JPH0416929Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a device for calibrating the sensitivity of a moisture meter for electrically measuring the moisture contained in powdered materials such as grains.

2. Description of the Related Art In general, as shown in FIG. 4, the electrode section of an electric moisture meter as described above consists of a metal cylindrical body 1 and a cylindrical body 2 disposed in the center, with an annular insulator 3 interposed at their lower ends. An annular space 4 is defined between the cylindrical bodies 1 and 2, the lower end of which is closed by an insulator 3 and the upper end is open. The outer cylindrical body 1 is used as a negative electrode, and the inner cylindrical body 2 is used as a positive electrode, and is connected to an electrical moisture meter (not shown) to generate an electrical quantity that changes depending on the amount of moisture contained in the powder. It is now possible to determine the moisture content of powder and granular materials by measuring

In order to accurately measure the moisture content of powder and granular materials with such a moisture meter, it is necessary to calibrate the variations in sensitivity due to differences in the electrical characteristics of individual moisture meters. is being used.

As shown in FIG. 4, the conventional calibration device includes a disc-shaped lid portion 5 made of an insulating material such as synthetic resin, which is placed on the upper ends of the cylindrical bodies 1 and 2 so as to close the upper end of the moisture meter, and a lid portion. a cylindrical part 6 formed integrally with the cylindrical part 5 and inserted concentrically into the annular space 4 between the cylindrical bodies 1 and 2 of the moisture meter; It has a pair of elastic contact pieces 7 and 8 that are in close contact with the circumferential surfaces of the cylindrical bodies 1 and 2, respectively, and a capacitor 9 provided on the lid portion 5 and electrically connected to the contact pieces 7 and 8, The fixed capacity of this capacitor 9 is used to calibrate the moisture meter.

However, such conventional calibration devices
When attaching it to the moisture meter, the contact pieces 7 and 8 slide against the cylindrical bodies 1 and 2 of the moisture meter, so the electrical contact between them becomes poor due to wear and deformation, resulting in inaccurate calibration of sensitivity. This makes long-term use impossible.Since the contact pieces 7 and 8 have a certain length, they have inductance.For this reason, especially in moisture meters that use high-frequency current, the capacitor 9
There will be a relatively large reactance in series with the contact piece, which will change during long-term use due to deformation of the contact piece and cause errors in calibration, resulting in a relatively long connection between the contact piece 7, 8 and the capacitor 9. Calibration becomes inaccurate due to the reactance of the conductor, and the structure is complicated to fix the connecting conductor.
Furthermore, since the inductance of the contact pieces and connecting wires changes with temperature, there are other problems such as inaccurate calibration.

Problems to be Solved by the Invention Therefore, in order to solve the above-mentioned problems, the present invention is capable of accurately calibrating the sensitivity of a moisture meter over a long period of time, and has a simple and convenient structure. Another object of the present invention is to provide a sensitivity calibration device for a powder moisture meter that is easy to handle.

Means for Solving the Problems According to the present invention, a device for calibrating the sensitivity of a moisture meter that electrically measures the moisture content of a powder by placing a powder in a space between two electrodes is provided. , an elongated cylindrical protrusion is integrally formed on a metal cup-shaped main body, a metal rod is coaxially insulated and supported within this protrusion, and the outer end of the rod is extended outward from the tip of the protrusion. the inner end of the rod protrudes into the inner space of the main body, a capacitor is disposed within the inner space of the main body, and this capacitor is electrically connected to the inner end of the main body and the rod. and a threaded portion is formed on the outer peripheral surface of the protruding portion, and this threaded portion is screwed into a screw hole formed in one of the electrodes, and the outer end of the rod is crimped to the other electrode. It is characterized by

Operation With the above configuration, the protruding part of the main body of the calibration device is passed from its tip through the screw hole of one electrode (outer cylindrical body) of the moisture meter electrode part, and the threaded part of the protruding part is screwed into the screw hole. At the same time, the outer end of the rod is crimped to the other electrode of the center electrode (inner cylindrical body) of the moisture meter electrode part, thereby attaching the calibration device to the predetermined position of the moisture meter and connecting the capacitor in the main body to the moisture meter. good coupling between the two electrodes.

Embodiment FIG. 1 shows a sensitivity calibration device 10 according to the present invention attached to a moisture meter electrode section 11. As shown in FIG. The electrode part 11 is entirely the same as the moisture meter shown in FIG.
and 13, the annular insulator 14, and the annular space 15 correspond to the metal cylinders 1 and 2, the annular insulator 3, and the annular space 4 of the moisture meter shown in FIG. 4, respectively. However, the electrode part 11 has a screw hole 16 formed in the cylindrical body 12 and passing through it laterally,
This screw hole 16 is normally closed by screwing a threaded cap 17 shown in FIG.

The calibration device 10 is shown in more detail in FIG.
It has a metal lid member 19 that electrically shields the inside of the 8. Additionally, the main body 18 integrally defines an elongated cylindrical projection 21 of relatively small diameter extending outwardly from the bottom 20 thereof. The protruding part 21 has a threaded part 22 formed on its outer peripheral surface near the main body part 18, and this threaded part 22 is designed to be screwed into the threaded hole 16 of the cylindrical body 12 of the moisture meter as shown in FIG. It's getting old.

A metal rod 23 is installed coaxially within the protrusion 21 via an insulating sleeve 24.
is a hemispherical outer end 2 that projects outward from the protrusion 21;
5 is integrally formed, and the flat surface of the hemispherical outer end 25 abuts the tip of the protrusion 21 via the annular insulating flange 26 of the insulating sleeve 24. The inner end 27 of the rod 23 extends into the main body 18 and is fixed to the bottom 20 of the main body 18 by a nut 28 via an insulating washer 29.
In this way, the rod 23 is electrically insulated from the main body 18 and the protrusion 21 by the insulating sleeve 24 and the insulating washer 29, and is attached to the protrusion 21 so that it cannot be detached from the protrusion 21. A capacitor 30 is arranged in the internal space of the main body 18 , one end of the capacitor 30 is soldered to the inner surface of the main body 18 , and the other end of the capacitor 30 is a lug member 31 held between a nut 28 and an insulating washer 29 . It is soldered on.

When calibrating the sensitivity of the moisture meter, the annular space 15 of the electrode section 11 is emptied and the cap 17 is removed from the screw hole 16 of the cylindrical body 12. Next, the protrusion 21 of the main body 18 of the calibration device 10 is inserted into the cylindrical body 12.
The rod 23 is inserted into the screw hole 16 from the outside, and the screw portion 22 of the protrusion 21 is screwed into the screw hole 16, and the outer end 25 of the rod 23 is crimped onto the outer peripheral surface of the cylindrical body 13 between the electrodes 11. In this way, the projection 21 is electrically connected to the cylinder 12 at the threaded part 22 and the rod 23 is electrically connected to the cylinder 13 at its outer end 25. Preferably, the outer end 25 of the rod 23 is plated with gold to make the electrical contact with the cylindrical body 13 even better.

Effects of the invention With the configuration described above, the present invention can reliably obtain good electrical contact between the moisture meter and the calibration device, and since the contact portion of the calibration device with the moisture meter does not slide, the contact portion To avoid wear and deformation or poor contact, and therefore to have an extremely long device life, and to make the device structure as small, compact, and robust as possible, and to perform sensitivity calibration with extremely high accuracy. This has advantages such as ease of handling and operation of the device.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the electrode section of an electric powder moisture meter equipped with a sensitivity calibration device according to the present invention.
2 is a sectional view of the sensitivity calibration device shown in FIG. 1, FIG. 3 is a perspective view of a threaded cap that closes the screw hole 16 of FIG. 1 in a normal state, and FIG. 4 is a sectional view of the sensitivity calibration device shown in FIG. FIG. 2 is a longitudinal cross-sectional view of a moisture meter electrode section to which a conventional sensitivity calibration device is attached. 10... Sensitivity calibration device, 11... Electrode section, 1
2, 13... Cylindrical body, 15... Annular space, 16...
...Threaded hole, 17... Threaded cap, 18... Main body, 19... Lid member, 21... Projection, 22...
...Threaded portion, 23... Rod body, 24... Insulating sleeve, 25... Outer end, 27... Inner end, 30...
capacitor.

Claims (1)

[Scope of utility model registration request] In a device for calibrating the sensitivity of a moisture meter that electrically measures the moisture content of powder fluid by placing powder fluid in the space between two electrodes, an elongated cylindrical protrusion is integrated into a metal cup-shaped main body. A metal rod is coaxially insulated and supported within the protrusion, and the outer end of the rod is made to protrude outward from the tip of the protrusion, and the inner end of the rod is connected to the main body. a capacitor is arranged in the internal space of the main body, the capacitor is electrically connected to the inner end of the main body and the rod, and the outer circumferential surface of the protrusion A powder particle characterized in that a threaded portion is formed in the rod, the threaded portion is screwed into a screw hole formed in one of the electrodes, and the outer end of the rod is crimped to the other electrode. Sensitivity calibration device for body moisture meter.