US3274697A

US3274697A - Method for conditioning web- or sheetlike material

Info

Publication number: US3274697A
Application number: US349535A
Authority: US
Inventors: Aronsson Arent
Original assignee: Svenska Flaktfabriken AB
Current assignee: Svenska Flaktfabriken AB
Priority date: 1964-03-02
Filing date: 1964-03-02
Publication date: 1966-09-27
Anticipated expiration: 1983-09-27

Description

Sept. 27, 1966 A. ARONSSON 3,274,697

METHOD FOR CONDITIONING WEB- OR SHEET-LIKE MATERIAL Filed March 2, 1964 FIG. I.

INVENTORZ ARENT ARONSSON widmwmw ATTYS.

United States Patent 3,274,697 METHOD FOR CONDITIONING WEB- 0R SHEET- LIKE MATERIAL Arent Aronsson, Nacka, Sweden, assignor to Aktiebolaget Svenska Flaktfabriken, Stockholm, Sweden Filed Mar. 2, 1964, Ser. No. 349,535 7 Claims. (Cl. 34-36) This invention relates to a method for conditioning webor sheet-like material. In the case of hygroscopic webor sheet-like material the conditioning has as its primary object to bring the moisture ratio into balance with normal storage atmosphere. Where the webor sheet-like material comprises paper, such a conditioning of the paper is also required with regard to the stability requirements the paper has to meet for printing and the like. The prior art illustrates many ways in which conditioning may be carried out, for example 'by supplying the moisture in a finely divided form, through nozzles or by passing the material through a chamber having a steam atmosphere.

When applying the first-mentioned method, i.e. by applying moisture via nozzles, difficulties arise in obtaining uniform distribution of the moisture throughout the web, and there is, furthermore, great risk of stain formation, particularly in material having a sensitive surface. Conditioning in a steam atmosphere on the other hand, includes the risk of stain formation due to partial condensation and renders it, moreover, difficult to carry out the conditioning without an undesirable increase in temperature. The best conditioning method heretofore known is to pass the material through a closed room, where it is exposed to the effect of moist air of suitable saturation. This method requires, however, a long treatment time, due to the temperature increase in the material caused by the moisture condensing therein and the reduction of the relative humidity of the air resulting therefrom.

The method according to the invention has as its principal object the elimination of the last mentioned disadvantages and is characterized in that the moisture is supplied to the material by blowing a heated, moist, gaseous medium against one surface of the material while at the same time blowing a cold, moist gaseous medium against the opposite surface of the material, thereby continuously conducting away the heat released by the condensing moisture. The moisture supplying medium may be heated moist air or steam. The treatment is preferably carried out in several different steps, by providing separate consecutive treatments wherein the moisture supplying medium is of different condition.

The conditioning may be carried out such, that for each step or treatment the blowing side for the heated, moist medium and the cold, moist medium respectively is changed. In order to prevent mixing of the said two media, the treatment is preferably carried out in an entirely closed chamber, the said media being supp-lied such that in said chamber an overpressure is maintained on both sides of the web, and that at least part of the two media is sucked off from the chamber through openings provided along the two side edges of the web.

Other objects and a fuller understanding of the invention may be had by referring to the following specification and claims taken in conjunction with the accompanying drawing in which:

FIG. 1 is a schematic longitudinal sectional view through apparatus which may be used to practice the method of the present invention; and

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1 as if FIG. 1 were not in section.

Referring now to the drawing, a housing or casing 1 for a treating apparatus, designed as a closed chamber,

is divided into three separate sections A, B and C and provided with a feed opening 2 and a discharge opening 3 for a continuously advanced material 4. During the passage through the chamber a heated, moist, gaseous medium is supplied to the material, which medium according to the invention is blown against one surface of the material, in the example shown against the upper surface thereof. The medium is supplied by means of circulation fans 5, each of said sections including a fan 5 driven in the present instance by a directly connected electric motor 6. The fan presses the medium into an air distribution box 7 arranged above the web, the surface of the box facing the web being provided with a plurality of uniformly spaced air supply openings 8. The medium blown against the web is returned to the circulation fan through a plurality of exhaust or discharge passages designed as tubes 9, which pass through the said air distribution box and open into a suction chamber 10 communicating with the inlet of the fan. As illustrated in FIG. 2, for heating and, if required, humidifying the treating medium, means 11 are provided.

According to the invention, a cold, moist, gaseous medium is blown against the opposite surface of the web simultaneously with the supplying of the heated medium. For this reason, each of the sections is also equipped with a second circulation fan 12, which is directly conneeted to a mot-or 13 and forces the cold medium into a distribution box 14 arranged below the web. In a manner similar to above, the distribution box 14 is provided with air supply openings 15 and exhaust or discharge passages 16, which open into a suction chamber 17. The temperature of the cold medium is controlled by cooling means 18.

As both cold and warm media is supplied simultaneously to opposite sides of the web, means must be provided to prevent inadvertent mixing of the media by passing around the longitudinal edges of the web. To this end it is advisable that at least a part of the two media is discharged or sucked off from the chamber through openings provided along the two longitudinal edges of the web. As illustrated in FIG. 2, shield bars 19 on both sides of the web edges prevent mixing of the two separately supplied media. The said bars are preferably designed such, that they form a longitudinal passage for sucking off a small part of each of the media.

Although the invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example, and that numerous changes in the apparatus utilized in carrying out the method may be made without departing from the spirit and the scope of the invention as hereinafter claimed.

What I claim is:

1. A method of conditioning web or sheet-like material in a. chamber comprising the steps of: feeding the material to be treated through said chamber, blowing a heated, moist, gaseous medium against one surface of the material, blowing a cold, moist, gaseous medium against the opposite surface of said material to thereby conduct away the heat released by the condensation of moisture in and on the material.

2. A method in accordance with claim 1 wherein the heated, moist, gaseous medium comprises heated, moist air.

3. A method in accordance with claim 1 wherein the heated, moist, gaseous medium comprises steam.

4. A method in accordance with claim 1 including the steps of dividing the chamber into at least two sections, and supplying the heated, moist, gaseous medium in each of said sections at different conditions.

5. A method in accordance with claim 1 including the step of-discharging at least a portion of the two media from the chamber at points closely adjacent the longitudinal edges of the material.

6. A method of conditioning Web or sheet-like material in a substantially closed chamber, comprising the steps of: dividing the chamber into at least two sections, feeding the material through said sections consecutively, supplying moitsure to the material in each section by blowing heated, moist, gaseous medium against one surface of the material in one of said sections and against the opposite surface in the other of said sections, and simultaneously therewith blowing cold, moist, gaseous medium against the opposite surface of said material in said one section and the surface of said material in the other of said sections.

7. A method of conditioning web or sheet-like material in a substantially closed chamber, comprising the steps of: dividing the chamber into at least two sections, feeding the material through said sections consecutively, supplying moisture to the material in each section by blow- References Cited by the Examiner UNITED STATES PATENTS 2,123,341 7/1938 Often 34-13 X 2,297,314 9/1942 Offen 34-37 X 2,682,116 6/1954 Dungler 3437 X FREDERICK L. MATTESON, IR., Primary Examiner.

JOHN J. CAMBY, Examiner.

Claims

1. A METHOD OF CONDITIONING WEB OR SHEET-LIKE MATERIAL IN A CHAMBER COMPRISING THE STEPS OF: FEEDING THE MATERIAL TO BE TREATED THROUGH SAID CHAMBER, BLOWING A HEATED, MOIST, GASEOUS MEDIUM AGAINST ONE SURFACE OF THE MATERIAL, BLOWING A COLD, MOIST, GASEOUS MEDIUM AGAINST THE OPPOSITE SURFACE OF SAID MATERIAL TO THEREBY CONDUCT AWAY THE HEAT RELEASED BY THE CONDENSATION OF MOISTURE IN AND ON THE MATERIAL.