JPS6136620B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a moisture sensor that can automatically and instantaneously measure the moisture value of grains and powders of rice, wheat, millet, etc.

Conventional well-known moisture sensors (for example, moisture meters for grains) often collect a small amount of the substance to be measured, crush it once, sandwich it between crimped electrode plates, and read only the electrical resistance between them from a pointer. Inconveniently, it is necessary to manually test and measure the temperature and then correct the temperature using an alcohol thermometer, which is time-consuming and the measurement accuracy varies.

Conventionally, a moisture sensor samples and holds a certain amount of powder and granules, and the moisture value of the powder is measured using the dielectric constant of the capacitance between the electrode plates in the moisture sensor. Proposed.

The present inventor further researched and improved this, and adopted a double-tube structure in which the inner tube and the outer tube, which are arranged at equal distances from each other, serve as opposite electrode plates, and the outer surface of the inner tube and the outer tube By covering the inner surfaces of each with an insulating material and insulating the two electrode plates from each other and preventing direct contact between the electrode plates and the powder, the structure is simplified, the measurement accuracy is extremely high, and the sensor performance is improved. When using a moisture sensor for powder and granular materials that can make the most of The purpose is to provide a shutter device that does not pinch powder or granules at the bottom opening, and specifically, an outer cylinder and an inner cylinder that can be energized and are arranged at equal distances from each other are used as opposite electrode plates. , Sampling and holding of powder and granules is introduced between the outer cylinder and the inner cylinder through the upper opening of the outer cylinder for introducing powder and granules, and sampling and holding is performed through the lower opening of the outer cylinder equipped with a shutter device. In the moisture sensor for powder and granule, which can freely discharge the powder and granule and measure the moisture value of a certain amount of sampled and held powder by the dielectric constant of the capacitance between the electrode plates, the above method is used. The inner tube has a built-in printed circuit board that converts the moisture value into voltage and applies a low voltage when the capacitance is small and a high voltage when the capacitance is large. It has a tapered shutter body that closes the lower opening by the bias of a spring and opens it via a solenoid, and when opened and closed, the top of the shutter body engages inside the inner cylinder and prevents the powder from entering the inner cylinder. It is an object of the present invention to provide a moisture sensor for powder and granular material, which is characterized in that it is designed to constantly prevent intrusion.

The details will be explained below based on the illustrated embodiment. The moisture sensor for powder or granular material according to the present invention calculates the moisture value of a certain amount of sampled and held powder by the dielectric constant of the capacitance between the electrodes. The inner cylinder 2 is arranged within the outer cylinder 1 so that the distance between it and the outer cylinder 1 is equal, and the outer cylinder 1 and the inner cylinder 2 are made of stainless steel or other electrically conductive material. The outer cylinder 1 and the inner cylinder 2 are made of a suitable material, and the entire outer cylinder 1 and inner cylinder 2 are made to serve as opposite electrode plates (for example, the outer cylinder 1 is the (-) pole and the inner cylinder 2 is the (+) pole). The moisture value of the powder is measured based on the granularity of capacitance between the outer cylinder 1 and the inner cylinder 2. Incidentally, the outer cylinder 1 and the inner cylinder 2 are formed to have a circular cross section (FIG. 2).

The inner surface 3 of the outer cylinder 1 is covered with an insulating material 4 such as nylon or polyethylene fluoride, and the outer surface 5 of the inner cylinder 2 has an inner surface shape corresponding to the outer surface shape of the inner cylinder 2 and is made of acrylic resin or the like. The outer cylinder 1 and the inner cylinder 2 as both poles are insulated from each other by the cylindrical insulating material 6, so that the two poles and the powder do not come into direct contact with each other. The aim is to improve measurement accuracy and sensor capability.

Further, the outer cylinder 1 has both upper and lower openings 7 and 8, and an appropriate extraction means (not shown) is provided from the upper opening 7.
A shutter device 1 for opening and closing is provided in the lower opening 8 and is capable of introducing a certain amount of powder into the interior 9 through the shutter device 1.
The powder and granular material can be sampled, held, and discharged through the 0. This shutter device 10 is located at a lower opening 8 of an outer cylinder 1, and has a shutter main body 11, which has a substantially tapered shape that tapers toward an upper opening 7 from there, and is constantly urged toward the lower opening 8 by a spring 12. While closing the lower opening 8, the solenoid 13 moves the shutter main body 11 by suction in the opposite biasing direction, specifically, the suction piece 15 connected to the shutter main body 11 via the shaft 14.
is absorbed by the solenoid 13 and the shutter body 11
is moved in the opposite biasing direction to open the lower opening 8. Furthermore, this shutter body 11
The top portion 16 of the shutter body 11 is always engaged with the inside of the inner cylinder 2 when the shutter main body 11 is opened and closed to prevent powder from entering inside the inner cylinder 2.

Also, inside 17 of the inner cylinder 2 is a printed circuit board 1 that forms an electronic circuit for converting the moisture value into voltage.
8 is built-in, and external noise is removed from the outer cylinder 1.
This shielding effect prevents the influence of noise from reaching the printed circuit board 18, thereby making it possible to accurately measure capacitance, and this is one of the features of the present invention. This printed circuit board 18 is configured as a circuit that applies a low voltage to others when the capacitance is small, and a high voltage when the capacitance is large.

A temperature sensor 19 is also incorporated between the outer cylinder 1 and the inner cylinder 2, and can freely measure the temperature of the sampled and held powder in the same way as measuring the moisture value. By incorporating a temperature sensor and directly measuring the temperature of the granular material that is the target of moisture content measurement, temperature correction is facilitated.

As explained above, when using the powder moisture sensor according to the present invention, a printed circuit board that converts the moisture value into voltage is built into the inner cylinder, so that the outer cylinder, which is the (-) pole, The distance from the printed circuit board can be increased, and the effect of external noise can be prevented from reaching the printed circuit board due to the shielding effect of the outer cylinder, making it possible to measure capacitance accurately. Since the lower opening of the outer cylinder is opened and closed via a tapered shutter device that moves up and down using a solenoid and a spring, it is possible to sample, hold and discharge powder without getting it caught in the lower opening. Since the top of the shutter body engages with the inner cylinder at all times to prevent powder particles from entering the inner cylinder, the printed circuit board built into the inner cylinder will not be damaged. Since the tapered shutter body is opened, closed, and moved up and down using a solenoid and a spring, it takes up less space and has a simpler structure than an opening/closing device using a rotating mechanism, which simplifies the overall structure of the moisture sensor. It has many effects, such as being able to make changes.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an example of a powder moisture sensor according to the present invention, and FIG. 2 is an enlarged sectional view taken along the line - in FIG. 1. In the figure, 1... Outer cylinder, 2... Inner cylinder, 3... Inner surface of outer cylinder, 4, 6... Insulating material, 5... Outer surface of inner cylinder,
7, 8... Both upper and lower openings of the outer cylinder, 10... Shutter device, 11... Shutter body, 12... Spring, 13... Solenoid, 16... Top, 1
8...Printed circuit board.

Claims (1)

[Scope of Claims] 1. An outer cylinder and an inner cylinder that can be energized and arranged at equal distances from each other are used as opposite electrode plates, and the powder is introduced into the outer cylinder through the upper opening of the outer cylinder for introducing the powder. The sampled and held powder particles can be freely discharged from the lower opening of the outer cylinder equipped with a shutter device. In a powder moisture sensor that measures the moisture value of a body using the dielectric constant of the capacitance between the electrode plates, the inner cylinder has a sensor that converts the moisture value into voltage and detects when the capacitance is small. There is a built-in printed circuit board that applies a low voltage and a high voltage when the capacitance is large, and the shutter device has a tapered shape in which the lower opening is closed by the bias of a spring and opened via a solenoid. What is claimed is: 1. A moisture sensor for powder and granular material, characterized in that the shutter body has a shutter body, and the top of the shutter body engages inside the inner cylinder when opening and closing to constantly prevent powder and granular material from entering inside the inner cylinder.