US3415506A - Coil spacer - Google Patents

Description

Dec. 10, 1968 c. c. BLACKMAN COIL SPACER 2 Sheets-Sheet 1 Filed April 6, 1966 Dec. 10, 1968 c. c. BLACKMAN 3,415,506

COIL SPACER Filed April 6, 1966 2 Sheets-Sheet 2 3 33Gb 43b/ INVENTOR. Ca/V/h lgfickmafl United States Patent 3,415,506 COIL SPACER Calvin C. Blackmail, 24272 W. Lake Road, Bay Village, Ohio 44140 Filed Apr. 6, 1966, Scr. No. 540,725 14 Claims. (Cl. 263-47) ABSTRACT OF THE DISCLOSURE A spacer adapted to be placed between coils in an annealing furnace. The spacer has an upper set and a lower set of support plates welded together in superimposed relationship with the plates defining intersecting gas passages, at least some of which in each set extend from the central opening to the periphery.

The present invention relates generally to the art of annealing, and more particularly to a novel spacer to be disposed between end surfaces of coils of metal stock, being annealed in a stacked arrangement end to end, permitting substantial load bearing support and improved convection transfer passages for circulated atmosphere gases.

Metal coils of strip or wire are normally heat treated after cold reduction in cover type furnaces for the purpose of annealing, stress relieving and improving the physical properties of the metal being treated. The present practice with bell type furnaces consists of stacking coils with spacer means, of some type, disposed between adjacent coils to prevent the metal coils sticking together. Heating of the metal is accomplished by radiation from the furnace walls and from radiant heater tubes to a metal bell retort covering the metal coils or directly to the coil outer surface and by a gaseous atmosphere within the bell retort which is circulated by a fan. This circulation is conventially known as forced convection. Many of these spaces are designed to permit a flow of the gaseous heating atmosphere across the metal coil edge by forming passages of various shapes in the spacer. These prior art spacers have the drawback that a minimal convection heat transfer is achieved between the coils and the gases flowing in the passages.

In accordance with the present invention, an improved coil spacer having intersecting primary and auxiliary or or secondary channels is achieved with reduced cost of manufacture by the utilization of standard shapes and construction. The configuration insures a maximum of exposure of coil edges to the atmosphere and increases turbulence of the gases in the channels as well as providing a structurally strong and stable design.

Those skilled in the art will gain a further and better understanding of the present invention from the following detailed description, reference being had to the drawings accompanying and forming a part of this specification in which:

FIGURE 1 is a sectional view somewhat schematic of a furnace and coils with coil spacers disposed between the coils;

FIGURE 2 is a plan view of one embodiment of a coil spacer according to this invention;

FIGURE 3 is a sectional view taken substantially along the plane designated by line 33 of FIGURE 2;

FIGURE 4 is a sectional view taken substantially along the plane designated by line 4-4 of FIGURE 2;

FIGURE 5 is a plan view of a portion of another embodiment of the coil spacer according to this invention;

FIGURE 6 is a plan view of a portion of still another embodiment of a coil spacer according to this invention;

FIGURE 7 is a plan view of a portion of yet another embodiment of a coil spacer according to this invention; and

FIGURE 8 is a plan view of a portion of still another embodiment of a coil spacer according to this invention.

Briefly, this invention contemplates a coil spacer formed from sets of upper and lower plates secured together to form upper and lower primary channels radiating outwardly from a central opening to the outer edge and also upper and lower auxiliary or secondary channels extending from the primary channels to the outer periphery or between primary channels. This configuration is designed to provide maximum exposure of the coil edges and improve the turbulence of the flowing gas to thereby improve heat transfer between the gas and the edges of the coils. The plates are also secured together in such a configuration that rigid structural support is provided to the coils with a minimum of material to thereby save on both weight and cost of the spacer.

More specifically, FIGURE 1 shows a somewhat schematic representation of a bell-type furnace with coils therein separated by convector plates or spacers of this invention. This showing is merely illustrative of one type of conventional furnace in which the spacers of this invention can be utilized. The furnace includes an outer radiant cover 10 and an inner bell shaped retort 12 sealed in a sand seal 14 around the furnace base 16. This seal confines the gaseous atmosphere therein. An impeller 18 is disposed in the base 16 and is driven by a drive unit 20. A stack of coils 22 is disposed within the bell retort 12. A convection spacer 24 according to this invention is interposed between each pair of adjacent coils 22 and between the bottom coil and the base 16. A cover plate 26 is placed over the eye of the upper coil to prevent the flow of gas through the top of the eyes. The spacers 24 have channels (not shown in FIG. 1, but which will be described in detail presently) which allow gas to flow from the outer surface of the spacers to their centers. The impeller 18 is driven in a direction to draw ga through the spacers and down through the eyes of the coils and force the gas up around the outside of the coils as shown by the arrows. Since the spacers 24 have channels from the outer edge to their center, gas will flow through these channels to the eye of the coils and then down and through the impeller 18. This circulation improves the heat transfer between the gas and the coils.

Referring now to FIGURES 2 through 4, one embodi ment of a spacer, or convector according to this invention is shown. The convector has an upper set of plates designated generally as 30a and a lower set of plates designated generally as 30b welded to the upper set 3011. The set of plates 30a has an inner row of plates 32a, two intermediate rows of plates 34a and 36a and an outer row of plates 38a. The plates of the lower set 3017 are identical in shape and arrangement to those in the upper set 30a, and those plates of the upper set are designated by the letter sufiix a and those of the lower set are desig nated by the letter sufiix b. The plates in each row 32a, 34a, 36a and 38a are each arranged in circumferentially spaced relationship with the plates of the various rows being radially spaced from each other. The plates of each of the rows 32b, 34b, 36b and 38b are similarly arranged below those in the upper rows. The plates 32a and 32b of the inner rows, are each provided with arcuate edges 40a and 40b, respectively, part cylindrical in shape which define a central opening 42. The plates 32a, 34a, 36a and 38a define radially extending circumferentially spaced primary channels 440:, and secondary channels 46a, 48a and 50a extending at right angles from one of the primary channels 44a. Similarly the plates 32b, 34b, 36b and 38b define radially extending circumferentially spaced primary channels 44b and secondary channels 46b, 48b and 50b extending at right angles from one of the primary channels 44b. The upper and lower primary channels 44a and 44b are circumferentially offset from each other, and each widens outwardly from the central opening to the outer periphery.

The secondary channels 46a, 46b, 48a and 48b each extend between adjacent primary channels, whereas secondary channels 50a and 501) each extend from a primary channel to the outer periphery of the spacer. It will be seen that each of the secondary channels 46a, 48a, and 50a intercepts one of the primary channels 44b and each of the secondary channels 46b, 48b, and 50b intercepts one of the primary channels 44a. Also, it can be seen that the primary channels 44a and 44b extend radially from the center opening 42 but their center lines do not pass through the center of the opening 42 but rather are off-set therefrom.

The flow of gas through the various channels defined by the upper plates, when the convector is in use is shown in solid line arrows in FIGURE 2 and in the various channels defined by the lower set of plates is shown in broken line arrows. This particular fiow pattern increases turbulence in several ways and thereby increases the efficiency of heat transfer between the gas and the coils. One of the ways that turbulence is increased is by the changing of direction of the gas flow as it flows between the secondary channels and primary channels. Another factor increasing the turbulence of the flow is the interruption of the smooth fiow in the primary channels 46a and 46b by the intercepting thereof by the secondary channels. This provides a rough floor or ceiling which greatly increases the turbulence of the gases as they flow across it. Also, there is increased heat transfer by virtue of the construction of this convector which exposes more area of the coils to the gas than prior art spacers.

Additionally, the structural strength of this spacer is improved over prior art spacers, which improvement is characterized by the elimination of any single plane across the spacer of single plate thickness by providing a truss construction greatly increasing the section modulus in any single plane for bending. This strong construction permits the widening outwardly from the center of the primary channels 44a and 44b to provide an increased area of gas to metal contact.

Referring now to FIGURE 5, another embodiment of this invention is shown. In this embodiment upper and lower rows of plates 130a and 13% are similar in arrangement to those of the previously described embodiment, but the plates have rounded edges where the secondary channels join their respective primary channels 144a and 14417. This will improve gas flow and gas-coil contact area to some extent; however, this construction is somewhat more expensive since extra burning or cutting of plates to give these rounded corners is required. Where costs are justified, however, this is an improved construction.

In the embodiment shown in FIGURE 6, plates 232a, 234a, 236a, 238a, 2321), 234b, 2361) and 238!) are curved to provide curved auxiliary channels 246a, 248a, 250a, 246b, 248b, and 25011. This construction provides a longer path of travel for the gas in the auxiliary channels and hence longer period of contact between the gas and coils to increase the heat transfer. However, this also is a more expensive construction and the extra cost is not normally justified by the relatively small increase in heat transfer characteristics. However, where rapid heat transfer is critical the cost may be justified.

Still another embodiment of a spacer according to this invention is shown in FIGURE 7. In this embodiment the edges of the plates of the sets 330a and 33% forming the primary channels 344a and 3441) are curved and positioned to form curved or convoluted primary channels 344a and 3441). This will provide a longer path of travel for the gas in the channels and hence better heat transfer.

Still another modification of the device of FIGURE 2 is shown in FIGURE 8. In this embodiment the edges of the plates of the sets 430a and 43% which form primary channels 444a and 44411 are staggered or stepped, as opposed to their in line configuration in the embodiment of FIGURE 2. Although the edges of the plates of both sides of the primary channels are shown stepped, it is particularly beneficial that those on the clockwise side of the channels 444a and 444b, as viewed in FIGURE 8, be stepped to increase the air flow from the primary channels 444a and 444i) to the secondary channels 446a, 448a, 446b and 44812. This stepped configuration also increases the turbulence of the gas in the channels. Thus, although the particular stepped configuration shown is the most desirable, it is to be understood that any staggered configuration of the edges is beneficial to increase turbulence and hence heat transfer.

Each of the modifications of the spacer of this invention has been shown separately; however it is to be understood that these modifications can be combined in numerous ways. For example, curved plates with curved edges can be used to provide curved primary as well as curved secondary channels. Many other combinations will be readily apparent to those skilled in the art.

Also, with any of the spacers shown, if they are to be utilized with light gauge coils, annular metal plates can be placed over the top and bottom thereof to provide the necessary support to these thin gauge coils. The heat transfer then will be through these plates to the coil edges.

While several embodiments have been described various changes and modifications may obviously be made without departing from the true spirit and scope of the invention defined in the appended claims:

I claim:

1. A coil spacer adapted to be interposed between a pair of coils in an annealing furnace comprising, upper and lower sets of support plates in superimposed contacting connected relationship, the plates of each set being configured and positioned to define a central opening, a plurality of radially extending spaced primary channels extending from said central opening and at least one secondary channel extending from each primary channel, the primary channels defined by the upper and lower plates being circumferentially oflf-set from each other.

2. The spacer of claim 1, wherein at least one secondary channel extending from each primary channel defined by the upper plates intercepts a primary channel defined by the lower plates and at least one secondary channel extending from each primary channel defined by the lower plates intercepts a primary channel defined by the upper plates.

3. The spacer of claim 1, wherein the secondary channels extend from the primary channels at substantially right angles.

4. The spacer of claim 1, wherein the secondary channels widen at their junction with the primary channels.

5. The spacer of claim 1 wherein each primary channel flares outwardly at the central opening.

6. The spacer of claim 1, wherein the primary channels widen from near the central opening outwardly to the periphery.

7. The spacer of claim 1, wherein said secondary channels are curved.

8. The spacer of claim 1, wherein at least one of said secondary channels from each primary channel extends between two primary channels.

9. The spacer of claim 1, wherein at least one of said secondary channels from each primary channel extends to the outer periphery of the spacer.

10. The spacer of claim 1, wherein the plates of each set define at least two secondary channels extending from each primary channel, at least one of said secondary channels communicating with the next adjacent primary channel of the set.

11. The spacer of claim 10, wherein at least one of said secondary channels from each primary channel extends to the outer periphery of the spacer.

12. The spacer of claim 1, wherein the edges of said plates forming the primary channels are configured and arranged to provide curved primary channels.

13. The spacer of claim 1, wherein the edges of the plates forming at least one side of the primary channels are positioned out of line with each other whereby to increase turbulence.

14. A coil spacer adapted to be interposed between a pair of coils in an annealing furnace comprising, an upper set of support plates and a lower set of support plates, said sets of plates being in superimposed contacting connected relationship, the plates of each set being configured and positioned to define a central opening, said sets of plates being arranged to provide a plurality References Cited UNITED STATES PATENTS 3/1954 Winder 263-47 4/1961 Menough 263-47 HY LAND BIZOT, Primary Examiner.

T. D FENDER, Assistant Examiner.

US. Cl. X.R.

Images