JP2011200808A - Method and apparatus for mixing fluid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for mixing fluids, which can be applied to combustible or corrosive fluids, and an apparatus for mixing the fluids, the structure of which is simplified.SOLUTION: In a venturi type apparatus 1 for mixing the fluids, a venturi tube 5 is arranged on a main pipeline 3, and a liquid second fluid is supplied to a gaseous first fluid which is supplied from the upstream side of the venturi tube 5 at the throat part 9 of the venturi tube 5 or the upstream side thereof, and then both the fluids are mixed with each other. The venturi apparatus 1 for mixing the fluids includes: a branched tube 7 which is branched from the main pipeline 3, and in which the cross section of a flow passage has a small diameter part smaller than the diameter of the main pipeline 3, and the outlet side of which is connected to the throat part 9 of the venturi tube or the upstream side thereof; a porous body 12 which is arranged in the small diameter part of the branched tube 7 or in the vicinity thereof and used for supplying the second fluid; and a flow rate control valve 15 which is arranged on the main pipeline 3 on the downstream side of the branched part of the branched tube 7 and is used for controlling the flow rate of the fluid flowing in the main pipeline 3.

Description

  The present invention relates to a fluid mixing method and apparatus for performing mixing by adding another fluid to a fluid flowing through a mainstream 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, the import of LNG rich in methane components has increased, and in many cases the heat is increased for city gas. The calorific value is adjusted by mixing natural gas with a calorific value adjusting agent such as liquefied petroleum gas (hereinafter referred to as “LPG”).
As such a calorific value adjusting method, for example, Japanese Patent Laid-Open No. 63-265994 (Patent Document 1) supplies vaporized natural gas to a venturi-type liquid / gas mixer, and generates a high-speed flow and low pressure generated in a venturi pipe. A technique for atomizing, evaporating, and mixing a calorific value adjusting agent supplied in a liquid state to a venturi tube is disclosed.

  Japanese Patent Laid-Open No. 53-131328 (Patent Document 2) relating to a fuel vaporizer for an internal combustion engine, although not a city gas heat increasing device, discloses a technique for providing a throttle member that can move in the flow path direction in a venturi pipe. Is disclosed.

  Further, JP-A-8-75621 (Patent Document 3) relates to a constant flow rate sampling device, in which a spindle-shaped core is fixed in a tube serving as a gas flow path, and a throat portion disposed outside the core is pulsed. A technique for changing a cross-sectional area of a flow path by moving it in the flow path direction by a motor is disclosed.

  Japanese Utility Model Laid-Open No. 56-41210 (Patent Document 4) and Japanese Patent Application Laid-Open No. 4-248414 (Patent Document 5) relate to a flow rate measurement control device, and a circular cross-sectional area is provided in the flow direction in the throat portion of the Venturi tube. A technique is disclosed in which a movable body having a surface that changes along the line is disposed, and the movable body is driven by a motor disposed in a flow path.

JP 63-265994 A JP-A-53-131328 JP-A-8-75621 Japanese Utility Model Publication No. 56-41210 JP-A-4-248414

  The flow rate of natural gas varies according to the city gas demand. On the other hand, when the flow rate of the Venturi pipe changes, the flow velocity and the effect of generating low pressure are reduced. Therefore, if the cross-sectional area of the venturi pipe throat is constant, such as that disclosed in Patent Document 1, the change in the amount of city gas demand will change. There is a problem that if it is large, it cannot be handled. Therefore, when using the technique of Patent Document 1, it is necessary to prepare venturi pipes having different sizes according to the flow rate range, and there is a problem such as complication of the apparatus.

In this regard, in the technique described in Patent Document 2, even if the flow rate of the air passing through the venturi pipe varies, the axial position of the throttle member is changed so as to cope with it.
However, Patent Document 2 does not disclose a driving method for moving the aperture member in the axial direction. Also, if the drive source is outside the flow path, the drive shaft will penetrate outside the flow path, and the frequently moving surface will be sealed, so the fluid is flammable or dangerous. If so, there will be a leakage problem.

Also in Patent Document 3, since the throat portion disposed outside the spindle core is moved in the direction of the flow path, it is possible to cope with fluctuations in the gas flow rate, but the drive section is outside the flow path. As in the case of Patent Document 2, the drive mechanism penetrates the inside and outside of the flow path, and there is a problem of sealing performance on the movable surface (sliding surface).
Similarly, in Patent Documents 4 and 5, although it is possible to cope with fluctuations in the gas flow rate, a motor as a drive source is disposed in the gas flow path, so that the structure becomes complicated. Considering the inflow of fluid into the motor unit that requires driving energy, there is a problem that it is difficult to apply to fluids that are flammable or corrosive.
Furthermore, in the one disclosed in Patent Document 5, the “flow rate” is controlled based on the pressure and temperature. However, what is important from the viewpoint of mixing the fluid is the throat of the venturi tube in accordance with the fluctuation of the flow rate. This is to control the flow velocity of the part, and such control is not possible with the one of Patent Document 5.

  The present invention has been made to solve the above-described problems, and has an object to provide a fluid mixing method and apparatus that have a simple structure and can be applied to a flammable or corrosive fluid.

(1) The fluid mixing method according to the present invention is a fluid mixing method in which both fluids are mixed by supplying a liquid second fluid in the middle of the main flow path to the gaseous first fluid flowing in the main flow path. And
A branch channel having a small-diameter portion whose channel cross-section is smaller than that of the main channel is branched from the main channel, and the outlet side of the branch channel is downstream of the branch position of the branch channel in the main channel And the second fluid supply portion made of a porous body is provided at or near the small-diameter portion of the branch channel, and the flow rate of the main channel between the branch position and the outlet position of the branch channel The flow rate of the first fluid flowing through the small-diameter portion of the branch flow channel is adjusted so that the second fluid oozing out from the porous body is atomized and mixed by the first fluid. It is characterized by maintaining the required flow rate.

(2) Further, in the above (1), the porous body is arranged so as to straddle the inside and the outside of the outlet of the branch flow path.

(3) Further, in the above-described (1) or (2), a venturi pipe is provided in the main flow path, and an outlet side of the branch flow path is arranged at a throat portion of the venturi pipe or upstream thereof. It is a feature.

(4) A fluid mixing apparatus according to the present invention is a fluid mixing apparatus that mixes both fluids by supplying a liquid second fluid in the middle of the main flow pipe to the gaseous first fluid flowing through the main flow pipe. ,
A branch pipe provided by branching from the main flow pipe, having a small-diameter portion whose flow path cross section is smaller than that of the main flow pipe, and having an outlet side connected downstream of the branch position in the main flow pipe; and the branch pipe A second fluid supply part made of a porous body that is provided at or near the small diameter part and supplies the second fluid, and a downstream side of the branch part of the branch pipe in the main flow pipe and an outlet of the branch pipe And a flow rate adjusting valve provided on the upstream side of the unit for adjusting the flow rate flowing through the main flow pipe.

(5) Further, in the above (4), the second fluid supply section made of the porous body is arranged so as to straddle the inside and the outside of the outlet of the branch channel. It is.

(6) Further, in the above (4) or (5), a venturi pipe is provided in the main flow path, and the second fluid supply section is arranged at the throat of the venturi pipe or upstream thereof. It is what.

(7) Further, in any of the above (4) to (6), the flow passage cross-sectional area of the small diameter portion of the branch pipe has flowed in an amount assumed as the minimum flow rate of the first fluid. Sometimes, the flow velocity of the small diameter portion is set to a size that can maintain the flow velocity necessary for the second fluid that has oozed out of the porous body to be atomized and mixed by the first fluid. It is characterized by.

(8) Further, in the above (7), a detecting means for detecting the flow rate and / or pressure of the first fluid flowing through the branch pipe is provided, and the flow rate adjusting valve is based on a detection signal of the detecting means. Even when the flow rate of the first fluid fluctuates, the first fluid is always allowed to flow through the minimum flow rate through the branch pipe, and a flow rate exceeding the minimum flow rate is allowed to flow through the main flow pipe. It is characterized by that.

(9) Further, in any of the above (4) to (8), the crossing direction is provided so as to be branched from the main flow pipe, and the outlet side is shifted from the axis of the main flow pipe. And a second branch pipe connected to the pipe.

(10) Further, in the above (7), the first detection means for detecting the flow rate and / or pressure of the first fluid flowing through the branch pipe, and the outlet side is provided by branching from the main flow pipe A second branch pipe connected in an intersecting direction shifted from the axis of the main flow pipe, and a second detection means for detecting the flow rate and / or pressure of the first fluid flowing through the second branch pipe. A second flow rate adjusting valve for adjusting the flow rate of the second branch pipe, and adjusting a flow rate adjusting valve provided in the main flow pipe based on a detection signal of the second detection means, and the first detection Adjusting the second flow rate adjustment valve based on the detection signal of the means,
Even when the flow rate of the first fluid fluctuates, the first fluid is always allowed to flow through the branch pipe, the flow exceeding the minimum flow is allowed to flow through the second branch pipe, and the second branch is further passed. When the flow rate of the pipe exceeds a predetermined flow rate, the excess flow rate is caused to flow through the main flow pipe.

  In the present invention, a branch channel having a small-diameter portion whose channel cross section is smaller than that of the main channel is provided by branching from the main channel, and an outlet side of the branch channel is disposed in the main channel. A supply portion made of a porous body that supplies a liquid second fluid is provided at or near the small diameter portion, and the flow rate of the main flow path is adjusted to adjust the flow rate of the first fluid flowing through the small diameter portion of the branch flow path. Since the flow rate is maintained at a flow rate necessary for the second fluid that has oozed out of the porous body to be atomized and mixed by the first fluid, a high mixing effect is achieved over a wide flow rate range. It becomes possible to obtain reliably. In addition, there is no need for moving parts such as a movable body, and therefore no driving part for driving the moving parts is required, and the structure can be simplified, and it can be used for flammable and corrosive fluids. Is applicable.

It is explanatory drawing which showed typically the venturi type fluid mixing apparatus which concerns on Embodiment 1 of this invention. It is a figure which expands and shows a part of FIG. It is explanatory drawing of the other aspect regarding arrangement | positioning of the porous body in one embodiment of this invention. It is explanatory drawing of other embodiment of this invention. It is explanatory drawing of other embodiment of this invention.

[Embodiment 1]
The fluid mixing apparatus according to the present embodiment is used when producing city gas by increasing the temperature by adding LPG to natural gas obtained by vaporizing LNG. In the first embodiment, a venturi pipe is installed in the mainstream pipe to constitute a venturi type mixing device.

As shown in FIG. 1, the basic configuration of the venturi-type mixing apparatus 1 according to the present embodiment is a venturi pipe 5 provided in a main flow pipe 3 through which natural gas flows, and an outlet flow channel cross section than the main flow pipe 3. Is provided with a branch pipe 7 having a small diameter branched from the main flow pipe 3, the outlet side of the branch pipe 7 is connected to the venturi throat portion 9 or the upstream side thereof, and LPG is supplied into the outlet portion of the branch pipe 7. The LPG supply pipe 11 is inserted, and the porous body 12 is attached to the tip of the LPG supply pipe 11.
Further, in the venturi type mixing apparatus 1 of the present embodiment, the branch pipe 7 is provided with a flow rate detector 13 for detecting the flow rate of natural gas flowing through the branch pipe 7, and the venturi pipe 5 and the branch pipe in the main flow pipe 3 are provided. A flow rate adjusting valve 15 is provided between the branching portions, and the opening degree of the flow rate adjusting valve 15 is adjusted based on the detection signal of the flow rate detector 13.
Hereinafter, each configuration will be described in detail.

<LPG supply pipe>
The LPG supply pipe 11 is for supplying LPG into the venturi pipe 5, and the porous body 12 serving as the LPG supply place is arranged in the outlet pipe of the branch pipe 7 as shown in FIG. . By disposing the porous body 12 attached to the tip of the LPG supply pipe 11 in the outlet pipe of the branch pipe 7, the LPG oozed out of the porous body 12 by the natural gas having an increased flow velocity through the branch pipe 7 is atomized. Can be supplied while being atomized and mixed effectively.
That is, the LPG supplied from the LPG supply pipe 11 is atomized by the natural gas flow that oozes out from the porous body 12 and flows on the peripheral surface of the porous body 12, and is mixed with the natural gas.
Examples of the porous body 12 include, for example, a sintered filter (polymer, metal, ceramic) formed in a bottomed cylindrical shape.
The end face on the front end side of the porous body 12 is completely sealed so that LPG does not exude from the end end face, so that the amount of exudation of LPG only from the peripheral surface of the porous body 12 can be increased. Therefore, mixing and atomization with natural gas flowing through the branch pipe 7 can be performed more effectively.

The position of the porous body 12 may be disposed on the axis that is the center of the branch pipe 7, or may be shifted from the axis.
Further, the supply direction from the LPG supply pipe 11 may be arbitrary. For example, it may be coaxial with the branch pipe 7, may be orthogonal, or may be in other directions.

  In the above example, the porous body 12 of the LPG supply pipe 11 is arranged in the outlet pipe of the branch pipe 7, but as shown in FIG. The porous body 12 may be disposed so as to straddle the inner side and the outer side of the outlet of the branch pipe 7. With this arrangement, the LPG that oozes from the porous body 12 can come into contact with both the natural gas flowing through the branch pipe 7 and the natural gas flowing through the venturi pipe 5. As a result, even when the flow velocity of the natural gas flowing through the branch pipe 7 and the venturi pipe 5 increases due to the change in the flow velocity of the natural gas, the natural gas with the increased flow velocity can be used for mixing and atomization.

<Branch pipe>
The branch pipe 7 branches from the upstream side of the venturi pipe 5 in the main flow pipe 3, and the outlet side thereof is connected to the upstream side of the venturi pipe throat portion 9 or the venturi pipe throat portion 9.
The flow passage cross-sectional area of the branch pipe 7 has a portion having a smaller diameter than the main flow pipe 3, and the flow rate of the natural gas flowing through the small diameter portion of the branch pipe 7 is faster than the flow rate of the natural gas flowing through the main flow pipe 3. It is set to be. The small diameter portion is generally disposed at the outlet of the branch pipe 7.
By increasing the flow rate of the natural gas at the small diameter portion disposed at the outlet of the branch pipe 7, the atomization of LPG supplied from the porous body 12 is promoted. In the present embodiment, as shown in FIG. 1 to FIG. 3, the tip of the branch pipe 7 has a reduced diameter, and is supplied from the branch pipe 7 and passes through the peripheral surface of the porous body 12. So that the flow rate is faster.
The LPG supplied from the porous body 12 at the outlet of the branch pipe 7 is mixed with the natural gas flowing through the branch pipe 7, and further merged with the natural gas supplied from the mainstream pipe in the venturi pipe 5, so that the throat of the venturi pipe Mixing is further promoted when passing through section 9.

  Arrangement | positioning by the side of the exit of the branch pipe 7 may be arbitrary. As shown in FIG. 1, it is most desirable to arrange it in the same direction as the venturi tube 5, but it is not particularly limited.

It is the flow velocity at the site where the porous body 12 is provided in the branch pipe 7 that greatly affects the atomization / mixing performance of LPG. This is because the flow rate is increased by flowing the natural gas through the branch pipe 7 having a smaller channel cross-sectional area than the main flow pipe 3, and the LPG is atomized and mixed by the natural gas having the increased flow speed.
The diameter of the portion of the branch pipe 7 where the porous body 12 is provided is such that the flow rate of natural gas flowing through the branch pipe 7 is the flow rate required for atomization / mixing of LPG even when the city gas is operated at the lowest flow rate. The diameter should be such that it can be maintained.
For example, assuming that the fluctuation range of the city gas flow is 300,000 Nm ³ / h to 6,000 Nm ³ / h, when the city gas flow rate is 6,000 Nm ³ / h, which is the lowest flow rate, natural gas is branched. The pipe diameter is such that the natural gas flow rate at the portion where the porous body 12 is provided in the branch pipe 7 at this time (small diameter portion in the branch pipe 7) maintains the flow speed necessary for atomization and mixing of LPG. And (At this time, the flow rate of natural gas flowing through the branch pipe 7 is the lowest flow rate assumed as the flow rate of natural gas.)
In addition, if the assumed minimum flow rate is always passed through the branch pipe 7, the LPG atomization / mixing can be realized with easy and stable control. In the following description, the minimum flow rate that provides a flow rate necessary for atomization / mixing of LPG in the branch pipe may be referred to as a predetermined value A.

  The flow rate required for atomization / mixing varies depending on the implementation case, but is generally in the range of 20 m / s or more. Therefore, the branch pipe 7 is configured so that the flow rate can be secured at the portion of the branch pipe where the porous body 12 is provided in the case of the assumed minimum flow rate of the city gas and the pressure loss is not excessively high. Should be set.

For example, the pipe diameter of the branch pipe 7 may be the same from the inlet side to the outlet side, but the cross-section of the portion where the porous body 12 is provided as a smaller-diameter portion smaller than the cross-section of the main flow pipe 3, Other portions may have a larger tube diameter than the small diameter portion. By making the pipe diameters other than the small diameter part larger than this, it is possible to avoid the pressure loss in the branch pipe 7 from becoming too large.
The diameter of the venturi tube throat portion 9 is designed so that the pressure loss at the maximum design flow rate does not become excessive for the application system.

<Flow detector>
The flow rate detector 13 is provided in the branch pipe 7 and detects the flow rate of natural gas flowing through the branch pipe 7.
It should be noted that a differential pressure detector is provided in place of the flow rate detector 13, and the pressure loss in the branch pipe 7 is detected. You may make it detect the flow volume of the natural gas which flows through.

<Flow control valve>
The flow rate adjustment valve 15 is provided between the venturi pipe 5 and the branch part of the branch pipe 7 in the main flow pipe 3, and adjusts the flow rate of natural gas flowing through the main flow pipe 3 based on the detection signal of the flow rate detector 13. As a result, the flow rate of natural gas flowing through the branch pipe 7 is set to a predetermined flow rate.

<Description of operation>
Next, the operation of the venturi type fluid mixing apparatus according to the present embodiment configured as described above will be described.
The natural gas supplied from the upstream side also flows to the branch pipe 7 when passing through the branch portion, and the LPG supplied from the porous body 12 is atomized and mixed on the outlet side of the branch pipe 7, and the venturi It flows into the tube throat 9. On the other hand, natural gas flowing through the main flow pipe 3 also flows into the venturi pipe throat 9. Therefore, the natural gas to which LPG has been added via the branch pipe 7 and the natural gas from the mainstream pipe 3 flow into the venturi throat section 9 and pass through the venturi throat section 9 to further increase the LPG. Mixing is promoted.

The flow rate of city gas increases or decreases depending on the demand. For example, when the city gas demand decreases and the flow rate of the fluid flowing through the flow path decreases, the total flow rate of the natural gas flowing through the branch pipe 7 and the main flow pipe 3 decreases. If the flow rate of natural gas flowing through the branch pipe 7 decreases below the predetermined value A, the flow velocity in the branch pipe 7 decreases, and there is a concern that LPG atomization / mixing becomes insufficient.
Therefore, when the flow rate detected by the flow rate detector 13 decreases below the predetermined value A, the flow rate of the natural gas flowing through the branch pipe 7 is maintained at the predetermined value A by reducing the opening of the flow rate adjustment valve 15. .
By maintaining the flow rate of natural gas flowing through the branch pipe 7 at a predetermined value A or higher, the flow rate in the branch pipe 7 is maintained, and the effect of atomization / mixing of LPG can be ensured.

Conversely, when the demand for city gas increases and the flow rate of the fluid flowing through the flow path increases, the flow rate of natural gas flowing through the branch pipe 7 and the main flow pipe 3 increases. When the flow rate of the natural gas flowing through the branch pipe 7 increases beyond a predetermined amount, the pressure loss increases.
Therefore, when the flow rate detected by the flow rate detector 13 increases from the predetermined value B, the opening degree of the flow rate adjustment valve 15 is increased to increase the amount flowing through the main flow pipe 3, and the flow rate of natural gas flowing through the branch pipe 7 is predetermined. The value B is set. Here, there is a relationship of the predetermined value B ≧ the predetermined value A.
By setting the flow rate of the natural gas flowing through the branch pipe 7 to a predetermined value A or more and B or less, the flow velocity in the branch pipe 7 is maintained within a predetermined range, and LPG can be sufficiently atomized and mixed, and the pressure loss is excessive. An increase can be prevented.

For example, the simplest control method is a case where the predetermined value A = predetermined value B = [natural gas flow rate at the lowest city gas flow rate (natural gas minimum flow rate)].
As in the previous example, assuming that the fluctuation range of the city gas flow rate is 300,000 Nm ³ / h to 6,000 Nm ³ / h, when the city gas flow rate is 6,000 Nm ³ / h, which is the lowest flow rate, A total amount of gas is flowed from the branch pipe 7, that is, a flow rate of a predetermined value A (= predetermined value B).
When the city gas flow rate exceeds 6,000 Nm ³ / h, the opening of the flow rate adjustment valve 15 is set so that the flow rate measured by the flow rate detector 13 installed in the branch pipe 7 maintains a predetermined value A. The natural gas flow rate increase is increased from the main flow pipe 3 by increasing the flow rate. That is, even if the city gas flow rate fluctuates, the natural gas flow rate of the predetermined value A always flows through the branch pipe 7. By doing so, a flow rate necessary for atomization / mixing is always supplied from the branch pipe 7. Further, the velocity component from the main flow tube 3 contributes to the direction of further increasing the flow velocity in the venturi tube throat 9.
In the above description, the predetermined value A is [natural gas flow rate at the minimum city gas flow rate (natural gas minimum flow rate)], but may be simply [minimum city gas flow rate].

As described above, according to the present embodiment, the natural gas flow rate of the branch pipe 7 at the position where the porous body 12 serving as the LPG supply unit is disposed even if the flow rate flowing through the flow path changes greatly. The flow rate can be maintained at a predetermined level, and the effect of atomization / mixing of LPG can be obtained and the pressure loss can be prevented from becoming excessively large.
Further, in the present embodiment, the structure is simple, not the structure in which the flow passage cross-sectional area of the venturi tube throat portion 9 is changed by the movable body as in the conventional example, and the sliding portion outside the flow passage. There is no need to seal the sliding surface, and no additional power is required.
Moreover, it can be applied to fluids that are flammable, corrosive, and dangerous without contamination.
Furthermore, since it is not necessary to provide a drive source outside, it is not necessary to insert a drive shaft into the flow path, for example.

[Embodiment 2]
FIG. 4 is an explanatory view schematically showing a venturi type fluid mixing apparatus 17 according to Embodiment 2 of the present invention. 4, the same parts as those in FIG. 1 are denoted by the same reference numerals.
The venturi-type fluid mixing device 17 of this embodiment branches the branch pipe 7 into two on the way to form branch pipes 7a and 7b, and a porous body at the outlet of the branch pipe 7a as in the embodiment. 12 and the outlet side end portion of the branch pipe 7b is connected in the tangential direction of the outer peripheral portion of the Venturi pipe flow path cross section or in the intersecting direction in which the axis is shifted with respect to the axis line of the Venturi pipe 5.
A flow rate detector 13 is disposed in the branch pipe 7a, and a flow rate detector 23 and a flow rate adjustment valve 25 are disposed in the branch tube 7b.

  As described above, the branch pipe 7 is further branched and one of the branch pipes 7b is connected in the tangential direction of the outer peripheral portion of the venturi pipe flow path cross section or in the intersecting direction in which the axis is shifted from the axis of the venturi pipe 5. Thus, a swirling flow is generated in the venturi pipe 5 by the natural gas supplied from the branch pipe 7b. This increases the flow rate through the venturi throat 9 and promotes mixing of the LPG already added.

The flow rate control method in the present embodiment configured as described above will be described below.
As in the previous example, assuming that the fluctuation range of the city gas flow rate is 300,000 Nm ³ / h to 6,000 Nm ³ / h, when the city gas flow rate is 6,000 Nm ³ / h, which is the lowest flow rate, A total amount of gas is flowed from the branch pipe 7a, that is, a flow rate of a predetermined value A. At this time, the flow rate adjustment valve 15 and the flow rate adjustment valve 25 are fully closed.
When the city gas flow rate is greater than 6,000 Nm ³ / h, the opening of the flow rate adjustment valve 25 is adjusted so that the flow rate measured by the flow rate detector 13 installed in the branch pipe 7a maintains a predetermined value A. The natural gas flow rate increase is made to flow from the branch pipe 7b. That is, even if the city gas flow rate fluctuates, the natural gas flow rate of the predetermined value A always flows through the branch pipe 7a. By doing so, a flow rate necessary for atomization / mixing is always supplied from the branch pipe 7a. Further, the velocity component from the branch pipe 7b generates a swirling flow in the venturi pipe 5 and contributes to the direction of further increasing the flow velocity in the throat portion 9 of the venturi pipe.
When the city gas flow rate further increases and the flow rate measured by the flow rate detector 23 installed in the branch pipe 7b reaches a predetermined value C, the flow rate measured by the flow rate detector 23 is kept at the predetermined value C. Then, the opening of the flow rate adjusting valve 15 is increased so that an increase in the natural gas flow rate flows from the main flow pipe 3.

  Here, the predetermined value C is a maximum value of the flow rate of natural gas flowing through the branch pipe 7b, and is set in a range where the pressure loss of the branch pipe 7b does not become excessive. For example, the pressure loss when the natural gas flow rate of the predetermined value C flows through the branch pipe 7b is equal to or less than the pressure loss in the branch pipe 7a when the natural gas flow rate of the predetermined value A flows through the branch pipe 7a. To do.

  As described above, according to the present embodiment, even when the flow rate flowing through the flow path is greatly changed, the effect of atomizing / mixing LPG can be obtained and the pressure loss is not excessively increased. it can. That is, the natural gas flow rate of the branch pipe 7a at the position where the porous body 12 serving as the LPG supply portion is disposed can be maintained at a predetermined flow rate, and mixing is promoted by the swirling flow from the branch pipe 7b. Further, the velocity component from the main flow tube 3 contributes to the direction of increasing the flow velocity in the venturi tube throat 9.

In the example shown in FIG. 4, the branch pipe 7 is further branched into the branch pipe 7 b that generates the swirling flow. However, a branch pipe for generating the swirling flow is provided directly from the main flow pipe 3 separately from the branch pipe 7. You may make it branch. The position where the branch pipe 7b is branched directly from the main flow pipe 3 may be either upstream or downstream of the flow rate adjustment valve 15.
Further, in the example shown in FIG. 4, the number of the branch pipes 7b that generate the swirling flow is one, but a plurality of, for example, two, three or more, may be arranged and connected in the axial direction of the venturi pipe. Good.
Furthermore, when a plurality of branch pipes for generating a swirl flow are provided, a plurality of branch pipes may be connected in the venturi pipe circumferential direction.

[Embodiment 3]
FIG. 5 is an explanatory view schematically showing a venturi type fluid mixing apparatus 19 according to Embodiment 3 of the present invention. In FIG. 5, the same parts as those in FIG.
The venturi type fluid mixing device 19 of the present embodiment is provided with a branch pipe 7c that branches from between the flow regulating valve 15 and the venturi pipe 5 in addition to the configuration shown in the first embodiment, and the end of the branch pipe 7c. The portion is connected to the downstream side of the venturi throat portion 9.
As in the second embodiment, the connection mode is, for example, the tangential direction of the outer peripheral portion of the cross section of the flow path or the crossing direction in which the axis is shifted with respect to the axis of the venturi tube 5.

  LPG can be mixed more effectively by generating a swirling flow of natural gas at the downstream side of the throat 9 of the venturi pipe.

  In the above-described embodiment, an example in which the venturi pipe 5 is provided in the main flow pipe 3 is shown. However, the present invention is not limited to this, and the branch pipe 7 flows without the venturi pipe 5 being provided. LPG is atomized by the natural gas stream and mixed with natural gas. However, by providing the venturi tube 5, as described above, there is an effect that atomization / mixing in the throat portion 9 of the venturi tube is further promoted.

  The present invention can be applied to the use of mixing both fluids by supplying the second fluid to the first fluid flowing through the main channel in the middle of the main channel.

DESCRIPTION OF SYMBOLS 1, 17, 19 Venturi type mixing device 3 Main flow pipe 5 Venturi pipe 7 Branch pipe 7a, 7b, 7c Branch pipe 9 Venturi pipe throat part 11 LPG supply pipe 12 Porous body 13, 23 Flow rate detector 15, 25 Flow rate adjustment valve

Claims (10)

A fluid mixing method of mixing both fluids by supplying a liquid second fluid in the middle of the main flow path to the gaseous first fluid flowing through the main flow path,
A branch channel having a small-diameter portion whose channel cross-section is smaller than that of the main channel is branched from the main channel, and the outlet side of the branch channel is downstream of the branch position of the branch channel in the main channel And the second fluid supply portion made of a porous body is provided at or near the small-diameter portion of the branch channel, and the flow rate of the main channel between the branch position and the outlet position of the branch channel The flow rate of the first fluid flowing through the small-diameter portion of the branch flow channel is adjusted so that the second fluid oozing out from the porous body is atomized and mixed by the first fluid. A fluid mixing method characterized by maintaining a necessary flow rate.   The fluid mixing method according to claim 1, wherein the porous body is disposed so as to straddle the inside and the outside of the outlet of the branch channel.   The fluid mixing method according to claim 1 or 2, wherein a venturi pipe is provided in the main flow path, and an outlet side of the branch flow path is arranged at a throat portion of the venturi pipe or upstream thereof. A fluid mixing device that mixes both fluids by supplying a liquid second fluid in the middle of the main flow pipe to the gaseous first fluid flowing through the main flow pipe,
A branch pipe provided by branching from the main flow pipe, having a small-diameter portion whose flow path cross section is smaller than that of the main flow pipe, and having an outlet side connected downstream of the branch position in the main flow pipe; and the branch pipe A second fluid supply part made of a porous body that is provided at or near the small diameter part and supplies the second fluid, and a downstream side of the branch part of the branch pipe in the main flow pipe and an outlet of the branch pipe A fluid mixing apparatus comprising: a flow rate adjusting valve provided on the upstream side of the unit for adjusting a flow rate flowing through the main flow pipe.   The fluid mixing apparatus according to claim 4, wherein the second fluid supply unit made of the porous body is arranged so as to straddle the inside and the outside of the outlet of the branch channel.   The fluid mixing apparatus according to claim 4 or 5, wherein a venturi pipe is provided in the main flow path, and the second fluid supply section is disposed at a throat section of the venturi pipe or upstream thereof.   When the flow rate cross-sectional area of the small-diameter portion of the branch pipe flows in an amount assumed as the minimum flow rate of the first fluid, the second fluid that has flowed out of the porous body has a flow velocity of the small-diameter portion. The fluid mixing device according to any one of claims 4 to 6, wherein the fluid mixing device is set to a size capable of maintaining a flow rate necessary for being atomized and mixed by the first fluid.   Detection means for detecting the flow rate and / or pressure of the first fluid flowing through the branch pipe is provided, and the opening of the flow rate adjustment valve is adjusted based on the detection signal of the detection means, so that the flow rate of the first fluid varies. 8. The fluid mixing apparatus according to claim 7, wherein the first fluid is always allowed to flow through the branch pipe to the minimum flow rate, and a flow rate exceeding the minimum flow rate is caused to flow through the main flow pipe. .   9. A second branch pipe provided by branching from the main flow pipe and having an outlet side connected in an intersecting direction with an axial center shifted from the axis of the main flow pipe. The fluid mixing apparatus according to any one of the above. A first detecting means for detecting the flow rate and / or pressure of the first fluid flowing through the branch pipe; and an intersection provided by branching from the main flow pipe and having an outlet side shifted from the axis of the main flow pipe A second branch pipe connected in the direction, second detection means for detecting the flow rate and / or pressure of the first fluid flowing through the second branch pipe, and a second flow rate adjustment for adjusting the flow rate of the second branch pipe A flow rate adjusting valve provided in the main flow pipe based on a detection signal of the second detection means, and adjusting the second flow rate adjustment valve based on the detection signal of the first detection means And
Even when the flow rate of the first fluid fluctuates, the first fluid is always allowed to flow through the branch pipe, the flow exceeding the minimum flow is allowed to flow through the second branch pipe, and the second branch is further passed. 8. The fluid mixing apparatus according to claim 7, wherein when the flow rate of the pipe exceeds a predetermined flow rate, the excess flow rate is caused to flow through the main flow pipe.

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