US2473269A - Papermaking machine - Google Patents

Description

June 14, 1949. c. s. ADAMS I PAPER MAKING MACHINE Filed sept. 2, 1944 2 seetsfsheet 1 wiiness l Haw-bav C. Cove June' 14, 1949. C, s, ADAMS v 4 2,473,269

y l PAPER MAKING MACHINE` Filed Sept. 2, 1 944 2 Sheets-Sheet 2 2 Snventor Chdrzlies 5. Adams.

witness. I y. l f an Her bevi C. Covcly Gtwmeg Passed .im 14. 1949 UNITED- s'ra'rss 'PATENT orrlcs Y rmnmxma mom Charles 8. Adams, Holden, Mass., an or to Bloc Barton Corporation, Worcester. Mass.. a oorporation of Massachusetts Application september z. 1944, serial No. stam This invention relates to paper making machines and more particularly to a machine of the type in which paper pulp is laid on an endstill air, while the under lside is travelling at" the high wire speed. This causes windage which I tends to orient the stock and straighten out the fibres intov a horizontal alignment. This frictional drag of the air disturbs the formation and travel of the stock materially and should be minimized. Also, the production speed of making the paper is limited by the rate drainage of water from the stock which depends chiefly upon the forcey of gravity plus such effect as is had by the capillary action of the table rolls. Yet, the paper stockshould be laid at a comparatively rapid rate toprevent .reilocculation Ihat is. if the stock remains quiescent relative to the wire, the fibres tend to collect in bunches or to flocculate. It is therefore desirable to lay the fibres rapidly and yet under conditions which cause a satisfactory intermatting thereof. Moreover. the Fourdrinier structure is long, complicated and expensive and occupies a large space in the plant. The wire is also long and comparatively fragile and wears out frequently, and the necessity for frequent replacement thereof requires that the machine lie idle for considerable periods of time.

A primary object of this inventionis to overcome such problems and to provide an efficient paper making machine in which the web is laid.

on a travelling wire screen and which will cause the formation of the paper web at a more rapid rate than heretofore deemed practicable, or which'will accomplish desirable paper making results at lower speeds.

A further object of the inventionl is to provide la machine of this type in which the'water is removed from the stock under pressure greater than that provided by the force of gravity.

A further object is to provide a machine in `which the opportunity for retlocculation of the pulp is materially decreased.

Other objects are to overcome the detrimen-l tal eifectsof windage and to avoid subjecting the stock or the sheet derived therefrom to any 2 frictional drag which would tend to disturb the Paper formation.

Another object is to provide a machine in which the pressure applied to the stock that is. being laid on the wire may be regulated as de- A still further object of this invention is to provide a compact and short paper making machine of simple construction in which the pulp is laid on a travelling wire but wherein that wire is short and comparatively inexpensive and may be readily and quickly replaced. Other objects will be apparent in the following disclosure.

In accordance with my invention, I propose to lay paper stock on an endless travelling wire by forcing the stock under a regulatable pressure into a converging -throat between the wire and an impervious surface of a travelling wall, such as a rotating cylinder, which preferably moves at substantially the same surface rate as that of' the wire and wherein all of the stock introduced into the throat is formed into the web.

Referring to the drawings whichy illustrate preferred embodiments of this invention:

Fig. l is a somewhat diagrammatic vertical transverse section through a machine embodying the principles of this invention and where- :an an endless wire is supported on 'adjustable Fig. 2 is a fragmentary longitudinal section thereof:

Fig. 3 is a detail showing the deckle mounting:

Fig. 4 is a diagrammatic plan of the motor drives:

Fig.` 5 is a. fragmentary transverse section showing a modification wherein the wire is supported on rolls:

' Fig. iil is a sectionaldetail showing the roll Fig. 7 `is a fragmentary vertical section ofva modication having suction boxes supporting the wire; and v Fig. 8 is a longitudinal section through one of the suction boxes and associated parts.

As shown particularly in Fig. 1, a preferred embodiment of this invention comprises a moving endless wire screen Il supported beneath an impervious travelling wall, such as the solid peripheral surface Il of a cylinder i2, which preferably travels at substantially the rate of the wire. 'Ihe wire and the impervious wa1l=are so positioned as to provide a converging throat I3, and pulpstock is introduced into the wide end of the throat from a head box i4 and through a supply nozzle il. The shape of the throat il depends lprimarily on structure .shown in Figs. 1 and 2 comprises a set of wooden slats or bars I8 arranged to form an arcuate wall beneath the cylinder I2. The endless wire I0, which may be made the same as the standard Fourdrinier wire screen, may comprise a iine wire mesh screen of required permeability supportedon a coarser wire mesh or other highly pervious body. v

The wire may be driven in the direction of convergence of the throat, as indicated by the arrows, by means of a power driven roll I8 located at the entrance end of the throat. A roll I9. preferably power driven, is located at the narrow end of the throat and spaced from the surface I I of the cylinder I2 by such distance as is required for the thickness of the web of paper 20, the parts being so arranged as toform a closure for the throat at that end. Further suitably mounted rolls 2|, 22, 23 and 24 serve to return the wire be-v neath the paper forming zone, and suitable provisions may be made in accordance with standard practice for guiding the wire, just as blankets, felts or wires are guided in the paper making industry. The formed paper web may be separated from the wire where the latter bends around the roll 2I.

The nozzle I5 is an elongated pipe of rectangular cross section fitting closely between the surface of the wire as it passes over the roll g I'8 and the outer surface of the cylinder I2, so that the stock may ow into the converging throat I3 under a pressure determined by the head of stock in the head box I4. The stock may be admitted through pipe and the height thereof in the box I4 may be regulated by suitable valve mechanism 26. That is, the top surface 21 of the stock may be raised or lowered by manipulating the inlet valve to obtain the desired pressure within the paper forming throat. The bottom bars I6, which limit the downward movement of the wire and determine the shape of the throat, are mountedabove a vat 28 arranged beneath the paper forming zone to receive the water from the stockpand this water may be suitably removed through an exit pipe 29 located near the bottom of the vat.

The primary yfunction of the cylinder I2 is to provide an impervious upper wall for the space or throat within which the paperweb is formed. 'I'his cylinder, which may be the standard size employed in a cylinder mold machine, may be formed A(Fig. 2) of two end walls 32 supporting a cylindrical wall 33 made of cast iron or other suitable material. The outer periphery II of the cylinder is preferably formed ofhard rubber of suitable composition vulcanized to the iron cylin.. der 33. The cylinder is mounted on trunnions or a shaft'34 carried by suitable adjustable bearings 35 mounted on a portion 36 of the framework of the machine.

'I'he two side walls of the throat I3 may be vformed by two spaced stationary arcuate shaped deckles 40, made preferably of 4hard rubber,

which are so mounted (Figs. 2 andA 3) that the face portions, near the edge, of the travelling wire I 0 and the .ends of the cylinder rub against two faces of the deckles. Various constructions taken from the Fourdrinier machine art may be employed for this purpose. Each deckle may be pushes the deckle inwardly against the adjacent end of the hard rubber layer Il' of the cylinder. Thus, as the cylinder and wiretravel they make a sumciently satisfactory rubbing contact with the deckle t0 prevent any material leakage of the pulp.

Although the bars I5 may be permanently positioned, it is preferable to make them adjustable so that the shape and width of the forming throat I3 may be varied. This may be accomplished, as shown particularly in Fig. 2, by mounting each end of each bar I6 on a slidable post 45. Each post is mounted for sliding radially of the cylinder I2 within a socket in a metal bracket 46 which is suitably secured to an end wall 41 of the vat. 'A screw 48 threaded into the body 46 engages the bottom end of the post 45 and adjustably positions the bar I6 radially of the cylinder. A set screw 49 engages the side of the post 45 and aids in holding the bar I6 immovable. Thus, the bars may be adjusted radially of the cylinder and form an arc of variable length or distance from the cylinder. An angle plate 50 carried by each bar I6 slides against the inner face of the wall 4'I and prevents any material amount of water from escaping at this point. Since the bars I6 are moved radially outwardly and thus spread apart tangentially relative to the cylinder, suitable provisions may be made to close the gaps, except adjacent to the wire, and make a substantially air-tight casing so that, if desired, a vacuum may be applied within the casing to aid in the removal of water from the paper web. Each end bar I6 (Fig. 1) may have attached thereto a slide plate 5I which slides in a radial direction across the top of the vat 28 and thus prevents water from splashing outwardly at this point.

The amount of pulpstock introduced into the throat I3 depends upon the hydraulic head in the box I4 and the rate of withdrawal of paper pulp in the web 20 and the rate of removal of Water. The volume or capacity of the forming throat is determined by the positions of the bars I6. The rate of removal of water from the throat is determined by the pressure and the sizes of the openings between the bars, as well as the influence of gravity and other conditions.

One or more suction devices, such as a suction roll, may be provided at the exit end of the machine to remove further water from the paper web 20. As illustrated in Fig. 1, the roll I8 may machina justably positioned by means of a threaded draw and 55 and it is carried outwardly through an exit pipe 58 suitably connected with apparatus designed to exhaust the air and Water from th roll.

This suction roll I9 may be adjustably mounted a I relative to the periphery of the cylinder I2 by means of a rocking lever support 68 carrying the bearings of the roll. The lever is pivoted at 6I on a bracket carried by the framework 62 of the 'I'he lower arm 63 of the lever is adbar 84 carrying a. hand operated wheel 88 threaded thereon. A spring 88 within a cavity in the frame through which the draw bar passes bears at its opposite ends on the frame and the hand wheel and thus urges the roll I8 under an adinstable resilient pressure towards the cylinder I2 and against the pull of the wire.

In order to adjust the tightness of the wire and to make it readily removable, the roll 24 (Fig. 1) may be mounted on adjustably positioned bearings 12 supported by rods 13 threaded therethrough. Each rod is rotatably supported at its twoends by brackets 14 carried by the machine frame 62, and it is adjustably positioned by means of a hand wheel 18 so arranged that the rod 13 may be threaded through the bearing bracket 12 and thus move the roll 24 up or down as required.

At the left hand end of the machine, a further roll 18 is resiliently and adjustably mounted in position to hold the wire tightly against the driving roll I8. This roll 18 may have each of its bearings 19 suitably mounted on the upper end of a lever 80 pivoted at 8| on a bracket carried by the framework. The lower end of the lever has a draw bar 82 pivotally connected thereto and a spring 83 and hand wheel oi" adjusting nut 84 serve to hold the roll 18 resiliently against the wire, as will be readily understood.

' The operation of this machine involves so positioning and movingv the wire I0 that it will hug the cross bars I6 and not be drawn up against the periphery of the cylinder I2. To this end, I propose to drive the roll I8 at such a rate relative to that of the roll I9 that the rolls tend to hold the Wire somewhat loose within the throat. This may be accomplished by various types of driving mechanism such as an electric motor That is, the roll I8 suitably carried by bearings assembly diagrammatically illustrated in Fig. 4. y

88, is driven through a speed reduction gearing" mechanism 81 by an electric motor 88. Likewise, the cylinder I2 carried on its bearings 35 is driven through a gear reduction 89 by means of an electric motor 90. The roll I9 carried by its bearing support 60 is driven through a gear speed reduction device 9| by4 means of an electric motor 92. The electric motors may be of the direct current constant speed type controlled by rheostats in the field windings. It is to be understood that the gear reduction devices are so constructed that the peripheries of the rolls I2, VI8 and I9 move at the same surface rate. If desired, the electric motor 88 may be so controlled that it attempts to drive the roll I8 at a slightly greater rate than the others soas to insure that the wire hugs the cross bars. This drive may be of the standard sectional electric drive type involved in driving the different rolls of a Fourdrinier paper machine, which comprises synchronous motors and resistance controls so arranged as to move the wire and the cylinder surface at the same rate.

A set of rolls |00 (Figs. 5 and 6) may be substituted for the stationary cross bars I6. In order that these `rolls may be adjustably positioned, their bearings may be mounted substantially the same as the adjustable bars I6. Each of these rolls |00 may have its mandrel |0I supported in a bearing housing |02 carried on a post |05 that is movable radially of the cylinder I2. That is, the post |05 slides in a socket within the bracket |08 mounted on one of the Walls 28 of the vat, and the post is vertically moved by means of thescrew |01 and locked in place by the setscrew |08. Ihe deckle construction is substantially as above described, wherein the sta.- tionary rubber deckle |I0 is carried by the iron bracket I|| mounted on the bearing support |02 so that the deckle will be moved as the rolls |08 are adjusted in position. These rolls |00 carry the Wire I0 without frictional drag since they are freely' rotatable and move with the wire. They also aid somewhat by capillary action in removing water that passes through the wire. The various construction details above described may be incorporated in this modification to provide a vat construction, and if desired, to provide for a partial vacuum to aid in removal of the water.

If a vacuum is to be used for removing water, I may employ the construction shown in Figs. 7 and 8. In this arrangement, a set of suction boxes |20 are adjustably moun-ted on an arcuate frame support I2 I. Each box may be of standard construction used on the Fourdrinier machine. As shown. it comprises walls |22 forming a hollow body closed at its top by a perforated wooden plate |24 having its upper surface shaped in the form of an arc to t substantially against the .travelling wire |0. Each box hasan exit pipe |25 communicating with its interior and leading to a suitable suction apparatus which exhausts the air from the suction box and carries off the water withdrawn from the pulp on the wire. The suction box may be vertically moved by means of a screw |218 threaded into the brackets |2| and engaging the bottom of the box; Further screws |21 carried -by lugs |28 projecting from the side of the box serve to hold the box in position. Thus, by means of these two screws, the box may be moved radially of the cylinder I2 to vary the width of the web forming throat.

The suction boxes may be arranged to form the bottom support for the wire throughout the entire length of the throat I3. Hence, suction may be employed to Withdraw the water from the pulp throughout the entire length of the paper forming Zone as distinguished from the standard. Fourdrinier practice wherein suction is employed only at the dry end of the table section. This aids in further speeding up the formation of the paper web, since I supplement the pressure of the Pulpstock entering the nozzle I5 by the partial vacuum set up within the suction boxes. Thus, the paper is laid on the wire in the short distance of only a few feet represented by less than half of the periphery of the cylinder I2 as compared with the long table section of the Fourdrinier machine.

The operation of the machine will be apparent in view of the above disclosure. Pulpstock is introduced under the pressure of such head as is provided in the head box I4 and this stock flows into the converging throat I3 between the wire I0 and the rubber face I| of the cylinder. The wire and the cylinder are moving at thesame surface rate, and the stock travels at substantially that rate so that there is the minimum of frictional drag on the web at any point. The Water passes rapidly through the openings between the cross bar I6 (Fig. 1) or the rotatable rolls |00 (Fig. 5) or it is removed into the suction boxes |20 of Fig- 7. The water escapes through the wire I0 as the pulp travels towards the narrow end of the throat and the paper web is laid progressively on the wire without undue agitation and without fiocculation. Oneor more suction rolls I9 dry the web sufllciently for its next stage treatment. The taper of the forming zone is such 7 that substantially the entire length of the zone is employed in the removal of water and the laying of the web, and the rate of stock flow is regulated to insure that the forming throat is kept filled with stock. Thus the stock is formed into a web within a tapering cavity whose top and bottom. walls move synchronously. Since the roll I2 has a solid surface that is non-receptive to the paper stock and the wireand its associated supports are perforated, the paper is laid wholly onthe wire and not on the face of the cylinder I2.

In this construction the cylinder has a diameter of from 3 to 8 feet and the arcuate tapering throat extends a considerable distance around that cylinder, such as illustrated. The suspension of pulp in water is preferably introduced at substantially the rate of movement of the wire screen and the opposed cylinder surface, and the shape of the throat is so adjusted relative to the Itype of pulp being treated that the pulp suspension moves forward at substantially that same rate throughout the length of the throat. Hence the pulp is substantially quiescent as regards the 1two adjacent moving surfaces of the cylinder and wire, and there is but little surface drag on the pulp. Consequently, the intermatting of the fibres or the texture of the paper is determined chiefly by the fact that the fibres settle out of suspension onto the adjacent relatively stationary. wire as the `water passes through the latter. The rate of paper making is determined therefore primarily by the speed of movement of the wire and the hydrostatic pressure on the pulp suspension which is involved in gravity and suction. if u sed, and the hydraulic head in the pulp supply box, as well as the centrifugal force set up by the rotatingr cylinder. Thus, the paper is formed on the wire under comparatively quiescent conditions, and it is removed continuously from the paper making zone and thereafter stripped from the wire by the aid 'of the roller |30 adjacent to the return wire roll 2|.

It will now be appreciated that various modifications may be made in the construction and equivalent features substituted for those above described. Also, the paper maker may control the texture of the paper and the rate of its formation by varying the shape of the throat and the head of the puipstock supplied thereto as well as by varying the rates of the moving parts. The above disclosure is, therefore, to be interpreted as illustrating the principles of this invention and my preferred embodiments thereof and not as imposing limitations on the claims appended hereto.

I claim:

1. A paper making machine comprising a moving, endless, pervious, fine mesh Screen wire arranged for the formation thereon of a paper web deposited from an aqueous suspension of paper pulp stock, a traveling wall located only above and opposed to the wire in a relatively fixed relationship which is impervious and non-receptive to the paper stock, means for movably supporting the wall, a fixed support which predetermines the configuration of the wire and provides for the passage of water therethrough, side walls adjacent to the edges of the Wire, said wire and walls forming a gradually tapering throat of fixed and predetermined shape which converges from a wide stock entrance to a closed end where the paper web on the wire contacts with the traveling wall, controllable driving mechanism for moving both the wire and the traveling wall at the same rate towards the closed end of the throat without disturbing the throat shape, means for removing the water that has passed through the wire, and regulatable means including a conduit that makes a substantially water-tight connection with said entrance for maintaining the throat filled with an aqueous paper stock suspension under a controlled hydraulic head which determines the rates of water removal and paper formation, the throat providing for the progressive concentration of a suspension of pulp fibres and the formation of a paper web on the wire by the forced removal of the water during the period of travel of a portion of the Wire and the associated pulp from the entrance to the closed end of the throat.

2. A paper making machine comprising a rotatable cylinder having an impervious, non-receptive, peripheral surface mounted to rotate about a horizontal axis; an endless, pervious; moving screen wire arranged substantially wholly beneath the cylinder for the formation thereon of a paper web deposited from an aqueous suspension of paper pulp stock, a fixed support providing a free passage of water therethrough which holds the wire in a predetermined arcuate shape around and spaced from the lower portion of the cylinder periphery and forms a tapering throat of fixed configuration converging from a wide stock entrance to a closed end where the paper web on the wire contacts with the cylinder, walls forming the sides of the throat, means in- 'cluding a conduit making a substantially watertight connection with said stock entrance for maintaining the throat filled with a paper stock suspension under a variable vhydraulic pressure which forcibly removes the water and controls the rate of paper formation, said throat being shaped to provide space for freely floating paper fibres which become intermatted gradually and form a web on the Wire as the Water is forced through the Wire, means for rotating the cylinder, means for moving the wire at the peripheral rate of the cylinder and in the same direction towards the closed end of the throat without changing the configuration of the throat materially and means for removing the water that drains through the wire.

3. A paper making machine comprising an endless, pervious, moving screen Wire arranged for the formation thereon of a paper web deposited from an aqueous suspension of paper pulp stock, rolls having horizontal axes which support the wire, a traveling wall spaced above the Wire which is impervious and non-receptive toA the paper stock, adjustable means for maintaining the wall and the moving wire in a fixed relationship and forming a tapering throat of predetermined shape which converges from a Wide stock entrance to a closed end Where the paper web on the Wire contacts with the Wall, driving connections for moving both the wire and the wall at the same rate towards the closed end of the throat Without changing the throat configuration,l means for removing the Water that has passed downwardly through the wire, controllable means including a conduit that makes a substantially water-tight connection with the throat entrance for maintaining the throat filled with a paper stock suspension under a variable hydraulic pressure which determines the rate cf pulp stock movement and suction means for removing water from the paper on the wire web as it leaves said throat, the taper and dimensions of the throat being related to the permeability of the wire so that a suspension of freely iioating bres becomes concentrated in said throat and the libres are laid as a paper web on said wire during their passage through the throat.

4. A paper making machine comprising a rotatable cylinder having an impervious, non-receptive peripheral surface mounted to rotate about a horizontal axis, an endless, pervious, moving screen wire mounted in an arcuate shape beneath the cylinder and arranged for the formation thereon of a paper web deposited from an aqueous suspension of paper pulp stock, a set of spaced, adjustable supports beneath the wire lwhich predetermine the conguration of the throat and provide for the drainage of water therefrom, side walls, said cylinder, wire and side walls forming a. tapering, arcuate throat converging from a wide stock entrance at one side of the cylinder to a closed end at the other side where a paper web laid on the wire contacts with the cylinder periphery, means for moving the wire towards the closed end of the throat at a rate which maintains the pulp suspension quiescent, means for rotating the cylinder in the same direction and at the same peripheral rate, means includinga conduit that makes a substantially water-tight connection with said entrance for maintaining the throat lled with said pulp stock suspension under a regulatable hydraulic head which controls the rates of water removal and paper 4formation and causes the water to move substantially at the rate of wire movement, means for withdrawing water from beneath the wire and means for supporting the formed paper web outside of said throat and removing water therefrom, the throat structure providing for the progressive concentration of said suspension at a rate determined by the hydraulic head and 10 the deposition of all of the pulp on the wire as it moves with the pulp through the throat.

5. A paper making machine according to claim 2 in which the xed support for the wire comprises rollers beneath the wire which are adjustably mounted for movement towards and from the cylinder axis.

6. A paper making machine according to claim 2 comprising suction means for reducing the atmospheric pressure beneath the wire where it forms a wall of the throat and thus aiding the hydraulic pressure on the stock Within the throat to hasten the water removal.

CHARLES S. ADAMS.

` REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Great Britain Oct. 23, 1930

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