US2205770A - Wood impregnation - Google Patents

Description

INVENTOR. aq/feml/aM//B f MQW ATTORNEYJV 3 Sheets-Sheet l HMUIWMI ,a .A and g m.. 4 w J L. R. VAN ALLEN WOOD IMPREGNATION Filed Nov. 11, 1937 nu n Llll June 25, 1940 Qlgl l L. R. VAN ALLEN 2,205,770

WOOD IMPREGNATION Filed Nov. ll, 1937 3 Sheets-Sheet 2 aff! Il INVENTOR.

ATTORNEY 3.

. June 25, 1940. R. VAN ALLEN 2,205,770

WOOD IMPREGNATION Filed Nov. l1, 1937 3 Sheets-Sheet 3 ATTORNEY I. 1I ULL wauw u ai" in ul- UNITED STATES PATENT OFFICE WOOD IMPREGNATION Lawrence R. van Allen, Chicago, Ill.

Application November 11, 1937, Serial No. 174,070

Claims.

This invention relates in general to wood impregnation, and more particularly to a process of blanching or bleaching or making more desirable the color of natural growth wood and timber by the use of reagents which have the combined function of presenting desirable impregnation characteristics and at the same time producing a sufficient evolution of gas when mixed together to build up an impregnating pressure.

A principal object of the invention is the provision of a novel method of bleaching natural growth wood or timber by displacing the natural saps and moisture of the wood structure from the log longitudinally thereof with gas or liquid under pressure, which gas and/or liquid will produce the desired decolorizing, blanching or bleaching effect in the interior and throughout the structure of the log or timber.

Another important object of the invention is the provision of novel apparatus for carrying out this method which is capable of use to selectively operate upon only certain desired portions of the log.

A further important object of the invention is the provision of apparatus for practicing the desired method which is so constructed as to facilitate reversal of the longitudinal flow of the liquid solutions and /or gases through the log from the original direction of flow without removing the log or changing its position in the apparatus.

Another important object of the invention is the provision of apparatus which permits the introduction of additional gas from an outside source of previously compressed gas to give added force to aid the progress of the solutions and /or gases into and through the capillary cells and bers of the log. It is contemplated that this additional gas may have the further value, in addition to that of supplying a supplemental impregnating force, of acting as a supplemental bleaching or color changing agent.

Another object of the invention is the provision of apparatus for practicing the instant method which is adapted to control the pressure at the outlet end of the log in a desired manner to assist in forcing the blanching or bleaching materials through the log.

A further important object of the invention is the elimination, reduction or minimizing of certain forms or deposits of a ferrous nature in the log which are objectionable and have heretofore been found to be incapable of eradication.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, when taken in connection with the accompanying drawings, disclose a preferred embodiment thereof.

In the drawings,

Figure 1 is an elevational view of the generating and charging portion of a preferred form of apparatus for practicing the instant method;

Figure 2 is an elevational view, partly in section, of the receiving or discharging portion of the apparatus of Fig. 1;

Figure 3 is an elevational View, with parts in section, of a modified form of the apparatus of Figs. 1 and 2;

Figure 4 is an elevational view of the outer end of one of the log end engaging or head members of Fig. 3; and

Figure 5 is an elevational View of the inner end of the head member of Fig. 4.

Referring more particularly to Figs. 1 and 2, reference numeral I I indicates a reaction or mixing chamber in the form of a tank of any suitable construction. Interconnected with the tank II and extending in opposite lateral directions therefrom, are a pair of pipes or conduits I2, to the outer ends of which are connected valves I3 of any desired construction. Extending upwardly from each of the valves I3, is a pipe I4 which is connected to the lower end of a tank I5, which functions as a receiving chamber. Adjacent the upper end of each of the tanks I5 is a receiving or charging unit I8, which comprises a substantially funnel-shaped member communicating with the tank I5 under the control of a suitable valve. The upper end of each of the tanks I5 is connected by piping I'I to the upper end of a tank I8 which functions as a gas chamber. A control valve I9 is interposed in each of the pipes I1.

The lower end of the gas chamber or tank I8 is interconnected with the upper end of the tank II by means of a pipe 2| having a control Valve 22 mounted therein. A relief valve, gauge and vent unit is mounted on the upper end of the gas chamber I8 which comprises a relief valve 23, gauge 24, vent 25 and valve 28 controlling communication between the latter and the tank I8.

The lower end of the tank II is provided with a pipe 2'I which extends downwardly to a suitable connection 28 and has a regulating valve 29 interposed therein. From the connection 28, a suitable conduit 3|, which is preferably in the form of a flexible connection, extends downwardly for a purpose to be later more fully described. One side of the connection 28 communicates with a gauge 32, while the other side is connected to a pipe or conduit 33 extending laterally therefrom. The conduit 33 has a valve 34 disposed therein and is connected at its other end to a suitable pipe fitting 35. A conduit 36 extends upwardly from the fitting 35 and is connected at its upper end with one of the pipes Il communicating with the gas chamber or tank I8. A valve 31 is interposed in the conduit 36 between the pipe Il and the fitting 35. The other side of the fitting 35 has a pipe or conduit connected thereto which is provided with a valve 39 adjacent the fitting 35.

The lower end of the exible connection 3| is provided with a short length of pipe 4| which is threaded into a suitable inlet aperture substantially centrally disposed in a log end engaging member or head member, indicated generally by reference numeral 42, and is adapted to be retained in engagement therewith by a suitable lock nut 43 (Fig. 2).

Referring more particularly to Fig. 2, the head member 42 comprises a substantially circular plate 44 having a recessed portion 45 provided in its bottom or inner surface Which is further recessed at its central portion at 46. A substantially circular plate 4l is disposed within the central recessed portion of the plate 44, and has a pair of bolts 48 swivelly connected at their lower ends thereto. The bolts 48 extend upwardly through suitable threaded apertures in the plate 44 and are provided with lock nuts 49 which are adapted to engage the upper surface of the plate 44 to retain the bolts in adjusted position. A cover member 5| may be provided for each of the bolts 48 which is adapted to frictionally engage its associated lock nut 49 in any suitable manner.

The head member 42 is adapted to be placed upon the upper end of a log 52 which is to be subjected to the instant blanching or bleaching process. For this purpose a circular gasket 53 is interposed between the adjustable plate member 4l and the end of the log, and a second compound gasket in the form of a ring 54 of cork or other suitable material, having a ring 55 of rubber or other suitable material disposed within an inner marginal recess therein, is interposed between the outer upper end of the log 52 and the recessed portion 45 of the plate 44.

A second log end engaging or head member, indicated generally by reference numeral 56, is provided which is substantially identical to the head member 42 and is adapted to engage the other or lower end of the log 52. Any suitable supporting means, such as a bracket or stand 51 may be employed for supporting the log 52 and the two head members 42 and 56. The lower head member 56 is'provided with the same recessed portions 45 and 46 in its upper surface as are provided in the lower surface of the head member 42. An adjustable plate 58, which is similar to the plate 47, is disposed within the central recess 46 of the head member 56 and is adapted to be positioned relative thereto by means of a bolt 59 which is threaded through a suitable aperture in the head member, and has a swivel connection with the plate 58 at its inner end. A combined cover and lock nut 6| is mounted on the outer end of the bolt 59, as shown in Fig. 2. Gaskets 53 and 54, 55, which are identical to those employed With the head member 42, are used in conjunction with the head member 56 for engaging the central and marginal lower end surfaces of the log 52. Each of the log end engaging or head members 56 and 42 is provided with a plurality of circumferentially spaced apertures 62 extending therethrough adjacent the marginal portions thereof. A plurality of tie rods or bolts 63 extend through associated apertures 62 in each of the head members, and are provided with suitable nuts 64 at one end thereof for the purpose of drawing the head members 42 and 56 towards each other and forcing them tightly into contact with their respective ends of the log 52.

A discharge pipe or conduit 65 is threaded into a suitable aperture in the lower log end engaging member 56 so as to communicate with the centrally disposed recess 46 in the upper surface thereof. The lower end of the pipe 65 is connected with a suitable tting 66, to the lower end of which is in turn connected a suitable drain valve 6l. A pipe or conduit 68 is also connected at one end to the fitting 66, and is connected at its other end to the upper portion of a tank or residuum receiver 69, preferably at one end thereof. A suitable control valve is interposed in the pipe or conduit 68. The tank or receiver 69 is mounted in any desired manner and is provided with a drain plug 'l2 in the lower portion thereof.

The lower end of the conduit 38 (referred to above in the description of the apparatus of Fig. l) is connected to one end of a pipe 74. The other end of the pipe 'I4 is connected to a suitable fitting l5 which communicates with the tank or receiver 69 by means of a pipe 16 that is interconnected between the two. A suitable pressure gauge 'll is connected to and mounted upon the fitting l5, and a pipe or conduit 'I6 is also connected at one end to the fitting. This conduit i8 is connected at its other end in any suitable manner with the discharge outlet of a rotary pump or compressor 19. The pump 'I9 is provided with the usual open ended air inlet 8|, and is adapted to be driven by an electric motor 82. The pump unit which comprises the pump 19 and motor 82 may be mounted upon the tank 19 in any suitable manner, as illustrated in Fig. 2.

In the use of the above described apparatus, the log 52 is mounted upon the lower log end engaging or head member 56, and the upper head member 42 is positioned upon the upper end of the log, as shown in Fig. 2, and tightly clamped in such position by means of the tie rods 63 and nuts 64. The desired bleaching or blanching solution is then fed into the upper head member 42 through the pipe 4|, and forced longitudinally through the log 52 into the lower or receiving head member 56, from which it flows into the receiving tank 69 through the conduits 65 and 68.

Any suitable penetrating and bleaching or preservative material may be employed which will produce the desired results. The preferred material comprises what will be designated as No. l and No. 2 solutions. The No. l solution is made up to include a catalytic agent, preferably of an alkaline nature, such as a suitable soda compound, ammonia, etc., and a penetrating and solvent liquid, such as glycerin, triethanolamne, etc. The purpose of the latter liquid is to dissolve the soluble part of the log structure, such as the resins, waxes, gambin, etc., normally found in the natural growth timber. After the timber has been cut into log form these materials will be crystallized in a relatively short period of time, and must be dissolved in order to be displaced from the log in the desired manner. The No. 2 solution comprises a bleaching agent, such as any suitable peroxide or the like, preferably strontium peroxide or barium peroxide.

In carrying out the instant method, the No. 1 solution is put into one of the tanks I5 of Fig. 1, while the other tank I5 is adapted to contain the No. 2 solution. With the valves I9 closed, the valves I3 are opened to permit the ow of the desired amounts and proportions of the two solutions from their respective tanks I5 into the mixing chamber II. The specific amounts of the two solutions employed will depend upon the size, age, condition and type of wood of the log 52 which is being treated. When the desired quantity of the two solutions have been admitted to the mixing chamber II, the valves I3 are closed. The catalytic agent in the No. 1 solution will react with the No. 2 solution to liberate gas, which will be oxygen in the case of the above recited preferred solutions. With these solutions, suiicient gas pressure will be developed to force the resulting mixture into and through the log 52 longitudinally thereof to dissolve the soluble part of the tree structure and displace it with the bleaching material, with the result that the log is bleached in the desired manner. Any excess of gas which may be developed in the mixture of the two solutions in the tank II may be allowed to flow into the gas chamber I8 by opening the valve 22. The residue which is dissolved from the log structure will be forced into the lower head member 56 and through the conduits 65 and 68 into the receiving tank 69.

It is to be understood that in the above described operation on the valves I9, 26, 34, 31, 39, 61 and 13 remain closed, while the valve 1I is open. The valve I3 is operated to control the ilow of the two solutions into the tank II in the desired manner. The valve 29 is operated to control the admission of the gases and solution to the upper head member 42, and the pressure characteristics of these gases and solution are indicated by the gauge 32. The valve 22 is operated, as above described, to permit any excess gas generated in the mixing chamber II to flow into the gas chamber I8, the pressure characteristics of which gas in the chamber I8 are indicated by the gauge 24. If it is desired, additional gas under pressure may be employed, where, for example, in some particular instance the gas generated by the solutions is insuicient, by connecting the pipe 25 to an outside source of gas, such as oxygen, under pressure. When such use is made of the apparatus, the valve 26 is adapted to be operated in accordance with the indications given by the gauge 24.

It has been found that in certain instances a cellular locking takes place within the log which prevents the flow of the gases and liquids through the log in the desired manner. This condition may be alleviated by employing the pump 19 to create a low pressure condition within the receiving tank 69. When such use of the pump 19 is made, the valve 13 is maintained in closed position, and the pressure within the tank is indicated by the gauge 11. If such cellular locking conditions persist, it may be found to be desirable to reverse the flow of the gases and bleaching or blanching solution through the log, from the lower end upwardly. This may be accomplished in the following manner: the valves 34, 39 and 13 are rst opened to permit the blanching or bleaching solution and gases to ow from the tank II down into the tank 69. It should be noted in this connection that additional gas may be supplied to the tank 69 as desired by closing the valve 34 and opening the valve 31. After the necessary liquid and gases have been admitted to the tank 69, these several valves, and in particular valve 13, are closed. The motor 82 is then started in a reverse direction to cause the pump 19 to force the gases and liquid in the tank 69 up through the conduits 68 and 65 into the lower head member 66, and from there upwardly through the log 52 longitudinally thereof. This same reverse direction of flow through the log may be obtained without the use of the auxiliary power of the pump 19 by closing the valve 29 after a sufficient supply of liquid has been admitted to the tank 69, closing the valve 34 and opening the valve 31. The gases generated in the mixing chamber II will then have a free path of flow through the tank I8 and conduits 36, 38, 14 and 16 into the tank 69 for the purpose of forcing the material therein upwardly through the log 52. 'I'he necessity for the reversal of flow of the materials through the log 52 will not frequently arise, but the instant apparatus is adapted for such operation if it is found to be necessary. i t

The purpose of the centrally disposed plates or clamping members 41 and 58 and their associated gaskets 53 is to prevent the access of the bleaching or blanching material, fluid and gases to the core or central part of the log 52. The reason for this is that this core portion of the log is generally not adapted for use in producing or cutting veneer from the log. It is clearly apparent, however, that these centrally disposed members 41 and 58 may be entirely dispensed with, if it is desired to treat the core portion of the log. By using strontium peroxide as the No. 2 solution above described, certain forms or deposits of a ferrous nature in the log which are objectionable and have heretofore been found to be incapable of eradication are readily eliminated, reduced or minimized.

With the above described method and apparatus, it will be apparent that natural growth wood or timber, especially in the log form, may be easily and readily bleached or blanched or have the color thereof made more desirable in a very effective manner. The equipment necessary is relatively very simple, and extensive handling of the log is completely eliminated. After the log has been treated in the manner described, it may be made into cut lumber or veneer in the usual and well-known manner. Subsequent surfacing or sanding of such cut lumber or veneer does not alter or destroy the appearance thereof, as is the case when a surface bleached piece of lumber or veneer is so resurfaced or sanded. The present method of impregnating the natural growth timber in the log form longitudinally of the log may also have advantageous application to treating the log in some manner other than bleaching, as by introducing insect or fungi toxic material therein.

The apparatus disclosed in Figs. 3, 4 and 5 is identical in function and substantially similar in construction to that of Figs. 1 and 2, with the primary exception of the log end engaging or head members. In this modification, the sam-e mixing tank or chamber II and receiving tank 69 are used, while a pump or compressor 83, which is similar in function to the pump 19, is interconnected with the remainder of the apparatus in the same manner as the latter. In this modification, the inlet pipe 4I of Figs. 1 and 2 is replaced by a flexible conduit 84 which is interconnected with the apparatus in the same manner as the pipe 4I, and is provided with a control valve adjacent the outer end thereof.

Similarly, a flexible conduit 86 is substituted for the rigid conduits 65, 68 of Figs. 1 and 2, which is in turn provided with a control valve 81 adjacent the end thereof. A second valve 88 may also be provided in the conduit 86 which is similar to the valve 6l shown in Fig. 2. The ends of the two flexible conduits 84 and 89 are adapted to be threaded into a selected tapped aperture 89 in a respective log end engaging or head member indicated generally by reference numeral 9|. The two head members 9| for engaging the opposite ends of the log 52, as shown in Fig. 3, are substantially identical in construction.

Each of the head members 9| comprises a substantially rectangular frame 92 which is made of any suitable material and in any desired manner. Secured to this frame 92, as by means of bolts 93, is a circular plate member 94. The inner surface of the plate member 94 (Figs. 3 and is provided with a plurality of concentrically disposed, annular recesses or grooves 95. The tapped apertures 89, above referred to, extend through the plate 94 and are so spaced and disposed relative to each other and the grooves 95 as to each communicate with a particular and separate groove. This arrangement of the tapped apertures 89 is best illustrated in Fig. 5. It is intended to use only a selected one of the several apertures 89 at any one time, so that the remainder of these apertures are normally closed by suitable plugs or bolts 96 (Fig. Ll). A threaded spike or pointed bolt 91 extends through a suitable tapped aperture in the center of the plate 94 and is provided with a suitable lock nut 98. The spike 9i is adapted to be embedded in the end of the log 52 for the purpose of centrally locating the head member 9| relative to the end of the log and initially retaining it thereon.

One of the head members 9| (that shown to the right in Fig. 3) is provided with a plurality of bolts 99 having VU-shaped heads which are pivotally connected to the frame member 92 by means of suitable pins |9| The other head member 9| is adapted to be adjustably connected to a plurality of tie rods |92 by means of removable pins |93, which are journaled in the frame 92 thereof and may be selectively positioned within any one of a plurality of longitudinally spaced apertures |94 in the associated tie rod |92. The other end of each of the tie rods |92 is threaded at 95 for engagement by a turn buckle |96 which is also adapted to engage the threaded end of the associated bolt 99. In this manner, the two head members 9| may be drawn tightly into engagement with their respective ends of the log 52 regardless of the particular length of the individual log being treated. In this modied form of the apparatus, the log 52 is mounted in a horizontal position on a pair of suitable brackets or stand members |97, as shown in Fig. 3.

The purpose of the annular grooves 5 and the plurality of tapped apertures 89 communicating therewith is to provide for the treatment of any selected annular portion of the log 52. For this purpose an outer annular gasket |98 of the desired diameter is disposed between each of the head members 9| and its associated end of the log 52 (as shown in Fig. 3) and a circular gasket |99 of any desired diameter is interposed between the central portion of each of the plates 94 and the end of the log. By using gaskets |98 and |99 of the correct diameter and width, any one or more of the annular grooves 95 may be exposed to pro vide a recess between the end of the log and the plate 94 of a width equal to that of the portion of the log which it is desired to treat. The charging' conduit 84 and the receiving or discharge conduit 89 may then be screwed into that one of the tapped apertures 89 which communicates with the recess thus provided between the associated plate 94 and the end of the log. The remaining apertures 89 are intended to be closed by means of the plugs 96.

The operation of this modied construction of the apparatus is identical to that of the construction disclosed in Figs. 1 and 2, the only difference being that any annular portion of the log 52 may be treated by selecting gaskets of the proper dimensions. The apparatus of both of the modications above described permits economical and rapid treatment of logs in the desired manner, is cheap and easy to manufacture, may be readily transported from place to place and does not require elaborate housing or auxiliary equipment. It will be understood that the head members 42 and 56 of the modication of Figs. 1 and 2 and the plates 94 of Figs. 3 to 5 may be given any desired shape other than the circular form herein disclosed, so that they will substantially conform to the cross sectional shape of any piece of wood which it is desired to treat in the manner above described.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the steps and their order of accomplishment of the process described, and in the form, construction and arrangement of the parts of the apparatus, without departing from the spirit and scope of the invention or sacriiicing all of its material advantages, the process and apparatus hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A method of bleaching wood which comprises treating the wood in the log form by displacing the natural soluble material in the log by forcing a solvent for such material longitudinally through the log and at the same time replacing the natural soluble material with bleaching material.

2. The method of impregnating a log with a bleaching material which comprises mixing the bleaching material with a solvent for the natural soluble material in the log and a catalytic agent for causing gas to be evolved from the bleaching material and confining the resulting mixture so that the gas thus evolved will force the solvent and the bleaching material together longitudinally through the log to displace the natural soluble material in the log and replace the same with the bleaching material.

3. The method of bleaching natural growth timber, comprising mixing a solution made up of a catalytic agent and a penetrating liquid which is a solvent for the natural soluble material in the wood and a solution which comprises a bleaching agent which will generate gas upon mixture with such catalytic agent, confining such mixture of said solutions to retain the generated gas under pressure, and introducing the resulting mixed solutions and gas to one end of a log together so that said solvent will dissolve the natural soluble material in the log and said gas will displace the latter longitudinaly from the log and replace it with said bleaching material.

4. The method of bleaching natural growth timber, comprising mixing a solution made up of a catalytic agent and a penetrating liquid which 75.

is a solvent for the natural soluble material in the wood and a solution which comprises a bleaching agent Which will generate gas upon mixture With such catalytic agent, confining such mixture of said solutions to retain the generated gas under pressure, introducing the resulting mixed solutions and gas to one end of a log together so that said solvent Will dissolve the natural soluble material in the log and said gas will displace the latter longitudinaly from the log and replace it with said bleaching material, and creating a lower than atmospheric pressure at the other end of the log.

5. A device for impregnating a log with a bleaching material, comprising means for mixing a solution comprising a catalytic agent and a earen solvent for the natural soluble matter in the log and a solution comprising a bleaching agent adapted to generate gas upon mixture with said catalytic agent, said means being adapted to confine the resulting mixture of the solutions and the gas so generated, means for conveying the resulting mixture and gas to one end of a log so that the gas will force' the solution through said log longitudinally thereof, meansl disposed at the other end of the log for receiving the material so forced therethrough, and means for optionally introducing additional gas under pressure with said resulting mixture and gas to the end of the log.

LAWRENCE R. VAN ALLEN.

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