FI66125B - ANORDNING FOER DISPERGERING AV POLYMERER - Google Patents

Description

1 66125

This invention relates to a polymer dispersing device.

In industry, so-called polymer solutions are used for various purposes. They are aqueous solutions of viscous high molecular weight organic substances made by mixing a dry polymer with water. In order to avoid the formation of lumps, so-called "fish eyes", the polymer should be mixed with the water in a fine form, and a water jet pump, an ejector, which is allowed to absorb the dry fine polymer, is commonly used for this purpose. However, the difficulty has been e.g. the fact that inside the ejector to the boundary where the hot water jet and the polymer meet, the wetting polymer adheres and gradually causes the ejector to become clogged, so that the use must be interrupted for cleaning. The susceptibility of the ejector to clogging thus prevents its use in equipment for the automatic and continuous preparation of a polymer solution.

It is therefore an object of the present invention to provide an ejector-type dispersing device which does not have the above-mentioned difficulties and which can thus be used for the continuous and automatic preparation of polymer solutions.

The dispersing device according to the invention thus comprises a water tank provided with a pressurized water supply line and annular split nozzles at one end of the tank, a polymer-air mixture feed pipe passing through the tank in the middle of the spray nozzles, and a nozzle is characterized in that the container has a channel surrounding the supply pipe, the diameter of which is larger than the outer diameter of the supply pipe, and that the downcomer is separated from the container by an air gap.

2 66125

According to a preferred embodiment of the invention, the mouth of the polymer-air mixture supply pipe may be slightly constricted, and the container channel extension may be an annular lip surrounding the polymer-air mixture supply pipe.

The invention is described in more detail below with reference to an application example of a dispersing device according to the invention schematically shown in the accompanying drawing.

In the drawing, 1 means a vertical cylindrical water tank provided with a through-passage 2 at its center, a pressurized water supply pipe 3 and a plurality of annular nozzles 4 circularly arranged around the mouth of the duct. In the duct 2 there is a polymer-air mixture feed pipe 6 there is free space everywhere. In the embodiment shown, the mouth opening of the supply pipe 6 at approximately the lower end of the container 1 is slightly constricted and surrounded by an annular lip 7 as an extension of the channel 2. Below the container 1 there is a downcomer 8 having a diameter substantially corresponding to the outer diameter of the container 1. Below the downcomer 8 there is a tank 10 into which the polymer solution formed collects and from which it is discharged via a line 11. The lower end of the downcomer 8 is located above the liquid surface of the tank 10 so that the air flowing through the downcomer can escape freely.

The operation of the dispersing device is as follows.

The pressurized water is led to a tank 1, from where it is sprayed from the nozzles 4 in fine jets into the downcomer 8, as indicated by the arrows 5. The spraying of water from the nozzles 4 into the downcomer 8 causes an air flow on the one hand through the free space of the duct 2 and on the other hand through the air gap 9 between the tank 1 and the downcomer 8, as indicated by the dashed arrows. Along the supply pipe 6, a fine mixture of polymer and air is introduced into the downcomer 8 outside the device, for example in a compressed air ejector, from which the water jets 5 divided into fine droplets 66125 The device does not form a boundary between the water and the polymer-air mixture on a solid surface because there is pure air between them, so that the contact between the water and the polymer takes place in the gas phase. Due to the air flowing through the duct 2 outside the supply pipe 6 and from the air gap 9, water cannot splash into the mouth of the supply pipe 6. The constriction of the mouth of the supply pipe 6 also advantageously affects the flow conditions, and the annular lip 7 protects the mouth of the supply pipe 5. However, the throttling of the supply pipe 6 and the lip 7 are not necessary for the safe operation of the device.

From the downcomer 8, the solution enters the tank 10, allowing air to escape from the downcomer, as indicated by the dashed arrows.

Claims (3)

66125 Polymer dispersing device comprising a water tank (1) provided with a pressurized water supply line (3) and annular split spray nozzles (4) at one end of the tank, a polymer air mixture passing through the tank (1) passing through the tank (1) in the middle of the spray nozzles (4) (6), and a downcomer (8) extending into the container, into which the spray nozzles (4) and the supply pipe (6) open, characterized in that the container (1) has a channel (2) surrounding the supply pipe (6) with a diameter of the supply pipe (6). ) larger than the outer diameter, and that the downcomer (8) is separated from the tank (1) by an air gap (9). Device according to Claim 1, characterized in that the mouth of the polymer-air mixture supply pipe (6) is slightly constricted. Device according to Claim 1 or 2, characterized in that the extension of the channel (2) of the container (1) is an annular lip (7) surrounding the mouth of the polymer-air mixture supply pipe (6).