US1903151A - Apparatus for feeding pulp or fiber to paper making machinery - Google Patents

Description

March 28, 1933. A. e. WAKEMAN 1,903,

APPARATUS FOR FEEDING PULP OR FIBER TO PAPER MAKING MACHlNERY Filed April 23 1932 Patented Mar. 28, 1933 PATENT OFFICE ARTHUR G. WAKEMAN, F APPLET ON, WISCONSIN APPARATUS FOR FEEDING PULP OR FIBER TO PAPER MAKING MACHINERY Application filed April 23,

My present invention relates to improvements in apparatus for feeding pulp or fiber to paper making machinery. Such pulp or fiber is usually in a finely comminuted condition and'is carried to the paper making machinery suspended by agitation in a relatively large volume of Water. The amount of pulp or fiber which is delivered to the paper making machinery depends upon the amount of fiber which is in a given quantity of water, or the consistency ofthe mixture of water and fiber contained therein, and the amount of the mixture which is delivered to the paper making machinery. The amount of mixture '15 which is delivered to the paper making machinery may be easily controlled by a gate or other suitable valve controlling the flow. The control of the consistency of the mixture is a somewhat more intricate problem and has heretofore been approached in different ways, but, so far as I am aware, no one has yet employed, or suggested, centrifugal separation in maintaining a uniform mixture or consistency of pulp and water for feeding to paper making machinery.

I have found that the rotor, or rotating element, of a centrifugal separator may be built, by suitably baffling or delaying the movement of the denser portion of its con tents, so as to secure a wide range of degrees of separation or concentration of the mixture, whereby a desired concentration or consistency of the mixture may be uniformly secured from mixtures of varying consistency, except that there should always be more than the desired amount of water in the mixture submitted or fed to the separator. The dependability and uniformity of the" action of the centrifugal concentrator is increased by maintaining the consistency of the mixture fed to it within as narrow limits of variation as is practicable and for this purpose I have employed mechanism also involving a centrifugal separator.

If the pulp or fiber is'not, and does not remain, homogeneously distributed through-' out the water of the mixture, an agglomeration is likely to occur when a gravitational feed is alone relied upon in feeding the mixture to the paper making machinery, and

1932. Serial No. 607,042.

when agglomeration occurs unevenness of feed is unavoidable.

As will hereafter be seen, my centrifugal separatlon or concentration of the mixture of water and pulp or fiber prevents any tendency to agglomeration and is particularly important in the feeding of paper stock in which the fibers are relatively long.

I have attained the foregoing objects and results by means of the apparatus illustrated 60 in the accompanying drawing, in Which Flg 1 1s a schematic elevation, partially 1n section, of an arrangement of mixing box, consistency controlling apparatus and centrifugal feed embodying my invention; and

Flg. 1s a fragmental plan of the structure shown in Fig. 1.

In connection with my invention I have employed the usual form of mixing box now generally used in feeding stock' to paper making apparatus, which mixing box com- RIISQS a chamber or receptacle 5 of suitable snze or capacity, which receptacle is provided with a longitudinal partition 6 extendin from the bottom to a suitable distance be neath the top. Extending between the partition 6 and one side wall of the receptacle 1s a transverse partition 7 which extends from the bottom of the receptacle to the top thereof or to asultable distance above the top of the partltion 6. The partition 7 provides in the receptacle upon one side of the partition I Gan entering compartment 8 and an overflow or return compartment 9. Connecting with the entering compartment 8 is a feed pipe 10 through which pulp or fiber and water is pumped into the receiving compartment 8 from which it overflows into the mixing compartment 11 until the mixing compartment is filled to the height of the, partition 6, after which any excess flows into the overflow or return compartment 9 and from the return compartment 9 runs a pipe 12 to the tank or receptacle from which the pump getsits supply. Discharging into the compartment 11 is a water conduit or pipe 13 and it is the usual practice to govern, or try to govern, the flow through the pipe 13 so as to secure the desired consistency or concentration of pulp or fiber and water in the compartment 11.

It will now be seen that the chamber or receptacle 5 not only constitutes means for changing the consistency of the mixture but also provides apparatus for maintaining a constant level or uniform hydrostatic head in the feeding mechanism. In one end of the chamber 11 is provided a port 14 controlled by an adjustable gate 15. (lo-operating with the port 14 is a gutter or channel or suitable conduit 16 for delivering the mixture to the central feed pipe 17 of my centrifugal separator or concentrator.

The centrifugal separator or concentrator consists of arotor 18 mounted upon the top of a vertical spindle 19. Any suitable mechanism, several forms of which are well known, may be employed for rotating the spindle 19. The rotor may be of a desired form or structure so as to delay the delivery of the concentrated portion of the contents thereof sufficiently to secure the desired concentration. I prefer, for simplicity, to give my rotor a cylindrical form with a closed bottom and open top. Extending inwardly from the vertical walls or the rotor are a number of annular, spaced baffle plates 20. which baflle plates at their point of juncture with the vertical walls of the rotor are provided with spaced perforations 21. The top baflie plate 20 has an extension from its inner edge extending upwardly, as at 22, and then outwardl v, as at 23. Supported in any suitable manner so as to have their tops substantially level with the top of the rotor are an inner and outer annular channel 24 and 25. The outer wall of the inner channel 24, which is the same as the inner wall of the outer channel 25, is extended, as at 26, to enter between the top of the rotor 18 and the extension 23, and the outer wall of the channel 25 is extended, as 27, to a suitable distance above the extension 23 of the rotor. The degree of concentration secured by the rotor depends upon the number of bafiies and the width of the baflles and the size and number of perforations in the baflles so that by suitably relatin these elements a desired concentration of a1? mlxture of water and pulp or fiber may be secured and maintained. I

The influx of fresh material through the feed pipe 17, together with the movement of the rotor, secures a concentration of the mixture at the sides of the rotor which is forced up through the perforations and is discharged over the rim of the rotor under the extension 26 into the channel 24 while the less concentrated portion of the mixture travels up inside of the bafiles and over the top of the extension 23 where it is thrown between the extensions 26 and 27 into the channel 25. A conduit 28, leading from channel 24, may be taken directly to the paper making machinery,

or, to permit of a simple method of changing the base weight of the product without the necessity of providing a different rotor. The conduit 28 may be led into the receiving compartment of a level maintaining box 29, similar in construction and operation to the mixing chamber or receptacle 5, from the discharge chamber of which the mixture may be permitted to flow by means of a controlled valve 30 through a conduit 31 to the paper making apparatus. In this way a single rotary concentrator may be employed, and, neverthe ess, the base weight of the product controlled by merely controlling the delivery by means of the gate 30 through the pipe 31 to the paper making apparatus. A conduit or conduits 32 leading from the channel 25 conveys the mixture from channel 25 back to the stock tank from which it was originally pumped.

While the apparatus heretofore described secures an eflicient and practical control of the consistency of the mixture of water and pulp or fiber fed to the paper making apparatus, nevertheless, a more exact and refined control of the base weight of the product may be secured by maintaining the consistency of the mixture fed to the rotor between relatively small limits of fluctuation. For this purpose I provide a port 33 in the compartment 11 opposite to the port 14, which port is likewise controlled by a gate 34. The discharge from the port 33 is conveyed by channel or conduit 35 to the center feed pipe of a centrifugal separator 36. In this case, however, the concentrated portion of the material from the separator is led back into the return 12 by conduit 37, while the water from the separator is led by conduit 38 to a float tank 39 which is provided with a drain 4O controlled by an adjustable valve 41 and an overflow 42. A baffle 43 is provided in the float tank so as to reduce and practically prevent the disturbance of the float 44 by and through the discharge from the pipe 38.

If the proportion of water in tank 11 increases, a greater amount of water is separated in the separator 36 and is conveyed through the pipe 38 into the float tank 39 and float 44 rises, and conversely, if the proportion of water in the compartment 11 decreases, less water is extracted in the separator 36 and the float 44 descends. This action, of course, is postulated on the adjustment of the valve 41 to discharge from the float tank the amount of water extracted when the mixture is at a desired consistency.

Different forms of apparatus may be employed which will be responsive to the rise and fali of the float 44 for securing a change of consistency in the compartment 11. For this purpose I have illustrated, and will describe, a standard form of such apparatus.

Inter-posed in the water pipe 13 is a valve 45, the stem 46 whereof is threaded and on the end of the stem 46 is provided a wheel 47 upon the opposite faces of which are cut ratchets. A wheel 48 is rotatably mounted above and at right angles to the ratchet wheel 47, the edge whereof is provided with worm engaging teeth, which co-act with a worm 49 continuously driven by a motor 50. A crank pin 51 is provided in the face of the Wheel 48 from which depends a crank arm 52 the lower end whereof is bifurcated to straddle the ratchet wheel. 47. Pawls 53 are provided upon each of the bifurcated ends of the crank arm and a rocking saddle 54 is mounted on the valve stem 46 and attached by a connecting rod 55 with the float 44. The rocking saddle 54 is also attached to one of the lower bifurcations of the crank arm 52, whereby when the float 44 is in normal position, the pawls 53 are out of co-action with the ratchet 47, but when the float 44 rises, the pawl upon one side of the ratchet is brought into co-action with the ratchet, and when the float 44 sinks below normal, the opposite pawl is brought into co-action With the other side of the ratchet, thereby either opening or closing the valve 45 and feeding to the compartment 11 a greater or less amount of water.

It will be noticed that none of the operations of my apparatus tend to slow up the normal gravitational flow of the mixture therethrough, but rather to increase the turbulency of the mixture, which is important in preventing agglomeration, and particularly so when pulp or fiber of relatively long lengths is employed.

Having described my invention what I claim as new and desire to secure by Letters Patent is:

1. Mechanism for feeding pulp or fiber to paper making machinery comprising a chamber for mixing pulp stock or fiber and water and water, a conduit leading from said mixing chamber, a receiving tube co-operatively related with said conduit, a rotor for generating centrifugal action axially related with said receiving tube, baffles associated with said rotor, annular chambers co-operating with said baffles to respectively receive the baflled and unbaflled discharge from said rotor, and conduits leading from said respective annular channels to a paper making machine and the stock supply for saidmixing chamber.

2. Mechanism for feeding pulp or fiber to paper making machinery comprising a chamber for mixing pulp stock or fiber and water and water, a rotor for generating centrifugal action, means for feeding a controlled supply of the mixture from said mixing chamber to said rotor, baflles associated with said rotor, annular chambers co-operating with said battles to respectively receive the baflled and unbaffled discharge from said rotor, and

lar channels to a paper making machine and the stock supply for said mixing chamber.

3. Mechanism for feeding a desired consistency of a mixture of substances of different ravit one whereof is fluid com risin b respectively receive the baflfled and unba-ffled discharge from said rotor, and conduits leading from said respective annular channels.

4. Mechanism for feeding a desired consistency of a mixture of substances of different gravity, one whereof is fluid, comprising a chamber for mixing said substances, a rotor for generating centrifugal action, means for feeding a controlled supply of the'mixture from said mixing chamber to said rotor, baffles associated with said rotor, annular chambers co-operating with said baflles to respectively receive the baflled and unbaflied discharge from said rotor, and conduits leading from said respective annular channels, means for controlling the mixture in said mixing chamber'within known limits of consistency comprising means for supplying materials including a fluid feed supply to said mixing chamber, a control valve interposed in said fluid supply means, an auxiliary conduit from said mixing chamber, a centrifugal separator interposed in said conduit, a float tank associated with said centrifugal separator so as to receive the fluid discharged therefrom, a float in said tank, and means responsive to the movement of said float for controlling said valve.

5. In mechanism for feeding a desired consistency of a mixture of substances of different gravity, one whereof is fluid, a mixing chamber, means for controlling the mixture in said mixing chamber within known limits of consistency comprising means for supplying materials including a fluid feed supply to said mixing chamber, a control valve interposed in said fluid supply means, an auxiliary conduit from said mixing chamber, a centrifugal separator interposed in said conduit, a float tank associated with said centrifugal separator so as to receive the fluid discharged therefrom, a float in said tank, and means responsive to the movement of said float for controlling said valve.

ARTHUR G- WAKEMA N.

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