US1977045A - Process of drying laminated paper material or boards - Google Patents

Description

.Oct. 16, 1934. 1c, CORCORAN 1,977,045

PROCESS OF DRYING LAMINATED PAPER MATERIAL OR BOARDS Filed Sept. 12 1931 ii?? i. {Ema/n21.

Patented Oct. 16, 1934 UNITED STATES PATENT OFFICE PROCESS OF DRYING LAMINATED PAPER MATERIAL OR BOARDS John C. Corcoran, Worcester, Mass, assignor to Superior Tool & Manufacturing (10., Inc., Worcester, Mass a corporation of Mmhllr' setts The present invention relates to the manufacture of laminated paper material known in the art as boards" of various kinds, such as have been made by building up layers of paper on a wet machine until the desired thickness of board is secured, or by superposing separate sheets of paper with adhesive therebetween. The object of the present invention is to provide an improved process-of drying sheets of paper boards 0 in such a manner as to deliver the dried boards in flat condition.

In the manufacture of paper boards of various kinds, as previously carried out, it has been customary to dry the separate sheets by merely .5 hanging the same so as to be suspended in the air, and it has been found that this manner of drying the sheets often causes them to warp and twist out of shape. Since any appreciable warping or twisting of the sheets of board renders them unsuitable for commercial use, it has heretofore been necessary to flatten the sheets after drying, thereby adding materially to the cost of production.

According to the present invention, there is 25 provided an improved process of drying built up paper boards of various kinds-characterized by the progressive drying of the boards while preventing any warping or twisting of the same, so that the dried boards are delivered in fiat conso dition. The above and other advantageous features of the invention will hereinafter more fully appear from the following description with reference to the accompanying drawing, the single\ figure of which is a diagrammatic representation of one arrangement of instrumentalities for carrying out the process.

Referring to the drawing, a number of rotatably mounted drying cylinders 1, 1 are provided, around which pass drying aprons 2 and 3, preferably composed of felt. The aprons 2 and 3 pass back and forth between the cylinders 11, 1 in contact throughout, suitable tension devices 4 being provided above and below the cylinders for keeping the aprons taut. The lower apron 2 extends beyond the front cylinders l, where it passes around a guide roll 5, thereby providing a board receiving portion 241 that is entirely free from the downwardly moving upper apron 3.

-5 The other end of the apron 2 is extended beyond adapted to be heated in any suitable manner, as by the admission of steam thereto.

In carrying out the process of the present invention by means of the arrangement of appsratus described above, sheets of board 9 such as have been formed on a wet machine by building up layers of paper, or such as have been formed by superposing separate sheets of paper with adhesive therebetween, are delivered one by one in a moist condition to the receiving portion 2a. of

the lower drying apron 2. Movement of the receiving portion 2a of the apron in the direction of the arrow will carry each board 9 into the bight between the two aprons 2 and 3 as the aprons pass around the lowermost drying cylinder 1. As the sheets of board 9 enter between the aprons 2 and 3, the sheets are held tightly in place, without any possibility of warping or twisting, and are maintained in this condition as the aprons pass around the drying cylinders 1. It is evident from a consideration of the drawing that the cylinders 1 are arranged in such a manner that first one side and then the other of each sheet of board is curved around a drying cylinder, so that the drying takes place evenly due to the reversal of the sheet with respect to the heated surfaces of the cylinders. Throughout the travel of each sheet of board, it is never subjected directly to the heated surface of a cylinder, due to one or the other of the interposed aprons which extract the moisture of the boards and evaporate the same.

Obviously, the evaporation of the moisture taken up by each apron is carried out evenly, since portions of first one apron and then the other are alternately exposed to a heated cylinder and then to the air. as they pass around the cylinders. It has been found that the pyramidal arrangement of the drying cylinders, as shown on the drawing, insures a maximum degree of contact between the aprons and the cylinders, with opportunity for the surfaces of both aprons to be subjected to the drying action of the air, both above and below the cylinders.

After passing completely through the rolls while confined between the drying aprons 2 and 3, each sheet of board 9 emerges from between the bight of the aprons at the lowermost cylinder 1 and rims out in an absolutely flat condition to the horizontal delivery portion 2a of the lower apron. By this time the sheet of board is thoroughly dry, and the movement of the apron portion .2ain the direction of the arrow delivers each board to the table '7 in an absolutely flat condition.

From the foregoing, it is apparent then that by the present invention there is provided an improved process of drying built up paper boards of various kinds, so that each sheet of board is delivered thoroughly dried and in a flat condition. Furthermore, each sheet of board resulting from the practice of the process is of uniform character throughout, owing to the travel of the board between the aprons with first one side and then the other subjected to the drying effect of a heated cylinder. While I have shown a preferred arrangement of apparatus for carrying out the invention, obviously such apparatus is susceptible of modification without departing from the principle underlying the process, as set forth in the appended claim.

JOHN C. CORCORAN.

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