The Rueping Process. Latest Thing in Timber Preservation.

Progress, Volume IV, Issue 5, 1 March 1909, Page 163

The Rueping Process. Latest Thing in Timber Preservation.

INTRODUCTION. The value imparted to all timbers by the addition of creosote is incalculable. With-

out creosote only a percentage of milling timber is worth anything. With creosote added, the poorest timbers become strong and durable, with a resisting power proof against climates and insects alike, assured against the summer's sun and the winter's frost, certain never to rot before they die from natural causes. Under the old methods the creosote was overcharged, with two results, (1) the timber was not durable, and, (2), it was sodden, heavy and expensive. The reason it was not durable was that water getting into the pores, took away the creosote in them, and in due course, the rest of the creosote "leached" away as the timber men have it, after the first disturbance. But it mattered little whether the timber was durable or otherwise. The second of the above results of the old process made it too costly. So much creosote was absorbed

or substance that may be desired, and, secondly, to expel all the superfluous creosote. Put another way, its object is to reduce the required quantity of creosote to economic proportions, and at the same time to improve the quality and desirableness of the timber for use. This process is the property of C. Lembecke and Company, of ISiew York, who do business in the States, Canada and Mexico. Their representative in New Zealand is Mr. H. Lightband, to whom we are indebted for the particulars of this new process, which has restored the creosotnig of timber to the region of things practically economical. In most timbers the heartwood cannot be permeated with any liquid preservative without destroying the fibre of the heartwood, which, of course, would be unwise to do, as the heartwood in itself has generally strong resistant power against decay. As an average, timber to be impregnated has about forty per cent, hardwood. Thus of every cubic toot six-tenths, speaking roughly, contain matter to be impregnated against decay. More than fifty per cent, of tnis big proportion consists of air space, leaving a Dalance of less than fifty per cent., say about three-tenths of a cubic foot of wood fibre to be permeated with the preservative. Three-tenths of a cubic foot has a displacement equal to about 2.25 gallons. The Rueping Process leaves in the timber on an average 4% to 51bs. of creosote, equal to about % gallon per cubic foot. It will therefore be seen that the amount of preservative left in the timber is equal to at least twenty per cent, of the wood fibre, or tissue, to be preserved. This very high percentage, it will be understood, if creosote of good quality is to be used, will be amply sufficient to lastingly preserve the timber. The claim of the owners of the process is simple and clear. The principal object of the Rueping process is to make the impregnation of wood possible with such means of impregnation as have proved to be practically the best, but which, on account of their high price, could not up to the present time be used at all or in a very restricted manner only. Therefore the Rueping process is of very great importance to the tar-oil impregnation, because the latter used to be too expensive when carried out after the systems heretofore used. The Rueping process is also important for the impregnation with salt solutions, because with this new process considerably less of the impregnating fluid is required. Consequently it is possible to. use a more concentrated solution without increasing the cost of the impregnation. The more concentrated the salt solution, the stronger and longer lasting will be its effect. The small consumption of such solutions has, moreover, the great advantage that the wood impregnated after the Rueping process contains only a comparatively small quantity of water, in consequence of which only a short time is required for drying it, whereas with the full impregnation the wood must lie for months in order to become quite dry. For this reason very often wood is used, which is not yet sufficiently seasoned, a practice much to be deprecated, especially for railway ties. The latter, when laid on the track and imbedded in gravel, require a rather long time to become perfectly dry again, owing to the "hygroscopic" properties of most salts, especially chloride of zinc. If, however, the fibres of the wood are too long exposed

to the influence of salt solutions, a slow chemical destruction of the wood will take place.

The Modus operandi. The impregnating works consist principally of: 1. Impregnating cylinders strong enough for a pressure of from 7-15 atmospheres equal to 105-226 lbs. 2. A tar-oil tank capable of a pressure of from 5 to 8 atmospheres, equal to 75 to 1201bs. 3. An air compressor, which at the same time may serve as a vacuum pump. 4. A pressure pump. 5. A steam boiler. The cost is according to the amount of work to be done, and at the same time dependant on the local prices for boilers and machinery. The wood to be impregnated should be air-dry just as with the old systems of boiler-impregnation; it should therefore not contain more than about 20 per cent, of water. It can also be dried artificially, which, however, is not to be recommended on account of the additional cost thereby incurred. Of course the wood can be rafted on the way to the impregnating works. The best material for impregnating with has been long the subject of discussion. This firm has been led by its experiments to prefer creosote and discard all salt solutions.

Results of the Process. In the United States of America ten million sleepers are used every year, all creosoted by the Rueping process. That is a solid fact in corroDoration of this company's claims. Professor Tubeuf, of New York, easily recognised as the scientific authority on timber, thus reports a searching test of the behaviour of this timber in presence of the domestic fungus: — ■ "The boards impregnated after the Rueping process were put between boards infected by the domestic fungus, after they and all other wood in the cellar had been several times freely sprinkled with water. While wood not impregnated was destroyed in such a manner that it could be crushed to dust by the hand, the Rueping boards remained in the cellar for two years, exposed continuously to the infection of the fungi prolincally sprouting and growing all around them without thereby having been infected. The fungusmycel did not even grow on the surface of the Rueping boards, so that the boards after two years are exactly as intact as they were before the commencement of the test. It even appears that the exhalation of the creosote alone i.s injurious to the fungus and repulses its growth. If the domestic fungus does nol attack such boards, it is much less to be supposed that any other wood-destroying fungi will do so. ' ' There is, moreover, the important fact that on certain railways in France, within a period of 21 years, only 6 per cent, out of all the beechwood railway ties, which had been impregnated with tar-oil, had to be exchanged. This is because instead ot being gradually washed out of the wood by ram, tar-oil of proper quality, in the course of time becomes more and more solidified and covers the cell walls with a coating quite impervious to water and rain. By this means the solidity of the wood win gradually be increased and the mechanical wear considerably diminished. The case for creosote and the Rueping process is remarkably good.

Pait of longitudinal section cut from centre of Loblolly Tie after Eueping Process. by the sodden stuff, that the cost of the process became prohibitive. Therefore, when a new process was discovered ending this state of things, the creosote industry had been ended by the prohibitive cost of the creosoting. The remedy was very simple. Object of the rueping Process. The object of the new process, with the above name, is first to charge the timber thoroughly with creosote, or any other oil