JP3122982B2 - Flow measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate measuring device suitable for application to fluids such as muddy water in which a gas is mixed in a liquid.

[0002]

2. Description of the Related Art There are two types of fluid flowing in a pipe: a one-phase fluid containing only liquid, a so-called gas-liquid two-phase fluid in which gas and liquid are mixed, and a gas-solid-liquid three-phase fluid in which gas, solid and liquid are mixed. There are three types of fluids. Examples of the two-phase fluid in which a gas and a liquid are mixed include a fluid in which gas is easily generated, for example, a liquid such as sludge and sewage, and a liquid in which bubbles are generated in relation to temperature and pressure, such as boiling water. As a three-phase fluid,
A slurry fluid in which gas is easily generated can be used.

[0003] Sewage includes sewage transported by vacuum cars as a business. In this case, since the amount of the sewage pumped by the vacuum car is charged according to the amount, it is necessary to accurately measure the flow rate. However, when gas is mixed, the flow rate of only the liquid cannot be measured accurately, which causes measurement failure. Further, in the case of a slurry fluid containing a solid, any flow meter may not be used.

FIGS. 5A and 5B are schematic structural views showing a conventional flow measuring device. This flow measuring device is a gas G
Flows through the upper tube 1, the other flows through the lower tube 2, and an electromagnetic flowmeter 3 is connected in the middle of the lower tube 2 to measure the flow rate of the liquid L. The upper pipe 1 and the lower pipe 2 are connected to a buffer tank 4 containing a floating body 5. The floating body 5 closes the upstream opening 2a of the lower pipe 2 when the amount of the liquid L decreases, and prevents the liquid L from flowing through the electromagnetic flow meter 3 until a certain amount or more is accumulated. However, in the buffer tank 4 through which the filth 6 flows, they often adhere to the floating body 5 and the upstream opening 2a, so that even when the flow rate decreases, the floating body 5 completely closes the upstream opening 2a. And the liquid L mixed with gas could flow into the electromagnetic flowmeter 3 in some cases. As is well known, the flow rate of the electromagnetic flow meter 3 cannot be accurately measured when gas is mixed therein, which causes an error. In addition,
7 is a switching valve.

[0005]

As described above, the floating body 5 is accommodated in the buffer tank 4 and the gas G is supplied to the upper pipe 1.
In the conventional flow measuring device in which the liquid L is caused to flow through the lower pipe 2 and the flow rate is measured by the electromagnetic flowmeter 3, when the dirt 6 adheres to the floating body 5, even if the liquid L decreases, the floating body 5 cannot completely close the lower tube 2 and the liquid L mixed with the gas G flows,
There has been a problem that the flow rate of only the liquid L cannot be accurately measured, and a measurement error occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a flow rate capable of accurately measuring only a liquid even when the fluid becomes small. It is to provide a measuring device. Another object of the present invention is to provide a flow measuring device capable of accurately measuring the flow rates of a liquid and a gas.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a buffer tank having a fluid inlet at an upper part and a discharge port at a lower part; A partition that partitions the upstream chamber and a downstream chamber that communicates with the discharge port, and first and second communication holes that communicate the upstream chamber and the downstream chamber at the upper and lower portions of the partition plate. A second communication hole is positioned below the discharge port, and a flow meter for measuring a flow rate of the liquid passing through the second communication hole is provided. Further, the present invention provides a buffer tank provided with a fluid inlet at the top and a drain at the bottom, an upstream chamber communicating the interior of the buffer tank with the inlet, and a downstream chamber communicating with the outlet. A first and a second communication hole for communicating the upstream chamber and the downstream chamber with each other at an upper portion and a lower portion of the partition plate, and an electromagnetic flowmeter provided at the second communication hole. The side opening end is located above the flow meter main body. Further, the present invention is characterized in that the flow meter is an electromagnetic flow meter. Further, the present invention is characterized in that the flow meter is a differential pressure flow meter. Further, the present invention is characterized in that a flow meter for measuring a flow rate of the gas passing through the first communication hole is provided.

In the present invention, when the fluid is introduced into the upstream chamber from the inlet of the buffer tank, the gas and the liquid are separated. The gas flows through the first communication hole to the downstream chamber, and the liquid flows through the second communication hole, the flow rate of which is measured by the flow meter, to the downstream chamber. The liquid may be a solid-liquid two-phase fluid containing a solid. Examples of the flowmeter include a submerged electromagnetic flowmeter, a differential pressure flowmeter in which pressure is guided to a diaphragm by a pressure guiding tube, and a remote seal diaphragm type differential pressure flowmeter in which pressure is guided to a diaphragm by a capillary tube. Can be used. In the case of a gas-solid liquid three-phase fluid, in a differential pressure gauge using a pressure guiding tube, solids may be clogged in the pressure guiding tube. However, when a remote seal diaphragm type differential pressure flow meter is used, there is no concern. If the second communication hole is provided below the discharge port, when the fluid becomes gas only, the liquid remains in the bottom of the tank and does not flow to the discharge port. For this reason, the flow meter is submerged in the liquid, and the gas does not pass through, and the flow rate of the liquid alone can be measured. If a flow meter is provided on the first communication hole side, the gas flow rate can be measured.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. 1A and 1B are schematic configuration diagrams of a flow rate measuring device according to the present invention. In addition,
The same components as those described in the section of the related art are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
In the present embodiment, an example in which the present invention is applied to a low-viscosity liquid flow measurement device will be described. The flow measurement device 10 includes a pipe 11 (1
Buffer tank 4 connected in the middle of 1a, 11b)
It has. The buffer tank 4 has an upstream pipe 11
a to which the fluid inlet 12 is connected, and the downstream pipe 11 b
The inside is partitioned by a partition plate 14 into an upstream chamber 15 and a downstream chamber 16. The inlet 12 is provided in the upper part of the side wall of the buffer tank 4,
The outlet 13 is provided at the lower part of the side wall. Partition plate 14
Has first and second communication holes 17 and 18 spaced apart in the vertical direction, and the upstream chamber 1 is formed by these two communication holes.
5 and the downstream side chamber 16 communicate with each other. Also, the second
The communication hole 18 is provided so that its upper end is located below the lower end of the outlet 13, and a submerged electromagnetic flowmeter 3 immersed in a liquid is attached as a flowmeter. Although the buffer tank 4 is shown as a vertically long tank, it is not limited to this and may be a horizontally long tank.

The flow rate measuring device 10 having such a structure
When the fluid is introduced from the upstream pipe 11a to the buffer tank 4, the fluid is separated into a gas and a liquid in the upstream chamber 15. The gas flows through the first communication hole 17 to the downstream chamber 16, and the liquid passes through the electromagnetic flow meter 3 and flows into the downstream chamber 1.
The flow rate is measured by flowing to 6. When the viscosity of the liquid is close to that of water, the flow measuring device 10
The structure is such that the water flows out due to the water level H1 in the downstream chamber 16.
If the internal water level is higher than H2, it will flow out.

When the fluid becomes gas only, the liquid is transferred to the upstream chamber 15 and the downstream chamber 16 as shown in FIG.
Is kept at the bottom of the container, and is not discharged from the discharge port 13. Even in this state, the electromagnetic flow meter 3
Since is completely submerged in the liquid, no gas flows. Therefore, the flow rate of only the liquid can be measured, and no measurement error occurs due to the gas, and the output signal at the zero point can be prevented. Further, according to the flow rate measuring device 10, it is possible to measure the flow rate of only the gas. That is, the gas is discharged from the downstream pipe 11 b through the first communication hole 17-the downstream chamber 16-the discharge port 13. Therefore, a differential pressure flow meter 20 is provided as shown in FIG.
1 and P2 are led to the diaphragm 21 by the pressure guiding tubes 22A and 22B, and when the differential pressure ΔP is detected, the flow rate of the gas can be measured by the following equation.

[0012]

(Equation 1)

Here, W: flow rate, K: flow coefficient (determined by experiment), ΔP: differential pressure, γ: density. The first communication hole 17 functions as a throttle. As the aperture, an orifice, a nozzle, or the like can be used.

FIG. 2 is a schematic configuration diagram showing another embodiment of the present invention. In this embodiment, an example in which the present invention is applied to a high-viscosity gas-liquid two-phase flow rate measuring device will be described. As the flow meter, similarly to the differential pressure flow meter 20 shown in FIG. 1B, the flow meter includes pressure guiding tubes 25A and 25B and a diaphragm 26, and is upstream and downstream of the second communication hole 18 by the pressure guiding tubes 25A and 25B. A known differential pressure flow meter 2 for guiding the pressures P1 and P2 on the side to the diaphragm 26 and measuring the flow rate of the liquid by the differential pressure .DELTA.P.
7 is used. The second communication hole 18 functions as a throttle. Other configurations are the same as those of the above-described embodiment. Even in such a structure, the flow rate of the fluid can be accurately measured. If a flow meter is provided in the first communication hole 17 as in the above-described embodiment, the flow rate of the gas can be measured.

FIGS. 3 (a) and 3 (b) are a schematic configuration diagram and a sectional view showing still another embodiment of the present invention. In this embodiment, an example in which the present invention is applied to a high-viscosity gas-solid-liquid three-phase flow rate measuring device will be described. As flow meters, capillary tubes 30A and 30B, and liquid contact diaphragms 31A and
31B and a pressure receiving diaphragm 32, and the displacement of the liquid contacting diaphragms 31A and 31B is controlled by the capillary tube 30.
A well-known remote seal diaphragm type differential pressure flowmeter 35 for guiding the liquid flow to the pressure receiving diaphragm 32 by using the sealed liquid sealed in the A and 30B and measuring the flow rate of the liquid is used. In such a flow rate measurement device, even if a solid is contained in the liquid, there is no risk of clogging the capillary tubes 30A and 30B, and accurate measurement can be performed.

FIG. 4 is a schematic configuration diagram showing still another embodiment of the present invention. In this embodiment, an example in which the present invention is applied to a low-viscosity gas-liquid three-phase flow rate measuring device will be described. The buffer tank 4 is designed to be horizontally long in consideration of mounting on a vacuum tank. As the flow meter, a submerged electromagnetic flow meter 40 having an elbow 42 is used. The submerged electromagnetic flowmeter 40 is provided with a flowmeter body 4 immersed in a liquid.
1 and the elbow 42 provided at the downstream end of the flow meter main body 41. The elbow 42 is curved upward so that its tip is located above the flow meter main body 41. The discharge port 13 is provided at a position lower than the elbow 42. Also in such a structure, when the fluid becomes only gas, the flowmeter main body 41 is submerged in the liquid stored in the upstream chamber 15, so that the gas does not pass through the electromagnetic flowmeter 40, The occurrence of a measurement error can be prevented. Further, there is an advantage that the outlet 13 can be provided along the bottom of the buffer tank 4.

[0017]

As described above, the flow measuring device according to the present invention comprises a buffer tank provided with a fluid inlet at the upper part and a discharge port at the lower part, and the inside of the buffer tank as the inlet. A partition plate that partitions the upstream chamber into communication and a downstream chamber that communicates with the discharge port, and first and second communication holes that allow the upstream chamber and the downstream chamber to communicate with each other at upper and lower portions of the partition plate; Since the second communication hole is located below the discharge port and a flow meter for measuring the flow rate of the liquid passing through the second communication hole is provided, the liquid always exists below the discharge port of the tank and the flow meter is provided. Can be located in the liquid. Therefore, even when the fluid is only gas, the gas does not pass through the flow meter, and only the flow rate of the liquid can be accurately measured.

The present invention also provides a buffer tank provided with a fluid inlet at the top and a drain at the bottom,
A first partition for partitioning the inside of the buffer tank into an upstream chamber communicating with the introduction port and a downstream chamber communicating with the discharge port; and an upper and a lower portion of the partition plate for communicating the upstream chamber and the downstream chamber with each other. Since the second communication hole is provided, the electromagnetic flow meter is provided in the second communication hole, and the downstream open end is located above the flow meter main body, the flow rate of only the liquid is measured in the same manner as in the above invention. And the outlet can be provided at a position lower than the flow meter. Further, in the present invention, since the flow meter is provided in the first communication hole, the flow rate of the gas can be measured in addition to the flow rate of the liquid.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic configuration diagrams showing one embodiment of a flow rate measuring device according to the present invention.

FIG. 2 is a schematic configuration diagram showing another embodiment of the present invention.

FIGS. 3 (a) and 3 (b) are schematic structural views showing still another embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing still another embodiment of the present invention.

FIGS. 5A and 5B are schematic configuration diagrams showing a conventional example of a flow measurement device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Upper piping, 2 ... Lower piping, 3 ... Electromagnetic flowmeter, 4 ... Buffer tank, 5 ... Floating body, 10 ... Flow measurement device, 11
... Piping, 12 ... Inlet, 13 ... Outlet, 14 ... Partition plate,
Reference numeral 15: upstream chamber, 16: downstream chamber, 17: first communication hole, 18: second communication hole, 20: differential pressure flow meter, 21: diaphragm, 27, 35: differential pressure flow meter, 40: electromagnetic flow rate 42 in total, elbow.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01F 15/08 G01F 1/00 G01F 1/42 G01F 1/58

Claims (5)

(57) [Claims] 1. A buffer tank provided with a fluid inlet at an upper part and a discharge port at a lower part, and an inside of the buffer tank is connected to an upstream chamber communicating with the inlet and a downstream chamber communicating with the outlet. A partition plate, and first and second communication holes for communicating the upstream chamber and the downstream chamber are provided in upper and lower portions of the partition plate, and the second communication hole is located below the discharge port. And a flow meter for measuring a flow rate of the liquid passing through the second communication hole. 2. A buffer tank provided with a fluid inlet at an upper part and a discharge port at a lower part, and an inside of the buffer tank with an upstream chamber communicating with the inlet and a downstream chamber communicating with the outlet. A first and second communication holes for communicating the upstream chamber and the downstream chamber with each other at an upper portion and a lower portion of the partition plate, and an electromagnetic flowmeter provided at the second communication hole. A flow measuring device characterized in that an open end is located above a flow meter main body. 3. The flow measuring device according to claim 1, wherein
A flow measuring device, wherein the flow meter is an electromagnetic flow meter. 4. The flow measuring device according to claim 1, wherein
A flow measuring device, wherein the flow meter is a differential pressure flow meter. 5. The flow rate measuring device according to claim 1, further comprising a flow meter for measuring a flow rate of the gas passing through the first communication hole.