JPS5936211B2 - Specific gravity and flow rate measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for measuring the specific gravity and flow rate of liquids such as turbid water and muddy water.

When treating turbid water or muddy water, it is necessary to know the specific gravity and flow rate of the raw water to be treated, that is, turbid water or muddy water.
The following devices are available to keep the specific gravity and flow rate constant. That is, devices for measuring specific gravity include a float type hydrometer, a differential pressure type hydrometer, a gamma ray densitometer, and the like. A float-type hydrometer measures the specific gravity of a liquid from the displacement of a float, a differential-pressure hydrometer measures the specific gravity from the pressure difference between liquids at a certain height, and a gamma-ray densitometer measures the absorption power of gamma-rays. This is an application of the fact that the density (specific gravity) of the liquid changes depending on the density (specific gravity) of the liquid, but in a differential pressure type hydrometer it is necessary to increase the liquid property to create a pressure difference, and in a gamma ray densitometer it is necessary to increase the liquid property. Since radiation is used, the device is complicated and expensive, so it is desirable to use a float type hydrometer. In addition, devices for measuring flow rate include weir type flowmeters, electromagnetic flowmeters, and the like. What is a weir-type flowmeter? When a weir is installed in an open channel, the liquid level changes depending on the flow rate, so the flow rate is measured by detecting the height of the liquid level with a bloat, etc., and an electromagnetic flowmeter. A flowmeter is a device that flows a conductive liquid into a pipe, applies a magnetic field to the conductive fluid, and measures the electromotive force generated when the conductive fluid flows, but electromagnetic flowmeters are complicated and expensive. , it is desirable to use a weir type flow meter. Conventionally, float-type hydrometers use a single float, and in this case, it is difficult to accurately measure the specific gravity when the liquid level changes, especially when the liquid is flowing. Specific gravity cannot be measured accurately due to the effects of viscosity and viscosity.

Furthermore, in a weir-type flowmeter that detects the liquid level height using a float, the flow rate cannot be measured because the liquid level height cannot be measured when the specific gravity changes.
Furthermore, there is no device that can measure both specific gravity and flow rate with one device. This invention was made in order to solve the above-mentioned problems, and aims to provide a specific gravity and flow rate measuring device that can measure the specific gravity and flow rate of a liquid whose specific gravity and flow rate both change. .

In order to achieve this objective, the present invention provides a weir plate in an open channel, and provides two floats supported vertically movably on the upstream side of the weir plate and having different weights, and A height detection device is installed to detect the height.
The specific gravity of the liquid in the open channel is determined from the difference in height between the two floats, and the flow rate of the liquid is determined from the specific gravity and the height of one of the two floats. FIG. 1 is a perspective view showing a specific gravity and flow rate FAl stagnation device according to the present invention, and FIG. 2 is a side sectional view thereof.

In the figure, 1 is an open channel, 2 is a liquid to be measured flowing through the open channel 1, 3 is a weir plate provided in the open channel 1, 4 is a bracket attached to the open channel 1, and the bracket 4 is the upstream side of the weir plate 3. It is located on the side. 5 and 6 are parallelogram links attached to the bracket 4, T and 8 are floats attached to the parallelogram links 5 and 6, respectively, and the float T
, 8 are vertically movably supported by parallelogram links 5, 6, and the floats T, 8 have the same shape, but the weights of the floats T, 8 are different.

9 and 10 are potentiometers for detecting the heights of floats T and 8, respectively. Potentiometers 9 and 10 detect changes in the heights of floats T and 8 as changes in rotation angle, and convert them into electrical quantities. Convert.

Next, the principle of measuring the specific gravity of the liquid 2 from the heights of the floats 7 and 8 will be explained with reference to FIG.

The specific gravity of liquid 2 is γ, and the weights of floats T and 8 are W.
a, Wb) The volume below the liquid surface of liquid 2 is Va, Vb, liquid 2
When the i constant cross-sectional area of the liquid surface portion of S1 is the length of the liquid 2 above the liquid surface as A and b, the following relationship holds true. At this time, the height Ha from the bottom of the open channel 1 to the top of the float T,8 is
If the difference in hb, that is, the difference in lengths A and b, is δ, then (1)
From equation (3), δ is expressed by the following equation.

When specific gravity γ is determined from equation (4), it becomes as shown in the following equation.

In equation (5), the specific gravity γ of the liquid 2 can be determined by determining a constant difference δ between the cross-sectional areas S1 and the heavy electric currents Wa and Wb.
Next, the specific gravity γ obtained by the two floats 1 and 8 and one of the two floats T and 8, for example, the float T
The principle of determining the flow rate a of the liquid 2 from the height h 2 will be explained with reference to FIG.

In the case of a triangular weir, if the flow coefficient is c, the triangular weir angle is θ, the gravitational acceleration is g, and the liquid level height from the lowest point of the notch 3a of the triangular weir is H, then the flow rate Q of liquid 2 is calculated by the following formula. It can be found by Here, since the flow coefficient C1, the triangular weir angle θ, and the gravitational acceleration g are constant, the flow rate Q can be determined by measuring the liquid level height H.

By the way, the height from the reference plane, for example, the bottom of the open channel 1 to the lowest point of the notch 3a of the triangular weir, is H. , the total volume of the float T is V. Assuming that a, the following relationship holds true. Then, when the height H is determined from equations (1), (η, and (8)), the following equation is obtained.In equation (9), the capacitance V.

at cross-sectional area S1 weight Wa, height H. is constant, and the specific gravity γ can be determined from the difference in height between the two floats T and 8, so the height Ha of the float 7 is lost! If it stagnates, the height H can be determined, and therefore the flow rate Q can be determined using equation (6). FIG. 5 is a block diagram showing the arithmetic unit portion of the specific gravity and flow rate measuring device according to the present invention.

In the figure, 11 is an arithmetic unit, and 12 and 13 are a flow rate indicator and a specific gravity indicator, respectively. In this device, the heights Ha and hb from the bottom of the open channel 1 to the tops of the floats T and 8 are measured by the potentiometers 9 and 10, and the calculation circuit Ila calculates δ=Ha-Hb. , the arithmetic circuit 11b performs the calculation of equation (5) and indicates the value of specific gravity γ on the specific gravity indicator 13. on the other hand. The arithmetic circuit 11c calculates equation (9), and the arithmetic circuit Ild
The value of the flow rate Q is indicated on the flow rate indicator 12 by calculating the equation 6). Note that the specific gravity γ may be determined as follows.

That is, the known specific gravity γ. Float in a liquid such as water T
, 8 is floating, the difference in height of float T, 8 is δ. Then, from equation (4), the height difference δ. is expressed by the following equation. Next, (4), δ/δo is calculated from the Q test as follows.

Then, the specific gravity γ can be determined using the following formula.

Therefore, the specific gravity γ. The height difference δ when . By measuring in advance, the specific gravity γ can be determined. Alternatively, the flow rate Q may be determined as follows.

As shown in Figure 4A, the liquid level is H. In other words, the height of the float 7 when it is placed at the lower end of the weir notch and floated in a liquid with a flow rate Q of zero and a known specific gravity γ0 is HaO,
In the same case, the length of the float T above the liquid level is A. , when the volume of the float T below the liquid surface is VaO, the following relationship holds true. Here, if a-AO=Δa, the height difference Δa is expressed as follows from the equation a′,C[°.

Then, when the height H is determined from the equation (η, a'3), the following equation is obtained. Therefore, the liquid level is at the lower end of the weir notch, the flow rate is zero, and the specific gravity is γ.

If the height HaO at the time is measured in advance, the height H can be determined. Then, by substituting this height H into equation 6), the flow rate Q can be determined. In the above-described embodiment, the floats T and 8 have the same shape, but the floats T and 8 may have different shapes.

The constant cross-sectional areas of the liquid surface portions of the two floats are Sa and Sb, respectively, and the total volume is V. Let a, VOb be (
The formula corresponding to formula 5), that is, the formula for determining specific gravity γ, is as follows. In addition, in the above embodiment, the float T, 8
Parallelogram links 5 and 6 are used to support the
However, other means may be used to support the floats T and 8 in a vertically movable manner. Furthermore, in the above embodiment, 2
Although potentiometers 9 and 10 are used as height detection devices for detecting the heights of the two floats T and 8, other means may be used to detect the heights of the floats T and 8. Further, the calculation may be performed by a computer. As explained above, in the specific gravity and flow rate measuring device according to the present invention, even if both the specific gravity and flow rate of the liquid change, the specific gravity and flow rate of the liquid can be measured.

In other words, since two floats are used, the specific gravity can be determined even if the liquid level changes, and even if the specific gravity changes, the specific gravity can be measured using two floats, so the flow rate can be measured. Furthermore, if specific gravity is measured using two floats of the same shape, the effects of fluid flow and viscosity will act on the two floats in almost the same way, so the error in measurement due to these effects will be reduced, and the specific gravity will be Furthermore, it can be measured accurately. As described above, the effects of this invention are remarkable.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the specific gravity and flow rate FAl stagnation device according to the present invention, Fig. 2 is a side sectional view thereof, Fig. 3 is an explanatory diagram of the principle of measuring specific gravity, and Fig. 4 is the principle of measuring flow rate. In the explanatory diagram, A has a specific gravity of γ. , when the flow rate is zero, the specific gravity at the mouth is γ, and when the flow rate is zero, C shows the case where the specific gravity is γ and the flow rate is Q. FIG. 5 is a block diagram showing the arithmetic unit portion of the specific gravity and flow rate measuring device according to the present invention. 1...Open channel, 2...
...Liquid to be measured, 3...Weir plate, 5, 6...
...parallelogram link, T, 8... float, 9, 10 potentiometer.

Claims (1)

[Claims] 1 Equipped with a weir plate installed in an open channel, two floats supported vertically movably on the upstream side of the weir plate and having different weights, and a height detection device that detects the heights of the two floats. The specific gravity is characterized in that the specific gravity of the liquid in the open channel is determined from the difference in height between the two floats, and the flow rate of the liquid is determined from the specific gravity and the height of one of the two floats. and flow measurement equipment.