JP2024137124A - Foam reduction device - Google Patents

Abstract

To provide a bubble reduction device that can control bubbles from overflowing from such as a tank that is installed in a plant at low cost.SOLUTION: A bubble reduction device 1 that can be used for reducing bubbles contained in liquid includes: a self-suction type centrifugal pump 9 capable of separating a gas-liquid mixture into a liquid and a gas by centrifugation in a discharge passage part 18; and a first exhaust part 10 for naturally evacuating the gas separated by centrifugation.SELECTED DRAWING: Figure 3

Description

The present invention relates to a foam reduction device that can be used to reduce foam contained in a liquid.

Conventionally, pump devices capable of centrifuging a gas-liquid mixture in which gas has been mixed into a liquid are known. For example, the pump device disclosed in Patent Document 1 includes a pump for gas-liquid centrifugation and a vacuum device connected to the pump. The gas centrifuged in the pump is then exhausted using the vacuum device.

Patent No. 3924730

For example, the coolant used in machine tools in factories is stored in a tank in the factory, but bubbles that form in the coolant inside the tank can sometimes overflow from the tank. To deal with this, it is possible to use a pump device such as that described in Patent Document 1 to deal with the bubbles inside the tank. However, this pump device is equipped with an expensive vacuum device, which creates the problem of high costs.

The present invention was made in consideration of these points, and its purpose is to provide a low-cost foam reduction device that can prevent foam from overflowing from a tank installed in, for example, a factory.

To achieve the above objective, the present invention is characterized by using a self-priming centrifugal pump to naturally exhaust the centrifuged gas.

Specifically, the research focused on a foam reduction device that can be used to reduce bubbles contained in liquids, and the following solutions were implemented:

That is, in the first invention, a self-priming centrifugal pump is provided with an impeller housed in a casing, a suction port provided on the rotation axis of the impeller in the casing and for introducing a gas-liquid mixture into the casing, a large volute chamber and a small volute chamber provided around the impeller, a discharge pipe section connected to the large volute chamber, and a first cavity receiving section capable of receiving from the upstream side a tornado-shaped cavity generated in the discharge pipe section by ejecting the gas-liquid mixture from an ejection path connected to the small volute chamber into the discharge pipe section, and further comprising an exhaust section for naturally exhausting the gas that forms the tornado-shaped cavity.

The second invention is characterized in that, in the first invention, a second cavity receiving portion capable of receiving the tornado-shaped cavity from the downstream side is provided, and the exhaust portion is configured to naturally exhaust the gas forming the tornado-shaped cavity received in the second cavity receiving portion.

The third invention is characterized in that, in the second invention, the second cavity receiving portion is umbrella-shaped and has an umbrella-shaped portion capable of receiving the tornado-shaped cavity from the downstream side, and the exhaust portion has a first exhaust passage portion connected to the inside of the umbrella-shaped portion.

The fourth invention is characterized in that, in the second invention, the second hollow receiving portion includes a blocking portion that blocks the downstream end of the discharge pipe portion and a through hole portion formed through the center portion of the blocking portion, and the exhaust portion includes a second exhaust passage portion that is connected to the discharge pipe portion via the through hole portion or by being inserted into the through hole portion.

The fifth invention is characterized in that, in the second invention, the second cavity receiving portion is connected to the downstream end of the discharge pipe portion and has a tapered pipe portion configured to reduce in diameter as it goes downstream, and the exhaust portion is connected to the downstream end of the tapered pipe portion.

The sixth invention is any one of the first to fifth inventions, characterized in that the discharge pipe section is provided with a discharge port that opens in a tangential direction to the inner wall surface of the discharge pipe section.

The seventh invention is the sixth invention, characterized in that the part of the discharge pipe where the discharge port is provided has a larger inner diameter than the part upstream of that part.

The eighth invention is characterized in that, in the first invention, the exhaust section includes another discharge pipe section arranged around the discharge pipe section, and a connecting pipe section having one end connected to the discharge pipe section and the other end connected to the other discharge pipe section in a tangential direction to its inner wall surface, the exhaust section includes an inlet port for introducing the gas in the other discharge pipe section into the exhaust section, and the inlet port is located downstream of the part of the other discharge pipe section to which the connecting pipe section is connected and in the inner peripheral region of the other discharge pipe section.

In the first invention, when the gas-liquid mixture is introduced into the casing from the suction port by the rotation of the impeller, the gas-liquid mixture is ejected through the small volute chamber and the ejection path so as to generate a vortex in the discharge pipe section. When a vortex is generated in the discharge pipe section, the gas-liquid mixture is centrifuged into liquid and gas, and a tornado-shaped cavity is generated in the inner peripheral region of the discharge pipe section. The tornado-shaped cavity is received from the upstream side by the first cavity receiving section, so that after extending toward the downstream side, it is naturally exhausted from the exhaust section without using a vacuum device. This makes it possible to reduce bubbles contained in the gas-liquid mixture while suppressing the increase in cost due to the vacuum device. Therefore, for example, by using a bubble reduction device, it is possible to reduce bubbles contained in the coolant liquid used in the machine tool, so that it is possible to prevent bubbles from overflowing from a tank in which the coolant liquid is stored in a factory.

In the second invention, the tornado-shaped cavity that is generated to extend downstream by being received from the upstream side by the first cavity receiving section is received from the downstream side by the second cavity receiving section. The tornado-shaped cavity received in the second cavity receiving section, i.e., the gas, is then exhausted from the exhaust section. This allows the gas that has been centrifuged from the gas-liquid mixture to be smoothly exhausted.

In the third invention, when the tornado-shaped cavity reaches the umbrella-shaped portion, it is introduced into the interior of the umbrella-shaped portion. The introduced tornado-shaped cavity, i.e., the gas, is exhausted from the first exhaust passage portion connected to the interior of the umbrella-shaped portion. This allows the gas separated by centrifugal force from the gas-liquid mixture to be properly exhausted.

In the fourth invention, the tornado-shaped cavity generated in the inner peripheral region of the discharge pipe section is received by the blocking section. The tornado-shaped cavity received in the blocking section, i.e., the gas, is then exhausted from the second exhaust passage section. This allows the gas separated by centrifugal force from the gas-liquid mixture to be properly exhausted.

In the fifth invention, when the tornado-shaped cavity passes through the tapered tube section connected to the downstream end of the discharge tube section, it hits the inner surface of the tapered tube section, which narrows in diameter as it goes downstream, that is, it is received by the inner surface of the tapered tube section and is guided to the inner circumference side of the tapered tube section. The gas that forms the tornado-shaped cavity and is guided to the inner circumference side is properly exhausted from the exhaust section connected to the downstream end of the tapered tube section. This makes it possible to prevent liquid from being discharged from the exhaust section mixed with the gas.

In the sixth invention, when the gas-liquid mixture is centrifuged to separate the gas and liquid, a tornado-shaped cavity is generated on the inner periphery of the discharge pipe section by centrifugal force, while a swirling flow of liquid is generated on the outer periphery of the discharge pipe section. Because the discharge port opens tangentially to the inner wall surface of the discharge pipe section, the liquid swirling on the outer periphery of the discharge pipe section is easily discharged from the discharge port, while the tornado-shaped cavity on the inner periphery of the discharge pipe section, i.e., the gas, is difficult to discharge from the discharge port. This allows the liquid to be appropriately discharged from the discharge port.

In the seventh invention, when the discharge port is provided so as to open in a tangential direction to the inner wall surface of the discharge pipe section, the smaller the inner diameter of the discharge pipe section, the smaller the opening area of the discharge port provided in the discharge pipe section, but the inner diameter of the part of the discharge pipe section where the discharge port is provided is larger than the part upstream of that part. This increases the opening area of the discharge port, thereby suppressing the pressure loss of the liquid discharged from the discharge port.

In the eighth invention, a gas-liquid mixture is discharged from the connecting pipe section to another discharge pipe section, which generates a vortex in the other discharge pipe section. Then, a tornado-shaped cavity is generated in the inner peripheral region of the other discharge pipe section by centrifugal separation caused by the vortex, and the gas that forms the tornado-shaped cavity is introduced from the inlet into the exhaust section and exhausted, so that the centrifuged gas can be appropriately exhausted.

1 is a schematic diagram showing a factory equipped with a bubble reduction device according to a first embodiment of the present invention; FIG. 1 is a partial cross-sectional view showing a bubble reduction device according to a first embodiment of the present invention. 1 is a schematic cross-sectional view showing a bubble reduction device according to a first embodiment of the present invention. FIG. FIG. 4 is a schematic end view taken along line IV-IV in FIG. A schematic cross-sectional view showing a bubble reduction device according to a second embodiment of the present invention. 6 is a schematic end view taken along line VI-VI in FIG. 5. A schematic cross-sectional view showing a bubble reduction device according to a third embodiment of the present invention. A partial cross-sectional view showing a bubble reduction device according to a fourth embodiment of the present invention. A schematic cross-sectional view showing a bubble reduction device according to a fourth embodiment of the present invention. 9 is a schematic cross-sectional view taken along line XX in FIG. 8. A schematic cross-sectional view showing a bubble reduction device according to a modified example of the present invention.

The following describes in detail an embodiment of the present invention with reference to the drawings. Note that the following description of the preferred embodiment is essentially merely exemplary.

First embodiment of the present invention
FIG. 1 shows a factory P (e.g. a machining factory) equipped with a bubble reduction device 1 according to a first embodiment of the present invention.

The factory P is equipped with a bubble reduction device 1, a tank 2, a machine tool 3, and a liquid pump 7. The bubble reduction device 1 is connected to a suction pipe 4, a liquid discharge pipe 5, and a gas discharge pipe 6. A gas-liquid mixture containing a liquid (coolant liquid) and a gas (bubbles) stored in a tank 2 is introduced into the bubble reduction device 1 through the suction pipe 4. The introduced gas-liquid mixture is centrifuged into liquid and gas in the bubble reduction device 1, and the centrifuged liquid is discharged from the liquid discharge pipe 5 and returned to the tank 2. Meanwhile, the centrifuged gas is naturally exhausted from the gas discharge pipe 6. Here, since the factory P is not equipped with a vacuum device such as a vacuum pump, the centrifuged gas is naturally exhausted from the gas discharge pipe 6 without using a vacuum device.

The machine tool 3 is, for example, a machine capable of cutting metal materials, and is configured to perform the cutting process using liquid supplied from the liquid pump 7 via the liquid supply pipe 35. The liquid used for the cutting process in the machine tool 3 is returned to the tank 2 via the return pipe 8 after cutting chips and the like are removed by a filter (not shown). The liquid returned to the tank 2 is defoamed via the suction pipe 4, the defoamer 1, and the liquid discharge pipe 5, and is returned to the tank 2 again.

In addition, air bubbles (dispersed air bubbles) are generated in the tank 2 due to reasons such as dropping liquid from the return pipe 8 into the tank 2. The generated air bubbles become foam (surface bubbles) by rising close to the liquid surface, so that the tank 2 is in a state where liquid, air bubbles, and an air-liquid mixture containing the bubbles are stored. If the amount of foam increases, the foam will overflow from the tank 2, so in this embodiment, the foam reduction device 1 is used to reduce the amount of foam contained in the liquid in the tank 2.

Next, the bubble reduction device 1 according to the first embodiment will be described with reference to Figures 2 to 4.

As shown in FIG. 2, the bubble reduction device 1 includes a pump 9 and a first exhaust section 10.

The pump 9 is a self-priming centrifugal pump that has a rotating shaft 12 that is driven by an electric motor 11, and an impeller 13 is provided at the tip of the rotating shaft 12.

The impeller 13 is housed in a freely rotatable state inside the casing 14 of the pump 9. A suction port 15 is provided on the axis of rotation of the impeller 13 in the casing 14, i.e., on the extension of the rotating shaft 12. The suction pipe 4 is connected to the suction port 15, and the gas-liquid mixture from the tank 2 is introduced into the casing 14 via the suction pipe 4 and the suction port 15.

In addition, as shown in FIG. 3, a small volute chamber 16 and a large volute chamber 17 larger than the small volute chamber 16 are provided around the impeller 13 within the casing 14. In this embodiment, the impeller 13 is configured to rotate counterclockwise in FIG. 3.

The small volute chamber 16 is formed to extend upward, i.e., in the vertical direction, while the large volute chamber 17 is formed to extend approximately downward. Also, the portion 16a where the small volute chamber 16 begins in the casing 14 is set at a position below the suction port 15, while the portion 17a where the large volute chamber 17 begins in the casing 14 is set at a position above the suction port 15.

The gap between the portion 16a where the small volute chamber 16 begins and the outer periphery of the impeller 13 is larger than the gap between the portion 17a where the large volute chamber 17 begins and the outer periphery of the impeller 13. The large volute chamber 17 is connected to a discharge passage portion 18 provided in the casing 14.

The discharge passage 18 is configured to discharge liquid from the large volute chamber 17 by centrifugal force generated by the rotation of the impeller 13, and its upstream portion in the discharge direction extends along the small volute chamber 16. In addition, the downstream portion in the discharge direction of the discharge passage 18 extends upward, in other words, it has an upward cylindrical shape.

Furthermore, above the discharge path section 18, a first pipe section 19 and a second pipe section 20 are arranged in a posture in which the extension direction of the tube center line extends in the vertical direction. The downstream end in the discharge direction of the discharge path section 18, i.e., the upper end, is connected to the lower end of the first pipe section 19, and the upper end of the first pipe section 19 is connected to the lower end of the second pipe section 20. The upper end of the second pipe section 20 is connected to the liquid discharge pipe 5 (see FIG. 1), which is not shown in FIG. 3. In this embodiment, the upper part of the first pipe section 19 has a larger inner diameter than the lower part.

One end of the ejection path 21 is connected to the upper end of the small volute chamber 16. The ejection path 21 extends in a substantially horizontal direction and is then connected to the discharge path section 18 via an ejection port 22 provided at the other end. In this embodiment, the ejection port 22 opens tangentially to the inner wall surface of the discharge path section 18.

A hollow receiving portion 23 is provided in the discharge path portion 18 upstream of the ejection port 22 in the discharge direction, i.e., below the ejection port 22. The hollow receiving portion 23 is located in the inner peripheral region of the discharge path portion 18 and has a substantially T-shaped cross section.

The upper portion of the first pipe 19 is provided with a first exhaust section 10 and an umbrella-shaped section 10a. The first exhaust section 10 is connected to the inside of the umbrella-shaped section 10a, which is formed in an umbrella shape so that it is positioned radially outward as it goes downward, and is provided with a first exhaust passage section 10b that is provided to extend in a substantially horizontal direction, and a support section 10c (see Figures 3 and 4) that is provided to extend in a substantially horizontal direction on the opposite side of the umbrella-shaped section 10a from the first exhaust passage section 10b.

The umbrella-shaped portion 10a is provided at a position corresponding to the hollow receiving portion 23 in the vertical direction, and its upper end is located approximately in the center of the first pipe portion 19. The inner peripheral end of the first exhaust passage portion 10b is connected to the upper end of the umbrella-shaped portion 10a as shown in FIG. 3. On the other hand, the outer peripheral end of the first exhaust passage portion 10b protrudes radially outward from the outer peripheral surface of the first pipe portion 19 and is connected to the gas exhaust pipe 6 (see FIG. 1) not shown in FIG. 3.

Next, the function of the bubble reduction device 1 according to the first embodiment will be explained.

The pump 9 of the foam reduction device 1 is introduced with a gas-liquid mixture from the tank 2 via the suction pipe 4, so that gas and liquid are mixed inside the casing 14 both at startup and during normal operation. Below, we will explain the function of the pump 9 to introduce the gas-liquid mixture from the tank 2 into the casing 14, i.e., self-priming, even when gas is present inside at startup, and the function of reducing bubbles by discharging gas from the introduced gas-liquid mixture, i.e., foam reduction.

Before starting the pump 9, an appropriate amount of liquid or gas-liquid mixture (so-called "priming water") is supplied into the casing 14, resulting in a state in which gas and liquid or gas-liquid mixture are mixed inside the casing 14. When the electric motor 11 starts to rotate the impeller 13 in this state, the gap between the part 16a where the small volute chamber 16 begins in the casing 14 and the outer periphery of the impeller 13 is larger than the gap between the part 17a where the large volute chamber 17 begins in the casing 14 and the outer periphery of the impeller 13, so that a circulating flow is generated in which the liquid or gas-liquid mixture in the discharge passage portion 18 flows in the order of the large volute chamber 17, the impeller 13, the small volute chamber 16, the ejection passage 21, the ejection port 22, and the discharge passage portion 18. In addition, when a circulating flow is occurring, the gas in the central region of the impeller 13 is mixed with the liquid or gas-liquid mixture of the circulating flow by the vortex generated by the rotation of the impeller 13, and is ejected from the ejection port 22 into the discharge passage portion 18.

When the gas-liquid mixture is ejected from the ejection port 22 into the discharge path 18, the ejection port 22 is provided so as to open in a tangential direction to the inner wall surface of the discharge path 18, so that the gas-liquid mixture swirls within the discharge path 18 and is centrifuged into liquid and gas. The centrifuged liquid with a relatively large mass swirls on the outer periphery of the discharge path 18 due to centrifugal force, generating a swirling flow of liquid in the outer periphery region of the discharge path 18. On the other hand, the centrifuged gas with a relatively small mass generates a tornado-shaped cavity in the inner periphery region of the discharge path 18 due to centrifugal force.

The swirling flow of the liquid then becomes the circulating flow that flows upstream in the discharge direction through the discharge passage 18 and into the large volute chamber 17.

Meanwhile, the tornado-shaped cavity is received from below by the cavity receiving portion 23. As a result, the tornado-shaped cavity extends upward from the cavity receiving portion 23.

The tornado-shaped cavity extending upward is received from above by the umbrella-shaped portion 10a and introduced into the umbrella-shaped portion 10a. The gas in the umbrella-shaped portion 10a is then exhausted to the gas exhaust pipe 6 via the first exhaust passage portion 10b connected to the inside of the umbrella-shaped portion 10a.

As the gas present inside the casing 14 and the suction pipe 4 is exhausted from the gas exhaust pipe 6, the suction side of the casing 14 becomes negative pressure, and the gas-liquid mixture stored in the tank 2 is introduced into the casing 14 through the suction pipe 4. Of the gas-liquid mixture introduced into the casing 14, the gas-liquid mixture located near the outer periphery of the impeller 13, i.e., the gas-liquid mixture with high density and high liquid ratio, is discharged from the large volute chamber 17 to the discharge passage section 18 by the centrifugal force generated by the rotation of the impeller 13, and then passes through the first pipe section 19 and the second pipe section 20 in order, and is discharged into the liquid discharge pipe 5 connected to the second pipe section 20.

The self-priming function of pump 9 ends here, and the pump transitions to a function of reducing bubbles by expelling gas from the introduced gas-liquid mixture, i.e., a defoaming function.

The gas-liquid mixture introduced into the casing 14, which is located near the inner circumference of the impeller 13, i.e., has a low density and a high gas ratio, passes through the small volute chamber 16 and the ejection path 21, and is ejected from the ejection port 22 into the discharge path portion 18, whereby it is centrifuged into liquid and gas. The gas generated by this centrifugation, i.e., the tornado-shaped cavity, is received from below by the cavity receiving portion 23, extends upward, and is introduced into the umbrella-shaped portion 10a. The tornado-shaped cavity introduced into the umbrella-shaped portion 10a is exhausted to the gas exhaust pipe 6 through the first exhaust passage portion 10b. The gas exhaust pipe 6 exhausts the gas to the outside without using a vacuum device. Therefore, the air bubbles and foam contained in the liquid stored in the tank 2 are centrifuged with the liquid by the foam reduction device 1 according to the first embodiment, and are exhausted from the gas exhaust pipe 6. Therefore, it is possible to reduce the foam in the tank 2, and it is possible to prevent the foam from overflowing from the tank 2.

Meanwhile, the swirling flow of liquid passes through the outer peripheral region of the umbrella-shaped portion 10a in the first pipe portion 19 and flows into the second pipe portion 20. The swirling flow of liquid that has flowed into the second pipe portion 20 is then returned to the tank 2 via the liquid discharge pipe 5 connected to the second pipe portion 20. The defoamed liquid is sent to the machine tool 3 by the liquid delivery pump 7, and the used liquid is returned to the tank 2 via the return pipe 8.

As described above, in the first embodiment, when the gas-liquid mixture is introduced into the casing 14 from the suction port 15 by the impeller 13 rotating, a part of the gas-liquid mixture, particularly a gas-liquid mixture with a high ratio of gas, is ejected through the small volute chamber 16 and the ejection path 21 so as to generate a vortex in the discharge path section 18. When a vortex is generated in the discharge path section 18, the gas-liquid mixture is centrifuged into liquid and gas, and a tornado-shaped cavity is generated in the inner peripheral region of the discharge path section 18. The tornado-shaped cavity is received from below by the cavity receiving section 23, so that after extending upward, that is, toward the downstream side, it is naturally exhausted from the first exhaust section 10 without using a vacuum device. As a result, gas is exhausted without a vacuum device, so it is possible to reduce bubbles contained in the gas-liquid mixture while suppressing the increase in cost due to the vacuum device. Therefore, for example, by using the bubble reduction device 1, it is possible to reduce the amount of bubbles contained in the coolant liquid used in the machine tool 3, thereby preventing bubbles from overflowing from the tank 2 in which the coolant liquid is stored in the factory P.

The tornado-shaped cavity that is generated to extend upward (downstream) by being received from below (upstream) by the cavity receiving portion 23 is received from above (downstream) by the umbrella portion 10a. The tornado-shaped cavity received by the umbrella portion 10a, i.e., the gas, is then exhausted from the first exhaust passage portion 10b. This allows the gas that has been centrifuged from the gas-liquid mixture to be smoothly exhausted.

When the tornado-shaped cavity reaches the umbrella-shaped portion 10a, it is introduced into the umbrella-shaped portion 10a. The tornado-shaped cavity, i.e., the gas, is exhausted from the first exhaust passage portion 10b connected to the inside of the umbrella-shaped portion 10a. This allows the gas separated by centrifugal force from the gas-liquid mixture to be properly exhausted.

In the first embodiment, the first exhaust passage section 10b is connected to the upper end of the umbrella-shaped section 10a, but it is sufficient if it is connected to the inside of the umbrella-shaped section 10a, and it may be connected, for example, to a vertical midpoint of the umbrella-shaped section 10a.

Second embodiment of the present invention
Next, a second embodiment of the present invention will be described with reference to Figures 5 and 6. Note that a description of parts common to the first embodiment will be omitted, and only parts different from the first embodiment will be described.

The bubble reduction device 1 according to the first embodiment (see FIG. 3) is provided with a first pipe section 19 and a second pipe section 20, but the bubble reduction device 1 according to the second embodiment (see FIG. 5) is provided with a third pipe section 24, a fourth pipe section 25, and a fifth pipe section 26 instead of the first pipe section 19 and the second pipe section 20. In addition, the bubble reduction device 1 according to the first embodiment exhausts gas through the first exhaust section 10 (first exhaust passage section 10b) and the umbrella-shaped section 10a provided in the first pipe section 19, but the bubble reduction device 1 according to the second embodiment is configured to exhaust gas using the second exhaust section 27.

As shown in FIG. 5, the third pipe section 24 is disposed in such a manner that the extension direction of the tube centerline extends in the vertical direction, and is configured to expand in diameter as it goes upward. The third pipe section 24 has its lower end fixed to the upper end of the discharge passage section 18, while its upper end is fixed to the lower end of the fourth pipe section 25.

The fourth tube section 25 is disposed in such a manner that the extension direction of the tube centerline extends in the vertical direction, and a first liquid discharge path section 25a is provided to discharge the liquid in the fourth tube section 25. As shown in FIG. 6, the inner peripheral end of the first liquid discharge path section 25a is provided with a discharge port 25b that opens in a tangential direction to the inner wall surface of the fourth tube section 25. The outer peripheral end of the first liquid discharge path section 25a is connected to the liquid discharge pipe 5 (see FIG. 1), which is not shown in FIGS. 5 and 6. Here, the gas-liquid mixture is ejected from the ejection path 21 into the discharge path section 18, so that a swirling flow of liquid is generated in the outer peripheral region of the fourth tube section 25, and the liquid easily flows into the first liquid discharge path section 25a that is connected in a tangential direction to the inner wall surface of the fourth tube section 25 (see FIG. 6). On the other hand, a tornado-shaped cavity is generated in the inner peripheral region of the fourth pipe section 25, and a swirling flow of liquid exists on the outer peripheral side of the tornado-shaped cavity, making it difficult for the gas that forms the tornado-shaped cavity in the fourth pipe section 25 to be exhausted to the first liquid discharge path section 25a.

The lower end of the fifth tube 26 is fixed to the upper end of the fourth tube 25. The fifth tube 26 is disposed in such a position that the extension direction of its tube centerline extends in the vertical direction. A first cover 26a is attached to the upper end of the fifth tube 26 so as to close the opening of the upper end. A through hole 26b is formed in the center of the first cover 26a in the thickness direction.

The second exhaust section 27 includes a second exhaust passage section 27a. One end of the second exhaust passage section 27a is inserted into the through hole section 26b of the first cover section 26a, and is connected to the fifth pipe section 26. Meanwhile, the other end of the second exhaust passage section 27a is connected to the gas exhaust pipe 6.

Next, the function of the bubble reduction device 1 according to the second embodiment will be described.

By ejecting the gas-liquid mixture from the ejection port 22 into the discharge path 18, a tornado-shaped cavity is generated in the inner peripheral region of the discharge path 18, while a swirling flow of liquid is generated in the outer peripheral region of the discharge path 18.

The tornado-shaped cavity is generated so as to extend upward from the cavity receiving portion 23 through the inner peripheral regions of the discharge path portion 18, the third pipe portion 24, the fourth pipe portion 25, and the fifth pipe portion 26. The gas forming the tornado-shaped cavity is received by the first cover portion 26a, and then exhausted to the gas exhaust pipe 6 via the second exhaust passage portion 27a. As a result, air bubbles and foam contained in the liquid stored in the tank 2 are centrifuged with the liquid by the foam reduction device 1 according to the second embodiment, and are exhausted from the gas exhaust pipe 6 without using a vacuum device. Therefore, it is possible to reduce the amount of foam in the tank 2, and it is possible to prevent the foam from overflowing from the tank 2.

Meanwhile, the swirling flow of the liquid flows upward from the discharge path section 18 to the third pipe section 24 while swirling around each outer circumferential region, and is then discharged from the third pipe section 24 to the first liquid discharge path section 25a via the discharge port 25b. The liquid discharged to the first liquid discharge path section 25a is returned to the tank 2 via the liquid discharge pipe 5. The defoamed liquid is then sent to the machine tool 3 by the liquid feed pump 7, and the used liquid is returned to the tank 2 via the return pipe 8.

As described above, in the second embodiment, the tornado-shaped cavity generated in the inner peripheral region of the discharge path section 18, the third pipe section 24, the fourth pipe section 25, and the fifth pipe section 26 is received by the first cover section 26a. The tornado-shaped cavity received by the first cover section 26a, i.e., the gas, is then exhausted from the second exhaust passage section 27a. This allows the gas separated by centrifugal force from the gas-liquid mixture to be properly exhausted.

When the gas-liquid mixture is centrifuged into gas and liquid, a tornado-shaped cavity is generated on the inner periphery of the discharge path section 18 by centrifugal force, while a swirling flow of liquid is generated on the outer periphery of the discharge path section 18. Because the discharge port 25b opens tangentially to the inner wall surface of the fourth tube section 25, the liquid swirling on the outer periphery of the fourth tube section 25 is easily discharged from the discharge port 25b, while the tornado-shaped cavity on the inner periphery of the fourth tube section 25, i.e., the gas, is difficult to discharge from the discharge port 25b. This allows the liquid to be appropriately discharged from the discharge port 25b.

In addition, when the discharge port 25b is provided so as to open in a tangential direction to the inner wall surface of the fourth tube section 25, the smaller the inner diameter of the fourth tube section 25, the smaller the opening area of the discharge port 25b provided in the fourth tube section 25. However, the part of the fourth tube section 25 where the discharge port 25b is provided has a larger inner diameter than the part upstream in the discharge direction, i.e., the lower part. As a result, the opening area of the discharge port 25b is increased, thereby suppressing the pressure loss of the liquid discharged from the discharge port 25b.

In the bubble reduction device 1 according to the second embodiment, one end of the second exhaust passage section 27a is inserted into the through hole section 26b of the first cover section 26a to connect the second exhaust passage section 27a to the fifth pipe section 26, but the second exhaust passage section 27a may be connected to the fourth pipe section 25 via the through hole section 26b. Furthermore, in the bubble reduction device 1 according to the second embodiment, the discharge port 25b is provided in the fourth pipe section 25, but the discharge port 25b may be provided in the fifth pipe section 26.

In addition, in the bubble reduction device 1 according to the second embodiment, the discharge port 25b is provided so as to open in a tangential direction relative to the inner wall surface of the fourth tube section 25, but the discharge port 25b may also be provided so as to open along a tangential direction relative to the inner wall surface of the fourth tube section 25.

Third embodiment of the present invention
Next, a third embodiment of the present invention will be described with reference to Fig. 7. Note that a description of parts common to the second embodiment will be omitted, and only parts different from the second embodiment will be described.

The bubble reduction device 1 according to the second embodiment (see FIG. 5) is provided with a fifth pipe section 26, but the bubble reduction device 1 according to the third embodiment (see FIG. 7) is provided with a tapered pipe section 28 instead of the fifth pipe section 26. Also, while the bubble reduction device 1 according to the second embodiment exhausts air through the second exhaust section 27, the bubble reduction device 1 according to the third embodiment is configured to exhaust air through the third exhaust section 29.

The tapered tube section 28 is disposed so that the extension direction of the tube centerline extends in the vertical direction, and the lower end is fixed to the upper end of the fourth tube section 25. The tapered tube section 28 also has a lower tube section 28a and an upper tube section 28b that are continuous in the vertical direction.

The lower tube section 28a is formed so that its diameter gradually decreases as it goes upward, i.e., it has a roughly trumpet shape that expands in diameter as it goes downward. As a result, the inside of the tapered tube section 28 is tapered as it goes upward.

The upper tube section 28b is formed as a straight tube whose center line extends in the vertical direction.

The third exhaust section 29 has one end fixed to the upper end of the upper tube section 28b of the tapered tube section 28, and the other end connected to the gas exhaust pipe 6.

Next, we will explain the function of the bubble reduction device 1 according to the third embodiment.

When the tornado-shaped cavity generated by the above-mentioned centrifugation reaches the tapered tube section 28, it hits the inner surface of the tapered lower tube section 28a, that is, it is received by the inner surface of the tapered tube section 28 (lower tube section 28a), and is guided to the inner periphery side of the tapered tube section 28, that is, the center side where the upper tube section 28b is provided. This makes it possible to properly exhaust the liquid to the third exhaust section 29 via the upper tube section 28b. Therefore, by generating the tornado-shaped cavity radially outward from the center of the lower tube section 28a, it is possible to prevent the occurrence of a situation in which the liquid is not properly exhausted to the upper tube section 28b, that is, the liquid in the lower tube section 28a is mistakenly discharged to the upper tube section 28b.

The gas exhausted to the third exhaust section 29 is exhausted by the gas exhaust pipe 6 connected to the third exhaust section 29 without using a vacuum device. As a result, air bubbles and foam contained in the liquid stored in the tank 2 are separated from the liquid by the foam reduction device 1 according to the third embodiment and exhausted from the gas exhaust pipe 6. This makes it possible to reduce the amount of foam in the tank 2, thereby preventing the foam from overflowing from the tank 2.

The discharge of liquid using the first liquid discharge path section 25a in the bubble reduction device 1 according to the third embodiment is the same as that in the bubble reduction device 1 according to the second embodiment, so a description thereof will be omitted.

As described above, in the third embodiment, when the tornado-shaped cavity passes through the tapered tube section 28 connected to the downstream end of the discharge path section 18, it hits the inner surface of the lower tube section 28a of the tapered tube section 28, which narrows in diameter as it goes downstream. In other words, it is received by the inner surface of the tapered tube section 28 (lower tube section 28a) and is guided to the inner circumference side of the tapered tube section 28. The tornado-shaped cavity guided to the inner circumference side is appropriately exhausted from the third exhaust section 29 connected to the downstream end of the tapered tube section 28. This makes it possible to prevent liquid from being discharged from the third exhaust section 29 mixed with gas.

Fourth embodiment of the present invention
Next, a fourth embodiment of the present invention will be described with reference to Figures 8 to 10. Note that a description of parts common to the first embodiment will be omitted, and only parts different from the first embodiment will be described. Note that, for convenience, the electric motor 11 is omitted in Figure 8.

In the bubble reduction device 1 of the first embodiment (see Figure 2), the gas centrifuged in the discharge path section 18 is exhausted from the first exhaust section 10, and the centrifuged liquid is discharged from the second tube section 20. In the bubble reduction device 1 of the fourth embodiment (see Figure 8), the gas centrifuged in the discharge path section 18 is exhausted from the fourth exhaust section 34 connected to the upper end of the first tube section 19, and the gas and liquid not exhausted from the fourth exhaust section 34 are centrifuged into gas and liquid in the sixth tube section 30, and then the gas is exhausted from the fifth exhaust section 31 provided in the sixth tube section 30. In addition, in the bubble reduction device 1 according to the first embodiment (see FIG. 3), the lower end of the second pipe section 20 is fixed to the upper end of the first pipe section 19, but in the bubble reduction device 1 according to the fourth embodiment (see FIGS. 8 and 9), a second cover section 32 is attached to the opening at the upper end of the first pipe section 19, and a fourth exhaust section 34 is inserted into a through hole provided in the center of the second cover section 32.

The sixth tube section 30 is disposed around the discharge passage section 18 and the first tube section 19 with the extension direction of the tube center line extending in the vertical direction. The sixth tube section 30 has a closed lower end, while its upper end is connected to a liquid discharge tube 5 (not shown in FIG. 8). Furthermore, a fifth exhaust section 31 extending in a substantially horizontal direction is provided in the middle of the sixth tube section 30 in the vertical direction. The fifth exhaust section 31 has an inlet 31a provided in its inner peripheral portion located in the inner peripheral region of the sixth tube section 30. A U-shaped section 31b opening downward is provided in the middle of the sixth tube section 30, and the fifth exhaust section 31 is connected to the upper end of the U-shaped section 31b. Meanwhile, the outer peripheral end of the fifth exhaust section 31 protrudes radially outward from the outer peripheral surface of the sixth tube section 30 and is connected to a gas exhaust tube 6 (not shown in FIG. 8).

The sixth pipe section 30 is also connected to the first pipe section 19 via a connecting pipe section 33. One end of the connecting pipe section 33 is connected to a second liquid discharge path section 19a (see Figures 8 and 9) provided in the first pipe section 19.

The other end of the connection pipe section 33 is connected to the inlet port section 30a provided in the sixth pipe section 30. The inlet port section 30a is connected tangentially to the inner wall surface of the sixth pipe section 30 as shown in FIG. 10. In other words, when the other end of the connection pipe section 33 is attached to the inlet port section 30a, the other end of the connection pipe section 33 is connected tangentially to the inner wall surface of the sixth pipe section 30. In this embodiment, the inlet 31a and the U-shaped section 31b provided in the inner peripheral portion of the fifth exhaust section 31 are located above the portion to which the connection pipe section 33 is connected in the sixth pipe section 30 and in the inner peripheral region of the sixth pipe section 30. The inner peripheral region is, for example, set to the region in which the tornado-shaped cavity generated in the sixth pipe section 30 exists, that is, the region in which the tornado-shaped cavity can be introduced from the inlet 31a into the fifth exhaust section 31.

Next, the function of the bubble reduction device 1 according to the fourth embodiment will be described.

By ejecting the gas-liquid mixture from the ejection port 22 into the discharge path 18, a tornado-shaped cavity is generated in the inner peripheral region of the discharge path 18, while a swirling flow of liquid is generated in the outer peripheral region of the discharge path 18. When the upper end of the tornado-shaped cavity reaches the second cover 32, it is introduced into the fourth exhaust section 34 inserted into the through hole of the second cover 32 and exhausted. Meanwhile, the liquid swirling in the outer peripheral region of the discharge path 18 and the gas not exhausted from the fourth exhaust section 34, i.e., the gas-liquid mixture, are ejected from the first tube 19 to the connecting tube 33 via the second liquid discharge path 19a. When the gas-liquid mixture ejected into the connecting tube 33 is introduced into the sixth tube 30 via the introduction port 30a, a strong swirling flow is generated in the sixth tube 30, causing it to be centrifuged into gas and liquid. As a result, a tornado-shaped cavity extending in the vertical direction is generated in the inner peripheral region of the sixth tube section 30, as shown in FIG. 8. When the tornado-shaped cavity reaches the U-shaped section 31b, it is introduced into the U-shaped section 31b. The tornado-shaped cavity introduced into the U-shaped section 31b is then introduced into the fifth exhaust section 31 from the inlet 31a provided in the inner peripheral portion of the fifth exhaust section 31. The tornado-shaped cavity introduced into the fifth exhaust section 31, i.e., the gas, is exhausted to the gas exhaust pipe 6 connected to the fifth exhaust section 31, and is exhausted from the gas exhaust pipe 6 to the outside without using a vacuum device. As a result, the air bubbles and foam contained in the liquid stored in the tank 2 are centrifuged with the liquid by the foam reduction device 1 according to the fourth embodiment, and are exhausted from the gas exhaust pipe 6. Therefore, it is possible to reduce the foam in the tank 2, and it is possible to prevent the foam from overflowing from the tank 2.

On the other hand, the swirling flow of liquid generated in the outer peripheral region of the sixth pipe section 30 by the centrifugal separation in the sixth pipe section 30 is not discharged from the fifth exhaust section 31, but is discharged into the liquid discharge pipe 5 connected to the upper end of the sixth pipe section 30.

As described above, in the fourth embodiment, a gas-liquid mixture is discharged from the connecting tube section 33 into the sixth tube section 30, generating a vortex in the sixth tube section 30. Then, a tornado-shaped cavity is generated in the sixth tube section 30 by centrifugal separation caused by the vortex, and the gas forming the tornado-shaped cavity is introduced from the inlet 31a into the fifth exhaust section 31 and exhausted, so that the centrifuged gas can be appropriately exhausted.

In addition, in the fourth embodiment, the other end of the connecting pipe section 33 was connected tangentially to the inner wall surface of the sixth pipe section 30, but the other end of the connecting pipe section 33 may be connected tangentially to the inner wall surface of the sixth pipe section 30.

In addition, in the fourth embodiment, the fourth exhaust section 34 is provided, but the fourth exhaust section 34 does not have to be provided.

In the first to fourth embodiments, the foam reduction device 1 is installed in a machining factory, but the foam reduction device 1 may also be installed in a chemical factory (e.g., a chemical factory equipped with a tank for ethylene glycol, etc.), a food factory (e.g., a food factory equipped with a drainage tank), a plating factory (e.g., equipped with a plating tank), or a facility other than a factory.

In addition, in the first to fourth embodiments, as shown in FIG. 1, the liquid in which bubbles have been reduced by the bubble reduction device 1 is temporarily returned to the tank 2, and the liquid in the tank 2 is supplied to the machine tool 3 via the liquid supply pump 7. However, it is also possible to configure the liquid in which bubbles have been reduced by the bubble reduction device 1 to be directly supplied to the machine tool 3. With this configuration, the liquid supply pump 7 becomes unnecessary.

In the first to fourth embodiments, as shown in FIG. 1, the connection between the suction pipe 4 and the bubble reduction device 1 is located at a position higher than the liquid level in the tank 2. However, by lowering the position of the bubble reduction device 1, the connection between the suction pipe 4 and the bubble reduction device 1 can also be located at a position lower than the liquid level in the tank 2. With this configuration, the gas-liquid mixture is supplied from the tank 2 to the casing 14 without the need for self-priming operation by the pump 9.

In the first to fourth embodiments, the discharge path portion 18 is provided along the small volute chamber 16, but it may be provided so as to extend substantially horizontally and then substantially upward, as shown in FIG. 11. In this case, the cavity receiving portion 23 only needs to have a substantially horizontally flat shape, and may be provided, for example, as shown in FIG. 11, at a portion of the discharge path portion 18 corresponding to the ejection port 22, that is, at a portion capable of receiving from below the tornado-shaped cavity generated in the inner peripheral region of the discharge path portion 18 when the gas-liquid mixture is ejected from the ejection port 22 into the discharge path portion 18.

In addition, in the first to fourth embodiments, the downstream portion of the discharge passage section 18, the first pipe section 19, the second pipe section 20, the third pipe section 24, the fourth pipe section 25, the fifth pipe section 26, and the sixth pipe section 30 are arranged to extend in the vertical direction, but they may be arranged to extend in a direction other than the vertical direction (for example, the horizontal direction).

In the first and fourth embodiments, the discharge port 25b is not provided, but may be provided. In the first embodiment, the discharge port may be provided so as to open in a tangential direction to the inner wall surface of the first tube section 19 or the second tube section 20. In the fourth embodiment, instead of the second liquid discharge path section 19a provided in the first tube section 19, a discharge port may be provided so as to open in a tangential direction to the inner wall surface of the first tube section 19, and one end (upstream end) of the connection tube section 33 may be connected to the discharge port.

The present invention is suitable for a foam reduction device that can be used to reduce foam contained in a liquid.

1. Foam reducing device 2. Tank 9. Pump (self-priming centrifugal pump)
10 First exhaust section (exhaust section)
10a Umbrella-shaped portion (second hollow receiving portion)
10b First exhaust passage portion 13 Impeller 14 Casing 15 Suction port 16 Small volute chamber 17 Large volute chamber 18 Discharge passage portion (discharge pipe portion)
19 First pipe section (discharge pipe section)
20 Second pipe section (discharge pipe section)
21 Ejection path 23 Cavity receiving portion (first cavity receiving portion)
24 Third pipe section (discharge pipe section)
25 Fourth pipe section (discharge pipe section)
25b Discharge port 26 Fifth pipe section (discharge pipe section)
26a: First cover part (second hollow receiving part, closing part)
26b Through hole portion 27 Second exhaust portion (exhaust portion)
27a: Second exhaust passage portion 28: Tapered pipe portion (second hollow receiving portion)
29 Third exhaust section (exhaust section)
30 6th pipe section (other discharge pipe section)
31 Fifth exhaust section (exhaust section)
31a Inlet 31b U-shaped portion 33 Connection pipe portion 34 Fourth exhaust portion (exhaust portion)

Claims (8)

1. A foam reduction device that can be used to reduce foam in a liquid, comprising:
a self-priming centrifugal pump having an impeller housed in a casing, a suction port provided on the rotation axis of the impeller in the casing and for introducing a gas-liquid mixture into the casing, a large volute chamber and a small volute chamber provided around the impeller, a discharge pipe section connected to the large volute chamber, and a first cavity receiving section capable of receiving, from an upstream side, a tornado-shaped cavity generated in the discharge pipe section by ejecting the gas-liquid mixture from an ejection path connected to the small volute chamber into the discharge pipe section,
A bubble reduction device further comprising an exhaust section for naturally exhausting the gas forming the tornado-shaped cavity. 2. The foam reduction device according to claim 1,
A second cavity receiving portion capable of receiving the tornado-shaped cavity from the downstream side is provided,
A bubble reduction device characterized in that the exhaust section is configured to naturally exhaust the gas that forms the tornado-shaped cavity received in the second cavity receiving section. 3. The bubble reduction device according to claim 2,
The second cavity receiving portion has an umbrella shape and includes an umbrella portion capable of receiving the tornado-shaped cavity from a downstream side,
A bubble reduction device characterized in that the exhaust portion has a first exhaust passage portion connected to the inside of the umbrella-shaped portion. 3. The bubble reduction device according to claim 2,
the second hollow receiving portion includes a closing portion that closes a downstream end of the discharge pipe portion, and a through-hole portion that is formed through a central portion of the closing portion,
A bubble reduction device characterized in that the exhaust portion is provided with a second exhaust passage portion connected to the discharge pipe portion through the through hole portion or by being inserted into the through hole portion. 3. The bubble reduction device according to claim 2,
the second hollow receiving portion is connected to a downstream end of the discharge pipe portion and includes a tapered pipe portion configured to have a diameter that decreases toward the downstream side,
A bubble reduction device characterized in that the exhaust section is connected to the downstream end of the tapered pipe section. In the bubble reduction device according to any one of claims 1 to 5,
A bubble reduction device characterized in that the discharge pipe section is provided with a discharge port that opens in a tangential direction relative to the inner wall surface of the discharge pipe section. 7. The bubble reduction device according to claim 6,
A bubble reduction device characterized in that the portion of the discharge pipe section in which the discharge port is provided has an inner diameter larger than that of the portion upstream of the discharge pipe section. 2. The foam reduction device according to claim 1,
Another discharge pipe portion disposed around the discharge pipe portion;
a connecting pipe portion having one end connected to the discharge pipe portion and the other end connected to the other discharge pipe portion in a tangential direction to an inner wall surface of the other discharge pipe portion,
the exhaust section includes an inlet through which the gas in the other discharge pipe section is introduced into the exhaust section,
A bubble reduction device characterized in that the inlet is located downstream of the portion of the other discharge pipe section to which the connecting pipe section is connected, and in the inner circumferential region of the other discharge pipe section.

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