KR20020038169A - Automatic wood drying system - Google Patents

Abstract

PURPOSE: An automatic timber drying system is provided to simply dry the timber by automatically applying a drying schedule suitable to various timbers by databasing the timber drying schedule. CONSTITUTION: A software comprises a drying schedule database(1), an automatic timber drying program(2) and the drying process setup data(3) and a hardware comprises a data obtain and card connector(4), an A/D converter(5), a D/A converter(6), a digital I/O(7), an amplifier and multiple transmission board(8), a wet and drying bulb temperature sensor(9), a humidity sensor(10), an electronic scale(11), a thermocouple temperature sensor(12) and a converter(13), an open/close device of a ventilator(14), a fan(15), a watt-time meter(16), an electronic open/close device of the solid state(17), a heater(18), and a humidifier(19). The drying schedule database is constructed by classifying the timbers into a large class, a middle class, a small class, an English name, a scientific name and a thickness and discriminating into the domestic, the north America, the Asia/Oceania, the Africa, the middle and south America and the others, and dividing into various thickness.

Description

Automatic wood drying system

The present invention relates to a wood drying automation system, and in particular, the present invention relates to an automated system for simply drying wood by automatically applying a drying schedule suitable for wood by making a wood drying schedule into a database.

The conventional Dedrick has developed a new concept of wood drying schedule, called continuously rising temperature schedule, which continuously raises the temperature according to the moisture content of wood during drying by breaking the existing multi-stage temperature rise schedule. Nasif had proposed a continuously varying schedule with a slight modification of the schedule of continuous temperature rise.

The new concept of the drying schedule can only be determined and controlled by air conditions in accordance with the change of conditions during drying, so that the practical application is almost impossible unless the automation of the wood drying system is preceded.

In addition, social phenomena trying to avoid poor working conditions along with the recent rise in wages are a great burden for the wood industry, which has a relatively poor working environment, and the wood drying automation field has been led by the computer industry, which was developed rapidly in the 1980s. Many studies have been carried out, and various types of wood drying automation systems have been developed, mainly from dryer manufacturers.

At present, there are dozens of companies producing automatic control equipment for drying wood, and each product is an electronic temperature / humidity recorder equipped with a wet and dry bulb temperature sensor, which is most used in existing drying systems. The European style, which uses a resistive moisture meter, an electric temperature / hygrometer, and a wind speed sensor, is a more advanced form. In the program system that uses a programmable logic controller (PLC) or a universal digital controller (UDC), the desired drying schedule can be entered and automatically entered. Can be controlled.

In large-scale wood drying plants, distributed control or centralized control, which can control several drying chambers simultaneously from a central computer, was applied to actual sites.

However, there is a problem that it is difficult to find a suitable drying schedule suitable for the target species, thickness and other characteristics because the drying schedule is very diverse enough to have different characteristics depending on the species and thickness and the place of origin.

Another problem is that workers engaged in wood drying do not have sufficient theoretical knowledge about wood drying, so there is a high possibility of improper drying conditions being applied.

Accordingly, an object of the present invention is to provide an automated system for simply drying wood by automatically applying a drying schedule suitable for a variety of wood by the database of the wood drying schedule.

The present invention for achieving the above object can be applied to the appropriate drying schedule to the drying target wood only by simple operation by database the wood drying schedule, and at a glance the situation change for almost all conditions related to air and wood in the drying room during drying It is clear that the shortage of raw material supply already experienced by the Wood Resources Bureau's resource protection policy will be further developed in the future. The drying schedule database of domestic materials was added to the wood drying automation system developed above, and in the case of species that have not been identified so far, it only achieved the function of automatically estimating and applying the drying schedule by measuring its specific gravity.

1 is a block diagram of a software and hardware configuration of a wood drying automation system of a preferred embodiment of the present invention;

Figure 2a is an exemplary view of the software main screen of the wood drying automation system of the preferred embodiment of the present invention,

Figure 2b is an illustration of a drying schedule table database of the wood drying automation system of the preferred embodiment of the present invention,

Figure 2c is an exemplary channel setting of the wood drying automation system of the preferred embodiment of the present invention,

Figure 3 is a program flow diagram of the wood drying automation system of the preferred embodiment of the present invention,

Figure 4 is a flow chart of drying characteristics and drying stress and optimum drying schedule of the wood drying automation system of a preferred embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

1: drying schedule database 2: wood drying automation program

3: drying process setup data 4: data acquisition and card access

5: analog / digital converter 6: digital / analog converter

7: digital input / output 8: amplifier multiple receiving board

9: wet and dry bulb temperature sensor 10: humidity sensor

11: electronic scale 12: thermocouple temperature sensor

13: switch 14: ventilation opening and closing device

15: Fan 16: Watt, Hour, Meter 1

17: solid state electronic switch

18: heater 19: watts, hours, meters 2

20: humidifier

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings for a preferred embodiment.

Figure 1 is a block diagram showing the software and hardware configuration of the wood drying automation system of the preferred embodiment is configured as follows.

The software consists of a drying schedule database, automatic wood drying program, drying process setup data. The hardware includes data acquisition and card connection, A / D converter, D / A converter, digital I / O, amplifier and Multiple transmitter board, wet and dry bulb temperature sensor, humidity sensor, electronic scale, thermocouple temperature sensor and converter, vent opening device, fan, watt / hour / meter, vent opening device, solid state electronic It consists of an opener, a heater, a humidifier, and a watt / hour / meter.

The dry schedule database of the software is divided into large category, middle category, small category, English, scientific name, thickness, and domestic, North American, Asian / Oceania, African, European, Latin American, etc. Enter the drying schedule for about 100 species by dividing the thickness by various standards, and the database is built so that the drying schedule can be created by simply selecting the species and thickness in the drying schedule setting part of the program.

Wood drying automation program of the software is a monitoring window made to see the drying progress at a glance as the main screen of the wood conditioning system as shown in the preferred embodiment shown in Figure 2a A / water content, temperature, humidity, wind speed It reads from the D (analog / digital) channel and displays it in numerical value and bar bar and shows the overall drying progress. The TDAL (Temp Drop Across the Lumber pile) term indicates the air temperature difference between the residual inlet and the outlet. It represents the amount of heat energy transferred from the wood to the wood.

In addition, Figure 2b shows a drying schedule table generated using the drying schedule code of the preferred embodiment to calculate the moisture content using the weight of the wood test piece obtained from the dryer and the pre-measured total dry weight and calculated from the drying schedule table It finds the section of the moisture content and compares it with the air condition for the section and decides the heater / humidifier to ON / OFF and sends it to an electronic relay to control it.

In addition, FIG. 2C illustrates a channel setting portion of a preferred embodiment, in which the channel setting portion is configured to set up an environment for proper communication between a program and hardware, and the control program has an analog-to-digital (A / D) conversion function. It communicates with the converter to input data, inputs which sensors are connected to each of the 16 A / D (analog / digital) channels, sets the gain value, and operates the test buttons as the hardware connection. Pressing to check the output value, it shows three thermocouples J type, electronic scale for measuring wood moisture content during drying, wet and dry bulb temperature, relative humidity, IR sensor (information retrieval sensor), respectively.

The drying schedule and the estimation of the unknown tree drying schedule are described as follows.

The drying schedule is selected from the pre-entered database and the corresponding thickness is selected. If the thickness is selected, the drying schedule code is created. If the dry schedule code is pressed with the schedule creation button, the drying schedule is automatically created. There are interval, dry bulb temperature and wet bulb temperature difference, and wet bulb temperature items, which are compared with the data input from the dryer.

Next, the unknown species drying schedule of the present invention is to measure the specific gravity of the wood to be dried in case the drying schedule of the species to be dried is unknown or it is difficult to obtain information about it, it is possible to present an appropriate schedule The relation of is as follows.

T _i = 1 / (0.00115 + 0.0167 Gb)

D _i = 1 / (0.0832 + 0.509 Gb)

G _b : Specific gravity (Oven dry weight (g) / Volume of green wood (cm 3))

T _i : Initial dry bulb temperature (℃)

G _i : Wet bulb temperature difference (℃)

The dry bulb temperature is increased by 5.6 ° C for every 5% of water content decrease from 30% of water content, and the terminal temperature is applied at 15% or less of water content. In this case, if the specific gravity is less than 0.75, 82 ℃ is applied as the terminal temperature, and if the specific gravity is more than 0.75, 71 ℃ is applied. On the other hand, the wet and dry bulb temperature difference is gradually increased from the water content 45% and the wet and dry bulb temperature difference for each moisture content step is determined by the following equation.

However, the maximum allowable wet bulb temperature difference was 27.8 占 폚, and the minimum allowable wet bulb temperature was 32 占 폚.

D = a exp (-bM)

D = wet and dry bulb temperature difference (℃)

M = moisture content (%)

a = 1 / (0.0011 + 0.00124 Di)

b = 1 / 0.14-0.0458 ln (Di)

The drying process setup data of the software shows an environment setting for proper communication between the program and the hardware in the channel setting portion of FIG. 6. The control program communicates with an analog-to-digital converter capable of A / D conversion to obtain data. Input the sensor and input the sensor for each of the 16 A / D channels, set the gain value, and check the output value by pressing the test button to check the output value. An electronic scale for measuring wood moisture content during drying, a dry / wet bulb temperature, relative humidity, and an information retrieval sensor were connected.

The data acquisition and card connection unit of the hardware receives data from the wood drying automation program and connects the A / D converter, the D / A converter, and the digital input / output card.

The A / D converter of the hardware converts an analog signal into a digital signal, and is composed of an amplifier, a multiple reception board, a wet and dry bulb temperature sensor, a humidity sensor, an electronic scale, and a thermocouple temperature sensor.

Among the A / D converters of the hardware, amplifiers and multiple reception boards are used to amplify electrical signals output from various sensors.

The dry / wet bulb temperature sensor of the A / D converter of the hard air is designed to use a thermocouple (J type) for measuring the temperature inside the wood or other temperature such as TDAL (Temperature Drop Across the Load). The temperature measurement of the wood surface during drying is done using an infrared temperature sensor.

Humidity sensor in the A / D converter of the hardware is a humidity measurement by the wet and dry bulb thermometer method is not only a slow response speed, but if the proper air flow is not made in the wet bulb portion, the reliability of the measured value is low, so use the electronic humidity sensor for high temperature. I used it.

The electronic balance of the A / D converter of the hardware is a compression type electronic scale for automatically measuring the moisture content of wood during drying.

The thermocouple temperature sensor of the A / D converter of the hardware is designed to stabilize the output even at a temperature of 80 ° C. or higher, and input correction data of the output signal at each temperature control to reduce a slight error.

The D / A converter of the hardware converts a digital signal into an analog signal and is composed of a converter, a fan, a watt / new / meter, and a vent opening device.

The converter of the D / A converter of the hardware adjusts the rotation speed of the motor by a frequency modulation method.

The fan of the D / A converter of the hardware is controlled by the rotation speed is mounted on the motor to give a proper wind speed.

Watt / hour / meter in the D / A converter of the hardware measures the energy required to operate the fan.

Ventilation opening and closing device of the D / A converter of the hardware is to place the windshield in the ventilation opening to adjust the degree of opening and closing through a damp motor (damp motor).

The digital I / O of the hardware is a digital input / output unit that processes inputs and outputs for a drying process, and is composed of a solid state electronic opener, a heater, a humidifier, and a watt / hour / meter.

The electronic electronic opener in the solid state of the digital I / O of the hardware has a large impact on the dry energy due to the discharge of wet air and the inflow of dry air, so excessive exhaust or intake causes waste of energy. The degree of opening and closing was controlled by a damp motor.

The heater in the digital I / O of the hardware controls the amount of heat in drying wood.

The humidifier in the digital I / O of the hardware is to adjust the amount of humidity by applying an appropriate relative humidity to the moisture content level according to the drying schedule.

Watt / hour / meter of the digital I / O of the hardware is to measure the energy required during drying.

Figure 3a is a flow chart of the wood drying automation program of the preferred embodiment consists of the following steps.

Inputting species, thickness, target function rate;

A database search step;

A drying schedule creation program step;

Specific gravity input or correction step;

A drying schedule program estimating step;

Estimated scan review;

A dryer operating step;

A moisture content measuring step;

Applying temperature, humidity, and wind speed for each moisture content step;

Moisture content ≤ target moisture content step;

It consists of a drying termination step.

The species, thickness, and target function rate input step are classified into major classification, middle classification, small classification, English, scientific names, domestic, North American, Asian / Oceania, African, European, Latin American, etc., and various standard thicknesses. Enter the tree and the desired target function rate for the tree.

The database search step is to determine whether it is possible to dry with the inputted contents when the species, thickness, and target function ratio are input.

The drying schedule creation program step is to code the data of the wood entered in the database search step to perform the drying schedule creation program according to the species and thickness.

The specific gravity input or correction step is to dry wood using specific gravity when it cannot dry with the data input in the database search step.

The drying schedule program estimating step is to modify an estimation program for drying unknown species using specific gravity.

The estimation of the estimated schedule starts with inputting the weight again if the weight of the tree is incorrectly entered, and proceeds to the operation of the dryer if it is in the estimated schedule.

The dryer operation step is to operate the dryer appropriately for the tree with the data of inputting the species, the thickness and the specific gravity.

The moisture content measurement step is to measure the moisture content during drying, the formula is as follows.

Dry matter-based moisture content calculation method = (current weight-full weight / total weight) × 100%

The application of temperature, humidity, and wind speed for each moisture content step calculates the moisture content in the moisture content measurement step, finds the interval of the moisture content calculated from the drying schedule table, and compares the temperature, humidity, wind speed, and air conditions with the heater, Moisture, etc. to determine the on / off and send it to the electronic switch to control.

If the moisture content ≤ target moisture content step is the same as or greater than the measured moisture content, the process proceeds again in the water content measurement step, otherwise proceeds to the drying end step.

The drying end step is to stop the operation of the drying system or to activate the alarm function.

4 is a flowchart showing the drying characteristics and the drying stress and the optimum drying schedule of the preferred embodiment, the excess drying rate should be the maximum drying stress is greater than the allowable stress, which leads to deterioration of the drying and quality and under-drying rate is the maximum drying stress It must be smaller than this allowable stress, which leads to delayed drying and economic deterioration.

As described above, the labor cost is reduced due to the large amount of time and manpower required in the wood drying process, and the optimal drying schedule is automatically obtained by inputting only the thickness of the wood, the number of species, or only the specific gravity of wood. Because it has the effect of applying it is very useful invention in the wood drying industry.

Claims (5)

The wood drying automation system consists of software and hardware to build a database of thickness and species to automatically search for the optimal drying schedule. It is possible to estimate the drying schedule by weight only for species not identified by species and thickness. Wood drying automation systems. The method of claim 1, wherein the software of the wood drying system is divided into categories, subclassification, English, scientific name, thickness, the drying schedule database and the moisture content, Knowing the overall progress of the temperature, humidity, and wind speed through the A / D channel, TDAL is a wood conditioner automation program that expresses the amount of heat energy transferred from the air to wood, a drying schedule table created using the drying schedule code, Wood drying automation system, characterized in that consisting of the channel setting unit and the drying process set-up data to set the environment for the correct communication between hardware. The hardware of claim 2, wherein the hardware of the wooden drying system receives data and connects the data to an A / D converter, a D / A converter, and a digital input / output card, an amplifier, a multiple receiving board, a wet and dry bulb temperature. The A / D converter consisting of a sensor, a humidity sensor, an electronic scale, a thermocouple, a temperature sensor, a converter, a fan, a watt / hour / meter, a vent opening device, an electronic dog A wood drying automation system comprising a waste machine, a heater, a humidifier, a watt / hour / meter, and an air vent opening device. The method of claim 1, wherein the wood drying automation program Inputting species, thickness, target function rate; A database search step; A drying schedule creation program step; Specific gravity input or correction step; A drying schedule program estimating step; Estimated scan review; A dryer operating step; A moisture content measuring step; Applying temperature, humidity, and wind speed for each moisture content step; Moisture content ≤ target moisture content step; Wood drying automation system, characterized in that consisting of a drying end step. 5. The wood drying automation system according to claim 4, wherein the moisture content measuring step is a dry weight reference moisture content calculation method of the moisture content measuring program function (current weight-total dry weight / total dry weight) x 100%.