JPS5939596Y2 - Circulating grain dryer with moisture measuring device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a circulation-type grain dryer, and more particularly to a circulation-type grain dryer equipped with a grain moisture measuring device for accurately measuring the moisture content of grains.

It is known that when grains are dried to a predetermined degree of dryness, the water content of the grains is electrically measured in order to determine the degree of dryness.

As a measuring device for this purpose, a so-called electric moisture measuring device is used.

However, when measuring the moisture content, or dryness, of grains using this electric moisture measuring device, the moisture gradient of the grains always poses a problem.

This moisture gradient means that the surface and the center of a single grain of grain have different amounts of water content, and the water content increases inward from the surface.

This moisture gradient is significant when grains are dried.

This tendency is particularly strong in the case of paddy.

This is a natural consequence of the moisture in the grain being evaporated from its surface during drying.

This moisture gradient will almost disappear if left after drying in a constant state for a long period of time.

Therefore, in order to accurately measure the moisture content of grains, it is necessary to either leave the grains in a constant state for a long time until the moisture gradient disappears, or measure the moisture content of the grains up to the casing with the moisture gradient, and calibrate this measurement value. That's what I do.

In the former measurement, grains are left to stand until the moisture gradient disappears, which takes time and does not allow rapid measurement.

In the case of the latter measurement, there is a drawback that sufficient calibration cannot be performed unless the moisture gradient is constant.

Furthermore, the moisture gradient decreases with the passage of standing time,
Since the calibration conditions are not constant over time, setting the calibration conditions is difficult and time-consuming.

Circulating grain dryers are usually used to dry grains.

In a circulating grain dryer, feed 1 from the inlet of the drying tube.
The grains are dried to some extent in the drying cylinder and sent out from the outlet of the drying cylinder.

The grains sent out are carried by a conveyor and returned to the entrance of the drying tube, where a circulation process is performed to dry them.

In other words, it is called a circulation type grain dryer because it is a circulation type in which grain is repeatedly fed through a drying tube, circulated, and dried to the required degree.

In this circulating grain dryer, in order to measure the moisture content of grains, the dried grains are left in a certain state for a certain period of time, and then the moisture content is measured electrically, and the moisture gradient in that state is measured. It is best to know this in advance and proofread it.
This makes it possible to know the moisture content of grains relatively accurately.

However, it is actually difficult to measure this grain under certain conditions after the drying process.

This is because the grains returned to the drying cylinder have different stacking positions or densities within the drying cylinder depending on the amount of grain loaded, and the sinking rate is not constant.

Methods and devices for measuring grain moisture in circulating grain dryers have already been proposed.

For example, when measuring the moisture content of grain by directly attaching a moisture detection electrode to the inner wall of a dryer, if the moisture detection electrode is installed in an upward position, the grain may not come into sufficient contact with the electrode surface depending on the amount of lining. In some cases, moisture measurement may become impossible.

However, if the moisture detection electrode is installed at a slightly lower position, the conditions of the grain to be measured for moisture will vary as described above due to the difference in the amount of filling, so reproducible moisture measurement cannot be expected. Moreover, it becomes more easily affected by the heat from the hot air tower, which is undesirable.

Japanese Utility Model Application No. 51-90879 discloses a moisture measuring device for a circulating grain dryer that solves the above problems.

This moisture measuring device has a structure in which a moisture measuring sample tube with a detection electrode attached to the side wall is installed, extending into the drying cylinder from just below the granulating device of the dryer in a case near the discharge device (rotary pulp). A portion of the grain that is circulated to the inlet of the drying tube and returned is passed through this sample tube to measure the moisture content.

The grains in the sample tube are then discharged by the operation of the rotary pulp of the discharge device located near the opening at the lower end of the tube, and the grains in the sample tube slowly sink together with the grains packed inside the drying tube.

In this way, the sample tube is always filled with grains in a constant state and sinks, resulting in a nearly constant moisture condition regardless of the amount of grain added, improving the reproducibility and accuracy of moisture measurement. It is assumed that

However, the above configuration has a problem.

That is, the mounting position is limited due to the arrangement of the grain distributing device that circulates the grains back into the drying cylinder and the rotary pulp mentioned above, and the sample tube becomes long, making the mounting work difficult.

The above-mentioned Japanese Utility Model Publication No. 51-90879 discloses, as another example, a structure in which the lower end of the sample tube is located at a position slightly below the level of the minimum amount of grain to be loaded.

However, this does not indicate any means for positively and smoothly sinking the grains in the sample tube.

Since the diameter of the sample tube is very small compared to the diameter of the drying cylinder, it has the disadvantage that it tends to collapse at its lower end.

This is of course very problematic, especially when the dried grain is paddy.

In addition, inside the drying tube, there are obstacles such as drying towers and reinforcing tension wires scattered below that provide resistance to the sinking of the grains, and the sinking of the tensioned grains is not uniform depending on the location. Since the rotary pulp at the bottom is operated intermittently to increase the drying effect, the grains do not always sink stably in the same pattern, but sink in an unstable state.

In some cases, it becomes stagnant in winter.

Therefore, depending on the mounting position of the sample RW, the grains in the sample tube may be affected by the unstable flow of the grains in the sample tube.

Therefore, the grains in the sample tube are unstable and do not necessarily sink in a uniform pattern.

According to the inventor's experimental analysis, the grains placed around the flat end of the sample tube are housed in the unstable sinking described above, and interfere with the sinking of the grains from the sample tube directly below the bottom end. It was discovered that this prevents the grain from settling in the sample tube.

This invention was made based on this fact,
The main purpose is to maintain stable and almost constant settling of grains in the sample tube.

That is, according to the present invention, in a circulating grain dryer having a grain drying tube and a conveyor that sends grains back from the outlet of the grain drying tube to the inlet, the grain drying tube is placed almost vertically from the inlet of the drying tube slightly above the hot air tower. The moisture measuring device is characterized in that an extending sample tube is provided with an electrode portion of the moisture measuring device attached to the side surface, and the lower end of the sample tube is flared so as to have a larger diameter than the upper end. A circulating grain dryer is provided.

With the above configuration, grains around the lower end of the sample tube are biased outward from the sample tube, preventing interference with the flow of grains flowing out of the sample tube conduit, and preventing grains from flowing out of the sample tube. Subsidence can always be made almost uniform.

The invention will be described in detail below in the form of embodiments with reference to the accompanying drawings.

In the accompanying drawing, 10 is a drying tube, and a plurality of hot air towers 5 are arranged at the bottom of the drying tube 10 so as to be uniformly distributed in its cross-sectional direction.

At the lowest part between the hot air towers 5 and 50, a discharge device 4 for discharging grains is provided.

The partially dried grains are discharged from the grain discharge device 4 to the bottom of the drying cylinder and collected there.

From here, the grains are transported upward by the circulation conveyor 6 and dropped into the drying cylinder from the upper entrance of the drying cylinder 10.

The sample tube 1 extends from the upper entrance of the drying tube 10 to the length directly above the hot-air tower 5, almost along the central axis of the drying tube 10.
is arranged vertically, and the lower end of this sample tube 1 is shaped like a Luer and serves as an outlet with an enlarged diameter.

An electrode section 2 of an electric moisture measuring device is provided on the side wall of the sample tube 1 to measure the moisture content of grains passing through the sample tube 1.

A simple configuration in which the lower end of the sample tube 1 is flared can prevent grains from clumping.

The degree of this flare can be determined experimentally and empirically depending on various conditions such as the arrangement of the drying tube 10, for example, the arrangement of the hot air tower 5 and the sample tube 1, the grain size of the grain, and the amount of grain supplied. be.

Furthermore, the mounting position of the electrode section 2 on the sample tube 1 is preferably as high as possible, since the vehicle is heavy if it is not affected by the heat from the hot air tower.

However, since the grains fall randomly from the upper end of the sample tube 1, a stable packed bed of grains cannot be obtained in this area.

Therefore, the electrode portion 2 is attached at a position near the upper end of the sample tube where a stable grain-filled bed can be obtained, as shown in the figure.

In the attached drawing, the sample tube 1 is placed directly above the hot air tower 5, but the position of the sample tube 1 or the hot air tower 5 may be changed so that it is between the hot air towers 5 and 50. good.

Further, the number of hot air towers 5 is not determined by the arrangement as shown in the attached drawings, and may be simply one, for example.

[Brief explanation of drawings]

The attached drawing is a schematic cross-sectional view showing an embodiment of the present invention. 1... Sample tube, 2... Moisture measuring device,
4...Grain discharge device, 5...Hot air tower,
6... Conveyor, 10... Drying tube.

Claims (6)

[Scope of utility model registration request] (1) A grain drying tube, a conveyor for returning grains from the outlet to the entrance of the grain drying tube, a hot air tower provided below the drying tube, a sample tube extending almost vertically into the drying tube, and a sample tube. and an electric bridge part of the moisture measuring device provided on the side wall of the pipe.
In the moisture measurement equipment, the sample tube extends almost vertically from the upper entrance of the drying tube to a slightly lower part of the hot-air tower, and the lower end of the sample tube sample passage is made into a Lure shape and the diameter is enlarged. A circulating grain dryer having a moisture measuring device. (2) A circulating grain dryer according to claim (1) of the utility model registration claim, wherein the sample tube is provided approximately along the central axis of the drying tube. . (3) The circulating grain dryer according to claim (1), wherein the sample tube is disposed directly above the hot air tower. (4) A circulating grain dryer according to claim (1) of the utility model registration claim, characterized in that a plurality of the hot air towers are provided. (5) A circulating grain dryer as described in order R1 of the utility model registration claim, characterized in that the sample tube is provided directly above the hot air tower. (6) A circulating grain dryer according to item (4) of the utility model registration claim, characterized in that the sample tube is provided between the front flu tower and the hot air tower. .