AU456552B2

AU456552B2 - Improved chainlink assembly for grate conveyor

Info

Publication number: AU456552B2
Application number: AU46117/72A
Authority: AU
Inventors: John Hartwig Walter
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1971-09-01
Filing date: 1972-08-30
Publication date: 1974-12-19
Also published as: US3735858A; DE2243154B2; AR196080A1; GB1374904A; JPS549393B2; NO138842C; SE390284B; CA956256A; ES406257A1; JPS4835574A; AU4611772A; DE2243154A1; NO138842B

Description

46.11 7M7 This invention isconcerned with an improved chain linkc assembly for forming part of a grate conveyor. The invention will be described as embodied in a travelling grate conveyor associated with a G-rate-Kiln system, as-now known in the art, in which the travelling grate carries load material such as pelletized ore through a drying zone or zones and a preheating zone or zones before discharging the load material into a rotary kiln. The load material carried by the conveyor may be at a temperature in the range of from 600 to 2100 for example, depending upon the zone in which the temperature is measured and also depending. on the location at which the temperature reading is taken depthwise of the bed of material on the grate conveyor. In the prior art relati.ng to grate conveyors for use with Grate-Kiln systems, the pivotally connected links of the conveyor chains to which the grate members are connected are conventionally made of one-piece metal castings each comprising a main link body formed to provide a pair of laterally spaced chain bar sides formed at one of its ends to define a yoke portion, the chain bar sides merging at their opposite ends to define a neck portion, and also including an integrally cast thin -Wall arched cover member, the yoke portion and the neck portion each being bored to receive a pivot member for connecting the link body at each end to other contiguous link bodies. The structure Just described is one link in the prior art. cbiain, and it will be understood that a plurality of such links are pivotally connected to each other with the neck portion of one chain link being received within the yoke portion of the next succeeding contifjuo4s chain link. The

2 6,552 ~45

46.11 7n7 links are known in irality of pivotally connected chain The term "chain link proper" e art as a "chain strand". and claims is hereby used throughout the Specification as hereinbefore described fined as the main link body formed

t exclusive of the cover. of the prior In the one-piece chain link construction serious problems arise -tas just briefly described, several to overcome. tich it is an object of this invention of the prior art one- One of the most serious problems a Grate-Kiln conveyor system Lece chain construction used in the chain link proper of the 9 that the chain bar sides of not only operate at a high rior art one-piece construction thereof contiguous the emperature at least in the portion are subjected to large ntegral cover member but also the portion of each emperature differentials between is contiguous or close to espective chain bar side which portion of the respective he integral cover member and the the integral cover member. ain bar side which is remote from a thermal stress in the !histemperature differential causes to the chain pull tensile hain link proper which is additive proper is also subjected. Atress to which the chain link tensile stress are factors rhis combined thermal stress and link proper and subject it which weaken the prior art chain topossible mechanical damage. and thermal The undesirable high operating temperature the prior art chain link stress in the chain bar sides of that the prior art chain proper are largely due to the fact with the "chain link link cover member is integrally formed the heat from the proper" as a unitary casting whereby portion is readily higher temperature integral cover conduction to the chain transferred principally by thermal

3- 456,552 bar sides of the "Ichain link proje~~4j 77 flue to the time factor involved in the movement of the grate conveyor through the heated zone or zones, (a relatively short period of time) and thence into a lower temperature region of atmospheric temperature, the temperature in the various portions of each chain bar side of the prior art one- piece chain link does not have time to equalize, despite the transfer of heat by thermal conduction in the one-piece chain link, thereby producing the temperature differential and resulting thermal stress just described. The present invention sets out to solIve the problem of the thermal stress in the prior art chain link proper due to the temperature differential betweean the portion of the chain link proper close to the integral cover and the portion of the chain link proper remote from the integral cover by providing a construction in which the cover member is not integral with the chain link proper but is a separate member pivoted to the chain link proper to serve as a heat shield 'which covers the entire chain link proper and shields the chain link proper from heat radiation from the pellets carried by the conveyor. Also, by having the cover member made as a separate member which is not integral with the chain link proper, thermal conduction from the cover member to the chain link proper is significantly reduced-as compared to the prior art one-piece construction. Whilst in the improved construction of chain link, heat from the pellet bed can transfer by radiation from the pellets to the -non-integral cover and by radiation from the non- integral cover to the chain link proper, and also while heat is transferred to the chain link proper by convection gases passing through the slotted cover of the improved chain link assembly, the net result of the various factors described is that at given temperature conditions

4 5'6,552

46.117/72 to which the grate conveyor may be subjected, the chain

link proper of the improved construction of the present

invention operates not only at a lower temperature but

also at a more uniform temperature throughout the body

thereof than the chain link proper of the one-piece

chain link construction of the prior art, thereby

substantially eliminating any thermal stresses in the

chain link proper and permitting the chain link proper of

the construction of the present invention to have greater

mechanical strength and stability than the chain link

proper of the one-piece chain link construction of the

prior art.

Another serious problem of the prior art one-piece

chain construction used in a Grate-Kiln system is that

because of thermal considerations and stresses caused by

the temperature differential between the higher operating

temperature of the arched integral cover portion and the

lower operating temperature of the remaining structure or

"chain link proper" of the chain link of the prior art

one-piece construction, it is impractical to provide a

substantial number of gas passage slots in the integral

arched chain link cover member of the prior art one-piece

construction since the temperature.differential between

the "chain link proper" and the integral arched chain link

cover member would cause a buckling of the one-piece chain

unit if such plurality of slots were provided in the integral

arched cover member.

For the reason just riven, to the best of our knowledge

it has hot been known to provide cover members in the

one-piece chain link construction of the prior art having

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46,11772 more than a minimum number of slots therein such as one slot, for example). As a result of the la2ck of a substantial number of slots in the integral cover portion of the prior art one-piece construction, the pellet load or other load material being carried through the heat treatment zone or zones by the grate conveyor has been improperly treated in the regions where the pellet load Gr tho liko overlies the substantially unslotted one-piece chain link of the prior art, since the unslotted construction just referred to substantially inhibits or prevents thc passage of hot gases through the chain link cover, with the result that the pellet load overlying the prior art chain link cover is untreated and turns into dust. Thus, in substance, it might be said that in using the integral substantially unslotted cover members of the prior art chain link construction thia. each chain strand is a "potential ribbon of dust." In contrast to the prior art one-piece chain link, the tw-plee chain linkkof the present invention permits the use of a substantial number of gas passage slots or apertures in the cover member, thereby permitting better heat treatment of the material overlying the chain strand, such as a bed of mineral ore pellets. Another problem inherent in the one-piece chain link

construction of the prior art is the fact that since the cover member is formed integrally with the "chain link- proper", it is subject to the mechanical pulling tensions applied to the chain during the normal movement of the grate conveyor. The chain link cover member operates at a substantially higher temperature than inost of the"chain link proper." Since the integral arched. cover member of the prior art chain link is

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46,117/

operating at an subjected to the chain pull tensile stress and is frequently elevated temperature, the combination of these factors one-piece contributes to the mechanical failure of the prior art which the chain link when the yield stress of the material of

one-piece chain link is made is exceeded at a given temperature

of the material and tensile stress thereon. of An important advantage of the chain link construction member is the present invention is that the non-integral cover tension not subjected to the tensile stresses of the mechanical a high tempe- of the pull on the chain, and hence can operate at

rature without danger of mechanical failure. In the construc- of the pull tion of the present invention, the mechanical tension and, due to on the chain is carried by the "chain link proper" by the the "heat shield" effect provided in the new construction proper", non-integral cover member relative to the "chain link new construc- mentioned previously, the chain link proper of the for a given tion operates at a lower and more uniform temperature of the prior operating condition than does the chain link proper art one-piece construction. and the Thus, both the separate non-integral cover member subject to chain link proper of the present invention are less chain link mechanical failure than the integral cover member and proper of the prior art construction. to pro- It is, therefore, an object of the present invention in heat treat- vide a chain link assembly for a grate conveyor used with the one- ment processes which overcomes problems associated the mecha- piece chain link member of the prior art, and improves nical strength of the chain link

456,552 assembly. 4611 It is a still further object of the invention to provide such a chain link assembly for a grate conveyor in which the non-integral cover member of the chain link serves principally as a load support, heat shield for the "chain link proper" as herein defined, and gas passage grid, and is not subjected to chain pull tensile stresses, whilst greatly reducing thermal stresses in the chain link proper with resulting greater mechanical strength in the chain link proper.

In achievement of these objectives, there is provided in accordance with the invention, a chain link assembly

arranged to be pivotally connected by pivot members to:

adjacent chain link assemblies to form part of a grate

conveyor, the chain link assembly comprising a chain link proper as hereinbefore defined, and a non-integral and separate cover member serving as a heat shield which

covers.the entire chain link proper and is pivotally

connected at one end thereof to the chain link proper so

as to be in relatively low heat-conduction relation thereto

and has limited pivoted movement relative to the chain link

proper.

Preferably the cover member is pivotally connected at said one end thereof to the chain link proper so as

to pivot about an axis which is coaxial with the axis of

the respective pivot member at said one end of the chain

link proper.

8- 456.552

46,117/72 Preferably said cover member includes a lip portion extending x4ending from one end thereof and a tail portion pivotally rom the opposite end thereof, the lip portion being an axis onnected to the chain link proper to pivot about tail portion o-axial with that of the pivot member, and the member of )eing received in underlying relation to the cover m adjacent chain link assembly. of lip Preferably said cover member includes a pair portions portions extending from one end thereof,. said lip cover member, being spaced from each other laterally of the between the tail portion of one cover member being received installed the lip portions of an adjacent cover 'memberwhen in the chain link assembly. Preferably the cover member has gas passages theretbrough to define a gas passage grid. is The -invention will now be described in detail and drawings illustrated, by way of example, in the accompanying in which:- Figure 1 is a top plan view of a grate conveyor including the chain construction of the invention; Il-II Figure 2 is a view in transverse section along line of Figure 1; Figure 3 is a view in longitudinal section taken along the grates line III-III of Figure 1 showing details of one of which are moved by the conveyor chains of the invention; Figure 4 is a top plan view of one "chain link proper" link Figure 5 is a view in side elevation of the "chain proper" of Figure 4; Figure 6 is a view in transverse cross-section along

9 456.5 52

6.11 7 2 4. line VI-VI of Figure 4;

Figure 7 is an exploded isometric view showing two

"chain link proper" units connected in pivotal relation

to each other, and also including a oha4-link cover)

adapted to cover one "chain link proper" unit;

Figure 8 is a top plan view of the cover member of

one chain link assembly;

Figure 9 is a bottom plan view of the cover member

of Figure 8;

Figure 10 is a view in transverse cross-section

along line X-X of Figure 11 showing the cover member

assembled with respect to an underlying chain link proper; and

Figure 11 is a view in side elevation of the assembly of

Figure

Referring to the drawings, and more particularly

to Figure 1, there is shown a grate conveyor generally indicated

at 10 which moves in the direction shown by the arrow in Figure 1

and which includes a plurality of grate members such as 12A, 12B,

456,552

46,11 7/7 S12A', 12B', 12C', inclusive. It will be understood that

y a portion of the total conveyor length and width is shown the view of Fig. 1. The grates shown in the view of Fig. 1

arranged in transverse rows such as the row including grates

12B and 12C; and another row including grates 12A', 12B'

S12C', etc. Each transverse row of grates is connected

ween a pair of chain strands generally indicated at 14A and

1, respectively. Each of the chain strands 14A and 14B is

-med of a plurality of connected two-piece chain links or chain

ik assemblies generally indicated at 16 which form the subject

:ter of this invention.

The grate conveyor 10 has particular utility for con-

ing material being processed, such as mineral ore in the form pellets or compacts, through a drying zone or zones and a pre-

iting zone or zones before discharging the load material into

cotary kiln. In passing through the various drying and/or

heating zones, the load material on the conveyor (Fig. 2) is

bjected to updraft or downdraft currents of heated gas or air Lch pass through the load material and through the slotted

aveyor grates and, in the case of the present invention, through a slots in the cover members of the chain link assemblies, to described hereinafter. Conveyor chain strands 14A and 14B

e trained at the opposite ends of the run thereof around

rocket members or the like. Conveyor chain strands 14A and

B are supported intermediate the length thereof by support llers such as those indicated at 27 mounted on shaft 29 (Fig. 2).

As best seen in the views of Figs. 1, 2 and 3, each

the grate members or castings such as 12A, 12B, etc., made

cast iron or other suitable material, includes a head portion .hich loads in th dirac'tion of tra"' of hi r and a

in body or tail portion 20 which trail in the diroction of 11. 456.552

46.11717i tr'o.. .f the pn. oyo The grate member such as 12A also includes an intermediate leg portion 22 located intermediate the head por- tion 18 and the tail portion 20 of the grate 12A. The under sur- face of head portion 18 of the grate is formed with an arcuate bearing surface 24 which is adapted to pivotally mount the grate on a pivotal support means in the form of a pipelike support such as a "pipe spacer" 26 or the like. In the illustrated embodiment, a given pipe spacer 26 extends for the entire transverse width of three grates such as 12A, 12B and 12C. Pipe spacer 26 is supported at the opposite ends thereof by chain pins 49 carried by the chain members 16 of the two chain strands 14A and 14B, respectively. Pipe spacer 26 is coaxial with chain pins 49. It will be noted in the view of Fig. 3 that the main body portion or tail portion of the grate 12A extends in a generally horizontal plane and rests at its trailing extremity on the head portion of the con- tiguous trailing grate member 12A'.. The grate member such as 12A is secured in position about the pivotal support 26 by a grate clip 28 which in turn is secured to the lower end with respect to view-of Fig. 3. of inter- mediate leg member 22 by suitable fastening means 30. The pivotal connection of the respective grates to the pivotal support 26 accommodates any necessary pivotal movement of the grates as, for example, when the conveyor moves from the upper to the lower

pass thereof. The grate members, such as 12A, per se form no part of this invention but have been described merely in order to properly -orient-and relate them to conveyor 10 and to the t chain link assemblies forming part of conveyor

Referring now to Figs. 4, 5 and 6, there is shown one unit of what is herein referred to as the "chain link proper" as m 1' coftr momber for the t;-o-piece chain link .which will be described hereinafter in more detail.

-12 456.552

46,117P2 'he chain link proper generally indicated at 36 is a casting of and includes isuitable metal such as an alloy steel, or-the-4 ke other and ipair of side bar members laterally spaced from each

Lndicated at 38. Side bar members 38 define the yoke portion

f the chain link proper. The two side bar members 38 converge proper. together to form the neck portion -42 of the chain link with rhe yoke portion 40 of the chain link proper is provided neck portion bearing passages 44 therethrough, and similarly, the passage 46 42 of the chain link proper is provided with a bearing chain link therethrough. As will be seen in Fig. 7, when the together, the proper 36 and chain link proper 36' are assembled yoke neck portion 42' of the member 36' is received within the the yoke portion 40 of member 36, with the bearing passages 44 of

member 36 being aligned with the bearing passage 46' of the in member 36' so that a chain pin 49, shown in dotted outline passages of the Fig. 7, can be received in the aligned bearing two members 36 and 36' to provide a pivotal connection between

chain link proper 36 and chain link proper 36'. Chain pin 49

lies along a substantially horizontal axis.

Referring now to Figs. 7-11, inclusive, the cover.

member for the -twopiG-e chain construction is generally indicated metal at 50 and includes a main body portion 52, of a suitable

such as low carbon steel the lik. and of greater lateral width shown than the lateral width of the underlying chain link proper

in Figs. 4-6 inclusive. As best seen in Figs. 2 and 10, the surface under surface of the cover member 50 rests on the upper

of the underlying chain link proper 36 (as viewed in the upper

or working run of the grate conveyor). (The "lateral width" of in the chain link cover member is the left-to-right dimension

the views of Figs. 1, 2 and 10.) Thus, as best seen in the

transverse cross sectional views of Figs. 2 and 10 of. the drawings,

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46.117/72 the cover member 50 is of sufficiently greater transverse width than the transverse dimension of the underlying chain link prope 36 that the cover member projects laterally on either lateral siq of the underlying chain link proper 36 with which the cover member is assembled as will be explained hereinafter. The upper surface of the chain link cover member as viewed in Figs. 1, 2, 8, 10 and 11 has a slight convex arcuate curvature in its longiti 4 dinal dimension (lengthwise of the conveyor). th e Cvver m-e-mber

reaching itc eonexyity intermediate -he length o0f he eflvpr ipmhr n-a 44i m 4 p ,m.um convexity in tho end rogionE whor"' Thay-DrtnQ (to h c ta.4 po.irt n go (t be deeribed) r lc at The main body .portion 52 of the cover member is provided with a gas passage grid in the form of a plurality of elativbely narrow slotted passages therethrough generally indicated at.54 which permit the passage of gases therethrough. In the embodiment illustrated in the drawings, thirteen such slotted passages 54 are provided and extend in a longitudinal direction relative to the lengthwise direction of travel of the chain. The passages 54 extend for a substantial part of the length of the main body portion 52 of the cover member 50. Slotted passages are sufficiently narrow (for example 1/4 inch in lateral width) to prevent any significant passage therethrough of the load material carried by the upper surface of cover member 50, but yet to permit substantially unrestricted passage therethrough of hot gases to the load material. At the leading end of the chain link cover member relative to the direction of travel of the conveyor chain, the cover member is centrally recessed as indicated at 56 to define two extensions or lips each indicated at 58 which in effect form extensions of main body portion 52. The body portion 52 of cover member 50 is also provided with a trailing extension or

14 456,552 which is centrfAcatd t mp t th transverse or lateral dimension of cover meme 0 ThE Matevit dimension of the tail portion 60 of cover memb~er 50) Is ffS4qtt:l). less than the corresponding lateral dimaasl=amf tke rcsM 560' whereby the tail portion 60 of one covrmme Wi dpe C be received in and freely movable withis Ufits reatiEve tv the recess 56 of the trailing cover member 5801 as 1-1 fm the views of Figs. 1 and 11. The longItSfial dofsfmC tail portion 60 of the cover member Is Mczsner tfaw tMe t~ dimension of recess 56, whereby when taijil p~tSeW= E the one cover member 50 is received in recess 56 of tthe tntm me membr 50', the trailing end portiom-af tMe tail F )6MoS one cover member 50 is adapted to ulndbLfe auffl t~a3ln the edge 57 of recess 56 of the trailingi) ve uho So 6",M seen in the view of Fig. 11, along the entfr VMat Ccf of the grate conveyor whereby to maiintaft awr gftam cae in interfitted assembled but relatIvelp mm~ llf-i the contiguous cover member thruamt the eut~ram Rafft ofE movement of the grate conveyor. As best seen in the views, of VIg~.. 9) onil IM., thke surface of the laterally outer portiom of oeaE thespe 06 body projections or lips 58 is provided uift a we patiun o= rib 63 having an arcuate bearing surface wfai~ Is fadMtb

*rest in. bearing relation on the peripheil 4 Mz aEo the VD~

support means or pipe spacer 26 laterally aywmf of teunzrdr- lying chain link proper. The under sinrfa~e of ead of the b=dT'

projdctions 58 is also provided with a bvazWm&UeOM

extending .(relative to the view of FP19- IRV) leg pmmtfan 16 sftioh

is adapted to serve as a mounting means f=r a bow8)f

which includes an arcuate bearing parimo W 7T) p to) UEZVOWie

the pipe spacer 26. A suitable fa-teing meanw, 72 sudii as ai

t5

46.117 2 relative to leg the-lhe secures retainer bar 68 in position that when retainer bar 68 member 66. It can be seen, therefore, of Fig. 11, and with is mounted on leg 66 as shown in the view 63 of body projection the arcuate bearing portion 64 of wet portion surface of the pipe or lip 58 resting on an oppositely disposed supported on pipe spacer spacer, that cover member 50 is pivotally the under surface of 26 by the bearing arrangement provided on 58 of a given cover member the oppositely disposed body projections projection 58 and The fit of the bearing portion 64 of body spacer 26 are such as to of the retainer bar 68 relative to pipe any necessary relative provide a pivotal connection which permits 52 and pipe- spacer pivotal movement of chain link cover member for example, when the 26 with respect to each other as may occur, or the like, or during conveyor chain moves around an end sprocket the return run of the grate conveyor. transverse of the Pipe spacer 26 lies.on the same axis pins 49 on which the neck path of conveyor travel as do the chain is pivotally connected to portion of -a given chain link proper link prope;. The chain the yoke portion of a contiguous chain pipe spacers 26 to pins 49 extend into the ends of the hollow 49 being coaxial with the support the pipe spacers 26, chain pins respective pipe spacers 26. 50 on pipe Instead of pivotally mounting cover member 50 may instead spacers 26, as just described, the cover member of chain pins 49 be pivotally mounted directly on the ends proper 36. Also, where a laterally outwardly of the chain link at the left-hand side edge of pipe spacer is not available, as an adaptor or bushing of the the conveyor, as viewed in Fig. 1, may be mounted on the same outer diameter as pipe spacer 26 for cover member chain pin to provide a pivotal support

16 456,552

46.11772 The arcuate bearing portion 64, the leg-66, and the retainer bar 68 beneath each projection or lip 58 of a given cover member are all so located as to lie laterally outwardly of the contiguous surface of the yoke portion of the associated or corresponding chain link proper. Also, as can best be seen in the view of Fig. 11, the tail portion 60 of each cover member 50 is at all times during the operation of the conveyor retained in position by the under- lying and trailing relation of the trailing end of tail portion of one cover member 50 relative to edge 57 bounding recess 56 of the trailing cover member 50' (Fig. 11). The tail portion of a given cover member 50, as best seen in the view of Fig. 11, extends in substantially a downward arc relative to the view of Fig. 11 so that the plane of the trailing end of tail portion lies below the plane of the main body portion 52 of the trailing cover member 50'and also lies beneath and in trailing relation to the leading edge 57 of the main body portion 52 of the trailing cover member 50'. Thus, the trailing end of tail portion 60 of any given cover member lies below and in trailing relation to (relative to the direction of travel shown in Fig. 1) the leading edge 57 of the main body portion 52 of the contiguous .trailing cover member The under

surface of the trailing end portion of the trail member 60 of a given cover member 50(as viewed in Fig. ll)bears on the neck chain link proper 36. portion 42 of the corresponding underlying

456.552

46.11 172 The underlying and trailing relation of the tail portion of each cover member 50 with respect to the leading edge 57 of the contiguous trailing cover member 50 provides an interfitting relation between each cover member and the contiguous trailing cover member which maintains the cover members 50, 50', etc., in interfitted assembled relation to each other during the entire course of conveyor travel and yet permits relative movement of contiguous cover members 50, 50', etc., with respect to each other within limits to accommodate any necessary movement of the various chain elements which may occur during the course of travel of the conveyor as, for example, in traveling around the end sprockets of the grate conveyor, or during the return run of the conveyor. It will be noted that the trailing end of tail portion of each cover member 50 terminates in a reentrant curve indicated at 62. The/ eecntrnt curve 62 defines a "retainer hook" on tail portion 60.which prevents tail portion 60 of a given cover member from moving out of underlying interfitted engagement with the trailing cover member 50' in the event that the pitch of the chain link assemblies increases,.as might be due to wear on the chain pins or other bearing surfaces. The description in the specification and claims of the tail portion of the cover member 50 as being in "underlying rela- tion" to the contiguous cover member is with reference to the relationship of the members in the upper run of the conveyor. The various dimensions and clearances of the parts are such as to permit each cover member 50 to sit loosely upon its corresponding chain link proper 36 with a limited amount of "play" of the cover member relative to its corresponding chain link proper, while at the same time maintaining the parts in assembled

18, 456.552

46.117

relation with respect to each other as previousl y escrib as

By providing a "loose fit" of the coer mem- shown in the drawings.

her 50 relative to the corresponding chain link proper 36, beat

transfer from the cover member to the chain link proper is reduced.

The grate conveyor chain link construction hereinbefore

described represents an important improvement over the prior art

one-piece chain link construction particularly in the following respects: 1. In the chain link construction of the present imien- heat sield tion, the nonintegral separate cover member serves as a which shields the chain link proper from heat radiatin from the

pellets carried by the conveyor. In addition, the use of the se- from parate cover member significantly reduces thermal conductioi the cover member to the chain link proper, as compared to the prior

art one-piece chain link construction. As a result of these factoEr

for a given operating condition, the chain link proper of the ca-

struction of the invention not only operates at a lower temperature

but also at a more uniform teperature throghout the body thereof

than the chain link proper of the one-piece chain link construction

of the prior art. The construction of the invention thereby sub-

stantially eliminates any thermal stresses in the chain link prope to have and permits the chain link proper of the present invention

greater mechanical strength and stability than the chain link art. proper of the one-piece chain link construction of the prior 2. The use of the construction of the present invention in permits the use of a significant member of slots or apertures the cover member of the chain link, thereby permitting the passage

of hot gases to the material being processed in a heat treatment

19. 456.552

46.117 r

process, with the result that material overlying the chain link is

properly heat treated in the same manner as material overlying a

slotted grate. Inthe prior art one-piece construction in which the chain link cover was substantially unslotted, the pellet load over-

lying the chain link cover was improperly treated and frequently

turned to dust.

3. The use of the construction of the present invention permits the chain pull tensile stress to be carried only by the

chain link proper, with the cover member of the chain link serving

principally as a load support, heat shield and gas passage grid. This is in contrast to the prior art one-piece chain link in which

the integral high temperature cover member was subjected to chain pull tensile stress, which thereby greatly increased chances of

mechanical failure of the chain link.

It will be understood that a complete transverse section of conveyor 10 may include a greater number of grate castings and

a greater number of chain strands than shown in the drawings.

456,552

Claims

46.117 /72 THE CLA~M DEFINING THE INVENTION ARE AS FOLLOWS:

1. A chain link assembly arranged to be pivotally connected by pivot members to adjacent chain link assemblies to form part of a grate conveyor, the chain link assembly comprising a chain link proper as hereinbefore defined, -and

a non-integral and separate cover member serving as a heat shield which covers the entire chain link proper and is pivotally connected at one end thereof to the chain link proper so as -to be in relatively low heat-conduction relation thereto and has limited pivotal movement relative to the chain link proper. A two-piece chain link- assembly according to claim 1 or-

211 wherein the cover member is pivotally connected at said one end thereof to the chain link proper so as to pivot about an axis which is coaxial with the axis of the associated pivot member at -said one end of the chain link proper. 3. Atwo-piece chain link assembly according to claim9, *whereiln the cover member includes a lip portion extending from one end thereof and a tail portion extending from the opposite end thereof, the lip portion being pivotally connected to the chain link proper to pivot about an axis co-axial with that of the pivot member, and the tail portion being received in underlying relation to the cover member

21, 21,456.552

46.117/72 of an adjacent chain link assembly.

A two-piece chain link assembly according to claim/X,

wherein the cover member includes a pair of lip portions

extending from one end thereof, the lip portions being spaced from each other laterally of the cover member, the tail portion of one cover member being received between the lip portions of an adjacent cover member when installed in the chain link assembly. A two-piece chain link assembly according to any one of claims 1 to4, wherein the cover member has gas passages therethrough to define a gas.passage grid. 2. A two-piece chain link assembly as set forth in claim 1, constructed and arranged substantially as herein described with reference to, and as shown in, the accompanying drawings. 7 A A grate conveyor having the two-piece chain link assembly as set forth in any one of claims 1 toA.

DATEDL- this 18 day of JULY 1974. JAMES M. LAWRIE CO..

By: Patent Attorneys for ALLIS-CHALMERS CORPORATION

45.6. 5 5 Z 22.

46.11 772

2~ E

1] '1 1 F-1 Il Illl ll F M-el

46 tv-

Alf 1~~Idle 29 -F I 4

c~4cy4 9 /;AS*

456.55 2 23.

46.117 0(

456,552

4 6.117 fn7

36 Ze

456.552