When wood is seasoned with the help of chemical, it is termed as chemical seasoning. Overview of wood preservative chemicals ingredients used in. Seasoning is the process of removing the moisture content from wood to minimize structural problems when used in. This method is a quick process of seasoning the timber. Jul 30, 2018 it is then removed from the highpressure vessel and laid out to dry. Timber is an important construction material used widely for various engineering purposes. After seasoning has been done timber is not liable to be delayed. A wellseasoned timber contains moisture about 1012% of its dry weight. This document has been scanned from hardcopy archives for. The preliminary treatment by chemical seasoning ensures uniform seasoning of outer and inner parts of timber. Contents show reasons for timber seasoning method of timber seasoning 1. Several processes very satisfactory from the seasoning standpoint resulted from this work. The chromium acts as a chemical fixing agent and has little or no preserving properties.
Timber is to be seasoned well before application of preservatives. Timber has to be protected from the attack of insects, e. In this process, wood sleepers, planks and scantlings etc cut from the wood logs are stacked. A oily preservatives coaltar is the best known most widely used preservative obtained from bituminous coal available in many grades gives satisfactory results chemical seasoning of wood and preservation methods of application of preservatives. Seasoning of timber is done to fulfill some specific requirement. Factors affecting selection of construction materials. Oct 10, 2016 methodsmethods seasoning aims at drying a set quantity of timber uniformly to the equilibrium moisture content required with a minimum of degrade in the shortest possible time. The art of seasoning of timber is to extract the moisture under controlled conditions as nearly as possible at a uniform rate from all parts of timber and to leave the remaining moisture, that cannot be extracted. Different ways of seasoning wood home guides sf gate. Microwave seasoning uses pulsed energy directed into timbers to drive out moisture in a manner that will not cause seasoning degrade. In other words, seasoning of timber means getting rid of the sap and moisture from it. Then the timber is allowed to dry under a shed having free circulation of air. Shrinkage of timber all timber shrinks to some extent as it dries.
May 31, 2012 most parts of a house can be made from timber, if the type of timber is appropriate. In the development of the process many items of lumber were soaked or steeped in various water solutions including sodium chloride common house salt, monoammonium phosphate, zinc acetate, and several other chemical solutions. Seasoning is the process of removing the moisture content from wood to minimize structural problems when used in construction or to provide less. It is a process by which the amount of moisture in. A wellseasoned timber has 15% moisture content in it. By reducing moisture content, the strength, elasticity and durability properties are developed. Chemical seasoning chemical seasoning is used for highvalue applications where the timber is required to be completely free of surface checks e. Seasoning timber wood, water, air, seasoned, products. Most parts of a house can be made from timber, if the type of timber is appropriate. Artificial seasoning of timber seasoning by boiling. Generally, chemical seasoning includes storage of timber in a suitable salt solution for a certain period.
What is timber and what are various uses of timber. Timber treatment prevents deterioration by insect or fungal attack and preserves the quality of the timber. Seasoning is the name given to the methods of drying timber there are two methods by which timber can be dried. Avoiding the use of moist wood in construction projects is very important for a number of reasons, making this process key to the quality of timber builds of all types. This method is used for seasoning on a larger scale. There are two methods of seasoning of timber which are explained below. May 11, 2007 in some cases, microwave energy delivery can be combined with low ambient pressure to produce optimal seasoning speeds. Methodsmethods seasoning aims at drying a set quantity of timber uniformly to the equilibrium moisture content required with a minimum of degrade in the shortest possible time. Timber seasoning and chemical impregnation machine plant. Chemical seasoning as the name itself implies, this method employs chemicals for the seasoning of timber.
Seasoning of timber methods of timber seasoning ravi dhami. These treatments impregnate the wood cells, making them resistant to decay, insects, weather or fire. In this method, the timber is immersed in boiling water or exposed to the action of steam. Types of defects in timber as a construction material. There are many ways of seasoning or drying timber, but only two methods have been found satisfactory, principally for economic reasons. In other words, the timber or lumber is air dried for about one year. Timber classification, types, defects in timber civil. In this technique, in a solution of suitable salt the timber is immersed. The hot air is supplied from the discharging end so that temperature increase is gradual from charging end to discharging end. Dec 23, 2010 most parts of a house can be made from timber, if the type of timber is appropriate.
What is seasoning of timber type of seasoning of timber. Timber seasoning is a controlled process during which timber is allowed to dry out prior to being used in construction. Electrical seasoning seasoning of timber or simply timber seasoning is the process of drying timber or removing moisture or sap. Chemical salts like copper sulphate, mercury chloride and zinc chloride are used as preservative which can be dissolved in water to get liquid solution. The technique of airdrying consists mainly of making a stack. Followings are the reasons to perform timber seasoning. Seasoning of timber or drying of wood wood drying also seasoning lumber or wood seasoning reduces the moisture content of wood before its use. There are various types of defects in timber as a construction material. The wood spice process is the process by which the moisture in the wood is reduced to the required level by reducing the moisture content, strength, elasticity, and durability properties are developed. This technique is used for seasoning on a larger scale. Freshly felled timber contains moisture 100 to 200% of its dry weight. Seasoning of timber various method natural and aartificial. In this method timber is subjected to hot air in air. Newly felled tree contains a considerable quantity of sap.
Wood drying also seasoning lumber or wood seasoning reduces the moisture content of wood before its use. The amount of water thus contained varies with the kind of wood, the conditions under which it grew, and the season. However, by a correct understanding of the shrinkage of timber this effect can be mini mized, and timber can then be confidently used without fear of adverse behaviour subsequently in service. Apart from structural wood preservation measures, there are a number of different preservatives and processes also known as timber treatment, lumber treatment or pressure treatment that can extend the life of wood, timber, wood structures or engineered wood. In certain cases chemical treatment of the timber may be necessary. More than half the weight of freshly cut timber consists of moisture or sap. In other words seasoning of timber means getting rid of the sap and. Seasoning of timber is also achieved by boiling it in water for 3 to 4 hours. The term seasoning carries the meaning that the wood had been exposed to one or more seasons of weather.
In this method, the timber is immersed in a solution of suitable salt. Treated timber the types, hazard classes, alternatives. Timber is seasoned to dry out the timber to bring it to a usable and workable condition. In chemical seasoning carbon dioxide, ammonium carbonate or urea are used as agents for seasoning, those are applied in dry state, the inter surface of timber dries first than outer side. Seasoning with chemicals forest products laboratory.
Seasoning of timber artificial and natural methods. The preliminary treatment by chemical seasoning ensures uniform. Timber preserved by this method are used in piles in saltish water, poles, sleeper. Removal of moisture from timber so as to be in equilibrium with the moisture in surrounding atmospheric condition, where timber is likely to be used is called the seasoning of timber. This is as yet the most common process of seasoning used through the world.
Dec 16, 2014 timber treatment prevents deterioration by insect or fungal attack and preserves the quality of the timber. Timber can also be made fire proof to some extent by giving external coats and treatment of fire retarding chemicals like sodium silicate, sodium arsenate or borax. A boiler is used to produce steam for conventional steam heated kilns. Trees gives us the timber which is converted into required form and finally used. After the absorption of water by the solution logs are let to dry. In case of chemical seasoning, timber is stored in suitable salt solution.
They are odorless and do not generate flames when contact with fire. Timber seasoning and chemical impregnation machine plant, find complete details about timber seasoning and chemical impregnation machine plant,timber seasoning machine,timber season and chemical impregnation plant,timber impregnation plant from other woodworking machinery supplier or manufacturerhenan dafu mechanical import and export co. While, in the general scheme of seasoning, chemical seasoning promises to take its place with timehonored air drying and the more recent method of drying in a kiln, much more work will be required before its usefulness can be. Air drying airdrying is the drying of timber by exposing it to the air. If this sap is not removed the timber is likely to warp, crack and shrink. The following chemical wood preservatives are registered for treatment of lumber to be used in the residential lumber and timber market. In progressive kiln the carriages carrying timber travel from one end of kiln to other end gradually.
A sound and durable timber is a must for ensuring the structural stability and performance of the structure being constructed. In some cases, microwave energy delivery can be combined with low ambient pressure to produce optimal seasoning speeds. The salt solution used is such that it is capable of absorbing water from the timber. Types of these defects in timber is discussed in detail. The timber seasoned by this method becomes brittle and easy to break. Perfect seasoning is the most effective means of preservation. Reduction of moisture using salt solution is called chemical seasoning. Salts carried in volatile solvent other than water.
The different ways that seasoning in wood can be achieved. What are the is codes used for timber and timber stores. In this type, wood wastes are burnt and heat produced is directly used to warm air in the kiln. When wood is used as a construction material, whether as. These generally increase the durability and resistance from being destroyed by insects or fungus. Chemical seasoning is used for highvalue applications where the timber is required to be completely free of surface checks e. Dec 14, 2018 seasoning is the process of removing the moisture content from wood to minimize structural problems when used in construction or to provide less smoke and more uniform combustion when used as. It is then removed from the highpressure vessel and laid out to dry. Among the other methods of seasoning of timber and wood, the chemical seasoning and electric seasoning are of some importance. In the chemical seasoning of wood with aqueous solutions of hygroscopic organic chemicals the step which consists of incorporating a watersoluble chlorophenolate in the treating so. It fre quently happens that in the sapwood, and sometimes in the heart wood, the weight of the water is more than the weight of the wood substance itself. If you mean lumber or boards, the lumber needs to be stacked in a way.
Before the timber can be used a large part of the moisture must be removed. In this method the timber is cut in suitable sizes and immersed wholly in water, preferably in running water. While such treatments will add to the cost of the timber, they can significantly increase the timbers service life. Unfortunately, the chemicals that are used to preserve timber can also be harmful to people. Chemical seasoning of timber limited timber development association on. During this period the sap contained in wood is washed away.
If the timber is used indoors and not exposed directly to the weather, its moisture content from then on will fluctuate only a few per cent following changes in relative humidity. Oct 25, 2017 the term seasoning carries the meaning that the wood had been exposed to one or more seasons of weather. By reducing the moisture content, strength, elasticity, and durability properties are developed. The wood spice process is the process by which the moisture in the wood is reduced to the required level. By chemical seasoning ensures uniform seasoning of outer and inner parts of timber. Chemical seasoning of wood and preservation methods of. A range of different chemical treatments has been developed to enhance the durability and service life of timber. When timber has dried to this state, it is said to be at its equilibrium. Seasoning of timber and drying of wood types and methods. Dec 23, 2015 removal of moisture from timber so as to be in equilibrium with moisture in surrounding atmospheric condition, where timber is likely to be used is called as seasoning of timber. Timber its properties, classifications, parts, seasoning. Artificial seasoning of timber, civil engineering, assignment. Timber which is cut in the nongrowing time winter is more durable. The time required for this seasoning is 30 to 40 days.
When the drying is done in a kiln, the product is known as kilndried timber or lumber, whereas air drying is the more traditional method. Timber is also used in making various sports goods and musical instruments, as building blocks for ships, buses, and trains, for decorative purposes in homes and offices in the form of showcases and furniture. Precautions must be taken by anyone working with treated timber including those who carry out the treatment and those who work with treated timber. Preservation of timber means protecting timber from fungi and insects attack so that its life is increased. Timber should be so used that either it is wholly dry and well ventilated or is wholly under water. In this process, wood sleepers, planks and scantlings etc cut from the wood logs are stacked in open air. Seasoning of timber is the process by which moisture content in the timber is reduced to required level. Time required for natural seasoning of timber is around 120 to 180 days. Timber is also used in light construction works like doors, windows, flooring, roofing and fencing poles, electric poles and gates. Seasoning is the reduction of moisture content of timber to that of thesurrounding air sydney area approx.
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