JPS5929794B2 - Grain dryer burner combustion amount control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the hot air temperature of a grain dryer, and more particularly to a burner combustion amount control device for a grain dryer that is highly versatile and can be used in a wide range of applications from large machines to small machines. .

Grain dryers are manufactured in a variety of different sizes, from large to small, in order to meet the various demands of consumers.

Naturally, with the aim of facilitating design and manufacturing and reducing manufacturing costs, each component is made as common as possible from large to small machines.

However, if we try to share the same device for controlling the temperature of hot air sent to the drying section of grain dryers, a device that exhibits ideal temperature control characteristics in a large machine with a large air volume will not work in a small machine with a small air volume. , rapid temperature changes are repeated, and the hot air temperature curve becomes sharply up and down, as shown by the thin line in Figure 7, curve C2, which not only makes the user feel unnecessarily anxious, but also makes it difficult to perform stable drying. This is not desirable.

The above-mentioned disadvantage is that the minimum amount of oil that can be controlled by an oil pump, that is, the minimum flow rate control amount, is unique to the pump and is constant, and as a result, the minimum temperature control amount is inversely proportional to the air flow rate. It arises from making a single decision.

In other words, in the case of a large machine, the minimum temperature control amount is 0.5°C in this example, but in the case of a small machine, since the air volume is small, the minimum temperature control amount is 0. .7℃
This is because it will rise.

Therefore, in the case of a small aircraft with a small air volume, the temperature rises and falls rapidly, resulting in repeated violent pulsations.

In addition, the waiting time until the hot air temperature sensor, which is a hot air temperature sensor, detects the temperature, controls the pump, and the hot air temperature changes, that is, the response delay (in this example, it takes about 50 seconds, so the above The inconvenience increases.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to realize a burner combustion amount control device for a grain dryer that can be used widely from large machines to small machines and can obtain ideal temperature control characteristics.

The present invention will be explained below based on the illustrated embodiments.

In FIGS. 1 and 2, a grain dryer 1 has a storage section 2, a drying section 3, and a grain collection section 4, and lifts grains put into a hopper 6 of a grain lifting machine 5, and upper conveying means 7. The grains are conveyed to the upper central part of the dryer 1, dropped evenly into the storage section 2, guided through the drying section 3 to the grain collecting section 4, and transported to the lower part of the grain lifting machine 5 by the lower conveying means 8. The grain is then lifted again by the grain lifting machine 5, and the cycle is repeated to dry the grain.

The drying section 3Vc needs to supply a predetermined amount of hot air at a predetermined temperature.

Therefore, a hot air generator 9 is provided in front of the drying section 3,
An exhaust fan 10 is provided on the rear surface.

Further, a control panel 11 is provided at the front of the hot air generator 9.

The exhaust fan 10 is provided with an exhaust fan motor 48, which will be described later, the grain lifting machine 5 is provided with a conveyor motor 49, and the grain collecting section 4 is provided with a circulation motor 51 for driving a feeding valve.

The exhaust fan motor 48 is used to drive an exhaust fan, and is a convertible motor with the number of poles, and can be switched between 4 poles and 8 poles (or 4 poles and 6 poles).

The conveyor motor 49 is connected to the grain lifting machine 5 and the upper conveyor means I.
It is for driving.

A geared motor (electric motor with gears) is used as the circulation motor 51, and the circulation speed can be changed by controlling on/off.

Further, 22 is a moisture meter that automatically measures the moisture content of grains.

FIG. 3 shows the control panel 11, which includes an OK monitor display 40 that displays the operating status of each part of the dryer, an operation switch 25, a stop switch 26, a stop water price setting switch 23, a grain amount setting switch 24, and a numerical display. It has a container 41 etc.

The hot air generator 9 includes an evaporative oil burner 12 in a casing 9a of the hot air generator, as shown in an enlarged sectional view in FIG.
A combustion cylinder 13 is installed horizontally above the burner.

Note that 14 is a primary air fan, 47 is a motor for driving the fan, and 16 is an oil pan for collecting waste oil and overflow oil.

A pump 46 is used to feed oil from the oil tank 18 to the burner 12. It uses a plunger pump and is configured to be driven by an electromagnetic drive device.

A hot air temperature sensor 21 is a hot air temperature sensor made of a thermoelectric conversion element such as a thermistor, and outputs a hot air temperature signal to a temperature control circuit 19a, which will be described later.

Next, the principle of the control circuit 19 communicating with the temperature control circuit 19a to control the temperature control circuit 19a will be explained with reference to the block diagram of FIG.

In the figure, 20 is an outside air temperature sensor.

Reference numeral 27 denotes a model selection switch, which is provided in the control panel 11 and is used to select and switch in advance according to models with different air volumes. can.

28 is a group of various safety switches, such as a fire extinguisher activation switch, a grain lifting machine safety switch, and a fuel overflow switch.

29 is a clock oscillator, which is a device that generates a synchronizing signal in order to synchronize the operation of each part; 30 is an A/D conversion circuit, which is a circuit that converts the analog information signal from the outside temperature sensor 20, etc. into a digital signal. , 31 is an encoder that encodes the set values from the stop moisture value setting switch 23 and the grain amount setting switch 24 and outputs the encoded values to an input data buffer 34 to be described later.

Reference numeral 32 denotes a timer interrupt control circuit, which includes a timer circuit whose time can be set by a command from an arithmetic processing unit (hereinafter referred to as CPU) 350, which will be described later, and a circuit which issues an interrupt command to the CPU 35 to indicate completion of the timer operation.

33 is an interrupt control circuit, which controls the A/
A circuit that issues an A/D conversion start command to the D conversion circuit 30;
/D conversion processing completion circuit for issuing an interrupt command to the CPU 35.

34 is an input data bath sofa, and the A/D conversion circuit 30
, encoder 31, various switches 25, 26, 27
, 28, etc., to an input data bus 53, which will be described later, according to instructions from the CPU 35.

35 is a processing unit (CPU), which is a device that performs storage, calculation, and control functions.

36 is a display control circuit, which includes a decoder for decoding output data etc. sent from the CPU 35 via an output data bus 55, which will be described later, and an OK momo display 40 and a numeric display 4, which will be described later.
1 and a driver that operates the 1.

Reference numeral 37 denotes an output data bus 55, which has a register function for temporarily storing output data sent from the CPU 35 via an output data bus 55, which will be described later, in response to a command sent from the same CPU 35 via a control signal line 54, which will be described later. .

38 is read-only memory (fixed storage device, ROM)
), the CPU operates according to a program stored in advance in the ROM 3B.

A random access memory (RAM) 39 is a readable/writable memory that temporarily stores the calculation results of the CPU 35 and input data.

Each of the above-mentioned devices shown surrounded by a dashed line in FIG.
The CPU 35 has a function as a control microcomputer.

Further, 40 is an OK monitor display, which displays the safety state of the dryer.

41 is a numerical display which digitally displays the moisture content of the grain measured by the moisture meter 22 and the hot air temperature alternately.

42 is a burner drive circuit, and 43 is a motor drive circuit, which drive the respective loads according to data from the output data buffer 37.

That is, the burner drive circuit 42 controls and drives the ignition heater 44, the ignition valve 45, the pump 46, and the burner fan motor 47.

Further, the motor drive circuit 43 controls and drives an exhaust fan motor 48, a conveyor motor 49, a dust remover motor 50, a circulation motor 51, and a moisture meter motor 52.

In this embodiment, the pump 46 is a reciprocating pump such as a plunger pump that is electromagnetically driven, and as described later, the plunger of the pump is driven by a pulse signal.
The method is to control the amount of oil fed by proportionally changing the width of the pulse signal, but it is also possible to control the amount of oil fed by changing the frequency of the pulse signal to change the drive cycle of the plunger. good.

FIG. 6 shows the operation of the control device more specifically using a flowchart.

First, when the operation switch 25 shown in Fig. 5 is turned on, the RO
The M38 program starts and the drying starts 1 in Figure 6.
00, and the various motors 48 to 52 start operating.

Next, according to the program in the ROM 38, the burner drive circuit 42 shown in FIG. The motor 47 is driven to enter the state of burner ignition 101 shown in FIG.

102 compares the grain moisture value obtained from the moisture meter 22 in FIG. 5 with the set value of the stop moisture value setting switch 23, and if the moisture value does not reach the set value, the process proceeds to 103, where the moisture value is set. When the value is reached, the process proceeds to 117.

117 is burner extinguishing, and the burner drive circuit 42 performs a series of operations to extinguish the burner 12. At 118, various motors are stopped, and the drying end state 119 is reached.

103 is an input of the hot air temperature Tb, which is a routine that proceeds when the moisture value does not reach the set value, and the hot air temperature Tb is input from the hot air temperature sensor 21.

Next, calculation of the set temperature Tc at 104 is performed based on signals from the outside air temperature sensor 20, the hot air temperature sensor 21, the moisture meter 22, and the grain amount setting switch 24, and the set temperature Tc is
c is determined.

105 is a judgment that 1Tc-Tbl≦1, and the reading value is 1.
In other words, if the temperature difference is ±1° C. or more for a dog, the process branches to 120, and if it is less than ±1° C., the process proceeds to 106, where oil is fed for the pulse width Tw determined in the previous routine.

The routine starting from 120 is a program for increasing 121 or decreasing 122 the amount of oil fed.

At 120, Tc-'rb>o is determined, and if the answer is yes, the process branches to 121, and if the answer is no, the process branches to 122.

That is, if the hot air temperature Tb is too high than the set temperature Tc, the amount of oil fed is decreased, and if the hot air temperature Tb is too low, the amount of oil fed is increased.

That is, if Tb is too high, 'l' at 122
Determine c+4≧Tc+1.

If Tb is more than 1°C and 4°C or less than Tc, the process proceeds to step 125 and the pump drive pulse width Tw is changed to Δ
The pulse width is decreased by τ (minimum variable pulse width), and the stroke of the pump 46 is proportionally decreased by the pulse width, thereby reducing the amount of oil delivered.

If Tb>Tc+4, the flow advances by 126Vc, and the pump drive pulse width Tw is decreased by 2Δτ, thereby greatly reducing the oil supply amount.

And again, if Tb is too low, proceed to 121 and Tb
It is determined that c-1>Tb≧Tc-4, and if yes, advance by 124 VC and increase the pump drive pulse width Tw by Δτ.

If it is NO, go to 123 and change the pulse width Tw by 2Δ
Increase by τ.

(See FIG. 8) In other words, the degree of increase/decrease correction of the oil supply amount is changed depending on the extent of the difference from the set value.

Then return to the original main program. 107 corresponds to the switching contacts A and BK of the model selection switch 27 in FIG.
Branches to 08,109.

Switching contacts A and B correspond to large and small machines, respectively.
TI if switched to H, T2 if switched to H
, are respectively set in the sampling timer Ts on the program stored in the RAM 39.

In this embodiment, TI is set to 10 seconds in the case of B, and T2 is set to 15 seconds in the case of B.

Next, at 110, the pump 46 of FIG. 5 is driven, and at 111
The burner fan motor 47 is controlled at 112, the conveyor motor 49 and the dust ejector motor 50 are controlled at 112, the exhaust fan motor 48 is controlled at 113, and the circulation motor 51 is turned on and off at 114.

At step 115, it is checked whether the various safety switches 28 are operating.

If there is an inconvenience here, the process branches to 130 to display that fact on the OK monitor display 40, and at 131 calls an error handling subroutine and proceeds to the subroutine.

If there is no problem, it is checked in step 116 whether or not the sampling timer Ts has timed out, and if the sampling timer Ts has not timed out, the program runs again.
Jump to 110 in the flowchart and repeat this routine until Ts exceeds the set time.

Then, when the time is over, 102 of the flowchart
Jump to and repeat this routine starting with checking the moisture value.

When the moisture value finally reaches the set value, the drying process is completed through the above-mentioned procedure.

If control is performed using the configuration as described above, the following effects will be obtained.

When the model changeover switch 27 is switched to a large model, the sampling timer Ts is set to 10 seconds (that is, the oil supply amount is corrected every 10 seconds), and in this case, the pump drive curve A1 is as shown in Figure 7. Become.

In addition, the set temperature is set within ± above and below, as shown by diagonal lines in Figure 7.
This is a temperature range with a width of 1°C.

In the case of a large machine, the hot air temperature curve depicts the characteristic A2 shown by the solid line in FIG.

If this pump drive curve A1 is to be applied as is to a small machine with a small air volume, the hot air temperature curve will exhibit characteristics such as 02 in FIG.

With this characteristic, the fluctuation of the hot air temperature relative to the set temperature is greater than in a large machine, resulting in problems such as pulsation of the burner flame.

However, in the present invention, in the case of a small machine, the sampling period can be changed to 1 by changing the model selection switch 27.
5 seconds, that is, the oil supply amount correction operation cycle is made longer, and as a result, the pump drive curve becomes something like B1, and the hot air temperature curve B2 is almost the same as the temperature curve A2 shown by the large machine. It is possible to obtain temperature characteristics without the above-mentioned disadvantages.

In the above embodiment, the oil supply amount is corrected every sampling period of the hot air temperature, and the number of times per unit time, that is, the frequency of the sampling operation and the oil feed amount correction operation are matched, and the sampling is completed. The program is simplified by configuring the program to always take a corrective action when necessary.

However, there is no necessity to match the number of sampling times and the number of corrections.

The aim of the present invention is to change the correction operation cycle and regulate the oil supply amount by simply changing the switching means such as the model selection switch 27, and to make other parts of the program common, allowing for small air volume. The aim is to obtain approximately the same hot air temperature control characteristics for both a small machine and a large machine with a large air volume.

In addition, in the above embodiment, when the machine is used for only two types of machines, a large machine and a small machine, the sampling cycle is determined by the air volume, that is, the correction cycle for the oil supply volume. Of course, by adding more contacts and preparing an oil flow rate correction cycle, which is a sampling cycle determined by the air volume of the corresponding model, it is possible to realize a control device that can be applied to many different models. It is.

Furthermore, it can be applied to the same model when changing the air volume during drying, or to dryers other than circulation type.
Get the same effect.

As is clear from the above embodiments, according to the present invention, the following effects can be obtained.

(1) We have realized a burner temperature control device that has a configuration that changes the cycle of the oil supply amount increase/decrease correction operation in proportion to the amount of hot air, so it can be commonly applied to multiple models or the air volume reduction process can be performed with a single model. Approximately the same hot air temperature characteristics can be achieved even when applied to a device that has the same temperature characteristics.

(2) Furthermore, according to the present invention, it is possible to apply the control program stored in the memory circuit to a plurality of dryers with different amounts of hot air by simply changing the correction operation cycle of the amount of oil supplied, and the program development and specifications Changes and design changes become easier;
In this respect as well, it is highly versatile.

(3) Furthermore, if the processing device and control device are configured based on an integrated circuit microprocessor, the structure can be configured without using mechanical cams, contacts, etc., and the burner temperature control is small and highly reliable. The device can be realized.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a front view of the dryer, FIG. 2 is a side view, and FIG. 3 is an enlarged view of the control panel.
Fig. 4 is a cross-sectional side view of the hot air generator, Fig. 5 is a block diagram of the control device, Fig. 6 is a flowchart explaining the operation of the control device, and Fig. 7 shows the relationship between the pump drive curve and the hot air temperature curve. The graph shown in FIG. 8 is a graph showing the relationship between the pump drive pulse width Tw and the pump oil supply amount. Explanation of main symbols, 1 is grain dryer, 12 is burner, 1
9 is a toma circuit, 35 is an arithmetic processing unit (CPU), 38 is a read-only memory (fixed storage device, ROM), 3
9 is a random access memory (uniform speed memory, RAM), and 46 is a pump.

Claims (1)

[Claims] 1. A hot air temperature detector that detects the temperature of hot air in a grain dryer that generates hot air using an oil burner to dry grain;
A data storage unit that stores in advance data indicating a set temperature of hot air and data indicating a plurality of oil supply amount correction cycles, and a system that counts the difference between the set temperature and the detected temperature and supplies oil according to the size of the temperature difference. a processing device that determines the amount increase/decrease correction and selectively extracts the plurality of oil supply amount correction cycles from the data storage section; 1. A burner combustion amount control device for a grain dryer, comprising: a control device that outputs an oil feeding command of an amount corrected to increase or decrease based on the determination at each oil feeding amount correction cycle. 2. The burner combustion amount control device for a grain dryer as set forth in claim 1, wherein the processing device and the control device are mainly configured with a microprocessor formed into an integrated circuit.