US1624471A - Process for forming articles from comminuted material - Google Patents

Description

Patented 12, 1927,

' UNITED STATES PATENT ,OFFICE,

-,HIIQLHOUSE FUEL, OF, SEATTLE, WASHINGTON, ASSIGNOB- OF ONE-HALF TO WILLIAM r. HAMMOND, or SCARSDALE, NEW-YORK.

PROCESS FOR F ORML I NG ARTICLES FROM COMMINUTED MATERIAL.

No Drawing. Continuation of applications Serial No. 115,086, filed August 15,1916, and serial 110. 185,185,

filed April 28, 1917. a This application filed October 10, 1917. Serial No. 195,726.

The principal object of my invention is to provide a practical process for forming articles from comminuted material by flowing such material against a foraminous mold wall;

()ther objects of my invention will more fully appear hereinbelow,

It has heretofore been proposed to manufacture articles froln a pulpy mass by flowing the pulp againstaforaminous mold surface, but a great many diff culties have been encountered, both technical and commercial.

For instance, it has been the universal experience of persons attempting to produce articles ona commercial scale by flowing ipulp against a stationary mold surface that the percentage of voidsinthe Walls of the article has been so high as to make such article valueless. If the water remaining in A said voids is 'dried outby air or heated gases,

the walls are weak and will readily reabsorb -water. When it has been attempted to remove this latter defect by treatment with filling substances, the cost has been prohibi+ tive owing to the large amount of filler aband the article has still cessive inter-fibre spaces or voids in relation to the small amount of'solids therein. When it has been attempted to expel the water held in the walls of the article by pressing them between dies, it has been found impossible to reduce the percentage, of water ,in the material below fifty per I cent; even when the pressure is measured in tons. In view of the difiicultiesl mentioned,

it has heretofore been diflicullnto maketan article from pulp of suflicient strength to be.

useful, except where made upon a core, and there are no articles on the market made by depositing comminuted materlal on a mold surface which have a-relatively restricted mouth, owin to the present necessity of compacting the articles by pressure dies. Y

process consists in flowing comminutedmateria'lagamst the entire inner surface of a stationary,- toraminous holder, screen or moldfdevo d-ofacore, under a super-atmosphericp" 'ressuresuflicient to form and com-- actjthe ;--.walls"of the article in one step, deposition,; t the solid elements occurring in contrast to said prior processes my simultaneously throughout the mold surface and continuing with the delivery of the fluid to the mold; When using a liquid or gaseous pulp subsequent application of a fluidic pressure medium, ,as heated air or superheated steam, is necessary as a second ste when the surplus material is discharge from the mold, to maintain the compactness of the deposited material and to further compact all portionsof the same simultane ously, as the moisture is expelled from the deposition and vaporized therefrom by the" fluidic medium as it escapes thru the pores of the deposition. I may also introduce treating material into the mold as a third step of the process after the surplus comminuted material has left the mold and the deposition is sufliciently compacted, a convenient way of doing this being to introduce the treating material for :water proofing, or other purposes, as a liquid, so that the' treating and curing of all portions of the deposited body may also proceed simultaneously While the deposition is still held -undisturbed in the mold under pressure. It will be understood that all the steps of-my process follow in rapid sequence. I

It 'is necessary that the pressure with which, the comminuted material is introduced into the mold be maintained. sulficiently high that each layer of material deposited shall be dense and strong, and that each succeeding layer shall be strong itself and be securely interlocked with the mate-' rial prev ously deposited. This high pressure not only securely interlocks the solids deposited, but also reduces the voids and percentage of contained water to within practical limits. Itth'us occurs that I am able to make reinforced articles and synthetic leather by fluidic deposition of comminuted' substances, results which others have been unable to obtain owin to the high percentage of voids in the deposited material.

In obtaining the results stated, I use from 'aboutfifty pound gage pressure to above six hundred pounds gage pressure, depending upon the material.

It'will be seen that the 12 pounds or so pressure derivable from the atmosphere by ordinary air. exhausting apparatus is much too small to accomplish the necessary simultaiieous deposition and compacting of the and in accelerating the drying of. the sameby hastening the vaporization and escapement of contained moisture thereftom. V

In practicing m invention with liquid pulp, I find it pre erable'to introduce gaseous pressure before the excess pulp has been drained or discharged from the mold in order to avoid all danger that deposited ma terial may expand and absorb moisture while the mold is drainin or discharging and sometimes introduce tie gaseous pres sure before the pressure on the pulp has" been relaxed when workin with light material. However, I do not WlSh to limit myself to either of these procedures.

Also it ispreferable to introduce the gaseous pressure gradually so that the air or other gas may have full opportunity to vaporize the moisture in, the deposition, before the pressure becomes sutficient to cut down the flow by so compactin the deposition as to close the pores thereof. The vaporizing action of the gaseous medium in passing through the deposition is especially rapid when the medium is heated and also turned on gradually as above described, and I may use a wide range of temperature for this purpose, depending on the nature of the deposit-ed material. The temperature range of the gaseous medium may be from 140 degrees Fahrenheit up to above 600 Fahrenheit. r

I find that I can produce articles by my process which shall be ofpredetermined thickness and weight within exceedingly narrow limits, and believe I am the first to achieve these results when working With comminuted material, other than in the paper and board business.

I find, moreover, that it is not necessary to make a liquid containing pulp of the comminuted material as has always been the practice hitherto in depositing such material against a foraminous surface, but can de-. posit certain material in the mold While suspended in a gaseous current; consequently, I do not limit'myself to the use of a liquid containing pulp, but contemplate using my invention in connection with any convenient medium for depositing the comminuted material against the foraminous wall.

In carrying out my process, any suitable: apparatus may be used, but theapparatus shown and described in In prior applications Nos. 115,086, filed ugust' 15, 1916, and 165,185, filed April 28, 19 17, of which this application is a continuation, as being entirely suitable for this purpose.

Having thus described my invention I claim:

1. The processmf making articles from the mold to maintain-the comminuted material in position 011 the npold and to abstract a material percentage of the original moisture therefrom, andthe third step .of

whiclr consists; in increasing the pressure of I r v s i said gas to iurther compactthe deposited material.

2. :The process of n'iaking articles irom. comminuted material, the first step of WlllCh consists in simultaneously introducing pulp into aforaminous mold and depositing sai pulp under super-atmospheric pressure-to compact and form the wall of the article,

and the second 'step in thereafter introduc-- ing gaseous pressure to maintain the compactness' of and further compact the deposited material and to dry the sm le, said gaseouspressure being'relatively low at first for a material fraction of the time for making an article and being thereafter-increased.

3. The process of making article'sfrom comminuted material, which consists, in forcing a fluid mass against a foraminous mold under super-atmospheric pressure so as in one step to sin'iultaneously deliver,deposit and conipact the comminuted material in said mass, and in a second step to discharge the surplus comminuted material from the mold and introduce gaseous pressure to maintain the compactness of and further compact the deposited material prior to the completion of and as a concomitant operation with the discharging step, said gaseous pressure being relatively 'low at first for a material fraction .of the time for making an article and being thereafter increased.

.4. The process of making articles from comminuted material comprising forcing a fluid mass against a foraminous mold by super-atmospheric pressure on one side} of said mold and a partial vacuum on the other to simultaneously deposit and compact the comminuted material, and introducing gaseous pressure to maintain the compactness of the deposited material and to dry the same,

loo

said gaseous pressure being relatively low at first for a'material fraction ofthe time for making an article and being thereafter increased.

5. The process of making articles from comminuted material consisting in simultaneously delivering anchdepositing the material on the entire inner face of a foraminous mold, under an effective pressure of over forty pounds to deposit and compact the wall of the article at one step, and thereafter introducing gaseous pressure, said gaseous pressure being relatively low until a material percentage of the original moisture has been abstracted, and being. afterward increased. v

6. The process of making articles from comminuted material-consisting in simultaneously delivering and depositing the material on the entire inner face of a foraminous f stationary mold, under an efiectlve pressure of overforty pounds to deposit and compact the wall of the article at one step, and there- .7 after introducing gaseous pressure, said gaseous ressure being relatively low until a material percentage of the original moisture has been abstracted, and bein afterwardincreased to further compact tie wall of the article.

7. The process of making articles from comminuted material consisting in simultaneously delivering and depositing the material on a foraminous mold wall u-nder superatmosphe rie pressure to simultaneously deposit and compact the wall of the article, and

introdncingfgaseous pressure into the mold before relaxin the pressure of the com- 'minuted material, said gaseous presshre be- 7 ing relatively low at first for a material fraction ofthe time for making an article and being thereafter increased.

8. The process of making" articles from comminuted material, the first step of which consists in forcing a fluid mass'of said'material against all parts'of a foraminous mold ,wall at one ti'me'under-a pressure equivalent to over forty pounds ga e to simultaneousl deliver and deposit an compact the wal (of the article, and thereafter introducing gaseous pressure, said gaseous pressure being. maintained low to accelerate drying of the deposition until a material percentage of the original moisture has been removed from the deposition, the pressure being afterwardincreased to further compact the-wall ":of the article. I Y

9, The process of making articles from comminuted material, the first step of which consists in forcinga fluid mass under superatmospheric pressure against all parts of a foramlnous mold wall at one time to simul- 'taneously deliver to the mold and deposit and compact the comminuted material in said mass to form the wall .of the article, the second step of which consists in introducing gaseous pressure into the mold to maintain the compactness of the deposited material and to dry the same, and the third step of which consists in inc'reasin said gaseous pressure to further compact t e deposited material.

El e processof making articles from comminuted materiahthe first step of which fofaminous mold wall to deposit thereon the comm nuted material in said mass to form the wall of the article, the second step of"- treating elements while the exterior .wall of,

the article is subjected to apartial vacuum.

11. The process. of making articles from j comminuted material the first step of which consists in forcing a fluid Tmass under pressure against all parts of a foram'inous mold wall at one time to simultaneously deliverto the mold and deposit and compact the comminuted material insaid mass to form the wall of the article, and the second step of which consists in drying and'further compactingthe deposited material while inthe mold by a heated gaseous fluid under pressure while maintaining a artial' vacuum on the outlet'side of the mold?v 12. The rocess of making articles from comminute material the first step of which consists in forcing a fluid mass under pressure against all arts of a foraminous mold wall at one time tosimultaneously deliver and deposit and compact the comminuted material in said massto form ,the wall of i the article, the second step of which consists in drying and further compacting the deposited material by a heated gaseous fluid under pressure while maintaining a partial vacuum on the outlet side of the mold, and the third step ,ing the deposltion to treating material while the article is'still held in the mold.

F13. The process of making articles from comminuted material consisting in simulof which consists in subjecttaneously delivering and depositin the a material on the entire inner face of a oraminous mold under an efiective ressure of over, forty pounds gauge to deposit and com pact. the wall of the article in one step, and

thereafter introducing gaseous pr ssure,

said gaseous pressure being relativey low at first for a material fraction of time and being thereafter increased.

' HILLHOUSE BUEL.

00 cons1sts in forcing a fluid mass against a