US1870166A

US1870166A - Process of preparing comminuted cork

Info

Publication number: US1870166A
Application number: US422665A
Authority: US
Inventors: Samuel C Bond
Original assignee: HENRY P SCOTT Co
Current assignee: HENRY P SCOTT Co
Priority date: 1930-01-22
Filing date: 1930-01-22
Publication date: 1932-08-02
Anticipated expiration: 1949-08-02

Description

Aug. 2, 1932. s. c. BOND 1,870,166

PROCESS OF PREPARING COMMINUTED CORK Filed Jan. 22, 1950 r0 l/YDE s 575A Patented Aug. 2, 1932 UNITED STATES PATENT OFFICE SAMUEL C. BOND, OF HOLLY OAK, DELAWARE, ASSIGNOR TO THE HENRY P. SCOTT COM- PANY, A CORPORATION OF DELAWARE, .AS TRUSTEE PROCESS OF PREPARING COMMINUTED CORK Application filed January 22, 1930. Serial No. 422,665;

My invention relates to an improved process of preparing comminuted cork.

The main object of my invention is to provide an improved process of preparing comminuted cork, which results in the comminuted cork having a uniform low moisture content. This low and uniform moisture content'is very desirable in the manufacture of articles of molded comminuted cork, to reduce subsequent shrinkage of such articles. A further object of my invention is to provide an improved process for preparing comminuted cork, which results in a moreefficient separation of the ground cork from the exli traneous matter, or hard material, contained in the waste cork used as the raw material in this process. A further object of my invention is to provide a process for preparing comminuted cork. in which the particles of cork material are toughened before comminution so as to put them in abetter condition for subse uent treatment.

urther objects, and objects relating to details and economies of operation, will definitely appear from the detailed description to follow. In one instance, I accomplish the objects of my invention by the means described in the following specification. My invention is clearly defined and pointed out in the appended claims. The single figure of the accompanying drawing, forming a oart of this specification, illustrates diagrammatically an apparatus by which my invention may be carried out.

Heretofore, it has been the practice to prepare comminuted or ground cork from waste cork, or cork material, by subjecting this raw material to successive cutting and grinding operations, reducing the particles to the desired size, and to a separating action by which the hard material of extraneous matter contained in the raw material is removed. The waste cork constituting the raw material contains more or less hard material, known as hard back which must be separated from the cork. After the material has been ground this can be accomplished by centrifugal separators, since the hard material is brittle and 50 is ground to a dust which is readily separated from the lighter and larger particles of cork.

However, the waste cork frequently contains a good deal of moisture, which it is desirable to remove as completely as possible, so that the ground cork may have a uniform low moisture content. It has been the practice, heretofore, to dry the waste cork by a blast of hot air, but this has resulted in baking the surface of the cork, making it brittle so that some of the cork islost in the separation process. being removed with the hard material.

In general. my invention consists in subjecting particles of the cork material to the action of an atmosphere of steam which is at a temperature above the boiling point of water at atmospheric pressure, and subsequently subjecting these particles to the grinding operation. I propose to treat the waste cork, so as to form particles of substantially uniform size, and these particles are then conveyed to a storage bin into which live steam is conducted. This steam is continuously withdrawn from the bin by a suitable exhaust fan, which reduces the pressure in the bin slightly below atmospheric pressure. The steamed and. thus heatedparticles are then led off through a measuring device, which prevents the escape of steam from the storage bin to the grinders in which the cork is reduced to particles of the desired size and the hard material is separated, any excess I moisture remaining in the cork being liberated during and directly after the grinding operation. The steam within the bin may be superheated or saturated, but should have super-heat at the time of original contact with the material, and for the sake of economy should be saturated at the time of leaving the material being dried. Having displaced all water, air or other volatile liquids. the weight or amount of the remaining water is equal to the weight of the equivalent number of cubic feet of steam in theabove mentioned steam atmosphere, and can be readily determined from tables giving the properties of steam. I

Referringto the accompanying drawing, which illustrates diagrammatically an arrangement of apparatus for carrying out my lmproved process, waste cork 1s fed into the v 12 having a hopper bottom 13.

breakers in which it is reduced to particles of substantially uniform size, such as will pass through a screen having a three-quare ter inch mesh. These breakers operate by cuttingaction, with as little crushing as possible, and are well known in the art. From the breakers, the particles of cork are conveyed by pipe'll to a covered storage bin The discharge outlet for the particles of cork material is at the bottom of this bin and a rotating measuring device l l delivers the particles into the pipe by which they are conveyed to the grinders for the subsequent grinding and separating operations. This measuring device 14 acts as a seal for the bottom of the bin preventing the escape of steam into the pipe 15. Live steam under pressure above atmospheric is led into the lower part of the bin through the pipe 16 and acts upon the particles of cork in said bin. An exhaust pipe 17, communicating withthe inlet of an exhaust fan 18 is connected to the upper part of the bin so as to draw the steam continuously from the bin and discharge it through the pipe 19. The saturated steam under pressure injected into the bin through pipe 15 immediately becomes superheated because its pressure is reduced to atmospheric pressure or slightly below. The excess heat in this superheated steam vaporizes the moisture contained in the cork. this case it is desired to have the cork substantially bone dry. Therefore, the point of cork discharge is adjacent to the steam inlet, and at the same time, the cork is as dry as the steam and so hot that the little water present as steam is evaporated after assing the measuringdevice. will be noted that the drier cork is in contact with the dry steam and the wet cork with the wet steam.

The result oi subjecting the particles of cork to the action or steam before grinding them is to toughen the cork, so as to make it more soft and resilient and put it in a better condition for the subsequent grinding operation. The steam acts on the cork, and not on the particles of hard material carried by the Waste cork, and, consequently, a more efficient separation of the cork from the hard material is secured. l have found in practice that I secure approximately ten per cent greater yield of cork where this'process is used, and I believe this to be due to the fact that none of the cork is -n1a le brittle and crushed to dust with the hard material. Furthermore, the steam acts to eliminate the excess moisture in the cork, with theresult that the particles of cork have a uniform low moisture content. This is very desirable because itreduces the amount of shrinkage in the articles molded from this comminuted cork.

I am aware that the method herein described may be chan ed considerably without departing from t e spirit of my invention and, therefore, I claim my invention broadly as indicated by the appended claims.

What I claim is:

1. The process of refining crude cork having resilient and non-resilient components, which comprises subjecting the crude cork to an atmosphere of hot water vapor to toughen the resilient portions thereof, grinding the thus treated cork to effect granulation of the resilient portions and pulverization of the non-resilient portions, and separating the granulated resilient material from the pulverized material.

2. The process of refining crude cork having resilient and non-resilient components and an excessive moisture content, which comprises breaking up the crude cork into small pieces of substantially uniform size, passing superheated steam into intimate contact with said pieces eflecting heating of said pieces and toughening of the resilient portions thereof, grinding said pieces while still hot to granulate the resilient portions and pulverize the non-resilient portions and thereby allowing the granulated resilient portions to release entrapped moisture, and separating the granulated resilient cork from the pulverized non-resilient material.

SAMUEL G. BOND.