US3548763A - Grate section for a traveling grate - Google Patents

Description

United States Patent [72] Inventor Hans Farber [56] References Cited k a Germany UNITED STATES PATENTS I2 pp 1,812,125 6/1931 Trainer 110/40 ggf M 3:: 2 232 2,949,289 8/1960 Veith 110/4ox ,038,712 6 1962 N l t l 110 0X 73 Assignee Gutehoflnungshutte-Sterkrade 3 age e a /4 W Pnmary Examiner-Edward G. Favors o sm, Germany Attomey-Mc Glew and Toren [32] Priority Oct. 12, 1967 [33] Germany g 1,583,450 ABSTRACT: A grate section for a traveling grate is formed with a plurality of cross members extending between a pair of side members. Grate bars are supported on the cross members [54] 232 FOR A TRAVELING CRATE and extend forwardly of the cross member on the leading side w g of the grate section and rearwardly of the cross member on the [52] U5. 110/40, trailing side of the grate section for protecting the surfaces of 266/21 these cross members from becoming overheated. Addi- [Sl] Int. F23b 1/22 tionally, the grate bars are movably secured to the cross mem- [50] Field of Search 110/40; bers to prevent their displacement and to accommodate movement in travel and thermal expansion.

PATENTED memo 3.548.763

sum 1 or z FIG] INVEN'I'OR. f/A/VS FARBER PATENTED DEBZZISYU sum 2 0F 2 Arron/vi);

GRATE SECTION FOR A TRAVELING GRATE SUMMARY OF THE INVENTION The present invention is directed to grates .which travel in an endless band having upper and lower runs in the manner of an automatic stoker, and more particularly, it is concerned with individual grate sections making up the traveling grate which are constructed to prevent overheating of the cross members of the grate section. Traveling grates embodying the present invention are useful in sintering or pelletizing fine ores and similar processes.

Grate sections for traveling grates used in the past have transversely extending cross members located at spaced positions along the length of the grate section with the interval between the cross members being determined by the length of the grate bars which rest on the top surfaces of the cross members during the upper run of the graterAs the grate sections travel from the lower run to the upper run, due to the force of gravity the grate bars tend-to slide rearwardly relative to the direction of travel and their displacement inrelationship to the cross members is governed by the amount of play or tolerance provided for during assembly. Accordingly, as a grate section moves upwardly into the upper run its grate bars move rearwardly and cause the leading edge of the leading cross member to be uncovered and exposed directly to the hot charge on the grate and also to the combustion'air. Due to this exposure there is a considerable risk that the cross members will become overheated to an extent which promotes rapid deterioration.

Accordingly, it is a primary object of thepresent invention to provide a grate section construction which prevents exposure of the leading cross member to deleterious effects while providing an efficient traveling grate.

Another object of the invention is to provide grate bars arranged to protect the upper supporting surfaces of the leading and trailing cross members of a grate section.

Still another object of the invention is to provide means on the grate bars for movably securing them to the cross members to afford movement of the grate bars relative to the cross members during the operation of the traveling grate.

Yet another object of the invention is to provide grate bars which are easily assembled on the cross members.

Moreover, another object of the invention is to provide a grate section in which the ends of the grate bars supported by intermediate cross members spaced betweenthe leading and trailing cross members are arranged to accommodate movement of the grate bars during operation of traveling grates.

A further object of the invention is to provide a construction for a grate section which is simple in arrangement, is easy to assembly and affords the maximum protection for the sup port surfaces of the grate section during operation.

Therefore, in accordance with the present invention a grate section for a traveling grate, moving in an endless band and having an upper run and a lower run, is comprised of a plurality of cross members extending transversely to the direction of travel of the grate and being spaced apart at intervals determined by the length of the grate bars supported on the upper surfaces of the cross members during theupper run of the grate. The grate bars are arranged to extend forwardly of or overhang the leading side of the leading cross member of each grate section during the course of its upper run. The overhang of the grate bar protects the upper surface of the leading cross member from the deteriorating effects of the hot charge on the grate and of the combustion air. y

In assembling the grate bars on the cross members they overhang the rear edge of the trailing cross member in the same manner in which they extend forwardly from the leading cross member. It can be appreciated, in accordance with this assembly arrangement, that the grate section can be reversed leading edge for trailing edge because of the symmetrical construction of the section. The grate bars which extend rearwardly from the leading cross member and forwardly from the trailing cross member are supported on an intermediate cross member. However, the oppositely disposed ends of the grate bars supported on the intermediate cross member can be arranged in spaced relationship exposing the upper surface of the intermediate cross member since it is not exposed to the same deteriorating effects as is the leading and trailing of the cross members of the grate section. The spacing of the ends of the grate bars on the intermediate cross member affords the requisite space to accommodate thermal expansion during operation and movement of the grate bars as they travel between the lower and upper runs of the grate. During operation the grate bars cover at least a part of the top surface of the intermediate cross members.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF DRAWINGS In the Drawings:

FIG. 1 is a plan view of a portion of a traveling grate illustrating a grate section in accordance with the present invention; and

FIG. 2 is a cross-sectional view taken along line 11-11 in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 a portion of an endless traveling grate having an upper run and a lower run is shown moving-in the direction of the arrow 9 along its upper run. The'traveling grate is formed of a plurality of grate sections A each having a support section formed of a leading cross member 1, a trailing cross member 2 and an intermediate cross member 3 spaced between the other two cross members. The cross members 1, 2, 3 extend transversely of the direction of travel of the grate and are secured at their opposite ends to side members 4. Mounted on the side members 4 are track members 5 of a conventional type for effecting the travel of each of the individual grate sections. In the direction of travel the leading cross member 1 is set rearwardly from the leading edge of the side members and conversely the trailing cross member 2 is set forwardly of the trailing edges of the side members 4. Y Y

' A plurality of longitudinally extending grate bars 6 are arranged in side-by-side relationship being supported on the upper or support surfaces 1, 2', 3' of the-cross members 1, 2, 3, respectively, during the upper run of the grate, see FIG. 2. As shown in the drawing, on each grate section A the grate bars 6 are divided into two groups 60, 6b. The group 60 of the grate bars are supported at their leading-ends by the leading cross member 1 and at their trailing ends by the intermediate cross member 3, while the grate bars 6 in the group 6b are supported at their leading ends by the intermediate cross member 3 and at their trailing ends by the trailing cross member 2. As displayed in FIG. 2, hook shaped retainers 7, 7 are secured to the lower surface of the grate bars in group 6a as viewed in the upper run and are arranged to engage projecting portions of the upper surfaces 1', 3' of the leading cross member 1 and intermediate cross member 3, respectively. It can be noted that similar retainers 7, 7' are provided on the grate bars which extend from the intermediate cross member 3 to the trailing cross member 2. During the lower run of the traveling grate the grate bars depend downwardly from the cross members and the retainers 7, 7' hold the grate bars in position on the cross members.

The forward ends of each of the grate bars in group 6a and ing the upper run of the grate from possibly deteriorating conditions.

As indicated previously the grate bars are assembled in a symmetrical fashion relative to the intermediate cross member 3 whereby either of the outer cross members of the grate section can be employed to form its leading or trailing side. This affords a distinct advantage over grate section assemblies in which the grate bars cover the top of only one cross member of the grate section and this covered member must be used as the leading edge.

At each of the outer ends 8 of the grate bars 6, that is, along the leading and trailing sides of the grate section, a projection extends perpendicularly to the longitudinal direction of grate bars, and downwardly, as viewed in FIG. 2, along the leading and trailing edge surfaces of the upper surfaces 1', 2'. While the ends 8 of the grate bars 6 protect the upper surface of the support surfaces 1, 2' of the leading and trailing cross members 1 and 2, respectively, the downwardly extending projections 10 also afford protection for the leading and trailing side surfaces of the support surfaces 1, 2'. As can be seen in FZG. l, the side members 4 extend forwardly and rearwardly from the leading and trailing cross members 1 and 2, respectively, and form buffers 12 in the space for accommodating the ends 8 of the grate bars. In assembling the grate bars 6 on the cross members, it will be noted certain tolerances are provided between the opposed surfaces of the grate bars and the cross members. Between the downwardly extending projection 10 on the grate bar and the juxtaposed side surface of the support surfaces ll, 2, there is a clearance S1 provided. On the opposite sides of the cross members 1 and 2 from the projection 10 a clearance S2 is provided between the downwardly extending surface of the retainer 7 and the oppositely facing surface of the upper support surface 1, 2. Similarly at the opposite ends of the grate bars a clearance S3 is provided between the retainer 7 and the adjacent side surface of the upper support surface 3' of the intermediate cross member.

As an individual grate section A moves upwardly from a lower run to an upper run its grate bars 6, due to gravity and the clearances provided in their assembly on the cross members, shift or move rearwardly on the cross members and the projections 10 of the grate bars in group 6a come to rest against the leading side surface on the support surface 1' of the leading cross member 1. The grate bars remain in this position until they reach the end of the upper run of the grate when they are shifted forwardly due to the gravitational force exerted as the individual sections move downwardly to the lower run of the grate. With the projection 10 disposed against the cross member 1 and its end 8 covering the upper surface of the support surface 1, the cross member is protected against exposure both to the heated charge on the grate and to overheating from the combustion air as it travels along the upper run of the grate.

The projection 10 of the grate bar 6 acts as a stop. The distance between the extension 10 and the hooklike retainer 7 which also acts as a rear stop for the grate bar is considerably less than the distancebetween the retainers 7 and 7' at the grate bars. Accordingly, thermal expansion has no significant effect upon the displacement S1+S2 of the grate bars which is governed by the gap i3 provided between the ends of the grate bars on adjacent grate sections. However, as distinguished from the factors affecting the gap 13, the gap 14 located between the adjacent ends of the grate bars in groups 6a and v6!; is closed by the support surface 3' of the intermediate cross member 3 and the gap provides sufficient room for thermal expansion of the grate bars in each of the groups 6a, 617. Accordingly, the clearance S3, between the hooklike extensions 7 and the adjacent support surface of the intermediate cross member 3 must exceed the clearance S1 by an amount at least equal to the extent of the thermal expansion of the bars.

As a result, the thermal expansion is transferred from the gap 13 at the leading edge of the grate section to the gap 14 loeated above the intermediate cross member 3 and in that position there is no adverse affect on the grate during operation, such as in a sintering process.

Because the extension 10 extends outwardly from the outer cross members of each grate section the gap 13 between adjacent grate sections is reduced and this reduction results in improved operations in a sintering process.

At the gap 14 between the ends of the grate bars above the support surface 3' of the intermediatecross member 3 there need be no concern for the exposure provided the cross member because there is no opening afforded for the passage of the combustion air. Similarly, where more than one intermediate cross member is provided in a grate section the opening provided by the gap 14 does not afford any deleterious effect since no through passage for the combustion air is provided.

I claim:

1. A grate section, for a traveling grate arranged to be moved in the longitudinal direction on an endless track for use in sintering and pelletizing and the like, comprises cross members extending transversely of the longitudinal direction of travel of the grate sections, each of said cross members having a support surface thereon, one of said cross members being located along the leading side of the grate section, a plurality of grate bars each having a longitudinally extending main section being supported at one end by said one of said cross members located at the leading side and at the other end by another said cross member spaced rearwardly therefrom, and during at least a portion of the travel of the grate section said grate bars being supported by the support surfaces on said cross members, the ends of said grate bars being supported by said one of said cross members and extending forwardly of said one of said cross members in the direction of travel of said grate for protecting the support surface of said one of said cross members, said grate bars each having a first surface facing outwardly away from said cross members and a second surface facing toward said cross members and being arranged to be supported on said cross members, means secured to said second surfaces of said grate bars for movably securing said grate bars to said cross members, each of said cross members having at least one projection at the support surface thereof extending in the longitudinal direction of the grate section, and said means secured to said grate bar comprising a l'lOOltukE retainer having a first part extending perpendicularly from the second surface of said grate bar toward said cross member and a second part secured to said first part at a position spaced from said grate bar and extending therefrom toward said cross member in generally parallel relationship with said grate bar whereby said hoolclike retainer is arranged to engage said projection from said cross member in overlapping relationship for holding said grate bar on said cross member.

2. A grate section, for a traveling grate arranged to be moved in the longitudinal direction on an endless track for use in sintering and pelletizing and the like, comprises cross members extending transversely of the longitudinal direction of travel of the grate sections, each of said cross members having a support surface thereon, one of said cross members being located along the leading side of the grate section, a plurality of grate bars each having a longitudinally extending main section being supported at one end by said one of said cross members located at the leading side and at the other end by another said cross member spaced rearwardly therefrom, and during at least a portion of the travel of the grate section said grate bars being supported by the support surfaces on said cross members, the ends of said grate bars being supported by said one of said cross members and extending forwardly of said one of said cross members in the direction of travel of said grate for protecting the support surface of said one of said cross members, a pair of longitudinally extending spaced side members, said cross members extending between and being secured to said side members, the leading one of said cross members being located rearwardly of the forward ends of said side members in the direction of travel of the grate section and the trailing said cross member being located forwardly of the trailing ends of said side members in the direction of travel of the grate section.

3. A grate section, for a traveling grate arranged to be moved in the longitudinal direction on an endless track for use in sintering and pelletizing and the like, comprises cross members extending transversely of the longitudinal direction of travel of the grate sections, each of said cross members having a support surface thereon, one of said cross members being located along the leading side of the gratesection, a plurality of grate bars each having a longitudinally extending main section being supported at one end by said one of said cross members located at the leading side and at the other end by another said cross member spaced rearwardly therefrom, and during at least a portion of the travel of the grate section said grate bars being supported by the support surfaces on said cross members, the ends of said grate bars being supported by said one of said cross members and extending forwardly of said one of said cross members in the direction of travel of said grate for protecting the support surface of said one of said cross members, said cross members comprising a leading said cross member a trailing said cross member and at least one intermediate said cross member disposed between the leading said cross member and the trailing said cross member, and said grate bars being arranged in two groups with one of said groups of said grate bars extending from said leading cross member to said intermediate cross member and the second group of said cross bars extending from said intermediate cross member to said trailing cross member.

4. A grate section, as set forth in claim 1, wherein clearance is provided between said hooklike sections on said grate bars and said cross members for permitting relative movement of said grate bar to said cross member while retaining said grate bar secured to said cross members.

5. A grate section, as set forth in claim 3, wherein the ad jacent ends of said grate bars in said one andsecond groups being supported on said intermediate cross member being disposed in spaced relationship for affording thermal expansion of said grate bars.

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