JPH0363686B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas flow rate measurement method for measuring the consumption of gas, particularly household gas.

Conventionally, the gas flow rate measurement method for gas meters used to measure gas consumption in each household uses gas pressure to drive a built-in motion element, such as a rotor, and the number of motions of this motion element is used to measure the gas flow rate. It is now possible to find the total flow rate. Since this mover forms a measuring chamber equivalent to a square, there is a limit to its miniaturization. This results in a very large pressure loss, which has the disadvantage that practical miniaturization is limited to a certain extent.

The present invention has been made in view of the above-mentioned drawbacks, and, contrary to the conventional method of measuring the gas flow rate through an agitator driven by gas pressure, the present invention applies intermittent shocks to the gas flow itself. This paper proposes a method for measuring gas flow rate that can reduce the size of the measurement location without increasing pressure loss by measuring the gas flow rate when the gas flow disturbance caused by this impact moves a certain distance in the gas flow path. be.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on an example of the apparatus shown in the accompanying drawings.

In the figure, 1 is a gas flow path where gas flows in from one end (right side of the figure) and flows out to the other end (left side of the figure). Specifically, it can be easily installed in a part of household gas piping. be able to.

At a predetermined point A in the gas flow path 1, an impact device 2 is arranged which applies an impact to the gas flow in the gas flow path 1 at regular time intervals to cause intermittent turbulence in the gas flow. The turbulence of the gas flow caused by this impact device 2 can be caused by intermittently creating a pressure difference in the gas flow that continuously passes through point A in the gas flow path and adding pulsations to the gas flow. Some gas flows intermittently generate eddy flows. Specifically, as shown in the figure, a plate 3 parallel to the gas flow is arranged in the gas flow path 1, and when this plate 3 is intermittently rotated back and forth about an axis perpendicular to the flow direction of the gas flow, the gas flow is The flow area of channel 1 can be varied intermittently to cause the gas flow to pulsate, and although not shown, an orifice is provided in place of plate 3, and even if the orifice diameter is intermittently changed, the gas flow cannot be controlled. It can be made to pulsate. Also,
Since this plate 3 is accompanied by an obstacle in the gas flow, a Karman vortex train is generated on the downstream side of this plate 3, and the amount of vortex is intermittently changed by the intermittent rotation of the plate 3. Although not shown, if a rod that intermittently goes in and out of the gas flow path 1 is placed in place of the plate 3, it is possible to have a gas flow that has intermittently whirlpool portions. . Furthermore,
This impact device 2 may be of any type as long as the influence on the gas flow given at point A can be detected at point B, such as by intermittently injecting gas at point A.

At point B on the downstream side of point A in the gas flow path 1,
A detection device 4 is arranged to detect pressure fluctuations in the gas flow flowing from point A to point B or turbulence in the eddy flow. This detection device 4 can use a conventionally known pressure sensing element 5 to detect pressure fluctuations, and can use a strain gauge that changes the electrical resistance value by vibration or twisting to detect eddy flow. Alternatively, the pressure sensitive element 5 may be replaced with an antenna to read frequencies within a predetermined range due to the precession of the eddy current.

The above-mentioned detection device 4 is for detecting that the gas flow portion subjected to impact at point A has flowed to point B. Therefore, point A and point B are connected to the impact device 2.
The distance should be set so that there is no risk of the gas turbulent in the gas flow being transmitted even if the gas is stationary without flowing, and since the turbulence in the gas flow will decline as the gas flow continues, the distance should be set at the distance before this impact decays. is desirable. Note that when this detection device 4 detects the above-mentioned disturbance in the gas flow within a certain value range, it will be activated by a control panel 6, which will be described later.
It goes without saying that malfunctions can be prevented by outputting a single pulse signal.

When the detection device 4 detects disturbance in the gas flow, the control panel 6 converts the time required for the gas flow to travel between points A and B, calculates the gas flow rate, and displays the information on the display 7.
will be displayed.

That is, the gas flow flowing in the gas flow path 1 is A
If turbulence is caused at a point, and the time required for this turbulent part of the gas flow is calculated by dividing the distance between the gas flow and points A and B in gas flow path 1, then the total flow rate passing through gas flow path 1 can be calculated as follows: is what is required.

Since the gas flow rate measurement method of the present invention is as described above, the gas flow rate can be measured only with the impact device 2, the detection device 4, and the control panel 6, and these are not driven by gas pressure. Miniaturization is possible. In particular, pressure loss naturally occurs due to pulsation of the gas flow or generation of eddy flow by the impact device 2, or this pressure loss is much smaller than in the conventional example in which the motion element is driven by gas pressure.
The device can be made smaller without increasing pressure loss.

Furthermore, since the present invention reads the gas flow rate as an electrical signal, it consumes power, but it is also possible to display the measurement results remotely and aggregate the measured values online, so it is economical to reduce power consumption. It also has certain advantages.

[Brief explanation of drawings]

The drawing is a partially sectional front view of an example of an apparatus using the method for measuring gas flow rate of the present invention. 1 - Gas flow path, 2 - Impact device, 3 - Plate, 4 - Detection device, 5 - Pressure sensitive element, 6 - Control panel.

Claims (1)

[Claims] 1. At a predetermined point A in the gas flow path, impact is applied to the gas flow in the gas flow path at regular intervals to cause intermittent turbulence in the gas flow, and at a point B downstream from point A in the gas flow path. The gas flow rate is measured by detecting turbulence in the gas flow flowing from point A to point B, and calculating the flow velocity based on the time required to reach point B from point A. How to measure flow rate.