RU2453426C1 - Method to pickle wood and device for its realisation - Google Patents

Abstract

FIELD: wood working industry.

SUBSTANCE: invention relates to a technology of industrial manufacturing of pickled wood and may be used in wood working, furniture and other industries when manufacturing and restoring items from hard-to-impregnate wood types. The method to pickle wood includes its preliminary drying, heating for 2-3 hours to the temperature of 200-240°C and soaking at these temperatures in a tight chamber filled with oil above the wood level. Oil is used with a flash temperature above the oil heating temperature. Soaking at these temperatures is carried out for 2-4 hr. Then oil is drained, vacuum of 20 kPa is pulled in the chamber, wood is cooled by steaming with vapour vapour and soaking under vacuum for 2-3 hours. The device to implement a method to pickle wood includes a tight chamber equipped with a heater. At the same time the chamber is additionally equipped with a blade mixer, a condenser, a vacuum pump and a reservoir to drain or store oil comprising an internal reservoir for water communicating with the help of a steam pipeline with a working cavity of the chamber.

EFFECT: invention makes it possible to produce pickled wood of hard-to-impregnate wood types with high decorative properties, even colour in thickness and with present colour up to coal black colour of a natural pickled oakwood.

3 cl, 2 dwg

Description

The invention relates to the technology for the industrial manufacture of stained wood and can be used in woodworking, furniture and other industries in the manufacture and restoration of products from hard-to-digest wood species.

There is a method of staining wood, including its thermochemical treatment in a hermetically sealed reactor with biuret vapors formed by heating crystalline biuret or urea powder at a temperature of 150-180 ° C and a pressure of 2-6 atm for 3-6 hours, see RU patent No. 2053874, IPC6 B27K 5/02, 1996.

The disadvantage of this method is that the wood is stained with chemicals, while the biuret used in the known method is expensive, and the urea during the staining process emits gaseous ammonia related to chemically active, explosive and harmful to human health substances, which reduces the environmental safety of the process of staining wood.

A known method of staining wood, including its heating in the chamber to 140-150 ° C, further heating of the wood in an atmosphere of water vapor at a temperature of 210-240 ° C for 30-60 minutes, stop self-heating using controlled water injection and cooling the wood in the atmosphere 100% supersaturated water vapor by controlled injection of water.

A device for implementing this method is a sealed chamber that is connected through ducts to a high-temperature thermal fan for pumping air and is equipped with an air heating unit containing air heating elements and control thermocouples, as well as an injection device for dosed water supply, see patent RU No. 2277045, IPC B27K 3/02, B27K 3/10, 2006.

The disadvantages of this method are the large cost of electricity due to the process in the environment of water vapor generated by evaporation of the injected water, and the cooling stage, also carried out by injection of water, does not allow the use of thermal energy of the heated material for other technological purposes.

The closest set of essential features is the method of wood staining, including heating the wood to a temperature of 50-110 ° C with holding for 1-15 hours, followed by heating at a temperature of 190-250 ° C for 1-3 hours in a sealed chamber filled oil above the level of wood, oil is used with a flash point above the heating temperature of the oil.

A device for implementing the known method of wood staining is a chamber equipped with a heater, an energy boiler, a heat exchanger filled with oil and communicating with a coil located in the chamber, as well as a pump for circulating oil through the channels of the heat exchanger and coil, see patent RU No. 2383433, IPC B27K 05/04, 2010.

The disadvantage of this method is that it does not provide a cooling stage, which leads to ignition during unloading of wood after the processing process at a temperature of 250 ° C or to a significant duration of the processing process during natural cooling of the material in oil. In addition, heating the oil with a temperature value of 50-110 ° C to a temperature of 190-250 ° C for 1-3 hours without an appropriate exposure stage does not allow achieving a uniform cross section of black color, which is especially important when simulating bog oak.

The objective of the invention is to provide a method for staining wood of hard-to-digest species and a device for its implementation in order to increase the productivity of the process by intensifying the cooling stage of treated wood.

The technical problem is solved by the method of wood staining, including its preliminary drying, heating for 2-3 hours to a temperature of 200-240 ° C and holding at these temperatures in a sealed chamber filled with oil above the wood level, the oil is used with a flash point above the oil heating temperature moreover, exposure at these temperatures is carried out for 2-4 hours, after which the oil is drained, a vacuum of 20 kPa is created in the chamber, then the wood is cooled by steaming with water vapor and exposure under vacuum for 2-3 hours s.

The technical problem is also solved by a device for implementing the method of wood staining, including a sealed chamber equipped with a heater, while the chamber is additionally equipped with a paddle mixer, a condenser, a vacuum pump and a tank for draining and storing oil, which includes an internal water tank communicating with the working pipe chamber cavity.

This method can be represented in the form of a graph of changes in pressure and temperature in the process of staining wood, see figure 1, and a diagram of a device for implementing the method of staining wood, see figure 2.

The invention is illustrated by the following specific embodiment.

The method of staining hard-to-impregnated wood, for example oak, with a moisture content of 8-12%, see Fig. 1, is carried out in a sealed chamber filled with oil (with a flash point above the heating temperature of the oil) above the level of the wood, which provides thermal energy immediately over the entire area of the material and contributes to an even distribution of the temperature and humidity of the wood, the wood is heated for 2-3 hours to a temperature of 200-240 ° C, after heating to a predetermined value and holding the material at this temperature for 2-4 hours, the oil is drained, A vacuum of 20 kPa is created in the chamber, after which the wood is steamed with water vapor, while maintaining the pressure in the chamber not higher than atmospheric value, then it is kept under vacuum for 2-3 hours.

The proposed device for staining wood, see figure 2, consists of a sealed chamber 1 and a flat lid 2 with a clamping metal partition 3. Inside the autoclave there is a thermoelectric heater 4, over which the wood 5 subjected to heat treatment, and a paddle mixer are placed 6. Installation also consists of a tank 7 for storing a hydrophobic liquid, a condenser 8, a vacuum pump 9, vacuum valves 10, 11 and an inlet valve 12. Moreover, the tank 7 for storing a hydrophobic liquid contains an internal tank 13, with communicating with the camera 1 using the steam line 14 with the valve 15.

The process of industrial production of bog oak is as follows. Through an open lid 2, wood 5 is placed in a sealed chamber 1. After sealing the autoclave using a vacuum pump 9 by pumping air from the apparatus with open valves 10, 11 and 16, the chamber is filled with liquid from the tank 7. After filling the autoclave with a sufficient amount of liquid, the valves 10, 11 and 16 are closed, include a thermoelectric heater 4 and a paddle mixer 6, which creates a fluid circulation. The liquid medium, and therefore the wood, is gradually heated to a temperature of 200-240 ° C for 2-3 hours at a pressure not exceeding atmospheric value. After increasing the temperature of wood 5 to a predetermined value, it is held in a liquid medium for 2-4 hours, depending on the species and thickness of the lumber. Upon reaching the required degree of staining, the liquid is drained from the chamber 1 into the tank 7 with the valves 12 and 16 open. At the same time, water is preliminarily added to the inner tank 13 of the tank 7 by opening the valve 17, which, as a result of the discharge of the heated liquid, boils with creating excess pressure in the reservoir 13. After draining all the fluid of the chamber 1 in the latter using a vacuum pump 9 and a condenser 8 with open valves 10 and 11 create a vacuum. Extract of wood 5 in a vacuum is carried out for 15-20 minutes Next, by opening the valve 15, water vapor is supplied from the reservoir 13 to the chamber 1, while the condenser 8 remains in operation, the valve 10 is closed. The flow of water vapor from the tank 13 and the capacity of the condenser 8 are selected so that the saturated steam entering the chamber 1, overheating from the heated material, is removed into the condenser 8 without creating excessive pressure in the autoclave 1, while the refrigerant heated in the condenser 8 can be used for technical purposes. After processing the wood 5 in a water vapor environment for 40-60 minutes, a vacuum is created in the chamber 1 using a vacuum pump 9 with the valves 10 and 11 open, where the wood 5 is held for 2–3 hours. After the cooling stage, the stained wood 5 is unloaded from the sealed chamber 1, where the raw wood is loaded, and the staining process is repeated using the liquid from the tank 7, cooled by heat exchange with water in the inner tank 13. The working fluid is cooled to subsequently uniformly warm the material.

The use of the stages of evacuation and steaming after heating the wood is aimed at lowering the temperature of the material to 120-130 ° C and at preventing the spontaneous combustion of wood at specified high temperature conditions, the use of the stage of final evacuation for 2-3 hours is aimed at cooling the material and eliminating the development of significant internal stresses and large residual deformations in the material, as well as the removal of a liquid processing agent from the internal cavities of wood cells.

The solution to the technical problem makes it possible to obtain stained wood of hard-to-digest species with high decorative properties, uniform coloring in thickness and with a given color scheme up to the bluish-black color of natural stained oak.

Claims (2)

1. The method of staining wood, including its preliminary drying, heating for 2-3 hours to a temperature of 200-240 ° C and holding at these temperatures in a sealed chamber filled with oil above the level of wood, the oil is used with a flash point above the temperature of heating the oil, characterized in that the exposure at these temperatures is carried out for 2-4 hours, after which the oil is drained, a vacuum of 20 kPa is created in the chamber, then the wood is cooled by steaming with steam and holding under vacuum for 2-3 hours. 2. A device for implementing the method of staining wood, comprising a sealed chamber equipped with a heater, characterized in that the chamber is additionally equipped with a paddle mixer, a condenser, a vacuum pump and a tank for draining and storing oil with an internal water tank communicating via a steam line with a working cavity cameras.