JP3064164B2 - Gas meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a gas meter for measuring the flow rate of the gas supplied at the upstream of the gas appliance gas stove or the like, in particular oxygen (O ₂₎ impurity is mixed components of the feed gas, such as The present invention relates to a gas meter having a function of shutting off a gas flow path when a concentration changes by a certain value or more.

[0002]

2. Description of the Related Art In general, a household gas meter has a function of measuring a flow rate of gas passing therethrough, detects a gas supply pressure by a pressure switch, and detects a pressure drop when the gas is not used. In the case, when a gas flow rate of a predetermined amount or more is detected using a flow meter, or when a gas flow rate is detected for a predetermined period or more, the gas shutoff valve is driven to close the gas flow path. I have. Thus, leakage is detected in the pipe or unnatural gas outflow, thereby preventing accidents before they occur and ensuring safety.

[0003]

As described above, the conventional gas meter has a function of detecting a leak in a pipe or an unnatural outflow of gas and operating a safety mechanism to prevent an accident from occurring. However, no safety measures were taken for the type of gas. For example, in an area where a gas component is determined in advance, a conventional gas meter passes gas regardless of the type of gas. For this reason, even if an abnormality occurs in the supply system due to some accident and oxygen is mixed in the supply gas pipe and the mixing ratio of the supply gas changes, or even if impurities are mixed, without detecting it, Gas was supplied as long as there was no leakage of piping or use of unnatural gas.

However, in this type of gas meter,
Even when the concentration of oxygen in the supply gas changes and the mixing ratio changes, or when the gas components change due to contamination with impurities, the combustion performance of the gas appliance will be impaired. There was a problem that it would be dangerous if continued.

The present invention has been made in view of the above problems, and has as its object to cut off the supply of gas to a gas appliance when an impurity gas such as oxygen having a predetermined concentration or more is mixed in a gas flow path. It is an object of the present invention to provide a gas meter capable of preventing an accident caused by a change in component concentration.

[0006]

According to a first aspect of the present invention, there is provided a gas meter comprising: a gas passage through which a combustible supply gas passes; a gas blocking valve provided in the gas passage; A semiconductor element for detecting a component concentration of the supply gas by a change in electric resistance value caused by gas adsorption, and the valve element when a component concentration of the supply gas detected by the semiconductor element reaches a predetermined value. And a gas shut-off means for shutting off the gas flow path.

In this gas meter, the component concentration of the supplied gas is detected by a change in the electric resistance value of the semiconductor element, and when the component concentration reaches a predetermined value, the valve is closed and the gas flow path is shut off. As a result, inflow of flammable gas having different component concentrations into the gas appliance can be prevented, and an accident resulting from a change in component concentration can be prevented beforehand.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of a gas meter 10 according to one embodiment of the present invention. This gas meter 10
Is provided with a gas flow path 11 having a gas inlet 16 and a gas outlet 17. The flammable supply gas 20 such as city gas flows from a gas inlet 16 through a pipe (not shown), and is then supplied from a gas outlet 17 to a gas appliance such as a gas stove (not shown). In this gas flow path 11, in order from the gas inlet 16 side,
A semiconductor element 14 for detecting a combustible gas is provided together with a gas shutoff valve 12 for shutting off a gas flow path 11 when a gas supply system is abnormal and a gas flowmeter 13 for measuring a gas flow rate. .

The semiconductor element 14 is an oxide semiconductor (SnO)
₂ , ZnO or the like) is fixed on a massive sintered body or an insulating substrate to form a thin film, and a pair of electrodes is attached thereto. In the semiconductor element 14, the contact of the combustible gas with the surface causes a change in the electric resistance between the electrodes, and the change in the electric resistance can detect a change in the component of the gas.

FIG. 2 shows a specific configuration of the control unit 15 in the gas meter 10 of the present embodiment. The control unit 15 includes a CPU (central processing unit) 30. The CPU 30 is connected to each unit of the device via a bus. Among them, a ROM (read only memory) 31 stores a control program for preventing an accident caused by a change in the composition of the supply gas 20 as shown in a flowchart (FIG. 3) described later. A RAM (random access memory) 32 stores predetermined gas concentration data serving as a gas cutoff reference, and temporarily stores detection data from the semiconductor element 14 and the like. .

The input port 33 is an interface for sending each output signal of the gas flow meter 13 and the semiconductor element 14 to the CPU 30. The CPU 30 controls the gas flow meter 13
When a gas amount equal to or more than a certain amount is detected by the output signal of the semiconductor device 14, a valve shutoff signal is output, and in response to the output signal of the semiconductor element 14, the concentration of a specific component such as oxygen in the supply gas 20 is monitored. When the component concentration exceeds a certain value, a valve shutoff signal is output. The output port 34 is an interface for sending the valve shutoff signal sent from the CPU 30 to the drive circuit 35. CPU 30
The drive circuit 35 that has received the valve shut-off signal sent from the controller closes the gas shut-off valve 12 and shuts off the gas flow path 11.

Next, the operation of the gas meter of this embodiment will be described with reference to FIG.
A description will be given along the flowchart shown in FIG. That is, the CPU 30 monitors the output signal of the semiconductor element 14 for detecting the flammable gas, and determines the component of the supply gas 20,
For example, the concentration of oxygen is detected (step S300).
Then, for example, oxygen gas is mixed in the gas flow path 11 through the upstream side of the piping of the gas meter 10, becomes the component concentration C given concentration C ₀ or a predetermined is (step S30
1; Y), the CPU 30 closes the gas shutoff valve 12,
The gas flow path 11 is shut off (step S302).

As described above, in the gas meter 10 of the present embodiment, the semiconductor element 14 for detecting the flammable gas is built in, and the component concentration of the supply gas 20 is detected by using the semiconductor element 14, and the component concentration is determined in advance. When the value exceeds a predetermined value, the gas flow path 11 is automatically shut off. Therefore,
Gases having different component concentrations are prevented from flowing into a gas appliance (not shown), thereby preventing an accident due to a change in component concentration. The operation when the gas flow rate becomes excessive is the same as that of the conventional gas meter, and the description thereof is omitted.

By the way, the mixing path of impurities such as oxygen gas into the gas meter 10 is not limited to the case where the impurities are mixed through the piping on the upstream side of the gas meter 10 as described above. In a so-called combined oxygen device in which the oxygen gas is mixed and supplied to the gas appliance as a mixed gas, the oxygen gas may flow backward from the mixer and be mixed in from the downstream side of the gas meter 10.

FIG. 4 shows a specific configuration of such a combined oxygen device. That is, the gas outlet 17 of the gas meter 10 is connected to one gas inlet 45 a of the mixer 45 via the gas stopper 41, the check valve 42, the governor (pressure regulator) 43 and the gas stopper 44. An oxygen cylinder 46 is connected to the other gas inlet 45 b of the mixer 45 via a gas stopper 47. Gas outlet 4 of mixer 45
5c is connected to a gas appliance 40 dedicated to mixed gas.

In this combined oxygen device, the supply gas 20 that has passed through the gas meter 10 is supplied to the mixer 45 after the pressure is adjusted to a constant value in the governor 43. The supply gas 20 is supplied to an oxygen cylinder 46 in a mixer 45.
After being mixed with oxygen gas 48 supplied from a predetermined ratio, it is supplied to gas appliance 40 as mixed gas 49,
The check valve 42 and the like are broken by an accident such as an earthquake, and the mixed gas 49
May flow back into the gas meter 10.

Even in such a case, since the semiconductor element 14 is built in the gas meter 10 in this embodiment, the concentration of the components in the mixed gas 49 can be detected. Therefore, the backflow of the mixed gas 49 due to an accident can be automatically detected based on the change in the component concentration, and the adverse effect can be prevented.

The present invention has been described with reference to the embodiments.
The present invention is not limited to the above-described embodiment, and can be variously modified without changing the gist thereof. For example, in the above embodiment, the example in which the present invention is applied to the combined oxygen device has been described.
Needless to say, the present invention can also be applied to a so-called compressed air combined device or the like in which 0 and compressed air are mixed and supplied.

[0020]

As described above, according to the gas meter of the present invention, the semiconductor element for detecting the flammable gas is incorporated, and the concentration of the component such as oxygen in the supply gas is changed by changing the electric resistance of the semiconductor element. When the change is detected and the component concentration reaches a predetermined value, the valve body is closed to shut off the gas flow path, thereby preventing an accident caused by the change in the component concentration of the supplied gas. Thus, there is an effect that safety is improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a gas meter according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a control unit of the gas meter of FIG.

FIG. 3 is a flowchart for explaining the operation of the gas meter of FIG. 1;

FIG. 4 is a diagram showing a system configuration in which the gas meter of FIG. 1 is applied to an oxygen coexisting device.

[Explanation of symbols]

 Reference Signs List 10 gas meter 11 gas flow path 12 gas shutoff valve (valve element) 13 gas flow meter 14 semiconductor element 20 supply gas (flammable gas)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-8624 (JP, A) JP-A-1-270631 (JP, A) JP-A-63-64978 (JP, U) 2534 (JP, B2) JP 4-20120 (JP, B2) JP 7-79842 (JP, B2) JP 5-77920 (JP, B2) (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01F 3/22 G01F 1/00 A62C 2/04 F17C 13/12 F23N 5/24 101

Claims (1)

(57) [Claims] A gas passage through which a combustible supply gas passes; a valve element provided in the gas passage for shutting off a gas; and a change in an electric resistance value caused by adsorption of the gas to a semiconductor surface. A semiconductor element for detecting a component concentration of the supply gas, and a gas shutoff for closing the valve body and shutting off a gas flow path when the component concentration of the supply gas detected by the semiconductor element reaches a predetermined value. And a gas meter.