Patent Publication Number: US-6338815-B1

Title: Steel cables driven furnace top chute feeder for blast furnace

Description:
TECHNICAL FIELD 
     The present invention relates to a distributor device provided at the top of a blast furnace, in particular, to a steel cables driven chute feeder which is provided at the top of a blast furnace. This kind of chute feeder can be used for a blast furnace operated under high pressure or normal pressure. It is also suitable for various shaft furnaces which are required for special distribution of bulk material. 
     BACKGROUND TECHNIQUE 
     Currently, there are mainly two kinds of the charging devices for blast furnace, i.e., bell type one and chute type one. The latter is also referred to as bell-less type charging device. Such chute type distributor exhibits following advantages: it has flexible distribution of the bulk material and excellent tightness. Therefore, the chute feeder has been widely popularized in the large-scale blast furnace immediately after it has been proposed. A distributor device is described in for example, such as British Patent Nos. GB 1403687 and GB 1403467, in which planetary differential transmission is provided. However, the construction of said mechanism is quite complex so that it is not easy to produce in cost-effective manner. In addition, its maintenance cost is high. Therefore, Such distributor is not a perfect one which can be used widely. 
     Chinese patent No. 85109284, entitled “Hydraulically driven distributor device” and Chinese patent No. 86104673, entitled “distributor device” both have equivalent performance to the above-mentioned chute feeder with planetary differential transmission. Moreover, these distributor devices are superior to the planetary differential transmission chute feeder in production, installation, maintenance and equipment investment, etc. However, these hydraulically driven devices involve a problem in the respect of liquid-electric power conversion. In addition, the hydraulically driven system is a huge equipment with complex construction so that its investment expenditure is still relatively high. 
     DISCLOSURE OF THE INVENTION 
     Therefore, a primary object of the invention is to provide an economic and practical chute feeder for blast furnace with simplified structure. 
     Another object of the invention is to provide a furnace top chute feeder for blast furnace, in which a steel cable-assembly pulley transmission mechanism is arranged instead of the prior art hydraulically driven mechanism so that the chute feed would have a simplified and more compact structure and is stable and durable while it can be produced with lower cost. Moreover, its control accuracy is so high that various requirements for the distribution process for blast furnace can be sufficiently satisfied. Therefore, the chute feeder according to the invention is appreciated to be popularized. 
     According to the invention, there is provided a furnace top chute feeder for blast furnace, mainly comprising: a transmission-case cover; a transmission-case body carrying said transmission-case cover; a water cooled base provided beneath said transmission-case body for receiving the water used to cool a rotary sleeve and a choke; directional limit means for vertical translation provided for reciprocating a vertically translational large bearing while keeping it in the horizontal state; and chute distributing means for feeding the charge material into the furnace chamber of blast furnace, comprising a chute for carrying the charge into the furnace chamber, a chute carriage for supporting the chute, and a chute rotary system for rotating the chute in the furnace at a certain angle, the characterized in that, it further comprising chute oscillatory system for changing continuously or step by step the angle a between the chute and the axis of the rotary sleeve in a certain range by means of steel cable-assembly pulley transmission, said chute oscillatory system can either make the chute oscillate independently or make the chute oscillate in combination with the rotation of the chute. 
     According to an aspect of the invention, said chute oscillatory system comprises: a steel cable winding drum on which a drag steel cable is wound; chute oscillatory reduction gear for transferring the power resulting in the chute oscillatory motion to said steel cable winding drum; a plurality of upper fixed pulley provided on the transmission-case cover; a vertically translational large bearing, the inner ring of which can be rotated and its outer ring can only be translated upwardly and downwardly; a plurality of movable pulley spaced uniformly along the periphery of the backing ring of the vertically translational large bearing, these movable pulley being pulled by the drag steel cable coming from said steel cable winding drum so that the vertically translational large bearing can be translated up and down; a backing ring of the vertically translational large bearings; a crank tailing wheel frame; a connection shaft for mounting said crank tailing wheel frame on the inner ring of said vertically translational large bearing, crank tailing wheels provided at the rear portions of the cranks respectively and located in the guide groove formed in the crank tailing wheel frame; a movable pulley pulled by said drag steel cable; and a steel cable which is passed through said upper fixed pulleys and passed around a plurality of movable pulleys arranged on the backing ring of the vertically translational large bearing, respectively so as to form a closed ring. 
     Moreover, the number of said movable pulleys is n, where n is 2-4; the number of the pairs of the upper fixed pulleys mounted on the transmission-case cover is 2n, where n is 2-4; and the number of the movable pulleys fixed on the transmission-case cover is 2n, wherein n is 2-4. The movable pulleys n are arranged in two fashion: coaxial arrangement and in-line planar arrangement. 
     According to one preferred embodiment of the present invention, a fixed pulley for changing the movement direction of the drag steel cable one time is provided on the bottom portion of said transmission-case body. 
     According to another preferred embodiment of the invention, an assembly pulley for pulling said drag steel cable is provided. The assembly pulley includes two parallel lower fixed pulley and a movable pulley fixed on the pedestal of said movable pulleys. 
     In addition, said directional limit means for vertical translation includes a plurality of vertical guide posts arranged uniformly along the periphery of the transmission-case body of the chute feeder, a plurality of directional limit rollers for vertical translation arranged between the backing ring of the vertically translational large bearings and vertical guide posts, the number of which corresponds to vertical guide posts, adjustable supports of directional limit rollers of vertical translation provided on a plurality of corresponding strengthening ribs of the backing ring of the vertically translational large bearings, support shafts, and adjusting screws for adjusting the extent of compressing of the rollers, wherein the number of the vertical guide posts is in the range of 6 to 12, the directional limit rollers for vertical translation are provided with 6 to 12 in pairs correspondingly, and the strengthening ribs are provided for 6 to 12. 
     Moreover, a motor for diving the chute to oscillate is a AC permanent-magnet servo motor controlled by a AC servo actuator. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention may be better understood and its numerous objects and advantages will become apparent to those skilled on the art by reference to the accompanying drawing in which: 
     FIG. 1 is a schematic view of a steel cables driven furnace top chute feeder for blast furnace according to one embodiment of the invention; 
     FIG. 2 is an elevation view of vertically translating mechanism driven by steel cables; 
     FIG. 3 is a side view of vertically translating mechanism driven by steel cables; and 
     FIG. 4 is a bottom plan view of vertically translating mechanism driven by steel cables. 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     As shown in the drawings, the invention provides a chute feeder provided at the top of blast furnace and driven by steel cables. 
     It is well known that the furnace top chute feeder for blast furnace is provided on the top cone of a blast furnace and is connected with a charge tank at its top end. The use of such a chute feeder is to supply scientifically the charge material stored in the charge tank into furnace in accordance with the requirements of the smelting process of blast furnace. 
     The chute feeder driven by a steel cable is a cylindrical box-like apparatus, and the center line of the chute feeder coincides with that of the blast furnace. The charge is passed through the choke arranged at the center area of the chute feeder along the center line of the furnace and fallen on the chute. After that, the charge slides to the charge surface of the furnace throat through the rotating chute. In order to satisfy the requirements of the smelting process of blast furnace, it is required that the chute can either be rotary or oscillatory. 
     As shown in the drawings, a transmission case is mounted on the top cone of the blast furnace. A large flange of its body  8  is butt joined to a top ring  17 . A water cooled base  16  is provided between the transmission-case body  8  and the top ring  17 , the function of which is to receive the water used to cool a rotary sleeve  30  and a choke  31  and discharge the cooled water out off the transmission-case body through a discharge pipe provided thereon so that the heat transferred from the inside of the furnace via heat-absorbing surfaces is brought away and various mechanical parts in the transmission case are thus kept to operate normally and are prevented from possible damage caused by high temperature. 
     According to the invention, the furnace top chute feeder mainly comprises a transmission-case cover  1  mounted on the transmission-case body  8 , the water cooled base  16 , the rotary sleeve of the chute  30 , the choke  31 , a wear-resistant bushing of the choke  32 , directional limit means for vertical translation and two drive systems which can be operated either independently or in combination. 
     The chute rotary system comprises: a motor  29  for driving the chute to rotate, a reduction gear  28 , a driver pinion  26 , an upper hanging bearing  27  with its inner ring fixed on the transmission-case cover  1 , the chute rotary sleeve  30  fixed on the outer ring of the upper hanging bearing  27 , lugs  21 , a chute carriage  19  hanged in the lower portion of the rotary sleeve  30  by means of lugs  21 , and a chute  20  engaged in the chute carriage  19 . 
     Two symmetrically arranged lugs  21  are projected out the rotary sleeve  30  and extended into the transmission case. Two cranks  22  are provided respectively and symmetrically at each end portion of the projected lugs. Said two cranks have the same length and extend parallelly to each other. The angle of the cranks is determined by the angle of the chute after assembly. 
     Also, the chute oscillatory system further comprises: a chute oscillatory actuator motor  4 , a chute oscillatory reduction gear  3 , a steel cable winding drum  2  provided on the transmission-case cover, drag steel cable  7 , closed-ring steel cable  15 , lower fixed pulley  10 , four movable pulleys  6  provided at the periphery of a backing ring of a vertically translational large bearing, eight upper fixed pulleys arranged at the inside of the transmission-case cover  1  and corresponding to the four movable pulleys  6 , two movable pulleys  9  for dragging the steel cable coming from the fixed pulleys  5 , the backing ring of the vertically translational large bearing  14 , a vertically translational large bearing  25 , the inner ring of which can be rotate and its outer ring can only be translated up and down, a crank tailing wheel frame  23 , connection shafts  24  for connecting said crank tailing wheel frame to the inner ring of said vertically translational large bearing, and crank tailing wheels  36  provided at the rear portions of the respective cranks respectively and located in the guide grooves formed in the crank tailing wheel frame  23 . 
     Since the crank tailing wheel frame  23  is secured on the inner ring of the vertically translational large bearing by means of the pivots  24  along the center line of the rotary sleeve  30  and vertically to the connection line of the centers of the tailing wheels, the direction of the extension of the pivots  24  are vertical to the axial direction of the tailing wheels and crosses the latter in a plane. Such a structure has the function of a universal joint. Therefore, this structure can eliminate strong destructive power due to inconsistent in the length of cranks, the cranks not being parallel to each other, lugs not extending in the horizontal direction, rotary sleeves not being vertical or coaxial, and the like. The inner ring of the vertically translational large bearing can be rotated by the roller provided on one of the two pivots for connecting the crank tailing frame to the inner ring of the vertically translational large bearing being turned via a poke groove formed on the rotary sleeve. The rotary movement of the inner ring of the vertically translational large bearing is a passive rotary movement. As long as the rotary sleeve is rotated together with the chute, the inner ring of the vertically translational large bearing is rotated. 
     The major portion of the above-mentioned chute oscillatory system is arranged in the transmission case, except that the steel cable winding drum  2 , reduction gear  3  and the actuator motor  4  are mounted at the outside of said transmission case. The reduction gear  3  and the actuator motor  4  are arranged in a special motor house away from the transmission case of the chute feeder so that the operation environment of the motor can be improved and the lift time of the motor can be thus extended. 
     In order to make the vertically translational large bearing to translate vertically, directional limit means for vertical translation is provided, which includes the backing ring of the vertically translational large bearings  14 , the strengthening ribs of the backing ring of the vertically translational large bearings  35 , adjustable supports  13  of the directional limit rollers of vertical translation, support shafts  33  of the adjustable supports of directional limit rollers of vertical translation, adjusting screws  34  for adjusting the extent of compression of the directional limit rollers of vertical translation, eight vertical guide posts  11  spaced apart uniformly along the cylindrical wall of the transmission-case body, and a plurality of directional limit rollers for vertical translation. 
     Next, the operation mechanism of the chute rotary system will be described. In operation, the pinion  26  is rotated by the actuator motor  29  through the reduction gear  28 , and the pinion  26  brings the large gear integrated with the outer ring of the upper hanging bearing  27  into rotation so that the chute rotary sleeve  30  coaxial with the large gear, i.e., with the outer ring of the upper hanging bearing  27  and fixed together and the lugs  21  which are secured on the sleeve, together with the chute carriage  19  hanging at the lugs  21  and the chute  20  engaging at the chute carriage  19 , are rotated around the center line of the blast furnace, thus the rotation of the chute is achieved. 
     The power generated by the chute oscillatory actuator motor  4  is transferred through the reduction gear  3  and the steel cable winding drum  2  so that the steel cable  7  is dragged. Then the steel cable  7  drags the movable pulleys  6  of the backing ring of the vertically translational large bearing via the lower fixed pulley  10 , movable pulleys  9  and upper fixed pulleys  5 . The vertically translational large bearing  25  is thus moved up and down so that the crank tailing wheel frame  23  is brought to move up and down. Therefore, the crank  22  is pulled via the crank tailing wheels  36  so as to make it rotate around the lugs  21  while the chute carriage  19  is rotating around the lugs  21 . The angle of rotation is in the range of 0°-60°. The vertical position of the chute  20  is set to be 0°. Therefore, the chute  20  is oscillated in a angle of α. The upward swing of the chute  20  is obtained by the dragging of the steel cable  7  and its downward swing is achieved by its own gravity. Under the natural suspended balance point of the chute  20 , the chute is forced to fall down by means of the weights of the vertically translational large bearing  25 , the backing ring of the vertically translational large bearing  14 , the crank tailing wheel frame  23  and the like until to be 0°, that is, the chute is in its vertical position. 
     The chute  20  can be rotated. Meanwhile, the chute  20  can be swung by the up-and-down linear movement of the vertical translational large bearing  25  being changed to the swing of the chute carriage  19  and the cranks around the lugs. The rotation of the chute  20  is a separate movement independent of the oscillatory movement of the chute  20 . However, these movements can be carried out separately or in combination. The cross point of the two movements is in the balls of the vertically translational large bearing  25 . 
     In order to make the vertically translational large bearing  25  to be moved up and down smoothly and stably, in addition to the limit means consisted of eight vertical guide posts  11  and eight pairs of adjustable directional limit rollers for vertical translation  12 , it is quite necessary to make the circumferential tension of the backing ring of the vertical translational large bearing  14  uniform. For this purpose, the following measures are taken: 1. four movable pulleys  6  are secured uniformly on the periphery of the backing ring of the vertical translational large bearing  14 ; 2. four pairs of the upper fixed pulleys  5  are arranged on the transmission-case cover  1  correspondingly; a steel cable is passed through the four pairs of the upper fixed pulleys  5  and passed around four movable pulleys  6  of the backing ring of the vertical translational large bearing  25 , respectively so that a closed-ring steel cable  15  is formed. When the close-ring steel cable is passed through four pairs of upper fixed pulleys, four sides will be formed. Two opposite sides are pulled toward two pairs of fixed pulleys which are collectively arranged on the transmission-case cover  1  and then pulled toward movable pulleys  9 . The movable pulleys  9  are connected to and pulled by the steel cable  7  which is unwound from the steel cable winding drum  2  so that the movable pulleys  9  will drag the close-ring steel cable  15 . Thus, the close-ring steel cable  15  drags the movable pulleys  6  of the backing ring of the vertical translational large bearing  14  so that each of the four movable pulleys  6  are subject to the action of the close-ring steel cable  15  and operated synchronously. The two dragging manner of the steel cable  7  are described as below. One is that a fixed pulley  10  is arranged at the lower portion of the transmission-case body  8  so that the steel cable  7  will change its direction of extension only one time and wind the steel cable winding drum  2  directly. The other dragging manner is that such a assembly pulley is arranged that the lower fixed pulley  10  is composed of two fixed pulleys and a further movable pulley is arranged at the movable pulleys  9 . The steel cable  7  will change its direction of extension many times when it passes such assembly pulley so that the drag force will be reduced to one fourth of the former manner, the winding length of the steel cable  7  will be increased three times and the winding turns of the steel cable winding drum  2  will be also increased three times, thus the power of the chute oscillatory actuator motor  4  can be reduced and the positioning accuracy of the chute can be improved. 
     The steel cable winding drum  2  is driven by a AC permanent-magnet numerical control servo motor. Since such kind of motor has good speed regulation performance, the control accuracy of the chute oscillation made by the steel cable transmission mechanism is superior to the oscillatory positioning accuracy of the prior art. 
     While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation. 
     Exploitation in Industry 
     The present invention has the following advantages: 
     1. The use of the steel cable-assembly pulley transmission can ensure the vertical translational bearing to move stably and smoothly without jamming and creeping so that the problem of the prior art, i.e., the three hydraulic cylinders need to be synchronized, can be solved completely; 
     2. Compared to the planetary differential transmission or the hydraulic transmission, the structure of the chute feeder according to the invention can be manufactured at lower cost since its structure is simpler and it is easy to be maintained. Moreover, the chute feeder of the invention has higher reliability. 
     3. The AC servo actuator used for precision numerical control machine is used to drive the chute oscillatory system. As compared with the hydraulic transmission or normal motor drive, positioning accuracy is high due to in the absence of electric-hydraulic conversion. There still have further advantages in the present chute feeder, such as the motor has large and constant output torque with small volume and is free of maintenance; the response time is extremely short; the speed regulating range is wide; the chute oscillatory system of the invention can be subject to repeated over load; the performance of operation at lower speed is good; the noise is low; it is suitable for operation in the severe conditions, such as work in dusty environment, high temperature or humid environment; integrated cellular structure is easy to be mounted, maintained and replaced, has high reliability and consistency, and has perfect protection performance. 
     4. Since the hydraulic station of the prior art oscillatory system is deleted, the equipment weight of the present chute feeder is reduced so that the amount of investment is decreased. 
     To sum up, the furnace top chute feeder according to the invention is durable and stable with simpler and more compact structure and economic cost. In addition, its control accuracy is so high that the requirements for distribution process for blast furnace can be sufficiently satisfied. Therefore, the chute feeder according to the invention is appreciated to be popularized.