JPH0674948B2 - Dryer - Google Patents

Description

The present invention relates generally to dryers, and more particularly to dryers for drying grains and the like.

This type of drying device generally includes a control box having a built-in electronic circuit control unit such as a microcomputer, two types of temperature sensors, that is, a sensor for detecting the outside air temperature and a sensor for detecting the hot air temperature. Combustion control is performed according to the procedure described in. That is, the CPU of the microcomputer that constitutes the electronic circuit control means
Is the drying target temperature (T _C ) corrected by the outside air temperature (T _A ) and the inside of the drying device that is received from the hot air temperature detection sensor, taking in the outside air temperature sensor information (T _A ) given from the outside air temperature detection sensor. A comparison is made with the temperature (T _B ). The CPU outputs an on-time variable fuel supply amount control pulse signal to the valve drive circuit to control the fuel supply system based on the comparison. The reason for controlling the fuel flow rate by varying the on-time duration of the control pulse signal is that it is difficult to actually measure and directly control the fuel flow rate flowing into the burner combustion system. Along with this, the CPU also drives a fan drive circuit with a signal obtained by integrating the control pulse signal at a constant rate in order to control the ventilation system that supplies the outside air ventilation to the drying device so that combustion can be performed at an appropriate air-fuel ratio. Output as a command signal.

The CPU controls the fuel of the dryer by the above procedure.

By the way, the amount of fuel flowing through the fuel pump, fuel supply electromagnetic valve, etc. that composes the fuel supply system of the dryer is different for each product even if the on-time width of the fuel supply control pulse signal given from the CPU is the same. The characteristics are not necessarily constant due to variations. Particularly, at the time of initial combustion, when the outside air temperature is extremely low, the oil temperature of the fuel is affected by the decrease, and as a result, the viscous resistance increases and the amount of fuel flowing into the burner combustion system decreases. However, even if the amount of fuel flowing into the burner combustion system is increased to increase the on-time duration of the valve, etc., the viscous resistance is large as described above, so the amount of combustion air supplied from the fan exceeds the fuel flow rate. Will increase. On the contrary, when the outside air temperature is high, the viscous resistance of the fuel becomes small, and the supply amount of combustion air does not increase so much as the fuel flow rate increases. Combustion control over time is difficult.

Therefore, various proposals have hitherto been attempted in order to improve the above problems. For example, when the outside air temperature is high in consideration of the temperature characteristics of the fuel as described above, the fan rotation speed is controlled so that the combustion air amount is increased by a preset ventilation amount. On the other hand, when the outside air temperature is low, the fan rotation speed is controlled to reduce the fuel air amount by a preset ventilation amount, contrary to the above.

However, even in the above proposal, when the outside air temperature is extremely low, it is not possible to correct the amount of combustion air commensurate with the increase in the viscous resistance of the fuel, and therefore there is a problem that stable initial combustion cannot be performed with an appropriate air-fuel ratio. there were.

Therefore, the present invention solves the above problems of the prior art, and an object thereof is to provide a drying device capable of performing stable initial combustion at an appropriate air-fuel ratio in a low temperature range of the outside air temperature.

A feature of the present invention for achieving the above-mentioned object is that the means for supplying a part of the outside air ventilation flowing through the ventilation tube as combustion air and the fuel supply system to the outside air ventilation based on the outside air temperature detected by the outside air temperature detecting means. In a drying device that performs combustion control by controlling the amount and the fuel flow rate to maintain a predetermined relationship, respectively, when the outside air temperature detected by the outside air temperature detecting means is within a predetermined temperature range set in advance. When the amount of combustion air supplied from the combustion air supply means is corrected with a preset basic correction factor, and it is determined that the detected outside air temperature belongs to a low temperature range outside the predetermined temperature range, The drying apparatus is provided with a combustion air amount correcting means for correcting the basic correction rate with a correction rate obtained by recorrecting the basic correction rate through a predetermined parameter.

Embodiments of the present invention will be described below with reference to the drawings.

1 is an overall perspective view of a drying apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view of a burner combustion system used in the drying apparatus according to an embodiment of the present invention, and FIG. 3 is an illustration of the present invention. FIG. 4 is a block diagram according to the embodiment, FIG. 4, FIG. 5, and FIG. 6 are diagrams showing a comparison between the effect according to the embodiment of the present invention and the effect according to the conventional example, and FIG. 7 is a flowchart of the configuration of FIG. Indicates.
1 to 3, reference numerals having the same reference numerals indicate the same.

In FIG. 1, the drying device 1 includes an operation box 3 having a control unit (not shown) and a burner combustion system 5.
And have. The operation box 3 includes a fuel setting device 7 for setting the fuel supply amount to the burner combustion system 5 in a plurality of stages, an adjustment completion switch 9, and a fan adjustment for adjusting the rotation speed of a fan for supplying outside air ventilation into the drying device 1. It is provided with a device 11, an adjusting lamp 13, and operation switches 15 such as a drying switch, a swelling amount switch, a grain type switch, and a set moisture switch.

The burner combustion system 5 includes a fuel tank 17 attached to the wall of the drying device 1, a fuel pipe 25 communicating with the fuel chamber 23 via the fuel tank 17, an electromagnetic pump 19 and an electromagnetic valve 21, and a fan (not shown). ) And the like, and a ventilation tube 27 having the combustion chamber 23 therein. Either one of the electromagnetic pump 19 and the electromagnetic valve 21 is controlled by the fuel supply amount control pulse signal output from the control unit (not shown) (opening / closing driving to control the amount of fuel flowing from the fuel tank 17). In one embodiment according to the invention, the electromagnetic valve 21 is so-called on-time controlled as will be described later.

FIG. 2 shows the main part of the burner combustion system 5 as described above. In the combustion chamber 23, an ignition heater 35 made of a material such as ceramic and the ignition state of the flame in the combustion chamber are detected. Frame rods 33 are provided respectively as shown in the figure. A vaporization cylinder motor 37 whose output shaft is connected to the oil diffuser 32 is attached to the blower chamber 24. The ventilation duct 20 communicates with the ventilation chamber 24.
As shown in the figure, a fan motor 29 and a fan 31 such as a sirocco fan which rotates by the drive of the motor and sends in combustion air are provided.

FIG. 3 is a block diagram of the control unit built in the operation box 3 described above. The microcomputer 10 includes a CPU 101, a memory 103, and an input port 1.
05, input port 107, output port 108, output port 109.

The CPU 101 performs arithmetic logic operation and comparison operation. CPU101
Input information of the digital input circuit 59, input port 105
And the A / D conversion circuit 61 and the input port 107. The information given to the CPU 101 via the digital input circuit 59 includes the drying target temperature setting information, that is, the hot air temperature setting information 6
3. There are safety sensor information 65 and operation information 67. The hot air temperature setting information 63 is a grain circulation system (not shown) in the drying device 1.
The target hot air temperature (T _C ) is automatically set by setting the scale according to the type and the amount of dried grains circulating through the target hot air temperature setting knob 69. The safety sensor information 65 is, for example, an elevator motor, an upper spiral,
A drive system safety sensor group 71 for detecting the drive status of the drying device drive system such as the rotary valve and the lower spiral, and a combustion system safety sensor for detecting the drive status of the drying device combustion system such as the ignition heater and the fuel supply pump (that is, an electromagnetic pump). It is output from the group 73 and. The operation information 67 is given from the operation switch 15 for starting / stopping the dryer motor, igniting, and the like. Other information given to the CPU 101 via the digital input circuit 59 includes the frame rod 33 as shown in the figure.
There is flame detection information 77 given from the flame detection circuit 75 via the flame detection circuit 75.

Information given to the CPU 101 via the A / D conversion circuit 11 includes:
Actual temperature sensor in the dryer, namely hot air temperature sensor
There are actual hot air temperature (T _B ) information 81 inside the drying device 1 output from 79, and outside air temperature (T _A ) information 85 output from the outside air temperature detection sensor 83.

The drive command signal of the dryer combustion system given from the CPU 101 is supplied to the fuel supply pump 19, the fuel supply electromagnetic valve 21, the vaporization cylinder motor through the output port 109 and the digital output circuit 111.
A drive circuit (not shown) of 37 and an ignition heater 35 are provided respectively. The drive command signal of the dryer drive system given from the CPU 101 is sent to the fan motor 2 via the analog output circuit 113.
9 are provided to a driving circuit (not shown).

The memory 103 contains a control program and the like and stores necessary data.

The CPU 101 has the functions described below. Target hot air temperature setting information (T _C ) 63 based on the type and amount of dried grains output from the target hot air temperature setting knob 69 is fetched through the digital input circuit 59 and the input port 105, and the information is stored in a memory. Store in 103. The actual hot air temperature (T _B ) information 81 output from the hot air temperature detection sensor 79 is converted into the A / D conversion circuit 6
1, take in through the input port 107. The outside air temperature (T _A ) information 85 output from the outside air temperature detection sensor 83 is fetched through the A / D conversion circuit 61 and the input port 107. The temperature difference between the actual hot air temperature (T _B ) information 81 fetched in and the target hot air temperature setting information (T _C ) 63 fetched in is calculated using the formula T _C −T _B. The standard outside air temperature data at the time of initial combustion stored in the memory 103 is called and compared with the outside air temperature (T _A ) information given from the outside air temperature detection sensor 83. When the detected outside air temperature (T _A ) is extremely different from the above data as a result of the comparison in step 1, the rotation speed N _{F obtained} by correcting the fan motor rotation speed N with a preset basic correction rate α is further added with the correction rate β. / Set the subtracted rotation speed N _A, and set the fan motor 29 via the output port 108 and analog output circuit 113.
A drive command signal is output to a drive circuit (not shown).

The control operation of the above configuration will be described mainly with reference to the flowchart of FIG.

Prior to the start of the drying operation, the operator sets the target hot air temperature setting knob 69 on a predetermined scale according to the type and amount of the dried grains. When the CPU 101 recognizes that it is given from the operation information 67 related to ignition from the operation switch 15 (step 121), the CPU 101 proceeds to step 125 via step 123. The CPU 101 calls the on-time duration t ₁ of the control pulse signal at the time of initial combustion from the data stored in the memory 103 and sets it (step 125).

The CPU 101 calls the standard outside air temperature data stored in the memory 103, and calculates the rotation speed N of the fan motor 29 at the time of performing the initial combustion near the temperature (step 12).
7). When the CPU 101 recognizes that there is almost no difference between the outside air temperature detection value T _A acquired in step 129 and the data, it sets the fan rotation speed N to N _F and sets the on-time duration of the control pulse signal. Set t ₁ to a value commensurate with the above N _F. CPU101, the fan correction value N _A determined by the calculation of the N _F-beta = N _A when the value of the open rather large addition T _A of the said detection value T _A data is determined to belong to the low temperature region Set as rotation speed. CPU101 is N _F contrary to the above to when the value of the T _A is determined to belong to the high temperature range
The correction value N _A calculated by + β = N _A is set as the fan rotation speed (steps 131 and 133). The CPU 101 outputs a drive command signal to a drive circuit (not shown) of the fan motor 29 based on the fan rotation speed N _A set in step 133. Along with this, the CPU 101 sets the t ₁ so that combustion can be performed at an appropriate air-fuel ratio corresponding to the amount of combustion air supplied by the N _A , and outputs a control pulse signal to the drive circuit (not shown) of the electromagnetic valve 21. (Step 135). CPU
When 101 determines based on the T _B information given from the hot air temperature detection sensor 79 that it is safe to end the initial combustion, the process proceeds to step 139, and when it is recognized that the initial combustion needs to be continued, step 127 is performed again. (Step 137). By performing the initial combustion control of the drying device 1 in the process such as steps 127 to 137,
The following effects can be obtained. For example, as shown in FIG. 4, the on-time time width of the electromagnetic valve increases, and even if the on-time width is the same, there is a large difference in the fuel flow rate depending on the three temperature regions, the high temperature region, the standard temperature region, and the low temperature region. Can supply the combined amount of combustion air. FIG. 5 and FIG. 6 show the effects as described above. As shown in FIG. 5, in the conventional example, the temperature characteristics of the fan motor speed and the valve on-time time width, which are shown in the high temperature range, the standard temperature range, and the low temperature range respectively, are in accordance with the present invention. According to the embodiment, the correction is performed as a curve in the high temperature region and as a curve in the low temperature region. FIG. 6 shows the rotation speed correction of the fan motor as shown in FIG. 5 in relation to the valve on-time time width. In the conventional example, the correction factors respectively shown in the high temperature region, the standard temperature region and the low temperature region are corrected like a curve in the high temperature region and like a curve in the low temperature region by the embodiment according to the present invention.

When the CPU 101 finishes the initial combustion in step 137, it shifts to the normal combustion control thereafter (step 139-
Step 157). That is, the CPU 101 has the T _C setting information 69 and the T _B
The information 81 is read (steps 139 and 141), T _C −T _B is calculated (step 143), and the values of T _C and T _B are compared (step 145). When the CPU 101 recognizes that T _C = T _B in step 147, the combustion control is continued without changing the value of the set on-time time width T (step 15
9), when it is recognized that T _C ≠ T _B , the value of T is increased or decreased according to the difference between T _C and T _B (step 147). CPU101
During the drying operation, step 149 to step 139
The operation up to step 149 is repeated through. 8th
The figure shows the combustion control as described above using an analog circuit. That is, the analog output circuit described above
A circuit as shown in the figure is connected to the position 113, and the control pulse signal given from the CPU 101 to the above-mentioned valve drive circuit (not shown) is detected by the outside air temperature detection sensor 83.
It is corrected based on T _A and output to the fan motor 29. The waveform shaper 161 waveform-shapes the fuel supply amount control pulse signal supplied from the CPU 101, and then the pulse / voltage conversion circuit 163.
Output to. The pulse / voltage conversion circuit 163 converts the signal into a predetermined analog voltage signal. The buffer 165 receives the voltage signal, amplifies it, and outputs it to the inverting amplifier 169.
The inverting amplifier 169 corrects the signal at a predetermined correction rate as the pulse width of the control signal supplied from the CPU 101 changes, and outputs the corrected signal to the (−) side terminal of the adder 175. The temperature detector 171 amplifies the detection signal given from the detection sensor 83 and outputs it to the inverting amplifier 173 and the temperature correction amplifier 167, respectively. The inverting amplifier 173 level-converts the detection signal and outputs it. The temperature correction amplifier 167 amplifies and outputs the difference between the signal given from the pulse / voltage conversion circuit 163 and the signal given from the temperature detector 171. The adder 175 inputs a signal obtained by adding the signal supplied from the temperature correction amplifier 167 and the signal supplied from the inverting amplifier 173 from a (+) side terminal, and outputs the signal supplied from the inverting amplifier 169. And the difference is amplified and output to a drive circuit (not shown) of the fan motor 29.

Since the valve on-time time width and / or the fan motor speed is corrected in accordance with the detection signal given from the outside air temperature detection sensor 83 in the above-described configuration, the processing procedure as shown in FIG. It can be fully substituted.

As described above, according to the present invention, when it is determined that the detected outside air temperature belongs to the low temperature range outside the predetermined temperature range set in advance, the basic correction rate is corrected again by the predetermined parameter. Since the amount of combustion air supplied from the combustion air supply means is corrected by the ratio, it is possible to provide a drying device capable of performing stable initial combustion with an appropriate air-fuel ratio in a low temperature range of the outside air temperature.

[Brief description of drawings]

1 is an overall perspective view of a drying apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view of a burner combustion system used in the drying apparatus according to an embodiment of the present invention, and FIG. 3 is an illustration of the present invention. FIG. 4 is a block diagram according to an embodiment, FIG. 4, FIG. 5, and FIG. 6 are views showing comparison of data showing the effect according to one embodiment of the present invention and the effect according to the conventional example, and FIG. FIG. 8 is a diagram showing a flowchart of the configuration of FIG. 8 and FIG. 8 is a diagram showing an analog circuit used in the drying apparatus according to the embodiment of the present invention. 10 …… Microcomputer 19 …… Fuel supply pump 21 …… Fuel supply solenoid valve 29 …… Fan motor 83 …… Outside air temperature detection sensor

Claims (1)

[Claims] Claim: What is claimed is: 1. A means for providing a part of the outside air ventilation as a combustion air based on the outside air temperature detected by the outside air temperature detecting means as combustion air and a fuel supply system having a predetermined outside air ventilation amount and fuel flow rate. In a drying device that performs combustion control by controlling each of them so as to maintain the relationship, when the outside air temperature detected by the outside air temperature detecting means is within a predetermined temperature range set in advance, it is given from the combustion air supply means. The basic correction factor is corrected via a predetermined parameter when it is determined that the detected outside air temperature belongs to a low temperature region outside the predetermined temperature range while correcting the amount of fuel air to be set by a preset basic correction factor. The drying device is provided with a combustion air amount correction unit that corrects with a correction rate that is corrected again.