PAPER-MAKING MATERIAL DEPOSITION APPARATUS

Abstract: A paper-making material deposition apparatus includes a tower (1) having a paper-making material inlet (2) provided at the center of the top thereof for depositing a paper-making material in the inside thereof, a stirrer (3) rotatable in a substantially horizontal plane in and adjacent to the bottom (1′) of the tower and having diluting-water jet nozzles (6) and diluting-water supply passages (13) leading to the jet nozzles, and a driver (12) disposed beneath the tower bottom for rotating a shaft (7) depending integrally from the stirrer and penetrating the center of the tower bottom.

Description: This invention relates to a paper-making material deposition apparatus of the tower type, in which a paper-making material with a concentration of 10 to 30% is charged into a tower from an inlet at the top to be deposited and diluted and progressively taken out of the tower from the bottom thereof. The prior art paper-making material deposition apparatus of the type referred to above is used as a virgin pulp stock tower or an ink removal tower for causing swelling of paper-making material consisting of used paper in the presence of an ink-removing agent while liberating or making easier the liberation of ink adhering to the material. The apparatus comprises a tower having a paper-making material inlet provided at the top for depositing the paper-making material in the inside and a stirrer rotatable in a horizontal plane in and adjacent to the bottom of the tower and having diluting-water jet nozzles and diluting-water supply passages leading to the jet nozzles (as disclosed in, for instance, Japanese Patent Publications SHO 55-37638 and SHO 57-55835). In this prior art apparatus, a driver including a motor and a speed reduction unit is disposed on the tower top for rotating the stirrer, and the driver transmits drive force to the upper end of a vertical shaft, to the lower end of which the center of the stirrer is secured, and which is supported at the center of the tower bottom and the center of the tower top. The stirrer is rotated in a deposited paper-making material layer on the tower bottom while jetting diluting water from the jet nozzles. Some such towers are of a gigantic size having a diameter of 10 m and a height of 20 m. The top of the vertical shaft is journaled at the center of the tower top, and the driver is disposed near the center. Therefore, the paper-making material inlet has to be provided at an eccentric position with respect to the tower top center. Therefore, the top surface of the paper-making material deposited in the tower is not uniform in level but is higher in level in the neighborhood of a position directly underneath the paper-making material inlet. For this reason, the load exerted on or resistance offered to the stirring wings of the stirrer rotated horizontally adjacent to the tower bottom by the vertical shaft which is as long as 20 m varies greatly. This means that the vertical shaft support unit and stirrer have to have considerably high mechanical strength. An object of the invention is to provide a paper-making material deposition apparatus in which a substantially uniform load is applied to the stirring wings of the stirrer. To attain the above object of the invention, there is provided a paper-making material deposition apparatus comprising a tower having a paper-making material inlet provided at the top for depositing a paper-making material in the inside and a stirrer having stirring wings rotatable in a substantially horizontal plane in and adjacent to the bottom of said tower and having diluting-water jet nozzles and diluting-water supply passages leading to said jet nozzles, said stirrer having an integral shaft depending from the center thereof and penetrating the center of the tower bottom, a driver for rotating said shaft being disposed beneath said tower bottom. The driver disposed beneath the tower bottom center transmits drive force to the shaft integrally and downwardly extending from the stirrer and penetrating the tower bottom center. Thus, the convential vertical stirrer support shaft can be dispensed with, and the paper-making material inlet can be provided near the tower top center. Thus, the paper-making material charged into the tower can be uniformly distributed from the center, and there is no need of particularly reinforcing the mechanical strength of the stirring wings of the stirrer. The above and other objects and features of the invention will become more apparent from the following detailed description with reference to the accompanying drawings. Figure 1 is a side sectional view showing an embodiment of the paper-making material deposition apparatus according to the invention; Figure 2 is a sectional view taken along line II-II in Figure 1; Figure 3 is a fragmentary enlarged-scale sectional view showing the apparatus of Figure 1; and Figure 4 is a view similar to Figure 1 but showing a different embodiment of the paper-making material deposition apparatus according to the invention. Figures 1 to 3 show a first embodiment of the paper-making material deposition apparatus according to the invention. Referring to the Figures, reference numeral 1 designates a tower, 2 a paper-making material inlet provided at the center of the tower top, and 3 a stirrer rotatable in a horizontal plane in the tower adjacent to the bottom thereof. The stirrer 3 includes a hollow central stem 4 and a plurality, i.e., two in this embodiment, of hollow horizontal stirring wings 5 circumferentially uniformly spaced apart around and extending outwardly from the stem 4. Each stirring wing 5 has a plurality of diluting-water jet nozzles 6 provided at a predetermined interval along its front surface in the direction of its rotation as shown by the solid arrow in Figure 2. A hollow short shaft 7 depends integrally and concentrically from the lower surface of the stem 4. Below the center of the bottom 1' of the tower 1, a space 8' is formed in a concrete foundation 8. A frame 9 is built on the bottom of the space 8' such that it surrounds a lower half of the shaft 7. An inner race 10a of a bearing 10 is secured to the top of the frame 9 such that it is concentric with the shaft 7. The shaft 7 is provided with a flange 11 extending from its outer periphery. An outer race 10b of the bearing 10 is secured to the lower surface of the flange 11. The outer periphery of the outer race 10b is provided with a gear 10c, which is in mesh with a gear 12' provided on an output shaft of a driver 12 disposed on the frame 9 and consisting of a motor, a speed reduction gear train, etc. The bearing 10 serves to receive the drive force from the driver 12 and enables smooth rotation of the flange 11, and hence the stirrer 3 integral with the shaft 7. In addition, it receives the thrust of the stirrer 3. In this first embodiment, the inside of each stirring wing 5 of the stirrer 3 has a dual structure. An inside pipe 5' of the stirring wing 5 serves as a paper-making material take-out passage 14 which has a paper-making material suction port 14' open at the end of the stirring wing 5. A space defind between the inner surface of the stirring wing 5 and the outer surface of the inside pipe 5' serves as a diluting-water supply passage 13. Instead of this dual structure, the inside of each stirring wing 5 may be divided by a partition member (not shown) into a diluting-water supply passage 13 extending along the front surface and a paper-making material take-out passage 14 extending along the rear surface. A cylinder 15 spaced apart a distance from and surrounding an upper half of the shaft 7 depends from the lower surface of the central stem 4 of the stirrer 3, and its lower end sealedly and rotatably downwardly extends into an upper joint box 16 rotatably and sealedly mounted on the outer periphery of the shaft 7. A diluting-water supply ductline 17 is connected to the upper joint box 16, and the upper end of a cylindrical space defined inside the cylinder 15 is communicated through a communication hole 4' formed in a lower portion of the wall of the stem 4 with the diluting-water supply passage 13 in each stirring wing 5. When the stirrer 3 is rotated in unison with the shaft 7 and cylinder 15 at a rate of 15 to 20 rpm from the driver 12 while supplying diluting water to the upper joint box 16, the diluting water is caused to rise through the cylindrical space surrounded by the cylinder 15 to enter the inner space of the stem 4 through each communication hole 4' and flow to each passage 13 so as to be jetted from the jet nozzles 6. In order to be able to extract the diluted paper-making material at the tower bottom to the outside of the tower 1 during the rotation of the stirrer 3, the upper end of the shaft 7 and paper-making material take-out passage 14 in each stirring wing 5 are communicated with each other by a joint cylinder 18. The lower end of the shaft 7 sealedly and rotatably downwardly extends into a lower joint box 19 secured to the bottom of the space 8' in the concrete foundation 8, and a paper-making material extraction ductline 20 communicated with a suction pump (not shown) is connected to the tower joint box 19. With the first embodiment having the above construction, as in the prior art structure disclosed in the Japanese Patent Publication SHO 57-55835 mentioned earlier, it is possible to cause rotation of the stirrer 3 in a horizontal plane adjacent to the tower bottom to cause diluting water to be jetted from the jet nozzles 6 on the front surface of the stirring wings in the direction of rotation so as to dilute the paper-making material on the tower bottom to a concentration of about 4% if the concentration before the dilution is about 10% and enable the diluted paper-making material to be extracted through the paper-making material suction port 14', paper-making material take-out passages 14 in the stirring wings 5 and shaft 7. In this embodiment, the paper-making material take-out passage 14 is provided in each of the two stirring wings 5, but it is possible to provide a take-out passage in only a single stirring wing. Figure 4 shows a second embodiment of the invention. In this instance, like the prior art structure shown in the Japanese Patent Publication SHO 55-37638, the side surface of the tower 1 adjacent to the bottom thereof is provided with a paper-making material extraction port in which a suction pump 21 is mounted. Paper-making material having been diluted by the stirrer 3 is extracted through this extraction port. The entire inner space of each stirring wing 5 of the stirrer 3 constitutes a diluting-water supply passage, and the diluting-water supply ductline 17 is connected to a lower joint box 19. The cylinder 15 and upper joint box 16 in the previous embodiment are unnecessary in this case. As has been described in the foregoing, the structure according to the invention is free from any vertical stirrer support shaft journaled at the tower top center or any driver for rotating such a vertical shaft, so that it is possible to provide the paper-making material inlet near the tower top center. The paper-making material charged into the tower from the inlet thus is substantially uniformly distributed in the tower, thus precluding variations of the load on the stirring wings of the stirrer rotated horizontally in the tower adjacent to the bottom thereof. Further, the downwardly extending shaft for rotating the stirrer may be far shorter than that of the conventional vertical shaft having a height of 10 to 20 m. Owing to this fact and also owing to the substantial freedom from variations of the load on the stirring wings of the horizontally rotated stirrer, the shaft need have only low mechanical strength.

Claims: A paper-making material deposition apparatus comprising a tower (1) having a paper-making material inlet (2) provided at the top for depositing a paper-making material in the inside and a stirrer (3) having stirring wings (5) rotatable in a substantially horizontal plane in and adjacent to the bottom (1') of said tower and having diluting-water jet nozzles (6) and diluting-water supply passages (13) leading to said jet nozzles, said stirrer having an integral shaft (7) depending from the center thereof and penetrating the center of the tower bottom, a driver (12) for rotating said shaft being disposed beneath said tower bottom. The apparatus according to claim 1, wherein each of said stirring wings has a paper-making material suction port (14') open at the leading end thereof, the paper-making material being introduced by suction into the stirring wing via said suction port, passed through the interior of said shaft and taken out of said tower. The apparatus according to claim 1, wherein said diluting-water jet nozzles are provided along the front surface of each stirring wing in the direction of the rotation of the stirring wing. The apparatus according to claim 1, wherein each of said stirring wings has a dual pipe structure, an inside pipe (5') serving as a paper-making material takeout passage (14) and a space defined between the inner surface of said stirring wing and the outer surface of said inside pipe serving as said diluting water supply passage. The apparatus according to claim 1, wherein the inside of each of said stirring wings is divided by a partition member into said diluting-water supply passage and a paper-making material takeout passage.

Inventors: YAMAZAKI, TOKUSHICHI
Applicants: YAMAZAKI, TOKUSHICHI
Application year: 1988
Main classification: D21D5
IPC codes: D21D5, D21C9