US1328655A - Process of drying lumber - Google Patents

Description

F. K. FISH, .ln. PROCESS OF DRYING LUMBER.

APPLICATION FILED APR.23. 1919.

Patented Jan. 20, 1920.

2 SHEETSSHEET I.

F. K. FISH, JR-

PROCESS OF DRYING LUMBER.

APPLICATION FILED APR.23. 1919.

1,328,655. Patented Ja11.20,1920.

2 SHEETS-SHEET 2.

avwentoz FREDERICK K. FISH, JR,, OF NEW YORK, N. Y.

PROCESS OF DRYING LUMBER.

Specification of Letters Patent. Patented Jan, 20, 1920,

- Application filed April 23, 1919. Serial No. 292,053.

' To all whom it may concern:

Be it known that I, FREDERICK K. F sn, J12, a cltizen ofthe United States of America, residing at 2 Stone street, New York.

city, in the county of New York and State of New York, have invented certain new and useful Improvements in Processes of Drying Lumber, ofwhich the following is a specification.

The present inventioin is based upon a proper recognition of the physical characteristics of wood structure, the chemical constituency of its fluid content, and has for its object the removal from the wood of those substances which, under natural con ditions, form the basis of its deterioration or destruction, and subsequently drying the wood.

structurally, wood consists of a skeleton of cellulose intermingled with other organic substances. collectively designated as lignin, together with a minor proportion of mineral matter or ash. Li nin, while not fully understood chemically, is closely allied to the cellulose element of the wood, and since it forms a part of the permanent structure ofthe wood, it may, for the purposes of the present invention, be regarded as identical with the cellulose.

I am aware, that for the obtaining of the objects above set forth, that wood has been subjected to steam with and without pres sure, thereafter drying the wood in kilns from which the accumulating moisture is withdrawn ..,continuously. I have found that by placing wood in a suitable container and surrounding it with a body of live steam under pressure while simultaneously sup plying dry heat to the interior of the container, that a much better and etlicient resuit is obtained, for the reason that the combined action of the dry heat and the live steam under pressure on the lumber is such that, while thesteam prevents the heat from too quickly drying the surface of the lumber, a condition which would prevent the penetration thereof by the steam, the dry heat raising the temperature of the lumber to such a degree as to prevent the condena satiou of the steam in the cells thereof by its suddenly coming in contact with "the cold condition which. has proven a seriousobjection to the process heretofore used, when steam, under pressure, is the treating medium.

-.It will be found that where wood is subjected to the combined action of live steam under pressure and dry heat, that the wood piece will become heated through and through and the steam and dry heat will penetrate to the center of the wood piece, the steam thereby coming in contact with the sap globules bursting them. Where dry heat is applied simultaneously with the .steam under pressure, the center of the wood piece will be brought to the same temperature as the surface thereof, causing evaporation from the center outwardly.

If wood is subjectedto a body of live steam under pressure without the accompanying action of dry heat, the steam, on

being forced into the cells of the wood piece, will become condensed therein, thereby adding to the already aqueous content of the wood, which will result in materially lengthening the time required for drying it thereafter. It is a well settled fact that'a comparatively small amount of heat will maintain a given temperature in a drying chamber when the aqueous content of the wood in such. chamber has been previously reduced, as compared with wood from which a portion of the aqueous content has not been previously reduced, so that the disadvantages of the condensing of the steam within the cells of the wood, thereby doubly loading it with aqueous matter, can be readily seen.

While if dry heatand live steam under pressure are simultaneously :applied, the wood is kept in a heated condlt on and the steam prevented from condensing 1n "the cells of the wood, and since steam has an the container 1, which-is then hermetically the same will be described with reference to the accompanying drawings, in which Figure 1 is avertical, longitudinal section of' a container, suitable for carrying out the first step of the process.

Fig. 2 is. a section taken on line ma Fig. 1.

Fig. 3 illustrates diagranm'iatically means for controlling the condition within the container.

Fig. 4 is a vertical, longitudinal section of a drying chamber.

Fig. 5 is a section taken on line bb Fig. 4.

eferringto the drawings more specifically, reference numeral 1 represents a container of construction suitable for containing steam under pressure, and is provided with a presser plate 2 with adjusting screws 3 through means of which the charge of wood may be kept under pressure to prevent warping while being treated. It is also provided with heating coils 4 by which the temperature of the atmosphere or steam within the container may be heated to the desired degree; and with pipes 5 which are perforated for the purpose of supplying live steam to the interior of the container when desired. 6 represents a. track to receive the car or truck upon which the wood is loaded for introduction into the container. 7 is a safety valve. pipe which is provided with valve 9 for controlling the pressure within the container 1 at will. 10 is a car upon which wood 11 is loaded for introduction into the container 1. 12 represents a boiler for generating steam and is connected to container 1 by pipe 13 which is supplied with a suitable va ve 14 for controlling the flow of steam into container 1.

Referring to Figs. 4 and 5, 15 represents the drying chamber which is provided with a pressure device 2, 3*, similar in structure to that employed in the container 1. 16 are heating pipes preferably located at the bottom of drying chamber 15 and are for the purpose of introducing dry heat thereinto. 17 is a traclnfor the convenient introduction into drying chamber 15 of a car load of wood and 18 is a stack which is provided with damper 19 and is for the purpose of removing from drying chamber 15 the accumulating moisture from around the wood at will.

In carrying out the process with the apparatus above described, av suitable charge of wood loaded on a truck is introduced into 8 is an escape closed and steam supplied through the spray pipe 5, and heat supplied through the operation of pipes 4.

To create the next step, the container 1 is opened and the load of wood is removed therefrom and transferred as rapidly as pos-' sible to the drying chamber 15, the load beingpreferably covered to minimize loss of heat during the transfer. Container 1 is now ready to repeat the first step of the process while the last step is being carried on in the drying chamber 15, said chamber being already heated is closed upon the load of Wood, the heating pipes 16 are operated sufficiently to keep up a temperature favorable to continuous evaporation of moisture from the wood, and the damper 19 in the stack is opened periodically tocreate a draft or current of air for carrying off the moisture as it accumulates, or may be kept applying dry heat; the final step brings about complete drying under conditions that evaporate remaining moisture at atmospheric pressure in a sufiiciently gradual manner to avoid taking the resin away from the wood structure.

What I claim is:

1. The process of drying lumber, which consists in subjecting the lumber to a body of live steam under pressure, while simultaneously applying dry heat, then subjecting the lumber to a body of dry heat While periodically removing the accumulating moisture from around the lumber.

2. The process of drying lumber, which consists in subjecting the'lumberto a body of live steam under pressure while simultaneously applying dry heat, then subjecting the lumber to a body of dry heat until dry, keeping the lumber under mechanical pressure during all the steps of the process. 3. The process of drying lumber, which consists in subjecting the lumber to a body of live steam under pressure while simultaneously applying dry heat, then subjecting the lumber to a body of dry heat while removing the accumulating moisture fromaround the lumber and keeping the lumber under mechanical pressure until dry. 7

4. The process of treating wood, which consists in producing in a retort-a body of free steam under pressure around the wood, while applying a dry heat to the wood, and then subjecting the wood to a dry heat while periodically. removing accumulating mois ture from said retort.

5. The process of treating Wood, which consists in producing around the wood while in a retort, a body of free steam under pressure, and then transferring the wood from said retort into an equalizing chamber and then subjecting thewood to dry heat while removing the accumulating moisture from the equalizing chamber.

6. The process of treating wood, which consists in producing around the wood while in a retort, a body of free steam under pressure and then transferring the wood while covered, from said retort, into an equalizing chamber and then subjecting the wood to dry heat while removing the accumulating moisture from the equalizing chamber.

7. The process of treating wood, which consists in producing around the wood while in a retort, a body of free steam under pressure, and then transferringthe wood from, said retort'into an equalizing chamber and then subjecting the wood to dry heat while removing the accumulating moisture from the equalizing chamber, the treatment being carried out while the wood isunder mechanical pressure. a

'- 8; The process of dryingjlu'mber, which consists in subjecting the lumber to a body of live steam under pressure while simultaneously applying dryheat, then transferring the lumber and while in transit preventing the escape 'of heat, and then subjecting the lumber to drying heat while periodically removing the accumulating moisture. I

- In testimony whereof I affix my signature.

- FREDERICK K; FISH JR.

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