RU2206842C2 - Drying chamber for lumber - Google Patents

Abstract

FIELD: processes for drying lumber, particularly convective periodical-action chambers, possibly drying lumber in wood working, furniture making and other industry branches. SUBSTANCE: drying chamber includes blower forming horizontal circulation circuit for drying agent; system for heating drying agent; system for condensing moisture of drying agent; heat insulation housing. Novelty is at least one lengthwise frame-type partition formed by two vertical prismatic struts mounted on lower horizontal shield and mutually joined through upper horizontal beam. Frame type partition divides stacked lumber by two portions in such a way that edges of both portions of stack engage with vertical struts of frame type partition. Drying agent is fed inside frame type partition. The last is provided with two vertical multiple-link movable plate shields and with upper horizontal shield mounted with possibility of vertical motion by value of stack shrinkage at drying. In variant frame type partition may be arranged on stack carriage. EFFECT: enhanced efficiency of drying process. 4 cl, 6 dwg

Description

 The invention relates to techniques for drying wood, in particular to batch chambers with convective heat transfer, designed for drying lumber in the woodworking, furniture and other industries.

 Known chambers for drying lumber with forced circulation of a drying agent, having heat-insulated walls, a heat source and a fan with a recirculation system of an air drying agent having discharge and suction channels (AS USSR 705218 dated 06/21/1978, class F 26 V 9/06; RF patent 1672172 of 09/28/1989, class F 26 B 9/06; as well as drying chambers "СПЛК-2", "ВАЛМЕТ", "URAL-72", described in the book Sokolov P.V. . and other Forestry chambers. M .: Forest industry, 1987).

 The disadvantages of these designs are aerodynamic losses in the recirculation channels of complex configuration and considerable length, leakage of the injected drying agent past the stack with lumber, the presence of a recirculation channel for supplying a heated drying agent under excess pressure, which has heat exchange with heat-insulating walls (enclosure) of the chamber, which also creates increased heat loss.

 All this reduces the efficiency and effectiveness of the drying process.

 Also known is the installation for drying UT-3 of the company "UTEK" (Sweden) (see Sokolov P.V. et al. Dehumidifying chambers. M: Forest industry, 1987, p. 79, 80) with transverse-horizontal circulation, in which the drying agent is pumped into the space between two rows of stacks. The disadvantage of this design is the significant leakage of the drying agent past the stack, since the flat end vertical screens do not provide an exact fit to the end of the stack due to the difference in the length of the lumber in the stack, the arbitrary shape of the end of the lumber and the inaccuracies in laying lumber in the stack. The installation is the closest in technical essence to the proposed design and is selected as a prototype.

 The aim of the invention is to increase the efficiency of the drying process of lumber by improving the efficiency of blowing the stack and reduce losses.

 This goal is achieved by the fact that the drying chamber for lumber, containing a fan, forming a circulation circuit with discharge and suction channels, bounded by vertical walls of the chamber, a stack with lumber, and also upper and lower horizontal screens, providing horizontal circulation of the drying agent; a drying agent heating system, for example, heaters; a moisture condensation system of a drying agent, for example a refrigeration unit with an evaporator located in the circulation channel; insulated housing; contains at least one longitudinal vertical frame partition formed by two prismatic vertical posts connected by an upper horizontal beam, dividing the stack with lumber into two parts, the edges of the lumber of both parts of the stack contacting the vertical posts of the frame partition, one partition wall has an opening for supplying a drying agent under pressure, and the other is equipped with two flexible vertical screens, made, for example, in the form of mobile multi-link plas tin and placed inside the frame partition; the upper screen is made in the form of several U-shaped horizontal plates covering the upper horizontal beam of the frame partition and installed with the possibility of vertical movement by the amount of vertical shrinkage of the stack during drying; in one embodiment, the frame partition is mounted on the lower horizontal screen (bottom) of the drying chamber, and in another embodiment, the frame partition can be placed on a stacking trolley rolled out of the drying chamber to load lumber; the lateral surfaces of the vertical prismatic racks of the partition wall in contact with the edges of the lumber can be coated with an elastic sealing material, for example rubber, and, in addition, the moisture condensation device of the drying agent may contain at least one plate of heat-conducting material, for example metal, installed with a gap on the inner wall of the insulated fencing of the drying chamber, for example on a door that can be turned outward, and the stove is equipped with a condensate collector otkom installed in its lower part, and a sealant installed on the edge of the plate, emerging when turning the wall of the drying chamber out.

Figure 1 presents the drying chamber, a view in plan;
figure 2 is a section aa in figure 1;
figure 3 is a section bB in figure 2;
figure 4 - multi-drying chamber, view in plan;
5, 6 - design options of a drying chamber equipped with an additional moisture condensation device.

 The drying chamber for lumber contains a thermally insulated fence 1, a centrifugal fan 2 with a vertical axis of rotation, heaters 3 for heating the drying agent, a cooling unit 4 with an evaporator 5, a vertical rack 6 of the partition wall with an opening 7 for supplying the drying agent, a vertical rack 8 of the partition wall, bearing two multi-link plate screens 9, mounted with the possibility of rotation of each link on the vertical axes, a horizontal heat-insulated screen-bottom 10, bearing racks 6 and 8, mountains isontal beam 11 connecting the struts 6 and 8, horizontal upper screens-clamps 12, having cutouts 13 in vertical flanges covering the beam 11. Vertical struts 6 and 8 may have elastic sealing pads 14, for example, of sheet rubber, on their lateral surfaces, fixed on the outer surface of the racks. The side walls 15 and 16 of the drying chamber are hinged on hinges to provide bilateral lateral loading of lumber.

 The drying chamber operates as follows. Having lifted up the walls 15 and 16 and the clamp screens 12, lumber is loaded into the chamber. Pre-set the configuration of the screens 9, ensuring the effective movement of the drying agent in the area of the vertical rack 8 (the most remote from the fan 2 zone). Lumber is laid on the screen-bottom 10 through transverse gaskets so that the edges of the lumber fit snugly against the side walls of the racks 6 and 8, i.e. contacted them on both sides, lower the clamp screens 12 to contact the top of the stack and close the side walls 15 and 16, thereby sealing the chamber.

 During the drying process, the drying agent is supplied under overpressure by the fan 2 through the opening 7 into the frame partition and is evenly distributed over the stack. Outside the stack, fan 2 creates reduced pressure. The drying agent is heated by two groups of heaters 3. In the lower part of the heat ventilation section of the chamber there is a moisture condensation system from the drying agent, consisting of a refrigeration unit 4 with an evaporator 5, separated by a horizontal partition with a window 17 equipped with a valve 18, from the channel through which the fence is taken air by fan 2. When the valve 17 opens the window 17 through the evaporator 5 passes part of the moist warm air that is removed from the stack. Water vapor condenses on the cold surface of the evaporator 5, condensate is collected in a tray and is gravity-discharged out of the pipe.

 The multi-stage nature of the screens 9, in addition to the possibility of creating the wall configuration optimal for purging in the end part of the stack, also allows drying lumber much shorter than the largest determined by the distance between the racks 6 and 8. In this case, part of the screen 9 is installed parallel to the longitudinal axis of the stack. forming, thereby, a sealed vertical wall, which is a continuation of the side surface of the rack 8, and the remaining part of the screen 9 is profiled to optimize the air flow.

 Elastic sealing pads 14 on the lateral surfaces of the vertical racks 6 and 8 serve to more effectively seal the contact areas of the edges of the lumber in the stack with the surface of the racks, while the pressure loss of the drying agent from its leaks along the edge of the lumber and the accuracy of the fit of the edge of the lumber to the rack are reduced, thereby simplifying the process of laying lumber for drying.

 In addition to the design variant of a single-stacked drying chamber with side loading without a stacking cart shown in FIGS. 1-3, various construction options of such a chamber with one or more rolling out stacking carts equipped with frame partitions are possible, for example, as shown in FIG. 4. In this case, the stacking of the stack on the cart is carried out similarly to the outside of the chamber (i.e., close to the frame partition of the cart), and when the cart with the stack is rolled into the chamber using elastic seals, the frame partition window of each cart is hermetically sealed with the corresponding blower nozzle.

 To remove a large amount of moisture from the drying agent at the initial stage of drying, the drying chamber may be equipped with at least one moisture condensation device consisting of a plate 19 (20) mounted on the inner side of the wall - door 15 (16) (Fig. 5) or swing gates - doors (6) with a gap, so that the plate 19 (20) forms a flat gap with the inner surface of the insulated fence. In the lower part, the plate 19 (20) is equipped with a condensate collection tray 21 (22) in communication with a drain pipe (not shown). The edge of the plate 19 (20), coming out when the door is opened outside the drying chamber, is equipped with a seal 23 (24).

 With the door ajar, air entering outside and having a temperature lower than the temperature of the drying agent inside enters the gap between the stove and the inner surface of the door. The intake of external air is ensured by the vacuum created by the fan 2 outside the pile with lumber. Condensation forms on the surface of the plate 19 (20), flowing down into the tray 21 (22) and discharged to the outside by gravity through the drain pipe. The amount of incoming outside air is controlled by the angle of opening the door and, accordingly, the size of the gap. The seal 23 (24) prevents the flow of outside air into the chamber, bypassing the gap.

 Dividing the stack by the frame partition into two parts makes it possible to reduce the width of the stack parts and thereby improve the blowing conditions by reducing the length of the gap formed by the sawn timber laid on the gaskets, the edges of both parts of the stack contact the racks of the frame partition and the upper movable and two flexible multi-tier screens eliminates leakage past a stack of a heated drying agent, injected under pressure into the frame partition (i.e., into the space between the parts of the stack), and allows it efficient and cost effective purging the drying agent through the timber. Finding the end parts of the lumber in the zone of reduced speed of the drying agent also helps to align the drying speed of the lumber along the length, i.e. increases drying efficiency and economy. The presence of only rarefaction zones outside the stack contributes to the preservation of the drying agent inside the chamber, which also increases the drying efficiency. Elastic sealing pads on the side surfaces of the uprights of the frame partition reduce the pressure loss of the drying agent passing through the stack and reduce the power consumption of the fan. An additional moisture condensation device of the drying agent, made in the form of a plate installed on the door of the drying chamber, allows you to accelerate the process of removing moisture from lumber and, thereby, reduce the energy costs of drying.

 Thus, the proposed technical solution ensures the achievement of the purpose of the invention and has advantages over existing analogues and prototype.

Claims (4)

 1. A drying chamber for lumber, comprising a fan forming a circulation circuit with discharge and suction channels bounded by vertical chamber walls, a stack with lumber, and upper and lower horizontal screens providing horizontal circulation of the drying agent; a drying agent heating system, for example, heaters; a condensation system, moisture of the drying agent, for example, a refrigeration unit with an evaporator located in the circulation channel; a heat-insulated casing, characterized in that the chamber contains at least one longitudinal vertical frame partition formed by two prismatic vertical posts connected by an upper horizontal beam, dividing the stack with lumber into two parts, the edges of the lumber of both parts of the stack in contact with the vertical posts of the frame partition, one partition of the partition has a hole for supplying a drying agent under pressure, and the other is equipped with two flexible vertical screens, you filled, for example, in the form of movable multi-link plates and placed inside the frame partition, the upper screen is made in the form of several U-shaped horizontal plates covering the upper horizontal beam of the frame partition and installed with the possibility of vertical movement by the amount of vertical shrinkage of the stack during drying.  2. The drying chamber according to claim 1, characterized in that the frame partition is installed on the lower horizontal screen (bottom) of the drying chamber.  3. The drying chamber according to claim 1, characterized in that the frame partition is mounted on a stacking trolley rolled out of the drying chamber to load lumber.  4. The drying chamber according to claim 1, characterized in that the side surfaces of the vertical prismatic racks of the frame partition in contact with the edges of the lumber are coated with an elastic sealing material, for example rubber.

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