US2678815A - Coil separator - Google Patents

Description

`May 18, 1954 H. F. RADLlNsKl COIL SEPARATOR Filed Feb. 5, 1951 Patented May i8, 1954 PATENT OFFICE n COIL SEPARATOR Harry F. Radlinski, Toledo, Ohio,

Surface Combustion Corporation, Toledo,

l. Claim.

This invention relates to apparatus for annealing a stack of cylindrical coils or steel strip. It has long been recognized that radial heat flow through the laminat-ions of a strip coil is relatively slow as compared to the heat flow parallel to the laminations heated from the strip edges, and it has been proposed to provide channelled separators between the coils to permit heat to be applied to the edges of the laminations by hot gases flowing through the channels ci said separators. Such channels have been generally radial so that a ian at one end oi a central passage through the coils may induce draft therein to provide substantially radial gas now through said channels. The channels have been formed by ribs on an annular plate or between annular plates for support by the plate. Such plates are subject to severe distortion in service due to rapid heating of the ribs by the hot gases in the channels while the coils are yet cold. In such a case the ribs, and also the plate, tend to expand due to heat while severely restrained by the cold heavy coils, and severe twisting and wrinlrling of the plate results.

The present invention aims to provide an irnproved coil separator and to avoid the foregoing diiiiculties in a relatively simple and practical manner.

For a consideration of what l consider to be novel and my invention, attention is directed to the following specification and the concluding claim thereof.

1n the accompanying of this specincation:

rawings forming part Fig. l is a vertical sectional View of a typical a stack or" coiled strip.

separator ernfurnace for annealing Fig. 2 is a plan view oi a coil bodying the present invention.

Fig. 3 illustrates a certain combinational relationship between the coil separator and the inner cover of the coil annealing furnace.

Fig. 4 is a fragmentary detail view oi the inner edge of the separator.

Fig. 5 further illustrates the combinational relationship shown in Fig. 3.

The annealing furnace shown in Fig. l coinprises a portable heating hood iii for heating a bell type mulfile or inner annealing cover Il disposed over a stack or" cylindrical coils i2 of sheet steel which is to be annealed. The thick ness of the laminations of the coils has been greatly exaggerated for illustrative purposes. The source of heat carried by the heating hood will ordinarily comprise internally fired radiant tubes I3 distributed along the sidewalls of the assigner to Ohio,

hood. For simplicity of illustration only the upper and lower tubes are shown, but as indicated by broken lines lA there will be additional tubes therebetween.

The base of the furnace is generally indicated at l5 and comprises an upstanding peripheral wall IE on which the heating hood l0 is seated, the seat being surrounded by a sand seal il. The furnace base also comprises a stand for supporting a column of coils l2, the stand being shown in elevation except for the top plate 2| which is shown in section. This top plate has a central aperture coaxial with a circulating ian 22 which is driven by a motor 23 carried by the underside of the coil stand. The top plate 2i is spaced from the lower portion of the coil stand by radial spacers 2t whereby to provide radial gas passages below said plate for the gas circulated by the ian 22. The inner cover il is removably supported on a ledge 25 which surrounds the coil stand and the foot 42 of the inner cover is shown as surrounded by a layer of granular sealing material 2t to prevent objectionable leakage of gas from the inner cover. Some seepage of gas from the inner cover is not objectionable, but rather desirable. A non-oxidizing gas is supplied to the inner cover by a supply pipe not shown but which extends through the coil stand 20 from below.

llt will be understood that unless the coils l2 are spaced apart to provide gas flow passages therebetween all of the gases circulated by the ian 22 which is of the radial discharge type must enter at the top oi the coil stack for downward flow therein. The coils are spaced apart by separators 21 and an orice plate 30 is placed on top of the coil stack. The purpose of the oririce plate is to restrict the entry oi circulated gas to the inside of the stack by way of the top thereof whereby to cause part of the circulated gases to flow laterally inward through channels formed by the coil separators 2l.

Referring now more particularly to Figs. 2, 4 and 5, the improved coil separator 21 comprises a top planar series oi ribs 3l curved in a clock wise direction and a bottom planar series of ribs 32 curved in a counterclockwise direction. The ribs 3l are superimposed on ribs 32 and welded thereto by weldments 33 both at the respective inner ends 35 and 36 of the ribs and the outer ends 31 and 38 of the ribs. A bumper 34 in segment form is secured to the outer ends of the ribs 3| and 32 by weldments 44.

The ribs 3l and 32 are curved in the form of circular arcs approximating involute curves to provide passages between adjacent ribs of each planar series which are of substantially uniform size from the inner end to the outer end of the passage. In this way substantially uniform gas velocities through the passages are maintained with resultant uniformity of heat transfer from the gases to the coils I2. The curved bars also serve to provide rigidity due to the curves as well as maintaining uniform conditions from one passage to another'. It will be understood that the bumper 34 is sufficiently spaced from the coils l2, or of suiciently small diameter relative to the width of the bars or ribs 3| and 32, to allow gas to pass over said bumper and into said passages.

Fig. 3 illustrates the functional purpose of the bumper 3ft. In cases where the inner cover Il comprises a corrugated vertical wall 4|, it is usually provided with a depending skirt i2 which in service is embedded in a sand seal 29, and an annular plate i9 joining the cover wall and the skirt in a gas tight manner. On the inside of the convolutions of the corrugated wall lil the plate 40 forms a series of shelves wherein the absence of the bumper 39 an exposed and extended rib of a coil separator 2'." may catch when the cover is lifted. This causes great diiiculty in removing the inner cover from a stack of coils unless a bumper 3d is employed to contact the inner curves of the corrugated cover and thereby -prevent the individual ribs from extending beyond the line of the inner curves of the corrugations.

The depending skirt 92 of the inner cover l I is preferably formed with the plate 49 into an integral straight angle section, then curved as required, welded to the wall 4 l, then the unnecessary portions of the plate vli) external to the wall 4l are cut out with an Oxy-acetylene torch. When bending this angle structure it is far easier to place the skirt 49 on the inside radius of the wall 4l, 4his also giving a smaller diameter sand seal and less contact surface between the sand and the skirt 49 for the overhead crane to overe come when lifting the inner cover out of the hot sand seal 25.

The separator disclosed has the great advantage of no annular plate to buckle and twist, together with the reduced welding as compared to that required in separators of the prior art. Heat transfer from circulating gases is improved due in part to direct contact between gases in the gas passages and the adjacent upper and lower edges of the strip in the coils and in part to the turbulence at the intersection of the gas streams between ribs 3| and the ribs 32 of opposite planar series. The ribs in these separators must present enough bearing surface to the coils to avoid cutting them and producing stickers which do not properly uncoil after annealing. Higher temperatures may require closer spacing of the ribs than shown in Fig. 2.

The bumper 34 is cut into segments to form a circumferential, discontinuous bumper and allow the coil separator to move freely in thermal expansion and contraction without the restraint of a continuous outer band about the separator.

Every intersection of ribs of opposite series need not be welded where the separators are handled by crane operated magnets rather than hooks or other such xtures.

The foregoing discloses an improved coil separator which is easily fabricated and which avoids troubles encountered by the prior art.

I claim:

A coil separator for separating coils in a stack of coils to be heated, comprising, in combination, two aligned series of curved ribs, each rib in each series defining a generally radial curve of substantially involute shape and extending from an inner circle to an outer circle and spaced from the next adjacent ribs in the same series to form gas passages therebetween from the inner circle to the outer circle, the ribs of one series extending outwardly from said inner circle and generally clockwise and the ribs of the other series extending outwardly from said inner circle and generally counterclockwise, the ribs of one series being curved in a manner to cross ribs of the other series, each rib of one series being joined to ribs of the other series, and the ribs of each series forming respectively top and bottom sides of the separator for engagement with the coiis to be heated.

References Cited in the le of this patent UNITED sTATEs PATENTS Number Name Date 1,896,286 Burns et al. Feb. 7, 1933 1,976,557 Haskell Oct. 9, 1934 2,179,073 Dames Nov. 7, 1939 2,489,012 Dailey, Jr. Nov. 22, 1948 2,607,577 Straub Aug. 19, 1952 FOREIGN PATENTS Number Country Date 218,390 Great Britain July 7, 1924

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