RU2425306C1 - Wood drying plant - Google Patents

Abstract

FIELD: wood working industry.

SUBSTANCE: plant for wood drying comprises two vacuum chambers with installed heaters, fans, longitudinal partitions, which create an aerodynamical track of motion, a steam generator and a load trolley to locate dried wood inside the chamber. Vacuum chambers of the plant are complemented with steam ejectors connected to the steam generator, and their suction line is connected to an adjacent chamber, and heaters installed inside act as condensers of steam used by ejectors. Using steam ejectors makes it possible to simultaneously vacuumise in one chamber and heat in the other one. Besides, the thermal energy removed at the vacuumisation stage from one chamber is sent to heat saw timber in the other chamber.

EFFECT: reduction of prime cost of saw timber drying process, formation of steam in the steam generator may take place by combustion of wood waste generated in production.

1 tbl, 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 wood, including two drying chambers connected via pipelines with quick valves with a receiver and a vacuum pump. The volume receiver is equal to the free volume of one drying chamber after filling it with wood, equipped with a lock chamber and connected to it by a pipeline and valve. The pipelines connecting the drying chambers to the receiver are installed tangentially with respect to the receiver (see RF application No. 2002105237, MKI F26B 5/04, 2003).

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.

A wood drying apparatus is also known, which consists of a sealed cylindrical body with a lid, a steam generator, a drying chamber formed by the upper and side sections of elastic material in the form of membranes. The lateral surface is four-sectional, and the bottom has longitudinal slots that allow you to place the dried lumber on a cargo trolley inside the drying chamber (see RF patent No. 2206843, MKI F26B 9/06, 2003).

The main disadvantage of this installation is the inefficient 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.

Closest to the technical nature of the invention is a wood drying apparatus comprising a cylindrical sealed enclosure with inside heaters, a fan and longitudinal baffles forming an aerodynamic path of movement, a vacuum pump, a steam generator and a trolley for placing dried wood inside the chamber. The installation is equipped with two vacuum chambers, two condensers, additional heaters and condensing equipment, including a compressor station, two heat exchangers for heating the coolant and cooling the condenser refrigerant (see RF patent No. 2353873, IPC F26B 9/06, 5/04, 2008).

The main disadvantage of this installation is the use of complex and expensive condensing equipment and the cost of expensive electricity.

The aim of the present invention is to reduce the cost of drying lumber by reducing energy consumption and the possibility of using spent steam or other fuels as an energy carrier, as well as simplifying the design of drying equipment.

This goal is achieved in that the installation for drying wood, containing two vacuum chambers installed inside the heaters, fans, longitudinal partitions, forming an aerodynamic path of movement, a steam generator and a trolley for placing the dried wood inside the chamber, characterized in that the vacuum chambers are supplemented by connected with steam ejectors with a steam generator, the suction line of which is connected to an adjacent chamber, and the heaters installed inside act as condensers annogo steam ejectors.

A distinctive feature of the claimed invention is that the vacuum chambers are supplemented with steam ejectors connected to the steam generator, the suction line of which is connected to the adjacent chamber, and the heaters installed inside play the role of condensers used by steam ejectors.

The use of steam ejectors allows simultaneous evacuation in one chamber and heating in another. In addition, the thermal energy removed at the stage of evacuation from one chamber is transferred to heat pilomatermals in another chamber.

The installation diagram is presented in the drawing.

The installation contains two similar vacuum chambers 1 and 2 with inside heaters 3 and 4 and fans 5 and 6, a steam generator 7, steam ejectors 8 and 9, a water pump 10. At the bottom of the installation there are steam traps 11 and 12.

Installation of vacuum drying works as follows. After the formation of a stack of lumber 13 on a cargo trolley and loading it into the chamber 1, the stage of heating the dried wood begins. To do this, turn on the steam generator 7 and open the valve 14 for supplying steam to the ejector 8. The steam after passing through the ejector 8 enters the air heater 3, where, by condensing, it transfers thermal energy to the drying agent in the chamber 1. The waste steam in the form of condensate is removed through a steam trap 11. In parallel lumber is being loaded into chamber 2.

After the warming up of the stack 13 in the first chamber 1, the evacuation stage begins. To do this, close the valve 14, open the valves 15, 16 to supply steam to the ejector 9. In this case, in the chamber 2, by turning on the fan 6, the heating stage begins. Condensate through the steam traps 11 and 12, open taps 18, 19 and when the pump 10 is turned on, enters the steam generator 7 for further evaporation and use in the process. Excess condensate is discharged into the sewer through valve 20.

After the end of the cycle, by shutting off the taps 15 and 16 and opening 14 and 17, the stages in the chambers change: in chamber 1, heating starts again, and in chamber 2, evacuation begins. The alternation of the stages of heating and evacuation in the chambers occurs until the moisture content of the lumber decreases to a predetermined value (6-8%).

The advantages of the proposed installation are shown by comparing it with a prototype.

Characteristic Prototype Suggested installation Overall dimensions of the installation L × W × H, mm 8000 × 8200 × 3000 8000 × 6900 × 3150 Fan motor power, kW 7.7 7.7 Power of the electric motor of the vacuum pump, kW 7.5 - Power of the electric motor of the water pump, kW - 0.5 Power of the compressor unit at maximum load (at transmission 50 kW / h), kW 16 - Power of heaters, kW fifty fifty Steam generator power, kW thirty fifty The possibility of using exhaust steam and woodworking waste to produce thermal energy absent is available

The table shows that with the overall approximately equal capacities of the equipment used, the proposed installation does not have expensive compressor equipment and a vacuum pump, and the necessary power of the steam generator can be achieved by using a cheap energy carrier - spent steam or by operating the steam generator on wood processing waste. In this regard, the use of the proposed installation for drying wood is economically feasible, due to the rational use of electricity, simplicity and reliability of the design and the reduction of capital costs.

Claims (1)

A wood drying installation comprising two vacuum chambers with inside mounted heaters, fans, longitudinal partitions forming an aerodynamic path of movement, a steam generator and a trolley for placing the dried wood inside the chamber, characterized in that the vacuum chambers are supplemented by steam ejectors connected to the steam generator, a suction line which is connected to an adjacent chamber, installed inside the heaters act as condensers spent steam ejectors.