|Publication number||US3628589 A|
|Publication date||Dec 21, 1971|
|Filing date||Jan 31, 1968|
|Priority date||Jan 31, 1968|
|Also published as||DE1904625A1, DE1966123A1, DE1966123B2|
|Publication number||US 3628589 A, US 3628589A, US-A-3628589, US3628589 A, US3628589A|
|Inventors||Kenneth B Latimer, John A Means, James Moran, Paul J Thoma|
|Original Assignee||Time Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (4), Referenced by (5), Classifications (9)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent  lnventors John A. Means Norwalk;
Kenneth B. Latimer, Westport; James Moran, Norwalk; Paul .1. Thoma, Westport, all of Conn.
Jan. 31, 1968 Dec. 21, 1971 Time Incorporated New York, NY.
[21 Appl. No.  Filed  Patented  Assignee 541 now SYSTEMS 3 Claims, 4 Drawing Figs.
 References Cited UNITED STATES PATENTS 3,309,264 1/1964 Parker et a1. 162/338 X 3,220,919 11/1965 Parker et a1. 162/343 3,328,236 6/1967 Burgess, Jr. et a 162/343 X 3,345,254 10/1967 Kilian 162/343 Primary Examiner-Reuben Friedman Assistant Examiner-T. A. Granger Att0rneyBrumbaugh, Graves, Donohue & Raymond ABSTRACT: Paper stock flows through a header, a first flat channel, flexible hoses, expansion pipes, pipes of changing cross section, a second flat channel, and a slice nozzle. The nozzle lips are substantially rigid, and conventional sizing across the nozzle orifice is obviated. The structure facilitates ejection of stock from the nozzle in a controlled manner so that the stock remains intact as a wide flat jet a substantial distance beyond the nozzle.
PATENTEU 00:21 is?! BEZHPW SHEET 1 [1F 2 lltllil i 1 I KENNETH LATIMER. B JAM MORAN &
ATTORNEYS eir PMENTEMEW 3,329,589
SHEET 2 [1F 2 INVENTORS JOHN A. MEANS;
K NETH B. LATIMER, J ES MORAN a PAUL J. THOMA fheir ATTORNEYS BACKGROUND OF THE INVENTION This invention relates to flow systems and, more particularly, to flow systems facilitating ejection of paper stock at high speed from a nozzle in a controlled manner so that the stock remains intact as a wide flat jet a substantial distance beyond the nozzle and in which conventional sizing of the nozzle is obviated. The term paper" is used in a generic sense to include paperboard and other paperlike products.
It is essential that a flow system for delivering paper stock to a paper machine wet end be capable of providing a uniform flow of stock from point to point across the width of the nozzle and from point to point in time. The stock must also be free of flocculations at the nozzle. To the extend that the flow system fails to meet these requirements, the resulting formed web of paper exhibits imperfections.
In conventional flow systems, the relation of one part to another tends to be haphazard, and extensive sizing of the nozzle orifices is necessary in an attempt to achieve uniformity in the formed web.
Conventional apparatus and methods are seriously deficient in a number of respects. For example, they fail to maintain the proper relationship of cross-sectional flow areas and flow velocities at various points en route to the slice or nozzle. Also, the process of sizing the nozzle orifice warps at least one of the lips defining the orifice so that the lips are not uniformly separated from each other at all points across the width of the nozzle. In accordance with conventional apparatus and methods, the correction of given fiow aberrations at the slice thus inherently requires the introduction of second order flow aberrations. The given flow aberrations and second order flow aberrations do not cancel each other out, and imperfections in the formed web result.
SUMMARY OF THE INVENTION A principal object of the present invention is to remedy the shortcomings of prior art apparatus and methods noted above. In particular, an object of the invention is to provide a flow system facilitating ejection of stock at high speed from a nozzle in a controlled manner so that the stock remains intact as a wide flat jet a substantial distance beyond the nozzle. Another object of the invention is to facilitate the provision of a uniform stock flow from point to point across the width of the nozzle and from point to point in time. A further object of the invention is to obviate conventional sizing of the nozzle orifice.
These and other objects are attained, in a representative embodiment of the invention, by the combination of an inlet header, a first fiat sectionconnection to the downstream end i of the inlet header and having an unobstructed flow channel generally in the shape of a rectangular parallelepiped, and a plurality of hoses connected in a transverse row to the downstream end of the Hat section. A plurality of expansion pipes is connected in a transverse row respectively to the downstream ends of the hoses, Each expansion pipe has a flow channel of increasing cross section in the direction of stock flow. A plurality of pipes of changing cross section is connected in a transverse row respectively to the downstream ends of the expansion pipes. Each pipe of changing cross section has a circular cross section at its upstream end and a rectangular cross section at its downstream end. A second flat section is connected to the downstream ends of the pipes of changing cross section. The second fiat section has an unobstructed flow channel in the shape of a rectangular parallelepiped. A nozzle is connected to the downstream end of the second flat section.
A representative slice nozzle constructed in accordance with the invention includes first and second lips of great rigidity, each of the lips having a smooth, flat, generally rectangular surface. Means is provided mounting the lips (a) with the surfaces (i) in spaced-apart relation to define therebetween a channel for discharging a jet of paper stock and (ii) in an inclined relation with respect to each other to define a machine direction angle of convergence in the channel. The angle is constant as a function of machine width and has a value within the range of 5 to 10 and preferably about 6.
.The mounting means also mounts the lips (b) adjustably to permit variation of the angle within the given range and (c) only slightly adjustable (because of thepreviously mentioned great rigidity) as a function of machine: width.
In a preferred embodiment of the nozzle, one lip has a first smooth, fiat, generally rectangular surface and the second lip and third smooth, flat, generally rectangular surfaces intersecting each other at an angle. The nozzle lips are mounted so that the first surface on the one hand and the second and third surfaces on the other are in spaced-apart relation to define therebetween a channel for discharging a jet of paper stock. The surfaces are angularly oriented so that the first and third surfaces are generally parallel and the second surface is upstream of the third surface and converges with the first surface in the direction of stock flow.
In both embodiments of the nozzle, conventional sizing of the nozzle orifice by application of varying amounts of force to the lips as a function of machine width is obviated.
BRIEF DESCRIPTION OF THE DRAWING An understanding of additional aspects of the invention can be gained from a consideration of the following detailed description of representative embodiments of apparatus constructed in accordance with the invention, in conjunction with the accompanying drawing, in which:
FIG. 1 is a schematic view in perspective of apparatus constructed in accordance with the invention;
FIG. 2 is a sectional view in side elevation, on a scale larger than that of FIG. 1, showing in greater detail a portion of the apparatus of FIG. 1;
FIG. 3 is a sectional view in side elevation, on a scale larger than that of FIG. 2, of a preferred embodiment of a portion of the apparatus of the invention; and
FIG. 4 is a sectional view in side elevation, on a scale larger than that of FIG. 3, of a portion of the apparatus of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is a schematic view of a flow system 10 constructed in accordance with the invention. A conventional side-entering header 12 may be employed for delivering stock to the flow system 10. The header 12 includes an inlet designated by an arrow 14, a recirculation exit designated by an arrow 16, and a plurality of flow paths designated by arrows 18 through a plurality of tubes 20.
In operation, a flow of stock generated by a pump or other means (not shown) is continuously delivered to the inlet 14. A portion of the stock flows along paths 18 through the tubes 20 and to the flow system 10, and another portion of the stock is recirculated through the exit 16. This portion of the apparatus is conventional per se, and any other suitable means for delivering stock to the fiow system 10 may be employed.
The stock following the paths l8 emanates from the tubes 20 into a flat distribution channel 22 along paths indicated by arrows 24. The distribution channel 22 comprises a lower portion 26 and 28 of the distribution channel 22 provide flat and unobstructed flow channels for the stock.
Stock flows through the upper flat channel 28 in the direction indicated by an arrow 30, and the down stream end 32 of the flat channel 28 is connected to the upstream ends 34 of a plurality of flexible hoses 36. (For the sake of clarity, some of the flexible hoses are omitted from the drawing.)
The downstream ends 38 of the flexible hoses 36 are respectively connected to the upstream ends 4!) of a plurality of expansion pipes 42. The expansion pipes -42 are arranged in a transverse row (with respect to the machine" direction or stock flow direction) corresponding to the transverse row in which the parallel hoses 36 are arranged.
The downstream ends 44 of the expansion pipes 42 are connected to the upstream ends 46 of pipes 48 of changing cross section. The pipes 48 of changing cross section are also disposed in a transverse row and each is connected to a separate pipe 42.. The pipes 48 of changing cross section change gradually along their length from a circular cross section 50 to a rectangular cross section 52.
The downstream ends 54 of the pipes 48 changing cross section are connected to the upstream end 56 of a second flat channel 58. The stock flows through the flexible hoses 36, the expansion pipes 42, the pipes 48 of changing cross section, and the second flat channel 48, in a direction generally indicated by arrows 60 and 62.
The downstream end 64 of the second flat channel 58 is connected to the upstream end 66 of a nozzle 68. A jet 70 of stock issues from the nozzle 68 and is deposited on an endless moving permeable band or between two such bands of the wet end of a paper machine for formation of a web of paper. The wet end of the paper machine (not shown) transports the inchoate web in a direction indicated generally by an arrow 72.
In accordance with the invention, the relationships of the various parts of the flow system to each other are not haphazard but carefully prescribed so that the stock entering the nozzle 68 is characterized by uniform flow across the width of the nozzle and needs only to be accelerated by the nozzle to match the speed of the permeable band or bands on the wet end of the paper machine and, in effect "focused" to maintain its integrity a substantial distance beyond the slice. The importance of maintaining the integrity (i.e., preventing breakup) of the ejected stock is especially great at high forming speeds and under circumstances when because of the construction of the nozzle or of the wet end of the paper machine it is necessary to fly" the stock to a desired point of impact on the permeable band or bands.
For every assumed flow rate at the slice, there are corresponding flow velocities at various points along the flow system 10. If it is assumed that the stock flow rate at the nozzle 68 is established at a value within the range of 36 gallons of stock per minute per inch of machine width to 40 gallons of stock per minute per inch of machine width, then the speed of stock flow through the distributor tubes 20, which typically have an internal diameter of three-fourths of and inch, assumes a value between about 15.77 feet per second and about 17.52 feet per second in the apparatus illustrated.
The depth of the lower portion 26 of the distribution channel 22 in a direction normal to the plane defined by the direction of the arrow 30 and the cross machine. direction is preferably about 3 inches, so that, for the assumed range of flow rates, the flow speed of the stock in the lower portion 26 of the channel 22 is within the range of about 3.87 feet per second to about 4.30 feet per second.
The depth of the upper portion 28 of the channel 22 is preferably about 1% inches, and the stock flow speed through this portion of the channel assumes a value between about 7.74 feet per second (in the case where stock flow rate is 36 gallons per minute per inch of machine width) and about 8.60 feet per second (in the case where stock flow rate is 40 gallons per minute per inch of machine width).
Each flexible hose 36 preferably has an internal diameter of about 1% inches, and the center-to-center separation of the hoses 36 is about 3 inches. Each hose should be of an appropriate length, typically 90 inches to 110 inches long, or about twice the flow direction length of the upper portion 28 of the channel 22. The upper portion 28 may have a flow direction length of 54 inches, for example.
The expansion pipes 42 have an internal diameter of 1% inches at their upstream ends 40 and expand as cones on an internal diameter of 2 inches at their downstream ends 44. They are preferably about 24 inches in length, so that the angle of expansion does not exceed 6.
For the flow rates assumed above, the flow speed decreases from the range of about 19.71 feet per second (in the case of the flow rate of 36 gallons per minute per inch of machine width) to about 21.91 feet per second (in the case of a flow rate of 40 gallons per minute per inch or machine width) in the flexible hoses 36 and the upstream ends 40 of the expansion pipes 42 to a range of about 11.09 feet per second to about 12.32 feet per second (depending, of course, on the flow rate) at the downstream ends 44 of the expansion pipes 42.
Like the expansion pipes 42, the pipes 48 of changing cross section are preferably about 24 inches long, but, unlike the pipes 42, the pipes 48 of changing cross section do not provide an increasing cross-sectional flow area for stock traveling therethrough. On the contrary, the cross-sectional flow area of the downstream ends 54 of the pipes 48 of changing cross section is slightly less than the cross-sectional flow area at the upstream ends 46, so that stock passing through the rectangular openings 52 and flowing through the second flat channel 58 moves at about 11.61 feet per second to about 12.91 per second, depending upon the flow rate.
The flow direction length of the second flat channel 58 may range up to about 42 inches, and stock passing therethrough enters the nozzle 68 of the invention, important characteristics of a first embodiment of which are shown in FIG. 2.
As FIG. 2 clearly illustrates, the nozzle 68 is significantly different from conventional nozzles having highly flexible lips. The nozzle 68 includes first and second lips and 82 of great rigidity. The lips are formed with smooth flat, generally rectangular surfaces 84 and 86, respectively, and the lips are mounted by means indicated generally at 88 with the surfaces 84 and 86 in spaced-apart relation to define therebetween a channel 90 for receiving and discharging a jet of paper stock.
The surface 84 and 86 are inclined with respect to each other to define a machine direction angle of convergence in the channel 90. The angle of convergence is constant as a function of machine width: i.e., the angle is the same at all points across the width of the nozzle 68. The angle of convergence between the surfaces 84 and 86 in the direction of stock flow through the channel 90 is within the range of 5 to 10 and preferably about 6.
7 1n the embodiment illustrated in FIG. 2, the surface 84 lies in the plane of a surface 92 defining the lower boundary of the flow channel within the second flat section 58. The surface 92 is the upper surface of a platelike member 94 formed with a flange 96 at the down stream end thereof. A heavy beam 98 is secured by a plurality of bolts such as a bolt 100 to the flange 96. The bolt 100 is passed slidably through an aperture 102 in the beam 98 and screwed into a threaded bore 104 formed in the flange 96.
The beam 98 supports the lower lip 80, to which it is securely attached by a plurality of bolts such as a bolt 106. The bolt 106 is passed slidably through an aperture 108 formed in the beam 98 and screwed into a threaded bore 110 formed in the lower lip 80. Access to the heads 1 12 and 114, respectively, of the bolts 100 and 106 is provided by a generally prismatic recess 116 formed in the beam 98.
The upper lip 82 is integral with one or more generally cylindrical members 118 facilitating pivotal mounting of the lip 82. The member 118 is secured by a retaining block 120 formed with a downwardly projecting protuberance or flange 122. A plate like member 124 similar in construction to the platelike member 94 and the surface 126 of which is parallel to and spaced apart from the surface 92 is formed with an upwardly projecting flange 128. At the junction of the member 124 and flange 128, a protuberance 130 is formed having a concave surface 132 complemental to the outer surface 134 of the member 1 18. The block 120 is also formed with a concave surface 136 extending upwardly and rearwardly (as compared to the direction of stock flow) from the protuberance 122. The concave surfaces 132 and 136 define a housing within which the member 118 is held securely but rotatably. The block 120 is secured to the flange 128 by a screw or bolt 138 passed slidably through an aperture 140 in the block 120 and screwed into a threaded aperture 142 in the flange 128. The
screw or bolt 138 is provided with a head 144 slotted at 146 andreceived in a counterbore 148 formed in the block 120. The slot 146 facilitates the screwing and unscrewing of the bolt or screw 138.
An adjustment screw 150 and upper and lower adjuster nuts 153 and 154, respectively, facilitate pivotal adjustment of the upper lip 02. The adjustment screw 150 fits loosely within an aperture 152 formed in a rigid beam 155 extending the width of the nozzle 68. The position of the adjustment screw can be adjusted upwardly and downwardly by appropriate adjustment of the adjuster nuts 153 and 154, as those skilled in the art will understand. Movement upwardly and downwardly of the adjustment screw 150 causes movement upwardly or downwardly, as the case may be, of the left-hand end (as viewed in FIG. 2) of the upper nozzle lip 32. Specifically, the adjustment screw 150 is connected to the upper lip 102 by an anchor pin 160 extending through an aperture 162 formed in the adjustment screw 150. The anchor pin 160 passes through apertures 164 and 166 formed in lugs 168 and 169, respectively. The lugs 168 and 169 are in turn integral with the upper lip 82. The aperture 162 is large enough with respect to the diameter of the anchor pin 160 to permit slight play of the anchor pin during pivotal adjustment ofthe upper lip 102.
The beam 155 is secured to the flange 120 by a bolt 170 passed slidably through an aperture 172 in the beam 155 and screwed into an aperture 174 in the flange 120. A recess 176 facilitates access to the adjuster nut 153 and the head 170 of the bolt 170.
In the embodiment illustrated in FIG. 2, only the upper nozzle lip 82 is pivotally adjustable, the lower nozzle lip being unadjustably secured with the surface 84 in the plane of the surface 92. The plane of the surface 06 intersects the plane of the surface 126 at an angle variable within small limits on either side of 6 For example, the angle may be as little as or as much as l0".
In certain embodiments (not shown), both the upper lip 02 and the lower lip 80 are pivotally mounted, and their planes intersect at an angle bisected by a plane parallel to the planes of the surfaces 92 and 126. That is, the plane of the surface 84 is rotated through an angle of, say, 3 clockwise (as seen in FIG. 2) with respect to the planes of the surfaces 92 and 126, and the surface 86 is rotated through an equal angle counterclockwise with respect to the planes of the surfaces 92 and 126 (or clockwise with respect to the plane of the surface 06 represented in FIG. 2).
As noted above, the depth of the channel 50 (i.e., the space between the surfaces 92 and 126) is preferably I inch. The separation of the outer extremities 100 and 182 of the nozzle lips 80 and 82, respectively is then about one-fourth of an inch, or, more precisely, within the range of about 0.220 inch to about 0.280 inch. Thus, there is a reduction in cross-sectional flow area of about 4 to I along the flow direction length (which may be of the order of 6 inches) of the nozzle and a corresponding acceleration of the stock by a factor of about four or so that the stock ejected from the nozzle is moving at the desired speed (the speed of the paper-forming element or elements on the wet end of the paper machine). Slight pivotal adjustment of the type referred to above facilitates matching the speed of the ejected stock to the speed of the endless forming band on the wet end of the paper machine without changing the pumping capacity of the pumps, which may be adjusted to pump stock at an optimum rate, say within the range of 36 gallons per minute to 40 gallons per minute per inch of machine width, regardless, within limits, or the speed at which it is desired to run the wet end of the paper machine.
FIGS. 3 and 4 show in detail a preferred embodiment of the nozzle 68 in which the lower lip 198 has not merely one but two smooth, fiat, generally rectangular surfaces 200 and 202, respectively, which, with the smooth, flat, generally rectangular surface 204 of the upper lip 206 define the channel 90. The surfaces 200 and 202 intersect at a line 208 extending across the nozzle 68 transversely of the direction of stock flow from one side of the nozzle to the other.
The nozzle 60' is connected to a flat channel 50. Stock flows between surfaces 210 and 212 of platelike members 214 and 216, respectively. The surfaces 210 and 212 are spaced apart from each other by about an inch. A pipe 40 of changing cross section is shown connected to the flat channel 50' by bolts 210 passed slidably apertures 220 in lugs 222 and screwed into threaded apertures 224 formed in the platelilte members 214 and 216.
The lower lip 190 abuts the platelike member 214 at a line 226 extending transversely of the direction of stock flow and tapers upwardly and to the left (as seen in FIG. 3) from the line 226 to the line 200. The machine direction length of the lip 198 is preferably about 6 inches, and the machine direction length of the flat" 202 is within the range of one-fourth of an inch to one-half an inch. A length of nine-thirtieths of an inch has given excellent results.
The sloping surface 200 thus preferably has a machine direction length of 5 /2 inches to 5% inches, and the slope is such that the elevation of the flat 202 as compared to the surface 210 (the surfaces 200 and 210 being substantially parallel) is about 0.625 inch. Thus, the acute dihedral angle between the plane of the sloping surface 200 and the plane of the surface 210 or 212 is within the range of arc tan 0.625/5.75 and are tan 0.625/5.5, or somewhat more than 6.
The angular orientation of the surface 204 of the upper lip 206 is adjustable so that the separation between the flat 202 and the surface 204 ranges from a minimum of 0.220 inch to a maximum of 0.375 inch. When the adjustment of the lip 206 is such that the surface 204 is at an elevation (with respect to the flat 202) of 0.375 inch, it is at an elevation of 0.625 inch plus 0.375 inch or 1 inch with respect to the surface 210 and is parallel to that surface and in the plane of the surface 212. When the adjustment of the lip 206 is such that the minimum separation of 0.220 inch exists between that surface and the flat 202, the acute dihedral angle between the plane of the surface 204 and the plane of the surface 210 or 212 is are tan 0.155/13, or less than l. This follows from the fact that the difference between the maximum spacing between the surface 204 and the flat 202 and the minimum spacing between those surfaces is 0.155 inch, while the machine direction length of the upper nozzle lip 206 is chosen to be about 13 inches.
The acute dihedral angle formed by the plane of the surface 200 and the plane of the surface 204 is equal to the sum of the acute dihedral angle formed by the plane of the surface 200 and the plane of the surface 210 or 212 and the acute dihedral angle formed by the plane of the surface 204 and the plane of the surface 210 or 212 FIG. 4 shows an adjustment of the upper lip 206 so that the minimum spacing between the surface 204 and the flat surface 202 is 0.250 inch.
The lips 190 and 206 are retained in their desired positions by suitable mounting means. Thus, the lip 190 is secured by a screw 230 passed slidably through an aperture 232 formed in a mounting block 234 and screwed into a threaded aperture 236. The aperture 236 is spaced apart from the end 230 of the lip 190 a distance equal to the distance by which the aperture 232 is spaced apart from a shoulder 240 formed on the mounting block 234. The end of 230 of the lip 190 thus abuts the shoulder 240 when the screw 230 fastens the lip 190 to the mounting block 234.
The machine direction length of the mounting block 234 from the shoulder 240 to the upstream end 242 thereof is equal to the depth of a recess 244 formed in a massive end portion 246 integral with the platelike member 214. A bolt 240 is passed slidably through an aperture 250 formed in a retaining member 252 and screwed into a threaded aperture 254 formed in the portion 246. A hexagonal head 256 facilitates tightening of the bolt 240.
A shoulder 250 is formed on the mounting block 234 on the side thereof opposite the shoulder 240. The shoulder 250 is adapted to engage a complemental shoulder 260 formed on the retaining member 252.
The bolt 248 thus urges the shoulder 260 of the retaining member 252 firmly into engagement with the shoulder 258 of the mounting block 234, and the mounting block 224 in turn holds the lip 198 so that the end 238 thereof firmly abuts the portion 246 and no leakage of stock occurs at the transverse line 226.
The upper lip 206 is integral at its upstream end 264 with a generally cylindrical member 266. The cylindrical member 266 is retained by a protuberance 268 formed on a retaining member 270. The surface 272 of the retaining member 270 tapers upwardly and rearwardly (with respect to the direction of stock flow) from the protuberance 268 to its intersection with the downstream surface 274 of a flange 276 integral with the platelike member 216.
The surface 274 extends downwardly and forwardly (with respect to the direction of stock flow) from its intersection with the surface 272, so that the surfaces 272 and 274 form a housing for the cylindrical member 266.
The retaining member 270 is secured to the flange 276 by bolts 278 passed slidably through apertures 280 formed in the retaining member 270 and threaded into apertures 282 formed in the flange 276.
The downstream end of the retaining member 270 is formed with an aperture 286 through which is slidably passed an adjustment screw 288. The elevation of the adjustment screw is adjustable by adjuster nuts 290 and 292. An anchor pin 294 extends through an aperture 296 in the adjustment screw 288 and through an aperture (not shown) in a lug 298. The anchor pin 294 is screwed into a threaded aperture 300 formed in a lug 302. The lugs 298 and 302 are integral with a block 304 which is in turn integral with the upper lip 206.
By adjustment of the adjuster nuts 290 and 292, the upper lip 206 can be pivoted about the cylindrical member 266 to adjust the angular orientation of the lip 206.
Those skilled in the art will of course understand that a number of mounting means such as the cylindrical member 266 and'the various bolts described above may be used across thewidth of the machine in order to provide a secure mounting for the lips 198 and 206. In all cases, however, the rigidity of the lips is substantially limited to adjustment of their angle of convergence; substantially no warping of the lips across the width thereof.
The flat surface 202 shown in F IG. 4 has been found to contribute significantly to maintenance of the integrity of the jet beyond the nozzle lips. The pressure drop in the stock at the nozzle occurs substantially entirely in the portion of the nozzle upstream of that surface 202. The pressure drop accompanied by an acceleration occurring in the portion of the nozzle 68' upstream of the flat surface 202 is followed by the portion of the nozzle 68' adjacent to the flat surface 202, the latter portion acting as a guide to the flow of stock. This structure facilitates the preservation of the integrity of the jet of stock a maximum distance beyond the nozzle 68 An important advantage of the structure is that it permits the introduction of an integral jet of stock between a pair of forming wires on a paper machine wet end at a location considerably removed from the nozzle. This permits the use of breast rolls having the desired diameters in large paper machines.
The surfaces 84 and 86 of the nozzle 68 and the surfaces 200, 202 and 204 of the nozzle 68' should be accurately machined to within one one-thousandth of an inch within any span of 16 inches. This means that, when the lips are mounted without warping in the flow system, the separation between the opposed surfaces of the lips defining the flow channel in a direction transverse of the direction of stock flow is constant to within two one-thousandths of an inch in any span of 16 inches. This is true not only at the downstream end of the nozzle lips but also at other positions thereof. Thus, the warping adjustment of the upper nozzle lip (or whichever nozzle lip is adapted to be adjusted) need never exceed two onethousandths of an inch in any span of 16 inches. Accurate adjustment within but not exceeding this limit is facilitated by at the provision of nozzle lips that are substantially rigid.
The adjustable nozzle lip is preferably the one the channeldefining surface of which lies in the plane or nearly in the plane of one of the channel-defining surfaces of the flat section. FIG. 3 illustrates this principle. This arrangement assures that the surface 200, which converges more sharply with the direction of stock flow than does the surface 204, need never be adjusted. Such adjustment as may be necessary therefore causes a minimum disruption of the ejected jet.
In operation, the flow system of the invention is adapted to produce a flow of stock from which it is possible to make paper, including paper of the highest quality, rapidly and economically. The flow system is particularly adapted for use in combination with modern paper machines of the type disclosed in an application of John A. Means, Ser. No. 407,307, filed Oct. 29, l964, now US. Pat. No. 3,438,854 for l aper Manufacture." Stock emanating from the tubes 20 is abruptly decelerated upon entering the lower portion 26 of the first flat section or channel 22 and then accelerated in the upper portion 28. The stock is then further accelerated when it enters the flexible hoses 36 and is simultaneously divided from flow in a single wide sheet to flow in a plurality of flow paths. Then the stock is decelerated as it enters the expansion pipes 42 and accelerated slightly in the pipes 48 of changing cross section. Simultaneously, flow along the separate flow paths changes from circular in cross section to rectangular in cross section in order to facilitate the reuniting in the second flat section or flat channel 58 of the flow in a single wide flat stream. Then, in the nozzle 68 or 68', the stock is greatly accelerated and ejected at forming speed.
The alternation of acceleration and deceleration and of flow in a single wide flat channel and flow in a plurality of separate paths described above prevents flocculation and slime growth and maintains the stock in a turbulent homogeneous condition. The stock is then ejected from the nozzle in a controlled manner so that the stock remains intact as a wide flat jet a substantial distance beyond the nozzle.
The requisite rigidity is imparted to the nozzle lips and 82'by making them very thick and of a strong material: typically, they may be as much as 2 inches thick and formed of stainless steel. Thus, adjustment of the adjustment screw and adjuster nuts 153 and 154 shown in FIG. 2 and of-the corresponding structure shown in H6. 2 and of the corresponding structure shown in FIG. 3 does not warp the upper lip 82 or 206 to the point of causing deterioration of the quality of the ejected stock, even though a plurality of such adjustment means may be provided across the width of the lip. Sizing of the nozzle orifice is therefore greatly simplified, being largely a matter of matching stock speed to wire speed, and the results in terms of the quality of the finished product are superior to the results achieved in conventional flow systems because the separation between the outer edges of the lips is uniform across the width of the nozzle to a degree unrealized heretofore.
The cooperation between the channel 58 and the nozzle 68 or 68' is particularly noteworthy. The channel 58 establishes the proper velocity for a papermaking slurry. This controlled velocity is sufficient to prevent flocculation of fibers and at the same time keeps the level of turbulence low enough to prevent eddies from extending into the forming or dewatering zone of the wet end of the paper machine. Excessive turbulence results in thin, weak areas in the resulting paper web. The convergence, preferably about 6, effected by the nozzle 68 or 68' at the end of the channel 58 imparts a direction to the ejected stock somewhat different from the planes of the surface 84 and 86 or 200, 202, and 204. That is, the flow lines of the ejected stock change direction because of the design of the nozzle in such a way as to maintain the ejected stock intact. lt has been found possible to fly the stock of distance of 9 to 12 inches between permeable forming bands without degrading the quality of the completed paper.
The cooperation of the flexible hoses 36 in the combination is also of particular importance. In the lengths prescribed, the hoses prevent fiber flocculation and break up entering flocks to establish fiber-to-water consistency ratios and flow rates best suited for the wet end of the paper machine.
Thus, there is provided in accordance with the invention novel and highly effective apparatus and methods facilitating the delivery to a paper machine wet end of paper stock facilitating high-speed and economical manufacture of paper of the highest quality. Many modifications of the disclosure made herein will occur to those skilled in the art. For example, a cross-machine distribution device having a tapered, lowvelocity inlet section and a perforated plate can be substituted for the header 12. Also, a ball-in-socket connection can be used in place of the pins 160 and 294 and associated structure shown in FIGS. 2 and 3. Again, while a generally horizontal orientation has been illustrated for the flow system 10, other orientations are possible. Accordingly, the invention is to be construed as extending to all of the embodiments thereof within the scope of the appended claims.
1. In a slice nozzle for ejecting a jet of paper stock onto the wet end of a paper machine, the combination of first and second lips and means mounting said lips with a surface of each in nonparallel spaced-apart relation to a surface of the other to define therebetween a converging channel for discharging a jet of paper stock, said surfaces being inclined with respect to each other to define a machine direction angle of convergence in said channel, said angle being constant as a function of machine width and having a value within the range of 5 to 10, said mounting means being adjustable to permit variation of said angle within said range, each of said surfaces being smooth, flat and generally rectangular further comprising a flat channel upstream of said converging channel, formed between two parallel surfaces, said parallel surfaces forming an angle with at least one of said nonparallel surfaces.
2. A nozzle is set forth in claim 1 in which said angle is about 6.
3. In a slice nozzle for ejecting a jet of paper stock onto the wet end of a paper machine, the combination of first and second lips said first lip having a first smooth, flat, generally rectangular surface devoid of projections and said second lip having a second smooth, flat, generally rectangular surface devoid of projections and a third smooth, fiat, said second and third surfaces intersecting each other at an angle, and means mounting said lips with said first surface on the one hand and said second and third surfaces on the other (i) in spaced-apart relation to define therebetween a channel for discharging a jet of paper stock and (ii) oriented so that said first and third surfaces are generally parallel to each other and to the direction of stock flow and said second surface is upstream of said third surface and is nonparallel to and converges with said first surface in the direction of stock flow.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3220919 *||Oct 5, 1962||Nov 30, 1965||Beloit Corp||Shaped rod turbulence generators for use in a flowing stream of paper pulp|
|US3309264 *||Jan 17, 1964||Mar 14, 1967||Beloit Corp||Flow distributor for a papermaking machine|
|US3328236 *||Jun 22, 1964||Jun 27, 1967||Black Clawson Co||Bunched tube approach to a headbox of a papermaking machine|
|US3345254 *||Jun 24, 1964||Oct 3, 1967||Black Clawson Co||Multiple manifold headbox|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3902961 *||Oct 19, 1973||Sep 2, 1975||Beloit Corp||Adjustable slice lip for a headbox|
|US3963562 *||Jan 14, 1974||Jun 15, 1976||Lodding Engineering Corporation||Slurry distributor|
|US4021296 *||Nov 7, 1974||May 3, 1977||A. Ahlstrom Osakeyhtio||Method and device for manufacturing a continuous material web of elongated fibrous particles|
|US4517055 *||Jun 6, 1983||May 14, 1985||Dove Norman F||Slice lip control|
|US4783241 *||Dec 17, 1987||Nov 8, 1988||J. M. Voith Gmch||Head box for a paper machine|
|U.S. Classification||162/336, 162/343, 162/347|
|International Classification||D21F1/02, D21F1/00|
|Cooperative Classification||D21F1/02, D21F1/028|
|European Classification||D21F1/02G, D21F1/02|