US2041472A - Method of and means for sintering and roasting ores and the like - Google Patents

Description

May 19, 1936. A. HOLMBERG w 9 METHOD OF AND MEANS FOR SINTERING AND ROASTING ORES AND THE LIKE Filed Feb. 7, 1935 2 Sheets-Sheet l Fiif ifi iiiliti iiil METHOD OF AND MEANS FOR SINTERING AND ROASTING ORES AND THE LIKTEI G E B M L O H A Filed Feb. '7, 1955 2 Sheets-Sheet 2 a v w J b v Patented May 19, 1936 UNITED STATES METHOD OF AND MEANS FOR SINTERING AND ROASTING ORES AND THE LIKE Anders Holmberg, Stockholm, Sweden, assignor to Helge Gustaf Torulf, Stockholm, Sweden Application February 7, 1935, Serial No. 5,456 In Sweden August 3, 1933 3 Claims.

The continuous apparatus for sintering or roasting of ores, purple ores, slimes and the like hitherto in practical use which have an endless channel in which the goods are charged together with solid pulverulent fuel and. sintered or roasted, involve high erecting costs for the machinery as well as for the high buildings required. Furthermore, it is often difiicult to obtain in such apparatus a uniform and fully satisfactory production of sinters; also the quantity of so-called return goods which must be resintered will often be rather high. For avoiding said drawbacks it has been proposed to substitute for the endless channel a plurality of separate sintering pans arranged as carriages which during the sintering operation are connected to a continuous string which is fed continuously or intermittently on a track above an oblong suction chamber but otherwise are transportable independent of each other for facilitating the emptying of the finished sinter and the returning of the pans to the front end of the sintering track. Such constructions, however, have given no practical results, inter alia on account of the difiiculties, which have been connected with the supply of the suction air required for the sintering through the movable sintering pans to the stationary suction devices and the controlling of the suction action in the individual pans as required in the progress of the sintering operation.

This invention relates principally to a method of sintering, roasting and the like in a plant of the last mentioned type having sintering pans carried out as independent units whereby it is possible to bring about with comparatively simple means an effective suction action at the individual pans in use and to control as desired said suction action at each separate pan or group of pans. According to the invention the sintering pans carried out as independent units are fed in the form of a string above a series of suction boxes or the like and simultaneously and synchronously with the pans a movable element in the form of a band or the like is fed between the pans and the suction boxes, said band transferring a controllable suction action through openings in it from the diiferent suction boxes to the pans over them.

The invention is illustrated more in detail in the accompanying drawings which show a sintering plant in accordance therewith. Fig. 1 shows a diagrammatic side elevation of a portion of the plant, Fig. l an extension of Fig. 1, Fig. 2 a diagrammatic plan view of a portion of the plant, Fig. 2 an extension of Fig. 2, and Fig. 3 a crosssection thereof on the line III--I1I of Fig. 2.

Fig. 4 shows a cross-section of the sintering means proper on a larger scale.

The plant comprises a plurality of preferably circular sintering pans I to 9 arranged as independent units and provided with wheels for facili- 5 tating their transport. During the sintering operation the pans are placed in a row on a track ID, on which they are fed continuously or intermittently. The feeding is efiected by means of two endless drawing chains II which run over chain wheels I2, l3 of which the wheels I3 are provided with suitable driving means while the wheels l2 may be idle. The drawing chains II are provided with pins M for driving the pans placed on the track It, said pins engaging downwardly extending projections l5 on the pans. The distance between the pins 14 on the drawing chains is suited to the size of the pans so that the different pans during the feeding run close to each other without pressing against each other. Between and below the rails of the track ID a series of suction chambers or suction boxes IE to 23 is provided, said boxes being connected separately by means of pipings 24 with independent suction fans for effecting an independently controllable 20 suction action through each suction box. Said suction fans are shown at 25 in Figs. 2 and 3. The suction boxes l6-23 are provided at the top with longitudinal openings on their whole length. Said openings are covered by the upper part of the endless steel band 21 which runs over rolls or pulleys 28, 29 preferably mounted on the same shafts as the chain wheels l2, l3 and having the same diameter as the pitch circle of the latter so that the band is fed synchronously with the same speed as the drawing chains. When the plant is in use and vacuum prevails in the suction boxes the upper part of the band 21 is pressed by the atmospheric pressure against the upper plane walls of the suction boxes on both sides of the longitudinal openings so that tightness of the suction boxes is obtained. To reduce friction and improve tightness on the feeding of the band additional longitudinal packing strips 45 (Fig. 4) may be fixed in the upper walls of the suction boxes. Yielding transverse packing strips 46 (Fig. 1) engaging the lower side of the band 21 provide for tightness between adjacent suction boxes. The band 21 is provided with openings 30 (Fig. 4) situated at distances from each other 50 corresponding to the distances between the centres of the pans fed on the track Hi, the band 21 being so adjusted in relation to the pans that such an opening is located below a socket 3| extending downwards from each pan, the lower end of such socket providing substantial tightness against the band around the opening 30.

In front of the inlet end of the track 10 is a storing pocket 32 provided with a charging device 33 by means of which each individual pan is charged with a mixture of the goods to be sintered and solid pulverulent fuel after it has been placed on a rotatable platform or turntable 34. At the delivery end of the track a discharging device for the sintered goods is provided, said device consisting for instance of a turnable tipping frame 35 on which the finished pan is placed and by means of which it is tilted after looking, the sinter goods being stored in a pocket 36 from which they are delivered to an automatic transporting receptacle 31. The latter delivers the goods to a sieving device 38 of any well-known construction which separates the sinter, the bed material and the return goods from each other and delivers the sinter for instance into railway wagons 39 while the bed material and the return goods are returned by means of devices not shown in the drawings to the charging place or to a store for raw materials. The bed material is used in usual manner to protect the grates of the pans and is charged in the emptied pans before the material to be sintered is charged. The return goods are mixed with the other raw material and are resintered. A fan 40 may be provided at the tipping place for removing dust and smoke arising in tipping.

Immediately after tipping the emptied pans are delivered to an automatic elevator 4! by means of which they are moved to a track 42 provided below the track ID, the track 42 being, preferably, inclined to such extent that the pans due to gravity roll back to the charging end where they are taken up by an elevator 43 by means of which they are transported to the level of the track I0 and then moved into position below the charging device 33. As soon as a pan has been charged it is moved by hand onto the inlet end of the track ID where the pan is caught by a pair of pins M on the drawing chains H and is brought thereby into such position in relation to the synchronously moved band 27 that its socket remains above an opening in the band 21. Immediately after the charged pan has been placed on the track and has been exposed to the suction action of the first suction box IE it is ignited by means of an igniting apparatus 44 temporarily placed above the pan. The pan is then entrained in an unaltered position in relation to the band by a pair of pins [4 on the drawing chains H and is moved forward along the track, the upper part of the band moving forward with the same speed so that the connection between the pan and the subjacent suction boxes is maintained through the opening in the band. On account of the fact that the suction boxes are separated from each other the vacuum in each individual suction box may be adjusted as desired and thus a controlled supply of air to each separate pan be obtained in any position on the track, each pan working substantially independently of the others. In this manner it is ensured that sintering progresses in each separate pan with the desired speed so that it is finished when the pan reaches the delivery end of the track. Furthermore, the advantage is attained that the consumption of power for the vacuum suction is reduced to a minimum as the vacuum need not be maintained higher in any suction box than is required for drawing through the required combustion air at the stage of sintering which the pan above the suction box has attained.

The invention is not limited to the constructional embodiment of the plant shown in the drawings. To facilitate the feeding of the pans on the track the latter may be somewhat inclined in the feeding direction. The band 21 is, preferably, arranged in the form of a thin flexible steel-band. To prevent its bending due to the atmospheric pressure at the portions which are above the longitudinal openings in the upper side of the suction boxes said openings may if desired be divided by cross-stays which support the band.

What I claim is:

1. The method of sintering and roasting ores, purple ores, slimes and the like, which comprises charging the material to be treated and pulverulent solid fuel in independent movable sintering pans, feeding said pans after ignition of the charge successively together with a perforated endless band over a series of independent suction boxes, and subjecting the pans during the sintering operation to a controllable and variable suction action from the individual suction boxes by the intermediation of the perforated endless band.

2. A plant for carrying out the method set forth in claim 1, which comprises a plurality of independent sintering pans, a sintering track, a series of stationary suction boxes below the track, independently operating suction means connected individually to groups of the suction boxes, an endless band having opening to provide for the transfer of the suction action from the individual suction boxes to the pans, and means for synchronously feeding the pans on the track and the band assisting the suction action.

3. A plant for carrying out the method set forth in claim 1, which comprises a sintering track, a series of stationary suction boxes below said track, means for creating a variable and different vacuum in successive groups of the suction boxes, an endless perforated band to provide for the transfer of the suction action from the individual suction boxes to the pans, means for synchronously feeding the pans on the sintering track and the band assisting the suction ac tion, a charging device at one end of the sintering track, a discharging device at the other end of the sintering track, and a return track below the suction boxes for the transport of the emptied pans from the discharging device to the charging device.

ANDERS HOLMBERG.

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