JP2003001010A - Defoaming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a defoaming apparatus in which a vessel is small-sized, the power of a liquid feed pump is small, foam is separated in a short time and the excellent foam separation efficiency is exhibited even in a high viscous liquid. SOLUTION: In the defoaming apparatus 1 structured by a double structural vessel composed of an inside vessel 11 provided with a stirring blade 13 for stirring a liquid (b) inside and having a liquid supply port 16 on the bottom and an outside vessel 12 having a liquid discharge port 17 on the bottom and a liquid circulating means on the side surface, the liquid circulating mans is connected with a liquid circulating pipe 19 leading from the side surface lower part of the outside vessel 12 to the upper part of the inside vessel 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defoaming device for separating and removing bubbles in a printing ink, an adhesive, a coating liquid such as paint or a hydraulic fluid.

[0002]

2. Description of the Related Art When air bubbles are contained in various liquids such as printing ink, adhesive, varnish, hydraulic fluid, etc., these air bubbles cause product defects, equipment damage, noise, fluid flow measurement error, etc. Therefore, it is necessary to separate and remove air bubbles from the liquid, and various attempts have conventionally been made to remove air bubbles mixed in the liquid. There is a gravity method, etc.

The centrifugal separation type defoaming device utilizes centrifugal force. For example, as shown in FIG. 3, a bubble discharge port 18 is provided at the axial center of a conical container 31, and the same container 31 is provided.
Has a liquid supply port 16 on the upper side surface and a liquid discharge port 17 on the lower part of the container 31. When the liquid is introduced from the supply port 16 in the tangential direction of the inner surface of the container 31, the liquid swirls. , A bubble a with a low specific gravity due to its centrifugal force
Are collected in the center, floated and separated, and removed from the bubble removing port 18, so that only the remaining liquid flows out from the discharge port 17.

In the gravity type defoaming device, for example, as shown in FIG. 4, a liquid supply port 16 is provided in the lower portion of a container 31, and a liquid containing bubbles flowing from the supply port 16 is temporarily moved downward. Bucket 4 whose lower surface is inclined so that
1 is stored in the container 31, the discharge port 17 attached to the bucket 41 is projected to the outside of the container 31, and the bubbles a are floated on the liquid surface of the liquid contained in the container 31. The liquid containing bubbles a flowing in from 16 collides with the bottom of the bucket 41, changes its direction upwards, reverses and flows into the bucket 41, and the bubbles a are floated and removed from the bubble removal port 18, Only the remaining liquid is made to flow out from the discharge port 17.

[0005]

However, in the centrifugal separation type defoaming device, the centrifugal force generated by swirling the liquid is used to collect and separate the bubbles in the center. There was such a problem.
That is, if the liquid supply speed to the device is increased to swirl the liquid, the power of the supply pump increases, and since only the supply pump power gives centrifugal force to the vortex state. , The range in which centrifugal force is working in the device is narrow, and the device is not operating effectively. Also,
If the liquid viscosity is high, there are problems such as poor separation efficiency. On the other hand, in the gravity type defoaming device, the floating property of the bubbles is used, but a great amount of time is spent for the separation, the efficiency is poor, the container becomes large, and the separation efficiency is poor when the liquid viscosity is high, etc. There was a problem.

The present invention solves the above-mentioned problems of the prior art. The problem is that the container is not large, the power of the liquid supply pump is not large, and the bubbles can be separated in a short time. Another object of the present invention is to provide a defoaming device having a high efficiency of separating bubbles even with a highly viscous liquid.

[0007]

In order to achieve the above object in the present invention, first, in the invention of claim 1, a stirring blade for stirring a liquid is provided inside, and a liquid supply port is provided at a bottom portion. What is claimed is: 1. A defoaming device comprising a dual structure container having an inner container, an outer container having a liquid discharge port at the bottom, an air bubble removing means at the top, and a liquid circulating means at the side, the liquid circulating means being an outer container. The defoaming device is characterized in that the defoaming device is connected to the upper part of the inner container from the lower part of the side surface thereof by a liquid circulation path.

Further, according to the present invention of claim 2, a swash plate is installed on an upper edge of a side peripheral surface of the inner container so that an upper end thereof is in contact with the inner container. It is a thing.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. As shown in the side view of FIG. 1, the defoaming apparatus of the present invention is a defoaming apparatus 1 for defoaming a liquid containing bubbles, the container of which is an outer container 12 and an inner container 1.
It has a double structure of 1, and the inner container 1 of the double structure container
A stirring blade 13 for stirring the liquid b is provided inside 1, and a liquid supply port 16 is installed at the bottom. Further, the liquid outlet 17 is provided at the bottom of the outer container 12 of the double structure container.
Is provided, and a bubble discharge port 18 having a vacuum pump 14 is provided at an upper portion thereof, and a liquid circulation means by a liquid circulation pump 15 is provided at a side surface of the outer container 12.
The defoaming device 1 is connected by a liquid circulation pipe 19 that leads from the lower part of the side surface to the upper part of the inner container 11.

As shown in the side view of FIG. 2, the defoaming device of the present invention has a defoaming device in which a swash plate 21 is installed, for example, at the upper edge of the side surface of the inner container 11 so that its upper end 21a is in contact. The device 1.

Therefore, in the defoaming apparatus 1, as shown in FIG. 1, the liquid b flowing from the liquid supply port 16 is stored in the inner container 11 of the apparatus main body. The stored liquid is a stirring blade 1.
A vortex is generated by being agitated in 3, and air bubbles having a low specific gravity are collected in the central portion of the inner container 11, and the defoamed liquid is collected near the upper edge of the inner container 11. At this time, the bubbles collected in the central portion of the inner container 11 are sucked by the vacuum pump 14 from the bubble discharge port 18 and discharged. The inner container 11 is filled with the inflowing liquid, overflows from the edge of the inner container 11, and is stored in the outer container 12. The overflowed liquid at this time has already been defoamed and flows out from the liquid discharge port 17.

At the start of the defoaming operation, when the liquid b overflows from the inner container 11, since there is no liquid in the outer container 12, the liquid b falls or scatters to generate bubbles, or a vacuum is generated. Since the defoaming may be insufficient due to the vacuum condition not being met by the pump 14, the work of returning the incompletely defoamed liquid to the inner container 11 again through the liquid circulation pipe 19 using the circulation pump 15. In some cases it may cost.

Further, as shown in FIG. 2, the swash plate 21 is arranged so that the upper end 21a thereof is in contact with the upper end edge of the outer surface of the inner container 11.
By installing, it is possible to prevent bubbles from being regenerated by dropping or scattering of the liquid b, and to improve the defoaming efficiency.

The stirring blade 13 for stirring the liquid in the inner container 11 may have any shape, number, and rotation speed as long as the liquid swirls and bubbles are collected in the central portion of the inner container 11. Not something to do.

A vacuum pump 14 for discharging air bubbles
There are methods such as an oil rotary type, a dry type, and a diaphragm type, and any type may be used as long as the inside of the container can be vacuumed.

As the liquid circulation pump 15, a gear type, a diaphragm type, a sine type, a snake type pump or the like can be used.

[0017]

EXAMPLES Next, the present invention will be specifically described with reference to examples. <Example 1> Coating liquid defoamed by using a defoaming device 1 (without a swash plate) as shown in FIG. 1: WTCC257 (acrylic aqueous coating liquid, viscosity 8000 mPa · s, specific gravity 1.3)
6, manufactured by Toppan Printing Co., Ltd. with a knife coater to a thickness of 25
A coated sheet was formed on a polyethylene terephthalate film having a thickness of 100 μm under the condition of a coating amount of 100 g / m ² , the coated surface state and the specific gravity were measured, and the results are shown in Table 1.

Example 2 As a defoaming device, a coated sheet was prepared in the same manner as in Example 1 except that a swash plate 21 was added to the outer peripheral surface of the inner container 11 as shown in FIG. The obtained sheet was evaluated in the same manner as in Example 1,
The results are shown in Table 1.

Comparative Example 1 A coated sheet was prepared in the same manner as in Example 1 except that the stirring blade 13 shown in FIG. 1 and the swash plate 21 shown in FIG. 2 were omitted as the defoaming device. The obtained sheet was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0020]

[Table 1]

From Table 1 above, both the defoaming device used in Example 1 (with stirring blade) and the defoaming device used in Example 2 (having stirring blade and swash plate) were forced by the stirring blade. Since the bubbles can be collected in the center of the container, the bubbles in the coating liquid can be continuously removed regardless of the viscosity of the coating liquid. The defoaming device in Example 2 to which the swash plate was added had excellent defoaming efficiency. On the other hand, a large number of pinholes were observed in the coating film of the sheet of Comparative Example 1 having neither a stirring blade nor a swash plate.

[0022]

Since the present invention has the above-mentioned constitution, it has the following effects. That is, an inner container having a stirring blade for stirring the liquid inside, having a liquid supply port at the bottom, and an outer container having a liquid discharge port at the bottom, a bubble removing means at the top and a liquid circulating means at the side It is a double structure container,
By using the defoaming device in which the liquid circulation means is connected by the liquid circulation path leading from the lower part of the side surface of the outer container to the upper part of the inner container, it is possible to forcibly collect air bubbles in the center part of the container. Bubbles in the coating liquid can be removed continuously regardless of the viscosity, and by installing a swash plate at the upper edge of the side peripheral surface of the inner container, the liquid overflowing from the inner container can be prevented from falling or falling. It is possible to provide a defoaming device that can prevent bubbles from being regenerated due to scattering and have an effect of improving defoaming efficiency.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an embodiment of a defoaming device of the present invention.

FIG. 2 is a schematic side view showing another embodiment of the defoaming device of the present invention.

FIG. 3 is a schematic side view showing an example of a conventional centrifugal defoaming device.

FIG. 4 is a schematic side view showing an example of a conventional gravity type defoaming apparatus.

[Explanation of symbols]

1 Defoaming device 11 ... Inner container 12 ... Outer container 13 ... Stirring blade 14 ... Vacuum pump 15 Circulation pump 16 ... Liquid supply port 17 Liquid outlet 18 ... Bubble outlet 19 Liquid circulation pipe 21 ... Swash plate 21a ... the upper end of the swash plate 31 ... Cylindrical container 41 ... bucket a ... bubble b ... liquid

Claims (2)

[Claims] 1. An inner container having a stirring blade for stirring a liquid therein, a liquid supply port at a bottom portion, a liquid discharge port at a bottom portion, a bubble removing means at an upper portion, and a liquid circulating means at a side surface. A defoaming device consisting of a double structure container with an outer container having, wherein the liquid circulating means is connected by a liquid circulation path leading from a lower part of a side surface of the outer container to an upper part of the inner container. apparatus. 2. The defoaming device according to claim 1, wherein a swash plate is installed on an upper edge of a side peripheral surface of the inner container so that an upper end thereof is in contact with the inner container.