JP3069461B2 - Gas Pressure Fluctuation Detection Method in Gas Meter with Mechanism to Detect Gas Supply Pressure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a slight change in gas supply pressure in order to determine a gas leak.

[0002]

2. Description of the Related Art A general household gas meter has a built-in safety mechanism that detects a gas supply pressure by a pressure switch, and when the pressure switch is operated, a shutoff valve is closed to stop the gas.

[0003]

However, in the case of the above prior art, since the pressure switch has only a function of detecting a constant lower limit pressure (set pressure) and outputting a signal, this pressure switch is Cannot detect pressure fluctuations. Of course, it is possible to detect the pressure fluctuation by replacing the pressure switch with a pressure sensor. However, the high-precision pressure sensor capable of detecting even minute pressure fluctuations has a large influence of noise, and there is a problem that the minute pressure fluctuations are buried in the noise, and cannot be used as it is.

An object of the present invention is to prevent a minute pressure fluctuation signal from being buried in noise when detecting a supply pressure using a high-precision pressure sensor.

[0005]

The gas pressure fluctuation detecting method according to the present invention is as follows.

[0006] By performing moving average processing of a plurality of pressure fluctuation data obtained from a target gas supply pressure detection sensor, the amplitude of the pressure fluctuation is successively smoothed so as to be larger than noise, and the smoothed data is smoothed. A gas pressure fluctuation detecting method for a gas meter having a mechanism for detecting a gas supply pressure for sequentially adding the primary differential values of the above and determining that the pressure fluctuation has occurred when the added value exceeds a certain range.

[0007]

When the signal output from the pressure sensor includes noise, the noise has whiteness. First, a plurality of pressure fluctuation data are obtained, and a moving average process is performed to obtain the pressure fluctuation. Are successively smoothed so that the amplitude of the signal becomes larger than the noise. The primary differential value (deviation from the previous data) of the smoothed data obtained as a result is sequentially added, and when this added value exceeds a certain range, it is determined that there is a pressure fluctuation. This threshold value is determined by the characteristics of the noise, the fluctuation width required to be detected, and the like. When the pressure fluctuation is detected, the added value is initialized. All of the above calculations are processed by a calculation circuit (microcomputer).

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. First, a gas pressure value including noise is detected by a pressure sensor. As shown in FIG. 2, this signal cannot be distinguished from a true gas pressure fluctuation and noise. Therefore, a plurality of, for example, ten pieces of data are taken, a moving average process is performed on the ten pieces of data, and the data is sequentially smoothed so that the amplitude of the pressure fluctuation becomes larger than the noise. FIG. 3 shows a waveform obtained by taking the moving average.

Next, the primary differential value (deviation from the previous data) of the smoothed data is sequentially added (FIG. 4), and when the added value exceeds a certain range, it is determined that there is a pressure fluctuation. I do. This threshold value is determined by the characteristics of the noise, the fluctuation range to be detected, and the like. When a true pressure fluctuation is detected in this way, a process for determining a gas leak is performed, and then an initialization process is performed. .

[0010]

As described above, according to the present invention, since the fluctuation of the gas supply pressure which is not affected by the noise can be detected, it is possible to determine the gas leakage by utilizing the minute fluctuation of the gas supply pressure. .

Further, since the present invention can design an electronic circuit that starts operating only when a pressure fluctuation occurs, power consumption can be saved as much as possible, and thus, a small battery can be used.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a detection method according to the present invention.

FIG. 2 is an explanatory diagram of a pressure measurement value including noise.

FIG. 3 is an explanatory diagram of a waveform obtained by taking a moving average.

FIG. 4 is an explanatory diagram of an added value of a deviation.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01F 3/22 G01F 1/00 G01M 3/26 F17D 5/02

Claims (1)

(57) [Claims] 1. A moving average process of a plurality of pressure fluctuation data obtained from a target gas supply pressure detection sensor is performed so that the amplitude of the pressure fluctuation is successively smoothed so as to be larger than noise, and the smoothing is performed. Pressure fluctuation detection method for a gas meter having a mechanism for sequentially adding primary differential values of coded data and detecting a gas supply pressure that determines that there has been a pressure fluctuation when the added value exceeds a certain range.