JP2503454Y2 - Electronic water meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an electronic water meter.

[Conventional technology]

As shown in FIG. 9, the electronic water meter converts the rotation of the impeller 3 rotating in the flow path 2 of the metal lower case 1 into an electric signal, performs arithmetic processing in an electronic circuit, and uses water. The amount is digitally displayed on the liquid crystal display. A magnet 4 is attached to the upper part of the shaft of the impeller 3 and a rotating magnetic field is generated when the impeller 3 rotates. The indicating mechanism 5 detects the rotating magnetic field of the magnet 4 and converts it into an electric signal, an electronic circuit that calculates the water consumption by calculating the electric signal of the magnetic sensor, and digitally displays the water consumption. The liquid crystal display, the magnetic sensor, the electronic circuit, and the battery for supplying power to the liquid crystal display, etc., are housed in an indicator case made of a thin metal plate. A window glass is provided for reading the amount of water used which is digitally displayed on the. FIG. 9 shows the magnetic sensor 7 disposed inside the bottom surface 6a of the indicator case 6, but the electronic circuit, the liquid crystal display, the battery, etc. are stored at other positions in the indicator case 6, Not shown in the figure. 8 is a metal inner case that fits inside the upper part of the lower case 1,
An adjuster 9 is attached to the lower surface thereof. Further, the inner case 8 rotatably supports the upper part of the shaft of the impeller 3 at the central portion thereof. A metal upper case 10 is screwed to the upper outer periphery of the lower case 1. Reference numeral 11 denotes an annular gasket that seals the upper ends of the lower case 1 and the inner case 8 in a watertight manner, and is fastened by the upper case 10. The indicator mechanism 5 is housed and mounted in the inner case 8 and the upper case 10 by pressing the collar 6b of the indicator case 6 with the indicator retainer 13 via the O-ring 12. The instruction presser 13 is attached to the upper part of the upper case 10 by the instruction presser ring 14. The instruction pressing ring 14 is screwed to the upper case 10. Reference numeral 15 is a lid which is attached to the instruction presser 13 by a pin 16 so as to be openable and closable, and is normally closed as shown in the drawing and opened at the time of meter reading. Reference numeral 17 is a cord for connecting an electronic circuit housed in the indicator case 6 to a communication line such as a telephone line, which has a connector 18 at one end and is connected to an airtight terminal penetrating the indicator case 6 at the other end. The electronic circuit in the indicator case 6 is electrically connected via the airtight terminal.

[Problems to be solved by the device]

In the above-mentioned conventional technique, the metal instruction case 6 accommodating the magnetic sensor, the electronic circuit, the liquid crystal display, the battery, etc. is electrically connected to the water pipe through the metal inner case 8 and the lower case 1. Since it is grounded, if a lightning surge from the cord 17 enters the electronic circuit in the indicator case 6, a surge current flows from the metallic indicator case 6 through the inner case 8 and the lower case 1 to the ground, and the liquid crystal display disappears. However, there is a problem that such a failure is likely to occur.

In view of the above, it is an object of the present invention to provide an electronic water meter that is resistant to electrical noise such as lightning surge, electromagnetic waves and static electricity.

[Means for solving the problem]

In order to achieve the above object, an electronic water meter of the present invention includes a magnetic sensor (30) for detecting rotation of a magnet (23) attached to an impeller (22) and converting the magnetic sensor (30) into an electric signal. A liquid crystal display equipped with a printed wiring board (31) mounted with an electronic circuit for calculating the water consumption by calculating the water consumption by calculating the electric signal of (30), a liquid crystal display (32) for displaying the water consumption and a battery (33). A conductive inner case (60) having a unit (29) and accommodating the liquid crystal indicating unit (29) and having a window for visually recognizing the liquid crystal display (32) is provided in the upper part. Case (60)
Is covered with an insulating resin case (61), and a cable (5
1), and one of the core wires of the cable (51) is electrically connected to the inner case (60).

[Action]

A liquid crystal indicating unit including a magnetic sensor, an electronic circuit, a liquid crystal display, a battery and the like detects the rotating magnetic field of the magnet of the impeller and digitally displays the amount of water used, as in the prior art. The LCD indicator unit is housed in a conductive inner case, which is surrounded by a resin case and window glass, and one of the core wires of the cord is electrically connected to the inner case. Even if a high voltage such as a lightning surge is applied, the withstand voltage between the resin case and the window glass prevents the surge current from flowing to the ground. or,
It acts as a conductive inner case or an electrostatic shield.

〔Example〕

In FIG. 1, 20 is a metal lower case, and its flow path
An impeller 22 is rotatably provided inside 21. 23 is a magnet mounted on the upper portion of the shaft 22a of the impeller 22, and the shaft 2
It is magnetized in the diametrical direction perpendicular to the axis of 2a. Reference numeral 24 is a pivot support fixed to the lower case 20, and the pivot 25 is screwed to the pivot support and fixed by a nut 26.
The impeller 22 is rotatably supported by the pivot 25. 27 is a strainer provided at the inlet of the flow path 21, 28 is a cylindrical magnetic seal made of a thin magnetic material that is fitted and fixed inside the lower case 20, and the magnetic field from the outside of the meter affects the magnet 23. Prevent from doing.

Reference numeral 29 is a liquid crystal indicating unit, which is a magnetic sensor 30 that detects a rotating magnetic field of the magnet 23 and converts it into an electric signal, and a printed wiring that is mounted with an electronic circuit that arithmetically processes the electric signal of the magnetic sensor 30 to calculate the water consumption A board 31, a liquid crystal display 32 mounted on this printed wiring board to digitally display the amount of water used, a battery 33 for supplying power to a magnetic sensor or an electronic circuit, a magnetic sensor 30, a printed wiring board 31 and a battery 33 are fixedly mounted. It is composed of a resin frame 34. Reference numeral 35 is a conductive spring plate for electrically connecting the ground circuit of the printed wiring board 31 to a lower inner case described later.

36 is a lower inner case, which is made of a copper plate with a thickness of 0.5 mm and has a generally bottomed cylindrical shape.
have. 37 is also an upper inner case formed of a 0.5 mm thick copper plate and has a brim 37a on the lower end outer periphery,
A D-shaped opening as a window is provided in the upper center part.

The upper inner case 37 has a D-shaped opening 37b as a window on its upper surface as shown in FIG. 5 (a), and has an electronic circuit of the liquid crystal indicating unit 29 as will be described later and a telephone line outside the meter. Three holes a, b, and c for passing the terminals of the cord to be connected to etc. are opened in the flat portion of the upper surface.
An enlarged view of these holes is shown in FIG. 5 (b). The holes a and b have a large diameter and the hole c has a small diameter, but arcuate notches d, d are provided so as to surround the hole c. The notches d, d are holes of this shape. Therefore, a round edge e is formed around the hole c, and bridges f, f extending from the edge e in the diameter direction of the hole c are formed. The operation of these holes, edges and bridges will be described later.

Referring again to FIG. 1, reference numeral 38 denotes a first window glass, which is made of a colorless and transparent resin and is disposed inside the upper inner case 37. Reference numeral 39 denotes a first gasket made of an elastic material, which is interposed between the lower surface of the peripheral edge of the opening surrounding the opening 37b of the upper inner case 37 and the first window glass 38 as illustrated. Reference numeral 40 denotes a second gasket formed of the same material as that of the gasket 39 and having the same shape. The second gasket 40 is interposed between the upper surface of the peripheral edge of the opening of the upper inner case 37 and the lower surface of the second window glass 41. There is. The second window glass 41 is made of tempered glass and is D-shaped when viewed from above (see FIG. 6).

As shown in FIGS. 7 (a), (b) and (c), the first window glass 38 has a D-shaped groove 38a into which the first gasket 39 is inserted (as viewed from the top) and an inner side of the groove 38a. When the first gasket 39 is positioned, the bank 38b for preventing the gasket from escaping so as not to escape inward of the D-shape of the groove when the first gasket 39 is compressed in the vertical direction, and the first gasket 39 is compressed. There is a bank 38c that prevents the escape so that it does not sometimes escape to the outside of the groove 38a. The banks 38b and 38c may not be formed integrally with the first window glass 38, but may be formed separately. The inner bank 38b functions to prevent the second gasket 40 from escaping laterally inward. The height of the bank 38b, that is, the height from the bottom surface of the groove 38a to the top surface of the bank 38b is the thickness of the upper inner case 37 (0.5 mm).
And the height (thickness) of the gaskets 39 and 40 when they are not compressed, and the compression margin of both gaskets is subtracted. Reference numeral 38d is a leg portion projecting downward from three outer peripheral portions of the first window glass 38, and the leg portion 38d is engaged with the notch of the printed wiring board 31 during assembly to determine the relative position of the two.

Referring again to FIG. 1, reference numeral 42 designates an upper resin case made of electrically insulating plastic, which covers the outer circumference of the upper inner case 37 via an O-ring 43.
Loosely fitted from above 37. In practice, the upper resin case 42 is fitted into the upper inner case 37 before the second window glass 41 is placed on the second gasket 40, and then the second window glass 41 is fitted. The second gasket 40
Placed on the upper surface of the first window glass 38, the first gasket 39, the upper inner case 37, the second gasket 40,
O-ring 43, upper resin case 42 and second window glass 41
Put the combination of the above into the vacuum chamber, and the second window glass
Place the weight on top of 41. In this way, the air in the space 44 between the first window glass 38 and the second window glass 41 is decompressed to a high vacuum (about 50 mmHg or less). By doing so, the first and second gaskets 39, 40 are compressed in the vertical thickness direction, and are brought into close contact with the first and second window glasses 38, 41 and the upper inner case 37 to maintain airtightness. After that, when the pressure in the vacuum chamber is returned to the atmospheric pressure, the combination of these window glasses 38 and 41 is not attracted to each other (pressed by the atmospheric pressure, rather than being separated), and the assembled state is maintained. . In this way double glazing windows can be easily made without the use of glue.
45 is a glass presser made of resin, and the protrusion 45a on the lower surface thereof is put into the groove on the upper surface of the resin case 42 and ultrasonically welded together to form one body.The glass presser presses down the outer periphery of the upper surface of the window glass 41. Press to. Reference numeral 46 is a lid attached to the glass presser 45 so as to be openable and closable.

In the upper resin case 42, a portion 42a surrounding the second gasket 40 is formed in a D shape when viewed from above so that the gasket does not spread laterally outward when the second gasket 40 is compressed. . A D-shaped opening 42a 'surrounded by this portion 42a is provided as shown in FIG. Further, as is clear from FIG. 8, holes 42b, 42c and 42d for inserting terminals described later are formed in the resin case 42. And cylindrical hanging portions 42b 'and 4 surrounding holes 42b and 42c.
2c 'are formed. Note that 42c 'does not appear in FIG. 8 (c), but is shown in FIG. Drooping part 42
The b'and 42c 'are fitted in the holes a and b of the upper inner case. As shown in FIG. 4, terminals 47 are provided in the holes 42b and 42c.
And 48 are inserted, and the lower ends of terminals 47 and 48 are printed wiring boards.
Soldered to 31. The terminal 49 is inserted through the hole 42d of the upper resin case 42 and the hole c of the upper inner case 37, and is soldered to the round edge e formed around the hole c of the upper inner case 37. It is attached. The lower end of the terminal 49 is soldered to the ground circuit of the printed wiring board 31. 50 is terminals 47, 48, 49 and upper resin case
It is three O-rings provided between 42 and. Reference numeral 51 is a cord for connecting the electronic circuit of the liquid crystal indicating unit 29 to a telephone line outside the meter, and its core wires 52, 53, 54 are terminals 47, 4 respectively.
Soldered to the upper end of 8,49 as shown in FIG. The core wire 54 is a ground wire. 55 is a filling material of electronic insulating resin, as shown in FIG. 1, the upper end of the terminals 47, 48, 49 and the cord.
It is filled in the soldering part with the core wire of 51. A terminal cover 56 is filled with the filling material 55 and then fixed by covering the upper resin case 42. Reference numeral 57 is a similar filling material, and as shown in FIGS. 1 and 4, it is filled inside the upper inner case 37 around the terminals.

The lower inner case 36 accommodates the liquid crystal indicating unit 29 in a space formed by the upper inner case 37, and the lower and upper inner cases 36 and 37 have flanges 36a and 37a, respectively. As shown in FIG. Then, a gasket 58 is fitted to this joint portion, a lower resin case 59 is fitted so as to cover the gasket 58 and the lower inner case 36, and the outer edge of the upper end of the resin case 59 and the upper resin case 42 are The outer periphery of the lower end is integrally joined by ultrasonic welding.

In this way, the conductive upper inner case 37 and the lower inner case 36 are integrally joined to form the inner case 60, and the insulating upper resin case 42 and the lower resin case 42 are formed. 59 and 59 are welded together to form a resin case 61. In this way, the cord 51 for connecting to the outside comes out from the one in which the insulating resin case 61 surrounds the outer periphery of the conductive inner case 60 that houses the liquid crystal indicating unit 29. The resin case 61 is inserted inside the lower case 20 of the meter, and is fastened with the upper case 62 made of metal. Reference numeral 63 is a nail for preventing rotation of the resin case 61, 64 is an O-ring inserted between the lower case 20 and the resin case 61, and the upper case 62 is screwed to the lower case 20. 65 is a screw 66 and the lower resin case 59
It is an adjuster attached to the lower surface of the.

[Effect of device]

Since the electronic water meter of the present invention is configured as described above, the resistance to electrical noise such as lightning surge and static electricity is improved. That is, by surrounding the outer circumference of the conductive inner case with the insulating resin case, it is possible to prevent the surge current from flowing to the ground due to the withstand voltage of the resin case. Therefore, a fatal failure such as disappearance of the liquid crystal display can be prevented.

[Brief description of drawings]

1 is a vertical front view of an electronic water meter, FIG. 2 is a top view, and FIG. 3 is a top view with a lid of a liquid crystal display and a lid of a terminal part removed. Partial view, FIG. 4 is an enlarged view of a section 4-4 in FIG. 3, FIGS. 5 (a) and 5 (b) are a top view of an upper inner case and an enlarged view of a part thereof, and FIG.
The figure shows a top view of the second window glass, and FIGS. 7 (a) and 7 (b).
(C) is a top view and a left side view of the first window glass, and a sectional view taken along the line CC in FIG. 8 (a), and FIGS. 8 (a), (b) and (c) are top views of the upper resin case. And C in the front view and FIG.
-C sectional drawing and FIG. 9 are some longitudinal front views of the conventional electronic water meter. 20 …… Lower case, 22 …… Impeller, 23 …… Magnet, 29
…… Liquid crystal indicator unit, 30 …… Magnetic sensor, 32 …… Liquid crystal display, 33 …… Battery, 41 …… Window glass, 51 …… Cable, 60 …… Inner case, 61 …… Resin case, 62 …… Upper case

Claims (1)

(57) [Scope of utility model registration request] 1. A magnet (23) attached to an impeller (22).
Magnetic sensor (30) that detects the rotation of the rotor and converts it into an electrical signal
And a printed wiring board (31) on which an electronic circuit for calculating the amount of water used by calculating the electric signal of the magnetic sensor (30) is calculated, a liquid crystal display (32) for displaying the amount of water used, and a battery (33). A conductive inner case (60) having a liquid crystal indicating unit (29) provided with, and having a window for accommodating the liquid crystal indicating unit (29) and visually recognizing the liquid crystal display (32) at an upper portion thereof. And install this inner case (60)
It has a cable (51) which is covered with an insulating resin case (61) and connects the electronic circuit to the outside of the meter, and one of the core wires of the cable (51) is provided in the inner case (60). An electronic water meter characterized by being electrically connected.