US1936439A

US1936439A - Treatment of wood

Info

Publication number: US1936439A
Application number: US486718A
Authority: US
Inventors: Carl H Siever
Original assignee: Individual
Current assignee: Individual
Priority date: 1930-10-06
Filing date: 1930-10-06
Publication date: 1933-11-21
Anticipated expiration: 1950-11-21
Also published as: DE8911395U1

Description

Patented Nov. 21, '1933 UNITED STATES 'rnnamnr oF woon can n. siever, oak Puk, m, Application october s, 1930. serial Nu. 486,718

-2Claims.

My present invention relates to improvements in the treatment Vof wood and has to do particularly with method of and means for preventing the cracking of Wooden timbers.

i The treatment of wooden timbers such as railroad crossties and the like, to prolong the life thereof, is becoming of more and more impor'- tance as time goes on, and the supply of Wood diminishes. It is safe to assume that at least l@ 90% of the wood used for' railroad crossties is subjected to some kind of preservative treatment before it is used. With the best treatment available, the useful life of the crosstie is of course increased, but still it is only a matter of a few ld added years before the tie is permanently out of service.

One of the principal causes of the relatively rapid deterioration of wood, particularly heavy wood such as crossties, when used outside, is

2Q the cracking Ywhich takes place due to exposure to the weather and the like. nating treatment extends only a fraction of an inch, or an inch at most, below the surface, a crack not only admits water and causes a rapid deterioration in the tie from a mechanical standpoint, but it admits fungi to the central, untreated portions of the tie where relatively rapid propagation takes place, and the tie ,issoon rendered y unfit for use. Accordingly, if railroad ties and 3o similar wooden timbers are to be given a long useful life, they must be treated either to prevent cracking, or to cause such a thorough and deep impregnation that even though the wood does crack, no fertile field for the lodgment of fungi will be found.

The principal object of my present invention is to prevent the cracking of wooden timbers.

i Another, but incidental object, is to secure a more thorough impregnation of the wooden 4o timber. y

Another object is the production of a wooden member such as a crosstie which will have a long and useful life.

Other objects and features of the invention will be apparent from a consideration of the following detailed description taken with the accompanying drawing, wherein, j

Fig. 1 is a fragmentary sectional view showing a crosstie treated in accordance with my present invention, and,

Fig. 2 is a sectional view taken along the line 2--2 of Fig. 1.

Referring generally to the invention first, I prepare the tie by forming openings, preferably longitudinal and continuous openings, and then than from the interior.

Since the impregimpregnate the ties, including the area of the openings in the most approved fashion, andthis method when properlyl controlled, produces a tie which will not crack appreciably under the most l severe conditions. In order that those skilled in l0 the art may fully understand the invention, however, I shall describe the same in detail, including certain explanations which appear to clarify the situation, but by which I do not bind myself, as of course, the explanation for the behavior of the tie may be incorrect.

First, as to the reason for the cracking, it appears that when timber -which contains a relatively high percentage of/'moisture is subjected to a rapid drying process, moisture is driven from the surface thereof` a great deal more rapidly This causes a shrinking of the timber on the surface, thereby bringing `up strains and stresses which are relieved only by the fracturing of the-surface, resulting in a crack. It appears that this condition might be corrected by slow, controlled drying of the timber, but this is neither commercially practicable nor positive treatment. -It appears that by forming openings `through the timber and then impregn 'ating it, as carried out by me, an equilibrium is established which is not disturbed or. modied by subsequent conditions devolping in the timber during its useful life.

In the specific steps in carrying out my procese,

I select a standard type of tie, freshlycut, and

before cracking strains have been setup therein, and form a number of openings 10 therethrough,

vpreferably as shown in Fig. 1. These openings are shown as. five in number, but they may have any shape and distribution desired. In actual practice, ve round openings one-half inch in diameter and extending from one end to the other of the timber are adequate. l

The next step in the preferred c out of the process is `the further partial drying of the wood, which is preferably vcarried on to substantially what is known as the ber saturationv poin although the timber is not necesa sarily reduced to this state of dryness. I wish to point out here that as far as the drying of the timber is concerned, this may be varied within a considerable range, and all of the drying may take place before the holes are bored, and preferably, sorne should take place before the-boring A of the goles, particularly if the wood is unusually et. Those acquainted with the treatment and handling of wood will understand that the timberv should be dry `enough to make the boring of the holes a relatively simple matter,

but under no circumstances should the timber be so dry that cracking takes place.

After the boring of the holes and when the timber has reached its proper state of dryness, it is impregnated in such a Way as to expose the area of the openings to the impreginating liquid. In the preferred practice of the invention heat and pressure are used as now generally carried on in pressure tanks. I prefer the use of creosote for impregnation, or a mixture of creosote and other substances, as shown in my copending application, Serial Number 486,717,l led October 6, 1930. When the timber has been thoroughly impregnated, it is removed from the impregnating liquid, care being taken to keep the openings lled with the impregnating liquid. This is done preferably by corking up both ends of the opening. preferably with creosoted wooden plugs 1l which are driven into place and retained there during theentire life of the timber.

I have found that timbers treated in this way will not crack under the most extreme and rigorous tests. In order to compare the product produced by my process with timbers treated in other ways, I carried out the following experiments: v

First, I took tive sets of four timbers each and bored three sets of them as shown in the attached drawing. The rst drilled set was then further treated in accordance with the process outlined above, using hot creosote at pressure varying from 150 to 200 pounds for approximately five hours. The second set of four drilled Wooden pieces was treated in the same way, except that the openings or canals therethrough were impregnated with hot petroleum oil, from which the more volatile constituents had been removed. The third set of four drilled wooden pieces was left unplugged and treated in a hot creosote bath for ilve hours at atmospheric pressure and at a temperature of 180 degrees Fahrenheit. The fourth set of wooden pieces was undrilled but subjected to the same creosote treatment as the third set. The fifth set of undrilled pieces received no treatment whatsoever. As a test, all oi the samples were stored for a long period of time, two of each set of samples being rst soaked in water for a relatively long period of time, and then subsequently aged in the open. This included cold Winter weather with ice, etc., at which time considerable damage is always done to exposed Wood. Spikes were also driven through all of the wooden pieces in places to determine what eilect, if any, the presence of spikes would have upon the cracking of the timbers. v

At the end of the test period all of the undrilled wooden pieces, both dry and water soaked, were very badly cracked, the cracking in some cases extending entirely through the wood and substances.

passing through the spike holes. The water soaked pieces, however, were found to be cracked the worst. All of the drilled pieces which had been impregnated at atmospheric pressure showed cracks at the nail holes (the water soaked pieces being the worst) but no appreciable cracking in other places. None of the drilled samples which had been impregnated internally under pressure were cracked,` regardless of whether or not they had been previously Water soaked. This was true both of samples 1 and 2, namely, those treated with creosote and those treated internally with petroleum oil. It is obvious therefore, that the treatment by internal impregnation under pressure has a definite value in preventing cracking of wood when the latter is exposed to outdoor Weather conditions.

The cross-sectional view shown in Fig. 2 illustrates in general, the action of the impregnating substances. impregnation takesv place at the usual depth both on the side and surfaces of the openings, as shown by the shading in Fig. 2. When Water-proofing material such as creosote is sealed into the interior of the tie it gradually penetrates as time passes as shown by the light 10@ shaded portions, sothat ultimately, substantially complete impregnation therethrough results.

Those skilled in the art will understand that the details given above are illustrative, and that the invention may take other forms. For example, I am not limited to an particular number, size and shape of holes orcanals in the timbers, but may use any number which the size of the timber may require, and the size and cross shape of the holes may be varied. While I refer to wood 11@ in the claims, the process can be used on any cellulosic substances of vegetable origin, and the term wood is used broadly to include all of such As to the Wood treating material, this may be a waterproong substance alone, or it may contain added toxic substances, illustrated in my copending application referred to hereinabove.

What I claim is new and desire to protect by l Letters Patent of the United States is:- 12@ 1. The method of treating wooden timbers to prevent cracking thereof, which consists in forming canals in the timbers, drying the timbers, impregnating the timbers with a waterproofing liquid under heat and pressure, and then closing the ends of the canals to conne some of the liquid therein.

2. The method of treating wooden timbers to prevent cracking thereof, which consists in forming canals in the timbers, impregnating the timbers with creosote with heat and pressure, andsealing the ends of the canals so as to conne a portion of creosote therein.

CARL H. SIEVER..