DE9105215U1 - Device for adding air bubbles into a single or multi-component mixture of a liquid medium, in particular into a viscous adhesive - Google Patents

Description

Device for adding air bubbles to a single or multi-component mixture of a liquid medium, in particular in a viscous adhesive

The present innovation relates to a device according to the generic term of claim 1. When bonding single or multi-component mixtures, there is the problem that air bubbles must be introduced into the adhesive in order to ensure that the adhesive foams up. It is known to date that this air loading of the medium can be carried out in a container where this medium is stored and, if necessary, stirred. When the medium is stirred in the container, the corresponding air loading is carried out via a separate air valve and an associated air line. The disadvantage of air loading in the container, however, is that dosing the amount of air to be supplied is very difficult. As a rule, a constant air loading cannot be achieved; in addition, inaccuracies also arise due to the fact that the mixture circulates and is returned from the container to the container via a bypass valve on the mixing head.

It has also become known to air-charge such component mixtures, in which the air is charged directly at the mixing head itself, with the air being introduced into the mixing head via an adjustable air valve. The disadvantage of this type of air-charging, however, is that the air-charging is also very inaccurate, due to the small volume of the component in the mixing chamber and the inaccuracy of the metering valve.

Furthermore, there is the disadvantage that with such an air valve only bubbles of relatively large size can be introduced into the mixture, but it is not possible to generate so-called microbubbles in the mixture.

The present innovation is therefore based on the task of developing a device of the type mentioned at the beginning in such a way that microbubbles can be introduced into the mixture in a simple and precise manner in finely dosed and reproducible quantities.

To solve the problem posed, the innovation is characterized by the technical teaching of claim 1.

An essential feature of the present invention is that, according to the innovation, an air connection is now directly connected to a channel of the mixing chamber without the interposition of an air or metering valve and that a sintered body of a certain pore size is arranged in this connecting channel.

It has now surprisingly been found that - if one uses a relatively fine-pored sintered body - this sintered body does not tend to become clogged and that, on the contrary, the surface of the sintered body that is in contact with the medium - which can be relatively small - acts as an air-releasing surface into the medium, whereby fine microbubbles are introduced into the medium via this air-releasing surface.

The prerequisite for this is that the air pressure at the air connection piece is greater than the medium pressure in the mixing chamber in order to ensure that air is mixed in at all.

The sintered body also acts as a shut-off valve, i.e. fine air bubbles can escape; however, the pore size of the sintered body is selected in such a way that the medium cannot penetrate into the pores of the sintered body and thus clog it.

Several advantages are achieved simultaneously, namely a finely dosed, reproducible addition of a precisely measured

Amount of air into the medium, whereby the amount of air to be introduced is regulated by an air flow meter and a corresponding valve and the sintered body also ensures that the air-emitting surface in the mixing chamber does not become clogged with the medium.

In this case, a cylindrical shape is preferred for the sintered body, whereby the sintered body consists of two cylinders lying one behind the other and connected to one another and having a different diameter.

The first, narrower cylinder dips into the medium of the mixing chamber with its front surface as an air-releasing surface, while the front side of the sintered body with the larger diameter is exposed to the air.

In another embodiment of the present innovation, it is provided that the sintered body consists of a uniform, continuous and non-stepped cylinder body.

The air loading takes place in the mixing chamber, whereby the mixing chamber is in turn connected to the mixing head via its central recess. A rotary-driven stirrer runs into the mixing head and the two components "α component" and "B component" are fed into the mixing head area.

In axial extension to the central recess, the recess narrows to a nozzle opening through which the shot is then fired.

In a preferred embodiment, a medium pressure of 0 to 10 bar is used, depending on whether the adhesive is to be injected into a tool mold or released without pressure via the mixing head.

When working without pressure, an air pressure of more than 0

- 6 bar up to a limit of about 10 bar.

Depending on the diameter of the sintered body, i.e. the area of the air-releasing surface of the sintered body, more or fewer microbeads are introduced into the medium. The introduction of the microbeads also depends on the air pressure used and the amount of air supplied.

The preferred material for such a sintered body is aluminum sintered body with pore sizes of 20 to 200 micrometers. A material viscosity of 50 - 1,000,000 mPas is required.

The subject matter of the present innovation arises not only from the subject matter of the individual patent claims, but also from the combination of the individual patent claims with one another. All information and features disclosed in the documents - including the summary, in particular the spatial design shown in the drawings - are claimed as essential to the invention insofar as they are new individually or in combination compared to the prior art.

In the following, the innovation is explained in more detail using drawings that only show one way of carrying out the invention. The drawings and their descriptions reveal further features and advantages of the innovation that are essential to the invention.

Show it:

Figure 1: Section through a mixing chamber segment with attached air nozzle and sintered body;

Figure 2: Section through the mixing chamber segment according to Figure 1.

According to Figures 1 and 2, the mixing chamber segment 1 consists of a rectangular body with a central recess 2, which merges radially outward into smaller recesses 3.

Perpendicular to the drawing plane of Figure 1, another segment sits on this mixing chamber segment, namely the mixing head, which - not shown in the drawing - has the rotary-driven stirrer, the component inlets and the component valve.

A connection block 5 is flanged to one side of the mixing chamber segment 1, into which an air connection 4 opens. The air connection 4 opens into a connection channel 11, in the course of which a sintered body 6 is arranged. In a preferred embodiment, the sintered body 6 consists of a cylindrical part 7 with a larger diameter compared to a smaller, cylindrical part 8 attached to it in one piece.

The cylindrical part 8 engages in a connection channel 12, which connection channel forms the connection between the upper connection channel 11 and the mixing chamber 13 containing the medium. Here, the front surface of the smaller part 8 of the sintered body 6 forms an air-releasing surface 10, which protrudes directly into the medium flow and is touched by it.

If a corresponding air pressure is now applied to the air connection 4, then the air flows through the upper surface 9 of the sintered body 6 and exits at the lower, air-emitting surface 10 and thus into the medium arranged in the mixing chamber 13. This results in a fine bead of air being introduced into the medium within the mixing chamber, whereby microbeads are produced.

The pearl size of the microbeads is determined on the one hand by the pore size of the sintered body, which pore size should be chosen as small as possible in order to produce the smallest possible pearls and it is also determined

from the viscosity of the medium used.

According to Figure 2, a further segment 14 is attached to the mixing chamber segment 1, which can have the outlet nozzle in its central recess 15.

The embodiment described above is merely a preferred embodiment, with many modifications possible. The mixing chamber can consist of a single part, i.e. not of different segments 1, 14; it is also possible to form the sintered body 6 as a continuous cylindrical body without forming a larger part 7 and a smaller part 8.

It is also conceivable to manufacture the mixing chamber directly from the sintered material, whereby the escape of air via the mixing chamber’s outer surfaces is prevented by a suitable seal.

The mixing chamber described here is suitable for processing single or multi-component mixtures, whereby all media are known, regardless of whether they are highly or low-viscosity. Instead of introducing air in the form of microbeads into the medium, it is intended that other gases can also be introduced, such as noble gases and the like.

1 mixing chamber segment

2 recess

3 Recess

4 Air connection

5 Connection block

6 sintered bodies

7 Part

8 Part

9 Area (top)

10 Area (bottom)

11 Connection channel

12 "

13 Mixing chamber

14 Segment

15 Recess

- 9 DRAWING LEGEND

Claims (5)

Applicant: EDF-Klebetechnik Gesellschaft m.b.H., Allgäustraße 3, A-6912 Hörbranz, Austria Protection claims 1. Device for mixing air bubbles into a single or multi-component mixture of a liquid medium, in particular into a viscous adhesive, whereby the air or another gas is introduced into the mixing head, characterized in that an air connection (4) opens directly into the mixing chamber (13) via a connection channel (11, 12) and that a sintered body (6) is arranged in a sealing manner in this connection channel, which is exposed to the air on one side and is in contact with the medium on the other side. Telephone: Telex: Facsimile / Fax: » Lindau (0 83 82) 5 43 74(patent-d) +49-8382-7 80 27 7 80 25 Telegram address: patri ^: lindau Bank accounts: Postal checking account Bayer. Vereinsbank Lindau (B) No. 1257 110 (bank code 735 200 74) Munich 414 848-808 Hypo - Bank Lindau (B) No. 66 70 - 326 843 (bank code 733 204 42) (bank code 700100 80) Volksbank Lindau (8* No. 51 222 000 (bank code 735 901 20) 2. Device according to claim 1, characterized in that the sintered body (6) consists of a cylindrical part with two different diameters (7, 8), of which the larger cylindrical part (7) is supplied with air and the smaller cylindrical part (8) is in contact with the medium. 3. Device according to claim 1 or 2, characterized in that only the front sides (surfaces 9, 10) of the sintered body (6) are exposed to the air or the medium. 4. Device according to one of claims 1 - 3, characterized in that the material of the sintered body (6) is an aluminum sintered material. 5. Device according to one of claims 1 - 4, characterized in that the pore size of the sintered body (6) is in the range between 20 - 200 micrometers.