Патент USA US2130665код для вставки
Sept. 2o, y1938. ` D.' B. BRADNER METHOD 0F AND M ACEINE 2,130,665 FOR DRYING OR CONDITIONI NG' WEBS OF PAPER AND THE LIKE Flled Sept 18 1935 2 sheets-sheet 1 Sept. 20, 1938. D_ B_ BRADNER 2,130,665 METHOD OF AND MACHINE FOR DRYING OR CONDITIONING WEBS OF PAPER AND THE LIKE Filed Sept 73 E 77 nu -/ 2 Sheets-Sheet 2 70 / _I 77 #gl 9 18, 1935 777 Í `l ¿3 26.70 39 W 2,5 ‘9 `Z6 Z6 »CH 52:2 @E KFM Patented Sept. 2,130,665 1938 UNITED STATES PATENT OFFICE 2,130,665 METHOD OF AND MACHINE FOR DRYING OR CONDITIONING WEBS 0F PAPER AND THE LIKE Donald B. Brenner, Hamilton, ohio, assigner to The Champion Paper and Fibre Company, Hamilton, Ohio, a corporation of Ohio . Application September 18, 1935, S‘erial No. 41,171 14 Claims'. 'I'his invention relates to methods of and ma chines for drying or conditioning webs of paper and the like; and it comprises a supporting de vice such as a foraminous wire belt adapted to 5 supporta moving web of paper, ablower, a duct connected to the discharge of the blower, said duct advantageously having converging walls, and _adapted to discharge air into a diverging passageway formed by said supporting device and 10 by an impervious member adjacent thereto; and it further comprises a method of conditioning more or less diagrammatically, an example of a specific embodiment of the invention.. In the drawings, . l Fig. 1 is a perspective view, partly in section, of the drying machine, showing the air passage arrangement; „ Fig. 2 is a plan view corresponding to Fig. 1 and showing the carrier for the web; and ' Fig. 3 isan end view of the apparatus of Fig. 1 illustrating the air passage system. In the showings, in which like reference char 10 webs, including supporting the web on one side acters indicate >like parts throughout, the ma- on ‘a foraminous carrier and blowing air at high _chine is shown as having an endless foraminous velocity over the other side of the carrier and carrier I0 adapted to support a web 9 and carried 15 adjacent the supported side of the web, while on two large drums Il (Fig. 2) only one of which 15 is shown in Fig, 1. Driving means are shown for maintaining the static pressure of the high ve locity air adjacent the web substantially uniform „one drum,'comprising a pulley I2 and belt I3 and slightly subatmospheric; all as morefully driven by power means, not shown. Aswill be hereinafter set forth and as claimed. 20 , The invention is particularly adapted to >the drying of paper after it has been coated, gummed or the like. It eliminates the necessity of cum bersome festoons with their attendant dimculties, and provides apparatus for drying or otherwise 25 conditioning webs rapidly, continuously and without injury. The webis held flat during the drying operation. -According to the invention explained, the omitted. The wire mesh, the eliminates the _driving means are in some cases carrier is advantageously of wide 20 wires being wavy, as shown, which possibility of occurrence `of dead spots during drying. The apparatus is provided with supporting columns 50 carrying cross beams 5l on which are supported siderails i9. The carrier is movably supported on a plurality of v25 spa-ced roilers I8 mounted in bearings 52 4on the there is provided a machine having a pervious ` side rails. Below the carrier are positioned a plurality of air circulating units. Each unit comprises a 30 double blower it driven by a belt I5v from a power flow and reduced pressure whereby the web> is » shaft i6„ driven by a motor Il as shown. The lightly but ñrmly drawn against the support and two outlet conduits 20 of the double blower are air is passed rapidly> across the entire width of - merged as Yat 2| into a passage of curving shape 22. The top of this passage merges into two 35 35 the web. ‘ The uncoated or dry side of the paper support for a moving web and an arrangement of 80 air passages for blowing hot air over the support ed surface of the paper under conditions of rapid is in contact with the support. In the apparatus air is‘forced by a blower through a progressively constrlcted channel and delivered to the paper in a gradually diverging passageway.. the system 40 Vconstituting in essence, an embodiment of a Venturi tube. ` Air at relatively ylow velocity and relatively high static pressure thereby assumes a condition of relatively high velocity and low static pressure, and in the latter conditionr it impinges ß'ßupon the web. It is arranged that the static pressure of this high velocity‘air shall beapproxi mately\uniformly less than atmospheric (or less ‘ plates or sheets 23 closely spaced from the carrier It. The inner portions of the sheets 23 are sup ported on longitudinally extending girders 26. The sheets 23 extend outwardly to the edges of the carrier and are slightly deiiected downward, thus providing two narrow passageways. 25 be tween the plates and the lcarrier `whichy passage ways progressively -increase `slightly in cross vsec tional‘area toward the edges of the carrier. The amount and rate of this increase in` the cross sectional area of passageways 25 is important` for reasons’ >hereinafter pointed out. A restricted than 'that on the opposite side of 'the‘web)` across ' throat portion 24 joins these passageways 25 with -the entire surface 'of"the,web, thusholding the the duct 22 from the blower. This throat por oo‘web flat _against 1 the `supporting screen. Under" tion is the vmost constricted'passage in the system. 50 ' . thesey conditions diffusion of water or other sol- ‘ vent from'the opposite, freshly _coated side of the web is very fast -and there results a very rapid rateof'dryingm` _ « ' ' Y ` 56 \ vIn the accompanying drawings there is shown, The'air passage arrangement described isin effect ‘a venturi. Air is delivered by the blower ` into " conduit 2| Aat a given gage pressure and a given velocity.-` In going through the throat por, tion‘ 24 the velocity ‘increases and the static head 2 2,130,665 falls.I The air then enters passageways 25 which, as héreinbe‘fore pointed out, gradually increase in cross sectional area. The' dimensions of the passageways and the rate of increase of their cross sectional area are such that the air here is in a condition of high velocity and approximately uniformly reducedpressure across the whole web area. With a suitable blower the pressure is slightly subatmospheric.` In practice the‘gage 10 pressure is of the order of magnitude of an inch of water (.04 pound per square inch) below atmospheric. This is suiiicientto draw the web down flat upon the carrier, where it is rapidly dried by the high velocity hot air blast. 15 Return air ducts 30 are provided to deliver the air back to the heater 33 and thence to the blower intake. Not all of the air is ordinarily recirculated. Gaps 34 are provided on each side of the apparatus between the carrier i0 and side 20 walls 43. These allow some leakage of air in and out of the system. If desired all the air may be exhausted to .the atmosphere but to economize heat it is advantageous to recirculate a consid erable portion. 25 'I‘he sides of the machine are provided with impervious heat insulated walls 43. Figs. 1 and 3 show an air control arrangement which I have found useful in connection with this machine. As shown, the restricted throat 30 -portion 24 is provided with an inner pair of curved deflecting plates 39, forming two. channels 40 dividing the air stream and directing it into passages 25. The two deflectors also form be tween them an air passage 4I delivering to the A longitudinally 35 center axial region of the web. extending damper 42 is provided by which means Ait is possible to direct air to the center portion of the. web in the required proportion, „to secure e .n drying. . . 'I'he character of the moving carrier is im portant. It is desirable that there should be relative movement between the carrier and the moving web. Sometimes it suilices to keep the ca1--er stationary and simply movethe web with chine as it is found that _the web is held ñat against the carrier and is restrained from tend encies to curl. In operation the drying of the web is exceptionally rapid. 'I'he following example illustrates, by way of 5 example, a typical paper drying operation utiliz ing the present machine. ~ Paper stock 39 inches wide and of a grade commonly used for making coated paper, weigh ing 50 pounds per ream (500 sheets-25 x 38 10 inches) was coated with a typical clay-water casein coating composition containing 25 pounds of water per ream of coated paper. The coated paper was continuously delivered to one end of the carrier, which was moved at a speed slightly 15 less than that of the web. Hot air was delivered to the under side of the paper by the blowers at a velocity of 175 feet per second. The static pressure below the web was 3A inch of water be low atmospheric and the temperature of the hot 20 air blast was 275° F. The paper was completely dried in 10 seconds.. After leaving the other end of the carrier it was wound on a reel (not shown). In case even more rapid drying is desired, the top face of the web may be subjected to a warm 25 air current. But for manypaper coating opera tions, I iind that the operation described, ab stracting water-from the lower surface alone, gives a superior product.. The drying is sufii ciently rapid for all ordinary purposes. The ap--_ paratus is well suited for drying uncoated paper. The apparatus is well adapted for drying other webs than paper; cloth for example. It can also be used for other web conditioning operations. What I claim isz 1. Machine for conditioning webs, comprising a conduit having walls converging to a narrow throat, a foraminous carrier for a web, a partl tion member adjacent said carrier and slightly inclined with respect thereto, a passageway com municating with the throat and deñned on oppo site sides by said carrier and said partition mem ber, said passageway thus gradually increasing in cross sectional area in a direction away from the 45 respect to it. That is, the apparatus may be provided with a stationary foraminous top. Usually I find it better to drive the carrier in the throat, and means for delivering air through said conduit and throat into said passageway. 2. Machine for conditioning webs comprising a same direction as the paper but at a slightly> foraminous carrier for a web, a conduit having different speed, which may be either faster or walls converging to form a narrow throat, an 50 slower than the paper. The object securedxin extension of said walls disposed slightly inclined each case is to insure movement of the paper with respect to the web carrier and deñning an 50 relative to the carrier so that all portions of the air passage formed on the one side by the carrier under surface of the'paper are exposed to the member and on the other by the extension of air current. Otherwise imperfect drying and , the walls of the throat portion, said air passage The word “carrier” gradually increasing in cross sectional area to l as used in the specification and claims refers to provide approximately uniformly lowerpressure 55.y this supporting member regardless of whether it on- the one side of the carrier than on the other, is stationary or driven as described. The carrier and a. blower adapted to discharge into said 55 other defects might result. is conveniently made of woven wire of very open 60 mesh. I have found that a screen composed of wire strands 0.08 inch in diameter with meshes 1- x 2 inches is satisfactory. The carrier can be made of thin perforated metal or of cloth, if desired. It is desirable that the longitudinal -65 Wires of the screen be curved or staggered, as indicated in Fig. 2, so as to prevent any portion of the paper from Ibeing continuously in contact lwith the carrier througout the entire drying operation. 70 Observations on the behavior of the machine in operation indicate that in the immediate vi cinity of ,an individual carrier wire the pressure is appreciably greater than that between the wires. These local pressure variations do not 75 interfere with'the proper functioning of the ma conduit. « . 3. Machine for conditioning webs comprising a 60 blower, a foraminous carrier for a web and means for delivering air over a substantial area of that surface of the web supported by said carrier at high velocity and at a pressure substantially uni formly less than that on the opposite side of the web, said means comprising a conduit of pro gressively decreasing cross sectional area leading from'the blower, a partition member adjacent the carrier and forming in conjunction therewith an air passage into which air may-be delivered 70. through said conduit, said air passage increasing gradually in cross sectional area in the direction -of the passage of air therethrough. 4. Machine for conditioning webs comprising a foraminous carrier for` a web, a blower, an air 2,130,665 3 prises supporting the web on one~ side of a forami nous carrier and passing air at high velocity over the other side of the carrier while maintaining ally decreasing in cross sectional area from the lthe static pressure of the high velocity air adja cent thexcarrier substantially uniform and slightly blower to said carrier and then ‘gradually in creasing in cross sectional area throughout the subatmospheric. ` duct leading from said blower to said carrier and returning to said blower, said carrier forming a part of one wall of said duct, said air duct gradu-h part of its length bordered by said carrier. 5. Machine for drying web material comprising 10. Method of conditioning webs which com prises passing air at high velocity over one side of the web, supporting this side of the web on a foraminous carrier and holding the web against 10 for heating air, a conduit gradually converging 10 the carrier by maintaining the static pressure to a constricted throat, means for forcing heated a foraminous carrier for supporting a web, means ' air through said conduit and throat, a partition member connecting with a wall of the throat, and forming in conjunction with the carrier a 15 gradually enlarging passageway adjacent the carrier to carry air at high velocity and sub atmospheric pressure along the side of the web in contact with the carrier, return ducts con necting said passageway with said air forcing 20 means and bleed means putting the system in communication with the atmosphere.` A 6.“ Machine for conditioning a web comprising a foraminous supporting device adapted to sup port a moving web, a blower, conduit means 25 leading from the blower to a zone adjacent the central portion of the web so as to discharge air to the supported side of the web in a narrow path between the two edges thereof substantially centrally of the web as the web travels over the 30 supporting device, partition _members closely ad jacent the supporting device and forming in con junction therewith gradually enlarging passage ways adjacent the supporting device through 35 which the air flows at high velocity and at sub stantially uniformly lower pressure than that exi'ting on the unsupported side of the web and means near the edges of the web for removing air from the vicinity of the web. - 7. Machine for conditioning a web comprising a foraminous supporting device adapted to sup port a moving web, a blower, a conduit connected to the blower and tapering to form a narrow throat portion substantially centrally of the web, sheet members spaced from the supporting de vice, the distance between the sheet members and 45 the supporting device gradually increasing to wards the edges of said device, and means in thethroat portion to deñect air along the sup ported side of the web to each edge thereof through passageways bounded by the supporting 50 device and by said sheetV members. 8. The apparatus of claim 3 wherein the fo f raminous carrier for theI web is an endless wire screen belt and means are'provided for moving the carrier and for moving the web at diñerent 55 relative speeds. 9. Method of conditioning webs which com of the high velocity air adjacent thereto sub stantially uniformly just below the pressure on the opposite side of the web. 11. Method of conditioning webs, which com is> lprises imparting velocity to a stream of air; passing the stream through a contracting pas sageway to increase its velocity and decrease its static pressure; then causing it to iiow, at high velocity and low static -pressure, in contact with 20 and substantially parallel to the surface of the web, maintaining its static pressure substantially uniform', by causing it to pass through a gradu ally enlarging passage, while it is in contact with the web, and supporting the web on the side exposed to the stream of air. 12. Machine for conditioning webs, comprising a conduit having lwalls converging to a narrow throat, a foraminous carrier for a web, partition members adjacent said carrier and slightly in 30 clined with respect thereto, two passageways having a common inlet `communicating with the throat, said passageways being defined on oppo site sides by said carrier and said partition mem bers, and thus increasing gradually in cross sec 25 tional area in a direction away from the throat, and means for delivering air through said con duit and throat into both of said passageways. 13. A machine for conditioning web material comprising a blower, a foraminous supporting device adapted to support a moving web, a con stricted throat near the central portion of said supporting device, a conduit leading from the discharge side of the blower to said throat, sheet members near said supporting device and slightly 45 inclined thereto, said sheet members and sup porting device defining passageways which lead from `said throat to the edges of said supporting device and gradually increase in cross sectional area away from said throat, and means for con ducting air to the central portion of said sup porting device between said passageways. 14„The machine of claim 13 in which means are provided for regulating the amount of air conducted to the central portion of the supporting device. DONALD B. BRADNER.