US2392150A - Suction roll helper drive - Google Patents

Description

Jan. 1, 1946. HORNBOSTEL ET AL 2,392,150

SUCTION ROLL HELPER DRIVE Filed May 20, 1942 3 Sheets-Sheet l Z ZZZ'EZ 2:71 E

14 01 0. fi aemsosrz-L [Ton 480 .0. BEACHLEQ.

Jan. 1, 1946. L. HORNBOSTEL ET AL 2,392,150

SUCTION ROLL HELPER DRIVE Filed May 20, 1942 3 Sheets-Sheet 2 Layo flOE/VBOSTEL fbw/zea 0, EEACHLEE. M M M 2 E Patented Jan. 1, 1946 SUCTION ROLL HELPER DRIVE Lloyd Hornbostel and Edward D. Beachler, Beloit Wis., assignors to Belolt Iron Works, Beloit,

Wis., a corporation of Wisconsin Application May 20, 1942, Serial No. 443,680

10 Claims.

This invention relates to suction roll drives controlled by the degree of vacuum in the driven suction rolls.

Specifically the invention relates to paper making machines having a main couch roll driven forming wire, a primary suction couch roll engaging the wire in advanc of the main couch roll, and a helper drive for the primary suction couch roll driven by the main couch roll drive and automatically operating in accordance with the degree of vacuum in the primary suction couch roll.

In accordance with this invention a Fourdrinier type paper making machine having a looped forming wire driven by a main couch roll within the loop of the wire is equipped with a primary suction roll for acting on paper stock on the forming wire in advance of the main couch roll, This primary suction couch roll is disposed within the loop of the paper machine forming wire and has a suction area acting on stock deposited on the wire to extract liquids from the stock so that a more dehydrated web can be delivered from the forming part of the paper machine. primary suction couch roll includes a rotating perforated shell in engagement with the forming wire. In order to prevent slippage between the rotating shell and the wire it is necessary to drive the shell at the wire speed. Since the main couch roll drives the wire, it is convenient to drive the primary suction roll from the main couch roll, However, the power input to the primary suction couch roll must var independently of the speed of the main couch r011 because the forming wire is actually somewhat elastic and will stretch at areas of great tension and contract at areas where this tension is released. In paper machines of this invention the forming wire tension just ahead of the primary suction couch roll is maximum because, at this point, the primary suction couch roll is pulling or dragging the wire over the stationary suction Gil This

boxes which are conventionally positioned under a As a result 01' these conditions, it is not possible to use a fixed type of drive for both the main couch and the primary couch and, in accordance with this invention, a helper type of drive is used for driving the primary couch.

This helper type or drive is, according to this invention, automatically controlled to vary the power input to the primary suction couch roll in accordance with the degree of vacuum maintained in the suction area of that roll. If no driving efiort is imparted to the primary suction couch roll, its rotatable shell will, of course, impart a frictional drag to the wire, thereby damaging the wire by frictional wear. If, on the other hand, a large power input is supplied to the primary couch, the rotating shell thereof will spin faster than the speed of the wire to again effect wire wear. Since traction between the wire and the shell is largely dependent upon the amount of vacuum in the suction area of the primary couch, this vacuum is used to control the amount of helper drive input to the roll.

When the forming wire is driven with no stock on it, it is desirable to put some driving effort into the primary couch so that the forming wire is not called upon to start this roll. This helper driving effect should necessarily be quite small since there is little traction between the roll and the wire. However, as stock is deposited on the wire and the suction area of the roll is covered with the web of paper being formed from the stock, the vacuum in the primary couch can build up since it is no longer directly vented to the atmosphere. As a result of the increased vacuum in the suction area, more traction exists between the wire and the primary couch and more power input can be supplied to the couch without relative slippage between the couch roll shell and the wire. This is now automatically accomplished by the vacuum control of this in vention.

At the same time, in the event the forming wire is operating at a certain speed with stock being deposited on the wire and, for some reason or other, the stock supply fails so that the suction area of the primary couch is not covered with stock, the vacuum will decrease and, in so doing, the helper drive input will automatically decrease. In the absence of such a graduated vacuum control on the primary couch drive, the roll would spin relative to the wire due to the loss of traction because of the decreased vacuum.

It is, then, an object 01' this invention to provide vacuum controlled helper drives for suction rolls A further objector the invention is to provide Fourdrinier type paper making machines with paper machine with a primary suction couch roll automatically receiving the proper amount of driving input from the couch roll so that slippage or frictional drag between the wire and the primary suction couch roll is eliminated.-

Another object of the invention is to provide drives for suction rolls which are automatically controlled by the degree of vacuum in the rolls.

Other and further objects of the invention will be apparent to those skilled in the art from the following detailed description of the annexed sheets of drawings which, by way of preferred examples, illustrate three embodiments of the invention.

On the drawings:

Figure 1 is a diagrammatic side elevational view of a Fourdrinier type paper making machine equipped with a main couch roll and a primary suction couch roll which is driven with one form of helper drive from the main couch roll.

from this paper stock. will drain through the wire, and this drainage will be augmented by suction in the suction boxes I so that, by the A stationary suction box lib is mounted within invention is to I the shell l3 and has seals lfic engaging the inner surface of the shell to define therebetween a localized suction area [5d covered by the wire H and the paper web W on the wire. This suction area will extract additional amounts of liquids from the web W to feed a more dehydrated web couch roll, and the helper drive shown in Figure 1.

' Figure 3 is a plan view similar to the view of Figure 2 but illustrating a second form of helper drive for the primary suction couch roll.

Figure 4 is an enlarged plan view, with parts broken away and shown in vertical cross section to illustrate underlying parts, of an eddy current clutch used in the helper drive of Figure 3.

Figure 5 is an end-elevational view of the eddy current clutch taken along theline VV of Fig- .ure 4.

' tionary suction boxes II are mounted within the loop of the wire H for acting on the upper run of the wire. In accordance with this invention, a primary suction couch roll I5 is also mounted within the loop of the wire i I to act on the upper run of the wire after it has passed over the last suction box l4 and before it reaches the main couch roll l3.

As indicated, the wire H has the upper run thereof extending in a substantially horizontal plane from the breast roll l2 to the primarysuction'couch roll IS. The wire then slopes downwardly to the main couch roll l3 and passes around this couch roll l3 over a tensioning roller l6 and'under a guide roller I! back to the under side of the breast roll l2.

A headbox I3 is provided adjacent the breast roll l2 and has an inlet IQ for discharging paper stock onto the upper run of the wire I I. Liquids to the main suction couch roll l3. Since the shell Ilia rotates and, in accordance with this invention, is driven at speeds and with suflicient driving torque to prevent slippage between the wire'and shell, it is possible to extract higher proportions of water from the web than can be extracted by the use of stationary suction boxes since the wire must be dragged over the boxes and, if the vacuum therein is too high, the wire will be damaged by the resulting high frictional drag.

The main couch roll I3 is also preferably a suction roll including a perforated rotating shell I30; and a stationary suction gland l3b with seals |3c defining therebetween a suction area i3d over which the wire ,II and web W pass.

Since the wire II is wrapped around about half of the circumference of the main couch roll shell l3a, and since this couch roll has a suction area l3d acting on the most dehydrated portion of the web W on the wire, excellent traction will be afforded between the wire and the shell l3a. It is, therefore, highly convenient to drive the wire I I by driving the shell l3a.

As shown in Figure 2, a main drive pulley 20 driven by a belt or other prime mover 2| drives the input shaft 22 to a gear box 23 which, in turn, drives the intake shaft 24 to the shell i3a of the main couch l3. A pulley 25 is driven by the intake shaft 24 and drives a belt 26 for driving a pulley 21 on the intake shaft 28 t0 the Shell l5a 0f the or block 23b of the yoke 29a is slidably mounted.

A piston 35 is slidably mounted in the chamber 33 and has a rod 36 extending therefrom through the partition wall 32, to the block 2912 for actuating the block in accordance with movements of the piston; Packing 37 is provided in the partition wall 32 around the piston rod 36 to prevent leakage out of the chamber 33 between the piston 35 and the partition wall 32. The portion of the chamber below the piston 35 is vented to the atmosphere as at 33.

A coiled spring 39 is mounted in the chamber 33 between the bottomwall and the piston 35 to urge the piston in an upward direction, Spring pressure on the piston can be adjusted by means of a screw rod 43 threaded in the bottom wall of the casing 3i and having a seat 4| on its inner end bottoming the spring 99. This spring 39 can therefore urge the pulley 29 against the belt with the desired amount of tension so that the belt will drive the pulley 21 and shell |5,a even though no vacuum exists in the suction gland |5b.

A pipe or tube 42 connects the portion of the chamber 33 between the piston 35 and partition wall 32 with the interior of the suction gland 5": so that, as the degree of vacuum builds up in the suction gland I 51), the piston will be drawn tward the partition wall 32 and thereby effect movement of the idler pulley 29 to further tension the belt 26 and decrease slippage between the belt and pulleys 25 and 21. As a result of this control, the shell |a will receive more driving effort from the main couch roll drive as the degree of vacuum in the shell increases. As the degree of vacuum decreases the piston 35 can drop in the chamber 33. When no vacuum occurs in the suction gland l5b, the spring 39 will be the sole urging medium acting on the idler pulley 29.

As shown in Figure 2, the suction gland |3b of the main couch roll l3 can be evacuated through a vacuum pipe |3e. Likewise the suction gland |5b of the primary suction couch roll l5 can be evacuated through a vacuum pipe |5e. The pipes lite and |5e can be connected with a vacuum pump (not shown).

In the modification disclosed in Figures 1 and 2, therefore, a slip belt drive is provided between the main couch and the primary couch, and the amount of slippage between the belt and the pulleys for driving the primary couch is controlled in inverse proportion to the amount of vacuum in the suction gland of the primary couch.

It will be noted from Figure 2 that the pulley driven by the belt 25 is of smaller diameter than the ulley driving the belt 25 so that the shell |5'a will be driven at higher circumferential or linear speeds than the circumferential speeds of the shell |3a. This speed differential is necessary since the wire H is at its point of greatest tension as it comes onto the shell l5a since'it is being pulled along its upper run over the suction boxes M which impart a frictional drag thereto. As it passes beyond the shell l5a to the shell |3a. the wire is in a less stretched condition and therefore the shell I 3a should be driven at a lower circumferential speed so that it will not again stretch the wire to the condition existing as the wire comes onto the shell I5a. When driving a stretchable belt, therefore, it is not feasible to directly couple a plurality of driving rolls.

In the embodiment of Figure 3. parts identical with parts described in Figures 1 and 2 have been marked with the same reference numerals. However, in Figure 3, the belt 26 driving the pulley 21 is taut at all times so that there will be no slip between the pulleys 25 and 21. In this embodiment the intake shaft 28 to the primary suction couch roll drives an electric slip coupling 50 which controls the amount of driving effort applied to the shell l5a.

As best shown in Figures 4 and 5, the slip coupling 50 is composed of a metal armature drum 5| driven by the shaft 29 and having interior transverse slots 52 in spaced relation around the inner periphery thereof to define inwardly projecting transverse teeth 53. The armature drum 5| has a hub 5la connected to the shaft 28.

A magnetic spider 54 is mounted within the armature drum 5| and has a hub 54a connected to a shaft 28a which is coupled directly with the shell I541.

The spider 55 has a rim portion 55 with upstanding end flanges 55 providing a chamber 51 in which is wound an annular coil of wire 55. The coil is covered with a non-magnetic plate 59, and the flanges 55 are transversely grooved as at 56a to define teeth 60 around the periphery of the spider. The teeth 50 on the spider and the teeth 59 on the armature drum do not engage.

A pair of current-conducting slip rings 6| and 52 are mounted in insulated relation on the hub 54 of the spider. One end 58a of the coil 55 is connected to the ring 9|. The other end 59b of the coil 58 is connected to the ring 52.

The rings 5| and 62 rotate with the spider since they are fixedly secured on the hub thereof.

Brushes 63 and 64 contact the slip rings GI and 82 respectively. These brushes are stationary with the brush 63 connected to a wire 65 leading to a battery 69 or other source of electrical power and with the brush 64 connected to a wire 91 leading to a rheostat 58. A roller or other contactor 69 is provided in the rheostat 68. This rider 69 is fixedly mounted on a piston rod 10 having one end thereof slidable through a conductor ring H which is connected by a wire 12 back to the battery or other source of current 65. The other end of the rod 10 extends into a casing 13 and has a piston head 14 mounted on the end thereof. The piston head is slidable in the easing 13 and a spring 15 disposed around the rod 10 between the casing 13 and. the contactor- 59 urges the piston toward the top end of the casing to move the contactor toward the end of the resistance element in the rheostat so that, when the spring is acting freely, only a small amount of current will pass through the rheostat to the slip coupling.

The bottom of the casing I3 is connected through a tube or pipe 16 to the interior of the suction gland |5b in the primary suction couch roll l5. As vacuum builds up in this suction gland |5b the piston 14 will be drawn toward the bottom of the casing against the pressure of the spring 15 to decrease the amount of resistance in the circuit to the slip coupling. The casing can be vented as at 13a between the top thereof and the piston 14 so that the piston can move in accordance with the differential pressures existing on opposite sides thereof.

The electric slip coupling 50 contains no frictionally engaging couplings members and coupling efiect is obtained by energization or excitation of the coil 58 from the source of current 55 to create a magnetic field around the coil. This magnetic field induces eddy currents in the armature drum and field when there is any relative movement between them. The degree of excitation of the coil determines the amount of slippage of the parts. When the coil is deenergized the drum 5| can rotate freely around the spider without turning the spider therewith. When the coil is energized the magnetic flux will drag the spider with the drum. However, a certain amount of slippage will always occur within the coupling.

In the assembly of Figure 3 the drum 5| of the coupling will, of course, be driven by the inshaft and belt connection from the drive to the main couch roll I3 and the amount of driving effort applied from this inshaft to the shell |5a of the primary couch can be directly controlled in accordance with the amount of energization or excitation of the coil, Since the rheostat controls the amount of excitation of the coil, and since the rheostat, in turn, is itself controlled by the degree of vacuum in the suction gland l5b,

I exciter.

is automatically controlled by the vacuum.

The rheostat can be initially set so that it will permit slight excitation of the coil in the slip clutch whereby upon starting driving of the forming wire II by initiation of rotation of the main couch roll l3, the roll IE will also start to rotate However, if no vacuum exists in the roll IS, the torque input to the roll will be slight. Then, as vacuum builds up in the roll, the torque input will beincreased in proportion to the degree of vacuum by virtue of automatic movement of the piston 14 which decreases the rheostat resistance and increases the excitation of the coil in the slip coupling. Therefore, as traction between the wire and roll builds up, the helper drive effect or power input to the roll automatically increases.

In the third embodiment of the invention, as shown in Figures 6 and 7 parts identical with parts described in Figures 1' to have been marked with the same reference numeral.

As shown in Figure 6, the main couch roll I3 is driven as in Figure 2 from the gear box 23.

with the armature Ila of the motor H and the armature 15a of the booster generator 15 by means of wires I1, 18 and I9.

The field 10b of the generator 10 is connected by a wire 80 to a vacuum-operated rheostat 8| 'havinga piston-operated contactor or bridge 82 establishing contact to awire 83 connected with the field 1 lb of the motor H.

The contactor 82 is secured to a piston rod 84 extending into a casing as. A piston as is slidable in' the casing and is secured to the bottom end of the rod 84. The casing is vented as at 81 above the piston and the bottom of the casing is connected through a tube or pipe 88 to the suction gland l5b of the primary couch roll IS, A spring 8-9 surrounds the rod 84 and is compressed between a stop 84a on the rod and the casing 85 to urge the contactor 82 to a position for, increasing the resistance efifect of the rheostat in the field circuit.

A wire 38 connects the other end of the field coil Nb of the motor II to the field coil b of the generator 15 and a wire 98a is tapped from the wire 90 back to the field coil 1%. As shown in Figure '7, a variable resistance element 92 can be incorporated in circuit between the field coils lib, 18b, and 15b. v

The armature 16a of the exciter 16 has one end connected through. a, wire 8| to the wire 80 while the other end is connected through a wire 93 to the wire 83 and field coil 1517. A variable resistance element 94 can be included in the circuit to the field coil 15b. The field coil 16b of the exciter I8 is in shunt circuit with the armature 18a and avanable resistance element 95 can be included in this circuit.

Thus the field coils 10b, Ilb, and bare in series arrangement with the armature of the The generator ID will generate current to drive primary couch. However, the amount of current supplied to the motor II by the generator 10' will depend upon the amount of vacuum in the suction gland Iiib. As the vacuum builds up in this gland the piston 86 will be drawn down to de crease the rheostat resistance in the'clrcuit to the generator field and thereby increase power input to the motor.

The small booster generator I! is used to circulate current through the generator Ill and the ll over the primary couch when the wire is first started up.

The small exciter 16 is used to excite thev fields of the booster generator 15, the main generator 10, and the motor II, The degree of. excitation can be controlled through the resistance elements 92, 94 and 95. The exciter I6 is a small directcurrent exciter.

Therefore in the third embodiment of the invention the primary couch driving motor 1| always has a small amount of torque applied thereto through the constantly running motor 13. This small amount of torque, however, is not suflicient to turn the shell lSa. Nevertheless, as soon as the main generator 10 starts to function by driving the main couch roll l3 there will be sufficient torque available to immediately start the shell l5a. After the shell l5a starts rotating the torque or power input thereto is automatically controlled in accordance with the amount" of vacuum existing in the suction gland l5b. Thus, as traction between the'wire II and the shell l5a builds up due to increased vacuum in the roll, the helper drive efiect or power input to the shell automatically increases.

It should :be understood that more than one primary suction couch roll assembly can be used in the loop of the forming wire. and that the helper drives of this invention can be used in driving a plurality 'of suction rolls from a single main couch roll. I r

In all illustrated embodiments of the invention the helper drive is driven at speeds slightly greater than the direct drive speed to the main couchQ In all illustrated embodiments of the invention the degree of vacuum in the primary couch automatically controls the power input to the primary couch.

It will, of course, be understood that various details of the invention may be varied through a wide range without departing from the principles of this invention and it is, therefore, not

the purpose to limitthe patent granted hereon otherwise than necessitated by the scope of the appended claims.

We claim as our invention:

1. In a Fourdrinier type. paper making machine including a looped forming wire, a main couch roll within the loop of said wire, a primary suction couch roll within the loop of said wire for acting on stock deposited on the wire in advance of the main couch roll, means for driving said main couch roll to drive the wire, a helper drive the motor 1| for rotating the shell I541 0f the between said means and said primary suction couch roll, and pressure responsive control means controlled by the degree of vacuum in the primary driving eilect of said helper drive so as to correlate the amount of drive on said primary suction couch roll with the traction between said primary suction couch roll and the wire.-

2. In a Fourdrinier type paper making machine including a looped forming wire, a main couch roll within the loop of said wire, a primary suction couch roll within the loop of said wire, means drivirfg said main couch roll to drive the wire. a slip device driven by said means to drive the primary-couch roll, and means including piston operated means movable in response to changes in pressure and controlled by the degree of vacuum in the primary couch roll for varying the drive eflect of said slip device on said primary couch roll.

3. In a Fourdrinier type paper making machine, a looped forming wire, a main couch roll within the loop of said wire, a primary suction couch roll within the loop of said wire, said rolls being in engagement with said wire, an inshaft driving said main couch roll to drive the wire, an inshaft to said primary couch roll to drive the same, a slip connection between said inshafts, and means including a piston operated device movable in response to changes in pressure and controlled by the degree of vacuum in the primary couch roll for controlling the amount of slippage in said slip connection.

- 4. In a couch roll driven forming 'wire assembly oi! a paper making machine, a primary suction couch roll engaging the forming wire in advance of the wire driving, couch roll, inshai'ts for driving the shells of said rolls, pulleys on said inshafts, a slip belt connecting said pulleys in driving relation, an idler pulley acting on said belt to control the amount of slippage thereof, and means actuated by the degree of vacuum in said primary couch roll for actuating the idler pulley to tighten the belt as th degree of vacuum builds up in the primary couch roll.

5. In a couch roll driven forming wire assembly of a paper making machine, a primary suction couch roll within the loop of the forming wire in engagement therewith in advance of the wire driving couch roll, inshatts to both 01' said rolls, a driving connection between said inshafts, an electric slip coupling between said driving connection and said primary suction couch roll, and means including pressure control means controlled by the degree of vacuum in said primary suction couch roll regulating th electrical energization of said coupling for controlling the degree of slippage of said slip clutch so as to minimize slippage between said primary suction couch roll and forming wire.

6. In a paper making machine, a plurality of rolls including a suction roll for moving a band, means connecting said rolls for co-rotation, an electric slip clutch between said means and said suction couch roll for automatically varying the suction roll for controlling the amount of drive from said suction roll to the band, a coil in said clutch, means for energizing said coil to control the amount or slippage therein, rheostat means to vary the energization of said coil, and a vacuum operated device controlled by the degree oi to drive the same, and a vacuum operated rheostat actuated by the degree of vacuum in said suction roll in circuit arrangement with the field of the generator and the field of the motor to supply more driving torque to the motor as the degree of vacuum in the suction roll increases.

8. In a paper making machine, a pair of rolls including a suction roll, a motor for driving said suction roll, means for driving the other of said rolls, a generator driven by said means, the armature of said generator being connected in series with the armature of said motor, a booster generator having the armature thereof in series with the armature of said motor, a driving motor for said booster generator, a direct current exciter driven by said driving motor, a circuit connecting the fields of the generator and the motor, a vacuum operated rheostat in said circuit controlled by the degree of vacuum in said suction roll to increase the field strength in the generator as the vacuum in the suction roll increases, said booster generator circulating current through said generator to supply a small amount of torque to the motor for initiating rotation of the suction roll immediately upon initiation of rotation oi said other roll.

9. In a Fourdrinier type paper making machine including a looped forming wire, a breast roll within the loop of said wire, a couch roll within the loop of said wire and spaced from the breast roll to cooperate therewith for training the wire to provide an upper forming run, said couch roll being arranged for driving the wire, a primary suction couch roll within the loop of said wire engaging the upper forming run of the wire in advance of the couch roll, means for driving said couch roll, and a helper drive from said means for driving the primary suction couch roll at higher circumferential speeds than the couch roll to accommodate stretch of the upper forming run of the wire between thebreast roll and primary suction couch roll as well as shrinkage of said run of the wire between said primary suction couch roll and said couch roll.

10. In a paper making machine having a looped forming wire, a suction roll within the loop of the wire in driving engagement with the wire, driving means for rotating said suction roll to move the wire, and means for controlling the drive input of said suction roll from said driving means in ac- LLOYD HORNBOSTEL EDWARD D. BEACHLER.

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