Method and apparatus for the freeing from water
US 1802407 A
Description (OCR text may contain errors)
Apnl 28, 1931. A. DANNINGER ET AL 1,802,407
METHOD AND APPARATUS FOR THE FREEING' FROM WATER OF WEBS OF PAPER, GELLULOSE,AND THE LIKE Filed Sept. 4, 192a Patelited Apr. 28, 1931 UNITED STATES PATENT OFFICE,
ALOIS DANNINGEB,'HERBIBT SCHMOLKA, AND RICHARD KASTNER, OF STEYRERMUHL,
' AUSTRIA METHOD AND APPARATUS FOR THE FREEIZNG FROM WATER OF WEBB OF PAPER,
OHIJULOSE, AND THE LIKE Application filed September 4, 1828, Serial No. 303,758, and in Austria September 12, 1927.
As it is known, webs of paper, cellulose and the like are passed through wet-presses for leading off in a mechanical way as much as possible of the water contained in the web in order to be able to execute the subsequent dr ing in the usually steam-heated dryingcy inders with a lower rate of heat. The quantity of the water removed from the paper or cellulose web by means of the wetpresses could be increased by this that the paper or cellulose web is heated within the wet-press-system, that is before the last wetpress, with the efl'ect to reduce the viscosity of the water. However, this intermediate heating in the wetprcss-system cannot be carried out in the manner usual in papermachines, that is to say by means of heated cylinders for the following reason: As well known in-the art the webs of paper or cellulose have still a high water-content (80 to 90 per cent and more) before the last wet-press and for heating these relatively great quantities of water in a very shortvtime to a temperature of 60 to 80 C. the heating cylinders must have a high temperature. By the con tact with the hot cylinders the webs of paper or cellulose which in consequence of their high water contents are still very liable to be affected would become defective and furthermore in some cases the gluing of the paper or cellulose web would be unfavourably influenced by the excessive heating of the outermost fibers which are in contact with the heating-cylinders.
According to the present invention the heating of the paper or cellulose web is brought about within the wet-press-system, that isto say before the last wet-press, by means of heating elements preferably acting by radiation of heat and in a preferred form constructed as electric radiation heating elements, which are free from any direct contact with the web. In this way all detrimental actions on the paper or cellulose web are prevented.
A further feature of the invention consists in the fact that the part of the web-paper or cellulose web itself, which is situated just in front of the wet-presses, serves as an electric resistance heating element. The current passing through this part of the web heats the paper or cellulose web together with the water contained therein. For the intermediate heating of the paper or cellulose web within the wet-press-system superheated steam or hot air or a mixture of steam and hot air may also be used.
The invention also relates to the apparatus for carrying out the new method.
In the drawing which illustrates a constructional form of the apparatus according to the invention, the figure shows a view of a device for the intermediate heating of the paper or cellulose web by means of electric radiation heating elements.
In the form of construction shown in the figure the paper or cellulose web a which arrives in the usual manner from the wetsystem (sieve-system or the like, first wetpresses) of the paper machine or the like and 7 which has still a very high water content is carried over two rolls 6, 0 before it comes tolthe last wet-press d, f. On the one side of the wet-paper or cellulose web a a series of electric radiation heating elements is provided which for example consists of resistance wires 9 supplied by electric current. These resistance wires g extend preferably over the whole breadth of the paper or cellulose web a and are arranged in reflectors h of parabolic cross-section which have the form of soffits, that means that the reflectors h extend also over the whole breadth of the web. On the other side of the paper or cellulose web a a reflector z in the form of a screen is provided, which reflects the rays of heat passing for a part through the web a, so that the web a is radiated from both sides without the necessity of arranging the radiation heating elements also on both sides.
The described apparatus enables a very intensive supply of heat to the wet paper or cellulose web a, so that the water content of this web is heated to a temperature of 60 to 80 C. notwithstanding the great speed of the web (about 2 to 5m/sec) and notwithstanding the radiation taking place for some seconds or for fractions of seconds only. The paper or cellulose web becomes in this manner uniformly heated through its entire thickness without any detrimental action on the web. By means of the intermediate heating the viscosity of the water contained in the web a is reduced so far that the following wet-press d, f is capable to press off a quantity of water which is much greater than it wouldbe the case without the intermediate heating. The paper or cellulose web leaves the wet-press with a much higher degree of dryness, so that the amount of heat WhlCh must be supplied in the following dryingsystem of the paper-machine is considerably reduced.
In case of interruptions of the working, for example on breakage of the paper or cellulose web a this web would become completely dried under the action of the radiation heating elements 9 or the web could come in contact with the said heating elements 9, with the risk that the web catches fire. For preventing this, screening devices are provided, which are situated in front of the reflectors h and which have in the illustrated example the form of flaps j which are connected for common operation by a lever system m. In case of interruptions of the working,--for example on breakage of the web a the flaps j are closed .by hand or by means of an automatic device.
Itwill-be understood that the arrangement may also be such that in case of interruptions of the working the radiation heating elements g themselves will be automatically switched off.
It is self-evident that the heating elements 9 may be heated also in another way than by means of electric current so as to bring about a sufliciently intensive radia-' tion of the paper or cellulose web a.
The intermediate heating of the paper or cellulose web in the wet-press-system may be effected according to this invention also in such a manner that the wet-felt travelling together with the paper or cellulose web is heated simultaneously with this web or is heated alone. The wet-felt ma be heated in the described manner by ra iation, that means indirectl or it may be in contact with the heating cylinder whilst only the heating of the paper or cellulose web' is effected indirectly. In this form of the method a partiall drying of the wet-felt is obtained that wi 1 be advantageous for the working and for the life of the felt.
What we claim is:
1. An apparatus for removing superfluous water from webs of paper and cellulose, comprising a wet-press, a series of rolls for carrying the wet-web to said ress, heating elements having highly efiectlve radiation, said elements being uniformly spaced along one side of the path of the web and reflectors for each heating element adapted to carry the heat against the surface of the web, and another reflector on the opposite side of the web adapted to return heat waves site side of the web adapted to return to the web hav' passed through the same from the first re ectors.
2. An apparatus for removing superfluous water from webs of paper and cellulose, comprising a wet-press, a series of rolls for carrying the wetweb to said press, heating elements having highly efiective radiation, said elements being umformly s aced along one side of the path of the we and parabolic reflectors for each heatin element ada ted to carry the heat against t e surface of t e web, and a flat reflector on the o poeat waves to the web having passed through the same from the parabolic reflectors.
3. An apparatus for removing superfluous water from webs of paper and cellulose, comprising a wet-press, a series of rolls for carrying the wet-web to said press, heating elements having highly effective radiation, said elements being uniformly s aced alon one side of the path of the we and para olic reflectors for each heating element ada ted to carry the heat against the surface 0 the web, and a flat reflector on the opposite side of the web adapted to return heat waves to the web having passed th'rou h the same from the parabolic reflectors, an flaps hinged to the edges of the arabolic reflectors and adapted to close in ront of said heating elements in order to regulate the heat passing from the parabolic reflectors to said web.
4. A method of removing superfluous water from a wet-web consisting in carrying said web past highly effective heating ele-' 'ments at a speed 0 approximately 2 to 5 meters per second and exposing the web to heat of 60 to C., and finally pressing the web between suitable rollers.
In testimony whereof we have afiixed our signatures.
ALOIS DANNINGER. HERBERT SCHMOLKA. RICHARD KASTNER.