JPS5849887A - Method and device for controlling blast in veneer drier - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Objective of the Invention) The present invention provides a method for blowing hot air across or parallel to the conveying direction of a plywood veneer in a furnace housing a conveying member such as a net, a roll or a chain, or a chain with a fork. In a veneer dryer equipped with a fan that circulates air, a heater, or other hot air generation source, a frequency conversion type air blow control method for controlling the air flow rate of the fan in inverse proportion to the temperature of the hot air, and an apparatus for implementing the method. The purpose of this is to dry veneer sheets with high moisture content because the induction motor that drives the air circulation fan installed in this type of veneer dryer is rotated at a constant commercial frequency from beginning to end. Even during periods when the hot air temperature inside the furnace drops, which requires additional drying energy when boards are brought into the furnace, low-moisture-content wood veneers are brought into the furnace. In order to solve the problem of lack of responsiveness, in which the amount of air blown by the blower inside the furnace does not change at all even during periods when the hot air temperature inside the furnace increases and the drying energy becomes redundant, the temperature of the hot air decreases. At times when extra drying energy is required, the amount of air blown by the fan inside the furnace is increased to increase the drying energy. This is an improvement that reduces the amount of air blown by the fan inside the furnace to save drying energy.

(Structure of the Invention) - The present invention provides a method for transporting the veneer veneer 3 crosswise or parallel to the transport direction in the furnace body 2 which houses transport members such as nets 1a, 11), row A/1c or a chain, or a chain with a fork. In a veneer dryer that is equipped with a fan 4 that blows and circulates hot air, a heater 5, and other hot air generation sources, the frequency of the power supply that is supplied to the induction motor 6 that drives the fan 4 is controlled by the furnace that blows and circulates hot air. A method for controlling air blowing in a veneer dryer in which the temperature is controlled in inverse proportion to the temperature of hot air inside the furnace body 2, a fan 4 that blows and circulates hot air inside the furnace body 2, and an induction motor 6 that drives the fan 4t. , a frequency converter 7 capable of converting the commercial frequency of the power supply supplied to the induction motor 6, a temperature sensor 8 for measuring the temperature of the hot air inside the furnace body 2 that is blown and circulated by the fan 4, and the temperature sensor. This is an air blow control device for a veneer dryer, which comprises a proportional controller 9 that adjusts the set value of the frequency converter 7 in inverse proportion to the measured value of the frequency converter 8.

That is, in the case of a continuous type veneer dryer, which is an example of the present invention, as shown in FIG.
The conveying members consisting of 1) are housed in multiple stages in a furnace body 2, and a large number of fans 4 and heaters 5 are provided for blowing and circulating hot air across the conveyance direction of the veneer veneer 3 within the furnace body 2. In the case of a veneer dryer or a roll-type veneer dryer, as shown in Fig. 2, a conveying member consisting of rolls 1C is stored in multiple stages in a furnace body 2, and a veneer veneer 3 is dried in the furnace body 2. In a veneer dryer equipped with one or more fans 4 and a heater 5 that blow and circulate hot air in parallel to the conveying direction, the commercial frequency (usually 50 to 50 6
0 to μ) in inverse proportion to the temperature of the hot air inside the furnace body 2 that the fan 4 blows and circulates, that is, as the hot air temperature inside the furnace body 2 gradually decreases from a predetermined hot air temperature, the fan 4 Convert the frequency so that the commercial frequency of 50 to 60 points of the power supply A supplied to the induction motor 6 that drives the is gradually converted to a higher frequency,
This air blowing control method is inversely proportional to the hot air temperature, in which the rotation speed of the induction motor 6 and the fan 40, which rotate substantially in synchronization with the frequency, is increased continuously from a predetermined hot air temperature to a lowered hot air temperature. The change in the operating capacity of the induction motor 6 during operation will depend on the installed capacity, but for example, the furnace body 2 may
Fan 4 with an installed capacity of 3QKllV circulates air inside the
And the change in the operating capacity of the induction motor 6 changes the predetermined hot air temperature in the furnace body 2, that is, the hot air temperature at the highest value and the hot air temperature Fjt at the lowest value, for example, from 200°C to 18°C.
When assuming that the temperature is 0°C, the rotation speed of the commercial frequency at the lowest value is raised from the airtight Hertz equivalent at room temperature to about 70 μT, and the induction motor 6 is operated at its maximum. Approximately 3QK, which roughly matches the capacity to the installed capacity.
W, and at the highest value, the rotation speed is inversely proportional to the temperature rise in the furnace body 2, and in this case, the rotation speed is changed from the equivalent of 70 Hz at the lowest value to 60 Hz, which is the normal commercial frequency.
It is controlled in inverse proportion to reduce the temperature to a level equivalent to Hertz or lower.

The commercial frequency for the power supply supplied to the induction motor 6 that drives the fan 4 described above for paddy rice is adjusted to the temperature of the hot air inside the furnace body 2 that is blown and circulated by the fan 4, and the frequency is converted in inverse proportion. The adjusting means for controlling is composed of an electronic element etc. that converts the commercial frequency of the power supply A supplied to the induction motor 6 into an arbitrary frequency, as shown in FIGS. 1 and 2 as examples of the control system. A frequency converter 7 is inserted between the power source A and the induction motor 6, and a temperature sensor 8 such as a thermocouple or thermistor is preferably used to detect temperature variations in the hot air inside the furnace body 2, which is blown and circulated by the fan 4. A proportional controller 9 is installed in each air circulation path of the fan 4 and is configured to be able to adjust the set value of the frequency converter 7 inversely proportionally according to the hot air temperature measured by the temperature sensor 8. is inserted between the temperature sensor 8 and the frequency converter 70 to constitute a series of frequency conversion control system. In this case, the proportional controller 9 is configured so that when the temperature sensor 8 measures the hot air temperature of 180°C, which is the lowest value in the furnace body 2, the set value of the frequency converter 7 is approximately 70 Hz. To,
Also, when the temperature sensor 8 measures the hot air temperature at the highest value in the furnace body 2, that is, at ro o degrees Celsius, the set value of the frequency converter 7 is 60 Hz, which is the normal commercial frequency, or lower. The structure is such that the frequency is converted approximately in inverse proportion between the two. Of course, the above-mentioned example is just an example of implementation, and by appropriately changing the reduction ratio between the fan 4 and the induction motor 6, the frequency conversion from the power source A by the frequency converter 7 can be changed. Numerical values and their ranges can be freely changed.

(Effects of the Invention) As described above, the present invention controls the frequency of the power supply supplied to the induction motor 6 that drives the fan 4 in inverse proportion to the temperature of hot air inside the furnace body 2 that is blown and circulated by the fan 4. A conversion type air blowing control method, a fan 4 that blows and circulates hot air in the furnace body 2, an induction motor 6 that drives the fan 4, and a power supply A that is supplied to the induction motor 6 to carry out the air blowing control method. a frequency converter 7 capable of converting the commercial frequency of the fan 4;
The air blower is composed of a temperature sensor 8 that measures the temperature of the hot air inside the furnace body 2 through which air is circulated, and a proportional controller 9 that adjusts the set value of the frequency converter 7 in inverse proportion to the measured value of the temperature sensor 8. Since the conventional veneer dryer is configured by a control device, the veneer dryer of the conventional method requires additional drying energy when veneer veneers with high moisture content are brought into the furnace body 2. Even when the temperature of the hot air in the furnace 2 decreases, or when veneer with a low moisture content is brought into the furnace 2 and the drying energy becomes redundant, the temperature of the hot air inside the furnace 2 increases. The inconvenience of lack of responsiveness in which the amount of air blown by the fan in the furnace body 2 does not change at all has been resolved, and the furnace can be turned off during periods when the temperature of the hot air drops and additional drying energy is required. The amount of air blown by the fan 4 inside the furnace body 2 is increased to increase the drying energy, and the amount of air blown by the fan 4 inside the furnace body 2 is decreased when the temperature of the hot air rises and the drying energy becomes redundant. Therefore, according to the present invention, the installed capacity of the fan 4 and the induction motor 6 and their maximum operating capacity can be approximately equal to each other, and thereby Since the effective amount of air blown during operation of the hot air circulating inside the furnace body 2 has been significantly increased, the drying sequence of the veneer veneer 3, which has a strong correlation with the amount of air blown, can be thereby improved. It was possible to simultaneously increase the drying energy by significantly increasing the drying energy, and save drying energy by reducing the amount of air flow during unnecessary periods and eliminating the unnecessary power consumption of the fan 4 and the heat consumption of the heater 5. This is an extremely remarkable invention.

[Brief explanation of drawings]

The figures show an example of the implementation of the present invention, in which FIG. 1 is a side view of a continuous type veneer dryer, and FIG. 2 is a side view of a low μ type veneer dryer. 1a, 1b...-net, 1C...low μ, 2...
Furnace body, 5...Plywood veneer, 4...Guar 7.5...
Heater, 6...Induction motor, 7...
Frequency converter, 8... Temperature sensor, 9... Proportional controller, A... Power supply. Patent applicant Hashimoto Electric Industry Co., Ltd.

Claims (1)

[Claims] (1) A fan, heater, or other hot air generating source that blows and circulates hot air crosswise or parallel to the conveying direction of the veneer veneer in the furnace housing the conveying members such as nets, rolls, chains, and chains with forks. A veneer dryer comprising a veneer dryer, characterized in that the frequency of power supplied to an induction motor that drives a fan is controlled in inverse proportion to the temperature of hot air inside a furnace body that is blown and circulated by the fan. Air blow control method in a dryer. (4) a fan that blows and circulates hot air inside the furnace; an induction motor that drives the fan; (4) a frequency converter capable of converting the commercial frequency of the power supply supplied to the furnace; A veneer dryer comprising: a temperature sensor that measures the temperature of hot air inside the furnace body that is circulated; and a proportional controller that adjusts the set value of the frequency converter in inverse proportion to the measured value of the temperature sensor. Air blow control device.