JPS6250162B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for removing dissolved gases.

Conventionally, air and various gases have been dissolved in hydraulic oil, water, blood, artificial blood, and other various liquids.
The presence of this dissolved gas has caused extremely troublesome troubles in various fields. For example, in the field of mechanical engineering, cavitation tends to occur, shortening the life of hydraulic equipment and hydraulic equipment, generating noise, and even increasing the compression ratio if dissolved gas exists in the liquid. , the responsiveness or positioning accuracy was significantly impaired. Furthermore, in the field of chemical industry, it is often undesirable for gases to be mixed into liquids when chemical reactions are utilized. Furthermore, in the medical field, the dissolution of gas in blood or artificial blood is a problem that can be life-threatening.

Conventionally, the dissolved gas in the liquid was heated to expel the dissolved gas, but this method had drawbacks such as alteration and deterioration of the liquid.

Further, when the stirring blade a is rotated at high speed as shown in FIG. 7, cavitation lumps b each having a large volume are generated on the back surface thereof as shown by broken lines. A method is also known in which dissolved gas in a liquid that comes into contact with the surface of a large cavitation lump b that adheres to the stirring blade a is collected in the cavitation lump b for degassing. However, the method shown in FIG. 7 has the disadvantage that the total surface area of the cavitation mass b is extremely small, and the efficiency of collecting the dissolved gas through it is poor. Moreover, since the absolute value of the negative pressure of such a cavitation lump b was not very large and the pressure fluctuations (pulsations) were also relatively small, the removal efficiency of dissolved gas was even worse.

Furthermore, although it is widely known that the piston d in the cylinder c is extended to create a vacuum in the cylinder chamber e as shown in FIG. 8, the area of the contact surface g between the liquid and the vacuum part f is Since the pressure was extremely small and there was no pressure fluctuation (pulsation), the removal efficiency of dissolved gas was poor.

The present invention aims to eliminate these conventional drawbacks and to reliably remove (deaeration) a large amount of dissolved gas in a short period of time.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

In FIGS. 1 to 4, 1 is a cylinder barrel, and a piston 2 is slidably fitted inside the cylinder barrel 1, and is slid by a piston rod 3.
A cavitation chamber 4 that can be expanded and contracted is formed. Further, in the vicinity of the bottom wall 5 of the cylinder barrel 1, a large number of small-diameter orifice-shaped suction holes 6 are opened, and a suction pipe 7 is connected through these many suction holes 6. There is. Further, the suction pipe 7 is provided with a valve 8 that allows flow only in the suction direction shown by arrow A.

Reference numeral 9 denotes a discharge hole opened at an upper position near the bottom wall 5 of the cylinder barrel 1, and an upwardly extending discharge pipe 10 is connected in communication with the cavitation chamber 4. The middle part of this discharge pipe 10 is bent into an inverted U-shape as shown in FIG. 4 to form a gas storage part 11.
A gas discharge pipe 12 is connected to this storage section 11 . Furthermore, a valve 1 that only allows flow in the direction of arrow B
3 is interposed in the middle of the discharge pipe 10, and the piston 2 moves to the first position at a predetermined expansion speed E and contraction speed F.
If you slide as shown in the diagram → Figure 2 → Figure 3 → Figure 4,
Both valves 8 and 13 open and close as shown, and liquid flows into the cavitation chamber 4 through the suction hole 6 and flows out through the discharge hole 9.

Figure 5 shows the relationship between the pressure P at the jet location in the cavitation chamber 4 on the vertical axis and the stroke S of the piston 2 on the horizontal axis.If the expansion speed E is constant, then Since the expansion rate immediately after the start of the stroke is large, the absolute value of the negative pressure P becomes large, and pressure pulsations occur, resulting in a pressure curve as shown in this figure. Note that the stroke speed E
It is also possible to increase the negative pressure according to the stroke S to keep the negative pressure approximately constant. It is clear from this figure that the pressure pulsation is rapid.

In order to remove dissolved gas in the liquid using the device having the above-mentioned configuration, the piston 2 is slid at a predetermined expansion speed E as shown in FIGS. 1 to 2, and the cavitation chamber 4 is opened. When expanded, the gas-dissolved liquid flowing from the suction pipe 7 in the direction of arrow A flows into the cavitation chamber 4 in the form of a jet in a state of stronger turbulent mixing than the suction pores 6. . At this time, many local pulsating negative pressure parts are generated whose absolute value is much larger than the overall atmospheric pressure obtained by the expansion operation of the cavitation chamber 4 (see FIG. 5). As a result, initial cavitation consisting of countless microscopic bubbles is generated using the gas dissolved in the liquid as a core, thereby performing the first stage of deaeration.

In FIG. 1 or 2, it is these countless microscopic bubbles that are drawn like smoke from the vicinity of the suction pore 6. More specifically, the suction pore 6
At a number of local negative pressure sections within the jet from
When the vapor pressure falls below the saturated vapor pressure, the dissolved gas becomes the nucleus,
Microscopic bubbles are generated.

Next, while absorbing dissolved gas from the liquid in contact with the surface of the microscopic bubbles generated in the initial cavitation, larger microbubbles 15...
...and perform the second stage of deaeration. At this time, the microscopic bubbles serving as the nucleus vibrate violently in the jet stream, so they easily absorb dissolved gas from their surface and grow into microbubbles 15 in a short period of time.
Furthermore, the smaller the bubble, the larger the contact area with the liquid per unit volume, so it absorbs dissolved gas more efficiently, grows into microbubbles 15 in a shorter time, and dissolves in the liquid. The gas that had been in the air is separated as microbubbles 15, and these many microbubbles 15 float and gather on the ceiling surface 16 of the cavitation chamber 4, as shown in FIG. 2, to form large bubbles 17. Therefore, as shown in Figures 3 and 4,
As the piston 2 slides in the opposite direction, if the contraction speed F is set to be sufficiently lower than the expansion speed E, during this time many microbubbles 15 float to the surface and become large bubbles 17. Can be assembled. Furthermore, if the contraction speed F is small, the pressure within the cavitation chamber 4 will not increase, and it is possible to prevent the separated gas from redissolving into the liquid. And the fourth
As shown in the figure, the air bubbles 17 pass through the discharge hole 9 by arrow B.
Since the gas flows out in this direction and is stored in the gas storage section 11, the gas can be released by opening the valve 18 of the gas release pipe 12. Note that the gas storage section 11 can also be formed by a storage container body attached to the middle part of the discharge pipe 10.

Next, FIG. 6 shows another embodiment, in which a large number of suction holes 6 are opened at one end of the cavitation chamber 4 having a relatively long constant volume, and liquid is sucked in with a predetermined passage pressure loss. As well as being inhaled from the pipe 7, the position is isolated from the suction pore 6,
For example, as shown in the figure, a liquid pump 20 continuously discharges liquid from a discharge hole 19 opened at the other end in the longitudinal direction to create a negative pressure atmosphere in the cavitation chamber 4. Since the jet flow flowing from the suction pores 6 is in a state of strong turbulent mixing, local pressure pulsations occur over the entire area, and the local pulsations have a much larger absolute value than the overall atmospheric pressure of the cavitation chamber 4. Negative pressure can be generated. When the vapor pressure falls below the saturated vapor pressure, the dissolved gas becomes a nucleus and is separated, producing initial cavitation consisting of countless microscopic bubbles, and in this process, the first stage of deaeration is performed. (In FIG. 6, this corresponds to the area drawn like smoke from the suction pore 6.) Moreover, the initial cavitation at this time occurs continuously.

Thereafter, due to the negative pressure having a large absolute value and its pulsation, the microscopic bubbles of the initial cavitation rapidly absorb dissolved gas from the surface and grow, becoming microbubbles 15. This is the second stage of degassing.

Then, as they move inside the long cavitation chamber 4 toward the discharge hole 19 side, the micro bubbles 15...
... The particles gradually rise to the surface and collect on the ceiling surface 16 of the cavitation chamber 4, forming large air bubbles 17. Therefore,
The gas may be removed to the outside through a gas discharge hole 21 provided in the ceiling surface 16 using a gas pump 22 .
Note that the discharge hole 19 is preferably located at a lower position in the cavitation chamber 4.

It goes without saying that the present invention can be modified in addition to the embodiments described above. Liquids include hydraulic oil, water,
It can be used as any chemical liquid, chemical reaction liquid, blood, artificial blood, etc. It can also be used as a gas, such as various gases,
Air or anything else is free. Since the saturated vapor pressure and bubble separation pressure change depending on the type of liquid and gas, the negative pressure value of the negative pressure atmosphere and the negative pressure value of the local negative pressure section may also be increased or decreased accordingly. That is, the cross-sectional area and number of the suction pores 6 are increased or decreased depending on the type of liquid or gas, and the expansion speed E of the cavitation chamber 4 or the liquid pump 2 is adjusted.
What is necessary is to increase or decrease the discharge amount of 0. Alternatively, the cylinder barrel 1 may be of a vertical type, or the cavitation chamber 4 shown in FIG. It is also possible to use a device such as one provided at the lower end.

In the embodiment of the present invention shown in FIGS. 1 to 4 described above, a large negative pressure can be easily obtained, the entire device is simple, and the expansion rate E of the cavitation chamber 4 and the suction pore 6... If the number, shape, and cross-sectional area of ... are changed in accordance with the type of liquid and dissolved gas so that cavitation 14 is most likely to occur, dissolved gas can be separated with high efficiency.
Moreover, from the suction hole 6, a violently turbulent jet flow flows into the cavitation chamber 4, which tends to cause initial cavitation, and the minute bubbles and micro bubbles 15 are pulsating and have a very large contact with a unit volume. Because it has a large surface area, it can separate gases with high efficiency in a short period of time. Moreover, if the number of suction holes 6 is increased to make the microbubbles sufficiently small, the surface area per unit volume can be further increased and the pulsation can be increased. Furthermore, as shown in FIG. 5, intense pressure pulsations in the jet section generate local negative pressure with an absolute value much larger than the overall negative pressure, promoting gas separation.

Further, in the embodiment described in FIG. 6, dissolved gas can be removed continuously and with high efficiency by constantly maintaining an optimum cavitation state. Incidentally, by installing the pump 20 at a low location, it is possible to prevent the pump 20 itself from generating cavitation.

As detailed above, the dissolved gas removal method of the present invention is structured, and the initial cavitation of the first stage of degassing is made up of countless microscopic bubbles and has pressure fluctuations (negative pressure) that vibrate violently, resulting in strong turbulence. Since the flow is in a mixed jetting state and the total surface area in contact with the liquid is very large, the subsequent growth rate into microbubbles 15 and large bubbles 17 is very high, which is different from the conventional method shown in Figures 7 and 8. Compared to the previous dissolved gas removal method, we were able to achieve deaeration efficiency several hundred times higher.

That is, in the present invention, (a) the smaller the cavitation bubbles, the larger the total surface area and the faster the absorption rate of dissolved gas, and (b) the larger the absolute value of the negative pressure, the larger the absolute value of the negative pressure. We cleverly utilize the following three points: (3) The larger the flow rate and the more pulsating, the higher the separation speed of the dissolved gas. (c) If the jet is in the form of a jet and is in a strongly turbulent mixing state, the separation speed of the dissolved gas is higher. With this method, we were able to achieve highly efficient degassing that was dramatically superior to conventional methods.

[Brief explanation of the drawing]

Figures 1 to 4 are operation process diagrams for sequentially explaining an embodiment of the first invention, Figure 5 is a pressure curve diagram, and Figure 6 is an operating state showing an embodiment of the second invention. 7 is a plan view of a main part showing a conventional stirring type degassing method, and FIG. 8 is a sectional front view of a main part showing a conventional cylinder type vacuum generation method. 4... cavitation chamber, 6... suction pore,
9... Discharge hole, 13... Valve, 15... Micro bubble,
16...Ceiling surface, 17...Air bubble, 20...Liquid pump, 21...Gas discharge hole, 22...Gas pump.

Claims (1)

[Scope of Claims] 1. A cavitation chamber having a large number of suction pores is expanded at a predetermined expansion speed, and liquid is sucked in a jet form through the suction pores in a state of strong turbulent mixing. The operation generates many local pulsating negative pressure parts whose absolute value is much larger than the overall atmospheric pressure of the cavitation chamber, and the gas dissolved in the liquid is used as a nucleus to form countless microscopic bubbles. The first stage of degassing is performed by generating initial cavitation, and then the microbubbles generated in the initial cavitation grow into larger microbubbles while absorbing dissolved gas from the liquid in contact with the surface of the microbubbles. The microbubbles are floated and collected above the cavitation chamber to form large air bubbles, and then the cavitation chamber is contracted and the microbubbles are discharged from the discharge hole having a valve. A method for removing dissolved gas characterized by discharging air bubbles. 2 While a liquid pump continuously discharges liquid from the discharge hole of a constant volume cavitation chamber, the liquid is jetted in a state of strong turbulent mixing from a large number of suction pores located separately from the discharge hole. It generates a large number of local pulsating negative pressure parts whose absolute value is much larger than the overall atmospheric pressure of the cavitation chamber obtained by the inhalation and exhalation, and the gas dissolved in the liquid is used as the core to generate countless microscopic particles. The first stage of deaeration is performed by generating initial cavitation consisting of small air bubbles, and then, while absorbing dissolved gas from the liquid in contact with the surface of the microscopic bubbles generated in the initial cavitation, larger microbubbles are generated. The microbubbles are grown into bubbles and then degassed in the second stage, and the microbubbles are floated and aggregated on the ceiling of the cavitation chamber to form large bubbles, which are then sent to the gas pump through the gas discharge hole provided in the ceiling. A method for removing dissolved gas, characterized in that the dissolved gas is removed to the outside.