JPS6338635B2 - - 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 with hot air.

(Prior art) Conventionally, as a grain dryer, an automatic moisture content meter is used to measure the moisture content of the grains being dried, and when the grains are dried to a predetermined finishing moisture content, the automatic moisture content meter issues a stop signal. There is a device that automatically stops the drying operation by outputting the following.

In such dryers, if the automatic moisture content meter malfunctions during drying operation and the automatic stop mechanism does not work, this could lead to overdrying or a fire hazard.
If the automatic moisture content meter malfunctions, the drying operation is immediately stopped to ensure safety.

(Problem to be solved by the invention) However, if the operator happens to be far away from the dryer and does not notice that the dryer has stopped due to a failure of the moisture content meter, the grains in the dryer may Since the product is left stationary and in a high humidity state without drying, it causes problems such as stuffiness and uneven drying.

Therefore, an object of the present invention is to dry grains with high quality without causing stuffiness or uneven drying even if the automatic moisture content meter breaks down during drying.

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

That is, the present invention provides a grain dryer that measures the moisture content of grains during drying using an automatic moisture content meter, and outputs a stop signal to automatically stop drying operation when drying to a predetermined finished moisture content. a failure determining means for determining whether the automatic moisture content meter is malfunctioning; and when the automatic moisture content meter is determined to be malfunctioning;
a remaining drying time estimating means for estimating the remaining drying time until drying of the grains stops from each value of the moisture content at the time of failure occurrence, a predetermined finishing moisture content set in advance, and a drying curve; and the automatic moisture content meter. When it is determined that there is a failure,
An automatic stop comprising a time measuring means for starting time measurement, and a drying operation stopping means for stopping the drying operation when the measured time reaches a predetermined time before the expiration of the estimated remaining drying time. Device.

(Function) When a malfunction occurs in the automatic moisture content meter during drying of grains in a grain dryer, the remaining drying time estimating means calculates each value of the moisture content at the time of failure and the predetermined finishing moisture content. , and the drying time until grain drying stops from the drying curve.

On the other hand, simultaneously with the occurrence of a failure in the automatic moisture content meter, the time measuring means starts measuring time.

When the measured time reaches a certain time before the expiration of the remaining drying time estimated as described above, the drying operation stop means stops the drying operation of the grain dryer.

(Example) The present invention will be described based on an example shown in the drawings. Reference numeral 1 denotes a conditioning chamber of a dryer, and a resistance type automatic moisture content meter A is attached to the wall of the dryer.

A drying chamber 2 communicates with the bottom of the tempering chamber 1 and is formed by two parallel perforated plates 3.

Then, the grains put in the conditioning chamber 1 gradually flow out into the drying chamber 2, and the surface of the grains is strongly dried by the hot air from the burner 4 that crosses the drying chamber 2 on the way.

After the hot air from the burner 4 crosses the drying chamber 2, it is discharged to the outside of the machine by a suction exhaust fan 5.

Rotate the rotary valve 6 at the lower end of the drying chamber 2 slowly to discharge the dried grains to the bottom of the machine, and transport them to the grain collecting helix 7, elevator 8 and grain feeding helix 9.
It is returned to the upper part of the conditioning chamber 1 via the .

While the grains are thus circulated, the moisture inside the grains is diffused to the surface in the conditioning chamber 1, thereby uniformly drying the entire grains.

In the present invention, the measurement data output terminal a and the failure detection signal output terminal b of the automatic moisture content meter A are connected to the central processing unit (CPU) 10 of the microcomputer.
Connect to. Reference numeral 11 indicates an A/D converter, 12 indicates various operation switches such as charging, drying, and discharge, and 13 indicates a finishing moisture content setting switch. On the output side of the central processing unit 10, there are installed a motor 15 for driving the elevator 8 and spirals of the dryer, a pump 16 for supplying fuel to the burner 4, a valve 17 installed in the fuel system, and a heater 18 for igniting the burner 4. Each is connected via an amplifier 14. Reference numeral 19 is a digital display that displays hot air temperature, moisture content, and remaining drying time, which will be described later.

Next, an example of the operation of the embodiment of the present invention configured as described above will be explained with reference to the flowchart of FIG.

Now, if you press the drying switch of the operating switches 12 to close it, the ignition flag will be set to 0 in the central processing unit 10, and the setting switch 1 will be set in advance.
3, the value of the finished moisture content (for example, 13% in the case of paddy) is read into the memory of the central processing unit 10. Then, the motor 15 starts, and then the ignition heater 18 generates heat and ignites the burner 4, and the ignition flag is set to 1. After ignition, burner 4
Hot air is sent in while controlling the fuel so that the temperature of the hot air remains constant, and the grains are circulated and dried inside the machine as described above.

During drying, the automatic moisture content meter A is operated periodically to measure the moisture content of the grains, and the value is displayed on the digital display 1.
Display on 9.

During the period in which the measured moisture content exceeds the finished moisture content and drying has not yet reached the finished state, the drying process is performed based on the measured moisture content, finished moisture content, and the drying curve shown in Figure 4. From that point on, the time required to complete the drying, that is, the remaining drying time is estimated, and this is displayed on the display 19.
Displaying the remaining time in this way has the advantage that it is easier for the operator to plan the operation of the dryer.

However, the automatic moisture content meter A malfunctioned, and its terminal B
When it is detected that a failure detection signal indicating a failure has been output, measurement of elapsed time is started from the time the signal is output. Then, when this elapsed time becomes equal to the time obtained by subtracting a certain time t (for example, t = 1 hour) from the remaining drying time estimated as described above, that is, when the certain time t is before the scheduled finishing time, burner 4 is turned on. The fire is extinguished and the motor 15 is also stopped. In other words, even if automatic moisture content meter A breaks down, drying operation continues until a certain period of time before the scheduled finishing time.

(Effect of the invention) In this way, in the present invention, when automatic moisture content meter A malfunctions during drying operation, the remaining drying time at the time of failure is estimated, and the remaining drying time is estimated until a certain time before the expiration of the remaining time. Since the drying operation continues and the drying operation is stopped only after the grain has been dried to a state on the verge of finishing, even if the operator uses an automatic moisture content meter
Even if the malfunction is not noticed, there is no risk of grain swelling or uneven drying as in the conventional method, and the quality of the grain is improved. In addition, restarting the drying operation after an interruption takes only a short time, so even if restarting the operation is delayed, drying can be completed quickly and efficiently.Also, the restarting operation can be done by blowing in outside air with a fan while the burner is extinguished, making it possible to ventilate the drying process quickly. Drying alone can be sufficient to complete the drying process, and it also has the effect of being economical.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional front view of a circulating grain dryer embodying the present invention, Fig. 2 is a cross-sectional plan view taken along the - line, Fig. 3 is a block diagram of an embodiment of the present invention, and Fig. 4 is a drying curve. The graph in FIG. 5 is a flowchart of an embodiment of the present invention.

Claims (1)

[Scope of Claims] 1. A grain dryer that measures the moisture content of grains during drying using an automatic moisture content meter, and outputs a stop signal to automatically stop drying operation when the grains are dried to a predetermined finished moisture content, a failure determining means for determining whether or not the automatic moisture content meter is malfunctioning; and when it is determined that the automatic moisture content meter is malfunctioning;
a remaining drying time estimating means for estimating the remaining drying time until the drying of the grains stops from each value of the moisture content at the time of occurrence of the failure, a predetermined finishing moisture content set in advance, and a drying curve; and the automatic moisture content meter. When it is determined that there is a failure,
An automatic stop comprising a time measuring means for starting time measurement, and a drying operation stopping means for stopping the drying operation when the measured time reaches a predetermined time before the expiration of the estimated remaining drying time. Device.