US3074476A

US3074476A - Paper machinery

Info

Publication number: US3074476A
Application number: US746450A
Authority: US
Inventors: Wesley S Corbin; Lawrence A Moore; Charles M Pearson
Original assignee: Black Clawson Co
Current assignee: Black Clawson Co
Priority date: 1958-07-03
Filing date: 1958-07-03
Publication date: 1963-01-22
Anticipated expiration: 1980-01-22
Also published as: GB927934A

Description

Jan. 22, 1963 w. s. CORBIN ET AL 3,074,475

PAPER MACHINERY Filed July 3, 1958 6 Sheets-Sheet 1 FlG-1 IN VEN TORS WESLEY S. CORBIN, BY LAWRENCE A.MOORE 8 CHARLES M. PEARSON ATTORNEYS Jan. 22, 1963 w. s. CORBIN ET AL 3,074,476

PAPER MACHINERY Filed July 3, 1958 6 Sheets-Sheet 2 Fl G3 FIG-4 w u o A/ WV W l W 6 6 h. 6 l 6 .5. m HOW? m 6 6 9 4 6 a N s R "w Mm 7 mNO% N ////r NOA. w 7/Mr/ 0W A 6 CS 6 3m aw? E H #WMC Y B Jan. 22, 1963 w. s. CORBIN ET AL 3,074,476

PAPER MACHINERY Filed July 5, 1958 6 Sheets-Sheet 3 FIG-9 l r50 I l l 1 l l 9 INVENTORS WESLEY 8. CORBIN LAWRENCE A. MOORE a BY CHARLES M. PEARSON M M aflgg ATTORNEYS Jan. 22, 1963 w. s. CORBIN ET AL 3,074,476

PAPER MACHINERY Filed July 5, 1958 e Sheets-Sheet 4 FIG-H FIG-15 I76 zz I35 H 125 Q FIG-14 IN VEN TORS WESLEY S.CORBIN LAWRENCE A. MOO'RE a BY CHARLES M. PEARSON wwm ATTORNEYS 7 L L I 302, 300 I76 Jan. 22, 1963 W. S. CORBIN ET AL PAPER MACHINERY Filed July 5, 1958 6 Sheets-Sheet 5 IN VEN TORS WESLEY S. CORBIN BY LAWRENCE A. MOORE a CHARLES M. PEARSON ATTORN EYS Jan. 22, 1963 w. s. CORBIN ET AL 3,074,476

PAPER MACHINERY 6 Sheets-Sheet 6 Filed July 3, 1958 INVENTORS WESLEY s. CORBIN, LAWRENCE A.MOORE a BY CHARLES M. PEARSON ATTORNEYS ire ttes atent Ofitice 3,074,476 Patented Jan. 22, 1963 3,074,476 PAPER MACHINERY Wesley Corbin, Lawrence A. Moore, and Charles M.

Pearson, Watertown, N.Y., assignors to The Black- Clawson Company, Hamilton, Ohio, a corporation of Uhio Fiied July 3, 1958, Ser. No. 745,454 6 Eiairns. (Cl. 162-642) This invention relates to paper making machines and more particularly to a head box for a Fourdrinier paper machine.

This invention is directed to the provision of a head box adapted for use in combination with a Fourdrinier paper machine capable of operating over a range of wire speeds which includes very high speeds requiring a high spouting velocity of the stock and correspondingly high pressure efiective on the stock within the head box for a paper machine of very large size, i.e. Width, which requires a correspondingly high volumetric flow rate of the stock, and which also presents structural and operational difiicuities from the standpoint of the stresses and pressures involved in maintaining uniform conditions over a wide area at high pressure and flow rates. For example, the invention has been developed to provide a head box capable of use with a forming Wire 300 inches in Width operating at a speed of 3000 feet per minute and requiring a stock flow at the rate of 40,000 gallons per minute at pressures of the order of 38 feet of water. The invention also contemplates that the same head box will operate with equal efficiency at comparatively low wire speeds requiring an effective head of only a few inches of water.

It is a primary object of the present invention to provide a head box having the characteristics and operating range outlined in the preceding paragraph, and particularly to provide such a head box which will produce a sheet of high and uniform quality over its entire range of operating speeds.

Another object of the invention is to provide a head box as outlined above which incorporates a plurality of rectifier rolls arranged in such spaced and over-lapping relation as to cause the maximum proportion of stock to transverse two or more rectifier rolls before reaching the outlet onto the wire, and particularly to prevent the possibility of the stock passing directly through the flow chamber within the head box without being subjected to rectifying action.

An additional object of the invention is to provide such a head box in which each of a plurality of rectifier rolls is mounted for individual adjustment both horizontally and vertically with respect to each other with minimum possibility of leakage from the interior of the head box, and particularly wherein the rolls adjacent the mov able upper slice lip are adjustable into maintained relationship with the slice lip and with each other to assume eifective rectifying action in all positions of adjustment of the slice lip.

A further object of the invention is to provide a head box capable of the high operating speeds outlined above which incorporates an inlet supply passage of novel construction for assuring uniform cross flow dimensions of the approach flow of stock into the head box even with a forming wire of the very great Width and speeds indicated above.

A still further object of the invention is to provide a novel mechanism for sealing against leakage of the stock between the relatively movable parts of a head box of the general characteristics outlined above, and particularly to provide effective sealing between the side and bottom walls of the box in the portions adjacent the 2 apron cloth while assuring maximum freedom from obstructions to smooth stock flow through the box.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

in the drawings- FIG. 1 is a somewhat diagrammatic view partly in side elevation and partly broken away which shows a head box constructed in accordance with the invention;

FIG. 2 is a greatly enlarged fragment ofFIG. 1 illustrating the sealing mechanism between the top wallof the head box and the adjustable front wall which carries the upper slice lip;

FIG. 3 is a fragmentary section taken as indicated by the line 33 of FIG. 4 and illustrating the adjustable mounting for one end of one of the rectifying rolls in FIG. 1;

FIG. 4 is a view taken as indicated by the line 4-4 of FIG. 3;

FIG. 5 is an enlarged fragmentary vertical section taken as indicated by the line 55 of FIG. 6 and showing the throat structure in the inlet slice passage of FIG. 1;

FIG. 6 is a fragmentary section taken as indicated by the line 6-6 of FIG. 5;

FIG. 7 is a detail view partly in elevation and partly broken away showing one of the fin or spacer members of FIGS. 5 and 6;

FIG. 8 is a section on the line 8-8 of FIG. 7;

FIG. 9 is an enlarged fragmentary view taken generally as indicated by the line 9-9 of FIG. 10 and illustrating the connection between the lower slice lip and the side wall together with its associated sealing mechamsm;

FIG. 10 is a front elevational view looking from left to right in FIG. 9;

FIG. 11 is a fragmentary sectional view taken as indicated by the line 1111 of FIG. 9;

FIG. 12 is an enlarged fragmentary View indicating details of construction of the upper slice lip of the head box of FIGS. 1-ll;

FIG. 13 is a fragmentary view looking from left to right in FIG. 12;

H6. 14 is a fragmentary section on the line 14-44 of FIG. 11;

FIG. 15 is an enlarged fragmentary section on the line 1515 of FIG. 1 illustrating parts of the adjustable mounting for the front wall of the head box;

FIG. 16 is a diagram showing a control system for regulating the liquid level and pressure conditions in the head box of FIGS. 1-15;

FIG. 17 is a fragmentary perspective View showing the bracing structure for the back wall of the head boxof FIGS. 1-15; and

FIG. 18 is a vertical section showing another construction of head box in accordance with the invention.

Referring to the drawings, which illustrate preferred embodiments of the present invention, the flow chamber of the head box is defined by a front wall 20,

side walls

21 and 22, a back wall 23, a bottom wall 24, and a top wall 25 which includes a downwardly sloping front portion 26, and all of these walls are shown as clad with a layer 27 of stainless steel or other suitable material providing a surface of great smoothness. The front wall 20 includes an upper slice lip 30 which cooperates with the lower slice lip 31 at the front of the bottom wall 24 to define the slice outlet 33 through which the stock is discharged onto the forming, wire 34 as itpasses over the breast roll 35, and thewall 20 is adusjtable vertically and also in the direction of wire travel to vary the configuration of outlet 33 as described in detail hereinafter.

The stock enters the flow chamber through an inlet opening 36 extending across the back of the bottom wall 24 to provide an upward entering flow of stock which flows generally horizontally to the front of the head box for discharge through the slice outlet 33. The head box is totally enclosed at the top thereof but is designed to operate with an air space within its upper part and above the level of stock flow therethrough, and a series of shower pipes 37 are arranged in this air space for continuously showering the top of the stock flowing through the box. In addition, provision is made for establishing such positive or negative pressure conditions within this air space as to produce a desired total pressure effective on the outlet 33 without the necessity of corresponding variations of the liquid level Within the flow chamber. In other words, the pressure may be super-atmospheric to provide a higher elfective head than the static head of stock, or it may be sub-atmospheric to provide a lower total pressure than would exist at the maintained stock level in an open head box.

Special provision is made in accordance with the invention for assuring uniform cross sectional dimensions for the flow of stock entering through the inlet opening 36 across the entire width of the head box. Referring to FIGS. 1 and -8, the stock is delivered to the opening 36 by way of a vertical inlet passage 46 defined by the front and rear Walls 41 and 4-2, each reinforced with a plurality of I-beams 43. This inlet passage section is in turn mounted on a base structure indicated generally at 44 and defining an explosion chamber 45 into which stock is delivered by a plurality of supply pipes 46 connected thereto at closely spaced intervals across the entire Width of the machine. Stock entering from the pipes 46 is therefore forced to change direction with substantial tumbling agitation for thorough intermixing before it enters the passage 40.

When the paper machine is operating at high speed, it is important to maintain a uniform upward flow through the inlet passage 4t) across the entire width of the machine, and this is a requirement of increasing magnitude in relation to the width of the machine which is solved by the present invention. Referring particularly to FIGS. 5-8, a pair of

throat members

51 and 52 are mounted on the

respective passage Walls

41 and 42 to introduce a restriction in thepassage 40. Each of these throat members is trapezoidal, and preferably frustoconical, in cross section to present converging and diverging

passage portions

53 and 54 on either side of the restriction 55 through which all of the stock must pass upward to the head box. A rectifier roll 56 such as a perforated cylinder is mounted within, the passage portion 54 to quiet turbulence in the stock as it emerges from restriction 55 and the passage portion 54.

The inner wall of each of these

throat members

51 and 52 is formed from a single plate 60 for maximum smoothness, and the interior of the throat member is provided with multiple bracing plates or

ribs

59, 61, 62 and 63 to form a rigid structure seating on the inner surface of the

adjacent wall

41 and 42. The two throat members are located with their shorter parallel sides 64 aligned across the passage to form the restriction 55, and a plurality of spacer fins 65 are received between the opposed sides 64 within the restriction 55 and in spaced relation across the side of the inlet passage. As shown in detail in FIGS. 7 and 8, each of the spacer fins 65 is of essentially solid section and is provided with a flared peripheral edge 66 for smooth interfitting with the inclined sides of the plates 60 to establish correspondingly smooth flow conditions therepast.

Each of the spacer fins 65 is provided with a pair of through holes 67 aligned with corresponding holes in the walls 64 to receive through bolts 68. These bolts in turn extend to the outer surface of

walls

41 and 42 and receive nuts 69 which are tightened to secure the

walls

41 and 42 together in compressing relation with the

throat members

51 and 52 and the spacer fins 65. This causes the

walls

41 and 42 to be rigidly braced in the uniformly spaced reration established by the throat members and the fins 65 to maintain a uniform flow area through the restriction 55 and also to maintain the

walls

41 and 42 in uniformly spaced relation across the entire width of the head box in the portion thereof between the restriction 55 and the inlet opening 36. This condition is assured because the walls 1 and 42 are tied directly together through rigid braces in such manner as to maintain the desired uniform spacing even against high internal pressure and Without the necessity for massive outside bracing or supporting structure.

As noted, the stock enters the back of the head box in upward flow and at relatively high velocity when the paper machine is operated at high wire speeds, and it is accordingly important to eifect substantially complete quieting of the turbulence of this flow while maintaining uniform flow and fiber distribution conditions across the entire length of outlet 33 with minimum possibility of flocculation. These desired conditions are established in accordance with the present invention by a novel arrangement of rectifying rolls 7175 which are located between the inlet 36 and outlet 33 and cooperate to provide maximum assurance against the passage of unrectified roll stock through the outlet. As shown in FIG. 1, these rolis are arranged in two groups, the first group 71-73 being located generally in the middle of the flow chamber between the inlet and outlet, and the sec- 0nd group comprising a pair of

rolls

74 and 75 being located adjacent the outlet 33.

The rectifying roll 71 nearest the inlet 36 is maintained closely adjacent the bottom wall 24, Within approximately /2 inch of the wall, to provide running clearance while minimizing the possibility of the passage therepast of unrectified stock. The possibility of this result is further minimized by the provision of a flow-directing bafile 77, which may be a formed portion or extension of the bottom Wall 24, located just ahead of the roll 71 and extending above the level of the wall 24 in such manner as to direct the upwardly flowing stock toward the periphery of roll 71 rather than permitting some of this stock to flow beneath this roll. At the same time, the bafile 77 should be constructed to minimize the possibility of fiber deposit therein, and this result is obtained by forming its upper surface portion 78 which is closest to roll 71 with a cylindrical curvature approximately concentric with roll 71 so that rotation of the roll will maintain a scouring effect on this surface 78.

The two rolls 72 and 73 are each mounted in a position higher than and forwardly of the roll 71 such that substantial overlapping of the peripheries of adjacent rolls in the path of horizontally flowing stock and also sufficient overlapping of adjacent rolls in a vertical direction to prevent substantial space therebetween. For example,- satisfactory results have been obtained with the axis of each roll spaced above the axis of the next lower roll by a distance approximately equal to the radius thereof to provide approximately 50% overlapping of the rolls in a horizontal direction, and with the horizontal spacing of the axis of adjacent rolls being sufficient to maintain running clearances of the order of /2 inch between the peripheries thereof. As shown, this establishes the axes of the several rolls in a plane extending at substantially 30 to the horizontal.

This overlapping arrangement of rolls 7173 is of major importance in accomplishing the desired high uniformity of sheet formation especially on paper machines of the great widths indicated above, for a variety of reasons. For example, it is essential that some running; clearance be maintained between the peripheries of adjacent rolls in order to eliminate the possibility of fric-- tional contact therebetween and also to prevent possible. crushing of the fiber in the hips of the rolls, and it iscustornary to provide a clearance of the order of /3 inch therebetween. However, if such rolls are arranged in a stack extending transversely of the direction of' the stock flow therepast, an unexpectedly large proportion of the stock will pass between the rolls in unrectified condition. For example, tests with a pair of rolls 18 inches in diameter and approximately /2 inch apart indicate that as much as 30% of the total flow will take place between the rolls rather than therethrough.

The arrangement of the rolls in overlappingrelation provided by the present invention offers maximum assurance against the passage of unrectified stock between the rolls, together with other advantages. Thus it is a practical necessity in paper machines of great widths that the rectifying rolls be of suflicient size and diameter to resist sagging. At the same time, maximum uniformity of the rectifying action is obtained with rolls of relatively small diameter, since with a very large roll, the stock flow across the center of the roll will be subjected to quite difierent effects from the flow across portions of the roll spaced away from the center. Tests indicate that an optimum roll diameter from the standpoint of compromising both of these conditions is approximately 18 inches. On the other hand, it is desirable to maintain the stock level within the box as low as practicable for the desired high speed, while also assuring an adequately slow flow rate of stock through the box for proper control of turbulence and the establishment of uniform flow and fier distribution conditions.

Consideration of all the above factors dictates that a plurality of the rolls should be used at the location of rolls 73.'73, and the overlapping arrangement of these rolls provides the maximum assurance of essentially uniform rectifying action While making it possible to use rolls of adequately large size for stability and to maintain a desired relatively low level of stock in the flow chamber. In addition, the progressively offset arrangement of the rolls 71-73 reduces the flow path from the uppermost rolls to the slice outlet 33, particularly as compared with a vertical stack of rolls in t is location, and thus minimizes the possibility of flocculation with can talze place over a longer flow path in the absence of the rectifying action.

Each of the rolls 71- 75 is provided with a pair of individually ad, .able mountings in the side walls of the head box which makes it possible to adjust each roll in both vertical and horizontal directions. One such mounting is illustrated in FIGS. 3 and 4 in association with the roll 74, which is shown as a perforate cylinder 74 provided with an end spider 59 md stub shaft iii. The mounting shown in FIGS. 3 and 4 is on the front or control side of the head box, and there is a similar mounting at the drive side which also incorporates a suitable: driving connection for the roll.

Referring to FIG. 3, a reinforcing plate 84 is welded to the side wall 22, an eccentric cam 85 is journaled in both plate 534- and the side wall. A plurality of clamps releasably secured by bolts 87 to the plate 3- and overlap the front of a flange 83 on cam 35 to secure the cam in fixed relation to plate 34. When clamps 86 are loosened, cam 55 can be rotated in plate 84- by means of worm gear teeth fit) on earn 85 which mesh with a worm 91 mounted by a bracket 2 on plate (54- and provided with an extended shaft for manual operation.

A second eccentric cam 5 is journaled in cam 85 and is similarly secured thereto by clamps $5 and bolts W cooperating'with a flange 98 on cam 95. Worm gear teeth ass on cam 95 mesh with a worm ltil which is mounted by a bracket 1&2 on cam 85 and is provided with extended shaft 363. The stub shaft 81 extends freely through cam 95' and is mounted thereon at its outer end -y a suitable bearing assembly res. In addition, the outer end of cam 9.5 is slotted and counterbored to receive suitable packing 1 3 6 and a gland bolted on the end of cam d5 to seal the connection between the cam 95 and shaft 81.

With this construction, whenever the clamps 86 are loosened, the cam 35 can be rotated by means of worm 91 to cause an adjustment of the axis of roll 74- about the rotational axis of cam 35. Similarly when clamps are loosened, cam $5 can be rotated in cam by means of worm 1M to produce similar adjustment of the axis of roll 7 4} about the rotational xis of can 95. These two adjustments can be used selectively to augment or to offset each other and thus permit adjustment of the roll axis in all directions through a range equal to the sum of the eccentricities of the two cams. Satisfactory results have been obtained with rolls of 18 inches in diameter as noted above with each cam having a throw of 1.5 inches to give a possible total adjustment of the roll axis of 3 inches.

The above adjustments of the rectifier rolls can be carried out without emptying the head box and even while the machine is in operation, since it is necessary only to loosen the clamps sufficiently for movement of the cams, and this can be done without appreciable leakage of stock from within the head box. The adjusted position of roll '74 is readily indicated by means of an indicator disk lit? secured on the end of shaft 31 by a bolt ill. With this of the same diameter as its associated roll and with a similar disk secured to each other roll, the positions of the several disk will show the relative positions of the rolls themsel es within the head box.

The rolls 7d and 75 adjacent the slice outlet 73 are mounted in accordance with the invention in a particular spaced relation with the outlet As shown, the roll 74 is close to the bottom wall, with preferably no more than running clearance of the order of /2 inch therebetween. The other roll is mounted forwardly of and at a higher level than the roll 74, and preferably in similarly closely spaced relation with the front wall 2%. In addition, the two rolls are not uniformly spaced from the outlet 33, but instead the roll 75' is located closer to the outlet by a distance such that a line passing between the two rolls normally to a connecting line between their axes will intersect the bottom wall at a position spaced rearwardly from the outlet.

The purpose of the above arrangement of the

rolls

74 and 75 is to provide maximum assurance against the passage of stock through the outlet 33 Without subjection to the rectifying action of these rolls. Thus having in mind the above facts with respect to the tendency of stock to pass between rather than through a pair of adjacent rectifier rolls, it will be apparent that there must be some appreciable proportion of the stocx which will slcid between the lower roll 74 and the bottom wall of the head box, and there will also be some such passage or" stock between the two rolls as well as between roll 75 and the front wall 2-". However the stool; passing between the two rolls will follow essentially a direction extending normally of a line connecting the axes of the two rolls and will therefore intersect stock passing be low the roll "74 at a position spaced rearwardly of the outlet 33 instead of discharging directly outwardly through the slice outlet as would be the case if the two rolls were equally spaced from the outlet or from the tip of either slice lip. Therefore, this arrangement of rolls 74 and '75 not only provides for effective overlapping of the rolls in the path of a major portion of the approach ilow of stock to the outlet 33, but also the directional effect of the rolls on stock which does not traverse them will produce suliicient controlled turbulence to eliminate possible condi ons of flocculation in the stock which is not subjected to the rectifying action of passage through the rolls.

Both of the rolls 74' and 75 are provided with a justable mountings as described in connection with FIGS. 3 and 4, and this is important in conjunction with the mounting of the front Wall 20 for adjustment lengthwise of the wire. These adjustable mountings for the rolls i4 and 75 make it possible to adjust the roll 75 to the proper closely spaced relation to wall 2b in all its adjusted posi- 7 tions while also maintaining desired relative positions of the two rolls with respect to each other and to the fixed lower slice lip 31, with particular reference to the prevention of straight through flow between the two rolls to the outlet 33 as described above.

The adjustable mounting for the front wall 24 is shown inFIGS. 1 and 15. Referring to FIG. 15, the front wall 20 is provided with a reinforcing beam structure indicated generally at 129 which includes side wall portions 121 (FIG. 11) extending in close relation with the

main side walls

21 and 22 of the head box. A bracing block 123 is provided in the upper corner of the beam structure 12% between the wall 29 and each of the side walls 121, and a web 124 is mounted near but inwardly spaced from each block 123.

Each block 123 and rib 124 cooperate to support a pivot pin 125 which extends outwardly into the

adjacent side wall

21 or 22 and has its outer end journaled in a cross head block 13% which is mounted for sliding movement between a pair of gibs 131 bolted to the opposed inner faces of two of the plates 132 which reinforce the side wall of the head box. The block 15% is held on the pin 125 by a bolt and washer 133, and a spacer collar 13-? is located between the inner end of block 130 and the side wall 121. The pin 125 is therefore guided for vertical movement by means of the block 13%, and this movement is effected and controlled through a connecting rod 135 which receives the inner end of the pin 125 and has its upper end connected with an adjusting motor indicated generally at 5.36 in FIG. 1.

The front wall 2i) and its beam structure 120 may also be pivoted on the pins 125 to swing the upper slice lip 30 in the direction of the wire. This movement is effected and controlled by a pair of toggle links 14% and 141 and a cooperating adjusting screw 142. The link 14% is pivoted on the fixed side wall of the box, the link 1141 is pivoted to the Wall 121, and the screw 142 is pivoted to the inner ends of the two links and is secured in a horizontal rib portion 145 of the side wall 21 by means of a pair of

nuts

146 and 147.

With this arrangement, vertical adjustment of screw 142 will change the angular relation of the links 144} and 141 and thus cause the entire front wall structure to pivot on the pins 125. This provides a rigid adjusting mechanism for the front wall, and provision is also made for positively locking the wall in adjusted position by means of a pair of

clamps

150 and 151 to minimize transmission of vibrations in use. The clamp 15% is secured to the side wall 121 by the bolt 152 which pivots the link 14-1 on wall 121 and extends through a slot in the wall 21. The clamp 151 is similarly secured to the wall 121 by a bolt 153 extending through a slot in the wall 21. This entire adjusting and clamping structure is duplicated at the other side of the head box.

The above adjustments of the front Wall 2% determine the extent of the slice outlet 33, and the upper slice lip 30 also is provided with a slice bar 164) which is adjustable into accurate parallelism with the lower slice lip 31. Referring to FIGS. 12 and 13, the lower edge of the slice lip 34) is finished on its outer side to receive the slice bar 168 slidably thereon, and the slice bar is held frictionally against the slice lip by means of a plurality of generally fiat springs 161. These springs 161 are mounted for sliding movement between a bar 162 and guide plate 163, both of which are bolted to the slice lip 30 with suitable spacers therebetween which provide a slidable mounting for the springs.

The lower end of each spring 161 is received in a slot extending across the back of the bar 161 and its upper end is similarly received in a slot along the under side of an adjusting block 165 which is also mounted for sliding movement along the outside of the slice lip 30, there being one of these blocks for each spring 161. An adjusting rod 166 is threaded or otherwise secured to each block 165, and its upper end is connected to an adjusting mechanism indicated generally at 167 in FIG. 1 which is manually operable to raise or lower the adjusting rod. With a large number of these adjusting units and springs provided, for example approximately 50 with a slice lip of the order of 306 inches in width, accurate adjustment of the bar 1613 is readily obtained and maintained.

Special provision is made for maintaining a seal against internal pressure between the movable front wall 20 and the adjacent stationary portions of the head box. Referring first to FIGS 1 and 2, a seal is provided between the upper portion of the front wall 29 and the adjacent front portion 26 of the top wall 25. A pair of angle shaped

bars

170 and 171 extend across the front of the part 26 and form a channel which receives an extended solid rubber sealing member 172 and is provided with a connection 164 for a supply source of air pressure to inflate tube 163 and thereby to provide uniform pressure against the inner end of member 162 effective to urge the latter into maintained sealing engagement with the front wall 26. Since this sealing mechanism is located near the top of the front wall Zii, pivotal adjustments of the latter will not appreciably afiect the pressure on the sealing member 172.

A pneumatic seal is also provided between the side edges of the front wall 21) and

side walls

21 and 22 of the head box. Referring particularly to FIG. 15, a slot 175 is provided in each of the side walls 121 and 122 in line with the wall 2%}, and a pneumatic tube 176 is arranged in each of these slots for inflation into maintained sealing engagement with the

adjacent wall

21 or 22 of the head box. This slot and tube also extend downwardly across the opposite side edges of the upper slice lip 31 as shown in FIGS. 11 and 14, and the lower end of the slot in the slice lip 34 is filled with a solid rubber sealing member 177.

The lower end of the tube 176 and the sealing member 177 at each end of the front wall cooperate with additional special sealing means including a pressure pad 2% of rubber or fiber-reinforced plastic material which forms a checking piece mounted as an insert in a cheeking piece bracket 222 bolted at 203 to the lower end of each side wall, which is shown as the side wall 22 in FIGS. 10 and 11. This bracket extends inwardly of the flow chamber to a position beyond the back edge of the lower slice lip 31, and it also cooperates with the clamping strip 205 and a rubber sealing wedge 20% to hold the apron cloth 216 which lies over the lower slice lip and a portion of the breast roll 35.

Referring to FIG. 9, the lower slice lip 31 is bolted to the front edge portion of the bottom Wall 24, which is milled at 211 to form a step for receiving the back portion of the lip, and an additional step 212 in the bottom wall receives the clamping strip 205. The apron cloth 216 lies over the lower slice lip 31 but extends underneath the front edge of the clamping strip 265 and is clamped thereby against the slice lip through screws 213. Bores 21dand 215 in wall 24- and the clamping strip 2135 cooperate to receive a drift pin for forcing the clamping strip into closely seated relation with the back of the step 212 to prevent a possible obstructionat this point to smooth flow of stock along the bottom of the flow chamber. Jack screws 216 extend through the wall 24 and are operable to release the front edge of the strip 2%5 from clamping engagement with the apron cloth when the latter is to be changed.

The rubber wedge 21% forms the seal between the side and bottom walls of the head box in the portions where the side edges of the apron cloth 210 emerge from the flow chamber. Referring particularly to FIG. 11, the bracket 2132 includes near its lower edge an outer face 229 which is beveled at approximately 45 to the vertical to receive the rubber wedge 296 thereon, and the wedge is clamped thereto by means of metal clamping strips 9 221 and screws 222. As shown in FIG. 9, the wedge 2172 is contoured along its lower edge to fit the lip 31 and also the sealing strip 205 to provide a seal along the entire junction between these parts and the side wall structure.

The rubber wedge 206 terminates at the outer end of the lower slice lip 31, but the beveled portions of the bracket 2%2 extends for a substantial distance beyond this point as shown in FIG. 9 and provides the support for the strip 225 which acts as a deckle in this area. As shown in FIG. 10, the strip 225 is held on the bracket similarly to the rubber wedge by means of screws 222 and a clamp strip 226. Also, this part of the bracket 202 carries an additional right-angled bracket 230 in which are mounted a plurality of adjusting screws 232 which bear against the outer face of that portion of the bracket N2 which carries the pressure pad 2%. The adjusting screws 232 are shown as provided with lock nuts 233 to secure them in adjusted position, and they can be loosened to release the pressure between the upper slice lip and the pressure pad 200 during adjusting movement of the front wall 26.

in the operation of the head box of the invention, it is preferred that the liquid level of the stock in the flow chamber be maintained at all wire speeds just above the uppermost of the several rectifier rolls, namely the roll 73 in FIG. 1, and that the spouting velocity of the stock be established by appropriate regulation of the air pressure within the space above the liquid level. This makes it possible to operate at effective total pressures which are greatly in excess of the static head of stock, and also which may be substantially lower than the stock head, and FIG. 16 shows diagrammatically a control system which may be used in conjunction with this head box to provide thehe operating characteristics.

In PEG. 16, the stock supply system includes a pump 25% which receives fresh stock from the supply line 251 for mixture with the white water from the wire pit 252, and the discharge from pump 25% reaches the inlet passage 40 by way of a pair of

parallel lines

253 and 254. The line 253 includes the main stock control valve 255 which is normally set manually to pass somewhat less than the full volumetric rate desired for the selected wire speed, and the balance of the stock is provided under accurate control by a valve 256 in the line 254. FIG. 16 mso shows a line 257 connecting the discharge side of pump 250 back to the main stock line 251 and provided with a hand valve 258 for effecting measured predilution of the fresh stock with the mixture from pump 250.

The valve 256 is shown as operated by air pressure and is continuously controlled to maintain the desired stock level within the head box. The level controller 26% is adjustable to establish the stock level to be maintained, and it operates in conjunction with a monometer 2 51 connected by a line 262 with a location in the head box which is substantially lower than the level to be maintained. The other side of the monometer 261 is connected by

lines

253 and 264 with a location in the head box substantially above the liquid level to be maintained, and the

lines

262 and 263 are both shown as having connections 265 for providing a measured supply of filtered fresh water to prevent fiber from working back into any of these lines.

The controller 26% is connected at 266 with the valve 255 and at 267 with the air pressure supply, and it also has a pressure connection 268 with the monometer 261. In operation, the monometer 261 senses the difference in pressure between its two connections to the head box and transmits the resulting signal .to the controller 269. The controller in turn compares the actual level indicated by this signal with the desired stock level for which it has been pre-set, and if these levels are different, it changes the air pressure in the valve 256 and causes this 19 valve to open or close to the extent required to re-establish the desired stock level. Since the stock level is usually kept the same irrespective of the total pressures in the box, there will be little occasion for altering any of the manual settings in this part of the control system.

The pressure in the air space above the stock level is controlled by a controller 276 and associated monometer 271 which is connected on one side by a line 272 with the line 264 from the upper part of the head box and which also has a pressure connection 273 with the controller and a connection 274 with the air pressure supply. The other side of the monometer 271 is connected with a standpipe 275 which is at least as high as the static head equivalent to the maximum total pressure to be established within the head box. The line 276 between standpipe 275 and the monometer 271 is also equipped with a connection 277 providing a measured supply of filtered fresh water.

T he standpipe 275 is provided with a plurality of drain lines 279 at spaced distances apart which are each somewhat less than the range of the controller 271). For example, if the controller has a range from 0 to 60 inches, the drain lines 2% may be spaced at 50 inches apart, and each drain line is provided with a separate control valve which may be a solenoid valve for convenient remote operation. One of the valves 28%, identified as 23611, is the zero inch valve, and its drain line is carefully aligned horizontally with the connection between the line 26 and the interior of the head box.

The controller 270 has a connection 234 with an air operated valve 285 which controls the connecting line 236 into the top of the head box from the air pressure supply. This line 286 is also provided with a manually operated bleed valve 287 leading to the atmosphere, and this valve is normally set to bleed pressure at a slow rate in order to provide for rapid lowering of pressure within the head box whenever such a result might be desired. The head box is also provided with a connection 2% and control valve 291 leading to a source of vacuum which is employed as described hereinafter when the head box is to operate with sub-atmospheric pressure in the air space above the stock level.

With this control system, if the desired spouting velocity requires a positive pressure in the upper part of the head box which is in the range of 0 to 50 inches of water, the drain valve 23% is closed, and all the other drain valves are opened. The controller 270 is then set for the desired pressure to be maintained, and it operates similarly to the controller 266 by comparing the actual pressure on the monometer through the connection 272 with the desired pressure. If the two are different, the controller operates through the connection 284 to change the setting of the air valve 235 until the correct pressure has been re-established in the head box. Thus if the actual pressure is too high, the valve 2S5 will be closed until sufficient pressure has bled ofi through the vent valve 2%7, and similarly if the pressure is too low, the valve 285 will be temporarily opened to a greater extent.

For pressures in excess of 50 inches of water to be maintained by the controller 276, the other drain valves 23%) are successively closed in order to apply back pressure to the controller in increments of 50 inches of water. Thus for pressures in the range of 50 to inches of water, the valves 23% and 2%(ib will be closed but the other valves will remain open, and the operation of the system will be the same as previously described. If the added pressure is to be between 100 and inches of water, the valve 2800 is also closed, etc.

If it is desired to run with the slice pressure at a lower value than the minimum which can be obtained at the desired maintained stock level within the head box, this pressure condition can be established by applying a vacuum to the head box through the connection 290 and valve 291. For such operating conditions, the valve 287 is closed, and all of the valves 280 are opened including the valve 23317 which represents a -50 inches of water. The controller 276 is then set to' provide the proper olfsetting pressure for the minus pressure applied to the monometer 281 through the connection 233, and thereafter the operation will be the same as for the other conditions described, with the liquid level being regulated to remain substantially even With the uppermost rectifier roll While the total effective pressure is maintained by regulation of the vacuum in the upper part of the flow chamber. In other words, if the vacuum produced through the connection 290 is in excess of that desired, the controller 276 will open valve 285 to admit sufficiently more air to reduce the vacuum to the desired level. If the vacuum is too low, the reverse occurs and the added air supply will be reduced until the desired vacuum is re-established. Alternatively, the supply line to the valve 285 could be connected to atmosphere rather than to the air pressure supply.

Under all operating conditions and the full range of pressures and wire speeds as outlined above, the head box of the invention will produce a sheet of uniformly high quality, and in particular it will deliver a flow of stock to the forming wire which is free of flocculation effects and other non-uniform conditions of flow and fiber distribution. The arrangement of the rectifier rolls within the head box in accordance with the invention provides for substantial variations of the how area of the slice outlet and also of the fiow velocities through the box while still maintaining proper rectifying action, and this is true over the entire desired range of Wire speeds. The invention further makes it possible to vary conditions such as the spouting velocity of the stock, the size of the slice outlet, and the adjusted positions of the several rectifier rolls without emptying the head box or otherwise interfering with operation of the machine, and thus it greatly reduces the possible down-time for the machine and correspondingly contributes to the economical advantages of this head box.

in addition to the features already described, the invention provides further supporting structure for the inlet section of the head box which is highly advantageous at maximum speeds of operation in minimizing vibration of the head box walls. Referring to FIGS. 1 and 17 a Warping beam 360, shown as a fabricated box beam, extends across the back of .the head box just below the level of the bottom Wall 24 and is supported by suitable pedestals 301. On either side of the head box, a pair of tie rods 303 extend from this beam 380 to the supporting structure 3495 below the bottom Wall 24 to establish a rigid connection therebetween.

Along the back of the head box, the back Wall 23 is provided with a plurality of spaced vertically extending bracing ribs 310, and between each rib 310 and the near face of the beam 36%) is positioned a cooperating set of tapered

wedges

311 and 312 each having an adjusting screw 313. This construction therefore makes it possible to effect individual bracing adjustment between the beam 3% and each rib 310, and since the ends of the beam see are tied rigidly to a portion of the head box on the opposite side of the inlet passage as, the result is a strong overall bracing of the back wall 23 sufficient to withstand even the vibrations which tend to be created when the stock flow through the head box is at the high rate necessary to sustain wire speeds as high as 3000 feet per minute.

FIG. 18 shows a somewhat simplified head box construction which embodies many of the features of the invention described above. The flow chamber in this head box is defined by a front wall 32%,

side walls

321 and 322, a bottom wall 324 and a wall 325 which extends in a continuous curve from the front wall 32% to form both the top and back walls of the head box. The front wall 325 includes an upper slice lip 33% which cooperates with the lower slice lip 33-1 at the front of the bottom wall 324 to define the slice outlet 333, and the front wall 32% is shown as adjustable vertically by means of the adjusting drive mechanism indicated generally at 335. FIG. 18 also shows an access opening 336 in the top wall and the system of shower pipes 337 for continuously showering the top of the stock fiowing through the box.

The stock inlet system includes an explosion chamber 34% into which stock is delivered by a plurality of supply pipes 341 connected in spaced relation across the back of the head box. From the explosion chamber 340, the stock flows upwardly through a narrow inlet throat 3-2 3, and the inlet passage 345 defined by

walls

346 and 34? above this throat diverges upwardly to form a venturi passage leading directly into the back of the flow chamber. The arrangement of the wall 325 in continuously forwardly curving relation from the upper end of the bacl: wall 346 of the venturi passage 345 is ad-- vantageous as providing a continuous forwardly directing action on the up-fiowing stock which effectively prevents the possibility of the development of dead spots at the back of the head box. FIG. 18 also shows that the supporting structure on either side of the throat 343 and ventu-ri passage 345 includes multiple brace plates E E-355 for maintaining the walls defining these passages in rigidly braced relation.

The system of rectifier rolls within the head box of FIG. 18 is similar to that already described in connection with PEG. 1, and they may be similarly mounted in the side walls of the head box for adjustment as already described. More specifically, there is a roll 360 mounted in the venturi passage 345, and three

rolls

361, 362 and 363 are located generally in the central part of the fiow chamber with their axes defining a plane which is inclined forwardly at an angle of the order of 35 to the bottom wall 324-. An additional two

rolls

364 and 365 are mounted adjacent the outlet passage 333 in the same relation therewith as already described in connection with the rolls '74 and 75. The arrangement and adjustable mountings for these rolls 36 l'365 are therefore in accordance with the same principles discussed in con nection with the rolls 7175 and perform the same advantages in the operation of this head box, and this head box may be controlled in operation by essentially the same control system already described in connection with FIG. 16.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A head box for a paper making machine comprising a pair of side walls cooperating with front and back walls and a bottom wall to define a flow chamber, an upper slice lip carried by said front wall and cooperating with said bottom wall to define a slice outlet from said chamber, means forming an inlet for stock at the back of said chamber to provide for generally horizontal flow of the stock toward said front wall for discharge through said outlet, a plurality of rectifier rolls mounted within said chamber in spaced relation with said inlet and said outlet, one of said rolls being located with the periphery thereof closely adjacent said bottom wall, each other saidroll being spaced higher than and forwardly of the adjacent lower said roll by distances less than the diameter thereof to provide substantial overlapping of said rolls in the path of said horizontally flowing stock, a pair of additional rectifier rolls located adjacent said outlet, means mounting one of said additional rolls closely adjacent said bottom wall and spaced rearwardly from said front wall, and means mounting the other said additional roll closely adjacent said front wall in forwardly in? and upwardly spaced relation with said one additional roll and withthe periphery thereof closer to said outlet than the periphery of said additional roll such that a line passing between said pair of rolls and normal to a connecting line between the centers thereof will intersect said bot-tom wall at a position spaced rearwardly from said outlet.

2. A head box for a paper making machine comprising a pair of side walls cooperating with front and back walls and a bottom wall to define a flow chamber, an upper slice lip carried by said front wall and cooperating with said bottom wall to define a slice outlet from said chamber, means forming an inlet for stock at the back of said chamber to provide for generally horizontal flow of the stock toward said front wall for discharge through said outlet, a plurality of rectifier rolls of substantially equal diameter arranged within said chamber in spaced relation with said inlet and said outlet, one of said rolls being located with the periphery thereof closely adjacent said bottom wall, means for mounting each other said roll on said side walls with the axis thereof spaced forwardly of the axis of the adjacent lower said roll by a distance sufiicient to provide running clearance between the peripheries thereof and higher than said axis by a distance less than the diameter thereof to provide for substantial overlapping of said rolls in the path of said horizontally flowing stock, and additional rectifier roll means located adjacent said outlet.

3. A head box for a paper making machine comprising a pair of side walls cooperating with front and back walls and a bottom wall to define a flow chamber, an upper slice lip carried by said front wall and cooperating with said bottom wall to define a slice outlet from said chamber, means forming an inlet for stock at the back of said chamber to provide for generally horizontal flow of the stock toward said front wall for discharge through said outlet, rectifier roll means arranged within said chamber in spaced relation with said inlet and said outlet, a pair of additional rectifier rolls located adjacent said outlet, and means mounting said additional rolls in non-uniformly spaced relation with said outlet such that a line passing between said pair of rolls and normal to a connecting line between the centers thereof will intersect said bottom wall at a position spaced rearwardly from said outlet.

4. A head box for a paper making machine comprising a pair of side walls cooperating with front and back walls and a bottom wall to define a flow chamber, an upper slice lip carried by said front wall and cooperating with said bottom wall to define a slice outlet from said chamber, means forming an inlet for stock connecting with the back of said chamber from below to provide for upward entering flow of the stock into said chamber, a plurality of rectifier rolls mounted within said chamber in spaced relation with said inlet and said outlet, one of said rolls being located with the periphery thereof closely adjacent said bottom Wall, each other said roll being spaced higher than and forwardly of the adjacent lower said roll by distances less than the diameter thereof to provide substantial overlapping of said rolls in the path of said horizontally flowing stock, a pair of additional rectifier rolls located adjacent said outlet, means mounting one of said additional rolls closely adjacent said bottom wall and spaced rearwardly from said front wall, means mounting the other said additional roll closely adjacent said front wall in forwardly and upwardly spaced relation with said one additional roll and with the periphery thereof closer to said outlet than the periphery of said additional roll such that a line passing between said pair of rolls and normal to a connecting line between the centers thereof will intersect said bottom wall at a position spaced rearwardly from said outlet, a top wall extending from said back wall to said front wall to enclose said chamber, means for supplying pressure air to said chamber to maintain a cushion thereof above the stock flowing therethrough, and said back and top walls being continuously curved upwardly and forwardly from said inlet to direct all of said entering. stock toward said rolls and said outlet.

5. A head box for a paper making machine comprising a pair of side walls cooperating with front and back walls and a bottom wall to define a flow chamber, an upper slice lip carried by said front wall and cooperating with said bottom wall to define a slice outlet from said chamber, means forming an inlet for stock connecting with the back of said chamber from below to provide for upward entering flow of the stock into said chamher, a plurality of rectifier rolls of substantially equal diameter arranged within said chamber in spaced relation with said inlet and said outlet, one of said rolls being located with the periphery thereof closely adjacent said bottom wall, means for mounting each other said roll on said side walls with the axis thereof spaced forwardly of the axis of the adjacent lower said roll by a distance sufiicient to provide running clearance between the peripheries thereof and higher than said axis by a distance less than the diameter thereof to provide for substantial overlapping of said rolls in the path of said horizontally flowing stock, additional rectifier roll means located adjacent said outlet, a top wall extending from said back wall to said front wall to enclose said chamber, means for supplying pressure air to said chamber to maintain a cushion thereof above the stock flowing therethrough, and said back and top walls being continuously curved upwardly and forwardly from said inlet to direct all of said entering stock toward said rolls and said outlet.

6. A head box for a paper making machine comprising a pair of side walls cooperating with front and back walls and a bottom wall to define a flow chamber, an upper slice lip carried by said front wall and cooperating with said bottom wall to define a slice outlet from said chamber, means forming an inlet for stock connecting with the back of said chamber from below to provide for upward entering flow of the stock into said chamber, rectifier roll means arranged within said chamber in spaced relation with said inlet and said outlet, a pair of additional rectifier rolls located adjacent said outlet, means mounting said additional rolls in non-uniformly spaced relaton with said outlet such that a line passing between said pair of rolls and normal to a connecting line between the centers thereof will intersect said bot tom wall at a position spaced rearwardly from said outlet, a top wall extending from said back Wall to said front wall to enclose said chamber, means for supplying pressure air to said chamber to maintain a cushion thereof above the stock flowing therethrough, and said back and top walls being continuously curved upwardly and forwardly from said inlet to direct all of said entering stock toward said rolls and said outlet.

References Cited in the file of this patent UNITED STATES PATENTS 833,275 White Oct. 16, 1906 1,727,928 Berry Sept. 10, 1929 1,909,150 Bell-Irving et a1 May 16, 1933 2,148,613 Frost Feb. 28, 1939 2,156,445 Baxter May 2, 1939 2,264,941 Kellett et al. Dec. 2, 1941 2,281,293 Lang Apr. 28, 1942 2,521,261 Smith et a1. Sept. 5, 1950 2,615,374 Malkin Oct. 28, 1952 2,664,033 Hornbostel et al. Dec. 29, 1953 2,699,096 Hornbostel I an. 11, 1955 2,711,935 Miles June 28, 1955 2,718,824 Hornbostel Sept. 27, 1955 2,728,272 Hisey Dec. 27, 1955 2,736,246 Crittenden et al. Feb. 28, 1956 (Qther references on following page) 15 UNITED STATES PATENTS Hornoostel Feb. 28, 1956 Stewart June 12, 1956 Lee Dec. 23, 1958 5 Corbin et a1; J an. 27, 1959 Beachler' Nov. 6, 1959 16 FOREIGN PATENTS 28,159 Great Britain 1911 784,883 Great Britain Oct. 16, 1957v OTHER REFERENCES I Mal-don et a1.: Pulp and Paper Magazine of Canada,

October 1954, pp. 107-1216.

Claims

1. A HEAD BOX FOR A PAPER MAKING MACHINE COMPRISING A PAIR OF SIDE WALLS COOPERATING WITH FRONT AND BACK WALLS AND A BOTTOM WALL TO DEFINE A FLOW CHAMBER, AN UPPER SLICE LIP CARRIED BY SAID FRONT WALL AND COOPERATING WITH SAID BOTTOM WALL TO DEFINE A SLICE OUTLET FROM SAID CHAMBER, MEANS FORMING AN INLET FOR STOCK AT THE BACK OF SAID CHAMBER TO PROVIDE FOR GENERALLY HORIZONTAL FLOW OF THE STOCK TOWARD SAID FRONT WALL FOR DISCHARGE THROUGH SAID OUTLET, A PLURALITY OF RECTIFIER ROLLS MOUNTED WITHIN SAID CHAMBER IN SPACED RELATION WITH SAID INLET AND SAID OUTLET, ONE OF SAID ROLLS BEING LOCATED WITH THE PERIPHERY THEREOF CLOSELY ADJACENT SAID BOTTOM WALL, EACH OTHER SAID ROLL BEING SPACED HIGHER THAN AND FORWARDLY OF THE ADJACENT LOWER SAID ROLL BY DISTANCES LESS THAN THE DIAMETER THEREOF TO PROVIDE SUBSTANTIAL OVERLAPPING OF SAID ROLLS IN THE PATH OF SAID HORIZONTALLY FLOWING STOCK, A PAIR OF ADDITIONAL RECTIFIER ROLLS LOCATED ADJACENT SAID OUTLET, MEANS MOUNTING ONE OF SAID ADDITIONAL ROLLS CLOSELY ADJACENT SAID BOTTOM WALL AND SPACED REARWARDLY FROM SAID FRONT WALL, AND MEANS MOUNTING THE OTHER SAID ADDITIONAL ROLL CLOSELY ADJACENT SAID FRONT WALL IN FORWARDLY AND UPWARDLY SPACED RELATION WITH SAID ONE ADDITIONAL ROLL AND WITH THE PERIPHERY THEREOF CLOSER TO SAID OUTLET THAN THE PERIPHERY OF SAID ADDITIONAL ROLL SUCH THAT A LINE PASSING BETWEEN SAID PAIR OF ROLLS AND NORMAL TO A CONNECTING LINE BETWEEN THE CENTERS THEREOF WILL INTERSECT SAID BOTTOM WALL AT A POSITION SPACED REARWARDLY FROM SAID OUTLET.