Title of Invention

'A PALLENT CARRIER FOR USE IN SINTERING PLANT"

Abstract

A pallet carrier of the invention has an arrangement wherein side walls (19) are disposed on opposite sides of pallet body (12) and have respective lower portions fixed to respective ends of horizontal walls (22) which extend outwardly widthwise of the pallet body (12) and have horizontal planes (22A) for throttlingly guiding air toward and air-suction opening of the pallet body (12); a horizontal guide space (29) is defined between end portions of grates (11) on the side of the horizontal wall (22) and the horizontal wall in order for horizontally guiding part of the air sucked toward the opening; and the height h1, of the bottom surface of the horizontal guide space (29) in the intermediate portion thereof is equal to the height h2 of that at the opening (9B) thereof. This permits sintered ore dropped through gaps in the grates to substantially vertically bump against the horizontal plane (22A) of the horizontal wall (22), Therefore, the dropped ore is prevented from causing abrasion of the horizontal wall (22), although being accelerated during fall in the horizontal guide space (29).

Full Text

-1A- Field of the Invention The present invention relates generally to a pallet carrier for use in a sintering plant which is having a pallet body provided with side walls at opposite sides of an upper portion thereof, which permits a sinterable material to rest thereon, and an air-suction opening of which is narrower than a space between the opposite side walls for guidingly throttling a flow of sucked air. Description of the Prior Art Fig.2 illustrates a general construction of a sintering plant 1 conventionally used. The conventional sintering plant 1 comprises a plurality of pallet carriers 4 arranged between a raw material feed section 2 and a sintered ore discharge section 3 in an endless fashion and adapted to travel from the raw material feed section 2 to the sintered ore discharge section 3. At the raw material feed section 2 of the sintering plant 1, there are provided a hearth layer hopper 5 for feeding hearth layer ore (not shown) to the pallets 4, a raw material hopper 6 for a drum feeder 6a of a sinterable material to the pallet carriers 4, and an -2-ignition furnace 8 for ignition of a surface of a sinterablc material layer 7. Wind boxes 9 for sucking air from below the pallet carriers 4 are arranged along a travel path from the raw material feed section 2 to the sintered ore discharge section 3. The sintering plant 1 has a construction such that the sinterable material from the drum feeder 6a is deposited on the pallet carrier 4 via the hearth layer ore to be ignited at the ignition furnace 8 and during its travel, the deposited material is subject to a sintering process under air suction effected by the wind boxes 9. The pallet carrier 4 for sintering plant 1, as shown in Figs. 2 to 4, comprises a pallet body 12 to which a frame with guide wheels 10 is mounted by means of mounting bolts and which has grates 11 arranged across an upper surface thereof, and side walls upstanding from opposite sides of the pallet body 12. Each side wall comprises a lower side wall portion 13, and an upper side wall portion 17 which has a lower flange 15 secured to an upper flange 14 of the lower side wall portion 13 by means of a mounting bolt and which is formed with a slope 16 decreasing a deposition width in the light of shrinkage of the material layer 7 caused by sintering. The grate 11 comprises a. plurality of grate bars arranged widthwise of the pallet carrier, said grate bars 3 being supported by a plurality of beams 12A disposed in fore-and-aft relation relative to the pallet body 12. For improvement of the quality of sintered ore, it is important for the wind boxes 9 to suck air in a manner to accomplish uniform sintering of the entire surface of the material layer 7. Unfortunately, however, it is generally difficult to accomplish the uniform sintering of the material layer 7 across the width of the pallet carrier 4. This is because, as shown in Fig.6, the material layer 7 resting on the pallet body 12 of the pallet carrier 4 shrinks to pull away from the upper side wall portions 17 in the sintering process and gaps 5 between the material and the upper side wall portions 17 result. Hence, a quantity of air sucked through the gaps increases while a quantity of air through a midportion of the material layer decreases. Besides, a speed of air flow through material layer portions near the side walls becomes greater than that of air flow through the midportion of the material layer due to a wall effect, resulting in an excessive quantity of air flow through the material layer portions near the side walls. The following measure has been taken to avoid such a disadvantage. Specifically, opposite side walls 19 under the grates are inclined so that an air-suction opening 18 has a smaller outlet width e than an inlet width d, as shown in Fig.7. This arrangement reduces 4 the quantity of air sucked near the lateral sides of the pallet carrier 4. However, the following problem arises in the pallet carrier 4 of the arrangement shown in Fig.7. Some sintered ore (hereinafter referred to as "dropped ore") may drop through gaps (5 mm wide, for example) in the grate during the sintering process of the material layer 7 and slantly bump against the side walls 19 of the opening 18 as accelerated after passage through the gaps in the grate because the opposite side walls 19 of the opening 18 are inclined to define the smaller outlet width e than the inlet width d. This results in abrasion of inside surfaces of the side walls 19. When an already-existing sintering plant is remodeled by inclining the side walls 19 under the grates for defining the smaller outlet width e of the opening than the inlet width d thereof, at least the pallet body 12 must be re-fabricated, thus resulting in increased production costs. Disclosure of the Invention The invention has an arrangement wherein side walls are disposed on opposite sides of a pallet body and have respective lower portions which extend outwardly widthwise of the pallet body and are attached to respective ends of horizontal walls having horizontal planes for guidingly throttling air toward an air- 5 suction opening of the pallet body. The arrangement is further characterized in that a plurality of grates are arranged along a length between the opposite horizontal walls and permit a sinterable material to rest thereon, in that a horizontal guide space is defined between each horizontal walls and end portions of the grates on the horizontal wall side, thereby horizontally guiding part of the air sucked toward the opening, and in that the height of the bottom surface of the horizontal guide space at the opening thereof is the same as the height of that in an intermediate portion thereof. In the above arrangement wherein the bottom surface of the horizontal guide space in the intermediate portion thereof has the same height as that at the opening thereof, the ore dropped through gaps in the grates is accelerated after having passed through the gaps in the grates, but substantially vertically bumps against the horizontal plane of the horizontal wall. Therefore, the horizontal wall suffers less abrasion. Alternatively, the height of the bottom surface of the horizontal guide space at the opening thereof is set to be higher than that in an intermediate portion thereof, so that the flow rate of air slows down toward the opening. Accordingly, all the dropped ore is not sucked into the opening but some of the dropped ore may deposit near the opening. In this case, the deposited dropped ore serves 6 as a buffer, contributing to further reduced abrasion of the horizontal wall. If the deposition of the dropped ore near the opening grows so that the height of the bottom surface of the horizontal guide space at the opening thereof becomes smaller, the flow rate of air therethrough is increased to such extent as to blow the deposited dropped ore toward the opening. Thus, the height of the bottom surface of the horizontal guide space in the intermediate portion thereof becomes substantially the same as that at the opening thereof. This provides a uniform air flow through the sinterable material layer, ensuring that the material layer is uniformly sintered across the entire width thereof. The above arrangement permits many parts of an already-existing pallet carrier to be used, thus accomplishing reduction of the production costs. Additionally, a thermal insulator (also serving as a abrasion-resistant liner) is attached to both horizontal walls along the horizontal guide space. This reduces heat transfer to the horizontal walls, resulting in a reduced thermal stress in the widthwise extensions of the pallet. This facilitates the pallet design. Brief Description of the accompanying Drawings Fig.l is an enlarged view showing a principal portion of a pallet carrier for use a in sintering plant -7-according to an embodiment of the invention; Fig. 2 is a side view showing a general construction of the sintering plant according to the embodiment of the invention and also to a conventional example; Fig. 3 is an enlarged side view showing the pallet carrier; Fig.4 is an enlarged view showing a principal portion of a pallet carrier for use in s sintering plant according to the conventional example; Fig. 5 is an enlarged view showing a principal portion of a pallet carrier for use in a sintering plant according to another embodiment of the invention; Fig. 6 is a sectional view for illustration of the pallet carrier according to the conventional example; Fig. 7 is a sectional view for illustration of the pallet carrier according to the conventional example. Beat Modes for carrying out the invention The invention will be described in detail with reference to the accompanying drawings Fig. 1 and 2. It is note that Fig. 2 and 3 are for the illustration of both an embodiment of the invention and the convention mode. Fig. 2 shows the general construction of the sintering plant 1 according to the embodiment of the invention. The illustrated sintering plant 1 is having -8- a plurality of pallet carrier 4 arranged between a raw material feed section 2 and a sintered ore discharge section 3 in an endless fashion and adapted to travel from the raw material feed section 2 to the sintered ore discharge section 3. As shown in Fig. 1, a pallet: carrier 4 comprises a central body 9A having an air-suction opening 9B, a frame 20 provided with a guide wheel 10, a horizontal wall 22 having a horizontal plane 22A extended widthwise thereof, and a side wall 23 disposed in an upright position as having a lower flange 23a thereof fixed to a flange 22a of each horizontal wall 22 by means of a pair of bolt and nut 24. The pallet carrier 4 further comprises an inclined wall 25 having a lower flange 25a thereof fixed to an upper flange 23b of the side wall by means of a pair of bolt and nut 25 and guidingly throttling air 27 toward the opening 9B. The pallet carrier is provided with a plurality of grates 11 arranged along a length between the opposite side walls for permitting a sinterable material to rest thereon. The grates 11 are supported by a plurality of support beams 21 disposed in a for-and-aft relation relative to the central body 9A. The support beam 21 has an extension 28 extended over the horizontal wall 22. The extension 28 is also provided with a plurality of grates 11A. if is noted that the grates 11 and the grates 11A are of the same configuration. 9 A horizontal guide space 29 is defined between end portions of the grates 11A above each horizontal wall 22 and the horizontal plane 22A in order for horizontally guiding a portion of the sucked air 27 toward the opening 9B. The horizontal guide space 29 is configured such that a height h2 of the bottom surface at the opening 9B thereof is higher than a height h1 of the bottom surface of the horizontal guide space 29 in an intermediate portion thereof. In the above arrangement shown in Fig.2, a hearth layer hopper 5 feeds a hearth layer ore to the pallet carriers 4, and subsequently a raw material hopper 6 feeds the sinterable material to form a sinterable material layer 7. The material layer 7 is ignited on its surface by the ignition furnace 8 and subjected to a sintering process effected by sucking air from the wind box 9 disposed therebelow while the pallet carrier 4 travels with rotation of the guide wheel 10. Thus, the sinterable material is sintered into the sintered ore to be discharged from the sintered ore discharge section 3. When the sinterable material layer 7 is subjected to the sintering process effected by sucking air from the wind boxes 9 beneath the traveling pallet carriers 4, a portion of the sinterable material layer 7 near the inclined wall 25 shrinks to produce a gap 6 between the material layer 7 and the inclined wall 25. 10 In order to prevent that the quantity of air passing through the intermediate portion of the layer is reduced in conjunction with increase in the quantity of air sucked through the gap 6, the embodiment is arranged such that the horizontal walls 22 are provided to define a smaller outlet width e of the opening of the pallet carrier 4 than an inlet width d (plane of grates) of the opening thereof, whereby air sucked along the lateral sides of the pallet carrier 4 is reduced in quantity. This arrangement provides uniform air passage through the sinterable material layer 7 for uniformly sintering the material layer 7 across the width thereof. Since the horizontal guide space 29 is configured such that the height h1 of the bottom surface of the intermediate portion thereof is lower than the height h2 of the bottom surface of the horizontal guide space 29 at the opening 9 thereof, the dropped ore through the gaps in the grates 11A substantially vertically bumps against the horizontal plane 22A of the horizontal wall 22, as being accelerated after having passed through the gaps in the grates (the grates including the gap about 5 mm in width). In contrast to the conventional example, the inventive arrangement is made such that the dropped ore does not slantly bump against the side walls 19 of the opening 18 as being accelerated after having passed through the gaps in the grates, thus the abrasion of the 11 inside surfaces of the side walls 19 can be prevented. Additionally, the horizontal walls 22 suffer less abrasion because the dropped ore substantially vertically bumps against the horizontal planes of the horizontal walls 22, though being accelerated after having passed through the gaps in the grates. An air flow through the horizontal guide space 29 slows down because the horizontal guide space 29 is configured such that the height h2 of the bottom surface at the opening 9B is higher than the height h1 in the intermediate portion thereof. Accordingly, all the dropped ore is not drawn by the wind boxes 9 but some dropped ore may deposit on the horizontal walls 22. In this case, a deposition of the dropped ore serves as a buffer, contributing to further reduced abrasion of the horizontal walls 22. If the deposition of the dropped ore on the horizontal wall 22 grows above the height h2 of the bottom surface of the horizontal guide space 29 at the opening 9B thereof such that a space portion thereat is narrowed, the flow rate of air through this space portion is accelerated to blow the deposition of the dropped ore toward the wind boxes 9. This lowers the deposition on the intermediate bottom portion of the horizontal guide space 29, or the height h1, to substantially the same height as the height h2 at the opening 9B, preventing the horizontal guide space 29 from being blocked. Hence, 12 the air 27 is allowed to uniformly pass through the sinterable material layer 7, ensuring that the material layer is uniformly sintered across the width thereof. The pallet carrier 4 is inverted for discharging the sintered ore while part of the deposition of the dropped ore in the horizontal guide space 29 remains to serve again as the buffer in the subsequent sintering process. In the arrangement shown in Fig.7 wherein the side walls 19 at the opening 18 are inclined to define the smaller outlet width e of the opening 18 than the inlet width d thereof (plane of grates), at least the pallet body 12 must be re-fabricated, resulting in a significant increase in the production costs. According to the embodiment of the invention, the already-existing pallet carrier 4 shown Fig.4, for example, may be re-fabricated (remodeled) by removing the guide wheel 10, lower side wall portion 13 and slope 16 and by remounting the frame 20 laterally of the pallet carrier 4 and adding the extension 28 and grates 11A. This permits the use of many parts of the already-existing pallet carrier so that the production costs can be reduced. The above embodiment is arranged such that the horizontal guide space 29 is defined between the end portions of the grates 11A on the side of the horizontal wall 22 and the horizontal plane 22A in order for 13 horizontally guiding part of the sucked air 27 toward the opening 9B and the height h2 of the bottom surface of the horizontal guide space at the opening 9B thereof is higher than the height h1 of that in the intermediate portion of the horizontal guide space 29. However, it is to be appreciated that the embodiment of the invention should not be limited to this arrangement. For instance, the horizontal guide space 2 9 may be configured such that the height h1 of the bottom surface of the intermediate portion thereof is the same as the height h2 at the opening 9 thereof, and the other portions of the pallet carrier may be constructed the same way as the above embodiment. With this arrangement, as well, the dropped ore which is accelerated while passing through the gaps in the grates, substantially vertically bumps against the horizontal plane 2 2A of the horizontal wall 22. Therefore, the horizontal wall 22 suffers less abrasion. In the above embodiment of the invention, the horizontal guide space 29 is simply configured such that the height h2 of the bottom surface at the opening 9B thereof is higher than or equal to the height h1 of that in the intermediate portion thereof. However, the configuration of the horizontal guide space should not be limited to the above. As shown in Fig.5, a thermal insulator 30 (a liner formed of 25Cr cast iron, for example, and also used for resisting abrasion) may be 14 removably attached to each horizontal wall 22 along the horizontal guide space 29 by means of a pair of bolt and nut 31. The thermal insulator 30 is readily attached to each horizontal wall 22 by using the pair of bolt and nut 31. Such an arrangement improves heat radiation of both horizontal walls 22, benefiting the pallet carrier 4 in terms of thermal stress (less thermal stress is induced in the horizontal walls 22 ) . This facilitates the design of the pallet carrier 4. Although the side wall consists of the upper and lower portions in the embodiment, it may be formed in one piece. As discussed above, the pallet carrier for use in a sintering plant according to the invention is applicable as the pallet carrier for a sintering plant which includes the horizontal guide spaces located at opposite sides of the pallet body and under the grates through which the air is guided while being throttled toward the air-suction opening. -15-WE CLAIM 1. A pallet carrier (4) for use in a sintering plant (1), comprising; side walls (19) disposed on opposite sides of a pallet body (12) and having respective lower portions which extend outwardly widthwise of the pallet body (12) and are attached to respective ends of horizontal walls (22) having horizontal planes (22A) for throttlingly guiding air toward an air-suction opening of the pallet body (12); a plurality of grates (11) being arranged between the opposite horizontal walls (22) in order for permitting a sinterable material to rest thereon; and a horizontal guide space (29) defined between each horizontal walls (22) and end portions of the grates on the horizontal wall side in order for horizontally guiding part of air sucked toward said opening, characterized in that the height of the bottom surface of the horizontal guide space (29) in the intermediate portion thereof is equal to that at the opening thereof 2. A pallet carrier (4) for use in sintering plant (1), comprising: side walls (19) disposed on opposite sides of a pallet body (12) and having respective lower portions which extend outwardly widthwise of the pallet body (12) and are attached to respective ends of horizontal walls (22) having horizontal planes (22A) for throttlingly guiding air toward an air-suction opening of the pallet body (12); a plurality of grates (11) being arranged between the opposite horizontal walls (22) in order for permitting a sinterable material to rest thereon; and a horizontal guise space (29) defined between each horizontal -16- walls (22) and end portions of the grates on the horizontal wall side in order for horizontally guiding part of air sucked toward said opening, characterized in that the height of the bottom surface of the horizontal guide space (29) at the opening thereof is higher than that in the intermediate portion of the horizontal guide space (29). 3. The pallet carrier as claimed in claim 1 or 2, wherein a thermal insulator (30) is attached to both horizontal walls along the horizontal guide space (29). A pallet carrier of the invention has an arrangement wherein side walls (19) are disposed on opposite sides of pallet body (12) and have respective lower portions fixed to respective ends of horizontal walls (22) which extend outwardly widthwise of the pallet body (12) and have horizontal planes (22A) for throttlingly guiding air toward and air-suction opening of the pallet body (12); a horizontal guide space (29) is defined between end portions of grates (11) on the side of the horizontal wall (22) and the horizontal wall in order for horizontally guiding part of the air sucked toward the opening; and the height h1, of the bottom surface of the horizontal guide space (29) in the intermediate portion thereof is equal to the height h2 of that at the opening (9B) thereof. This permits sintered ore dropped through gaps in the grates to substantially vertically bump against the horizontal plane (22A) of the horizontal wall (22), Therefore, the dropped ore is prevented from causing abrasion of the horizontal wall (22), although being accelerated during fall in the horizontal guide space (29).

Documents:

00835-cal-1999-abstract.pdf

00835-cal-1999-claims.pdf

00835-cal-1999-correspondence.pdf

00835-cal-1999-description(complete).pdf

00835-cal-1999-drawings.pdf

00835-cal-1999-form-1.pdf

00835-cal-1999-form-18.pdf

00835-cal-1999-form-2.pdf

00835-cal-1999-form-3.pdf

00835-cal-1999-form-5.pdf

00835-cal-1999-letters patent.pdf

00835-cal-1999-p.a.pdf

00835-cal-1999-priority document others.pdf

00835-cal-1999-priority document.pdf

835-CAL-1999-(07-12-2011)-FORM-27.pdf

835-CAL-1999-(19-12-2012)-FORM-27.pdf