JPS5927218A - Method for detecting rotation of flowmeter - Google Patents

Abstract

PURPOSE:To detect the rotation with high resolution without using a magnetic sensitivity element, by providing a rotatable conducting shaft and a conductive fixed shaft, to which wings that are overlapped with blades and made to form capacitors with a gap being provided from the blades are attached. CONSTITUTION:The central part of a magnet 5 is fixed to the lower end part of a conducting shaft 8 through an insulating member 7. Said conducting shaft 8 is rotatably supported by the upper and lower plates of an insulating case 9. A conductive fixed shaft 14 is electrically connected to an external electric circuit. A plurality of conducting wings 15, which can be overlapped with rotary blades 13, are horizontally attached and fixed to the fixed shaft 14, with a gap being provided from the rotary blades 13. Capacitors are formed by the wings 15 and the rotary blades 13. The rotation of the measuring part of a flowmeter is converted into the variation of the electric capacities caused by the overlap of the rotary blades and the conducting wings and the result is detected. Therefore the rotation can be detected with high resolution without using a magnetic sensitivity element.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flowmeter rotation detection method that can electrically convert measured values of a flowmeter with high resolution and low power consumption.

Conventionally, the method of electrically detecting the rotation of a flowmeter is as follows:
For example, as shown in FIG. 1, the rotation generated in the flow metering section λ built into the housing according to the measured value is transmitted to a magnet ≠ attached coaxially with the rotating shaft 3, and the rotation of the magnet 14 causes This is done by synchronously rotating another magnet J disposed close to and facing the magnet ≠ outside the housing, which is detected by the magnetic sensing element B and converted into a predetermined electrical signal. However, with this method, it is not possible to increase the number of magnetic poles of the magnet j due to the operation of the magnetic sensing element B, so it is not possible to electrically convert the measured value with high resolution, and the Hall element and magnetoresistive effect Magnetic sensing elements such as elements B were economically disadvantageous due to their large current consumption.

The present invention provides a rotation detection method for a flowmeter that solves the problems of the conventional art, and embodiments of the present invention will be described below with reference to the drawings.

Figure 2 shows an example of the apparatus used in the method of the present invention.
The point that the rotation of the magnet ≠ inside the housing is transmitted to other magnets is the same as in the conventional case, but the driven magnet 1 is fixed at its center to the lower end of the conductive shaft g via an insulating material 7. The conductive shaft is rotatably supported by the bottom panel of the insulating case 7, and a conductive plate 10 is provided inside the upper plate of the insulating case, which is always in contact with the shaft. It is electrically connected to an external electronic circuit (for example, Fig. 1) via a plate 10. // is an outer case attached to the upper side of the housing to support and fix the insulating case 7, and is designed to provide electrostatic shielding from the outside.

Seven or more thin metal plates/2 are placed horizontally around the conductive shaft and middle part of the insulating case.
The metal plates/2 are plural as shown in Fig.
The blade/3 is integrally formed of the same material, and the blade/3 is integrally formed with the same material.
is adapted to rotate together with the conductive axis g.

/Hiro is a conductive fixed shaft fixed to one side inside the insulating case, and is electrically connected to the external electronic circuit.
On the fixed shaft /≠, seven conductive blades /j or a plurality of conductive blades /j which can be superimposed on the rotary blade /3 with a slight gap due to the rotation of the rotary blade /3 are horizontally attached and fixed, and the blades /j and rotating blade /3 form a capacitor.

Thus, the rotation obtained by the measuring part λ is transmitted to the driven magnet t via the magnet ≠, and rotates the blade /3 together with the conductive shaft g. Depending on the rotation angle of the rotary blade /3, the area forming the capacitor by overlapping with the conductive blade /j changes, so the capacitance changes. Therefore, by converting this change in capacitance into an electrical measurement value using an external electronic circuit and performing arithmetic processing, it is possible to accurately read the rotation in the metering section of the flowmeter.

Figure 5 shows an example of this external electronic circuit, in which the capacitance change described above is converted into a frequency change for calculation, /B is an oscillation circuit, /7 is a reference frequency oscillation circuit, /♂ is a phase comparator, / is a filter 1, and 20 is an arithmetic circuit.

Fig. 3 shows the rotation obtained by the measuring section 2 by the opposing magnets 14. This shows another embodiment in which the electric current is transmitted directly to the conductive shaft ♂ without using the conductive shaft ♂. An arm 22 branches out from the head of the shaft 3 and is configured to be able to come into contact with a horizontal lever 23 attached to the lower end of the conductive shaft/j. is transmitted to the conductive axis /j through the conductive axis /j. A part of the above-mentioned external electronic circuit is printed on the upper plate 2≠ of the insulating case, and the conductive plate 1 in contact with the conductive shaft g
0 and the fixed shaft /4', and detect the change in capacitance due to the change in the overlapping area of the rotating blade /3 and the conductive blade /4', which form a capacitor in the same way as described above. .

Note that seven metal plates /2 with rotating blades /3 and seven conductive blades /j each may be used, but in order to amplify the capacitance of the capacitor, it is preferable to provide multiple stages as shown in the figure. Since it is necessary to configure the blade so that it overlaps or separates from the rotating blade/3 as the rotating blade/3 rotates, its area is of course determined according to the number (and therefore the width) of the rotating blade/3. It is.

As described above, the present invention converts the rotation of the metering part of the flowmeter into a change in capacitance caused by the superposition of the rotating blade and the conductive blade, and therefore detects it with high resolution. It has various advantages, such as less current consumption because no elements are used.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an example of a conventional method of electrically detecting the rotation of a flowmeter, Fig. 2 is an explanatory diagram showing an example of a device used in the method of the present invention, and Fig. 3 is an explanatory diagram of the main parts thereof. An explanatory plan view, Figure 11 is an explanatory diagram of another device used in the method of the present invention, Figure 5
The figure is an explanatory diagram showing an example of an applied circuit for detecting rotation according to the method of the present invention. Code explanation/...Case!・・Measuring part 3・・Rotating axis
≠, 5... Magnet B... Magnetic sensing element
7.Insulating material and conductive shaft Ta..Insulating case 10..Conducting plate //..Outer case/2..
Metal plate /3...Blade/4'...Fixed shaft
/j... Conductive blade / B... Oscillation circuit /7... Reference frequency oscillation circuit/ and... Phase comparator /9... Filter 20...
Arithmetic circuit 2/...Seal 22...Arm
23...Horizontal lever 2≠...Top plate.

Claims (4)

[Claims] (1) Equipped with a rotatable conductive shaft equipped with a plurality of blades in an insulating case and a conductive fixed shaft equipped with blades that overlap with the blades with a slight gap to form a capacitor. Rotation detection of a flow meter, characterized in that the rotation of the measuring part of the meter is transmitted to the conductive shaft, and the change in electric capacity due to the overlap between the rotary blade and the fixed blade is converted into an electrical measurement value and arithmetic processing is performed. Method. (2) The method for detecting rotation of a flowmeter according to claim 1, wherein a plurality of rotating blades and fixed blades forming the capacitor are provided above and below and configured to be superimposed. (3) The rotation of the flow rate metering section is transmitted to the conductive shaft by attaching a magnet to the upper end of the rotating shaft and disposing another magnet oppositely to the lower end of the conductive shaft. 2. The method for detecting rotation of a flowmeter according to item 2. (4) Transmission of rotation of the flow rate metering section to the conductive shaft is accomplished by extending an arm from the head of the rotating shaft of the metering section, attaching a conductive shaft Nlever, and making contact between the arm and the lever. 2. The method for detecting rotation of a flowmeter according to item 1 or 2.