF FLUID FLOW OBSTRUCTIONS EXCEPT FOR SAID BAFFLES, WHEREBY SAID PLATE PORTIONS DIVIDE THE INTERIOR OF SAID ENCLOSURE INTO A PLURALITY OF ELONGATED PARALLEL CHAMBERS EXTENDING UNINTERRUPTEDLY BETWEEN SAID END CLOSURES, THE FREE EDGE OF ONE OF SAID PLATE PORTIONS BEING SPACED UNIFORMLY FROM ONE OF THE WALLS OF THE OTHER OF