JP3172230B2 - Liquid level detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level detecting device for detecting the liquid level of a liquid such as kerosene in an oil tank or water in a water container.

[0002]

2. Description of the Related Art This type of liquid level detecting device is disclosed in
As described in Japanese Unexamined Patent Publication No. 2-153135, a float with a magnet, a reed switch opened and closed by a magnet of the float, which is used for detecting the liquid level of an oil tank of an oil combustor, A liquid level determining device for determining a liquid level in accordance with an electric signal.

[0003] The reed switch is housed in a bottomed cylindrical guide body on which the float is loosely supported. Then, a lead wire connected to the reed switch is led out through an opening above the guide body, and is connected to the liquid level determination device.

[0004]

By the way, in order to easily perform operations such as inspection and replacement of the reed switch, a connector has been interposed in the lead wire. However, in this case, the electric signal supplied to the liquid level determination device is the same when the reed switch is off and when the connector is not sufficiently connected or the connector is disconnected, so that the reliability is improved. Had the disadvantage that the

Further, when a plurality of reed switches which are opened and closed by a magnet of the float are provided and the liquid level is detected in multiple stages by the electric signals of these reed switches, the number of lead wires increases by that much, and the number of leads increases. Since the number of terminals also increased, there was a concern that the connection of the connectors would be insufficient.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned facts. In the present invention, an electric signal from a reed switch is supplied to a liquid level discriminating device via a connector to detect a liquid level. The purpose is to improve the performance.

[0007]

According to the present invention, there is provided a float with a magnet, a reed switch opened and closed by the magnet of the float, and a resistor connected in parallel to the reed switch. the parallel circuit is connected to a connector provided with a liquid level judgment unit which receives the electrical signal generated at the output side of the connector, and, prior to
The float between the reed switch, resistor and connector
Mounted on a circuit board housed in a guide body fitted and supported
And is a configuration that.

Further, according to the present invention, there is provided a float with a magnet, a plurality of reed switches opened and closed by the magnet of the float, and a resistor connected in series to at least one of the plurality of reed switches. And a liquid level discrimination device that connects the reed switch or a series circuit of the reed switch and the resistor in parallel, connects the parallel circuit to a connector, and receives an electric signal generated at an output side of the connector as an input. And said Lee
The float is loosely supported between the switch, resistor and connector
Mounted on a circuit board housed in a guided body .

[0009]

In the liquid level detecting device according to the first aspect, the lead level
The float is loosely supported between the switch, the resistor and the connector.
Mounted on the circuit board housed in the guide body
When the reed switch is off, a current flows through the resistor and a predetermined electric signal is generated at the output side of the connector when the connector is sufficiently connected. On the other hand, when the connection of the connector is insufficient, regardless of whether the reed switch is on or off, no current flows to the input side of the connector, and a different electric signal is generated at the output side of the connector. For this reason, it is possible to determine whether the connection state of the connector is good or not, and if necessary, check or replace the reed switch.
Such operations as replacement can be easily performed, and the reliability of the liquid level detecting device can be improved.

According to a second aspect of the present invention, there is provided a liquid level detecting apparatus for detecting a liquid level in multiple stages using a plurality of reed switches in addition to the function of the first aspect. Since the series circuit of the resistor and the resistor is connected in parallel, multi-step electrical signals are output to the connector according to the on / off state of the reed switch without increasing the number of lead wires (two) connected to the connector. Can be generated, the connection of the connector is easy and reliable, and the reliability is improved.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 shows a liquid level detecting device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an oil tank having an insertion port 2 on an upper surface, and kerosene 3 is stored. Reference numeral 4 denotes a bottomed cylindrical guide body, on which a float 6 having a magnet 5 is loosely supported. The guide body 4 houses a circuit board 9 on which a reed switch 7 opened and closed by a magnet 5 of a float 6 and a resistor 8 are mounted. The circuit board 9 has an upper portion protruding above the upper opening 10 of the guide body 4.
A has a female connector 11A attached thereto. Reference numeral 12 denotes a lid 12 that covers the protruding portion of the circuit board 9, and has an opening 13 that exposes the upper end of the female connector 11A to the outside.
11B is a male connector detachable from the female connector 11A, and the male connector 11B has two lead wires 1B.
It is connected to the liquid level discriminating device 16 via 4 and 15.

FIG. 2 shows an electric circuit of the above-described liquid level detecting device. A reed switch 7 and a resistor 8 are connected in parallel on a circuit board 9 and this parallel circuit is connected to the female connector 1.
1A. On the other hand, of the two lead wires 14 and 15 connected to the male connector 11B, one lead wire 14 is connected to a DC power supply terminal 17 in a liquid level determination device 16 via a resistor 18 and the other lead wire. Reference numeral 15 is connected to a ground terminal 19. 20 is a male connector 11B
Is a microcomputer that reads the voltage signal on the output side of the microcomputer and determines the liquid level, and has an A / D converter 21 built-in.

The oil level (liquid level) L of the oil tank 1 is LH in FIG.
When it is higher than this, the reed switch 7 is open (off). At this time, the power supply voltage is divided by the resistor 18 and the resistor 8, and the voltage on the output side of the male connector 11B becomes, for example, 2.5 V as shown in Table 1. At this time, the microcomputer 20 reads this voltage via the A / D converter 21, and the oil level L of the oil tank 1 is in the state of I (L> LH).
Is determined. The oil level L is LH or less (LL
Above), the reed switch 7 is closed (ON), and the voltage on the output side of the male connector 11B becomes 0 V. Therefore, the microcomputer 20 indicates that the oil level L is in the state II (LH ≧ L ≧ LL). Is determined. On the other hand, if the connection of the connectors 11A and 11B is insufficient irrespective of the height of the oil level L, no current flows through the reed switch 7 and the resistor 8, so that the voltage on the output side of the male connector 11B becomes 5V. The microcomputer 20 determines the state III (connector disconnection).

[0015]

[Table 1]

According to this embodiment, the connectors 11A, 1
The output voltage (input voltage of the microcomputer 20) of the male connector 11B differs between the case where the connection state of the connector 1B is good and the reed switch 7 is off and the case where the connection of the connectors 11A and 11B is insufficient. Therefore, the microcomputer 20 can clearly discriminate these, and when the connection of the connectors 11A and 11B is insufficient, for example, it is possible to activate a display (not shown) to notify the abnormality. .

Incidentally, as shown in FIG.
4, a resistor 18 may be connected between the male connector 11B and the ground terminal 19 as shown in FIG.

FIGS. 5 and 6 show another embodiment of the present invention. In this embodiment, what is different from those shown in FIGS. 1 and 2 is that two reed switches 23 and 24 are provided on a circuit board 9 and a resistor 2 connected in series to each of them.
5 and 26 are provided, and a circuit in which these series circuits and the resistor 8 are connected in parallel is connected to the female connector 11A. Also, two reed switches 23, 24
Are set so that their height positions partially overlap.

In this embodiment, as shown in Table 2, two reed switches 23,
24 turns on and off, and the combination of the on and off changes the voltage on the output side of the male connector 11B.
The microcomputer 20 can determine the height of the oil level in four stages. Moreover, only two lead wires 14 and 15 are required, and the connectors 11A and 11B can be easily and reliably connected. Of course, even when the reed switches 23 and 24 are both off, the resistors 18 and 8
Thus, the power supply voltage is divided so that a predetermined voltage is generated at the output side of the male connector 11B, so that the state of disconnection of the connector can be clearly determined.

[0020]

[Table 2]

In the above-described embodiment, the microcomputer 20 incorporating the A / D converter 21 is used to detect the liquid level and the disconnection of the connector. However, as shown in FIG.
A plurality of comparators 27 to 29 may be provided in place of the A / D converter, and the output of the comparators 27 to 29 may be used to detect the liquid level and the disconnection of the connector.

[0022]

According to the present invention, the liquid level detecting device according to the first aspect of the present invention is connected to the output side of the connector when the reed switch is off and when the connection of the connector is insufficient. different electrical signals generated, as possible out to determine abnormalities such as loss connector. connector
If the connection is abnormal, correct and secure the connection.
If the circuit board is taken out according to the
Checking and replacing the reed switch can be easily performed.
I can do it. In the liquid level detecting device according to the second aspect , the above-described effect is obtained.
When performing multi-stage liquid level detection in addition to the fruit to be able to generate different electrical signals multistep the output side of the connector without increasing the number of leads, simple connector connection, and to ensure Thus, the function and reliability of the liquid level detecting device can be improved, for example, the liquid level can be detected in multiple stages .

[Brief description of the drawings]

FIG. 1 is a schematic structural explanatory view of a liquid level detecting device according to an embodiment of the present invention.

FIG. 2 is an electric circuit diagram of the liquid level detection device.

FIG. 3 is an electric circuit diagram showing another example of the liquid level detection device.

FIG. 4 is an electric circuit diagram showing still another example of the liquid level detecting device.

FIG. 5 is a schematic structural explanatory view of a liquid level detecting device showing another embodiment of the present invention.

FIG. 6 is an electric circuit diagram of the liquid level detecting device.

FIG. 7 is an electric circuit diagram showing another example of the liquid level determination device.

[Explanation of symbols]

 5 Magnet 6 Float 7, 23, 24 Reed switch 8, 25, 26 Resistance 11A, 11B Connector 16 Liquid level discrimination device

Continued on the front page (72) Inventor Takeshi Osawa 2--18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Katsumi Morito 2--18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. In-house (56) References JP-A 56-135131 (JP, U) JP-A 56-70521 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01F 23/62 G01F 23/30

Claims (2)

(57) [Claims] 1. A float having a magnet, a reed switch opened and closed by a magnet of the float, and a resistor connected in parallel to the reed switch, wherein a parallel circuit of the reed switch and the resistor is connected to a connector. A liquid level discrimination device that receives an electric signal generated at an output side of the connector as an input, and further includes a reed switch, a resistor,
The float is accommodated in a guide body on which the float is loosely supported.
A liquid level detection device, which is mounted on a mounted circuit board . 2. A float having a magnet, a plurality of reed switches opened and closed by magnets of the float, and a resistor connected in series to at least one reed switch of the plurality of reed switches. A series circuit of a switch or a reed switch and a resistor is connected in parallel, the parallel circuit is connected to a connector, and a liquid level discriminating device which receives an electric signal generated at an output side of the connector as an input is provided, and Switch, resistor and connector
The float is accommodated in a guide body on which the float is loosely supported.
A liquid level detection device, which is mounted on a mounted circuit board .