JPH07100423A - Continuous deaeration apparatus - Google Patents

Abstract

PURPOSE:To provide a continuous deaeration apparatus removing air in coating material efficiently and continuously. CONSTITUTION:A continuous deaeration apparatus wherein air bubbles in coating material are removed in a vacuum chamber 11 is equipped with a transfer roll 13 transferring coating material into the vacuum chamber 11 from the outside, the discharge roll 14 discharging the coating material to the outside from the vacuum chamber, a deaeration roll means consisting of vacuum seal roll groups 15 sealing the spaces between those rolls 13, 14 and the wall of the vacuum chamber 11 and the coating material recovery scraper 17a recovering the coating material on the rolls discharging the coating material 12 from the vacuum chamber 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint defoaming device for defoaming contained air, which is applied to, for example, a coater of a steelmaking process machine, a coater of a papermaking machine, a printing machine and the like.

[0002]

2. Description of the Related Art FIG. 2 schematically shows a batch type vacuum defoaming apparatus according to the prior art. In the figure, reference numeral 01 is a vacuum chamber for defoaming the air in the paint 02, 03 is a paint pan for storing the paint 02 fed through a pump 04, and 05 is defoamed paint 06 after defoaming. , A paint tank, and 07, a coating device.

In the above-mentioned structure, the paint 02 is applied by a batch method.
In order to defoam, the following is done.

The paint 02 having air bubbles contained therein is a pump 0
4 and the valve 08, a specified amount is supplied into the vacuum chamber 01. After that, the valve 08 is closed and the air in the vacuum chamber 01 is exhausted by the vacuum pump 09 to place the paint 02 under a reduced pressure. At the same time, set the stirring device 010 to the motor 0
The paint 02 in the vacuum chamber 01 is driven by 11 to stir the paint 02 so that bubbles contained in the paint 02 can be easily removed. The defoamed paint 06 that has been defoamed through the above steps is recovered in the defoamed paint tank 05 by opening the valve 012 after returning the inside of the vacuum chamber 01 to the atmospheric pressure, and then via the pump 013. It is sent to the coating device 07.

[0005]

However, the conventional batch type defoaming apparatus described above has the following problems (1) to (3). (1) Only a specified amount of paint can be defoamed at one time, which hinders continuous operation. (2) The free interface (paint interface) area where bubbles escape from the paint is small, and bubbles are difficult to escape. (3) It is difficult to remove fine bubbles.

[0006]

The structure of a continuous defoaming device according to the present invention for solving the above problems is a continuous defoaming device for removing air bubbles mixed in a paint in a vacuum chamber, which is vacuumed from the atmosphere. Defoaming roll means consisting of a roll for transferring the paint into the room, a roll for discharging the paint from the vacuum chamber to the atmosphere, and a roll group for vacuum-sealing between these rolls and the vacuum chamber wall, and the vacuum chamber And a paint collecting means for collecting the paint on the roll for discharging the defoamed paint.

[0007]

According to the above construction, by using the defoaming roll means composed of a plurality of rolls for transferring and discharging the paint to the vacuum chamber, it is possible to continuously defoam the paint. Further, since the coating material on the roll surface is in the form of a thin film and is formed on the roll surface, the surface area per coating material volume is larger than that of the conventional method. For this reason, the ease with which bubbles in the paint escape is greatly improved compared to the conventional method. Furthermore, in the vacuum chamber, a shearing force acts on the paint as it is passed between the rolls. As a result, the paint and the bubbles in the paint are deformed, and the bubbles particularly near the free interface of the paint tend to escape. Further, by providing a plurality of stages of vacuum seal rolls at the entrance and exit of the vacuum chamber as a roll group, the pressure difference between before and after one seal roll is kept at an appropriate value for the paint flow rate transferred to and discharged from the vacuum chamber. I am trying. Furthermore, the defoaming paint can be efficiently collected by the paint collecting means.

[0008]

EXAMPLE A preferred example of the continuous defoaming apparatus according to the present invention will be described below.

FIG. 1 is a schematic view of a continuous defoaming apparatus according to this embodiment. As shown in the figure, the present apparatus is provided with a transfer roll 13 and a discharge roll 14 which are arranged at the entrance and exit of the vacuum chamber 11 to transfer and discharge the paint 12 containing air bubbles into the vacuum chamber.
And a plurality of stages of vacuum seal rolls 15 arranged between the roll surface for transferring the paint 12 from the atmosphere to the vacuum chamber 11 or discharging the paint 12 from the vacuum chamber 11 to the atmosphere and the outer wall of the vacuum chamber, A collection device 17 for collecting the defoamed paint by contacting the roll surface of the collection roll 16 located at the most downstream side of the roll group for collecting the paint on the roll surface discharged from the vacuum chamber 11 to the atmosphere. . In the figure, reference numeral 18 is a paint pan in which the paint 12 is filled and stored, 19 is a pickup roll for pumping the paint in the paint pan 18 to the transfer roll 13, and 20 is a vacuum pump for keeping the vacuum chamber 11 in a vacuum state. Reference numerals 21 and 21 respectively represent coating devices. Here, in this embodiment, the pickup roll 19 and the transfer roll 1
3, a defoaming roll means is formed from the discharge roll 14 and the vacuum seal roll group.

In the above structure, the unfoamed coating material 12 in the coating material pan 18 is pumped up by the pickup roll 19, stretched into a thin film at the transition portion between the transfer roll 13 and the pickup roll 19, and then transferred to the transfer roll 13. Transfers to the surface. Paint 12 transferred onto the surface of transfer roll 13
Enters the vacuum chamber 11 through the nip between the vacuum seal roll group 15 and the transfer roll 13. Here, the vacuum chamber 11
The flow rate of the coating material supplied to the inside is determined by the pressure difference between the front and rear of each seal roll, the peripheral wall of the roll, and the gap or nip pressure formed between the rolls.

The air bubbles contained in the paint 12 film on the transfer roll 13 that has entered the vacuum chamber 11 expands in volume according to the degree of vacuum of the vacuum chamber 11, and the paint film thickness is thin so that the bubbles are broken. The bubbles in the paint that have not been broken on the transfer roll 13 are subjected to shear deformation when the paint 12 is transferred from the transfer roll 13 onto the discharge roll 14 (or the transfer roll if there is a transfer roll) surface. To break the bubbles.

The defoamed paint 22 from which the air bubbles are removed by the above-described steps is discharged to the atmosphere through the vacuum seal roll group 15 by the rotation of the discharge roll 14.

Here, the paint discharge flow rate is determined by the transfer roll 14
The pressure gradient before and after the vacuum seal roll 15 is the reverse pressure gradient ([pressure at the seal roll outlet]>
[The pressure at the inlet of the seal roll]], so in order to balance the flow rate of the paint supplied by the transfer roll 13,
The peripheral speed of the discharge roll 14 is set to be higher than the peripheral speed of the transfer roll 13, or the number of stages of the vacuum seal roll group 15 is set larger than that on the transfer roll 13 side.

The defoamed coating material 22 discharged from the vacuum chamber 11 to the atmosphere by the discharge roll 14 is applied to the scraper 17a of the recovery means 17 arranged on the surface of the discharge roll 14 or in contact with the surface of the recovery roll 16. It is collected and supplied to the coating device 21 via the defoamed paint tank 23 and the pump 24.

Here, the recovery roll 16 disposed when recovering the defoamed paint 20 may reduce the paint recovery efficiency by the scraper 17a when the peripheral speed of the discharge roll 14 is high. In order to avoid that the surface of the discharge roll 14 may be scratched by the scraper 17a,
It is arranged as a puffer. If there is no such phenomenon as described above, the recovery roll 16 can be omitted.

[0016]

As described above with reference to the embodiments, the continuous deaerator according to the present invention has the following effects. It is possible to continuously defoam the paint. Even the defoaming of fine bubbles, which could not be defoamed by the conventional method, is possible. Therefore, the defoaming efficiency is increased. High defoaming efficiency can be obtained even for a high-viscosity paint that is difficult to defoam according to the conventional method. Since the time for which the paint is placed under vacuum is shorter than that of the conventional method, the deterioration of the paint is small. It is relatively easy to implement.

[Brief description of drawings]

FIG. 1 is a schematic view of a continuous defoaming device according to the present invention.

FIG. 2 is a schematic view of a vacuum degassing apparatus according to a conventional technique.

[Explanation of symbols]

 11 Vacuum Chamber 12 Paint 13 Transfer Roll 14 Discharge Roll 15 Vacuum Seal Roll Group 16 Recovery Roll 17 Recovery Device 18 Paint Pan 19 Pickup Roll 20 Vacuum Pump

Front Page Continuation (72) Yoichi Kai, Yoichi Kai, 6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd. Hiroshima Works (72) Yoshiaki Takeishi 4-53, Kitahama, Chuo-ku, Osaka City, Osaka Prefecture No. Sumitomo Metal Industries, Ltd. (72) Inventor Kenji Ikijima 4-53-3 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Sumitomo Metal Industries, Ltd.

Claims (1)

[Claims] 1. A continuous defoaming device for removing air bubbles mixed in paint in a vacuum chamber, comprising a roll for transferring the paint from the atmosphere into the vacuum chamber and a roll for discharging the paint from the vacuum chamber into the atmosphere. A defoaming roll means comprising a roll group for vacuum-sealing between these rolls and the vacuum chamber wall, and a paint collecting means for collecting the defoamed paint on the roll for discharging paint from the vacuum chamber, A continuous defoaming device characterized by: