USRE22593E

USRE22593E - Finishing and conditioning of paper

Info

Publication number: USRE22593E
Authority: US
Publication date: 1945-01-23

Description

Jan. 23. 1945. A. E. MONTGOMERY R-' FINISHING AND CONDITiONING OF PAPER Original Filed May 27. 1 938 INVENT OR.

ATTORNEYS MAMA/A Reissued Jan.

[UNITED STATES fRe. 22,593 I PATENT OFFlCE "r'rm snme AND co vnn'roivnve on runs Alvin E. Montgomery, Elmhurst, 11]., as'signor to J. 0. Ross Engineering Corporation, New York, N. Y., a corporation or New York briginal No. 2,264,542, dated December 2,1941,

Serial No. 210,378, May 27, 1938.

Application for reissue January 12, 1843, No. 472,110 '12 mm. (cl. 92-68) a predetermined moisture content uniformly distributed throughout the material in the shortest possible time. a

Paper rroma paper-forming machine usually is of insuificient moisture content to render itadaptable for certain uses and its moisture content usually is not uniformly distributed. Ac-

cording to this invention, moisture is added to the paper by impinging it with hot, high humidity air under such condtions'as to cause condensation oi. a deposit of moisture on the surface of the paper. For example, by impin a sheet of paper with a conditioning-air stream 01 95 F. temperature and 90% relative humidity, the paper being of approximately 75 F. temperature, a.

surface deposit isiormed on the sheet in the matter of a very low seconds and the temperature of the sheetis brought up very close to the I dewpoint temperature ofthe air. From then on,

' moisture can be absorbed into the sheet only by the slow process 01' approaching equilibrium. The moisture provided by the surface deposit is less than is-required to give the sheetthe desired moisture content. Therefore, to supply the proper moisture content to the paper. the sheet of paper,

, after being subjected to the treatment above de-.

scribed, is cooled to approximately its original temperature under conditions as to prevent appreciable evaporation of the deposited moisture and then is again subiectedto the above-described treatment with hot humid air. Preter-v ably, the sheet is cooled by impingement with cold air of high humidity, but may be cooled by any other suitable means. The sheet is sub- Jected to repeated cycles or the treatment above described until it reaches the moisture content. Each treatment of the cooled paper with the hot humid air is eilected in'a short period .while each cooling operation likewise requires onlyashort'periodso thatin the matter or a few seconds, the paper is brought to the desired condition or moisture content as only a relatively Jew passes oi the p per through the hot humid moisture. v v Other objects, novel lectures and advantages or the invention become apparent from the iollowing specification and accompanying draw- 'able mechanism (not shown) and is caused toadvance at apredetermined rate. Through the ing, wherein the single'flgure of drawing illustrates schematically on term 01 apparatus i'or treating paper according to the invention.

.The treating chamber I0 is divided into a cooling compartment ll and'a' moistening compart- .ment [2. In each compartment are provided a plurality of rolls II so arranged that the paper P passes back and forth in several reaches in the cooling compartment only and then' in subsequent reaches passes alternately throughthe cool-'- ing chamber and the moistening compartment and after its last e through the cooling compartment isdiscnarsed from the treating apparatus to a suitable take-up mechanism (not 16 shown). I

- In the cooling compartment is provided a plurality oi ducts II which are so arranged that each reach or paper-in the cooling compartment lies between two-ducts It. In the moistening com- 20, partment I! is provided a lesser number of ducts ii so arranged that each reach of paper in the compartment l2 passes between two ducts Ii. Both the ducts II and ii are supplied with a large number otrelatively small apertures through which air maybe discharged into contact with both sides 01 the paper duringeach e through each compartment. A s pply duct i0 is provided for delivering cold humid air to the ducts l4 and a supply duct II is provided for delivering .30 hot humid air to the ducts I5.

' An apparatus ll of usual construction is pro-- vided for supplying cold and preferably moist air of proper temperature to the duct I8 and an apparatus I9 of usual construction is provided for supplying to the duct l'l air having the proper moisture content and of the proper temperature.

An exhaust duct 20 is provided for discharging air irom both compartments ii and I2.

The paper to be treated is threaded around the rolls I! in the two compartments by suitduct Ii, cold moist air of a predetermined temperature is supplied to the ducts l4 and through the duct l1 heated air of predetermined temperature and moisture content is supplied; to the ducts II. The air thus supplied is caused to im-,

pinge on both sides or paper as it travels through the two compartnmnts. "air is required to provide it with the desired '3 which it leaves the paper-making The temperature of the air.

paper is first cooled in the compartment H to a predetermined temperature, for example, 75 F. and then is carried into the compartment I! where it is subiected to air preferably of 95 F. temperature and 90% relative humidity. The paper is'then returned to the cooling compartment where its temperature is again reduced and the cycle above described is repeateda predetermined number of times. During its. various passes through the moistening compartment, 9. surface film of moisture is deposited on the paper due to the fact that its temperature is below the dew point temperature of the air supplied to the ducts l5 and the temperature of the sheet is brought up. very close to the dew point After the temperature of the paper has nearly reached the dew point temperature of the air, no further moisture will be deposited except by the slow process of approaching equilibrium. The deposition of the surface film and the elevation of the paper temperature to nearly the dew point temperature of the air takes place in a matter of a' few secends and the paper speed and the length of its path in the compartn cut 12 is so determined that it remains in the compartment only long enough for such eflects to be accomplished. The paper absorbs the deposited moisture and is then returned to the compartment H for cooling and appreciable evaporation is prevented by the humid condition of the cooling air. Through successive treatments, the paper absorbs enough increments of moisture to provide it with the desired moisture content in comparatively short time as the alternate passages of the paper through the cooling compartment and moistening' compartment require only a few seconds each. I

It is of course understood that various modiiications may be made in the procedure above described and that other apparatus may be used without in any way departing from the spirit of the invention as defined in the appended claims.-

I claim:

1. A process for increasing the moisture content of a continuously moving strip of fibrous water-absorbent materiahwhich comprises passlng the strip through a zone and therein direct ing toward and impinging onto the strip surface a multiplicity of small'streams of air, regulating the temperature and relative humidity of the air streams and the introduction temperature or said strip so that the air stream temperature is higher than its dew point temperature and the strip introduction temperature is lower than the dew point temperature of the air' streams thereby causing condensation of a 11m of moisture ,on

the strip in saidzone, withdrawing the strip a from said zone prior to appreciable absorption of moisture into said strip by approaching equi librium and cooling said strip to approximately its introduction temperature without appreciable evaporation of moisture therefrom and repeating the treatment until the strip has absorbed the desired content of moisture.

2. The process according to claim 1 in which the cooling is eifected by contacting the strip with a current of cold air of relatively high himidity.

3. A process for increasing the moisture content oia continuously moving strip of fibrous water-absorbent material, which comprises passing the strip through a zone and therein directing toward and impinging onto the strip surface a. multiplicity of small streams of air or approximately 95 F. and of relativehumidity not less than introducing said strip into said zone at a temperature less than the dew point temperature of said air streams thereby condensing a film of moisture on the strip in said zone, withdrawing the strip from said zone prior to appreciable absorption of moisture into said strip by approaching equilibrium and cooling said strip to approximately its introduction temperature without appreciable evaporation of moisture therefrom and repeating the treatment until the strip has absorbed the desired content of moisture.

4. The process according to cla im 3 in which the cooling is effected by contacting the strip with a current of cold air of relatively high humidity.

5. A process for increasing the moisture content of a continuously moving strip of fibrous water-absorbent'material of predetermined temperature which comprises impinging the strip in a series of passes with air streams of not less than 85% relative humidity and of higher temperature than the initial temperature of the strip thereby condensing moisture from said air streams on said strip and increasing the moisture content ther of and after each passage cooling the treated s rip to a temperature below the dew point temperature of said air streams without appreciable evaporation of moisture'from 'said perature than the initial temperature of the strip thereby condensing moisture from said air streams on said strip and increasing the moisture content thereof, and after each pass contacting the treated strip with a current of air of lower temperaturethan the dew point temperature of said first mentioned air streams and of sufiiciently'high relative humidity to-prevent appreciable evaporation of moisture from said strip.

8. A process according to claim '7 in which the initial temperature of the strip is approximately 75 F. and the first mentioned streams of air are of approximately 95 F. temperature and relative humidity.

. 9. A processI'or increasing the moisture content of a continuously moving strip of paper which comprises the steps of flrst cooling the continuously advancing strip of paper to a temperature of approximately 75 F. by means of cold air-oi high humidity, then contacting the cooled paper strip with an atmosphere of hot air of a temperature of approximately F. and a humidity of approximately 90 per cent, and

- thereby condense .moisture out of said high humidity atmosphere onsaid cold paper and'increase the moisture content thereof.

10. Inthe process according to claim 9, the additional step of cooling the treated paper to a temperature of approximately '75 F. by means of cool air of sufiiciently high humidity to prevent appreciable evaporation of moisture from the paper. 7

a 11. A process for increasing the moisture content of a continuously moving strip of freshly made paper which comprises cooling the continu-.- ously advancing strip of paper to approximately 75' E, passing the cooled strip through a zone and therein directing toward and impinging onto the cooled paper a multiplicity of small streamsoi air or approximately 95 F. and of relative humidity not less than 85% thereby condensing a film v or moisture on said paper, withdrawing the strip from said zone prior to appreciable absorption oi moisture into said strip by approaching equilibrium and eooling the treated paper to approx imately 75 F. without appreciable evaporation of moisture therefrom and repeating the treatment until the paper has absorbed the desired content of moisture.

12. Theprocess according to claim 11 in which the initial and final cooling is eflected by contacting the paper with a current of cold air of high relative humidity.

ALVIN E. MONTGOMERY.