1. The moisture in the wood includes free water, sorbed water, and combined water.we are provide HF wood dry machine,you can know it.

　　1. Free water is present in the large capillary system of wood. (This type is easily removed in wood drying and is the largest, for example, the free water content of Paulownia is up to 250%)

　　2. The sorption water is present in the microcapillary of the wood. The sorption water content of the wood of different tree species is 23-33%, with an average of 30%. Only when a certain amount of energy is obtained, the binding force of the microcapillary is overcome, and the water can be sucked from the wood. Discharged, so this type of moisture is not easy to rule out.

　　3, compound water exists in the chemical composition of wood, its content is about 1%, dry can not be removed, generally not considered.

　　Second, the concept commonly used in wood drying:

　　1. Moisture content: refers to the moisture content in the wood. The ratio of the weight of the moisture contained in the wood to the weight of the absolute dry material is called the absolute moisture content, referred to as the water content, expressed by W.

　　2. Electrical measurement method: A method for directly determining the water content based on the relationship between the electrical properties of wood and the water content. A commonly used resistive wood moisture meter is available.

　　3. Fiber saturation point of wood: The moisture content of wet wood in the presence of large free capillary water is completely evaporated, while the sorption water in the capillary system is still saturated with wood moisture content. (The junction of free water and absorbing water) The saturation point of wood fiber is the turning point of the material variation. The increase or decrease of absorbing water will cause the expansion and contraction of wood and affect the dimensional stability of wood products and other wood physics.

　　4, the equilibrium moisture content of wood: a piece of wood in a hot humid air for a period of time, the moisture in the wood and the moisture in the air are no longer exchanged to reach an equilibrium state of water content called the equilibrium water content in the air state.

　　The high-frequency vacuum wood dryer is a new type of wood drying equipment. It uses high-frequency drying to heat the wood inside and outside at the same time, heating evenly, drying fast and short time, and can maintain the natural color of the wood. At the same time, it has the advantages of low temperature and quick drying under vacuum conditions.

　　Suitable for mahogany, hardwood, thick, ultra-thin veneer and large-section square wood. Common precious woods such as rosewood, wenge, huanghuali, etc. It is also suitable for secondary drying after small batches and expedited wood returning to moisture.

　　High-frequency vacuum wood drying equipment is the perfect combination of high-frequency heating and vacuum dewatering.