JP3601897B2 - Gas meter - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gas meter including a terminal group for connecting an external device such as a gas leak alarm. More specifically, the present invention relates to a wiring structure for lightning surge suppression performed on a terminal group.
[0002]
[Prior art]
As shown in FIG. 1, the gas meter 1 has a case main body 10 including a lower case 101 and an upper case 102. The case main body 10 has a gas inlet 2 and a gas pipe 12 to which a gas pipe 11 is connected. A gas outlet 3 to be connected is formed. In the gas meter main body 10, two measuring chambers (not shown) are formed in a gas passage extending from the gas inlet 2 to the gas outlet 3, and these measuring chambers alternate between a gas inflow state and a gas outflow state. As a result, the diaphragm in the measuring chamber is activated, and the gas flow rate can be detected based on this.
[0003]
A gas leak alarm and an external device such as a terminal transmission device for transmitting gas flow rate information such as a gas flow rate measured by the gas meter 1 to a predetermined destination via a telephone line are provided on the lower front side of the lower case 101. A terminal block 20a for wiring and connecting the device to the gas meter 1 is formed.
[0004]
As shown in FIGS. 4A and 4B, the terminal block 20a includes a plurality of terminal groups electrically connected to the microcomputer controller 6, a ground terminal G, and a surge countermeasure terminal. F and the like. In the terminal group configured in the terminal block 20a, the terminals N1 and N2 are a pair of terminals N for connection of the terminal transmission device, and the terminals S1, S2 and S3 are a shut-off valve provided in the gas meter. Terminal pair S for connecting an externally connected device to be remotely controlled, terminals K1 and K2 are a terminal pair K for connecting a gas leak alarm, and terminals T1 and T2 are for connecting other externally connected devices. Terminal pair T for performing the operation. Two surge absorbing elements 21 (surge absorbing circuits), such as varistors, are electrically connected between the terminals N1 and N2.
[0005]
Similarly, the surge absorbing element 21 is electrically connected to the other terminal pairs. Here, when the gas leak alarm 24 is connected to the gas meter 1, in order to protect the microcomputer controller 6 from lightning surge, an electrical system is insulated from the surroundings (float state) or a method of lightning surge is used. If a system having a bypass is used, and the insulation system is used, the gas leak alarm 24 is connected to the terminals K1 and K2 by wiring.
[0006]
[Problems to be solved by the invention]
However, when trying to unify only the terminal block 20a having a structure suitable for a method of providing a lightning surge bypass in the above-described gas meter 1, there is a case where an insulating method must be used depending on the type of external equipment. 20a has a problem that it cannot be unified into a structure suitable only for one lightning surge protection measure.
[0007]
In view of the above problems, an object of the present invention is to provide a gas meter provided with a terminal group that can easily cope with both the insulation method and the bypass method when protecting from lightning surge.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, according to the present invention, in a gas meter having a terminal group for inputting / outputting a signal to / from an external device such as a gas leak alarm, the terminal group includes an input / output with the external device. A pair of input / output terminals to which wires are respectively routed, a common terminal electrically connected to each terminal of the pair of input / output terminals, and a bypass connection for grounding each of the pair of input / output terminals via a surge absorbing circuit. Terminals, and the bypass connection terminal and the common terminal are electrically short-circuited and opened according to an external device to be connected by a short-circuiting piece detachable from these terminals. It is characterized in that it can be switched to the state in which it has been performed.
[0009]
With this configuration, if the common terminal and the bypass connection terminal are electrically short-circuited by the shorting piece, a lightning surge bypass is configured for any of the input / output terminal pairs. Protection can be provided. In addition, since the short-circuiting piece is detachable to the last, if it is removed, the common terminal and the bypass connection terminal can be opened. Therefore, when it is necessary to take measures against lightning surge in an insulated state, it is only necessary to remove the short-circuit piece.
[0010]
In the present invention, it is preferable that the bypass connection terminal and the common terminal are configured at adjacent positions so that the short-circuit piece can be easily attached and detached.
[0011]
In the present invention, the terminal group is configured, for example, on a terminal block in which each terminal is arranged.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
(Overall configuration of gas meter)
FIG. 1 is a front view showing the gas meter of the present embodiment. Since the gas meter of the present embodiment has the same basic configuration as the conventional gas meter, the corresponding parts are denoted by the same reference numerals and detailed description thereof will be omitted. That is, the gas meter 1 of this example also has a case main body 10 including a lower case 101 and an upper case 102, and the gas inlet 2 to which the gas pipe 11 is connected and the gas pipe 12 are connected to the case main body 10. Gas outlet 3 is formed. In the gas meter main body 10, two measuring chambers (not shown) are formed in a gas passage extending from the gas inlet 2 to the gas outlet 3, and these measuring chambers alternate between a gas inflow state and a gas outflow state. As a result, the diaphragm in the measuring chamber is activated, and the gas flow rate can be detected based on this.
[0014]
The lower end of the lower case 101 has a gas leak alarm and an external connection such as a terminal transmission device for transmitting gas flow rate information such as gas flow rate measured by the gas meter 1 to a predetermined destination via a telephone line. A terminal block 20 having a terminal group for wiring and connecting devices to the gas meter 1 is configured.
[0015]
(Configuration of terminal block)
FIG. 2A is an enlarged front view showing a terminal block provided in the gas meter of the present embodiment.
[0016]
As shown in FIG. 2A, the terminal block 20 of the present example includes an upper terminal block 201 and a lower terminal block 202. In the upper terminal block 201, terminal groups of a type in which a crimp terminal of input / output wiring of an external connection device is fixed to a terminal plate 203 having a screw hole with screws 204 are formed at substantially equal intervals. ing.
[0017]
In the upper end terminal block 201, terminals S1, S2, and S3 for wiring connection of an external device for remotely operating a shut-off valve provided in a gas passage of the gas meter 1 are provided on the right end side in the drawing. Are formed. At a position adjacent to the terminal pair S, a terminal for wiring connection with a terminal transmission device (external device) for transmitting gas flow information such as gas flow measured by the gas meter 1 to a predetermined destination via a telephone line. A terminal pair N composed of N1 and N2 is configured. At positions adjacent to the terminal pair N, terminals J and F, which will be described later, are configured in this order.
[0018]
In this example, the terminal J and the terminal F are formed at adjacent positions on the terminal block 20, and can be easily short-circuited by the short-circuit piece 30. The short-circuit piece 30 is formed with an interval equal to the distance between the terminal J and the terminal F, and connects the two connection portions 301 fixed to the terminal plate 203 with screws 204, and connects the two connection portions 301. And a connecting portion 302. The short-circuit piece 30 is made of a metal plate, and can be easily attached to and detached from the terminal block 20 only by handling the screws 204.
[0019]
The short-circuit piece 30 may be a short-circuit piece 31 having a structure in which crimp terminals 312 are formed at both ends of a lead 311 as shown in FIG. 2B.
[0020]
Similarly to the terminal block 201 on the lower end side, a terminal of a type in which a crimp terminal for input / output wiring of an external device is fixed to the terminal plate 203 having a screw hole with the screw 204, similarly to the upper end side terminal block 201 The groups are formed at substantially equal intervals. In the lower end side terminal block 202, two terminal pairs T composed of terminals T1 and T2 for wiring and connecting the gas meter 1 and an external device used for a predetermined application are arranged at the right end as viewed in the drawing. ing. At a position adjacent to the terminal pair T, a terminal pair composed of terminals K1 and K2 for wiring connection of a gas leak alarm (external device) for inputting a gas leak signal to a microcomputer controller built in the gas meter 1. K is configured. At a position adjacent to the terminal pair K, a ground terminal G is formed with a width of substantially one terminal.
[0021]
(Electrical connection of terminal block)
FIG. 3 is a circuit diagram showing an electrical connection relationship of the terminal block of the present example. In describing the electrical connection, external devices such as a terminal transmission device are connected to each terminal by wiring.
[0022]
In the terminal block 20, first, the ground terminal G and the terminal F are electrically connected via a surge absorbing circuit 21A using a surge absorbing element such as a varistor.
[0023]
A terminal transmission device 22 provided externally is wired and connected to the terminal pair N (terminals N1 and N2), and the terminals N1 and N2 of the terminal pair N are connected to the microcomputer controller 6 attached to the gas meter. Each is electrically connected. A surge absorbing circuit 21B using a surge absorbing element such as a varistor is electrically connected to each of the terminals N1 and N2. A connection point a between these two surge absorbing circuits 21B is electrically connected to a terminal J. It is connected. This surge absorbing circuit 21B is a circuit for preventing the current from flowing toward the microcomputer controller 6 when an overcurrent due to a lightning surge occurs at the terminal N1, as in each of the surge absorbing circuits described later.
[0024]
The terminals K1 and K2 of the terminal pair K and the terminals T1 and T2 of the terminal pair T have the same circuit configuration as the terminals N1 and N2 of the terminal pair N. That is, the terminal pair K is wired and connected to the gas leak alarm 24 provided outside, and the terminals K1 and K2 of the terminal pair K are electrically connected to the microcomputer controller 6, respectively. A surge absorbing circuit 21B is electrically connected to each of the terminals K1 and K2, and a connection point b between these two surge absorbing circuits 21B is also electrically connected to the terminal J. The terminal pair T is wired and connected to external devices 25 and 26 provided outside, and the terminals T1 and T2 of the terminal pair T are electrically connected to the microcomputer controller 6, respectively. A surge absorption circuit 21B is electrically connected to each of the terminals T1 and T2, and connection points c and d of these two surge absorption circuits 21B are also electrically connected to the terminal J.
[0025]
Further, the terminal pair S is wired and connected to a remote shutoff valve opening / closing device 23 provided outside, and the terminals S1, S2, and S3 of the terminal pair S are electrically connected to the microcomputer controller 6, respectively. Here, the terminal S2 is a common in the terminal pair S. Two surge absorbing circuits 21B are electrically connected to each of the terminals S1 and S2, and a connection point e of these two surge absorbing circuits 21B is electrically connected to a terminal J. The surge absorbing circuit 21B is also electrically connected between the terminals S2 and S3.
[0026]
Thus, the terminal J is a common terminal that is electrically connected to each terminal of the input / output terminal pair with each external device via the surge absorbing circuit 21B. The terminal F is connected to the ground terminal G (ground potential) via the surge absorbing circuit 21A. Are terminals connected to the ground via the surge absorbing circuits 21A and 21B to constitute a bypass for discharging a lightning surge.
[0027]
In the terminal block 20 configured as described above, first, the terminal J and the terminal F are electrically short-circuited by the short-circuit piece 30, and the terminal transmission device 22, the remote shutoff valve opening / closing device 23, the gas leak alarm 24, and the like. Thus, a bypass for lightning surge from each pair of input / output terminals to the ground terminal G via the terminals J and F via the surge absorbing circuits 21A and 21B is formed. Therefore, for example, a lightning surge that has entered through the gas leak alarm 24 or the like, as indicated by the arrow Y, indicates the surge absorbing circuit 21B, the connection point b, the terminal J, the shorting piece 30, the terminal F, and the surge absorbing circuit 21A. Through the terminal G (ground). Even when a lightning surge enters another terminal, the terminal G (ground) passes through each surge absorbing circuit 21B, connection points a, c, d, and e, terminal J, shorting piece 30, terminal F, and surge absorbing circuit 21A. ). Therefore, the microcomputer controller 6 of the gas meter 1 can be protected from lightning surge.
[0028]
In addition, among the external devices (including the terminal transmission device 22, the remote cutoff valve opening / closing device 23, and the gas leak alarm 24), devices that cannot be used in the bypass structure and have restrictions such as an insulating structure are used. in this case, only removing the jumper 30, it is possible to the terminal J and the terminal F to the open state, the bypass is shut off, it is possible to perform lightning surge insulation structure.
[0029]
As described above, in the gas meter 1 of the present embodiment, electrical connection is made between the respective terminals (K1, K2,...) Of the input / output terminal pair such as the gas leak alarm 24 via the surge absorbing circuit 21A. A terminal F (bypass connection terminal) which forms a bypass for releasing a lightning surge by grounding each of the common terminal (terminal J) and input / output terminals to / from external equipment via the surge absorbing circuits 21A and 21B. Means that these terminals can be switched between an electrically shorted state and an open state by a detachable shorting piece 30. Therefore, when the common terminal (terminal J) and the terminal F for bypass connection are electrically short-circuited by the shorting piece 30, the lightning surge is applied to any of the input / output terminal pairs (K1, K2,...). , A protection from lightning surge can be provided. In addition, since the short-circuit piece 30 is detachable to the last, if it is removed, the common terminal (terminal J) and the terminal F for bypass connection can be opened. Therefore, if it is necessary to use the device in an insulated state, it is possible to take measures against lightning surge in the insulated state only by removing the short-circuit piece.
[0030]
Moreover, since the common terminal (terminal J) and the terminal F for bypass connection are formed at adjacent positions, there is an advantage that the short-circuit piece 30 can be easily attached and detached and does not hinder other wiring connections. .
[0031]
【The invention's effect】
As described above, in the gas meter according to the present invention, the common terminal electrically connected to each terminal of the input / output terminal pair such as the gas leak alarm device, and each of the input / output terminal pair is connected via the surge absorbing circuit. The bypass connection terminals for grounding are characterized in that they can be switched between an electrically short-circuited state and an open state by short-circuit pieces that are easily detachable from these terminals. Therefore, according to the present invention, when the common terminal and the bypass connection terminal are electrically short-circuited by the short-circuiting piece, a lightning surge bypass is configured for any input / output terminal pair. Provides protection from lightning surges. In addition, since the short-circuiting piece is detachable to the last, if it is removed, the common terminal and the bypass connection terminal can be opened. Therefore, it is possible to take measures against lightning surge in the insulated state only by removing the shorting piece.
[Brief description of the drawings]
FIG. 1 is a front view of a gas meter.
FIG. 2A is an enlarged front view showing a terminal block of a gas meter to which the present invention is applied and a short-circuit piece used for the terminal block, and FIG. 2B is an explanatory view of another short-circuit piece.
FIG. 3 is a circuit diagram showing an electrical connection relationship of a terminal block of a gas meter to which the present invention is applied.
FIG. 4 is a circuit diagram showing an electrical connection relationship between terminal blocks of a conventional gas meter.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gas meter 10 Case main body 20 Terminal block 21 Surge absorption circuit 22 Terminal transmission transmitter 23 Remote shutoff valve switch 24 Gas leak alarm 25, 26 External equipment 30, 31 Shorting piece F Terminal J for bypass connection To input / output terminal pair Common terminal

Claims (3)

In a gas meter having a terminal group for inputting and outputting a signal with an external device such as a gas leak alarm,
The terminal group includes an input / output terminal pair to which input / output lines to / from the external device are respectively wired, a common terminal electrically connected to each terminal of the input / output terminal pair, and each of the input / output terminal pair. And a common connection terminal for connecting the common terminal to the common terminal via a surge absorbing circuit. The bypass connection terminal and the common terminal are connected to each other by a detachable short-circuit piece with respect to these terminals. gas meter which is characterized in that are switchable to electrically shorted state and an open state according to. The gas meter according to claim 1, wherein the bypass connection terminal and the common terminal are configured at adjacent positions. 3. The gas meter according to claim 1, wherein the terminal group is configured on a terminal block in which the terminals are arranged. 4.

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