RU2338136C1 - Efficient drying chamber - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: invention is related to drying chambers with material heating in air flow and may be used in many industries - for drying and other heat-moisture treatment of different materials. Chamber contains heated casing with closed end apertures for loading and unloading of material and longitudinal vertical diaphragm, and also ventilation device (fan motor assembly) with inbuilt air moisturiser, at that internal space of chamber is isolated from external one, fan motor assembly is equipped with deflector combined with cooling chamber of refrigerating unit, hot heat exchanger of which is installed in outlet channel of fan motor assembly, and deflector is made with annular slot that serves both as condensate tank and ejector, at that casing of fan motor assembly has hatches with gates for reversion of air flow through stack of loaded material. Fan motor assembly is equipped with device for removal of moisture in the form of cooled condensate with the possibility of its usage for repeated moistening of material and other needs, and also system for balancing of heat and moisture treatment conditions in the whole volume of material loaded in the chamber.

EFFECT: reduction of power inputs and provision of high quality of treated produce.

1 dwg

Description

The invention relates to technological equipment for heat-moisture treatment and drying of materials (mainly timber) and can be used in many industries.

There are a number of methods and devices for the heat and moisture treatment of various materials. The most advanced of them - with high-frequency induction heating - provide quick and uniform drying of materials, however, high-frequency installations are expensive in both manufacturing and operation.

Vacuum drying chambers have quite acceptable energy characteristics, but their main drawback is the limited volume, complexity and, consequently, the high cost of the chambers themselves and their maintenance.

Aerodynamic drying chambers are an alternative to the complex equipment considered: they are simple in installation and operation, can work without additional heat sources, provide regulation of the technological mode, and allow a large unit capacity. However, their main drawback is increased energy consumption. So, for example, the ELSA aerodynamic chambers (VNIIDMASH) spend on average about 300 kWh per cubic meter of dried lumber.

High energy costs in chambers operating without evacuation are explained by large heat losses due to the inevitable in the operating mode emission of the coolant - hot humid air - into the surrounding space. At the same time, the heat expended on the evaporation of moisture is also lost.

A known camera with the removal of moisture from the coolant inside the chamber itself by condensation on the cooled panels (Patent RU 2129244, 6 F26В 5/04, 3/34). However, this separation method is used in a vacuum chamber, in this case, the costs associated with the use of running water to cool the panels themselves or the installation of a recycled water supply system are added to the costs of its acquisition and operation. And in any case, a significant part of the heat leaves the cooling chamber from the chamber.

The closest analogue of the claimed device (prototype) is an aerodynamic drying chamber containing a thermally insulated sealed casing, supply and output valves with adjustable dampers, screens dividing the interior of the chamber, a radial fan equipped with a regulator for changing the flow rate and air temperature, as well as heating elements (heating elements, steam registers, smoke tubes) and an adjustable humidifier built into the heat exchanger (Patent RU 2212011, F26В 9/06).

This chamber has certain advantages over similar aerodynamic drying chambers that are in operation by reducing the fan power and improving the adjustable technological mode.

However, the main drawback of such analogues - large heat loss with the removable part of the hot humid air - is fully preserved in the chamber under consideration. In addition, due to the constant directivity of the recirculating air flow, the drying conditions along it are not the same: in the incident flow, where the air humidity is lower, the material dries faster. This adversely affects the quality of drying in general and can cause rejects (for example, cracking or warping of lumber). A similar unevenness will occur when the material is wetted.

The invention is intended to eliminate the above disadvantages of existing drying chambers, to minimize the costs associated with drying materials, both capital and operational.

This goal is achieved by the fact that in the proposed design of an economical drying chamber containing a heat-insulated casing with lockable end openings for loading - unloading material and a longitudinal vertical diaphragm, as well as a fan unit (hereinafter referred to as “fan unit”) with an air humidifier, in accordance with the invention the interior of the chamber is isolated from the outside in order to prevent air exchange between them in the operating mode, the ventilation unit is equipped with a deflector combined with a cooling chamber installation, the hot heat exchanger of which is located in the exhaust duct of the unit, and the deflector is made with an annular gap, which is both a condensate collector and an ejector, while the body of the unit has hatches with gates to reverse air flow through the stack of loaded material.

Isolation of the interior of the chamber from the external environment eliminates air exchange with it, i.e. the entire coolant in the chamber, in a state of recirculation, is maintained throughout the entire technological cycle, and thus, the heat loss in the chamber is reduced only to heat loss through its insulated body.

The combination of the deflector at the outlet of the air stream from the fan unit with the cooling chamber of the refrigeration unit allows you to partially condense and remove moisture from the air stream in the form of chilled condensate, returning to this stream the heat spent on heating and evaporation of moisture. The slit-like ring condensate collector, connected by a tube to an external tank through an adjustable valve and a pump cavity, is an ejector in the humidification mode.

Placing a hot heat exchanger in a swirling air stream at the outlet of the fan unit creates the best conditions for heat transfer and utilization of thermal energy of the refrigerant.

Equipping the inlet and outlet hatches of the ventilation unit body with a switchable gate block allows you to periodically change the direction of the air flow in the channels between fragments of the stack, which is necessary to even out the drying or wetting conditions of the material without reversing this flow inside the ventilation unit itself.

The essence of the claimed invention is described below in the description of the device and the camera and is illustrated in the drawing, which shows a General view of the camera in its cross section.

An economic drying chamber (ESC) contains a heat-insulated housing 1 (see the drawing) with one or two end openings closed (for non-passage or passage execution, respectively) and a longitudinal vertical diaphragm 2 adjacent to the roof and ends of the chamber, as well as to the walls of the housing 3 ventilation unit (s), inserted (inserted) into the diaphragm gaps, and having inlet (intake) and outlet hatches 4 with gates 5. The ventilation unit is equipped with an impeller 6 with an engine 7, a funnel-shaped deflector 8, structurally combined with bolochkoy cooling chamber with an annular sprayer 9, which via a throttle 10 is connected to the outlet channel disposed in the fan unit 11, a heat exchanger connected to the compressor 12 of the refrigeration unit. Opposite the exit hatches 4, if necessary, there may be additional air heaters of known design. The deflector 8 at the level of the bottom of the cooling chamber has an annular gap with a condensate chamber 13 connected through an adjustable valve 14 and a centrifugal pump 15 to the reservoir 16. The vertical diaphragm 2, ending at the top of the loading openings of the chamber, is a movable curtain 17 of known design.

The inventive ESC works as follows: the material to be dried, for example a parquet blank, is loaded with a blown stack in the housing 1. The diaphragm 2, as well as the movable curtain 17 and its mechanical seals lowered onto the stack, provide separation of the chamber’s internal space into two zones, communicating only through the working cavity of the ventilation unit with a drive motor 7 and inlet and outlet hatches 4 in its housing 3 and through the gaps between the fragments of the loaded material. When the fan unit is turned on, the drying agent - air - passes through simultaneously open entrance hatches 4 - from one zone - and exit - into another zone - and then through a blown stack, undergoing aerodynamic heating. In the drying mode, the air collects the evaporated moisture and swirls into the cooled surface of the deflector 8, where it is discharged in the form of condensate through the annular gap into the chamber 13 and then through a pipeline with an adjustable valve 14 and a pump 15 to the reservoir 16. The air flow itself, which was discharged by such Thus, part of the moisture at the outlet of the ventilation unit receives additional heat from the hot heat exchanger 11 of the refrigeration unit and, if necessary, from other heat sources, which in this case can be installed opposite the output Cove 4. In this condensed refrigerant in the heat exchanger 11 is directed through the choke 10 into the sprayer 9 of the cooling chamber, where - in the evaporated (at its walls) state - re-enters the compressor 12 of the refrigeration unit.

In the humidification mode of the material, when the refrigeration unit is turned off, the pump 15 delivers the liquid through the valve 14 into the chamber 13, from where it enters the air stream through the annular gap and is sprayed therein. Humidified air passing through the stack increases the moisture of the material.

All technological parameters are provided with the ability to control within the necessary limits by changing the throughput of the valve 14, the speed of the engine 7, as well as the use of additional air heaters. Reversal of the air flow through the stack (to even out the drying and moistening conditions of the material) is carried out by the coordinated switching of gates 5. All processes of heat-moisture processing of the material can be automated.

Thus, the use of the inventive ESC will dramatically reduce the loss of thermal energy in such a large-scale and energy-intensive technological process as heat and moisture treatment of materials, ensuring high quality of the latter.

Claims (1)

An economical drying chamber containing a heat-insulated casing with lockable end openings for loading - unloading material and a longitudinal vertical diaphragm, as well as a fan unit (ventilation unit) with an integrated air humidifier, characterized in that the inner space of the chamber is isolated from the outside to prevent air exchange between them in operating mode, the fan unit is equipped with a deflector combined with the cooling chamber of the refrigeration unit, the hot heat exchanger of which is located in the exhaust duct regatta, and the deflector is made with an annular gap, which is both a condensate collector and an ejector, while the ventilation unit body has hatches with gates to reverse the air flow through the stack of loaded material.