US2396587A - Apparatus for producing pulp - Google Patents

Description

Mmwch E2, 1%45. K A u LQWGREN AL 2,395,537

APPARATUS FOR PRODUCING PULP Filed Marchzo, 1941 4 Sheets-Sheet 1 K. A. u. LQWGREN E AL, APPARATUS FOR PRODUCING PULP Filed March 20, 1941 4 Sheets-Sheet 2 TOR.

A. u. LQWGREEN ET AL. 2;55? APPARATUS FOR'PRODUCING- PULP 4 Sheets-Sheet 5 Filed March 20, 1941 March 12, 1946.

K. A. u. LOWGREN ETAL 2,396,587 APPARATUS FOR PRODUCING PULP Filed March 20, 19,41 4 Sheets-Sheet 4 58 ,54' a/ I I Patented Mar. 12, 19 46 APPARATUS ron PRODUCING PULP Karl Assar Uno Lowgren, Tarrytown, and Al! Adolf Alfsen, New York, N. Y., and Hjalmar S. Messing, New Orleans, La., assignors to, American Defibrator, Inc., New York, N. Y., a corporation of Delaware Application March 20, 1941, Serial No. 384,280

4- Claims.

Our invention relates to apparatus for the production of pulp, and more particularly to apparatus adapted for use in conjunction with an Asplund defibrator. v

As is shown in Asplund Patent No. 2,145,851, issued February 7, 1939, defibrating apparatus of this type includes a mechanical grinding device which is enclosed in a pressure type container to which is admitted steam under suitable pressure. Means are provided for continuously feeding the material to be treated, for in-' stance, in the form of wood chips, without loss of steam pressure, as well as means for discharging the defibrated material from the casing without loss of pressure. As is disclosed in the above patent, as well as in Asplund Patent No. 2,008,892, issued July 23, 1935, the heating of the material to a suitable temperature results in an apparent melting or softening of the substance which binds the fibres together, known as the middle lamella, and this in turn greatly facilitates the separation of the fibres by mechanical v grinding. It not only reduces very materially the amount of power required, but also permits the fibres to be substantially separated from each other with a minimum of damage to the individual fibres.

As disclosed in the aforesaid Asplund patents, the material in the form of wood chips or the like is fed to the grinding discs through a pressure-tight path, the length of which is such that the material is subjected to the steam only long,

enough to bring the material up to the temperature of the steam. In practice it has been found that a period of less than a minute is suificient for this purpose.

It has subsequently been determined that certain additional advantages are obtained if the material is heated for a substantially greater length of time before being subjected'to mechanical grinding, and still other advantages are obtained if the material is treated with certain chemicals during such prolonged heating, and the present invention relates to improved apparatus for this purpose.

One of the objects of our invention is to provide as compact an apparatus as is possible, while still having the desired capacity. Another object is to provide an apparatus of this type which may be readily connected to an existing Asplund defibrator with minimum structural alterations in the plant. In order to obtain the maximum capacity from a device of given size it is essential that the device be filled as completely as possible with the material to be treated, and

tion will be apparent from the following descrip-v tion considered in connectio'n with the accompanying drawings which form a part of this specification and of which;

Fig. 1 is a top view of oneembodiment of our invention connected to an Asplund defibrator;

Fig. 2 is a cross=sectional view on an enlarged scale taken on the line 22 of Fig. 1;

Fig. 3 is a top view of another embodiment of our invention;

Fig. 4 is a cross-sectional view on an enlarged scale taken on the line 4-4 of Fig. 3;

Fig. 5 is a top view of a still further embodiment of our invention;

Fig. 6 is a top view of a fourth embodiment of our invention;

Fig. 7 is a cross-sectional view taken on the line 'l-'l of Fig. 6;

Fig. 8 is atop view of a fifth embodiment of our invention;

Fig. 9 is a cross-sectional view taken on the line 9-9 of Fig. 8;

Fig. 10 is a top view of a sixth embodiment of our invention;

Fig. 11 is a cross-sectional view taken on the line il-ll of Fig. 10;

Fig. 12 is a side view, partially in cross-section, of a seventh embodiment of our invention; and

Fig. 13 is a top view of a portion of the device illustrated in Fig. 12.

Referringmore particularly toFigs. l and 2. reference character I0 designates generally a feeding apparatus, while reference character H designates generally an Asplund defibrator. The feeding device Hi includes an electric motor 12 which drives through a gear box I3, a helical screw M which is located within a casing i5 and which extends into a member I6 formed with a conical bore 5?. The'portion of the screw M which is disposed within the conical bore is correspondingly conical. Casing I5 is formed with an opening l8 at the top with which communicates a chute or the like is which serves to feed the material by gravity.

The defibrator l I includes a pressure-tight casing 20 into which extends a shaft 2| which carries a grinding disc 22. Shaft 2| is connected to theshaft of an electric motor 23. Closely adjacent to disc 22 is a stationary disc 24 formed with a central aperture which is in alignment with a conduit 26 which forms an inlet to the casing 20. Communicating with casing 20 at a point at its periphery is an outlet conduit 26 which is provided with a pair of discharge valves 21 and 28. These valves are operated by means of a mechanism 29 in such a manner that one valve is open while the other valve is closed to thereby form a pressure lock. Conduit 26 discharges into a suitable receptacle 3!).

A steam balance line 3| communicates with the interior of casing 26 beyond the peripheries of the discs 22 and 24 and with the inlet conduit 25. As shown in Fig. 2, conduit 3| communicates with a pocket 32 formed in conduit 35 which opens toward the casing 20 so that it will not become clogged with solid material moving through the conduit. Steam under suitable pressure is supplied to conduit 3| by means of a steam line 33.

Connected between the feeding device l and the deflbrator II is a treatment chamber designated generally by reference character 34. As

shown particularly in Fig. 2, this chamber includes a conduit 35, the right hand end of which is formed with a cylindrical bore 36 having a diameter equal to the minimum diameter of the conical bore [1. The remainder of conduit 35 is formed with a conical bore 31, the minimum diameter of which is somewhat greater-than the diameter of bore 36, so as to provide an abrupt shoulder 38 at the point of juncture. If the diameter of bore 36 is the minimum diameter of bore 31 should be about /2" greater and its diameter should increase at the rate of between A" and V4" per foot of length. The length of conduit 35 is determined by the length of time it is desired to subject the material to treatment, having regard to the rate of flow of the material through the conduit.

A steam line 33 is provided for the admission of steam, the pressure of which should be substantially the same as that. in line 33. A conduit 4|! serves for the admission of suitable chemicals, preferably in liquid form. Conduit 35 may be enclosed within heat insulating material 4|.

The above described apparatus operates as follows:

Material to be treated, for instance in the form of wood chips, is fed to casing through the chute l9. Rotation of screw l4 in the proper direction propek these chips into bore 11 and, due to the conical nature of this bore, the chips are compacted into a substantially solid mass which prevents the escape of steam. The solid mass of chips is advanced through bore 36 and when the mass reaches the shoulder 38 it is able to expand and break up so that the surfaces of the chips are exposed and may be acted upon by the steam admitted through line 39 and the chemicals admitted through conduit 40. The rate of admission of the chemicals is preferably so regulated that substantially all of the chemicals are absorbed in the wood and consequently there is little, if any, free liquid present within the conduit 35. The steam serves to heat the wood to thereby soften the middle lamella and also to increase the chemical reaction.

The chips are advanced through the conduit 35, the .conical bore 31 permitting them to expand under the action of the steam and chemicals without binding. We have determined that the bore 31 may be substantially completely filled with chips, thus utilizing to the fullest extent the capacity of the treatment chamber, without requiring an excessive amount of power for propelling the chips, and without the necessity of providing a screw conveyor or the like within the bore 31.

The chips, after having been subjected to the heat and chemical treatment within the chamber 34, are fed through the conduit 25 to the discs 22 and 24. The disc 22 is set close to the disc 24 and the chips are forced to pass between these relatively rotating discs. In well known manner the fibres making up the chips are separated from each other and are discharged through the conduit 26 and the valves 21 and 28 to the receptacle 30. It will be noted that the entire device from the plug formed in the bore 11 to the discharge valves is under steam pressure and the grinding takes place under such pressure.

In the embodiment illustrated in Figs. 3 and 4 the feeding device III is located beside the defibrator ll, instead of in axial alignment therewith, and at a somewhat higher elevation. The

' treatment chamber 34a is curved through an arc of and instead of being connected directly to the inlet of the casing 20 it communicates with the side of a vertically extending receptacle 45. The bottom of this receptacle is connected to an inlet conduit 2541, within which is provided a screw conveyor 46 for feeding the chips from the bottom of the receptacle 45 to the discs within the casing 20. Conveyor 46 is driven through a chain drive 41 by means of an electric motor 46.

The operation of this embodiment is substantially the same as that shown in Figs. 1 and 2. However, the arrangement is such that the apparatus is much more compact and may hence better accommodate itself to an existing plant layout.

The embodiment illustrated in Fig. 5 is similar to that disclosed in Figs. 3 and 4, with the exception that the receptacle 45 and screw conveyor 46 are omitted, and the 3417 is curved through an arc of so as to communicate directly with the inlet 25b of the casing 20. Due to the conical bore of the treatment chamber, as well as to the fact that it is inclined downwardly from the feeding device id to the casing 20, the screw H of the feeding device is able to propel the material through the curved path without requiring other propulsion means.

In the embodiment illustrated in Figs. 6 and '1 the treatment chamber 340 includes a'conical portion 50 curved through an arc of 90, a straight cylindrical portion 5! and a cylindrical portion 52 curved through an arc of 90. As shown particularly in Fig. '1 portions 50 and 5! are not in axial alignment, but the former communicates with the upper side of the latter. A screw conveyor 53 is disposed within the straight cylindrical portion 5! and is driven through a chain drive 54, a shaft 55, bevelled gears 56 and a shaft 51 from the motor 12 of the feeding device l0. Thus, the relation between the speed of the screw l4 and the conveyor 53 remains constant, which is desirable inasmuch as both of these members handle the same quantity of material. In this embodiment, a longer path of travel through the treatment chamber is obtained, thus increasing the duration of the treatment, or making it possible to increase the rate treatment chamber upwardly inclined so as to communicate with the upper part of a receptacle 45, which is similar to that illustrated in Figs. 3 and 4.. A'screw conveyor 46 serves to transfer the material from the bottom of receptacle 45 to within the casing 28 of the defibrator. N

As the mass of chips enters the receptacle 88 from the feeding device It! it becomes separated as the chips fall to the bottom of the receptacle.

Thereafter, as the chips are propelled by the conveyor 82 through the conduit 8| of decreasing diameter, they ar compacted somewhat so that when they enter the chamber 34d they occupy less space than would otherwise be the case. Consequently, more chips may be accommodated in the chamber 3411, thus increasing the time the chips remain in the chamber.

In Figs. 10 and 11 there is shown an embodiment of our invention which is particularly well adapted for use in connection with a defibrating apparatus which has previously been installed. As here illustrated, the treatment chamber comrises two portions. The first portion consists of a conical curved conduit 65, the smaller end of which is connected to the feeding device l0. Steam line 38 and conduit 88 for the introduction of chemicals communicate with conduit 65.

The other portion of the treatment chamber includes two horizontal cylindrical chambers 65 and 81 mounted together one above the other on a truck 68. One end of chamber 66 communicates with a vertical receptacle 68 to the side or which is connected the larger end of conduit 65. The other end of chamber 86 communicates through a vertical passage 18 with one end of chamber 81. The opposite end of this chamber is extended and connected 'to the inlet of casing 20.

Screw conveyors H and 12 are disposed within chambers 66 and 61, respectively, and are connected together by means of gears 13 so as'to be driven in opposite directions by means of a motor 14. As shown in Fig. 11, only a portion of the shaft of conveyor 1| is provided with a continuous spiral, the remainder having thereon inclined lugs 75 which may be termed an interrupted screw, and which serve chiefly to agitate the material in this portion of chamber 68. The interrupted screw results in this portion of the chamber 66 being more completely filled with chips than would be the case if an ordinary screw were employed. This in turn increases the eiiective capacity of the chamber. A steam balance line 3| connects receptacle 69 with casing 28.

In this embodiment the screw M of the feeding device it serves to propel the material through the curved conical conduit 65 to the receptacle 89. From this receptacle the material drops by gravity into one end of chamber 56 and it is propelled through this chamber and through chamber 67 to the casing 28 of the defibrator by means of the conveyors H and 12.

The embodiment illustrated in Figs. 12 and 13 is particularly well adapted for providing the maximum period of treatment while utilizing a minimum amount of floor space. As here shown, the treatment chamber includes a conical conduit portion and a comparatively large vertical chamber 8| The smaller end of the conical conduit is connected to thefeeding device In, while the upper and larger end of the conduit is connected to the upper end of the receptacle 8|. This chamber is somewhat conical, being of greater diameter at the bottom than at the top. A rotary table 82 is provided at the bottom of diameter 8| and serves to move the chips into a trough 83. A screw conveyor 84 is located in this trough and conveys the chips to the inlet 25 of the defibrator casing 20. A scraper 84 is also arranged to help the discharge of the chips from said table 82 into the screw conveyor 84. Table 82 is driven by an electric motor 85 through bevelled gearing .86 and a vertical shaft 81, while conveyor 84 is driven by a motor 88 througha chain transmis sion 88. The chamber 8|, together with the mo-.

tors 85 and 88 and the transmission'mechanism is advantageously mounted on a truck 80. The top of chamber 8| may be connected to casing 28 through a steam balance line 8|". Apivoted vane 9| is disposed within the upper part0! diameter 8| and is connected by means of a shaft 82 with an indicator 93 outside the chamber. 'I'he purpose of this device is toindicate the upper level of the chips in the chamber, and if it increases so as to raise the member 9|, and hence I the indicator 83, the speedof rotation of the table 82 is increased by the operator so as to discharge chips into the trough 83 at a faster rate.

In this embodiment the screw ofv the feeding device l0 serves to propel thejchips upwardly through the conical conduit Bil-and into the chamber 8|. This chamber has a substantial capacity and hence may accommodate a comparatively large quantity of chips, thus prolonging the time during which the chips remain in the chamber, and consequently prolonging the period of treatment.

While we have shown and described several embodiments of our invention, it is to be-under stood that this has been done for purposes of illustration only, and that the scope of our in vention is not to be limited thereby, but is to be determined by the appended claims.

What is claimed:

1. In apparatus for producing pulp, a conduit of substantial length having a conical bore, means for feeding material to be treated into said conduit, said bore increasing in diameter away from said feeding means, means for introducing steam into said conduit adjacent to its smaller end, an abrading means, means forming a chamber of substantial volume and vertical extent, said conduit communicating with the upper end of said chamber, a rotary table at the bottom of said chamber, a trough below said table for receiving material discharged from said chamber by said table, and means for conveying the material from said trough to said abrading means, said conduit, feeding means, chamber and. abrading means being constructed to maintain fluid pressure well above atmospheric.

2. In apparatus for producing pulp. a conduit, means for feeding material to be treated into said conduit, an abrading means, means forming a conical chamber of substantial volume and vertical extent, the larger end of said chamber being at the bottom, said conduit communicating with the upper end of said chamber, a rotary table at the bottom of said chamber, a trough below said table for receiving material discharged from said chamber by said table, and means for conveying the material from said trough to said abrading means, said conduit, feeding means, chamber and abrading means being constructed to maintain fluid pressure well above atmospheric:

3. In apparatus for producing pulp, a conduit of substantial length, means for feeding material to be treated into one end of said conduit, means for introducing steam into said conduit adjacent to said feeding means, means forming a chamber of substantial vertical extent, the other end of said conduit communicating with the upper end of said chamber, an abrading means, a rotary table at the bottom of said chamber, a trough below said table for receiving material discharged from said chamber by said table, and means for conveying the material from said trough to said abrading means, said conduit, feeding means, chamber and abrading means being constructed to maintain fluid pressure well above atmospheric.

4. In apparatus for producing pulp, a conduit, means for continuously feeding material to be treated into said conduit, abrading means, means forming a chamber oi substantial volume and vertical extent, the major portion of the interior of said chamber constituting unoccupied space and the major dimension of said chamber extendin in a vertical direction, said conduit communicating with the upper end of said chamber, a rotary disc at the bottom of said chamber, a trough below said disc for receiving material discharged from said chamber by said disc, and means for conveying the material from said trough to said abrading means, said conduit and feeding means and chamber and abrading means being con structed to maintain fluid pressure well above atmospheric.

' KARL ASSAR UNO LOWGREN.

ALF ADOLF ALFSEN. HJALMAR S. MESSING.

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