US3321845A - Cooling grates - Google Patents

Description

May 30, 1967 F. J. BORON 3,321,845

COOLING GRATES Filed Oct. '7, 1964 2 Sheets-Sheet l INVENTOR FRANK I BORON ATTORNEYS 2 Sheets-Sheet 2 ATTORNEYS F. J. BORON COOLING GRATES /x, 5. 6 o o o Zf/W mw o o o e o k H C.. VU o o o o o o /v C| o o o o o Z l@ o o o o o o Q0.u /l M 30 Mw o o o o o M, 5 Y M Vw IIIIIIIIIIIIIIII Il United States Patent O 3,321,845 CUULING @RATES Frank J. Boron, Elyria, Ohio, assigner to Abex Corporation, a corporation of Delaware Filed ct. 7, 1964, Ser. No. 402,282 4 Claims. (Cl. 34E- 164) This invention relates to cooling grates for supporting material at a high temperature and more particularly to cooling grates for use in a cooler for moving cement clinkers or the like issuing from a rotary kiln to a position remote from the kiln.

The cooler, to which the present invention is particularly adapted, receives high temperature material directly from a rotary kiln or the like and conveys this hot material for about fty feet or more while allowing the material to cool. The material issuing from the cooler is then of a suiciently low temperature to be handled by a conventional conveyor. The material issuing from the kiln moves downwardly through the cooler over a tier or series of descending grates. The series of grates are composed of alternatively movable and fixed grates. Each of the movable grates reciprocates to tumble the bed of material downwardly by agitation to the grate next therebelow. In this manner the individual particles are slowly advanced downwardly and horizontally over the series of grates to the discharge end of the cooler.

Each of the cooling grates has a plurality of apertures therein through which cooling air enters from the underside of the grates to cool the material resting on the upper side of the grates. In a conventional and prior art cooler, over which the present invention is an improvement, the grates were connected to a supporting frame by a plurality of bolts having a T-head disposed between a pair of fingers integrally formed on the underside of the grate. The T-bolt was disposed at an oblique angle to the grate and was fitted into an inclined embossure or pad formed on a supporting framework. By tightening the bolts, stop lugs on the grates or the fingers themselves are tightened snugly against the supporting framework so that the grates reciprocate with the supporting framework.

The cooling grates are arranged in overlapping relation with one another. That is, the rear portion of each of the grates is disposed beneath its upper, adjacent grate. Thus, the rear portions of the cooling grates are not in contact with the high temperature material when protected by the upper, adjacent cooling grate in its overlapping position. Because of this overlapping orientation of the grates, there is a difference in temperature between the forward portion of the grate bearing the hot material and the rearward portion of the plate which is not bearing the hot material. This temperature differential causes ther-mal stressing of the plates and this stressing is substantially greatest at the area of connection by the T-bolt. The thermal stressing in this area causes cracking either of the stop-lugs or the fingers and such losses cause premature failure of the grate. While it would be expected that the major problem with the cooling grates would be high temperature wear, it has been found that a more important problem is that of premature failure of the grates because of cracking or breaking of fingers, stoplugs or the grates at this area between the front and rear portions of the plate. Accordingly, an object of the present invention is to alleviate thermal stressing and cracking of grate assemblies in coolers between the front and rear portions thereof by dividing the grates into two portions or sections with an air space therebetween through which thermal stresses cannot be transmitted.

The prior art T-bolt connection between the grate support and the fingers of the grate is unsatisfactory in that the amount of tightening force varies considerably when the grate expands 'by coming up to its working temperature, while the bolt remains at a lesser temperature because it is cooled directly by the air. Accordingly, another object of the invention is to secure the grate assembly to the supporting beam by a nut and bolt wherein the bolt is substantially protected from contact with the cooling air to reduce the temperature differential Ibetween the bolt and the plates supported thereby.

A, more specific object of the invention is the securing of a grate assembly having a grate section with an over lapping lower portion seated in 4a bracket secured to the support beam so that a bolt extending through said overlapping grate sections and the bracket is generally protected from being cooled by the air to a greater extent than the grate sections.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show a preferred embodiment of the present invention and the principles thereof and what is now considered to be the best mode contemplated for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

FIG. l is a section view of a cooler having a series of overlapping and descending grate assemblies constructed in accordance with the preferred embodiment of the invention;

FIG. 2 is an enlarged section of la pair of grate sections disposed in overlapping relationship in accordance with the preferred embodiment of the invention;

FIG. 3 is a bottom view taken along the lines 3-3 of FIG. 2 showing the grate assembly;

FIG. 4 is a plan view of the supporting frame structure for the grate assemblies of the present invention;

FIG. 5 is a sectional view taken along the lines 5 5 of FIG. 4 showing the grate assembly secured by a nut and bolt fastener to the supporting bea-m;

FIG. 6 is a sectional view showing the bracket fastened to the supporting beam of FIG. 5;

FIG. 7 is an elevational view of a bolt; and

FIG. 8 is a plan view of the head of the bolt shown in FIG. 7.

The grate assembly of the present invention is particularly adapted for use in the cooler of the kind illustrated and described in U.S. Patent No. 2,431,799, in which patent there is described movable or reciprocal grates 61 provided with inwardly formed and downwardly extending fingers 63 to receive T-bolts 64 to be tightened by nut 65 against a transverse support member or beam 56. Because the present invention is directed to only the -cooling grates and their manner of attachment to a. similar supporting framework, only a brief description of the cooler is set forth hereinafter.

As best seen in FIG. 5 of the present disclosure, the present invention is characterized by a grate assembly 10 having overlapping grate sections 11 and 12 secured together at the overlapping portions by a bolt. and nut eX- tending through aligned apertures in the grate sections 11 and 12, and in a bracket 16 secured to the support beam 56. A comparison of FIG. 5 of the present disclosure and FIG. 5 of the patent, reveals that the bolt 1d and bracket 16 replace the fingers 63 and T-bolt 64 of the prior art device and that the two-piece grate assembly 10 replaces the grate 61 of the prior art device.

As hereinbefore explained, the hot material issuing from a rotary kiln is discharged on to the upper surface of the upper most grate assembly 10. In FIG. l, the upper most grate assembly is a fixed or non-movable grate assembly The movable grate assemblies 10 are alternatively spaced between fixed grate assemblies 10.

The supporting beams S6 for the movable grate assemblies 111 are adapted to be reciprocated to move the grate assemblies 10 in the ohrizontal plane and thereby move the front hooked end portions of the movable grate assemblies 10 rightwardly, as viewed in FIG. l, to push and tumble the material horizontally, that is rightwardly, and downwardly. During the reverse reciprocatory movement ot the left, the hooked portions 21 of the xed grate assemblies scrape some material from the outer hooked ends 20 of the movable grate 1t) so that material falls or tumbles to the ixed grate assembly immediately therebelow. The amount of reciprocatory movement of the grate assemblies 10 and the rate of reciprocation will vary depending on the temperature of the material and the thickness ofthe layer of material being moved by the grates.

Preferably, the fixed and movable grate assemblies are substantially similar in construction and are formed from a suitable cast-iron or steel selected for its ability to resist high temperature wear. Each of the grate sections 11 and 12 is provided with a series of rows of air holes or apertures 25 through which air is blown to impinge against the material disposed on the top surface 28 of the respective grate sections 11 and 12. As will be readily appreciated, the forward grate section 12 has a greater extent of its upper surface 28 covered with the hot clinker material and for a longer period of time than the top surface 28 of the rear grate section 11. This is because the rearward grate section 11, particularly when in its leftward position, as seen in FIG. l, is disposed and protected by its next above grate assembly 11i while its own forward grate section 12 will have the hot material resting thereon. In the one-piece cooling plates of the prior art, such difference in temperature causes thermal stresses between the front and rear sections of the `cooling grate assemblies; and it is this thermal stressing, which has caused cracks and premature failure of these grates of the prior art.

For the purpose of alleviating the condition of thermal stressing between the front portion and the rear portion of a cooling grate, the present invention employs separate grate sections 11 and 12, which are abutted against one another at abutting faces 30. The air space at the abutting faces 30 of the grate sections 11 and 12 prevents the transmission of thermal stresses due to ternperature differentials of the front grate section of 12 and the rear grate section 11 thereby avoiding the problem of cracking due to thermal stressing in the area of the parting line 30.

As best seen in FIG. 2, the grate sections 11 and 12 have overlapping portions 31 and 32. The overlapping portion 32 of the front grate section 12 includes a downwardly and rearwardly extending substantially L-shaped flange terminating in a rearward end wall 34. As best seen in FIG. 3, the flange 32 extends only partially of the length of the grate sections 11 and 12 and terminates in side walls 35 and 36, which are spaced inwardly of the side walls 38 and 39 of the sections 11 and 12.

The overlapping portions 31 and 32 of the grate sections 11 and 12 have openings 40 and 41 therein, which are adapted to be aligned to receive a fastening bolt 44, FIG. 7. The bolt 14 has a square head 45 which is adapted to t ush with the top surface 28 of the grate sections 11 and 12, when fully seated in the aperture 40 in the grate section 11. The bolt 14 is threaded at tis lower end and is adapted to have its lower threaded end inserted through Yan aligned opening 48 in a horizontal web 49 of the bracket 16, FIG. 6, to receive a tightening nut 50. Tightening of the nut on the bolt 14 clamps the grate sections 11 and 12 together and to the bracket 16 and beam 56.

Preferably, the bracket 16 is secured by welding to the beam 56. Also it is preferred that the bracket 16 and an upstanding flange 52 form a trough 53, FIG. 6, be-

tween the beam 56 and the ange 52 of sufficient dimensions to receive the overlapping portion 32 of the grate 12. Thus, when assembled, a grate assembly 10 will be positioned in the manned shown in FIG. 5 with the overlapping portion 32 disposed in the trough between the upstanding ange 52 of the bracket 16 and the beam 56. It should be noted that only the lower end or tip of the bolt 14 is exposed to the cooling air and the remainder of the bolt 14 is protected from the cooling air and will receive generally the same amount of expansion as the overlapping portions 31 and 32. Thus, the bolt 14 does not undergo a significant change in length with respect to the grate assemblyas with the prior art bolt with the T-head with a resultant significant change its holding force. As is best apparent from FIGS. 4 and 5, the skeletal framework for supporting the grate assemblies has a pair of transverse support members S6 and 57, member 57 being parallel to movable support member 56. Stiifening members 58 extend between the transverse support members S6 and 57 and exten-d forwardly in cantilever fashion. The stiffening members have nose portions S9 adapted to be disposed within the hooked ends 20 of the grate section 12. v

The supporting framework includes a plurality of small pads secured at suitable intervals at the top of the support members 56, S7 and 58 to space the greater portion of the undersurface of the grate assemblies 10 from the supporting framework or skeleton, so that air can be circulated between support members and the grate assemblies. Such spacing permits the air to cool practically the entire undersurface of the grates even at the area of the supporting beams, thus, permitting a more or less uniform temperature over the entire grate even at the edges of the grate. As to the manner in which reciprocation of the framework is accomplished, reference may be had to U.S. Patent No. 2,431,799. As readily apparent from FIG. 4, each level of the series of cooling grate assemblies 10 is composed of grate assemblies disposed side by side longitudinally with their respective side walls 28 and 39 positioned on a common support member 58. The number of grate assemblies on each level is determined by the size of the kiln from which the cooler receives its material.

From the foregoing, it will be seen that the present invention is directed to a grate assembly in which the cracking of the grate due to thermal stresses has been alleviated by forming the grate into separate sections having overlapping portions to eliminate the thermal stresses of the grate between its front and rear portions. Also the grate sections are secured to the movable support frame by a novel connection in which the bolt is substantially protected from the cooling air so that the bolt expands and contracts in a more like manner with the grates.

Hence, while preferred embodiments of the invention have been described and illustrated, it is to be understood that they are capable of variation and modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview' of the following claims.

I claim:

1. In a cooler for cooling material while transferring material down a series of descending grate assemblies arranged in overlapping relationship, and having movable grate assemblies alternating with fixed grate assemblies, a movable skeletal grate supporting means having spaced members for supporting and reciprocating said movable grate assemblies, said movable grate assemblies each having a pair of grate sections, said grate sections having overlapping portions with apertures therein, bracket means on said supporting means disposed beneath said overlapping portions and having apertures therein, and fastener means inserted through said apertures in said overlapping portions of said grate sections and through said aperture in said bracket means to fasten said grate assembly to said supporting means.

2. In a cooler for cooling material while transferring material down a series of ldescending grate assemblies arranged in overlapping relationship, fixed grate assemblies, movable grate assemblies alternatively spaced with said Xed grate assemblies, a skeletal grate supporting means having spaced members for supporting said grate assemblies, at least said movable grate assemblies each having a pair of grate sections, said grate sections having overlapping portions with fastener receivingy apertures therein, bracket means on said supporting means disposed beneath said overlapping portions of said grate sections, said bracket means having an aperture therein; and fastener means inserted through said apertures in said overlapping portions of said grate sections and through said aperture in said bracket to fasten said grate assembly to said supporting means.

3. In a cooler, for cooling material while transferring material down a series of descending grate assemblies arranged in overlapping relationship, fixed grate assem blies having a plurality of openings therein through which cooling air moves, movable grate assemblies alternating with said fixed grate assemblies and having a plurality of openings therein through which cooling air moves, a skeletal grate supporting means having spaced members for supporting said grates, at least said movable grate assemblies each having a pair of separate grate sections, said grate sections having overlapping portions with fastener receiving apertures therein, bracket means on said supporting means engaging and supporting said overlapping portions, said bracket means having apertures therein, a fastening bolt inserted through said apertures in said overlapping portions of said grate sections and through said aperture, the shank of said bolt being protected from the cooling air by said overlapping portions and said bracket means, and a nut threaded on said bolt to fasten said grate assemblies to said supporting means.

At. In a cooler apparatus for cooling hot material by cooling air while transporting said material down and across a series of grate assemblies, each having a plurality of openings through which cooling air entering from beneath said grate assemblies to cool said hot material adapted to be disposed on the upper surface of said grate assemblies, a frame means for supporting said grate assemblies in a descending and seriatim manner, each of said grate assemblies being comprised of a forward grate section and a rearward grate section, said forward grate sections adapted to overlie a portion of said grate assembly disposed therebelow, said frame means having a reciprocal skeletal framework adapted to be reciprocated, alternate ones of said grate assemblies being secured to said skeletal framework for reciprocation with said framework to tumble said hot material down and across said grate assemblies, said rearward and forward grate sections having vertically overlapping portions, bracket means secured to said framework and having a trough portion to receive the lowermost of the overlapping portions to support said overlapping portions and said grate sections, and a bolt fastener means having a bolt inserted through said overlapping portions and through an aperture in said bracket means and having a nut threaded thereon so that the shank of the bolt is protected from said cooling air.

References Cited UNITED STATES PATENTS 1,662,708 3/1928 Jones l26-167 1,798,019 3/1931 Harrison 110--32 2,431,799 12/1947 Gaffney 34-164 2,971,508 2/1961 Rivers 11G-*38 X 3,010,218 11/1961 SylVeSt 34--164 3,126,846 3/1964 Wagner 110-38 FREDERICK L. MATTESON, IR., Primary Examiner. C. R. REMKE, Assistant Examiner.

Claims (1)

1. IN A COOLER FOR COOLING MATERIAL WHILE TRANSFERRING MATERIAL DOWN A SERIES OF DESCENDING GRATE ASSEMBLIES ARRANGED IN OVERLAPPING RELATIONSHIP, AND HAVING MOVABLE GRATE ASSEMBLIES ALTERNATING WITH FIXED GRATE ASSEMBLIES, A MOVABLE SKELETAL GRATE SUPPORTING MEANS HAVING SPACED MEMBERS FOR SUPPORTING AND RECIPROCATING SAID MOVABLE GRATE ASSEMBLIES, SAID MOVABLE GRATE ASSEMBLIES EACH HAVING A PAIR OF GRATE SECTIONS, SAID GRATE SECTIONS HAVING OVERLAPPING PORTIONS WITH APERTURES THEREIN, BRACKET MEANS ON SAID SUPPORTING MEANS DISPOSED BENEATH SAID OVERLAPPING PORTIONS AND HAVING APERTURES THEREIN,AND FASTENER MEANS INSERTED THROUGH SAID APERTURES IN SAID OVERLAPPING PORTIONS OF SAID GRATE SECTIONS AND THROUGH SAID APERTURE IN SAID BRACKET MEANS TO FASTEN SAID GRATE ASSEMBLY TO SAID SUPPORTING MEANS.

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