JPS62191748A - Apparatus for measuring gas-liquid mixing ratio - Google Patents

Abstract

PURPOSE:To make it possible to measure a gas-liquid mixing ratio with high accuracy even if the flow speed of a fluid changes without requiring the correction of the gas-liquid distribution in a pipe, by converting the detection value obtained by a pair of electrodes provided in the pipe to electrostatic capacity and operating the gas-liquid mixing ratio of the fluid using a predetermined formula. CONSTITUTION:An outside electrode 6 is provided to the outer periphery of the core 5 supported by the support 2 in a pipe 1 and an inside electrode 7 is provided to the inner periphery of the pipe 1 so as to allow an entire fluid F to pass through the space D constituted by the electrodes 6, 7. The electrodes 6, 7 are respectively connected to an electrostatic capacity converting part 8 and the detection values obtained from said electrodes are guided to be converted to the electrostatic capacity CM between the electrodes 6, 7 of the fluid F. The converted electrostatic capacity CM is guided to a gas-liquid mixing ratio operation part 9 to operate the gas-liquid mixing ratio of the fluid F using a predetermined formula.

Description

[Detailed description of the invention] - Industrial application field> The present invention is a gas-liquid mixture ratio measuring device configured to calculate the mixture ratio of gas and liquid in a fluid (hereinafter referred to as "gas-liquid mixture ratio"). Regarding.

<Prior Art> Hereinafter, a conventional gas-liquid mixture ratio measuring device of this type will be explained using a diagram illustrating an outline of a conventional gas-liquid mixing ratio measuring device shown in FIG.

Fluid F, which is a mixture of gas and liquid, flows inside the vibrator 1. Inside the pipe 1, there is provided a column 2 in which a gas-liquid mixture ratio measuring section is installed, for example, in the central position and in which a nermistor S and a heater H are arranged, for example. The heat generated in the heater 1 is transferred to the surrounding fluid F. The heat transfer coefficient at this time is the fluid F
It varies depending on the state of the gas-liquid mixture ratio. Therefore, by utilizing such characteristics, the gas-liquid mixture ratio calculating section 4 calculates and outputs the gas-liquid mixture ratio χ0 of the fluid by capturing the difference in heat transfer coefficient by the change in the resistance value of the thermistor S.

<Problems to be Solved by the Invention> By the way, in this conventional gas-liquid mixture ratio measuring device, there are restrictions on usage conditions because the heat transfer coefficient is affected by the flow velocity. Furthermore, since the fluid F has a phase yl (part i[) in the gas-liquid mixing ratio within the vibrator 1, there is a problem in that it is necessary to correct the distribution of this gas-liquid mixing ratio.

The present invention has been made in view of the problems of the prior art, and does not require correction of the air-liquid distribution within the pipe.
Another object of the present invention is to provide a gas-liquid mixture ratio measuring device that can measure the gas-liquid and 2-combination ratio with high accuracy even when the fluid flow rate changes.

Means for Solving the Problems> The gas-liquid mixture ratio measuring device of the present invention for achieving the above-mentioned object is configured such that the fluid can pass through a barb through which a fluid containing a mixture of gas and liquid flows. At least a pair of electrodes are provided, and a detected value detected by one electrode of the pair is converted into capacitance by a capacitance conversion section, and this capacitance is inputted to a gas-liquid mixture ratio calculation section to The system is configured to calculate and output the gas-liquid mixture ratio.

<Example> Hereinafter, an example of the present invention will be described using a block diagram of a gas-liquid mixture ratio measuring device shown in FIG. 1 showing a specific example of the present invention. Note that the parts in FIG. 1 that are the same as those in FIG. 4 are given the same numbers and their explanations will be omitted.

In FIG. 1, reference numeral 5 denotes a core supported by a support 2 within the pipe 1. A pair of electrodes consisting of an outer electrode 6 and an inner electrode 7 are provided on the outer periphery of the core 5 and an inner electrode 7 on the inner periphery of the pipe, respectively. All fluid F passes through.

The outer electrode 6 and the inner electrode 7 are each connected to a capacitance converter 8, and the first detection signal obtained from these electrodes is guided and converted into the capacitance CM between the electrodes of the fluid F. The converted capacitance WkCM is led to the gas-liquid mixture ratio calculating section 9, and the gas-liquid mixture ratio χ of the fluid F is calculated.

FIGS. 2(A) and 2(B) are diagrams for explaining the present invention, and the present invention will be further explained using FIG. 2.

Now, if we define the gas-liquid mixing ratio χ as the ratio of gas to the total volume of the fluid F, then the outer electrode 6a (6a shows the case where the outer electrode is considered as a flat electrode) and the inner electrode as shown in Fig. 1. 7a (However, 7a does not show the case where the outer electrode is considered as a flat plate electrode) The fluid F existing between 7a and 7a is a gas consisting of liquid 1:Q and bubbles (steam) FF, as shown in Fig. 2(A). The liquid mixing ratio is χ. Looking at this figure 2 (A) equivalently, as shown in figure 2 (B), it can be considered to be separated into the liquid FQ and the air bubble "F" above the liquid level FL. In this case, the gas The volume ratio occupied by can be expressed as χ when the total volume is 1.Here, the capacitance when the space between the electrodes is filled with vapor is y of CO1 liquid, and the electric coefficient is KFsFI.
When the dielectric constant of air is Ka, the capacitance CM detected between the electrodes is CM-χCo+(1-χ) CD (K
F /KG) = Co [((INF +Ko
) χ + Kp)/K G ]...(1
) can be expressed as Therefore, the gas-liquid mixture ratio calculation unit 9 inputting the capacitance a CM calculates χ= f, Kp (CM /CD) Kc ”t
/ (KF - KG) ... (2)
The gas-liquid mixture ratio χ can be calculated based on .

By the way, the electrode structure of the present invention is not limited to the structure shown in FIG. For example, it is also possible to construct the device as shown in FIG. 3, which shows another embodiment of the present invention.

That is, in FIG. 1, a pair of electrodes are arranged in a cylindrical shape, but in FIG.
) shows a case in which two pairs of plate-shaped electrodes are arranged so as to cross each other, but even in this case, the same effect as in FIG. 1 can be obtained by 1q. It goes without saying that the electrodes may have a plurality of configurations (for example, when the pipe diameter is increased, etc.).

・Effects of the Invention> As described above in detail with reference to the embodiments, the gas-liquid mixture ratio measuring device of the present invention comprises a capacitance measurement method that utilizes the dielectricity of a fluid using at least one pair of electrodes. According to the authors, since transmission is a phenomenon that occurs at the speed of light, it is possible to accurately measure the gas-liquid mixture ratio without being affected by the speed of the fluid.

In addition, since the capacitance of the entire fluid is measured, it is possible to measure the average difference (distribution) in the gas-liquid mixing ratio depending on the location within the pipe, so accurate gas-liquid mixing is possible without having to correct the distribution within the pipe. It is possible to obtain the effect of obtaining a ratio.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a gas-liquid mixture ratio measuring device showing a specific embodiment of the present invention, FIG. 2 is a diagram provided for the present invention, and FIG.
The figure shows another embodiment of the present invention, and FIG. 4 is a diagram illustrating the outline of a conventional gas-liquid mixture ratio measuring device. DESCRIPTION OF SYMBOLS 1... Pipe, 2... Strut, 3... Gas-liquid mixture ratio measuring section, 4... Gas-liquid mixing ratio calculating section, 5... Core, 6...
... Outer electrode, 7... Inner electrode, 8... Capacitance conversion section, 9... Gas-liquid mixture ratio calculation section.

Claims (1)

[Claims] A pipe through which a fluid containing a mixture of gas and liquid flows, at least a pair of electrodes installed in the pipe and configured to allow the fluid to pass through, and the pair of electrodes are connected to each other, and the detected value of the electrode is measured by capacitance. A gas-liquid mixing device comprising: a capacitance conversion section that converts the capacitance into a capacitance; and a gas-liquid mixture ratio calculation section that inputs the capacitance and calculates a gas-liquid mixture ratio of the fluid. Ratio measuring device.