Deaeration system

Abstract

To provide a deaeration system which can deaerate a highly viscous liquid in a more reliable manner.SOLUTION: A deaeration system includes: a tank 3 for storing a viscous liquid; a pump 6 which exhausts a gas in the tank 3; and a control device 7 which controls the pump 6. The control device 7 sets a liquid surface of the inside of the tank 3 when the pump 6 is stopped as a reference liquid surface and causes the pump 6 to operate to exhaust the gas in the tank 3 and thereby form a foam layer at an upper part of the viscous liquid. Further, the control device 7 controls a displacement by the pump 6 so that the liquid surface of the foam layer becomes constant and continues exhaustion by the pump 6 until the foam layer is reduced to the reference liquid surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a degassing system for degassing highly viscous liquids. [Background technology]

[0002] In the manufacturing process of liquid products such as medicines, beverages, and ink, dissolved gas may be degassed. Since it takes a long time for highly viscous liquid products to be naturally degassed while stored in a tank, various degassing methods have been considered. For example, a method is known in which the liquid product is degassed by repeatedly venting gas from a tank storing the liquid product and then stopping the venting (see Patent Document 1).

[0003] However, because the pumping and stopping is repeated, the time required for degassing is longer and more energy is required to start and stop the pump. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-113303 A Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above circumstances, an object of the present invention is to provide a degassing system capable of degassing a viscous liquid. [Means for solving the problem]

[0006] A first aspect for achieving the above-mentioned object is a degassing system for degassing a viscous liquid having dissolved therein gas, comprising a tank for storing the viscous liquid, a pump for evacuating gas from inside the tank, and a control device for controlling the pump, wherein the control device defines the liquid level inside the tank when the pump is stopped as a reference liquid level, operates the pump to evacuate the gas from the tank to form a foamy layer on top of the viscous liquid, controls the amount of exhaust by the pump so that the liquid level of the foamy layer remains constant, and stops exhausting by the pump when the foamy layer shrinks to the reference liquid level. Effect of the Invention

[0007] According to the present invention, a degassing system capable of degassing a viscous liquid is provided. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a degassing system according to a first embodiment. [Diagram 2] FIG. 1 is a diagram showing a viscous liquid stored inside a tank. [Diagram 3] This is a graph showing the changes in the liquid level L1 of the foam layer and the amount of displacement by the pump. [Figure 4] FIG. 11 is a schematic diagram showing a tank in a degassing system according to a second embodiment. [Diagram 5] FIG. 11 is a schematic diagram showing a state in which a tank in a degassing system according to a second embodiment is used. [Figure 6] FIG. 11 is a schematic diagram showing a degassing system according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First Embodiment 1 is a schematic diagram of a degassing system 1. The degassing system 1 of the present embodiment includes a raw material supplying means 2, a tank 3, a liquid level gauge 5, an agitator 4, a pump 6, and a controller 7, and is a system for producing and degassing a viscous liquid.

[0010] A viscous liquid is a liquid that has gas dissolved in it and has a viscosity that causes bubbles to form when stirred or placed in a vacuum, as described below. The viscosity is about 3000 to 60000 [mPa s]. Examples of viscous liquids include liquid medicines, foods, beverages, and ink.

[0011] The raw material supplying means 2 is a group of devices that supply a viscous liquid raw material to the tank 3. The raw material supplying means 2 is composed of containers that hold a single raw material or two or more kinds of raw materials, pipes that connect the containers to the tank 3, valves that adjust the opening of the pipes, and a pump that transfers the raw material from the containers to the tank 3 by vacuum drawing. The raw material supplying means 2 is configured to supply the raw material to the tank 3 at a predetermined flow rate in response to a control signal from the control device 7, which will be described later.

[0012] The tank 3 is a container that stores a viscous liquid produced from raw materials supplied from the raw material supplying means 2. An agitating device 4 is attached to the tank 3. The agitating device 4 is a device that agitates the raw materials supplied into the tank 3. The multiple types of raw materials supplied from the raw material supplying means 2 are agitated by the agitating device 4 to produce a viscous liquid.

[0013] Although not shown, the tank 3 is provided with an openable / closable opening at the bottom of the tank 3, piping connected to the opening, and the like, as a configuration for transferring the stored viscous liquid to another tank or device. The viscous liquid can be transferred to another tank or device by a control signal from the control device 7.

[0014] The level gauge 5 is a device that measures the height of the liquid level of the viscous liquid stored in the tank 3. The height of the liquid level is the height of the liquid level of the viscous liquid based on the bottom of the tank 3. Various types of level gauges can be used for the level gauge 5. For example, laser type, ultrasonic type, capacitance type, radio wave type, pressure type, float type, etc. are included. In particular, it is preferable to use a laser type level gauge 5. The height of the liquid level measured by the level gauge 5 is transmitted to the control device 7.

[0015] The pump 6 is attached to the tank 3 so as to exhaust gas inside the tank 3. When the pump 6 operates, the inside of the tank 3 becomes negative pressure, and when the pump 6 stops, the inside of the tank 3 returns to normal pressure. The pump 6 is configured to operate, stop, or change its output in response to a control signal from the control device 7.

[0016] The control device 7 is also called a programmable controller (PLC) or sequencer. The control device 7 includes a CPU and a memory, and reads and executes a control program stored in the memory to obtain the liquid level from the liquid level gauge 5 and control the raw material supplying means 2, the agitator 4, and the pump 6.

[0017] Specific control by the control device 7 will be described with reference to Figures 2 and 3. Figure 2 shows the viscous liquid stored inside the tank, and Figure 3 shows the liquid level L1 of the foam layer and the transition of the amount of gas discharged by the pump. The amount of gas discharged outside the tank 3 (the gas that was originally in the tank 3 and the gas contained in the viscous liquid) is referred to as the amount of gas discharged. The horizontal axis of Figure 3 shows the time that has elapsed since the start of degassing. Also, the amount of gas discharged in Figure 3 shows the cumulative amount of gas discharged since the start of degassing.

[0018] As shown in Fig. 2(a), the control device 7 controls the raw material supply means 2 to supply various raw materials to the tank 3. The inside of the tank 3 is at normal pressure, and the liquid level of the viscous liquid in this state is set as the reference liquid level L0. After the raw materials are supplied, the control device 7 operates the pump 6 (time T0 in Fig. 3) to create a negative pressure inside the tank 3.

[0019] As shown in FIG. 2(b), when the inside of the tank 3 is subjected to negative pressure, a foamy layer B is formed on top of the viscous liquid A. The foamy layer B refers to the viscous liquid that has become foamy. As shown in FIG. 3, between time T0 and time T1, the liquid level L1 of the foamy layer B gradually rises. The foamy layer B refers to the part that is higher than the liquid level of the viscous liquid A at normal pressure. The foamy layer B is the gas dissolved in the viscous liquid A that has been made visible by the negative pressure. However, as shown in FIG. 2(b), the interface between the foamy layer B and the viscous liquid A is not necessarily clear, and there may be cases where there are almost no bubbles near the interface of the foamy layer B with the viscous liquid A.

[0020] The amount of exhaust that the pump 6 exhausts from inside the tank 3 to the outside and the time from time T0 to time T1 are set so that a foamy layer B with a liquid level L2 is formed. The liquid level L2 of the foamy layer B to be kept constant is set to a level that can be seen with the naked eye through a sight glass or the like (for example, about a few cm), or to a level where the liquid level L2 of the foamy layer B detected by the liquid level gauge 5 can be distinguished from the reference liquid level L0 (outside the error range of the liquid level gauge 5). The pump 6 is operated so that the liquid level L2 becomes the target liquid level. If the amount of discharge by the pump 6 per unit time is large, the time will be short, and if the amount of discharge is small, the time will be long. In any case, if the amount of discharge per unit time is appropriately set and exhaust is continued from time T0 to time T1, a negative pressure sufficient to form a foamy layer B with a liquid level L2 will be generated in the tank 3.

[0021] When liquid level L1 of foam layer B reaches liquid level L2 (time T1), control device 7 controls the amount of displacement by pump 6 so that the liquid level of foam layer B remains constant (liquid level L2) as shown from time T1 to time T2 in Fig. 3. Through this control, the bubbles formed near the interface between viscous liquid A and foam layer B and the bubbles that have burst at the top of foam layer B are in equilibrium, and while foam layer B as a whole is maintained at liquid level L2, gas from viscous liquid A is released into tank 3 through foam layer B. The gas released into tank 3 is exhausted to the outside of tank 3 by pump 6.

[0022] In order to keep the liquid level L1 of the foamy layer B constant (liquid level L2) from time T1 to time T2, the control device 7 detects the liquid level value of the foamy layer B with the liquid level gauge 5 and controls the pump 6 so that the liquid level value is kept constant. Alternatively, the output of the pump 6 from time T1 to time T2 may be determined (not necessarily constant, but may vary) and the pump 6 may be operated at the determined output depending on the elapsed time from the start of degassing. Such an output of the pump 6 can be obtained by conducting a test in advance. In addition to controlling the pump 6, a suction valve may be provided between the tank 3 and the pump 6, and the pressure in the tank 3 may be adjusted by controlling the opening of the suction valve to keep the liquid level of the foamy layer B constant.

[0023] As shown in Fig. 3 from time T2 to time T3, when the amount of gas contained in viscous liquid A decreases, the liquid level L1 of foam layer B becomes lower than the liquid level L2, even though pump 6 is operating. Then, as shown after time T3, when the gas contained in viscous liquid A is almost gone, foam layer B returns to the original reference liquid level L0. In other words, if foam layer B shrinks and disappears even though pump 6 is operating, the gas in the viscous liquid has been sufficiently degassed. Note that the amount of exhaust does not increase much during this period.

[0024] When the foamy layer B has shrunk to the reference liquid level L0 in this way, exhaust by the pump 6 is stopped. The foamy layer B having shrunk to the reference liquid level L0 means that the foamy layer B has almost disappeared and fallen below the reference liquid level L0. The foamy layer B having shrunk to the reference liquid level L0 is determined when the liquid level measured by the level gauge 5 falls below the reference liquid level L0. Alternatively, the pump 6 may be stopped based on the elapsed time required for the liquid level to fall below the reference liquid level L0. Specifically, the control device 7 stops the pump 6 when the time T3 has elapsed since the start of degassing (time T0). Such time T3 can be obtained by conducting a test in advance.

[0025] The control device 7 operates the agitator 4 after starting degassing, and agitates the viscous liquid A. There are no particular limitations on the timing of operating the agitator 4, or on the agitation speed and time. The agitator 4 agitates the viscous liquid A, and can generate vertical convection. Since the viscous liquid A has a high viscosity, the gas contained in the viscous liquid A does not easily move to the liquid surface. However, the agitation forcibly moves the gas in the viscous liquid A to the vicinity of the liquid surface and forms a foamy layer B, so that the viscous liquid A can be degassed more reliably.

[0026] As described above, the degassing system 1 of this embodiment forms a foamy layer B by placing the viscous liquid under negative pressure, and controls the discharge rate of the pump 6 to keep the foamy layer B constant. In order to maintain the foamy layer B, the pump 6 continues to discharge the liquid and is not stopped. Since discharge and stopping are not repeated in this way, the time required for degassing can be shortened, and less energy is required than if the pump 6 was started and stopped.

[0027] The pressure inside the tank 3 can be increased or decreased by operating or stopping the pump 6 or adjusting its output, thereby repeatedly forming and disappearing the foam layer B. In this case, it has been empirically and experimentally proven that it takes a long time to degas the viscous liquid. Compared to such a case, the present invention can perform degassing more quickly by maintaining the foam layer B constant.

[0028] Furthermore, if degassing were to be performed directly from the viscous liquid A by applying negative pressure without forming the foam layer B, the liquid level would only fluctuate slightly, making it difficult to determine whether the bubbles have been sufficiently degassed.

[0029] However, in the present invention, degassing is performed with foam layer B formed in viscous liquid A, and the degassing process is terminated when foam layer B disappears. The disappearance of foam layer B is synonymous with gas being sufficiently degassed from viscous liquid A, so the risk of gas remaining in viscous liquid A can be reduced. Furthermore, whether or not the relatively large foam layer B has disappeared is clear by visual inspection, and the change from the liquid level L2 to below the reference liquid level L0 can be detected without error by the liquid level gauge 5. Therefore, the disappearance of foam layer B can be detected more reliably by visual inspection or the liquid level gauge 5.

[0030] Second Embodiment 4 is a schematic diagram showing a tank in the degassing system according to embodiment 2. The tank 10 includes a first tank portion 11 and a second tank portion 12.

[0031] The first tank portion 11 is a part of the upper side of the tank 10, and the second tank portion 12 is a part of the lower side of the tank 10. In other words, the second tank portion 12 is provided below the first tank portion 11, and these are integrated to form one tank 10.

[0032] The first tank portion 11 is formed so that the upper side is cylindrical and the diameter of the lower side (the second tank portion 12 side) gradually decreases. The upper part of the first tank portion 11 is called a cylindrical portion 13, and the lower part is called a tapered portion 14.

[0033] The cylindrical portion 13 is formed in a substantially cylindrical shape and has a lid on the top. Although not shown in the figure, the lid on the top is provided with an opening that communicates with the inside of the tank 10, opening / closing means such as a lid or a valve for opening / closing the opening, and a group of devices such as a mechanism for opening and closing the opening / closing means.

[0034] The tapered portion 14 is formed in a tapered shape in which the diameter linearly decreases from the top to the bottom. The top of the tapered portion 14 is connected to the cylindrical portion 13, and the bottom is connected to the second tank portion 12.

[0035] The second tank portion 12 is formed in a substantially cylindrical shape, and the diameter of the second tank portion 12 is smaller than the diameter of the first tank portion 11 (cylindrical portion 13). The second tank portion 12 being formed in a cylindrical shape may include not only a portion formed in a cylindrical shape, but also a bottom portion whose diameter is gradually reduced. In the example shown in the figure, the second tank portion 12 is composed of an upper portion formed in a cylindrical shape and a tapered bottom portion whose diameter is gradually reduced from the top to the bottom.

[0036] Further, a take-out section (not shown) is provided at the bottom of the second tank section 12 for taking out a liquid product obtained by blending the ingredients stored in the tank 10. The take-out section is made up of an opening communicating with the inside of the tank 10, opening / closing means such as a lid or a valve for opening / closing the opening, and a group of devices such as a mechanism for opening and closing the opening / closing means.

[0037] 5 is a schematic diagram showing a state in which the tank in the degassing system according to embodiment 2 is in use. In the example shown in the figure, the volume of the second tank portion 12 is 30 L. The volume of the second tank portion 12 and the tapered portion 14 is 70 L. The volume of the tank 10 (the volume of the second tank portion 12, the tapered portion 14, and the cylindrical portion 13) is 600 L.

[0038] When preparing 30 L of a liquid product, various ingredients in amounts necessary to prepare the liquid product are charged into the tank 10, and the agitator 4 is operated. As a result, the agitator 4 agitates the ingredients in the second tank section 12, and 30 L of the liquid product is prepared.

[0039] When preparing 70 L of a liquid product, various ingredients in amounts necessary to prepare the liquid product are charged into the tank 10, and the agitator 4 is operated. As a result, the agitator 4 agitates the ingredients in the tapered section 14 and the second tank section 12, and 70 L of a liquid product is prepared.

[0040] When preparing 600 L of a liquid product, various ingredients in amounts necessary to prepare the liquid product are charged into the tank 10, and the agitator 4 is operated. As a result, the agitator 4 agitates the ingredients in the tank 10, and 600 L of the liquid product is prepared.

[0041] The tank 10 configured as described above can prepare a small volume of liquid product in the second tank portion 12, and prepare a large volume of liquid product in the first tank portion 11 and the second tank portion 12. That is, various volumes of liquid product from small to large volumes can be prepared with one tank 10. Of course, the volume of the liquid product to be prepared is not limited to 30L, 70L, or 600L.

[0042] Here, a case will be described in which a quantity of viscous liquid not exceeding the second tank portion 12 is stored in the second tank portion 12, and the gas in this viscous liquid is degassed. As in the first embodiment, a pump 6 (not shown) is operated to form a foamy layer B. The liquid level of this foamy layer B is made to exceed the second tank portion 12. By exceeding the second tank portion 12, a foamy layer B is formed from the second tank portion 12 to the first tank portion 11, which has a larger diameter.

[0043] The foamed layer B thus formed has an area equivalent to that of the first tank portion 11 in a plan view. In other words, it is larger than the area of ​​the second tank portion 12 in a plan view. In this way, the foamed layer B comes into contact with the space inside the tank 10 over a larger area compared to when the foamed layer B is contained in the second tank portion 12 (not shown), so that more air bubbles can be released quickly into the space inside the tank 10.

[0044] In this manner, the degassing system 1 of the present embodiment is capable of treating both large and small volumes of viscous liquid in one tank 10, and is capable of degassing a small volume of viscous liquid more quickly.

[0045] Third embodiment 6 is a schematic diagram showing a degassing system according to embodiment 3. The degassing system 1 of this embodiment includes a tank 20, a filter device 21, an ejection unit 22, a first pump 23, and a second pump 24.

[0046] The tank 20 has a discharge port provided at the bottom, and a first pipe 30 is provided to connect the discharge port to the filter device 21.

[0047] The filter device 21 has a primary side connected to the tank 20 via a first pipe 30, and a secondary side connected to the injection unit 22 via a second pipe 31. The filter device 21 captures gas contained in the viscous liquid A supplied from the tank 20. The filter device 21 may be of a dead-end type or a cross-flow type.

[0048] The ejection unit 22 is a device that ejects the viscous liquid sent from the second pipe 31 toward the inside of the tank 20. Specifically, a known shower ball type, roller ball type, push-out ball type, jet washer type, diffusion nozzle type, a 2D nozzle in which the nozzle itself rotates due to the reaction force of the ejected liquid, a 3D nozzle in which the nozzle itself rotates and revolves due to the reaction force of the ejected liquid, or the like can be used.

[0049] The second pipe 31 is connected to the tank 20 via a third pipe 32 that branches off midway. A portion of the viscous liquid is supplied to the inner surface of the tank 20 via the third pipe 32. A first pump 23 for pumping the viscous liquid is provided midway along the first pipe 30, and a second pump 24 for removing bubbles captured by the filter is connected to the primary side of the filter device 21.

[0050] Although not specifically shown, the degassing system 1 is provided with a pump for discharging gas from the tank 20, similar to that in the first embodiment.

[0051] The degassing system 1 of this embodiment is capable of degassing by forming a foam layer B by exhausting air using a pump, as in the first embodiment. The control device 7 (see FIG. 1) operates the first pump 23 to supply viscous liquid from the tank 20 to the filter device 21, causing the filter device 21 to remove gas (bubbles), and then causes the viscous liquid that has passed through the filter device 21 to be sprayed from the spray unit 22 into the inside of the tank 20. The viscous liquid sprayed from the spray unit 22 into the inside of the tank 20 falls on the foam layer B, promoting the destruction of the bubbles. This allows the gas in the foam layer B to be released more quickly into the internal space of the tank 20, thereby shortening the time required for degassing.

[0052] Other Embodiments Although each embodiment of the present invention has been described above, the basic configuration of the present invention is not limited to the above.

[0053] For example, in each embodiment, the raw material supply means 2 is provided, but this is not an essential component, and the raw material may be manually supplied to the tank 3. Furthermore, the stirring device 4 is not an essential component. The degassing is started after the raw material is charged, but this timing is not limited to this. For example, degassing may be started while the raw material is being charged. In the second embodiment, a two-tier tank 10 is exemplified, but the present invention is not limited to two tiers, and can also be applied to a tank with three or more tiers. [Explanation of symbols]

[0054] 1... degassing system, 2... raw material supply means, 3, 10, 20... tank, 4... stirring device, 5... liquid level gauge, 6... pump, 7... control device

Claims

1. A degassing system for degassing a viscous liquid having dissolved gas, comprising: A tank for storing the viscous liquid; A pump for exhausting gas from inside the tank; A control device for controlling the pump, The control device includes: The liquid level inside the tank when the pump is stopped is set as a reference liquid level, Operate the pump to evacuate the gas from the tank to form a foam layer on top of the viscous liquid; Controlling the amount of discharge by the pump so that the liquid level of the foam layer is constant; When the foam layer is reduced to the reference liquid level, the pump is stopped. A degassing system comprising:

2. 2. The degassing system of claim 1, The tank includes a first tank portion and a second tank portion provided below the first tank portion and having a smaller diameter than the first tank portion, The viscous liquid is stored in an amount not exceeding the second tank portion, The control device operates the pump to exhaust gas from the tank to form the foam layer over the second tank portion. A degassing system comprising:

3. 2. The degassing system of claim 1, an ejection unit that ejects the viscous liquid into the tank; a filter device having a primary side connected to the tank and a secondary side connected to the ejection unit, the filter device removing air bubbles contained in the viscous liquid sent from the tank to the ejection unit; The control device operates the pump to form the foam layer, while causing the viscous liquid to be sprayed from the spray unit through the filter device from the tank. A degassing system comprising:

4. The degassing system according to any one of claims 1 to 3, a stirring device that stirs the viscous liquid stored in the tank, The control device controls the agitator to agitate the inside of the tank while discharging the air by the pump. A degassing system comprising:

Images