RU2353873C2 - Installation for wood drying - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: installation for wood drying comprises cylindrical sealed body with the following components installed inside - heaters, fans and longitudinal partitions forming aerodynamic motion route, vacuum pump, steam generator and load trolley for placement of dried wood inside chamber. Installation is supplemented with the second similar chamber, two condensers and condensation equipment comprising compressor station, two heat exchangers for coolant heating and condenser cooling agent cooling, and additional heater, with the help of which heat energy removed from the first chamber, in which vacuumisation process is carried out, is supplied to the other chamber, in which dried saw timber is heated; on completion of heating-vacuumisation cycle, stages are changed in chambers by isolation of appropriate taps in pipelines: heating starts in the first chamber, and vacuumisation starts in the second one.

EFFECT: reduced prime cost of saw timber drying process.

1 dwg

Description

The present invention relates to techniques for drying lumber and may find application in forestry, woodworking and other industries.

A known installation for drying lumber in stacks, including a drying chamber, connected via pipelines with quick valves with a receiver and a vacuum pump. The installation along the length of the drying chamber is equipped with a series of sections formed by fans, air heaters and air ducts mounted outside the drying chamber, and the air ducts for pumping out steam and the resulting vapor-air mixture into the chamber are looped through the fan and air heater of each section separately (see the application RF patent No. 2003113179, IPC F26B 9/06, 2004).

The disadvantage of this dryer is the presence of a vacuum receiver, which leads to a significant increase in the cost of the drying chamber by increasing the number of vacuum equipment.

Also known is a wood drying apparatus, which consists of a sealed cylindrical body, a drying chamber, heaters, a fan and a vacuum pump (see RF patent No. 2156934, IPC F26B 9/06, 5/04, 2000).

The main disadvantage of this installation is the lack of a capacitor, which leads to an increase in energy consumption for the drying process of lumber due to the constant operation of a high-power vacuum pump.

Closest to the technical nature of the invention is an installation for drying wood, containing the upper and side sections made of elastic material in the form of membranes with the ability to change their size and shape under the influence of the coolant flow. The lower section has longitudinal slots, allowing you to place the dried lumber on a cargo trolley inside the drying chamber. In this chamber, a vacuum-convection drying method is implemented, the essence of which is the alternation of the stages of heating the dried wood and evacuation (see RF patent No. 2206843, MKI F26B 9/06, 2003).

The main disadvantage of this installation is the irrational use of resources due to the high cost of drying due to the independent cooling of the condenser and the independent heating of the heaters.

The aim of the present invention is to reduce the cost of the drying process of lumber.

This goal is achieved in that the installation comprising a cylindrical sealed enclosure with inside heaters, a fan and longitudinal partitions forming an aerodynamic path of movement, a vacuum pump, a steam generator and a trolley for placing dried wood inside the chamber, is characterized in that the installation is supplemented by a second similar a chamber, two condensers and condensing equipment, including a compressor station, two heat exchangers for heating the coolant and cooling the coolant condenser dagent, and an additional heater.

A distinctive feature of the claimed invention is that the installation is supplemented by a second similar chamber, two condensers and condensing equipment, including a compressor station, two heat exchangers for heating the coolant and cooling the condenser refrigerant, and an additional heater.

The process of transferring thermal energy from one chamber to another with the help of condensation equipment consumes less energy than the amount of energy transferred, therefore, the process of heating the sawn timber proceeds at lower energy costs. In addition, the installation of condensing equipment avoids the additional cost of cooling the refrigerant for the condenser.

The installation diagram is presented in the drawing.

The installation contains two similar vacuum chambers 1 and 2 with condensers 3 and 4 installed in the upper part, a steam generator 5, condensing equipment 6, including a compressor station 7, heat exchangers 8 and 9, liquid pumps 10 and 11. Compressor station 7 uses refrigerant as a refrigerant . To accelerate the process of heating the vacuum chamber at the starting time, an additional electric heater 12 is used to heat the oil heaters 13 and 14.

Installation of vacuum drying works as follows. After the formation of the stack of lumber 15 on the trolley and loading of one of the chambers 1, the stage of heating the dried wood begins, for this, the electric heater 12 is turned on and valves 16, 17 are opened when the liquid pump 10 is turned on. In parallel, the second chamber 2 is loaded. After the warming up of the stack 15 in the first chamber 1, by opening the valve 18 and turning on the vacuum pump 19 and supplying refrigerant to the condenser 3, the evacuation stage begins. Cooling of the refrigerant for the condenser 3 occurs when the valves 20 and 21 are open by transferring thermal energy to the refrigerant in the heat exchanger 8 using the pump 11. Next, the thermal energy removed from the first chamber 1 is transferred to the oil coolant 14 to heat the lumber using the compressor station 7 and heat exchanger 8 in the second chamber 2, for this, the valves 22 and 23 are open and the valves 16, 17 are closed. After the cycle is completed, the valves 18, 20, 21, 22, 23 are closed on the pipelines and the valves 24, 25, 26, 16, 17 are opened, the stages change in cameras: in the first heating begins in the chamber, and in the second - evacuation. If it is necessary to increase the heating intensity of the drying agent, an additional electric heater 12 is briefly turned on. When internal stresses occur, heat and heat treatment is performed by turning on the steam generator 5 and opening the valve 27 or 28 corresponding to the chamber.

The alternation of the stages of heating and evacuation in vacuum chambers occurs until the moisture content of the sawn timber decreases to a predetermined value (6-8%).

The advantages of the proposed installation are characterized by the following specific example of its implementation.

Overall dimensions of installation, mm:

L × W × H 8000 × 8200 × 3000 Fan motor power 7.7 kW Vacuum Pump Motor Power 7.5 kW Compressor unit power at maximum load (transmission 50 kW / h) 16 kW Power heaters 50 kW Steam generator power 30 kW

The table shows that for the transfer of thermal energy of 50 kW / h, the compressor unit takes 16 kW / h, allowing to reduce the total energy consumption for the drying process by more than two times.

The developed installation was accepted for implementation at CJSC Laskraft for drying valuable wood species.

Claims (1)

A wood drying apparatus, comprising a cylindrical sealed enclosure with inside heaters, a fan and longitudinal partitions forming an aerodynamic path of movement, a vacuum pump, a steam generator and a trolley for placing the dried wood inside the chamber, characterized in that the installation is supplemented by a second similar chamber, two condensers and condensing equipment, including a compressor station, two heat exchangers for heating the coolant and cooling the refrigerant conde nsator, and additional heater.