Defoaming device and defoaming method

Abstract

A defoaming device 100 comprises: a liquid supply unit 2 that supplies a liquid Lq to a tank 200; and a stirring unit 1 that stirs bubbles formed on a liquid surface Lf of the liquid Lq stored in the tank 200. The stirring unit 1 comprises: a shaft 12 that rotates about a center line C1 extending vertically; a power unit 13 that rotates the shaft 12; a stirring blade unit 11 that extends in a direction intersecting the center line C1, that is attached to the shaft 12, and that rotates according to the rotation of the shaft 12; and a rotational force transmission unit 14 that transmits the rotational force of the shaft 12 to the stirring blade unit 11. A spout 23 of the liquid supply unit 2 is disposed above the stirring blade unit 11.

Description

Defoaming Device and Defoaming Method

[0001] The present invention relates to a defoaming device and a defoaming method.

[0002] Conventionally, it has been known that bubbles are formed on the liquid surface of the liquid stored in a tank. When the liquid surface rises, even if the amount of the liquid in the tank is controlled to suppress the overflow of the liquid, the bubbles may overflow.

[0003] In order to suppress such an overflow, methods for defoaming bubbles have been proposed. For example, Patent Document 1 discloses a configuration for defoaming by irradiating bubbles with ultrasonic waves. Further, Patent Document 2 discloses a configuration for adding an antifoaming agent to the liquid to defoam the bubbles.

[0004] Japanese Unexamined Patent Application Publication No. 2022-112003

[0005] Japanese Unexamined Patent Application Publication No. 2022-07492

[0006] However, in the defoaming device that defoams by irradiating ultrasonic waves, a device for irradiating ultrasonic waves is required, the configuration of the defoaming device itself becomes complicated, and the probability of occurrence of defects increases. Further, in the defoaming device that defoams by adding an antifoaming agent, there is a risk that the properties of the liquid may change due to the addition of the antifoaming agent, and there is a concern that the original effect of the liquid may be weakened.

[0007] An object of the present invention is to provide a technique that can suppress the overflow of bubbles formed on the liquid surface of the liquid stored in a tank with a simple configuration.

[0008] To achieve the above object, the defoaming device includes a liquid supply unit that supplies liquid to a tank, and a stirring unit that stirs the bubbles formed on the liquid surface of the liquid stored in the tank. The stirring unit includes a shaft that extends along a center line extending vertically and rotates about the center line, a power unit that rotates the shaft, a stirring blade portion that extends in a direction intersecting the center line and is attached to the shaft and rotates in accordance with the rotation of the shaft, and a rotational force transmission unit that transmits the rotational force of the shaft to the stirring blade portion. The liquid outlet of the liquid supply unit is disposed above the stirring blade portion (first configuration).

[0009] In the defoaming device according to the first configuration, the stirring section includes a liquid level following section that causes the stirring blades to follow the rise and fall of the liquid level, such that at least a portion of the stirring blades is located above the liquid level of the liquid (second configuration).

[0010] In the defoaming device according to the second configuration, the liquid level following section is provided with a floating section on the stirring blade section, which is formed so that the stirring blade section floats on the liquid (third configuration).

[0011] In the defoaming device according to the second or third configuration, the rotational force transmission unit comprises a power transmission blade, one end of which is attached to the shaft and rotates together with the shaft, and which contacts the stirring blade unit in the circumferential direction (fourth configuration).

[0012] In a defoaming device according to any of the first to fourth configurations, the rotational force transmission unit comprises a sliding hole that penetrates a part of the stirring blade in the vertical direction and has an inner circumferential surface with a non-circular cross-sectional shape perpendicular to the center line, and a sliding shaft that is formed on at least a part of the shaft and is inserted into the sliding hole so as to be slidable vertically and has an outer circumferential surface with a non-circular cross-sectional shape perpendicular to the center line. When the shaft rotates, the outer circumferential surface of the sliding shaft unit contacts the inner circumferential surface of the sliding hole unit so as to be able to transmit the rotational force (fifth configuration).

[0013] In the defoaming device according to the first configuration, the liquid supply unit supplies the liquid such that the liquid level is between a predetermined upper limit and a predetermined lower limit, and the stirring unit comprises a first stirring blade unit having at least a portion that is positioned above the upper limit, and a second stirring blade unit having at least a portion that is positioned between the lower limit and the upper limit (sixth configuration).

[0014] To achieve the above objective, the defoaming method involves stirring the foam formed on the surface of the liquid stored in the tank, and injecting liquid so as to collide with the stirred foam (the seventh configuration).

[0015] In the defoaming method according to the seventh configuration, the stirring blade section, which agitates the foam, is moved up and down in accordance with the liquid level of the liquid stored in the tank (eighth configuration).

[0016] According to the present invention, it is possible to suppress the overflow of bubbles formed at the liquid surface of the liquid stored in the tank with a simple configuration.

[0017] Figure 1 is a schematic cross-sectional view of an example of a defoaming device installed in a tank when the liquid level is at its upper limit. Figure 2 is a schematic cross-sectional view of an example of a defoaming device installed in a tank when the liquid level is at its lower limit. Figure 3 is a block diagram showing the connection state of the defoaming device. Figure 4 is a cross-sectional view of the defoaming device. Figure 5 is a perspective view of the defoaming device. Figure 6 is an exploded perspective view of a part of the stirring blade section. Figure 7 is an exploded perspective view of the stirring blade section of the second embodiment. Figure 8 is an enlarged plan view showing the stirring blade section and shaft of the third embodiment. Figure 9 is an enlarged plan view of another example of the stirring blade section and shaft of the third embodiment. Figure 10 is a schematic cross-sectional view of an example of a defoaming device of the fourth embodiment. Figure 11 is a schematic arrangement diagram of a liquid handling device using the defoaming device. Figure 12 is a block diagram showing the connection state of the liquid handling device.

[0018] <First Embodiment> The detailed configuration of the defoaming device 100 will be described below with reference to the drawings. The defoaming device 100 will be described using the X, Y, and Z directions shown in Figure 5 as reference, as necessary. The X, Y, and Z directions are orthogonal to each other. In other words, in the defoaming device 100, the direction in which gravity acts and in which the shaft 12 extends is defined as the Z direction. The direction in which the impeller 111 extends, which is orthogonal to the Z direction, is defined as the X direction. Furthermore, the direction in which the impeller 111 is arranged, which is orthogonal to the Z and X directions, is defined as the Y direction. Note that each direction is defined to facilitate the following explanation and may not correspond to the actual usage conditions.

[0019] Figure 1 is a schematic cross-sectional view of an example of a defoaming device 100 installed in a tank 200 when the liquid level Lf is at the upper limit Lmx. Figure 2 is a schematic cross-sectional view of an example of a defoaming device 100 installed in a tank 200 when the liquid level Lf is at the lower limit Lmn. Figure 3 is a block diagram showing the connection state of the defoaming device 100. Figure 4 is a cross-sectional view of the defoaming device 100. Figure 5 is a perspective view of the defoaming device 100. Figure 6 is an exploded perspective view of a part of the stirring blade section 11.

[0020] <Tank 200> As shown in Figure 1, the tank 200 is a bottomed cylindrical shape with an upper opening 201 at its upper end. The tank 200 is equipped with a liquid level detection unit 202. Liquid Lq is stored inside the tank 200. If the liquid Lq is a foaming liquid, bubbles Bb are generated at the liquid level Lf of the liquid Lq as the liquid Lq flows into the tank 200. In other words, the liquid Lq foams in the tank 200. In the tank 200, bubbles Bb are generated at the liquid level Lf of the liquid Lq. Even if the amount of liquid Lq stored in the tank 200 is less than the capacity of the tank 200, bubbles Bb may overflow from the upper opening 201 of the tank 200.

[0021] The liquid level detection unit 202 is mounted on the inner circumferential surface of the tank 200. The liquid level detection unit 202 detects the liquid level Lf of the liquid Lq stored inside. The liquid level detection unit 202 detects at least the upper limit Lmx of the liquid level Lf in the tank 200. The upper limit Lmx of the liquid level Lf is the height of the liquid level Lf at which foam Bb does not overflow when the defoaming device 100 is operated. The liquid level detection unit 202 may be a level switch that detects when the liquid level Lf has reached a certain point, or it may be a liquid level gauge that continuously detects the position of the liquid level Lf.

[0022] When a level switch is used, the liquid level detection unit 202 may be positioned to detect when the liquid level Lf reaches the upper limit Lmx, or it may be positioned lower than the upper limit Lmx. Alternatively, it may be provided at multiple heights to detect when the liquid level Lf reaches multiple different heights.

[0023] The liquid level detection unit 202 used in the tank 200 in this embodiment is a liquid level gauge. In the tank 200, an upper limit Lmx and a lower limit Lmn of the liquid level Lf are set.

[0024] <Defoaming device 100> The defoaming device 100 defoams the foam Bb generated at the liquid surface Lf of the liquid Lq stored in the tank 200. The defoaming device 100 utilizes the phenomenon in which foam Bb is defoamed when liquid Lq is injected into the tank 200 due to collision with the liquid Lq. The details of the defoaming device 100 will be described below with reference to the drawings. As shown in Figures 1 and 5, the defoaming device 100 comprises a stirring unit 1, a liquid supply unit 2, a liquid surface tracking unit 3, and a control unit 4.

[0025] <Control Unit 4> As shown in Figure 3, the stirring unit 1 and the liquid supply unit 2 of the defoaming device 100 are connected to the control unit 4. The control unit 4 sends control signals to the connected devices and controls the operation of the connected devices. The control unit 4 may be equipped with arithmetic circuits such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit), or it may be a circuit formed by combining multiple elements.

[0026] As shown in Figure 3, the control unit 4 is connected to the liquid level detection unit 202 provided in the tank 200. The control unit 4 obtains information on the liquid level Lf of the liquid Lq stored in the tank 200 from the liquid level detection unit 202. As shown in Figure 3, the control unit 4 controls the operation of the stirring unit 1 and the liquid supply unit 2.

[0027] <Liquid Supply Unit 2> The liquid supply unit 2 supplies liquid Lq from the upper opening 201 of the tank 200. The liquid supply unit 2 comprises a liquid supply pipe 21 and a flow rate adjustment unit 22. The liquid supply pipe 21 is a pipe that supplies liquid Lq from the liquid supply unit 2 to the tank 200. The liquid supply pipe 21 is equipped with a dispensing outlet 23 for dispensing liquid Lq.

[0028] The flow rate adjustment unit 22 adjusts the flow rate of liquid Lq supplied from the liquid supply unit 2 to the tank 200 based on instructions from the control unit 4. The flow rate adjustment unit 22 is provided, for example, in the liquid supply piping 21. Examples of the flow rate adjustment unit 22 include a flow rate adjustment valve, a pump, or a combination thereof. However, it is not limited to these, and the flow rate adjustment unit 22 can employ a wide range of configurations that can adjust the flow rate of liquid Lq.

[0029] The control unit 4 controls the flow rate adjustment unit 22 based on the liquid level Lf information from the liquid level detection unit 202. The liquid Lq stored in the tank 200 is sent to a liquid usage unit located outside the tank 200 for use. As it is used in the liquid usage unit, the amount of liquid Lq decreases. The tank 200 is equipped with a pipe (liquid supply pipe 301 shown in Figure 12, described later) for taking out the liquid Lq stored inside, and when the suction port 303 of the liquid supply pipe 301 rises above the liquid level Lf, no more liquid Lq is taken out. Therefore, for example, while the liquid level Lf of the liquid Lq stored in the tank 200 is between the upper limit Lmx and the lower limit Lmn, the control unit 4 controls the flow rate adjustment unit 22 so that a constant amount of liquid Lq is dispensed from the outlet 23.

[0030] Furthermore, when the liquid level Lf reaches the upper limit Lmx, the control unit 4 controls the flow rate adjustment unit 22 so that the liquid Lq stops flowing. Also, when the liquid level Lf reaches the lower limit Lmn, the control unit 4 controls the flow rate adjustment unit 22 so that the flow rate of liquid Lq increases. Note that the control of the flow rate adjustment unit 22 described above is just one example and is not limited to this control. The control unit 4 can widely employ a control method that ensures that the liquid level Lf of the liquid Lq stored in the tank 200 does not exceed the upper limit Lmx.

[0031] The upper limit Lmx is determined based on the condition that when bubbles Bb are formed at the liquid level Lf of the liquid Lq, the bubbles Bb do not overflow from the upper opening 201 of the tank 200. In other words, the upper limit Lmx changes depending on the type of liquid Lq, temperature, ambient temperature, and other factors that cause bubbles Bb to form. The lower limit Lmn is determined so that the suction port 303 of the liquid supply piping 301 does not rise above the liquid level Lf. Therefore, the lower limit Lmn is determined by the height of the suction port 303 of the liquid supply piping 301.

[0032] The position of the liquid supply pipe 21 relative to the upper opening 201 of the tank 200 is fixed. That is, the liquid Lq dispensed from the liquid supply pipe 21 is poured to a predetermined position on the liquid surface Lf when viewed from the Z direction. At this time, the liquid Lq collides with the bubbles Bb formed on the liquid surface Lf, causing the bubbles Bb to be defoamed. The region where the liquid Lq collides with the liquid surface Lf when viewed from the Z direction is defined as the defoaming region ArD.

[0033] Even if the spout 23 is surrounded by bubbles Bb, the liquid Lq dispensed from the spout 23 will still collide with the bubbles Bb. Therefore, the spout 23 should be positioned above the liquid level Lf when the liquid level Lf is at the upper limit Lmx. It is even more preferable that the spout 23 be positioned above the bubbles Bb when the liquid level Lf is at the upper limit Lmx. Furthermore, by positioning the spout 23 above the upper opening 201 of the tank 200, the bubbles Bb are reliably defoamed. This ensures that the liquid Lq is supplied in a way that prevents the bubbles Bb from overflowing from the upper opening 201 of the tank 200.

[0034] As shown in Figure 4, the area of ​​the spout 23 is smaller than the area of ​​the upper opening 201 of the tank 200. Therefore, the area of ​​the defoaming region ArD is smaller than the area of ​​the liquid surface Lf. As described above, in the defoaming device 100, foam Bb is defoamed by causing the liquid Lq dispensed from the spout 23 to collide with the foam Bb. Therefore, if liquid Lq is simply dispensed from the spout 23, which is fixed to the upper opening 201 of the tank 200, the amount of foam Bb that is defoamed by collision with the liquid Lq is small. Furthermore, foam Bb in the part of the liquid surface Lf other than the defoaming region ArD is difficult to defoam.

[0035] Therefore, in the defoaming device 100 of this embodiment, the stirring unit 1 stirs the foam Bb, thereby sequentially sending the foam Bb outside the defoaming region ArD to the defoaming region ArD. As a result, foam Bb located over a wide area of ​​the liquid surface Lf is sent to the defoaming region ArD and sequentially defoamed. Next, the detailed configuration of the stirring unit 1 will be explained with reference to the drawings.

[0036] As shown in Figures 1, 3 to 5, the stirring unit 1 comprises a stirring blade 11, a shaft 12, a stirring motor 13, and a rotational force transmission unit 14. As shown in Figure 4, when viewed from the Z direction, the center line C1 of the stirring unit 1 is offset from the center of the tank 200. However, the arrangement is not limited to this, and the center line C1 of the stirring unit 1 may coincide with the center of the tank 200. The center line C1 of the stirring unit 1 is not limited to the above position as long as it is in a position where the impeller 111 of the stirring unit 1 and the inner circumferential surface of the tank 200 do not interfere when the stirring unit 1 is rotated inside the tank 200.

[0037] The stirring motor 13 is mounted on a mounting portion 203 located in the upper opening 201 of the tank 200. The stirring motor 13 is the power unit that rotates the shaft 12. In the stirring unit 1, the output shaft 131 of the stirring motor 13 passes through the mounting portion 203 and is connected to the shaft 12, a so-called direct drive. However, the stirring unit 1 may have a reduction gear interposed between the output shaft 131 of the stirring motor 13 and the shaft 12. The power unit may receive rotational force from an external power source to the stirring unit 1 using gears, pulleys, belts, etc.

[0038] The shaft 12 is cylindrical and extends vertically along the Z-direction. The upper end of the shaft 12 is connected to the output shaft 131 of the stirring motor 13. Driven by the stirring motor 13, the shaft 12 rotates around the center line C1. As shown in Figures 4 and 5, the stirring direction is counterclockwise when viewed from the Z-direction. In the following explanation, the direction along the center line C1, i.e., the Z-direction, may be referred to as the axial direction. Also, the tangential direction when rotating around the center line C1 may be referred to as the circumferential direction.

[0039] The shaft 12 is provided with a stopper portion 121. The stopper portion 121 is provided at the lower end of the shaft 12 in the Z direction, that is, at the tip of the shaft 12. The stopper portion 121 is disc-shaped and extends outward from the outer circumferential surface of the shaft 12. The stopper portion 121 may be integral with the shaft 12. Alternatively, the stopper portion 121 may be attached to the shaft 12 by fixing methods such as adhesive, welding, screw fastening, etc.

[0040] As shown in Figures 4 to 6, the stirring blade section 11 comprises two impellers 111, six ribs 112, and a hub section 114. The two impellers 111 are rectangular flat plates. The two impellers 111 are arranged such that the X direction is the longitudinal direction, and the thickness direction and alignment direction are the Y direction.

[0041] The length of the impeller 111 in the X direction is set so that when it rotates inside the tank 200, the impeller 111 does not interfere with the inner surface of the tank 200. When the stirring unit 1 rotates, the impeller 111 pushes the bubbles Bb, moving them to the defoaming region ArD. When viewed from the Z direction, the stirring unit 1 is preferably positioned so that when the stirring blades 11 rotate around the shaft 12, the impeller 111 crosses the defoaming region ArD. In this case, the outlet 23 of the liquid supply pipe 21 is preferably positioned so as not to interfere with the stirring blades 11, based on the position of the stirring blades 11 when the liquid level Lf is at the upper limit Lmx. One example of such a position is that the outlet 23 is positioned above the upper end of the stirring blades 11 in the Z direction. In addition to this, a wide range of positions can be adopted in which the stirring blades 11 and the liquid supply pipe 21 do not interfere with each other.

[0042] The six ribs 112 are each fixed to both of the two impellers 111. That is, the six ribs 112 connect the two impellers 111. The six ribs 112 are fixed to the impellers 111 at positions that are symmetric with respect to the center line C1 when viewed from the Z direction. By connecting the impellers 111 with the six ribs 112, the rigidity when the stirring blade part 11 rotates is increased. As shown in FIG. 6, the space between the two impellers 111 and sandwiched by adjacent ribs 112 is the storage part 113. Five storage parts 113 are formed in the stirring blade part 11. The hub part 114 is stored in the central storage part 113. Further, the floating part 31 of the liquid level following part 3 is stored in the remaining storage parts 113 (see FIG. 6).

[0043] As shown in FIG. 6, the hub part 114 has a rectangular parallelepiped shape. The hub part 114 is sealed with air (or gas) enclosed inside. That is, the hub part 114 has the same configuration as the floating part 31 of the liquid level following part 3 and acts as a part of the liquid level following part 3. After the hub part 114 is stored in the storage part 113, it is fixed to the impeller 111 and the ribs 112. Thereby, the hub part 114 is integrated with the impeller 111 and the ribs 112. Note that, for fixing the hub part 114, fixing methods such as adhesion, welding, press-fitting, etc. can be adopted. Further, the fixing method may be other than these as long as the hub part 114 can be firmly fixed to the impeller 111 and the ribs 112.

[0044] The hub part 114 is provided with an inner cylinder part 115 penetrating in the Z direction at the central part when viewed from the Z direction. When viewed from the Z direction, the inner cylinder part 115 is located at the center of gravity of the stirring blade part 11. And the shaft 12 penetrates the inner cylinder part 115 in the Z direction. At this time, the shaft 12 is movable in the Z direction and rotatable in the circumferential direction in the inner cylinder part 115. That is, the stirring blade part 11 is rotatable with respect to the shaft 12 and movable in the Z direction with respect to the shaft 12.

[0045] Note that the outer peripheral surface of the shaft 12 and the inner peripheral surface of the hub part 114 may be non-contact, or at least a part may be in contact. It is only necessary that the hub part 114 is movable in the Z direction and the circumferential direction with respect to the shaft 12.

[0046] Further, when the stirring blade portion 11 moves to the lower end portion of the shaft 12, the hub portion 114 comes into contact with the stopper portion 121 (see FIG. 2). Thereby, the separation of the stirring blade portion 11 from the shaft 12 is suppressed. In the defoaming device 100 of the present embodiment, the stopper portion 121 with which the hub portion 114 comes into contact is arranged when the liquid Lq stored in the tank 200 reaches the lower limit Lmn, but it is not limited thereto. For example, the stopper portion 121 may be arranged above the lower limit Lmn of the liquid surface Lf. Further, when the lower end of the shaft 12 is always positioned below the liquid surface Lf, the stopper portion 121 may be omitted.

[0047] In the stirring unit 1, the rotational force transmission unit 14 transmits the rotational force of the shaft 12 to the stirring blade portion 11, whereby the stirring blade portion 11 is rotated. As shown in FIGS. 1, 4, 5, etc., the rotational force transmission unit 14 includes a support portion 141, a transmission blade 142, and a pin 143. The support portion 141 is arranged at the upper part in the Z direction of the outer peripheral surface of the shaft 12. The support portion 141 protrudes outward from the outer peripheral surface of the shaft 12. Note that the support portion 141 may be formed integrally with the shaft 12. Also, the support portion 141 may be fixed to the shaft 12 using fixing methods such as adhesion, welding, brazing, press-fitting, etc. That is, the support portion 141 rotates integrally with the shaft 12 as the shaft 12 rotates. As shown in FIG. 5, the width of the support portion 141 has the same width as the width of the stirring blade portion 11. Note that the support portion 141 may serve as an upper stopper that restricts the upward movement of the stirring blade portion 11.

[0048] The transmission blade 142 is in the shape of a long plate. The upper end portion in the longitudinal direction of the transmission blade 142 is swingably supported by the support portion 141 via the pin 143. The transmission blade 142 is swingable about the pin 143 so as to approach or separate from the shaft 12 in a direction along the radial direction of the shaft 12.

[0049] The transmission blade 142 rotates in conjunction with the rotation of the shaft 12. At this time, the transmission blade 142 contacts one side of the impeller 111 of the stirring blade section 11 in the thickness direction. As a result, the rotational force of the shaft 12 is transmitted to the impeller 111 of the stirring blade section 11, and the stirring blade section 11 rotates in accordance with the rotation of the shaft 12. The length of the transmission blade 142 is such that it can contact the impeller 111 of the stirring blade section 11 regardless of its vertical orientation.

[0050] The transmission blade 142 is pivotable around the support portion 141, but is not limited to this. For example, the transmission blade 142 may be fixed to the shaft 12. When the transmission blade 142 is fixed to the shaft 12, it may be fixed at an angle to the shaft 12 or parallel to the shaft 12. The transmission blade 142 can be configured to transmit the rotational force of the shaft 12 to the stirring blade portion 11.

[0051] Furthermore, in the stirring section 1, if the transmission blade 142 is pivotably supported by the support section 141, when the shaft 12 is not rotating, the transmission blade 142 is positioned along the shaft 12. This makes the stirring section 1 compact when the shaft 12 is not rotating. Also, when the shaft 12 rotates, if the lower end of the transmission blade 142 moves away from the shaft 12, the transmission blade 142 pushes against the far end of the impeller 111. This allows the transmission blade 142 to apply greater torque to the impeller 111.

[0052] As described above, when viewed from the Z direction, the inner cylinder portion 115 of the hub portion 114 coincides with the center of gravity of the shape of the stirring blade portion 11. Therefore, when the stirring blade portion 11 rotates around the shaft 12, it rotates around the center of gravity. As a result, the stirring blade portion 11 rotates in a balanced manner, and vibrations, wobble, etc., are suppressed.

[0053] In the stirring section 1, a liquid level following section 3 is attached to the stirring blade section 11. As shown in Figures 4 to 6, the liquid level following section 3 is equipped with four floating sections 31. Each of the four floating sections 31 is rectangular in shape and is stored in a storage section 113 formed by the impeller 111 and ribs 112 of the stirring blade section 11. The floating sections 31 stored in the storage section 113 are then fixed to the impeller 111 and ribs 112. The fixing method may be the same as or different from the fixing method for the hub section 114 to the impeller 111 and ribs 112.

[0054] The floating portion 31 and the hub portion 114 have a structure in which air (or a specific gas) is sealed inside, that is, a hollow structure. By fixing the floating portion 31 and the hub portion 114 with such a structure to the impeller 111 and the rib 112, the overall specific gravity of the stirring blade portion 11 becomes less than that of the liquid Lq.

[0055] By making the overall specific gravity of the stirring blade section 11 less than the specific gravity of the liquid Lq, the stirring blade section 11 floats on the liquid surface Lf of the liquid Lq stored in the tank 200. Here, floating on the liquid surface Lf means that at least a part of the stirring blade section 11 is exposed above the liquid surface Lf. To explain further, the size of the portion of the stirring blade section 11 that is exposed above the liquid surface Lf depends on the overall specific gravity of the stirring blade section 11. The stirring blade section 11 stirs the bubbles Bb that are formed above the liquid surface Lf. Therefore, it is preferable that the portion of the stirring blade section 11 that protrudes above the liquid surface Lf is large. In other words, it is preferable that the floating portion 31 has as low a specific gravity as possible.

[0056] In the stirring blade section 11 of this embodiment, the hub section 114 and the float section 31 protrude above the upper end of the impeller 111 in the Z direction. If the overall specific gravity of the stirring blade section 11 can be made sufficiently low, the float section 31 and the hub section 114 may be configured not to protrude from the upper end of the impeller 111.

[0057] By using the floating part 31 as the liquid level following part 3, the stirring blade part 11 floats on the liquid level Lf of the liquid Lq. As a result, the stirring blade part 11 moves up and down in accordance with the rise and fall of the liquid level Lf, that is, it moves up and down following the liquid level Lf.

[0058] Furthermore, the specific gravity of the foam Bb is lower than that of the liquid Lq. Therefore, when the stirring blade 11 stirs the foam Bb, the less of the stirring blade 11 is submerged in the liquid Lq, the less load is placed on the stirring motor 13. In other words, the less of the stirring blade 11 is submerged in the liquid Lq, the smaller the stirring motor 13 can be made.

[0059] Alternatively, the four floating sections 31 and hub sections 114 may be arranged side by side and fixed to each other, and the impeller 111 may be fixed to the sides of the floating sections 31 and hub sections 114. With this configuration, the ribs 112 can be omitted.

[0060] Next, the operation of the defoaming device 100 to defoam the foam Bb generated at the liquid surface Lf of the liquid Lq stored in the tank 200 will be explained.

[0061] As described above, the control unit 4 acquires information on the liquid level Lf from the liquid level detection unit 202 of the tank 200. Based on the information on the liquid level Lf of the tank 200, the control unit 4 controls the flow rate adjustment unit 22 so that the liquid level Lf is between the upper limit Lmx and the lower limit Lmn. As a result, the flow rate of the liquid Lq supplied to the tank 200 is adjusted, and the liquid level Lf of the liquid Lq stored in the tank 200 rises and falls between the upper limit Lmx and the lower limit Lmn.

[0062] In this case, the liquid supply pipe 21 of the liquid supply unit 2 is a pipe that extends vertically along the Z direction, and the liquid Lq is dispensed downward along the Z direction from the outlet 23 at the lower end. Therefore, even if the height of the liquid level Lf changes, the position of the defoaming region ArD, as viewed from the Z direction, remains almost the same. In other words, even if the height of the liquid level Lf changes, the amount of foam Bb that is defoamed in the defoaming region ArD remains almost the same.

[0063] In the defoaming device 100, the stirring blade section 11 is floating on the liquid surface Lf and rotates around the center line C1. In other words, the stirring blade section 11 rotates while floating on the liquid surface Lf, and the impeller 111 of the stirring blade section 11 pushes and agitates the bubbles Bb formed on the liquid surface Lf. As a result, bubbles Bb in areas other than the defoaming region ArD are sent to the defoaming region ArD, and bubbles Bb that were distributed throughout the entire liquid surface Lf are defoamed.

[0064] In the stirring section 1, the stirring blade section 11 floats on the liquid surface Lf even when rotating. Therefore, even when rotating, the stirring blade section 11 moves up and down in accordance with the rise and fall of the liquid surface Lf. In other words, regardless of the height of the liquid surface Lf, the bubbles Bb formed on the liquid surface Lf are stirred by the stirring blade section 11. Even when liquid Lq is supplied from the liquid supply section 2 and the liquid surface Lf is rising and falling, the bubbles Bb formed on the liquid surface Lf are pushed toward the defoaming region ArD (see Figure 4, etc.). Therefore, the defoaming device 100 can defoam bubbles Bb even when the liquid surface Lf is fluctuating.

[0065] As described above, a portion of the stirring blade section 11 may be submerged in the liquid Lq. In this state, if the rotation speed of the stirring blade section 11 is high, the rotation of the stirring blade section 11 may generate foam Bb. The main purpose of the stirring blade section 11 is to send the foam Bb to the defoaming region ArD by stirring it, and it does not need to rotate at high speed. In other words, in the defoaming device 100, the rotation speed of the stirring blade section 11 of the stirring section 1 can be, for example, around 10 rpm. The rotation speed of the stirring blade section 11 should be such that foam Bb is not generated and the load on the stirring motor 13 is reduced.

[0066] <Second Embodiment> Figure 7 is an exploded perspective view of the stirring blade section 11A of the second embodiment. The stirring blade section 11A shown in Figure 7 differs from the stirring blade section 11 in that it has a bottom plate section 116 and a top plate section 117, and omits the hub section 114 and the float section 31. In all other respects, the stirring blade section 11A has the same configuration as the stirring blade section 11. Therefore, the same reference numerals are used for the same parts of the stirring blade section 11A as for the stirring blade section 111, and detailed descriptions of these same parts are omitted.

[0067] As shown in Figure 7, the stirring blade section 11A comprises a bottom plate section 116 and a top plate section 117. The bottom plate section 116 is plate-shaped and fixed to the lower ends of the two impellers 111 and the lower ends of the six ribs 112. The top plate section 117 is also plate-shaped and fixed to the upper ends of the two impellers 111 and the upper ends of the six ribs 112. The bottom plate section 116 has a through hole 118 formed in the central part when viewed from the Z direction, penetrating in the Z direction. The top plate section 117 has a through hole 119 formed in the central part when viewed from the Z direction, penetrating in the Z direction. The centers of the through holes 118 and 119 coincide with the center line C1.

[0068] As a result, in the stirring blade section 11A, the storage section 113 is sealed by the bottom plate section 116 and the top plate section 117. The storage section 113 is sealed with air (or gas) inside. Because the storage section 113 is sealed, the stirring blade section 11A floats on the liquid level Lf of the liquid Lq. In other words, the storage section 113 plays the same role as the floating section 31. A cylindrical sleeve connecting the through holes 118 and 119 may also be provided. With this configuration, the central storage section 113 can also be sealed, and the overall specific gravity of the stirring blade section 11A can be made even lower.

[0069] In this way, by using the bottom plate portion 116 and the top plate portion 117, the number of components constituting the stirring blade portion 11A is reduced, and the manufacturing process of the stirring blade portion 11A can be reduced.

[0070] <Third Embodiment> Figure 8 is an enlarged plan view showing the stirring blade section 11B and shaft 12B of the third embodiment. As shown in Figure 8, the stirring blade section 11B differs from the stirring blade section 11 in that it is equipped with a rotational force transmission section 14B. In all other respects, the stirring blade section 11B has the same configuration as the stirring blade section 11. Therefore, the same reference numerals are used for the same parts of the stirring blade section 11B as for the stirring blade section 11, and detailed descriptions of these same parts are omitted.

[0071] As shown in Figure 8, the rotational force transmission section 14B comprises a sliding hole 144 formed in the stirring blade section 11B and a sliding shaft section 145 formed in the shaft 12B. The sliding hole 144 is located in the center of the hub section 114b when viewed from the Z direction, and penetrates the hub section 114b in the Z direction. The sliding hole 144 here is triangular in shape with rounded corners. In other words, the sliding hole 144 has a non-circular cross-sectional shape. The sliding shaft section 145 is formed in the Z direction of the shaft 12B, at least in the range where the stirring blade section 11B slides. The sliding shaft section 145 has a shape that allows it to slide in the Z direction within the sliding hole 144. The sliding shaft section 145 has a non-circular cross-sectional shape.

[0072] The sliding shaft portion 145 is formed in a range over which at least the stirring blade portion 11B of the shaft 12B slides in the Z direction. The sliding shaft portion 145 may also be formed over the entire length of the shaft 12B in the Z direction.

[0073] The sliding hole portion 144 and the sliding shaft portion 145 are formed in a triangular shape with rounded corners, so that when the shaft 12B rotates, the outer surface of the sliding shaft portion 145 contacts the inner surface of the sliding hole portion 144. As a result, the rotational force of the shaft 12B is transmitted to the stirring blade portion 11B. This configuration simplifies the structure of the stirring blade portion 11B. The cross-sectional shape of the sliding hole portion 144 and the sliding shaft portion 145 does not have to be circular. For example, as shown in Figure 9, a sliding hole portion 144B may be used which has a circular inner surface with a recess 146 that is recessed radially outward, and a sliding shaft portion 145B which has a circular outer surface with a convex portion 147 that protrudes radially. In addition, the cross-sectional shape of the sliding hole portion 144 and the sliding shaft portion 145 may be any other non-circular cross-sectional shape that is slidable in the Z direction and can transmit rotational force in the circumferential direction.

[0074] In the defoaming devices of each embodiment described above, the stirring blades can be reliably made to follow the liquid surface by using a liquid surface-following section with a simple configuration.

[0075] <Fourth Embodiment> Figure 10 is a schematic cross-sectional view of an example of the defoaming device 100C of the fourth embodiment. The defoaming device 100C shown in Figure 10 differs from the defoaming device 100 in that the stirring section 1C is different from the stirring section 1. All other parts of the stirring section 1C are the same as those of the defoaming device 100. Therefore, the same reference numerals are used for the parts of the defoaming device 100C that are the same as those of the defoaming device 100, and detailed explanations are omitted.

[0076] As shown in Figure 10, the stirring section 1C of the defoaming device 100C comprises one first stirring blade section 11C1 and two second stirring blade sections 11C2. The first stirring blade section 11C1 comprises two impellers 111c. The two impellers 111c are flat plates, fixed to the shaft 12, and extend in a direction intersecting the center line C1 (in this case, a perpendicular direction). At least a portion of the impellers 111c are positioned above the upper limit Lmx of the liquid level Lf of the liquid Lq stored in the tank 200. With this configuration, the first stirring blade section 11C1 can stir the bubbles Bb at the liquid level Lf when the liquid level Lf is at the upper limit Lmx.

[0077] Furthermore, each of the two second stirring blade sections 11C2 has the same configuration as the first stirring blade section 11C1. Both of the two second stirring blade sections 11C2 are positioned between the lower limit Lmn and the upper limit Lmx of the liquid level Lf. The two second stirring blade sections 11C2 are positioned vertically apart. Each second stirring blade section 11C2 is equipped with two impellers 110c. The two impellers 110c are flat plates, fixed to the shaft 12, and extend in a direction intersecting the center line C1 (in this case, a perpendicular direction).

[0078] The second stirring blade section 11C2 can stir the bubbles Bb that form on the liquid surface Lf when the liquid surface Lf of the liquid Lq stored in the tank 200 changes between the lower limit Lmn and the upper limit Lmx. This allows the bubbles Bb that form on the liquid surface Lf to be defoamed even when the liquid surface Lf moves up and down.

[0079] In this embodiment, the first stirring blade section 11C1 and the two second stirring blade sections 11C2 are arranged to overlap when viewed from the Z direction, but are not limited to this. The first stirring blade section 11C1 and the second stirring blade sections 11C2, and the second stirring blade sections 11C2 themselves, may be arranged offset from each other in the circumferential direction.

[0080] Furthermore, when the liquid level Lf of the liquid Lq stored in the tank 200 rises above a certain height, the second stirring blade section 11C2 is completely submerged in the liquid Lq. In this case, the second stirring blade section 11C2 rotates inside the liquid Lq, increasing the load on the stirring motor 13. Also, when the liquid level Lf is between the lower limit Lmn and the upper limit Lmx, the bubbles Bb are less likely to overflow from the upper opening 201 of the tank 200. For this reason, the projected area of ​​the impeller 110c of the second stirring blade section 11C2 in the rotational direction, that is, the width in the Z direction, may be smaller than that of the impeller 111c of the first stirring blade section 11C1.

[0081] Furthermore, the stirring section 1C of the defoaming device 100C is configured to include two second stirring blades 11C2, but is not limited to this configuration. For example, at least one second stirring blade 11C2 is sufficient if it is positioned between the lower limit Lmn and the upper limit Lmx.

[0082] The impeller 111c of the first stirring blade section 11C1 is not limited to two blades, but may be a single plate extending from the shaft 12 on both sides in the axial direction, or it may be three or more blades. Similarly, the impeller 110c of the second stirring blade section 11C2 is not limited to two blades, but may be a single plate extending from the shaft 12 on both sides in the axial direction, or it may be three or more blades.

[0083] In the above-described configurations, the stirring blades 11 (11A, 11B, 11C1, 11C2) are described as always rotating. The control unit 4 may operate to switch the rotation / stopping of the stirring blades 11 (11A, 11B, 11C1, 11C2) according to the height of the liquid level Lf. For example, if a tank 200 with a certain depth is used, when the height of the liquid level Lf is near the lower limit Lmn, bubbles Bb are less likely to overflow from the upper opening 201. Therefore, the control unit 4 may control the stirring motor 13 to rotate the stirring blades 11 (11A, 11B, 11C1, 11C2) when the liquid level Lf reaches a predetermined position between the lower limit Lmn and the upper limit Lmx. In this way, the power consumption of the stirring motor 13 can be kept low. Furthermore, the control unit 4 may control the stirring motor 13 to rotate the stirring blades 11 (11A, 11B, 11C1, 11C2) in conjunction with the supply of liquid from the liquid supply unit 2.

[0084] <Usage> Next, the liquid handling device 700 in which the defoaming device 100 is used will be described with reference to the drawings. Figure 11 is a schematic layout diagram of the liquid handling device 700 using the defoaming device 100. Figure 12 is a block diagram showing the connection state of the liquid handling device 700.

[0085] The liquid application apparatus 700 shown in Figure 11 is an example of a device that uses liquid. In this case, the liquid application apparatus 700 is a device that applies a liquid to the surface of a steel material in the annealing process to impart corrosion resistance and insulation properties to the steel material. In other words, the liquid application apparatus 700 shown in Figure 11 takes the transported steel material as the workpiece Wk and applies the liquid to the surface of the workpiece Wk. Note that the liquid application apparatus 700 is not limited to a device that applies liquid, but can also be a device that uses liquid to perform processing, such as a filling device that fills liquid into individual containers, or a cleaning device that cleans articles using liquid.

[0086] The liquid Lq applied during the annealing of steel materials is often a foaming liquid. When the foaming liquid Lq is circulated, it entrains air, and as the air-entrained liquid Lq is stored in the tank 200, bubbles Bb form at the liquid surface Lf. In the liquid handling device 700, the defoaming device 100 defoams the bubbles Bb that are generated at the liquid surface Lf of the liquid Lq stored in the tank 200. This prevents bubbles Bb from overflowing from the upper opening 201 of the tank 200.

[0087] As shown in Figure 11, the liquid usage device 700 includes a defoaming device 100, a tank 200, a liquid supply unit 300, a coating device 400, a return unit 500, and a liquid replenishment unit 600. Furthermore, as shown in Figure 12, the liquid usage device 700 includes a main control unit 800. The control unit 4 connected to the defoaming device 100 and the tank 200 is connected to the main control unit 800. The liquid supply unit 300, the coating device 400, the return unit 500, and the liquid replenishment unit 600 are also connected to the main control unit 800.

[0088] The control unit 4 receives information about the liquid usage device 700 from the main control unit 800. Based on the information from the main control unit 800, the control unit 4 controls the stirring motor 13 and the flow rate adjustment unit 22 as described above. The information sent from the main control unit 800 to the control unit 4 includes, for example, the timing of the start of processing for the workpiece Wk, the flow rate of liquid Lq in the liquid supply unit 300, the return unit 500, and the liquid replenishment unit 600, and the amount of liquid Lq remaining in the coating device 400. The control unit 4 also transmits information about the liquid level Lf of the tank 200 to the main control unit 800.

[0089] Furthermore, the liquid delivery unit 300, the coating device 400, the return unit 500, and the liquid replenishment unit 600 are controlled based on instructions from the main control unit 800.

[0090] As shown in Figure 11, in the liquid usage device 700, the liquid Lq stored in the tank 200 is sent to the coating device 400 via the liquid supply unit 300. In the coating device 400, the liquid Lq is applied to the surface of the workpiece Wk. The return unit 500 then returns a portion of the liquid Lq accumulated in the coating device 400 to the tank 200. In this way, the liquid Lq is circulated in the liquid usage device 700. Also, as the liquid Lq is applied to the workpiece Wk in the coating device 400, the liquid Lq is consumed and decreases. The liquid replenishment unit 600 supplies new liquid.

[0091] The liquid supply unit 300 comprises a liquid supply pipe 301 and a liquid supply flow rate adjustment unit 302. The liquid supply pipe 301 connects the tank 200 and the coating device 400. One end of the liquid supply pipe 301 is located inside the tank 200 (see Figures 1 and 2). The other end of the liquid supply pipe 301 is connected to the coating device 400. The liquid supply flow rate adjustment unit 302 adjusts the flow rate of liquid Lq flowing through the liquid supply pipe 301. The liquid supply flow rate adjustment unit 302 can be a flow control valve, a pump, or a combination thereof. In this case, the liquid supply flow rate adjustment unit 302 is a pump.

[0092] The liquid flow rate adjustment unit 302 is driven based on instructions from the main control device 800. When the liquid flow rate adjustment unit 302 is driven, the liquid Lq in the tank 200 is drawn in through the suction port 303 (see Figures 1 and 2) of the liquid supply piping 301 and sent to the coating device 400. The main control device 800 drives the liquid flow rate adjustment unit 302 when the annealing process of the steel plate starts and continues to drive the liquid flow rate adjustment unit 302 while the annealing process of the steel plate is ongoing. The main control device 800 may also control the liquid flow rate adjustment unit 302 from the control unit 4 to stop the flow of liquid Lq through the liquid supply piping 301 when the liquid level Lf in the tank 200 reaches the lower limit Lmn.

[0093] The coating apparatus 400 comprises a liquid reservoir pan 401, a brush 402, and a roller group 403. The liquid reservoir pan 401 is a container for storing liquid Lq. When a certain amount of liquid Lq accumulates in the liquid reservoir pan 401, the liquid Lq overflows. The overflowing liquid Lq flows into the return section 500.

[0094] The brush 402 is brush-shaped and applies liquid Lq to the surface of the workpiece Wk. The brush 402 adheres liquid Lq to the surface of the transported workpiece Wk. Liquid Lq from the liquid supply pipe 301 is supplied to the brush 402. Liquid Lq that is not adhered to the workpiece Wk by the brush 402 flows into the liquid reservoir pan 401.

[0095] The roller group 403 comprises multiple rollers. The multiple rollers are capable of holding liquid Lq. The multiple rollers include a first roller 404 that is in contact with the liquid Lq accumulated in the liquid reservoir pan 401, and a second roller 405 positioned close to the workpiece Wk. The outer circumferential surface of the first roller 404 and the outer circumferential surface of the second roller 405 are in contact. The first roller 404 is capable of holding liquid Lq on its outer circumferential surface. By rotating, the first roller 404 sends the liquid Lq from the liquid reservoir pan 401 to the surface of the second roller 405. By rotating, the second roller 405 is capable of moving relatively across the surface of the workpiece Wk. As the second roller 405 rotates and moves relatively across the surface of the workpiece Wk, the liquid Lq is applied to the surface of the workpiece Wk in a substantially uniform manner.

[0096] The first roller 404 and the second roller 405 of the roller group 403 are connected to the main control device 800. The main control device 800 controls the rotation of the first roller 404 and the second roller 405. For example, the main control device 800 drives the first roller 404 and the second roller 405 at the timing when the annealing process has started and the liquid Lq can be applied to the workpiece Wk from the second roller 405. For example, the first roller 404 and the second roller 405 are driven so that the surface of the second roller 405 is filled with liquid Lq at a timing slightly before the workpiece Wk arrives. In addition, if the workpiece Wk is conveyed intermittently, the main control device 800 may drive or stop the first roller 404 and the second roller 405 according to the timing when the workpiece Wk arrives at the coating device 400.

[0097] As the annealing process continues, liquid Lq is continuously supplied to the coating device 400. If the amount of liquid supplied remains greater than the amount of liquid being applied to the workpiece Wk, the liquid Lq will overflow from the liquid reservoir pan 401. The overflowed liquid Lq is returned to the tank 200 via the return unit 500.

[0098] As shown in Figure 11, the return section 500 comprises a return pipe 501 and a return flow rate adjustment section 502. The return pipe 501 connects the coating device 400 and the tank 200. Liquid Lq that overflows from the liquid reservoir pan 401 of the coating device 400 flows into the return pipe 501. The return flow rate adjustment section 502 adjusts the flow rate of liquid Lq flowing into the return pipe 501. The return flow rate adjustment section 502 can be a flow control valve, a pump, or a combination thereof. In this case, the return flow rate adjustment section 502 is a pump.

[0099] The return flow rate adjustment unit 502 is connected to the main control device 800 and is driven based on instructions from the main control device 800. The main control device 800 drives the return flow rate adjustment unit 502 when the annealing process of the steel plate is started. The drive of the return flow rate adjustment unit 502 continues while the annealing process is ongoing. The main control device 800 may also control the return flow rate adjustment unit 502 from the control unit 4 to stop the flow of liquid Lq through the return pipe 501 when the liquid level Lf in the tank 200 reaches the upper limit Lmx.

[0100] As the coating device 400 applies liquid Lq to the workpiece Wk, the amount of liquid Lq circulating in the liquid dispensing device 700 decreases. The liquid replenishment unit 600 replenishes the liquid Lq circulating in the liquid dispensing device 700. The liquid replenishment unit 600 comprises a replenishment container 601, a replenishment pipe 602, and a replenishment flow rate adjustment unit 603. Liquid Lq is contained inside the replenishment container 601. The replenishment pipe 602 sends the liquid Lq stored in the replenishment container 601 to the liquid supply unit 2 of the defoaming device 100. The replenishment pipe 602 is connected to the liquid supply unit 2. The liquid Lq from the replenishment pipe 602 is supplied to the liquid supply unit 2 of the defoaming device 100 and then supplied to the tank 200 via the liquid supply pipe 21.

[0101] The replenishment flow rate adjustment unit 603 is connected to the main control device 800 and operates based on instructions from the main control device 800. The replenishment flow rate adjustment unit 603 adjusts the amount of liquid Lq replenished from the replenishment container 601 to the liquid supply unit 2 via the replenishment piping 602. The replenishment flow rate adjustment unit 603 can be, for example, a pump or a valve, but is not limited to these. A replenishment flow rate adjustment unit 603 that can stop the flow of liquid when replenishment is not needed and flow the required amount of liquid Lq as needed is widely used. In this case, the replenishment flow rate adjustment unit 603 is a flow rate adjustment valve.

[0102] As shown in Figure 11, the liquid supply unit 2 of the defoaming device 100 is connected to the return pipe 501 of the return unit 500 and the replenishment pipe 602 of the liquid replenishment unit 600. Liquid flows into the liquid supply unit 2 from the return pipe 501 and the replenishment pipe 602. The liquid supply unit 2 is equipped with a flow rate adjustment unit 22, which is controlled by the control unit 4 to adjust the flow rate of the liquid supplied to the tank 200. In other words, the liquid supply unit 2 is a container (buffer) with a capacity to store a certain amount of liquid Lq from the return pipe 501 and the replenishment pipe 602.

[0103] Thus, in a liquid-using device 700 in which liquid Lq circulates, by placing the defoaming device 100 in the tank 200 where the liquid Lq is stored, the foam Bb at the liquid surface Lf of the liquid Lq stored in the tank 200 is defoamed. This prevents the foam Bb that forms at the liquid surface Lf as the liquid Lq is circulated in the liquid-using device 700 from overflowing.

[0104] 100, 100C Defoaming device 1, 1C Agitation section 11, 11A, 11B Agitation blade section 11C1 First agitation blade section 11C2 Second agitation blade section 110c Impeller 111, 111c Impeller 112 Rib 113 Storage section 114, 114b Hub section 115 Inner cylinder section 116 Bottom plate section 117 Top plate section 118 Through hole 119 Through hole 12, 12B Shaft 121 Stopper section 13 Agitation motor 131 Output shaft 14, 14B Rotational force transmission section 141 Support section 142 Transmission blade 143 Pin 144, 144B Sliding hole section 145, 145B Sliding shaft section 146 Recess 147 Protrusion 2 Liquid supply unit 21 Liquid supply piping 22 Flow rate adjustment unit 23 Dispensing outlet 3 Liquid level tracking unit 31 Floating unit 4 Control unit 200 Tank 201 Upper opening 202 Liquid level detection unit 203 Mounting unit 300 Liquid delivery unit 301 Liquid delivery piping 302 Liquid delivery flow rate adjustment unit 400 Coating device 401 Liquid storage pan 402 Brush 403 Roller group 500 Return unit 501 Return piping 502 Return flow rate adjustment unit 600 Liquid replenishment unit 601 Refill container 602 Refill piping 603 Flow rate adjustment unit 700 Liquid usage device 800 Main control device ArD Defoaming area Bb Foam C1 Centerline Lf Liquid level Lmn Lower limit Lmx Upper limit Lq Liquid Wk Work

Claims

1. A defoaming device comprising: a liquid supply unit for supplying liquid to a tank; and a stirring unit for stirring bubbles formed on the surface of the liquid stored in the tank, wherein the stirring unit comprises: a shaft extending along a vertically extending centerline and rotating about the centerline; a power unit for rotating the shaft; a stirring blade unit extending in a direction intersecting the centerline and attached to the shaft, which rotates in accordance with the rotation of the shaft; and a rotational force transmission unit for transmitting the rotational force of the shaft to the stirring blade unit, wherein the outlet for dispensing the liquid from the liquid supply unit is positioned above the stirring blade unit.

2. The defoaming device according to claim 1, wherein the stirring unit is provided with a liquid level following unit that causes the stirring blades to follow the rise and fall of the liquid level, such that at least a portion of the stirring blades is located above the liquid level of the liquid.

3. The defoaming device according to claim 2, wherein the liquid level following section is provided on the stirring blade section and comprises a floating section formed to cause the stirring blade section to float on the liquid.

4. The defoaming device according to any one of claims 1 to 3, wherein the rotational force transmission section comprises a power transmission blade, one end of which is attached to the shaft and rotates together with the shaft, and which contacts the stirring blade section in the circumferential direction.

5. The defoaming device according to any one of claims 1 to 4, wherein the rotational force transmission section comprises a sliding hole that penetrates a part of the stirring blade section in the vertical direction and has an inner circumferential surface with a non-circular cross-sectional shape perpendicular to the center line, and a sliding shaft section formed on at least a part of the shaft and inserted into the sliding hole so as to be slidable vertically and having an outer circumferential surface with a non-circular cross-sectional shape perpendicular to the center line, wherein when the shaft rotates, the outer circumferential surface of the sliding shaft section contacts the inner circumferential surface of the sliding hole section so as to be able to transmit the rotational force.

6. The defoaming device according to claim 1, wherein the liquid supply unit supplies the liquid such that the liquid level is between a predetermined upper limit and a predetermined lower limit, and the stirring unit comprises a first stirring blade section having at least a portion that is positioned above the upper limit, and a second stirring blade section having at least a portion that is positioned between the lower limit and the upper limit.

7. A method for defoaming, which involves stirring the bubbles formed on the surface of the liquid stored in a tank, and injecting liquid so as to collide with the stirring bubbles.

8. The defoaming method according to claim 7, wherein the stirring blade section for agitating foam is moved up and down in accordance with the liquid level of the liquid stored in the tank.

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