JPS5872872A - Control system of drying of circulation type cereal 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] This invention relates to a drying control system for a circulating grain dryer.

Circulating grain dryers, which are commonly used, set the hot air temperature empirically or based on a pre-prepared table, mainly using grain type, amount, initial moisture content, and outside air temperature as parameters. was.

However, this method of setting the hot air temperature does not take the length of the drying time into consideration, so there is an inconvenience that the drying time to reach the target moisture content varies greatly depending on the weather conditions on the day of operation. . Moreover, in combination with such fluctuations in drying time from day to day, the accumulation of downtime each time is large, which reduces the operating rate of the dryer, resulting in a reduction in drying efficiency.

In other words, even though this type of type has enough time to extend the drying time and dry at a low temperature, the initial temperature setting of the hot air is set high, resulting in the surplus power (play) of the machine. ) was dried at high temperatures, leaving behind residue.

However, considering the quality of the grain, it is desirable to stretch it for as long as possible and dry it at a low temperature.

The purpose of this invention is to be able to arbitrarily set the drying time so as to eliminate downtime, and thereby to set the hot air temperature to a low value, and furthermore, to reduce the drying time until the target moisture content is reached due to changes in outside temperature, etc. The purpose of the present invention is to provide a drying control method that matches the set time regardless of the time.

In accordance with the above object, the present invention detects the type, poison, and target moisture content of the grain, as well as the moisture content and outside temperature at that time, after starting drying at a predetermined hot air temperature and after a certain period of time has elapsed since the time when the predetermined moisture content has been reached. In addition, the remaining drying time (set drying time - elapsed time) is used as a parameter to reset the hot air temperature from a pre-stored table.

FIG. 1 shows a drying curve obtained by the control method according to the invention.

Time to is the initial time at the start of drying, and point a) at this time is obtained from the moisture meter as the initial moisture content. Time t. Then, the hot air temperature is set based on the type and amount of grain, the target moisture content (generally around 15φ) set in the input section, and the outside temperature. This setting is performed empirically or automatically by searching a table in which the correspondence between this information and the set temperature is stored in advance. After drying starts, when the drying temperature reaches a certain moisture content b (for example, 2 (around 1)) which does not significantly affect the quality even if the drying temperature is slightly higher, the hot air temperature is reset and the hot air temperature is corrected.

The hot air temperature is reset based on the type, amount, and target moisture content of the grain set in the input section at the start of drying, as well as the outside temperature and moisture content at time t1, and the elapsed time from the drying time set in the input section. This is done by searching a table that stores the correspondence between the information and the hot air temperature, using the remaining drying time after subtracting the drying time as a parameter. Since this information correlates with the hot air temperature necessary to reach the target moisture content at the end of the drying time To, t2, unless there is a sudden change in weather, the correspondence between this information and the drying temperature was memorized in advance. The optimum hot air temperature can be set using the table.

By performing the above control, drying can be completed as scheduled at time t2. Here, during time T□, the grain is in a high moisture state, so even if the drying temperature is slightly high, it does not have much of an adverse effect on quality, whereas during time T2, the grain is in a low moisture state. Therefore, it is desirable that the hot air temperature is low. On the other hand, in this control method, as mentioned above, the time '1
Since ゛o can be kept constant, the drying time is 1゛. can be set as the time for the next special train to start driving. That is, one hour'l is the period in which the drying temperature particularly affects the quality.
(2) can be made for a long time, and as a result, the hot air temperature can be set to a low temperature that is desirable for quality improvement.

In this way, when a certain moisture content is reached, the drying time To can be kept constant each time by automatically resetting the hot air temperature according to a predetermined table. Since it can be set to a long time for the next special start of operation, it is possible to gently dry at a low temperature for time 1 to 2.

In the above description, the hot air temperature is reset once during the process, but it may be set multiple times, or the time required to reset the temperature may be shortened as time passes. In this case, time accuracy is further improved.

Next, a grain dryer to which the control method according to the present invention is applied will be explained.

FIG. 2 is a block diagram of the dryer control circuit, and FIG. 3 is a flowchart showing the operating procedure of the dryer control circuit.

In FIG. 2, the control unit 1 includes a CPU 10, a battery-backed RAM II, a ROM 12, and a timer 13.
and Ilo, 14, 15. The RAM 11 is divided into an A parameter area that stores target moisture content, grain type, loading amount, drying time, outside temperature, and moisture content, a table area that stores a drying temperature calculation table, and other areas. . Each table associates the set temperature and oil amount according to the parameter amount, and these relationships are created in advance and stored in the RAM.A moisture content needle 3 is provided in the hopper of the dryer main body 2. Also, a temperature sensor 4 is provided outside to detect the outside temperature. The outputs of these sensor sections are then sent to A/D converters 5 and 6.
It is converted into a digital/I/quantity at , and is taken in to l1014 via multiplexer 7. In addition, the target moisture content setting volume 80, grain type setting volume 81, filling amount setting volume 82, and drying time setting volume 83 are set based on the oil amount set in the operation panel control section 1.
An electromagnetic control pulse is sent to the drive circuit 20, and the drive circuit 20 opens and closes the center of gravity according to this control pulse.

Next, the operating procedure of this control circuit will be explained.

' Figure 3 shows the drying control procedure.

In step no (hereinafter referred to as step ni) to step n3, each parameter set in the input section 8, grain target moisture content, grain type, filling amount, drying time is input.Furthermore, n , 4 * At n5, the outside temperature and initial moisture content are taken in from the sensor section. At n6, an appropriate drying temperature is set at the input section based on this information excluding the drying time, and this temperature is used as a control temperature for other drying devices. Next, perform electromagnetic pump drive control with conditions n9 or less at the time of the test.
IO is a procedure for determining the frequency of the electromagnetic pump necessary to keep the set hot air temperature constant.

n□1 is the moisture content b predetermined in the electromagnetic pump drive step
(See FIG. 1) The electromagnetic pump is driven until reaching the point (see FIG. 1). This electromagnetic pump is driven to open and close by a pulse signal based on the data set at n1o, and is once closed when moving from n1□ to n13.

Subsequently, at n13 + n14, the time t when the water content reaches
1 (see Figure 1) are re-measured, and this information and the drying time T set in n3 are remeasured. Time elapsed since T
Calculate the drying rate from the remaining time after subtracting 1, and use this drying rate and the information obtained from no-n2 as parameters to calculate n
16 e In n17, hot air temperature data to be reset is read from the hot air temperature calculation table with reference to these parameters, and in n17, it is set in another register as the control temperature. The electromagnetic pump is driven until the target moisture content is reached, and when the target moisture content is reached, the process proceeds from n21 to n22 and the electromagnetic pump is closed.

By extending the drying time To until the start of the next operation using the above control, the idle time until the start of the next operation, which conventionally occurs, is used as drying time, and as a result, the hot air temperature during drying becomes The hot air temperature can be reduced by 4 degrees compared to conventional high-temperature drying (50℃ to 60℃).
This made it possible to dry at low temperatures, such as 0°C, and significantly improve the quality of grain. Furthermore, up to a predetermined moisture content (for example, 20 coefficients), the hot air temperature is set only under the initial conditions, and in order to reset the conditions once the predetermined moisture content is reached, the generally speaking approximately 20 coefficients are set. Satisfactory quality can be obtained if we take into account the physical and physiological changes in the grain that occur at the grain boundary and the errors in the moisture meter. Furthermore, according to the present invention, each time the operation is stopped can be made relatively short, so there is an advantage that the operating rate of the dryer can be increased and the efficiency can be improved.

[Brief explanation of the drawing]

FIG. 1 shows a drying curve obtained with the control method according to the invention. FIG. 2 is a block diagram of a dryer control circuit to which the control method according to the present invention is applied, and FIG. 3 is a flowchart showing the operating procedure of the control circuit. ■...Control unit, 3...Moisture quick meter, 4.
...Temperature sensor, 8...Input section. Applicant: Akira Tatsumoto, Patent Attorney Hisao Komori

Claims (1)

[Claims] 1. It has an input section for grain type, amount, target moisture content, drying time, current moisture content, and a timer that stores the elapsed time.
When a certain moisture content is reached after drying is started at a predetermined hot air temperature, hot air is supplied from a table stored in advance using information from the input section and sensor section, and the remaining drying time obtained by subtracting the elapsed time from the drying time as a parameter. A drying control method for circulating grain dryers that resets the temperature.