JPS6352306B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a grain dryer that dries grain by exposing it to hot air from a burner.

(Prior art) When drying with this type of grain dryer, when the outside air temperature is high, the heating charge of the burner must be reduced compared to when it is low, and the calorific value of the burner, that is, the temperature at which the outside air is heated by the burner, must be reduced. If the grain temperature becomes too high, the grain becomes overly dry and cracks occur.

(Problem to be solved by the invention) However, when drying a small amount of grain by loading it into a large-capacity grain dryer, the fuel in the burner is initially restricted and burned, so it is necessary to further restrict the fuel. It is not possible to reduce the fuel below the rated flow rate of the burner, as this will cause poor combustion in the burner.
In such a case, there is a problem in that when the outside temperature becomes high, an overdry state cannot be avoided.

The present invention solves this inconvenience, and when the hot air temperature still exceeds the set value even if the burner is fired at the minimum value of the rated flow range, the hot air is released to the outside of the machine. The purpose is to prevent the temperature from becoming too high.

(Means for solving the problem) In order to achieve the above object, the present invention has the following configuration.

That is, the present invention includes: a regulating valve that opens and closes a hot air outlet by opening a hot air outlet in a shielding plate that partitions a hot air chamber and an air exhaust chamber of a grain dryer; and a control valve that measures the temperature of outside air. It has an outside air temperature sensor and a hot air temperature setting means that sets the hot air temperature of the burner according to the amount of grain loaded into the grain dryer, and the temperature difference between the set hot air temperature and the measured outside air temperature. is determined, and when the temperature difference is less than the lower heating limit temperature of the burner, the regulating valve is opened and the currently set hot air temperature is corrected to the sum of the measured outside air temperature and the lower heating limit temperature. It becomes.

(Function) The present invention determines the temperature difference between the hot air temperature of the burner set by the hot air temperature setting means and the outside air temperature measured by the outside air temperature sensor.

For example, when the outside air temperature is high and the temperature difference is below the lower heating limit temperature of the burner, the regulating valve is opened to directly discharge the hot air from the hot air chamber to the outside of the machine without passing through the drying chamber. At the same time, the currently set hot air temperature of the burner is corrected to the sum of the measured outside air temperature and the burner heating minimum temperature to maintain normal combustion of the burner.

(Embodiment) The present invention will be explained based on the embodiment shown in the drawings. Reference numeral 1 refers to a storage chamber of a dryer, and a chevron plate 2 having an inverted V-shaped cross section is provided at the center of the bottom of the storage chamber. Install boards 3 and 3. Perforated plates 4 are connected to both side edges of the chevron-shaped plate 2 and the lower edges of the guiding swash plates 3, 3, respectively, and a pair of opposing perforated plates 4 form a drying chamber 5, 5.

The discharge ports at the lower ends of the drying chambers 5, 5 are connected to a gutter-like grain collection chamber 7 through a rotary valve 6, and the delivery end of a grain helix 8 suspended horizontally in a groove in the center is connected to a grain raising machine. Connect to the lower intake port of 9. 10 is grain raising machine 9
Shows the loading port that communicates with the lower intake port.

A grain feeding helix 11 is connected to the upper part of the grain raising machine 9,
Its terminal end is opened above the diffusion plate 12 suspended from the center of the ceiling plate of the storage chamber 1.

Then burner 1 is placed opposite the front and back of the dryer.
3 and a suction fan 14 are attached, and the burner 13 is exposed to the hot air chamber 15 inside the left and right drying chambers 5, 5, and the fan 14 is attached to the outside of the drying chambers 5, 5 and the exhaust area surrounded by the outer wall of the dryer. Connect to the wind chamber 16.
A shield plate 17 closes the side of the hot air chamber 15 opposite to the burner 13 and partitions the hot air chamber 15 and the exhaust chamber 16.

The grains are passed through a loading port 10 through a grain raising machine 9 and a grain feeding helix 11, are evenly loaded into a storage chamber 1 by a diffusion plate 12, and flow down a drying chamber 5. At this time, the hot air from the burner 13 enters the left and right drying chambers 5 from the central hot air chamber 15, dries the grains flowing down, and the exhausted air containing moisture passes through the exhaust chamber 16 and is discharged outside the machine by the fan 14. The grains after exhaustion and drying fall into the grain collection chamber 7 by rotation of the rotary valve 6, return to the storage chamber 1 again by the grain removal screw 8 and the grain raiser 9, and repeat this process.

In this embodiment, a hot air outlet 18 is opened in the shielding plate 17 facing in front of the fan 14, and a regulating valve 19 which can be opened and closed is attached to the outlet. 20 is regulating valve 1
The rotation support shaft 9 is integrally connected along the upper side of the regulating valve 19, and both ends thereof are rotatably attached to the plate surface of the shielding plate 17, and one end of the rotation support shaft 20 is bent diagonally downward. The tip of the operating rod 22 of the solenoid 21, which is fixed to the plate surface of the shielding plate 17, is brought into contact with the bent portion.

Next, the hot air temperature setting circuit 23 is connected to the appropriate outside air temperature calculation circuit 24, and its output side is connected to the input side of the comparator 26 together with the outside air temperature sensor 25 that measures the outside air temperature. The solenoid 21 and the fuel flow control valve 28 of the burner 13 are connected via the amplifier 27 .

29 is a hot air temperature correction circuit, to which an outside air temperature sensor 25 and an amplifier 27 are connected to the input side;
The output side is connected to the hot air temperature setting circuit 23.

Then, the set temperature Ta of the hot air is determined and set by the setting circuit 23 according to the amount of grains to be dried.
The appropriate outside temperature Tb is calculated from Ta and the lower heating limit temperature t of the burner 13 according to the following formula.

Tb=Ta−t (1 equation) Here, the lower heating limit temperature t is the temperature at which the burner heats the outside air when the fuel supply flow rate to the burner is set to the minimum value within the rated flow rate range of fuel that allows the burner to burn normally. This refers to the heating temperature, and its value is determined by the type of burner used.

And the appropriate outside air temperature Tb and the outside air temperature sensor 25
The comparator 26 compares the actual outside air temperature Tc with the outside air temperature Tc, and if the value of the appropriate outside air temperature Tb is the same as or smaller than the outside air temperature Tc (Tb≦Tc), the comparator 26 outputs an activation signal to activate the solenoid. 21 is energized and the operating rod 22 is pushed out. As a result, the pivot shaft 20 rotates, the regulating valve 19 opens, and a portion of the hot air from the burner 13 passes directly from the hot air chamber 15 through the discharge port 18 without passing through the drying chamber 16 and is discharged to the outside of the machine. .

At the same time, an activation signal from the comparator 26 is output to the fuel flow control valve 28, and the flow rate of fuel supplied to the burner 13 is throttled to the minimum value within the rated flow range.

Further, the hot air temperature correction circuit 29 is activated by the activation signal of the comparator 26, and the hot air temperature setting circuit 23 is corrected from Ta to Tc+t.

For example, when drying a minimum amount of 8 stones of paddy in a dryer with a loading capacity of 8 stones to 24 stones and a minimum heating temperature t of the burner of 10℃, the set temperature Ta of the hot air is
If the outside air temperature Tc is 28°C at 34°C, the appropriate outside temperature Tb is 24°C from (Equation 1), and the outside air temperature Tc = 28
Since the flow rate is small compared to .degree. C., the comparator 26 outputs an activation signal, the regulating valve 19 opens, and the burner fuel is throttled to the minimum flow rate. Then, the hot air temperature correction circuit 29 corrects the hot air temperature setting Ta=34°C in the hot air temperature setting circuit 23 to Ta=Tc+t=28°C+10°C=38°C.

As a result of the correction, the output Tb of the appropriate outside air temperature calculation circuit 24 is the actual outside air temperature Tc = 28℃ according to (1 equation)
, the comparator 26 continues to output an activation signal, the regulating valve 19 remains in the open position, and the burner continues to burn normally with the minimum flow of fuel.

Instead of automatically opening and closing the regulating valve 19 in this way, a temperature indicator is connected to the outside air temperature sensor 25 to read the outside air temperature Tc, and the difference between that value and the hot air set temperature Ta is calculated as follows: Tc≦t (Equation 2) If the lower heating limit temperature t of the burner is below the value, that is, the lower heating limit temperature t of the burner is the set temperature of the hot air.
If the difference between Ta and the outside temperature Tc is exceeded, manually close the solenoid 21 switch, open the regulating valve 19, and at the same time reduce the fuel flow regulating valve 28 to the minimum, and set the setting element (for example, potentiometer) of the hot air temperature setting circuit 23. Manually operate the hot air temperature
It may be increased from Ta to Tc+t.

Note that a forward/reverse motor may be used instead of the solenoid 21 to open and close the regulating valve 19.

(Effect of the invention) In short, in the present invention, when the temperature difference between the set hot air temperature and the measured outside air temperature is lower than the lower heating limit temperature of the burner, the regulating valve is opened to direct the hot air from the hot air chamber through the drying chamber. In addition, the currently set hot air temperature is corrected to the sum of the measured outside air temperature and the burner's lower heating limit temperature, so the burner fuel is throttled and the heating temperature is lower than the lower limit temperature. It is no longer necessary to lower the grain temperature to a lower temperature, it is possible to prevent the grain temperature from rising excessively while the burner is burning normally, and it is possible to finish drying high-quality grain without shell cracking even when the outside temperature is high. .

[Brief explanation of the drawing]

Fig. 1 is a vertical front view of the entire grain dryer embodying the present invention, Fig. 2 is a cross-sectional plan view taken along the - line, Fig. 3 is an enlarged perspective view of its main parts, and Fig. 4 is its control system. FIG. 13 is a burner, 14 is a suction fan, 15 is a hot air chamber, 16 is an exhaust chamber, 17 is a shielding plate, 18 is a hot air outlet, 19 is a regulating valve, and 21 is a solenoid.

Claims (1)

[Scope of Claims] 1. A regulating valve that opens and closes a hot air outlet by opening a hot air outlet in a shielding plate that partitions a hot air chamber and an exhaust air chamber of a grain dryer, and measures the temperature of outside air. and a hot air temperature setting means for setting the hot air temperature of the burner according to the amount of grain loaded into the grain dryer, and the temperature between the set hot air temperature and the measured outside air temperature. Find the difference, and when the temperature difference is below the lower heating limit temperature of the burner, open the regulating valve and correct the currently set hot air temperature to the sum of the measured outside air temperature and the lower heating limit temperature. A hot air discharge device for a grain dryer.