JP2611182B2 - Degassing 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 deaeration device for controlling the amount of dissolved gas in a fluid such as water.

[0002]

2. Description of the Related Art A technique for controlling the amount of dissolved gas in a fluid such as removing unwanted dissolved gas from water or other solution fluid as much as possible or dissolving a desired gas in the fluid. It is believed that the necessity of this technology will continue to increase in various fields including the semiconductor industry, the pharmaceutical industry, the food industry, the analysis industry, and the water supply and sewerage business, as well as now and in the future.

For example, in the semiconductor industry, the amount of oxygen dissolved in pure water has become a problem. This is because, when the silicon surface is hydrogen-terminated by immersing it in a hydrofluoric acid solution, the oxidation reaction is more predominant than the chemical reaction for realizing the hydrogen termination. Therefore, it is necessary to reduce the amount of dissolved oxygen in pure water. Conventional techniques suitable for this include a bubbling method and a vacuum degassing method.

[0004] In order to maintain the equilibrium of the dissolved gas amount in proportion to the external partial pressure, if the external partial pressure of oxygen is reduced, the dissolved amount is also reduced.
In the bubbling method, in order to realize this, a large amount of high-purity inert gas (typically, argon gas) is passed through the fluid as fine bubbles. This technique is often employed not only in the semiconductor industry, but also generally in electrochemical lab sites. This is because dissolved oxygen and, in some cases, dissolved nitrogen are more active reactive species than the reaction desired in the experiment. In addition, in the electrochemical field, such a bubbling method is employed to remove undesired dissolved gases or conversely dissolve a desired gas even when controlling various chemical reactions using a solvent other than pure water. It may be done.

On the other hand, in the vacuum degassing method, the external partial pressure of dissolved gas such as oxygen is reduced by literally setting the fluid outer space to a vacuum (low pressure) environment. In an actual apparatus, a fluid to be treated is sprayed into a vacuum chamber in order to increase the efficiency.

[0006]

However, each of the above-mentioned conventional methods for controlling the amount of dissolved gas has problems. The bubbling method requires a fluid storage tank for performing the bubbling, and cannot perform bubbling while maintaining a stable fluid flow in the flow path. This is because the generation of bubbles in the fluid flow path generally configured as a pipe impedes the flow of the fluid. Also, it is difficult to recover the gas used for bubbling. If the bubbling device could be made quite small, these disadvantages would be alleviated considerably, but as long as the technology proposed so far was followed,
Unnecessary dissolved gas can be almost driven out only by the bubbling method, and a large-sized apparatus (tank) is required to increase the efficiency to shorten the processing time.
Therefore, a large amount of expensive high-purity inert gas must also be used.

[0007] In the case of the vacuum degassing method, the size of the apparatus is as large as that of the bubbling apparatus. When this method is followed, in order to prevent the backflow of pure water from the vacuum chamber, water must be injected from a height higher than 10 m, which is a water height equivalent to at least one atmosphere. Therefore, the construction of a huge facility called a vacuum degassing tower is inevitable, not only uneconomical, but also extremely poor in flexibility.

However, the need for controlling the amount of dissolved gas in a fluid is increasing. For example, (1) To reduce the rate of spoilage of foods, etc., to reduce the amount of oxygen in water, (2) To prevent rust in various pipes such as water and sewage pipes, reduce the amount of dissolved oxygen in the water flow in the pipes. (3) To improve the accuracy of chemical reaction control using various solutions,
I want to remove dissolved gas that is a factor that hinders the target reaction from the solution. (4) In chromatographic analysis, various gases dissolved in the solution to be analyzed produce spectral peaks as noise. Want to reduce the amount of dissolved gas in the solution in order to increase the analysis accuracy. (5) In the case of radiation detection using isotopes, radioactive gas such as radon dissolved in the target solution becomes a problem. (6) In the case of a fluid used in a high pressure environment such as a turbine, the dissolved gas is likely to separate and become a gas-liquid mixed state, leading to a serious accident. In some cases, there is a real and varied need to remove dissolved gases as much as possible.

In order to meet such various demands,
First of all, unlike conventional degassing devices or air intake devices, there must be no restrictions on the use or location of the device in terms of the structure of the device, or the cost must be high including maintenance and management costs. It must be highly flexible, with no restrictions on where it is used. On top of that, it is also satisfactory in performance, and it is possible to efficiently and reliably remove unnecessary gas from various fluids represented by pure water, or to dissolve the desired gas efficiently Must be something. The present invention has been made from such a point of view.

[0010]

In order to achieve the above object, according to the present invention, only a single processing stage as in the prior art is used.
Rather than degassing unnecessary gas from the fluid or entering the desired gas into the fluid, cascade the degassing part of the unnecessary gas and the gas inlet part other than the unnecessary gas in the fluid flow path. It is proposed to provide a device structure using a gas permeable membrane for the deaeration section and the intake section. However, as necessary and sufficient, the number of processing stages should be minimized, and the deaeration section and the intake section are each one, and an additional deaeration section is provided after the intake section. I will not do it.

In other words, in other words, in the present invention, two or more portions in which a part or the whole of the peripheral wall through which the fluid flows along the inner surface is a gas permeable membrane are provided in the middle of the fluid flow path through which the fluid flows. The outer space of one of the gas permeable membranes is a negative pressure to serve as a deaeration section, and the outer space of the other gas permeable membrane is a positive pressure filled with a predetermined gas and serves as an inlet section. A ventilating device constituted only by one inlet is proposed.

In addition to the above basic configuration, the present invention further provides a device having a more desirable lower configuration. In the present invention, there is also provided: (a) an outer space of the one gas permeable membrane in the degassing section accommodates the gas permeable membrane; The internal space of the closed vessel, and the external space of the one gas permeable membrane is set to a negative pressure by exhausting the internal space by the exhaust device, while the other gas permeable membrane of the air inlet is formed. The external space is also the internal space of the second closed container that contains the gas permeable membrane, and the gas supplied by the gas pressure pump connected to the second closed container is filled in the internal space of the second closed container. And the outer space of the other gas permeable membrane is made to have the above positive pressure; and (b) used in the degassing part and the gas inlet part, respectively. The above gas permeable membrane is A hollow cylindrical member having an inlet opening to enter therein and an outlet opening through which fluid flows out, and having a peripheral wall through which the fluid flows from the inlet opening toward the outlet opening and along the inner surface thereof; A venting device is also proposed.

[0013]

FIG. 1 shows a schematic structure of a main part of an air intake / removal device 100 according to an embodiment of the present invention.
In order to realize the present invention according to the gist configuration as already described, two or more parts in which a part or all of the peripheral wall is a gas permeable membrane 12 are provided in the middle of the fluid flow path in which the fluid F flows. The outer space 22 of the gas permeable membrane 12 may be a negative pressure to be a deaerator 91, and the outer space 22 of the other gas permeable membrane 12 may be a positive pressure filled with a predetermined gas 52 and an inlet 92. But,
The illustrated embodiment has the following device configuration more specifically.

First, both the degassing section 91 and the air inlet section 92 are directed from the inlet opening 11 into which the fluid F flows into the outlet opening 12 through which the fluid F flows out, and the fluid F flows along the inner surface thereof. A hollow cylindrical member 10 having a peripheral wall is provided. In the case of this embodiment, in particular, the hollow cylindrical member 10 itself is constituted by a gas permeable membrane 12. In other words, in this embodiment, all of the peripheral wall of the hollow cylindrical member 10 is cylindrical (it may be called a tube or a hose because it is often quite long as described later). Gas permeable membrane 12
It is constituted by. Here, the gas permeable membrane 12 referred to in the present invention refers to a gas permeable membrane having a myriad of fine-diameter holes that do not allow a liquid to be processed to pass therethrough but allow a gas to be deaerated to pass therethrough. Such components are already readily available on the market, as will be exemplified later.

In this embodiment, each hollow cylindrical member 10 is housed in a closed container 20, so that each hollow cylindrical member 10 or the outer space 22 of the gas permeable membrane 12 substantially corresponds to the hollow cylindrical member. It is an internal space of a closed container 20 for storing the 10. An exhaust device 40, which can be constituted by a general exhaust pump 41, is connected to the closed container 20 that constitutes the degassing section 91, and when it operates, the gas permeable membrane 12 that is the internal space of the closed container 20 is operated. The outer space 22 becomes relatively negative pressure. On the other hand, a gas pumping device 50, which can be constituted by, for example, a compressor 53, is connected to the closed container 20 on the side of the inlet section 92, and when this operates, the gas to be fed into the fluid F is stored. The incoming gas 52 from the gas source 51 is supplied under pressure into the internal space of the sealed container 20 (the external space 22 of the gas permeable membrane 12), and the internal space 22 becomes relatively positive.
However, the gas pumping device 50 and the gas source 51 do not necessarily have to be separate functional members. For example, in the case of a so-called gas cylinder 54, this serves as both the gas pumping device 50 and the gas source 51.

Both the gas permeable membrane 12 of the degassing section 91 and the gas permeable membrane 12 of the inlet section 92 are degassed in series in the fluid path of the fluid F and cascade (continuously) with each other. The inlet opening 11 of the gas permeable membrane 12 on the side of the gas inlet 91 is connected to the outlet end of the inlet pipe 31 through which the fluid F flows, and is connected to the inlet side connector 21 of the sealed container 20. The outlet opening 13 of the membrane 12 is connected to the inlet end of an outlet pipe 33 that is connected to the outlet side connector 21 of the closed container 20 and through which the processed fluid F flows, while the space between the pair of gas permeable membranes 12 is the same. Are connected to each other by connecting pipes 32 connected to connectors 21, 21 provided in the closed containers 20, 20, respectively.

The present deaeration device 100 can be used as follows. Now, for example, consider the process of removing a specific dissolved gas from the fluid F supplied to the apparatus 100 through the inlet pipe 31. Fluid F supplied
First, when the gas enters the cylindrical gas permeable membrane 12 in the degassing section 91, the external space 22 of the gas permeable membrane 12 is exhausted by the exhaust device 40 to a negative pressure. Is drawn to the side of the gas permeable membrane 12 having a relatively lower partial pressure,
The gas dissolved in the gas permeable membrane 12 is further drawn to the side of the outer space 22 having a lower partial pressure, and finally discharged to the outer space 22 having the negative pressure.

As described above, the fluid F flowing through the cylindrical gas permeable membrane 12 of the degassing section 91 is continuously dissolved while the dissolved gas flows along the inner peripheral surface of the cylindrical gas permeable membrane 12. By the time the gas is removed and sent from the outlet opening 13 to the next inlet section 92, the dissolved gas concentration is already considerably low. As is clear from the above mechanism, the degree of reduction of the dissolved gas concentration varies depending on various parameters such as the degree of negative pressure, the flow rate of the fluid F, the length of the hollow cylindrical member 10 or the cylindrical gas permeable membrane 12, and the like. As will be seen from the experimental examples described later, such a condition setting can be easily performed in terms of design, and a sufficient effect can be obtained without requiring a particularly difficult setting method.

As described above, the fluid F which has been subjected to the primary treatment by the deaeration section 91 in the present deaeration apparatus 100 first enters the intake section 92, where it undergoes the secondary treatment. Inlet unit 92
A gas other than the gas F to be removed from the fluid F is supplied to the space 22 in the closed container 20 by pressurization as a gas 52 for intake obtained from a gas source 51. Therefore, when viewed in terms of the partial pressure of the dissolved gas to be removed from the fluid F, the peripheral wall of the cylindrical gas permeable membrane 12 (although in this embodiment, the peripheral wall itself is made of a gas permeable membrane as described above) The partial pressure in the external space 22 opposed to the air inlet is low, and as a result, the fluid F flowing into the gas permeable membrane 12 in the air inlet 92 is
The dissolved gas comes out to the outer space 22 of the gas permeable membrane 12 through the same process as in the degassing section 91.
Therefore, the inlet process of the inlet gas 52 in the inlet section 92 is of a type different from the inlet gas 52 and the fluid F
From the viewpoint of the dissolved gas to be degassed, the degassing process is also performed.

More specifically, in the deaeration apparatus 100 of the present invention, not only the dissolved gas to be finally removed in the first-stage deaeration section 91 but also all kinds of dissolved gases Is degassed from inside the fluid F, and then the fluid F
By the gas 52 which may be dissolved therein, the gas which is not desired to be dissolved is replacedly removed.

Therefore, this degassing device can be used for two-stage effective degassing of a gas that is not desired to be finally dissolved, as described above, and is a gas inlet device that only dissolves a desired gas. Can also be used as That is, firstly, as a primary treatment, the dissolved gas is extracted from the fluid F regardless of the type by the deaeration unit 91, and any type of gas is kept in a sufficiently low concentration state. If the desired gas 52 stored in the gas source 51 is pressurized and supplied into the internal space of the closed vessel 20 under operation of the gas pumping device 50, the gas 52 has a lower partial pressure for the gas. In order to move, it dissolves in the peripheral wall of the cylindrical gas permeable membrane 12, and then moves toward the fluid F having a lower partial pressure.
As a result, the intended intake gas 52 can be effectively dissolved in the fluid F. Particularly desirably, according to the apparatus 100 of the present invention, the concentration of the gas dissolved in the fluid F is considerably reduced by the primary treatment described above.
When a desired gas is dissolved in the inlet section 92, the fluid F is in a state in which the gas is easily dissolved. Therefore, the air intake processing time can be greatly reduced, or
It is not necessary to increase the size of the device configuration.

In view of the above, the positional relationship between the deaerator 91 and the inlet 92 is such that the deaerator 91 is provided upstream of the fluid flow path as shown in FIG. It can be seen that it is desirable to arrange the air inlet 92 on the downstream side. However, this is not a limitation, and the air inlet 92 may be provided on the upstream side due to the arrangement of the apparatus or when, for example, it is desired to make the deaerator 91 smaller. Also, the removal of dissolved gas from the fluid F or the entry of the desired gas 52 into the fluid F in the inlet section 92 can be achieved by dissolving the gas into the closed vessel 20 at a negative pressure, As long as this relationship is satisfied, the internal space 22 (in the gas permeable membrane 12) in the closed container 20 filled with the inlet gas 52 is generated as long as this relationship is satisfied. In some cases, the absolute pressure value of the outer space 22) may be the same as that of the outside of the closed container (for example, the inside and outside may be 1 atm). Further, in order to not always lower the purity of the gas 52 for air supply supplied into the closed container 20, an exhaust port (not shown) is provided in the closed container 20 in the inlet section 92, and the gas pressure feeding device 50 or the gas cylinder 54 is provided. It is also possible to adopt a configuration in which the intake gas 52 supplied from the container always passes through the inside of the closed container and exits from the exhaust port.

Here, a specific example of an experiment conducted to obtain pure water with a small amount of dissolved oxygen using the apparatus 100 of the embodiment shown in FIG. 1 will be described. An example of the device configuration is as shown in FIG.
Output water W _O having a concentration of 8.3 MΩ and an organic concentration of 5 ppb or less was flowed into the deaeration apparatus 100 by the pump 62 at a flow rate of 1 liter / minute. The pure manufacturing equipment 61 used was 0.07 pp for alkali metals such as sodium.
b and other metals can be removed down to 0.1 ppb or less. The gas permeable membrane 12 used as the hollow cylindrical member 10 in the deaeration section 91 and the air inlet section 92 of the present apparatus 100 was manufactured by ERC Co., Ltd.
RC301601, commercially available, with an inner diameter of about 1c
m, length is about 10m. Therefore, this gas permeable membrane 1
There is no doubt that 2 has a hollow cylindrical shape, but it is a long tube or hose in terms of the five senses, and this was stretched straight and housed in a closed container 20. Instead, it was bent and wound into a closed pipe 20 made of vinyl chloride, about 1 m in length. of course,
In principle, there is no restriction on the material of the closed container.

In this state, at an ambient environment temperature of 20 ° C., the inside of the airtight container 20 is first evacuated to several tens of Torr by the emblem pump used as the exhaust pump 41 in the degassing section 91.
When a saturated amount of 8.1 ppm of oxygen was dissolved in the output water W _O of the pure water generator and flowed under the above flow rate conditions, the dissolved oxygen amount was already reduced to 1.2 ppm at the output portion of the deaeration unit 91. Next, in the inlet section 92, a high-purity argon gas cylinder 54, which also serves as the gas pumping device 50 and the gas source 51, is supplied at a gauge pressure of 1 atm via a regulator not shown in FIG.
High-purity argon gas was pressurized and filled in 20. As a result, the dissolved oxygen concentration in the treated pure water Wp output from the deaeration device 100 was reduced to 50 ppb or less as measured by a dissolved oxygen meter.

Further, in order to verify the effect of reducing the dissolved oxygen concentration, a silicon substrate having an oxide film on the (111) surface was etched with a hydrofluoric acid solution, and hydrogen termination after removing the oxide film was attempted. In this reaction, since the amount of organic matter in the pure water Wp is also involved, it was also confirmed in advance that the quality of the pure water Wp did not deteriorate due to the use of the deaeration device 100. Was washed. The hydrofluoric acid used was of EL grade.

Conventionally, the silicon surface is immediately oxidized by dissolved oxygen contained in pure water used before and after such treatment, and hydrogen termination cannot be realized, or at least rarely. However, when a series of chemical treatments for hydrogen termination was performed using the pure water Wp treated by the deaeration device 100, hydrogen termination, which is the inferior reaction process, was not rejected by the predominant oxidation reaction. It was confirmed that it could be realized. That is, the hydrogen-terminated silicon substrate was placed in an ultra-vacuum chamber, preheated at about 100 ° C. for half a day, and then a high-speed electron diffraction pattern was observed. FIG. 3 (A) shows a faithful drawing of this diffraction pattern, and a so-called “1 × 1 structure” appears in response to the fact that the hydrogen termination has been reliably performed.
When heated to 50 ° C., a so-called “2 × 1 structure” was observed, as shown in FIG. In other words, the distance a between adjacent diffraction points in FIG. 3A is half of a / 2 in FIG.
This indicates that hydrogen was released. Thereafter, the silicon substrate was heated to 800 ° C., and it was confirmed that no carbides or the like were formed on the silicon substrate.

As can be understood from such experimental examples,
The practical effect of using the deaeration device 100 of the present invention is extremely large. Although the number of processing stages is multi-stage, unnecessary and efficient dissolution from the fluid can be achieved to a sufficient degree with a minimum two-stage configuration with only one stage for degassing and one stage for air intake. Since the gas can be removed, the device is considerably smaller. Therefore, the present deaeration device 100 can be incorporated into the existing piping system of the fluid F with a slight modification, and large and immovable high-cost equipment as recognized in the conventional vacuum deaeration method is required. High versatility is obtained, which is incomparable to the one. Even if the deaeration unit 91 and the intake unit 92 are arranged in a cascade from the upstream side to the downstream side of the fluid flow path of the fluid F, the separation distance is arbitrary, and the device Other members that do not impair the effect of 100 may be interposed. Of course, as described above, the fluid F to be treated is not limited to pure water or water as in the above experimental example, but can be developed into any kind of fluid (solution or solvent). From the viewpoint of the mechanism of displacing dissolved oxygen by mixing gas, conversely, the present invention apparatus 100 can be used as an apparatus for efficiently and effectively entering any gas 52 desired to be dissolved in a fluid, not limited to argon gas. it can.

In particular, as can be seen in the embodiment of FIG. 1 described above, when both the degassing section 91 and the gas inlet section 92 have a structure using the gas permeable membrane 12, the fluid When the present apparatus 100 is interposed in the middle of the flow path of F, there is also an advantage that a predetermined gas can be continuously degassed or inhaled without impairing the flow of the fluid F. There is no obstruction factor to the fluid flow in the deaeration section 91, and there is no obstruction factor in the intake section 92. This is because, in the air inlet principle of the air inlet unit 92 having the above-described configuration, the gas having a saturation amount or more does not dissolve in the fluid F, and bubbles are not generated and the fluid flow is not impaired. Therefore, the device 100 of the present embodiment is significantly superior to the deaeration or air inlet method using only the conventional bubbling device, and further, the tank becomes so large that the efficiency of the conventional bubbling method is increased. Although it is necessary to increase the size and to collect a large amount of intake gas that leaks with this, the device 100 of the present embodiment does not need to collect the gas, and therefore, for example, it may leak into the atmospheric environment such as hydrogen or ozone. When dealing with unwanted gases,
The deaeration device 100 of the present embodiment can be suitably used,
Excellent results can also be obtained in environmental aspects.

Although the preferred embodiments of the present invention have been described in detail above, modifications in accordance with the gist of the present invention are optional.
For example, in each of the above-described embodiments, the hollow tubular member 10 itself is constituted by the tubular (tube-like or hose-like) gas permeable membrane 12, but instead, the hollow tubular member 10 is provided between the inlet opening 11 and the outlet opening 13. A hollow cylindrical member 10 made of a rigid gas-impermeable material is used for a peripheral wall portion along which the fluid F flows along the inner surface thereof, so as to cover a window opened in at least a part of the peripheral wall. Alternatively, a sheet-like gas permeable membrane 12 may be provided. However, if the gas permeable membrane 12 is required to be quite long in order to increase the gas deaeration efficiency, it has flexibility in itself, as in the above-mentioned product example, It is desirable to use one that can be bent or twisted because the size of the device housing can be reduced. Of course, the expression cylindrical is not limited to a circular cross section. It may have a rectangular cross section or another hollow space.
In short, it is sufficient that the fluid F can flow inside (although it is desirable that the fluid F flows smoothly).

If the deaerator 91 and the inlet 92 are provided one by one, the essential constitution of the present invention is satisfied. That is, the device of the present invention is a device in which one deaerator 91 and one air inlet 92 constitute one unit. Therefore, for example, an apparatus in which one unit is constituted by these three parts in the order of the deaeration unit 91, the intake unit 92, and the deaeration unit 91 is naturally out of the scope of the present invention.

[0031]

According to the present invention, as a device for removing a predetermined gas from a fluid, or conversely, a desired gas is introduced,
A device is provided which is simple, compact, inexpensive, versatile in installation, and has a sufficient air-in / out effect. In view of the situation in the past where there was only a huge vacuum degassing facility or a bubbling device that was large and easy to install and had little flexibility, a degassing device that performs a two-stage cascade treatment of degassing according to the present invention is various types. It will be a great gospel for the industrial field.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of an embodiment of a deaeration apparatus configured according to the present invention.

FIG. 2 is an explanatory diagram of an example of a device configuration in a case where a device for reducing the amount of dissolved oxygen in pure water is configured using the degassing device of the present invention.

3 is an explanatory diagram faithfully depicting a high-speed electron diffraction pattern taken to see the effect of hydrogen termination treatment on a silicon surface using pure water treated by the apparatus configuration example shown in FIG. 2; .

[Explanation of symbols]

 10 hollow cylindrical member, 11 inlet opening, 12 gas permeable membrane, 13 outlet opening, 20 closed vessel, 22 gas permeable membrane outer space or closed vessel inner space, 31 inlet pipe, 32 connection pipe, 33 outlet pipe, 40 exhaust device , 50 gas pumping device, 51 gas source, 52 inlet gas, 53 compressor, 54 gas cylinder, 91 deaeration section, 92 intake section, 100 deaeration apparatus of the present invention.

Claims (4)

(57) [Claims] The present invention is characterized in that it is constituted by only one deaeration part and one air intake part; two parts in the middle of a fluid flow path through which a fluid flows are formed by partially or entirely forming a gas permeable membrane. The outer space of one of the gas permeable membranes is made a negative pressure to serve as the deaeration section,
The outside space of the other gas permeable membrane is made a positive pressure filled with a predetermined gas to serve as the above-mentioned inlet section; 2. The apparatus according to claim 1, wherein the external space of the one gas permeable membrane in the degassing section is an internal space of a closed container that houses the gas permeable membrane.
While the internal space of the closed container is exhausted by the exhaust device, the external space of the one gas permeable membrane is made to have the negative pressure; and the outside of the other gas permeable membrane in the air inlet. The space is also the internal space of the second closed container that contains the gas permeable membrane, and the gas supplied by the gas pumping device connected to the second closed container is filled in the internal space of the second closed container. Whereby the external space of the other gas permeable membrane is brought to the positive pressure. 3. The apparatus according to claim 1, wherein the gas permeable membrane has an inlet opening through which the fluid flows, an outlet opening through which the fluid flows out, and the inlet opening through which the fluid flows. A part of the peripheral wall of a hollow cylindrical member having a peripheral wall flowing along the inner surface from the outlet opening toward the outlet opening. 4. The apparatus according to claim 1, wherein the gas permeable membrane has an inlet opening through which the fluid flows in, an outlet opening through which the fluid flows out, and the inlet opening through which the fluid flows. A hollow cylindrical member having a peripheral wall that flows along the inner surface from the outlet opening toward the outlet opening.