US 1725465 A
Description (OCR text may contain errors)
Aug 20, 1929 G. J. MANsoN 1,725,465
'METHD OF AND APPARATUS FOR DRYING PULP ARTICLES Filed Deo. 8, 1927 div i l l0 J" ed I f I H f/Z l /M/fA/rap.
650065. M4/usan /9 M www Patent-ed Aug. 20, UNITED STATES 1,125,465 PATENT OFFICE.
GEORGE JAMES MANSON, OF HAWKESBURY, ONTARIO, CANADA.
METHOD OF AND APPARATUS FOR DRYING PULP ARTICLES.
.Application led December 8, 1927. Serial No. 238,659.
This invention relates to an improved method of and apparatus for drying pulp articles, and the objects of the invention are toy rapidly and economically dry pulp articles without distorting the same, or spoiling the surface thereof; and it consists essentiall of drying articles through the heat pro uced by electrical currents induced in the portion of the die adjacent to the article, all as hereinafter more fully set forth and described in the accompanying specification and drawings.
At present articles made from pulp fibres are taken from the forming machines and are dried by subjecting the article to hot air in a closed chamber, er by carrying the article on a moving belt through a chamber containing hot air. These chambers may have steam coils in them, to heat the drying air or air which'has been heated outside of the chamber may be continuously circulated through the chamber. When a pulp article is dried by these methods, it is likely to come from the drier a little distorted and with a rather rough surface.
Attempts to dry pulp articles in dies heated by resistance coils directly connected to al source of electrical energy have been tried, but it has been impossible due to the small size of the dies, to get enough energy into them to be able to operate the dies continuously and make theprocess commercial. 1y feasible.
I have found that if the dies containing the article to be dried are placed in -a strong magnetic field which will induce a current in the part of the die next to the pulp article, the pulp article will be dried very rapidly on account of the high temperature to whichl the adjacent part of the die is raised by the heavy induced current. v Practically any shaped article can be more rapidly and economically dried by this method than by hot air. The finish of the article is much better and there is no distortion of the shape of the article.
In the drawings, Figure 1 is'an elevation of one form of apparatus in which the invention may be carried out. i
Fi re 2 is a sectional elevation through the evice with the pulp article therein.
Figure 3` is a plan view of one of the dies. Referring Ato the drawings, A indicates a t of transformer which may be used to evelop the necessary magnetic eld, having able that as heav inafter referred to.
It will be understood that the form of transformer is shown by wayof illustration only, and may be varied to suit the conditions, and that any other well known type of transformer may be used. .Figure 2 shows a section through the drylng dies, of which l5v is the upper and C the lower die, preferably formed of wrought iron or mild steel, and faced on the surface adjacent to the pulp article with metal of high conductivity such as sheet copper, the facing of sheet copper being indicated at 14 and 15.
It is desirable to guard against the formation of eddy currents in thev dies' B and C, and this may conveniently be done by slotting the dies as lshown by radial slots 16 in the dies for this purpose. The copper linings 14 and 15 are not slotted, as it is desira current as possible should flow throng 1 them.
faces 14 and 15 andl may be either formed therein by pressure between the dies exerted in suitable hydraulic press or may be placed in the dies after being transversely formed in another press.
lVhen it is desired to dry the article, the dies B and C containing the same, are placed between pole faces A1 and A2 of the trans former A, and the coils 11 and 12 are excited .by alternating current passed therethrough,
the magnetic force produced from this current flowing between the faces A1 and A2 through the dies B and C, and causing a heavy current to be induced in the copper plates 14 and 15, causes these plates to rapidly increase in temperature, giving up heat` The pulp article 17 is located between the I 'As many changes could be made in the above construction, and many apparently widely different embodiments of my invention, within the scope of the claims, con-X, structed without departing from the spirit or scope thereof, it is intended that all matter contained in the accompanying specification and drawings shall be interpreted as illustrative and not in a limiting sense.
What I claim as my invention is:
1. The herein described method of drying4 pulp articles, comprising -placing the same between a pair of dles and lnducing heavy secondary Ielectrical current 1n the dies and expelling the moisture therefrom.
2. The herein described method of drying pulp articles, lwhich comprises lacing the same between dies, heating surfaces of increased electrical conductivity and inducing heavy secondary electrical heating currents in the surfaces.
3. The herein described method of drying pulp articles, which comprises placing the article between apair of dies, inducing heavy secondary electrical heating current in the gies, then exerting a pressure between the ies.
4. An apparatus for the purpose specified, comprising a pair of dies having copper facesadjacent to the article to be dried, and means for inducing electricall currents in the said faces.
memes- 5. rhe'herein described method of drying a pulp article, which comprises placing the same between a pair of dies adapted to allow the evaporated water to escape therefrom, forming a complete magnetic circuit including a portion of the die surface, inducing a heavy secondary electrical current' in the said magnetic circuit to thereby heat the pulp' article and expel the moisture thererom. 6. An apparatus Vfor the purpose specified, comprising a pairpof dies adapted to permit the escape of vapour therefrom, a magnetic circuit associated with the dies including part of the die surface, means for inducing a heavy secondary electrical current in the said magnetic circuit to heat the part in the die and expel the moisture therefrom out of the die.
7. In an apparatus of the character described, a pair of dies, having means adapted to guard against the formation of eddy currents therein, and adapted to permit the escape of moisture therefrom, a magnetic circuit associated with the dies, and means for inducing a heavy secondary `current in the said magnetic circuit to heat,the article in the dies and expel the moisture therefrom.
8. An apparatus for the purpose specified comprising a transformer having opposite pole faces between which dies are-adapted to lit, a primary heating c oil surrounding the pole faces, a pair of dies adapted to iit between the pole faces and to have electrical currents induced therein by the said primary windings, means for exerting a pressure 'between the -pole faces, and the dies provided with copper working surfaces.
In witness whereof I have hereunto set my hand. l
. GEORGE JAMES MANsoN.