JP7389408B2 - fluid mixing device - Google Patents

Description

The present invention relates to a fluid mixing device that adds and mixes a liquid fluid to a gaseous fluid flowing through a main stream pipe.

When liquefied natural gas (hereinafter referred to as "LNG") is vaporized and supplied as city gas, the amount of heat is adjusted. In recent years, imports of LNG with a high methane content, such as shale gas, have increased, and the heat is often increased for use as city gas. The amount of heat is adjusted by mixing natural gas (hereinafter referred to as "NG") obtained by vaporizing LNG with a heat agent for adjusting the amount of heat (for example, LPG).

When mixing heat preparation with NG in this way, the flow rate of NG varies depending on the demand for city gas, so it is necessary to be able to adjust the amount of heat at a constant level even if the NG flow rate varies.
As an example of such a device, there is a "fluid mixing device" disclosed in Patent Document 1.
What is disclosed in Patent Document 1 is "a fluid mixing device that mixes a first fluid flowing through a main stream pipe by supplying a second fluid midway through the main stream pipe, and which includes a first fluid flowing through the main stream pipe that is branched from the main stream pipe. a branch pipe provided with a small diameter portion whose flow passage cross section is smaller than that of the main flow pipe, and whose outlet side is connected to the downstream side of the branch position of the branch flow channel in the main flow channel; a second fluid supply port provided at or near the small diameter portion to supply the second fluid; and a second fluid supply port provided downstream from the branch portion of the branch pipe in the main flow pipe and upstream from the outlet portion of the branch pipe. and a flow rate adjustment valve that adjusts the flow rate flowing through the main flow pipe.'' (see claim 4 of Patent Document 1).

In the fluid mixing device of Patent Document 1, "a branch channel having a small diameter portion with a cross section smaller than that of the main channel is provided branching from the main channel, and the outlet side of the branch channel is connected to the main channel. A supply section for the second fluid is provided at or near the small diameter section of the branch channel, and the first fluid flows through the small diameter section of the branch channel by adjusting the flow rate of the main channel. Since the flow rate of the fluid is maintained at the flow rate necessary for mixing the first fluid and the second fluid, it is possible to reliably obtain a high mixing effect over a wide flow rate range.'' (See [0020] of Patent Document 1).

Japanese Patent Application Publication No. 2011-56400

In the fluid mixing device of Patent Document 1, the branch flow path is branched from the main flow path and reintroduced from the outside of the main flow path, so a branch pipe is required to provide the branch flow path, which increases the device size accordingly. This poses a problem in that the installation area in an actual plant increases.
Further, since the branch pipes forming the branch flow paths are routed outside the main flow path, there is a problem in that pressure loss increases and the cost of NG transportation power increases accordingly.

The present invention has been made to solve these problems, and it is possible to suppress pressure loss and maintain a high mixing effect without increasing the size of the device, even if there is a fluctuation in the flow rate of the gaseous fluid flowing through the main pipe. The present invention aims to provide a fluid mixing device that can be obtained.

(1) The fluid mixing device according to the present invention is a fluid mixing device that mixes a gaseous first fluid flowing through a main stream pipe by supplying a liquid second fluid to the gaseous first fluid flowing through the main stream pipe. hand,
A sub-flow pipe disposed within the main-stream pipe and having a smaller diameter than the main-stream pipe, a second fluid supply pipe that supplies the second fluid to the sub-flow pipe, and a flow passage cross-sectional area of the main flow passage of the main-stream pipe. The present invention is characterized by comprising a flow passage cross-sectional area adjustment valve that adjusts the flow rate of the first fluid flowing into the secondary flow pipe by adjusting the flow rate of the first fluid flowing into the subflow pipe.

(2) Furthermore, in the item described in (1) above, a venturi pipe is provided in the main flow channel, and the outlet side of the side flow pipe is disposed at the throat of the venturi pipe or its upstream side. It is something.

(3) Furthermore, in the item described in (1) or (2) above, an actuator for operating the flow path cross-sectional area adjustment valve, and a flow path upstream and/or downstream of the flow path cross-sectional area adjustment valve. The present invention is characterized by comprising a detection device that detects fluid pressure, and a control section that controls the actuator based on a detection signal from the detection device.

(4) Furthermore, in the item described in (1) or (2) above, an actuator that operates the flow path cross-sectional area adjustment valve, and a detection device that detects the flow rate or flow velocity of the fluid flowing through the side flow pipe; The present invention is characterized by comprising a control section that controls the actuator based on a detection signal from the detection device.

(5) Furthermore, in the device described in (1) or (2) above, an actuator that operates the flow path cross-sectional area adjustment valve and a flow rate of the fluid flowing upstream of the flow path cross-sectional area adjustment valve are detected. a second flow rate detection device that detects the flow rate of fluid flowing through the main flow path in the gap between the side flow pipe and the main flow pipe; and the first flow rate detection device and the second flow rate detection device. The present invention is characterized by comprising a control section that controls the actuator based on a detection signal.

(6) Furthermore, in the device described in any one of (1) to (5) above, the flow passage cross-sectional area adjusting valve is configured to be able to close the main flow passage.

(7) Furthermore, in the item described in any one of (1) to (6) above, the flow passage cross-sectional area adjustment valve is a shutter valve whose plate-shaped body is movable in a direction crossing the main flow passage. This is a characteristic feature.

(8) Also, in any one of (1) to (6) above, the flow passage cross-sectional area adjusting valve is a butterfly valve that rotates a plate-shaped valve body around an axis perpendicular to the main flow passage. It is characterized by:

(9) Furthermore, in the apparatus described in (8) above, the butterfly valve is characterized in that in a closed state, the butterfly valve has an opening at a portion corresponding to the inlet of the side flow pipe.

(10) Furthermore, in the apparatus described in (9) above, the inlet of the side flow pipe is arranged near the wall of the main flow pipe.

(11) Also, in the item described in (9) above, the inlet of the side flow pipe is arranged in the center of the main flow path, and the butterfly valve is provided on the pipe wall near the inlet of the side flow pipe. The present invention is characterized in that a baffle plate is provided that closes a gap between the butterfly valve and the wall of the side flow pipe when the butterfly valve is closed.

(12) Furthermore, in the apparatus described in (8) above, the butterfly valve is constituted by two plate-shaped valve bodies sandwiching the side flow pipe.

(13) Furthermore, in the item described in (12) above, the inlet of the secondary flow pipe has a diameter-enlarging portion that expands in diameter in a flat shape, and the side surface of the upstream end of the diameter-enlarging portion is connected to the main flow pipe. The butterfly valve is in contact with a wall, and the two valve bodies of the butterfly valve are provided so as to sandwich the enlarged diameter portion.

In the present invention, there is provided a secondary flow pipe disposed within the main flow pipe and having a smaller diameter than the main flow pipe, a second fluid supply pipe supplying a liquid second fluid to the secondary flow pipe, and a main flow channel of the main flow pipe. The flow rate of the gaseous fluid flowing through the main flow pipe is increased by providing a flow passage cross-sectional area adjustment valve that adjusts the flow rate of the gaseous first fluid flowing into the secondary flow pipe by adjusting the flow passage cross-sectional area of the main flow pipe. A high mixing effect can be obtained even when there are fluctuations, and there is no need to install a branch pipe as in conventional examples, saving space. There is no large pressure loss as with pipes, and increases in gas transportation power costs can be suppressed.

1 is a plan cross-sectional view of the fluid mixing device according to Embodiment 1. FIG. FIG. 2 is an enlarged perspective view (a) of a part of the fluid mixing device shown in FIG. 1 and an explanatory view (b) of a shutter valve. 2 is an explanatory diagram of the operation of the shutter valve shown in FIG. 1. FIG. FIG. 2 is an explanatory diagram of another aspect of the fluid mixing device shown in FIG. 1 (Part 1). FIG. 2 is an explanatory diagram of another aspect of the fluid mixing device shown in FIG. 1 (Part 2). FIG. 3 is an explanatory diagram of another aspect of the fluid mixing device shown in FIG. 1 (No. 3). FIG. 4 is an explanatory diagram of another aspect of the fluid mixing device shown in FIG. 1 (No. 4). FIG. 5 is an explanatory diagram of another aspect of the fluid mixing device shown in FIG. 1 (No. 5). FIG. 3 is a plan cross-sectional view of a fluid mixing device according to a second embodiment. 10 is an explanatory diagram of the operation of the fluid mixing device shown in FIG. 9. FIG. FIG. 7 is a plan cross-sectional view of another aspect of the fluid mixing device according to the second embodiment (part 1). 12 is an explanatory diagram of main parts of the fluid mixing device shown in FIG. 11. FIG. 12 is an explanatory diagram of the operation of the fluid mixing device shown in FIG. 11. FIG. FIG. 7 is a plan cross-sectional view of another aspect of the fluid mixing device according to the second embodiment (part 2). 15 is an explanatory diagram of main parts of the fluid mixing device shown in FIG. 14. FIG. 15 is an explanatory diagram of the operation of the fluid mixing device shown in FIG. 14. FIG. FIG. 7 is a plan cross-sectional view of another aspect of the fluid mixing device according to the second embodiment (Part 3). FIG. 18 is an enlarged perspective view of a part of FIG. 17; 18 is an explanatory diagram of the operation of the fluid mixing device shown in FIG. 17. FIG.

[Embodiment 1]
As shown in FIG. 1, a fluid mixing device 1 according to an embodiment of the present invention adds a liquid second fluid (additive) to a gaseous first fluid flowing through a main stream pipe 3. A secondary flow pipe 5 having a diameter smaller than that of the main flow pipe 3 disposed inside the main flow pipe 3 and a second flow pipe 5 that supplies a second fluid to the secondary flow pipe 5 are used to mix both fluids by supplying a second fluid to the main flow pipe 3. A shutter valve as a flow passage cross-sectional area adjustment valve that adjusts the flow rate of the first fluid flowing into the sub-flow pipe 5 by adjusting the flow passage cross-sectional area of the fluid supply pipe 7 and the main flow passages 8, 8a of the main flow pipe 3. 9.
In the first embodiment, a Venturi tube 11 is installed in the main flow pipe 3 to form a Venturi type mixing device.
Note that the fluid mixing device 1 according to the present embodiment is used, for example, when producing city gas by adding LPG as a second fluid to NG obtained by vaporizing LNG as a first fluid to increase the heat. It is.
Each configuration will be explained in detail below.

<Main pipe>
The main flow pipe 3 is a pipe through which a gaseous first fluid (for example, NG) flows. The shape of the main flow pipe 3 is not particularly limited, and in this embodiment, the cross section perpendicular to the axial direction is rectangular as shown in FIGS. 2 and 3, but the cross section perpendicular to the axial direction may be circular. good.
The main flow path of the present invention is a flow path formed by the main flow pipe 3, and in the region where the side flow pipe 5 is arranged, the flow path sandwiched between the main flow pipe 3 and the side flow pipe 5 becomes the main flow path. . Therefore, in this embodiment, the main flow path sandwiched between the main flow pipe 3 and the side flow pipe 5 is referred to as a gap main flow path 8a, and the other main flow paths are referred to as a main flow path 8.

<Side flow pipe>
The side flow pipe 5 is disposed within the main flow pipe 3 and has a smaller diameter than the main flow pipe 3.
The side flow pipe 5 is disposed within the main flow pipe 3 by a stay or the like (not shown), but is preferably arranged parallel to the main flow pipe as shown in FIG. 1.
The secondary flow pipe 5 has a smaller diameter than the main flow pipe 3, and its cross-sectional area is smaller than that of the main flow pipe 3. Therefore, when the flow rate of NG flowing through the main flow channel 8 is constant, the flow rate of NG flowing through the gap main flow channel 8a is relatively By decreasing the flow rate of NG flowing through the side flow pipe 5 to increase the flow rate of NG flowing through the side flow pipe 5, the flow rate of NG flowing through the side flow pipe 5 becomes faster than the flow speed of the main flow path 8. Therefore, atomization of the liquid second fluid (for example, LPG) supplied to the side flow pipe 5 via the second fluid supply pipe 7 is promoted.

<Second fluid supply pipe>
The second fluid supply pipe 7 is a pipe that supplies the second fluid to the side flow pipe 5. The liquid second fluid supplied from the second fluid supply pipe 7 is atomized by the gas flow of the first fluid flowing through the side flow pipe 5 and mixed with the first fluid.
As shown in FIG. 1, the second fluid outlet part 7a of the second fluid supply pipe 7 is provided on the pipe wall of the side flow pipe 5, and is connected to the pipe axis of the side flow pipe 5 and the outlet of the second fluid supply pipe 7. The tube axes of the portion 7a are orthogonal to each other.
However, the shape of the outlet portion 7a of the second fluid supply tube 7 is not limited to that shown in FIG. 1, and the tip portion may be bent to be parallel to the tube axis of the side flow tube 5.

<Shutter valve>
The shutter valve 9 is one aspect of the flow passage cross-sectional area adjustment valve of the present invention, and adjusts the flow passage cross-sectional area of the gap main flow passage 8a of the main flow pipe 3 to adjust the flow rate of the first fluid flowing into the subflow pipe 5. This is a valve that adjusts the
As shown in FIG. 1, FIG. 2, and FIG. The body 13 is configured to be movable up and down in the figure with the side flow pipe 5 in between.
When the shutter valve 9 is fully closed, as shown in FIGS. 1 and 2, the main gap passage 8a is completely closed, and all of the first fluid flowing from the upstream side of the secondary flow pipe 5 flows into the secondary flow pipe. It will pass through 5.

On the other hand, when the shutter valve 9 is fully opened, the main gap passage 8a is fully opened, as shown in FIG. It passes through both the gap main channel 8a and the inside of the side flow pipe 5.
Then, by adjusting the opening degree of the shutter valve 9, the flow rate of the first fluid passing through the gap main channel 8a can be adjusted, thereby adjusting the flow rate of the first fluid passing through the subflow pipe 5. That is, if the total flow rate of the first fluid is the same, reducing the opening degree of the shutter valve 9 will relatively increase the flow rate of the first fluid flowing through the side flow pipe 5, and conversely, the opening degree of the shutter valve 9 will decrease. If is increased, the flow rate of the first fluid flowing through the side flow pipe 5 will be relatively reduced.

Conversely, when the flow rate of the first fluid changes, by adjusting the opening degree of the shutter valve 9, the flow rate of the first fluid flowing through the side flow pipe 5 can be made constant. That is, when the total flow rate of the first fluid decreases, the opening degree of the shutter valve 9 is reduced to relatively increase the flow rate of the first fluid flowing through the side flow pipe 5. When the total flow rate of the first fluid increases, the opening degree of the shutter valve 9 is increased to increase the flow rate of the first fluid flowing through the secondary flow pipe 5. By relatively decreasing , the flow rate of the first fluid flowing through the side flow pipe 5 can be made the same as before the change in the total flow rate.

The reason why this is done is to keep the flow rate of the first fluid passing through the side flow pipe 5 constant to keep the flow rate of the first fluid flowing through the side flow pipe 5 constant, as disclosed in Patent Document 1. This is to ensure that the liquid second fluid supplied to the side flow pipe 5 can be atomized even if there is a change in the flow rate of the first fluid.

The shutter valve 9 may be operated manually, but as shown in FIG. , an actuator 17 that operates the shutter valve 9, and a control section 19 that inputs a detection signal from the pressure detection device 15 to control the actuator 17, so that automatic control may be performed.
In this case, the opening degree of the shutter valve 9 is adjusted so that the differential pressure between the primary pressure and the secondary pressure detected by the pressure detection device 15 becomes a predetermined value.

<Operation explanation>
The operation of the present embodiment configured as described above will be explained using an example in which the shutter valve 9 is automatically controlled. Note that the first fluid is NG, the second fluid is LPG, and the mixed fluid is city gas.
The NG flow rate varies depending on the demand for city gas, but when the NG flow rate is large, the shutter valve 9 is in an open state as shown in FIG. 3.

The NG supplied from the upstream side flows through the gap main channel 8a inside the side flow pipe 5 and outside the side flow pipe 5 when passing through the side flow pipe 5. LPG is supplied to the side flow pipe 5 from the second fluid supply pipe 7, and the LPG is atomized and mixed by the NG gas flow flowing through the side flow pipe 5, and then flows into the throat 11a of the Venturi pipe 11. do.
On the other hand, NG flowing through the gap main channel 8a also flows into the throat portion 11a, and mixing of LPG is promoted in the throat portion 11a.

The flow rate of NG increases or decreases depending on the demand for city gas. For example, when the demand for city gas decreases and the flow rate of NG flowing through the main channel 8 decreases, the flow rate of NG flowing through the side flow pipe 5 decreases below a predetermined value, and the flow velocity within the side flow pipe 5 decreases, so that LPG There is a concern that the atomization and mixing of the particles may become insufficient.
In this case, the pressure loss of the NG flowing through the main channel 8 is reduced, and the differential pressure between the primary pressure and the secondary pressure detected by the pressure detection device 15 is reduced. Therefore, when the pressure difference between the primary pressure and the secondary pressure detected by the pressure detection device 15 becomes lower than a predetermined value A, the shutter valve 9 is moved in the closing direction to reduce the flow passage cross-sectional area of the gap main flow passage 8a. The flow rate of NG flowing through the side flow pipe 5 is maintained at a predetermined value.
By maintaining the flow rate of NG flowing through the side flow pipe 5 at a predetermined value or higher, the flow velocity in the side flow pipe 5 is maintained, and the LPG atomization/mixing effect can be ensured.

Conversely, when the demand for city gas increases, the flow rate of NG flowing through the main flow path 8 increases, and the flow rate of NG flowing through the side flow pipe 5 increases more than a predetermined amount, the pressure loss increases, which is detected by the pressure detection device 15. The differential pressure between the primary and secondary pressures increases.
Therefore, when the pressure difference between the primary pressure and the secondary pressure detected by the pressure detection device 15 becomes higher than the predetermined value B, the opening degree of the shutter valve 9 is increased to increase the amount flowing through the gap main flow path 8a, and the secondary pressure is increased. The NG flow rate flowing through the flow tube 5 is reduced. Here, there is a relationship of predetermined value B≧predetermined value A.
By setting the differential pressure between the primary pressure and the secondary pressure detected by the pressure detection device 15 of NG flowing through the main flow pipe 3 to a predetermined value A or more and below B, the flow velocity in the side flow pipe 5 is maintained within a predetermined range. can be sufficiently atomized and mixed.

As described above, according to the present embodiment, even if the flow rate flowing through the main channel 8 changes greatly, the NG flow rate in the side flow pipe 5 to which LPG is supplied can be maintained at a predetermined flow rate, and the LPG flow rate can be maintained at a predetermined flow rate. Atomization and mixing effects can be obtained.
Moreover, since the side flow pipe 5 is arranged inside the main flow pipe 3, unlike the conventional example, there is no need to provide a branch pipe, which saves space. There is no need to route the pipe around the pipe, and there is no large pressure loss that occurs with branch pipes, and an increase in fluid transport power costs can be suppressed.

In the case of automatic control of the shutter valve 9, if the primary pressure of the system is constant, a pressure detection device 15 is provided downstream of the shutter valve 9, as shown in FIG. The next pressure may be detected and the actuator 17 may be controlled based on this pressure. In this case, when the flow rate of NG flowing through the main flow path 8 decreases, the pressure loss decreases and the secondary pressure detected by the pressure detection device 15 increases. By reducing the cross-sectional area of the passage, the flow rate of NG flowing through the side flow pipe 5 is maintained at a predetermined value. Conversely, when the flow rate of NG flowing through the main flow path 8 increases, the pressure loss increases and the secondary pressure detected by the pressure detection device 15 decreases. The amount of NG flowing through the side flow pipe 5 is increased, and the flow rate of NG flowing through the side flow pipe 5 is decreased.
Furthermore, when the secondary pressure of the system is constant, as shown in FIG. Alternatively, the actuator 17 may be controlled by the actuator 17. In this case, when the flow rate of NG flowing through the main flow path 8 decreases, the pressure loss decreases and the primary pressure detected by the pressure detection device 15 decreases, so the shutter valve 9 is moved in the closing direction and the gap main flow path 8a is By reducing the cross-sectional area, the flow rate of NG flowing through the side flow pipe 5 is maintained at a predetermined value. Conversely, when the flow rate of NG flowing through the main flow path 8 increases, the pressure loss increases and the primary pressure detected by the pressure detection device 15 increases. The amount of NG flowing through the side flow pipe 5 is increased, and the flow rate of NG flowing through the side flow pipe 5 is decreased.

Further, instead of the pressure detection device 15, a flow rate detection device 16 for detecting the flow rate may be provided, and the actuator 17 may be operated based on a detection signal from the flow rate detection device 16. In this case, a flow rate detection device 16 is provided to detect the flow rate of the fluid flowing through the side flow pipe 5 (see FIG. 7), and the actuator 17 is operated to maintain the flow rate at a constant value.

Furthermore, instead of the flow rate detection device 16 that detects the flow rate, a flow rate detection device that detects the flow velocity may be provided. In this case, the flow rate detection device is provided at the same position as the flow rate detection device 16 shown in FIG. The actuator 17 may be operated to maintain the flow velocity at a constant value based on the detection signal of the flow velocity detection device.

Furthermore, as shown in FIG. 8, the flow rate detection device 16 is provided in both the main flow path 8 on the upstream side of the shutter valve 9 and the gap main flow path 8a on the downstream side, and these two flow rate detection devices 16 (in accordance with the present invention) are provided. The actuator 17 may be controlled based on detection signals from the first flow rate detection device and the second flow rate detection device so that the difference in flow rate between the primary side and the secondary side becomes constant.

[Embodiment 2]
In the first embodiment, the shutter valve 9 is used as the flow passage cross-sectional area adjustment valve, but the flow passage cross-sectional area adjustment valve of the present invention is not limited to this. It may also be a valve.
A fluid mixing device 20 using a butterfly valve as a flow path cross-sectional area adjustment valve will be described based on FIGS. 9 and 10. FIG. FIG. 9(a) is a plan cross-sectional view of the fluid mixing device 20, and FIG. 9(b) shows the butterfly valve. Note that in FIGS. 9 and 10, the same parts as in FIG. 1 are given the same reference numerals.

The butterfly valve 21 of the present embodiment includes a valve body 23 made of a circular plate, a rotation shaft 25 for rotating the valve body 23, and an operation part 27 for operating the rotation shaft 25. A circular opening 23a is provided at a position biased to .
The opening 23a forms a passage through which the first fluid passes toward the side flow pipe 5 when the gap main passage 8a is closed by the valve body 23.
As shown in FIGS. 9 and 10, the upstream end of the side flow pipe 5 is bent toward the wall of the main flow pipe 3, and the upstream end is positioned at the opening 23a of the valve body 23. It has become. The upstream end of the side flow pipe 5 is bent toward the pipe wall side of the main flow pipe 3 in order to prevent the valve body 23 from interfering with the side flow pipe 5 when rotating the valve body 23. It is.

In the butterfly valve 21 configured as described above, in the closed state, as shown in FIG. It's communicating. In this state, all the first fluid flows through the side flow pipe 5.
By operating the operation part 27 and rotating the rotating shaft 25 in the direction shown by the arrow in FIG. 9, a gap is formed between the valve body 23 and the pipe wall of the main pipe 3, as shown in FIG. Ru. In this state, the first fluid can flow through both the gap main channel 8a and the side flow pipe 5.

In the example shown in FIGS. 9 and 10, the upstream end of the side flow pipe 5 is bent toward the pipe wall side of the main flow pipe 3 to avoid interference with the valve body 23. To achieve this, as shown in FIGS. 11 to 13, the side flow pipe 5 may be a straight pipe, and the opening 23a provided in the valve body 23 may be formed into an elliptical shape.
In this case, even when the butterfly valve 21 is fully closed, a gap 29 is formed in the shaded area in FIG. 12, and it is not possible for all the first fluid to pass through the side flow pipe 5. However, the side flow pipe 5 can be a straight pipe, and the structure is simple.

However, in order to prevent the formation of a gap 29 as shown in FIG. 12 when the butterfly valve 21 is closed, a gap 29 is formed at the upstream end of the side flow pipe 5 as shown in FIGS. 14 to 16. A baffle plate 31 may be provided to cover the. In this way, as shown in FIG. 15, no gap 29 is formed when the butterfly valve 21 is closed, and all the first fluid can flow into the side flow pipe 5.

As another embodiment of the butterfly valve 21 according to the present invention, as shown in FIGS. 17 to 19, the valve body may be constituted by two plate-shaped valve bodies 33 sandwiching the side flow pipe 5.
In this case, the inlet at the upstream end of the side flow pipe 5 has an enlarged diameter part 35 that expands in diameter in a flat shape (see FIG. 18), and the side surface of the upstream end of the enlarged diameter part 35 comes into contact with the pipe wall of the main flow pipe 3. The two valve bodies 33 of the butterfly valve 21 are provided so as to sandwich the enlarged diameter portion 35 from above to above.
With such a structure, all the first fluid can flow into the side flow pipe 5 when the butterfly valve 21 is fully closed.

The butterfly valve 21 may be operated manually, but similarly to the operation of the shutter valve 9 (see FIGS. 4 to 8), it can be automatically controlled by providing a pressure detection device, a flow rate detection device, a flow velocity detection device, an actuator, and a control section. It goes without saying that you can do it this way.

Note that the flow passage cross-sectional area adjustment valves (shutter valve 9, butterfly valve 21) shown in the above embodiments are those that adjust the flow passage cross-sectional area of the gap main flow passage 8a among the main flow passages. Therefore, the shutter valve 9 was arranged in the main gap passage 8a, and the butterfly valve 21 was arranged so as to be in contact with the upstream end of the side flow pipe 5.
However, in the flow passage cross-sectional area adjusting valve of the present invention, for example, in the vicinity of the upstream end of the secondary flow pipe, there is a gap between the main flow passage 8 and the upstream end further upstream than the upstream end of the secondary flow pipe. It may be placed with the space left open. Even in this case, the flow rate of the first fluid flowing into the sub-flow pipe 5 can be adjusted by adjusting the flow-path cross-sectional area of the main flow path 8 at the position where the flow-path cross-sectional area adjustment valve is arranged.
For the same reason, the flow passage cross-sectional area adjusting valve of the present invention may be arranged so as to be in contact with the downstream end of the auxiliary flow pipe, or may be arranged near the downstream end of the auxiliary flow pipe.

1 Fluid mixing device (Embodiment 1)
3 Main flow pipe 5 Side flow pipe 7 Second fluid supply pipe 7a Outlet part 8 Main flow path 8a Gap main flow flow 9 Shutter valve 11 Venturi pipe 11a Throat 13 Plate body 13a Recess 15 Pressure detection device 16 Flow rate detection device 17 Actuator 19 Control Part 20 Fluid mixing device (Embodiment 2)
21 Butterfly valve 23 Valve body 23a Opening part 25 Rotating shaft 27 Operating part 29 Gap 31 Baffle plate 33 Valve body 35 Expanded diameter part

Claims (13)

A fluid mixing device that mixes a gaseous first fluid flowing through a mainstream pipe by supplying a liquid second fluid midway through the mainstream pipe, comprising:
a secondary flow pipe disposed within the main flow pipe and having a smaller diameter than the main flow pipe; a second fluid supply pipe that supplies the second fluid to the secondary flow pipe; A fluid mixing device comprising: a flow passage cross-sectional area adjustment valve that adjusts the flow rate of the first fluid flowing into the secondary flow pipe by adjusting the flow passage cross-sectional area of the main flow passage. 2. The fluid mixing device according to claim 1, wherein the main flow pipe is provided with a Venturi pipe, and the outlet side of the side flow pipe is arranged at a throat of the Venturi pipe or an upstream side thereof. an actuator that operates the flow path cross-sectional area adjustment valve; a detection device that detects the pressure of fluid flowing upstream and/or downstream of the flow path cross-sectional area adjustment valve; and based on a detection signal of the detection device. The fluid mixing device according to claim 1 or 2, further comprising a control section that controls the actuator. An actuator that operates the flow path cross-sectional area adjustment valve, a detection device that detects the flow rate or flow velocity of the fluid flowing through the side flow pipe, and a control unit that controls the actuator based on a detection signal from the detection device. The fluid mixing device according to claim 1 or 2, characterized in that: an actuator that operates the flow path cross-sectional area adjustment valve; a first flow rate detection device that detects the flow rate of fluid flowing upstream of the flow path cross-sectional area adjustment valve; and a first flow rate detection device that detects the flow rate of the fluid flowing through the gap main flow path. 3. The actuator according to claim 1, further comprising: a second flow rate detection device, and a control unit that controls the actuator based on detection signals from the first flow rate detection device and the second flow rate detection device. Fluid mixing device. The fluid mixing device according to any one of claims 1 to 5, wherein the flow path cross-sectional area adjustment valve is configured to be able to close the gap main flow path. 7. The fluid mixing device according to claim 1, wherein the flow passage cross-sectional area adjusting valve is a shutter valve whose plate-shaped body is movable in a direction crossing the main flow passage. 7. The flow path cross-sectional area adjusting valve is a butterfly valve that rotates a plate-shaped valve body around an axis perpendicular to the gap main flow path, according to any one of claims 1 to 6. Fluid mixing device. 9. The fluid mixing device according to claim 8, wherein the butterfly valve has an opening at a portion corresponding to an inlet of the side flow pipe in a closed state. 10. The fluid mixing device according to claim 9, wherein an upstream end of the secondary flow pipe is bent toward a wall of the main flow pipe. The inlet of the secondary flow pipe is disposed at the center of the main flow pipe, and the butterfly valve and the pipe of the secondary flow pipe are disposed on the pipe wall near the inlet of the secondary flow pipe when the butterfly valve is closed. The fluid mixing device according to claim 9, further comprising a baffle plate for closing a gap with the wall. 9. The fluid mixing device according to claim 8, wherein the butterfly valve is constituted by two plate-shaped valve bodies sandwiching the side flow pipe. The inlet of the secondary flow pipe has an enlarged diameter part that expands in diameter in a flat shape, and the side surface of the upstream end of the enlarged diameter part is in contact with the pipe wall of the main flow pipe, and the two valves of the butterfly valve 13. The fluid mixing device according to claim 12, wherein the body is provided so as to sandwich the enlarged diameter portion.

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