JPH04290926A - Liquid quantity sensing device - Google Patents

Abstract

PURPOSE:To visually detect the quantity of liquid in a tank, etc., from a remote place by changing the position of a magnet in compliance with the liquid quantity, and sensing the impedance corresponding to the changing magnet position. CONSTITUTION:When a float 12 moves up and down in compliance with the liquid level in a tank T, a band 13 rotates, and a scale plate 21 rotates interlockingly to indicate the residual liquid quantity in the tank T. A magnet M is mounted on a rotary disc 22, and when this disc 21 rotates, the angular position of the magnet M varies. The angular position is sensed by reed switches S1-S5, when only the one which has made sensing will be turned on. Now the load resistance of battery changes, and the amperage in accordance with load resistance is indicated by an ammeter. This current value is led to a certain display position, and the residual quantity of the liquid L is displayed following the change in the sensed amperage. Between those reed switches, there is an overlapped sensing zone where both switches are turned on simultaneously. In this case, however, one of them is ignored because of difference between the impedances, and no uncontinuous region is produced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid amount detecting device that allows the amount of liquid such as petroleum contained in a tank or the like to be visually checked from a position away from the tank.

0002

[Prior art] The amount of liquid such as petroleum in a tank etc.
As a device that can be visually checked from a distance from the tank, a device that combines a float, a plurality of relays, and a meter such as an ammeter is known. That is, the position of the float changes depending on the amount of liquid, the relay that operates differs depending on the position of the float, and the swing amplitude of the meter varies depending on the relay that operates.

0003

[Problems to be Solved by the Invention] The above-mentioned conventional device has the problem that the relays that make up the device are expensive, and the use of a large number of relays increases the price of the entire device, and also increases the size of the device. There is a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid amount detection device that allows the amount of liquid contained in a container such as a tank to be visually checked from a position away from the tank, and that can be constructed at a low cost. be.

[0005]

[Means for Solving the Problems] The present invention provides an impedance circuit in which a magnet whose position changes according to the amount of liquid is provided, an impedance circuit whose impedance changes according to the position of the magnet, and an impedance circuit which detects the impedance of this impedance circuit. The impedance circuit is a magnetic sensor installed at a predetermined angle or a predetermined distance, and one end of which is connected to one end of the impedance circuit. a first resistor connected between the other end of the first magnetic sensor and the other end of the impedance circuit; , a resistor connected between the other end of the nth magnetic sensor and the other end of the n-1th magnetic sensor, and a magnet is located approximately in the middle area between two adjacent magnetic sensors. When positioned, the two adjacent magnetic sensors detect the magnet simultaneously.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

The bearing plate 10 is screwed into the inlet of a tank T containing heavy oil, gasoline, etc., and guide rods 11a and 11b are fixed to the lower surface of the bearing plate 10 so as to hang down. ing. The float 12 is made of foamed synthetic resin or the like, and has two round holes and one square hole, and the guide rod 11a is inserted into the round hole.
, 11b are loosely fitted, and a band plate 13 is loosely fitted into the rectangular through hole. The strip 13 is twisted approximately 180 degrees. The upper end of the strip plate 13 is connected to the lower end of a rotating shaft 20 that passes through the center of the bearing board 10, and the lowermost end of the strip plate 13 is supported by a bearing 14, which is connected to the guide rod 1.
It is installed on a bar 15 fixed to the lower part of 1a and 11b.

The upper part of the rotating shaft 20 is fixed to the center of the lower part of the scale plate 21, and a permanent magnet M is fixed to the upper surface of the scale plate 21. Incidentally, the scale plate 21 has a substantially disk shape, and a tapered portion is provided at the upper part of the circumferential surface, and a scale is attached to the tapered portion. The transparent cover 22 is a waterproof cover that covers the scale plate 21, and its lower part engages with the bearing plate 10, and the wiring board 30 is fixed to its upper part.

FIG. 2 shows the bearing plate 10 in the above embodiment.
FIG. 3 is an exploded perspective view showing a portion located above the holder.

The transparent cover 22 is provided with a pointer 22a, and the wiring board 30 is provided with a battery B such as 1.5V, an ammeter A, and reed switches S1, S1, S2, S3, S4,
S5 and resistors R1, R2, R3, R4, and R5 are provided. The reed switches S1 to S5 are arranged directly above the locus of the permanent magnet M, and are arranged radially from the center of the rotating shaft 20 at predetermined angle intervals. In addition,
In order to know the amount of liquid at a location away from the wiring board 30, the ammeter A may be installed at a distance from the wiring board 30. In this case, in order to effectively utilize the space on the wiring board 30, it is preferable that the battery B is also separated from the wiring board 30.

[0011] Also, for example, reed switches S1 and S2
Focusing on this, reed switches S1 and S2 are set to detect magnet M at the same time when permanent magnet M is located approximately in the middle area between the two, and in this way, reed switches S1 and S2 simultaneously detect magnet M. The area in which this is detected is called the "overlapping detection area." That is, for example, when the magnet M is placed directly below the reed switch S1, only the reed switch S1 detects the magnet M, and when the magnet gradually rotates toward the reed switch S2, the reed switches S1 and S2 There is a region (overlapping detection region) in which both are detected at the same time, and only the reed switch S2 comes to detect the magnet M when passing through the overlapping detection region.

The same applies to the reed switches S2 to S5, that is, when the magnet M is located approximately in the middle area between two adjacent reed switches, the two adjacent reed switches detect the magnet M at the same time. There is a duplicate detection area. Note that another magnetic sensor that detects magnetism may be provided instead of the reed switch.

FIG. 3 is a diagram showing an equivalent circuit of the above embodiment.

The above embodiment includes a magnet M whose position changes depending on the amount of liquid, an impedance circuit 31 whose impedance changes according to the position of the magnet M, and impedance detection means for detecting the impedance of this impedance circuit 31. 32. The impedance circuit 31 includes n (n is a positive integer of 2 or more) magnetic sensors installed at predetermined angles or predetermined distances, one end of which is connected to one end of the impedance circuit 31; The other end of the magnetic sensor and impedance circuit 3
1 and the other end of the nth magnetic sensor and the other end of the n-1th magnetic sensor. When the magnet M of the circuit 31 is located approximately in the middle area between two adjacent magnetic sensors, the two adjacent magnetic sensors simultaneously detect the magnet M.

Specifically, one end of the reed switches S1 to S5 is connected to a terminal 31a of the impedance circuit 31, and the other end of the reed switches S1 to S5 is connected to a resistor R.
The resistor R1 is connected between the other end of the reed switch S1 and one end 31b of the impedance circuit 31. The other end of the resistor R2 is connected to the connection point between the reed switch S1 and the resistor R1, and the resistor R2 is connected to the connection point between the reed switch S1 and the resistor R1.
3 is connected to the connection point between reed switch S2 and resistor R2, the other end of resistor R4 is connected to the connection point between reed switch S3 and resistor R3, and the other end of resistor R5 is connected to the connection point between reed switch S2 and resistor R2. It is connected to the connection point between S4 and resistor R4.

Further, the impedance detection circuit 32 has terminals 32a and 32b, and is constituted by a series circuit of a power source B and an ammeter A.

Next, the operation of the above embodiment will be explained.

When the amount of liquid L in the tank T changes, the height of the float 12 changes according to the height of the liquid level, so the strip plate 13 rotates by a predetermined angle according to the height. The rotating shaft 20 and the scale plate 21 rotate in conjunction with the band plate 13. The remaining amount of the liquid L in the tank T is displayed on the scale plate 21, and the remaining amount of the liquid L in the tank T can be visually confirmed by reading the scale corresponding to the pointer 22a provided on the transparent cover 22.

By the way, when the scale plate 21 rotates due to the vertical movement of the float 12, the angular position of the magnet M changes. The position of this magnet M is set by the reed switches S1 to S.
5 is detected, only the detected reed switch is turned on, and the load resistance of battery B changes as reed switches S1 to S5 turn on and off, and ammeter A measures the current value according to this change in load resistance. indicate. Note that in FIG. 2, only the reed switch S2 is turned on because FIG. 2 shows an example in which the magnet M is present at a position where only the reed switch S2 detects the magnet M.

[0020] Then, reed switches S1, S2, S3
, S4, and S5 detect the magnet M, respectively, as D1, D2, D3, D4, and D5, there is an overlapping detection area where both the reed switches S1 and S2 detect the magnet M. Similarly, for reed switches S2 to S5, overlapping detection regions exist between mutually adjacent reed switches. Note that the detection region D0 is a region in which neither reed switch detects the magnet M, and indicates that the remaining amount of the liquid L is zero or close to zero.

Specifically, when the liquid level of the liquid L is located near the upper end of the tank T, the reed switch S1 is turned on, and only the resistor R1 becomes a load on the battery B, and the maximum current (ratio 5 current) flows. Then, as the liquid level gradually decreases, the reed switches S2, S3, S4, S5
When the remaining amount of liquid L becomes zero, all reed switches are turned off and the load resistance of battery B becomes maximum. Therefore, as the liquid level decreases, the load resistance value of battery B gradually increases and the current value also decreases. These states are shown in FIG.

By the way, for example, if the magnet M is located in the overlap detection area where reed switches S1 and S2 both detect, reed switches S1 and S2 are turned on at the same time, but in this case, when viewed from battery B, the reed switch S2
Even if the reed switch S2 is turned on, the impedance of the reed switch S1 is lower than that of the resistor R2 connected in series with the reed switch S2, so the resistor R2 is ignored (the ON state of the reed switch S2 is ignored), and only the resistor R1 is connected to the battery. This becomes a load on B. In other words, when magnet M is located between reed switches S1 and S2, ammeter A
The display is the same as when only 1 is turned on. That is, when the reed switch S1 detects the magnet M and then the reed switch S2 detects the magnet M, a discontinuous region in which neither reed switch detects the magnet M occurs in the boundary region; Even if two reed switches detect the magnet M at the same time, no abnormality will occur in the detection results. Further, since the amount of liquid contained in a container such as the tank T can be reliably visually checked from a position away from the tank, and no relay is used, the liquid amount detection device can be constructed at a low cost.

FIG. 5 is a diagram showing an equivalent circuit when an impedance detection circuit 33 is used instead of the impedance detection circuit 32 used in the equivalent circuit shown in FIG. It is a figure which shows the relationship between the liquid volume and the ratio of a voltage value in the example shown.

The impedance detection circuit 33 has terminals 33a and 33b, and is composed of a series circuit of a power source B and a resistor R, and a voltmeter V connected in parallel with this series circuit.

In the above embodiment, as the liquid L decreases, the reed switches S1, S2, S3,
Turn on S4 and S5 in that order (that is, R1, R1+R2
, R1+R2+R3, R1+R2+R3+R4, R1+
The resistance value changes in the order of R2+R3+R4+R5), but the reed switch may be arranged in the opposite direction (that is, R1+R2+R3+R4+R5).
5, R1+R2+R3+R4, R1+R2+R3, R1
The resistance value changes in the order of +R2 and R1). By doing this, as the liquid L increases, the reed switch S1
, S2, S3, S4, and S5 are turned on in this order, and in this case, the ammeter A may display such that the remaining amount of liquid L increases as the detected current value decreases. To obtain a similar result, the twisting direction of the strip 13 may be reversed from that of the above embodiment. When using the voltmeter V, the voltmeter V may display such that the remaining amount of the liquid L increases as the detected voltage value decreases.

FIG. 7 is an explanatory diagram showing another embodiment of the present invention, in which FIG. 7 (1) is a front view thereof, and FIG. 7 (2) is a longitudinal sectional side view thereof.

In the embodiment shown in FIGS. 1 to 6, the scale plate 21 rotates according to the remaining amount of the liquid L, and the magnet M rotates in accordance with this rotation. In the embodiment shown in 7, as the remaining amount of the liquid L increases or decreases, the magnet M1
moves up and down, and reed switches S11 to S15 and resistors R11 to R15 are provided at positions corresponding to the up and down movement of the magnet M1. Reed switches S11 to S15 and resistor R
The connection status of 11 to R15, battery B, and ammeter A is as follows:
This is the same state as shown in FIG.

Note that the wiring board 31 of the electric circuit connecting the reed switches S11 to S15, the resistors R11 to R15, the battery B, and the ammeter A is fixed to a transparent cover 22a, and this cover 22a is attached to the upper lid of the tank T. Fixed. In addition to vertical movement, the magnet M may also linearly reciprocate, such as left and right movement.

In the above embodiment, five reed switches and five resistors are used, but a plurality of reed switches other than five may be used.

Note that in the above embodiment shown in FIG.
3 is twisted almost 180 degrees, but this twist angle is
It is determined as appropriate depending on the number of reed switches and resistors provided on the wiring board 30 and their arrangement angle. In addition, the number of reed switches and resistors and their arrangement angles are determined depending on the actual rotation angle of the rotating shaft 20 that interlocks with the strip plate 13 (actual height when the float 12 moves up and down). may be determined.

Furthermore, as a means for changing the position of the permanent magnet M in accordance with the liquid amount, means other than the means shown in FIG. 1 may be used.

Furthermore, a switch may be provided between the terminal 32b of the impedance detection means 32 and the ammeter A, or a switch may be provided between the terminal 33b of the impedance detection means 33 and the power source B. good. In this way, the switch will be pressed only when you want to know the amount of liquid, and the consumption of the power source B will be greatly reduced, and the life of the power source B will be extended. Note that the connection position of the switch is not limited to the above position, and may be any other position as long as it is connected in series with the power source B.

[0033]

According to the present invention, the amount of liquid contained in a container such as a tank can be reliably visually confirmed from a position away from the tank, and the system can be constructed at a low cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view of essential parts of the above embodiment.

FIG. 3 is a diagram showing an equivalent circuit of the above embodiment.

FIG. 4 is a diagram showing the relationship between the liquid amount and the current value ratio in the above embodiment.

5 is a diagram showing an equivalent circuit when an impedance detection circuit 33 is used instead of the impedance detection circuit 32 used in the equivalent circuit shown in FIG. 3. FIG.

6 is a diagram showing the relationship between the liquid amount and the voltage value ratio in the embodiment shown in FIG. 5. FIG.

FIG. 7 is a diagram showing another embodiment of the present invention, and FIG.
) is its front view, and figure (2) is its longitudinal side view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10... Bearing board, 11a, 11b... Guide rod, 12... Float, 13... Band plate, 20... Rotating shaft, 21... Scale board, 22... Transparent cover, 30... Wiring board, 31... Impedance circuit, 32, 33... Impedance detection circuit, S1 to S5, S
11~S15...Reed switch, R1~R5, R11~
R15, R...Resistance, A...Ammeter, V...Voltmeter, M...Permanent magnet.

Claims (2)

[Claims] [Claim 1] A magnet whose position changes according to the amount of liquid;
It includes an impedance circuit whose impedance changes depending on the position of the magnet, and an impedance detection means for detecting the impedance of the impedance circuit,
n (n is a positive integer of 2 or more) magnetic sensors installed at predetermined angles or predetermined distances, one end of which is connected to one end of the impedance circuit; the first of the magnetic sensors; a first resistor connected between the other end of the sensor and the other end of the impedance circuit; the other end of the nth magnetic sensor; and the other end of the n-1th magnetic sensor; the impedance circuit has a resistor connected between; and when the magnet is located approximately in an intermediate region between the two adjacent magnetic sensors, the two adjacent magnetic sensors connect to the magnet. A liquid amount detection device characterized by simultaneously detecting. 2. In claim 1, the impedance detection circuit comprises a series circuit of a power source and an ammeter, or a series circuit of a power source and a resistor, and a voltage sensor connected in parallel with the series circuit. A liquid amount detection device comprising: a meter;