US3176651A

US3176651A - Puddle coater

Info

Publication number: US3176651A
Application number: US161670A
Authority: US
Inventors: Irvin J Phillips
Original assignee: Beloit Iron Works Inc
Current assignee: Beloit Iron Works Inc
Priority date: 1961-12-22
Filing date: 1961-12-22
Publication date: 1965-04-06
Anticipated expiration: 1982-04-06

Description

l. J. PHILLIPS PUDDLE COATER April e, 1965 7 Sheets-Sheet 1 Filed DEG. 22, 1961 INVENTR.

I. J. PHILLIPS April s, 1965 PUDDLE COATER 7 Sheets-Sheet 2 Filed Dec. 22, 1961 INVENTOR. [1w/72 ff 5"//275 BY h.; fr

f ATTORNEYS l. J. PHILLIPS PUDDLE COATER April 6, .1965

7 Sheets-Sheet 3 Filed Dec. 22. 1961 JHM/ 2 2,

IU, J. NU w @L l. J. PHILLIPS PUDDLE COATER April s, 1965 7 Sheets-Sheet 4 Filed Dec. 22. 1961 INVENTOR. f77/72 JPztf/'as BY 2 5 w/ l. J. PHILLIPS PUDDLE COATER April e, 196s 7 Sheets-Sheet 5 Filed Dec. 22, 1961 INVENTOR. ffvz'?? JP//v BY A, KQTTORNEYS l. J. PHILLIPS PUDDLE COATER April 6, 1965 7 Sheets-Sheet 6 Filed DeO. 22. 1961 w 3 nl. 4

BY ATTORNEYS April 5, 1965 1. J. PHILLIPS 3,176,651

PUDDLE COATER Filed Dec. 22, 1961 '7 Sheets-Sheet 7 INVENTOR.

UnitedStates Patent O 3,176,651 PUDDLE CUATER Irvin J. Phillips, South Beloit, lill., assigner to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Filed Dec. 22, 1961, Ser. No. 161,670

9 Claims. (Cl. 11S-413) Y The present invention relates to improvements in paper machines and particularly to an improved mechanism for applying a coating to the surface of a travelling web using a coating doctor blade with a puddle of coating liquid carried between the blade and web.

In puddle coaters of this type a travelling web passes over the surface of a rotating backup roll and a trailing doctor blade is applied to the web surface, and a supply of coating is provided to the upper surface of the blade to maintain a pool or puddle of coating between the blade surface and the surface of the travelling web. The blade is either loaded against the web with a predetermined pressure or in some instances circumstances require gap operation with a predetermined very small space between the blade edge and the paper surface. The thickness of the layer of coating applied to the web surface is a function of the blade loading pressure and the blade angle. It is therefore important to be able to apply a uniform pressure and an accurately controlled pressure to the blade. It is also important to achieve this objective while providing a mechanism which can readily handle the doctor blade and move it away from the backup roll for changing blades and for rethreading a web after web breakage. It is also important to obtain a neat appearance and ease of operation and maintenance and to accommodate versatility in coating which requires ybeing able to change blade angles and vary coating weights.

An object of the present invention is to provide an improved puddle coated which has mechanism permitting adjustment to compensate for doctor blade Wear and has mechanism which enables more accurate and reliable adjustment of the operating pressure between the doctor blade and the surface of the travelling paper web.

A further object of the invention is to provide an improved blade pressure control mechanism for a puddle coater wherein the blade pressure can be accurately controlled or the blade can be operated with a gap between its coating edge and the surface of the travelling web.

A still further object of the invention is to provide an improved arrangement for the puddle type coater for performing the function of simply and rapidly moving the doctor blade toward or away lfrom the surface of the moving web, for supporting the weight of the operating mechanism, and for controlling the pressure between the 'blade and the travelling web surface.

A still further object of the invention is to provide an improved wiper blade mechanism for handling excess coating material when the coating doctor blade is moved away from the backup roll, such as when a web break occurs.

A still further object of the invention is to provide a mechanism having the sole function of controlling the loading pressure between the doctor blade and travelling paper web and wherein the mechanism has an operative range of travel which is maintained the same with variations in operating circumstances, to obtain more accurate control of blade loading pressure.

A still further object of the invention is to provide a puddle coating mechanism which accommodates change in blade angle.

A further object of the invention is to provide a coating mechanism employing a wiper doctor blade of improved construction for engaging the paper sur-face when 3,176,651 Patented Apr. 6, 1965 the coating doctor is dropped away from the ,surface and embodying mechanism for catching coating from the Wiper doctor and running downwardly from the coating doctor.

Other objects, advantages and features will become more apparent with the teaching of the principlesvof the invention in connection with the disclosure of the preferred embodiment thereof in the specification, claims and drawings, in which:

FIGURE 1 is a front elevational view of a portion of a coating machine, with parts shown in somewhat schematic form, constructed in accordance with the principles of the present invention;

FIGURE 2 is a side elevational View taken from the left side of the mechanism as shown in FIGURE l;

FIGURE 3 is a schematic top plan View showing the general arrangement of the mechanism;

FIGURE 4 is a fragmentary side elevational view of a portion of the mechanism of FIGURE 1 showing details thereof;

FIGURE 5 is a sectional view taken substantially along line V-V of FIGURE 4;

ice

FIGURE 6 is a fragmentary detailed top plan view showing a stop mechanism;

FIGURE 7 is a fragmentary side elevational view showing the stop mechanism;

FIGURE 8 is an end elevational view taken from the front of the machine showing the wiper doctor;

FIGURE 9 is a fragmentary side elevational view taken from the right side of the mechanism of FIG- URE 8;

FIGURE 10 is a sectional view taken substantially along line XX of FIGURE 2; and

FIGURE ll is a sectional view taken substantially along line XI-Xl of FIGURE 9.

As shown on the drawings:

FIGURES l and 2 show the front end of a portion of a paper machine employing a coater embodying the principles of the present invention, and the coater is designed with standard front `and rear mechanism suitable for a range of sheets Widths, with the mechanism being substantially identical on both ends of the machine yso that only one end may be described in detail. FIGURE 3 is a plan View of the machine shown in schematic with a backup roll 1G rotataby supported on bearings 10a and 10bat theends and a doot-or back assembly 12 for supporting a doctoi blade, mounted in pivotal bearings 18a and 181).` The center line of the backup roll is shown at CL and the center line for the pivotal supports for the doctor back,

is shown at CL. A feature of the present invention permits shifting of the position of the bearings 18a and 1gb which support the doctor back 12 relative to the axis CL of the backup roll.

Y As shown in FIGURE 1, a paper web W runs over the `support surface of the cylindrical backup roll 10 and coating is smoothed on the outer surface of the web W by a coating doctor blade 11. The coating blade 11 is supported on a doctor back shown generally at 12 for rigidly supporting the blade 11 and is supporte-d on arms 18C in the end bearings 13a and 1817 on upright bearing support posts 1S which are supported on the frame F, and which `are adjustable 'as will be described.

The doctor back land doctor blade can be swung downwardly toa rest position as shown by the dotted line position of I(the blade 11 in FIGURE 1, by operation of a first blade support and moving member provided in Ithe form of ya cylinder 13 with a piston slidable therein connected rto a piston rod 14 which is connected to the doctor back 12 lat a pivot point 14a. The piston has a relatively long range of movement and strikes stops Within the cylinder for moving the doctor blade between the rest position shown in dotted lines in FIGURE 1 and a ready position mechanism, `and applies a force to the arm to bring the blade into close .relation with the surface of the web W with zero pressure. A third blade support member in the form of air spring 17 operates solely to apply a loading force or in other words to control the pressure between the coating blade 11 and the surface of the web W, to thereby place the blade into close running relation with the web. The close running relation or blade pressure may also be controlled, in an alternate method of operatingthe equipment, by a micrometer stop as will be later described.

In greater detail, the doctor blade 11 is' held on the doctor back 12 by a clamping [arm 19 which is pressed against the blade by a toggle linkage 20 that snaps outwardly to release the blade for blade replacement. The toggle linkage 29 is shownin a blade holding position, being held in that position by an adjustable stud 21 which bears against the lower link of the toggle linkage 20 to maintain it in pressure position forV clamping the blade 11. The togglelinkage is supported bythe lower element being pivoted at 26a `on the arm 18C.

The upper.side of the doctor back 12 meets the lower edge of end dams 22 which have a gasket 23 along their lower edge to contain the puddle of coating liquid between the end dams and above the coating blade 11. The end dam on the end of the machine shown in FIGURE 1 is pivotally supported and can be swung out about a vertical axis on mechanism which need not be described in detail. The mechanism holds the end dam in place and it remains rigid while lthe doctor back 12 swings downwardly to the dotted line position of FIGURE Land does not follow the doctor back.

The bearing column or post 18 for the bearing 18a which supports the doctor back is horizontally slidable on a track surface 24 on the frame F. As shown in FIG- URES 4 and 5, an adjustment bolt 25 is rotatably mounted at its head end in the column and is threaded into an upstanding lug 26 on the frame F so that rotation of the bolt will slide the bearing column 18 toward or away from.

the center of the backup roll 10. Cap screws 27 extending down through slotted openings 28 lock the bearing column 18 in its adjusted position. The bearing column at each end of the doctor blade is adjusted for the proper blade angle and for uniform blade contact across the machine. As will be observed, the angle of the blade with respect to the paper web will be changed by moving the columns closer to the backup roll 10 or by moving them further away therefrom. For example, as the columns are moved closer to the machine the blade 11 will have to be droppeddown so that it will then engage the outer surface of the paper web W at a more flat angle, and as the columns are moved back away vfrom the backup roll the blade will be raised upwardly to increase its angle with respect to the surface of the web for a stiler blade action. The end darn 22 will of course have to be changed to accommodate the angle of the blade.

When the proper blade angle is chosen by adjustment of the bolts 25 which are accessible by removal of the end caps 25a, a spaced block 29 is positioned between the surfaces and 31 of the bearing column 18 and the frame F. Since the position of the backup roll 10 remains unchanged at all times, this spacer block can be accurately machined and can be reused in order to obtain the same conditions at some other times, and diiferent sets of spacer blocks can be employed for different operating conditions. The spacer blocks are held in place by studs 29a.

The operation of the air springs 16 and 17 is most effective through a predetermined range of extension, and most accurate through that range of operation, and by setting adjustable connector 33 between the arm 15 and the cylinder 13, the air springs will always operate through said predetermined range.

The adjustable connection 33 can also be changed t0 compensate for doctor blade wear and wear in the backing roll 10. This avoidsusing the air springs 10 and 17 to take up wear. As the air springs expand further the ette-:tive area drops rapidly resulting in higher air pressure requirement and adjustment, and this is avoided by use of the adjustable connection 33.

The connection 33 employes an upper portion 34 having a pivotal pin 35 for supporting the cylinder 13. The ufnfr portion 34 has grooves or tracks receiving mating tra :s on a lower portion 38 on the arm 15. An adjustment bolt 36 is rotatably supported in a downwardly depending lug 39 on the upper portion 34 and is threaded into the portion 3S on the arm 15 so that with rotation of the bolt 36 the connection 33 is slidably adjusted.

The air cylinder 13 is provided `with a suitable air connection, not shown for reciprocating the piston therein, air at controlled pressures is supplied from a suitable source to the air springs 16 and 17 through connections and 41. The air springs are in the form of annular closed bellows having flexible walls secured at one end tothe arm 15, and at the other end to a bracket on the frame F.

A stop bolt 42 limits the pivotal movement of the arm 15 when the airsprings 16 and 17 are collapsed, to prevent damage thereto. The pressure in the air spring 17 will determine the coating blade pressure.. However if pressure in the air spring 17 uctuates for Some reason, the blade pressure will also liuctuate. This may be avoided by a second method of operation utilizing the positive stop 43.

The stop 43 incorporates a stop bracket 45 mounted on the bearing colum 16. The bracket has a stop surface 44 which is arcuate and is swung about the intersection point of extension lines of the blade angles at the maximum and minimum blade angle setting.

Attached to the doctor back 12 is a micrometer 46 rotatably supported in a bracket 48 on the doctor back. A manual adjustment screw 47 is attached to the micrometer. 46.

in operation, the piston in cylinder 13 extends to the end of its stroke to bring the blade 11 into ready position, and the air spring 16 is pressurized to bring the blade up into close running position against the web W at zero pounds blade pressure. which has been retracted, is screwed into contact with the surface 44 of the stop 45. The blade pressure remains at zero. The pressure between themicrometer and the stop will also be zero. The lower diaphragm of air spring 17 is then inflated to a pressure preferably at the maximum pressure allowable therein. The pressure between the micrometer and the stop increases but the blade pressure remains at zero. By retracting the micrometer turning the knob 47, the blade will be allowed to gradually contact the web with increasing pressure. Coating will have-been supplied in a puddle abovev the blade, and the micrometer is adjusted until the desired coating weight is obtained. The coating layer applied (and the blade pressure) is now a function of the position of the micrometer rather than a function of the pressure of the lower air spring 17. Fluctuation of pressure in the lower air spring 17 will no longer iniiuence the blade pressure and the amount of coating applied.

ln some coating operations it is required to maintain a gap between the blade and the web surface while coating. The amount of coating applied is then a function of the size of the gap. This gap operation isV achieved by inflating the cylinder 13 .and the air spring diaphragm 16 as above described, and also inflating the The micrometer 46,`

air spring or diaphragm 17, and instead Vof turning the micrometer to permit the blade to move toward the backup roll lt), the micrometer is turned in an opposite direction extending the micrometer and forcing the doctor back and blade toward the left, as shown in FIGURE l, until the desired gap is obtained.

With the micrometer set, the blade pressure is fixed and will not vary. The blade can be moved away from the backing roll, such as might be necessary with a web break as shown in the dotted line position of the micrometer 45 of FIGURE 7, and returned against the web as shown in the solid line position of the micrometer de, whereupon the blade will maintain the same pressure. With wear of the blade, or installation of a new blade, the connection 33 can be adjusted which of course will require resetting the micrometer 46.

FIGURES 8, 9, and ll show a wiper doctor arrangement having a wiper doctor blade 51 which is brought into Contact with the surface of the web W on the backup roll if@ when the coating doctor 11 is dropped downwardly, such as when a web break occurs. This may be automatically accomplished by a web break detector which releases the =pressure in the cylinder 13 and in the diaphragms 16 and i7 and simultaneously pressurizes cylinder 56. Cylinder 56 has a piston therein connected to a piston rod 5S which is connected to an arm 55 to operate the wiper doctor 51. The wiper doctor is mounted on a doctor back 53 pivotally supported at 54 and movable between a rest position as shown at FIGURE 8, and a doctoring position in engagement with the web on the backup roll 10.

The wiper doctor 5l is normally in the rest position and is brought up against the web only when the doctor 11 is dropped, and then functions to wipe excess coating from the paper web and prevent a gob of coating from passing through the machine beyond the backup roll.

A saveall pan 59 catches coating which iiows downwardly from the wiper doctor 51 and catches coating which is dripped downwardly from the idoctor blade il, and for this purpose must be moved from the right-hand position shown in dotted line form in FIGURE 8 to the left-hand position. With the arrangement of the present invention, the same operating mechanism which brings the wiper doctor into operation also positions the saveall pan.

The doctor back 53 has an upwardly extending arm 63, and a link 64 connects between the arm 63 and a rigid arm 62 on the saveall pan. The pan is pivotally mounted at e@ and as will be observed it pivots to the left in FIGURE. 8 with extension of the piston rod $8 and movement of the Wiper doctor 5l to web engaging position. A stop bolt 65 engages a stop 6o to limit the position and the contact pressure of the wiper doctor 5l. The saveall pan is provided with a drain 61. The elements are suitably supported on their frame F, and the cylinder 56 is supported on a bracket 57 thereon.

rihus it will be seen that I have provided an improved coating mechanism for coating a travellin-g paper web which meets fthe objectives and advantages above set forth. The mechanism is rugged and reliable in operation, and is well suited for continuous and suitable operation in the atmosphere of moisture and foreign elements which are present near a papermaking machine or near a coating machine. The assembly provides a neat appearance, ease of operation and maintenance, versatility in types of coating (capability of change of blade angles with varying coating weights) and the blade loading arrangement with the diaphragms and arms are enclosed and protected. The apparatus also provides for simpliiied backing roll removal in that the coating doctor is not disturbed when the backing roll is removed.

It will be appreciated that the mechanism can be operated by three separate methods. In a irst method the blade pressure is controlled by the lower diaphragm t7.

In the second method, the blade pressure is controlled by the adjustment of the micrometer. In the third method no blade pressure is employed and gap operation is utilized.

The drawings and specilication present a detailed disclosure of the preferred embodiments of the invention, and it is to be understood that the invention isnoft limited to the specific forms disclosed, but covers all modiications, changes and alternative constructions and methods falling within the scope of the principles taught by the invention.

I claim as my invention:

1. A mechanism for coating a travelling paper web comprising a backup roll for supporting the travelling web, means for supporting a doctor blade for Vengagement with the web on the roll, a rst blade support member connected to said support means for moving the blade from a rest position away from the backup roll to a ready position, a second blade support member connected to said first support member for moving` the blade to a close position relative to the roll and supporting the Weight of the blade in that position, and a third blade support member also connected to said rst support member for controlling the blade pressure in a close running position, means connecting said second and third members to said rst member to accommodate the second and third members in acting on the doctor Iback, and means for adjusting said connecting means so that sai-d second and third members will act on the blade in a predetermined range of movement.

2. A coating mechanism for coating a travelling paper web comprising a backup roll for supporting the travelling web, a doctor back for carrying a doctor blade to be engaged with the surface of the web, a iirst blade support member for moving the blade from a rest position away from the backup roll to a ready position, a second blade support member connected to said rst member and supporting the weight of the first member and of the blade and back in a close position relative to the backup roll, a third blade suppont member connected to said first member and controlling the blade pressure in a close running position, and connecting means between said first support member and said second and third members being adjustable so that said second and third members will operate through a predetermined range of movement.

3. A coating mechanism for coating a travelling paper web comprising a doctor blade to be moved against the surface of the travelling web, a backup roll for supporting the web, a tirst blade positioning means for moving the blade through a fixed distance from a rest position to a ready position, second blade positioning means for moving .the blade to a close running position, a pivotal mount for said blade connected to said rst blade positioning means, means for adjusting the position of said pivotal mount relative to the axis of the backup roll for changing the blade angle, and an adjustable length connection between said first and second positioning means whereby said second means acts on the blade through said lirst means and in a predetermined range of movement.

4. A coating mechanism for coating a travelling paper web comprising a backup roll `for supporting the travelling web, a pivotally mounted support for supporting a doctor blade to be moved lagainst the Web on the roll, a blade support piston and cylinder unit connected to said support for moving the blade from a rest posi-tion away from the backup roll -to a ready position, a pivotal .arm connected to the blade support piston and cylinder unit, rst and second expansible Huid actuated members acting on said farm, said rst member supporting the weight of the piston and cylinder unit and blade, said second member controlling the close running position of the blade, means for adjusting the position of the pivotal mount vfor changing the blade angle relative to the surface of the moving paper web, and an adjustable connection between said arm and said piston and cylinder 8 unit so that the tiret and second members may act through a predetermined range of movement with change in position ofsaid pivotal mount.

5. A coating mechanism for coating .a travelling paper Web comprising a backup roll for supporting the travelling web, a doctor blade for engaging the web in a coat ing operation, means for moving the doctor blade between a close running position and a rest position away from the web, a wiper blade at a location following the doctor blade and adapted to be moved against the roll with breakage of the web and movement of the doctor blade to rest position, a saveall pan for catching liquid coating from the doctor blade as it is moved to rest position and for catching coating from the wiper blade in an operating position, and means for simultaneously moving said wiper blade to operating position against the roll and moving said saveall pan from a rest position to operating position.

6. A coating mechanism for coating a travelling paper web comprising a doctor back for supporting a doctor blade against the web, a backup roll for supporting the travelling web, means for moving the doctor blade be- .tween a close running position and a rest position away from the web, a wiper blade to be moved against the roll with movement of the doctor blade to rest position, a saveall pan for catching liquid coating from the doctor 4blade as it is moved fto rest position and for catching coating from the wiper blade in close running position, an expansible uid chamber for moving the wiper blade to close running position and for moving the saveall pan to operating position, yand means interconnecting said pan and wiper blade for operation by said iluid chamber.

7. In a coating mechanism for coating a travelling paper web comprising a backup roll for supporting the travelling web, a doctor back for supporting a doctor blade against the web on the roll, a pivotal mount for the doctor back, means for urging the doctor back and blade against the roll, a stop member on the doctor back for limiting movement of the doctor blade against the web, and a stop engageable by the stop member and having an arcuate surface with its radial center at the intersection of lines providing extensions of the doctor blade in its positions at maximum and minimum blade angle.

8. A coating mechanism for coating a travelling paper web comprising means for carrying a doctor blade to be engaged with a travelling paper web, a backup roll for supporting the web, a rst blade positioning means movable toward or away from the backup roll for moving the blade through a Xcd distance from a rest position to a ready position, a pivotal arm supporting said iirst positioning means, second blade positioning means connected to the pivotal arm for moving the blade to a close running position, and an adjustable support for said rst positioning means mounted on said pivotal arm and movable on said arm toward or away from the backup roll for changing the position of said first positioning means on the arm whereby said second means acts on the blade through said rst means in a range of movement and the location lof the blade in said range is determined by said adjustable support.

9. A coating mechanism for coating a travelling paper web comprising means carrying a doctor blade to be engaged with a travelling paper web, a backup roll for supporting the web, a first blade positioning means connected to the carrying means and movable toward or away from the backup roll for moving the blade through a xed distance from a rest position to a ready position, a pivotal arm for supporting said rst positioning means, second blade positioning means connected to the pivotal arm for moving the blade from said ready position to a close running position, and a lineally adjustable slide extending in a direction substantially radially `of the backup roll and supporting said iirst blade positioning means and mounted on said pivotal arm and being adjustable for changing the position of the irst positioning means on the arm whereby said second means acts on the blade through said rst means in a range of'movement determined by the location of said slide.

References Cited by the Examiner UNITED STATES PATENTS 2,470,400 5 49 Hornbostel 15-25 6.51 3,030,917 4/62 Brown et al. 1l8-413 3,070,066 12/62 Faeber 11S- 413 3,079,889 3/63 .laCObS et al. 118-421 RICHARD D. NEVIUS, Primary Examiner.

JOSEPH B. SPENCER, Examiner.

Claims

1. A MECHANISM FOR COATING A TRAVELLING PAPER WEB COMPRISING A BACKUP ROLL FOR SUPPORTING THE TRAVELLING WEB, MEANS FOR SUPPORTING A DOCTOR BLADE FOR ENGAGEMENT WITH THE WEB ON THE ROLL, A FIRST BLADE SUPPORT MEMBER CONNECTED TO SAID SUPPORT MEANS FOR MOVING THE BLADE FROM A REST POSITION AWAY FROM THE BACKUP ROLL TO A READY POSITION, A SECOND BLADE SUPPORT MEMBER CONNECTED TO SAID FIRST SUPPORT MEMBER FOR MOVING THE BLADE TO A CLOSE POSITION RELATIVE TO THE ROLL AND SUPPORTING THE WEIGHT OF THE BLADE IN THAT POSITION, AND A THIRD BLADE SUPPORT MEMBER ALSO CONNECTED TO SAID FIRST SUPPORT MEMBER FOR CONTROLLING THE BLADE PRESSURE IN A CLOSE RUNNING POSITION, MEANS CONNECTING SAID SECOND AND THIRD MEMBERS TO SAID FIRST MEMBER TO ACCOMMODATE THE SECOND AND THIRD MEMBERS IN ACTING ON THE DOCTOR BACK, AND MEANS FOR ADJUSTING SAID CONNECTING MEANS SO THAT SAID SECOND AND THIRD MEMBERS WILL ACT ON THE BLADE IN A PREDETERMINED RANGE OF MOVEMENT.