GB2124096A - Mixing apparatus - Google Patents

Abstract

Mixing apparatus for paint comprises a container 10 which is generally conical 30 at its lower portion so that it can be used to make quantities which is particularly small in relation to the total size of the container. A slow speed agitator 12 is provided together with at least one high speed agitator 18, the combined action of the agitators effecting thorough mixing of the materials whatever the size of the batch. <IMAGE>

Description

SPECIFICATION Dispersal apparatus This invention relates to mixing and dispersal apparatus for us, for example, in the manufacture of paint.

Conventional dispersal apparatus comprises a cylindrical vessel for containing the solvent, pigment and the like which are to be mixed and dispersed.

The axis of the cylinder extends vertically, and the upper end is closed by a removable lid. The lower end is usually of very shallow conicity, apex up. A number of agitators extend into the container. In a small size (volume) apparatus one or two agitators may be used, but in large size apparatus it is usual to have a low speed agitator which serves the purpose of causing a gentle circulatory motion of the pot content together with one or more relatively small diameter high speed agitators which effect mixing and dispersal locally within the pot. Hence, the high speed agitator carries out the required mixing and dispersal on a small part of the pot contents, and the low speed agitator brings unmixed components to the high speed agitator and removes mixed components from the high speed agitator, until the mixing and dispersal is complete.

It is conventional to manufacture this dispersal apparatus in a whole range of sizes. But it often happens that a required batch represents only a small percentage of the nominal capacity of an available apparatus. Depending upon the design details, the minimum quantity which can be dealt with is likely to be of the order of 20% of the nominal capacity, because of the need to have at least the high speed agitator fully immersed.

The object of the invention is to provide improved apparatus which is more versatile in this respect.

In accordance with the invention considered broadly, the container for a mixing and dispersing apparatus has at least the lower part thereof tapering to a minimum dimension at the lowermost portion.

Preferably the container includes a conical lower portion and a cylindrical upper portion.

Preferably also the conical lower portion represents 50% of the vertical height, and the maximum diameter may be about two thirds of the total height; according to the inventor's calculations, it will be possible to use such apparatus efficiently with a minimum content possibly as low as 4% of the nominal content.

The invention is more particularly illustrated with reference to the accompanying drawings in which: Figure 1 is a sectional and somewhat diagrammatic elevation of a prior art mixing apparatus; and Figure 2 is a view similar to Figure 1 of an apparatus according to the invention, as comparison with the prior art arrangement.

Referring to the drawings, the apparatus in both Figures 1 and 2 comprises a pot or container and a low speed agitator comprising one or more blades 12 which closely conform to the side wall and space ofthe container and which are driven by an axial shaft 14 extending through a bottom bearing with appropriate seals and driven from a motor 16 via a belt chain or other transmission system.

The apparatus also comprises one or more highspeed agitators 18 on separate shafts 20 which extend downwardly from drive motors 22 located above the container, with a jacking system 24 for lifting and lowering the highspeed agitator. The container is closed by a lid 26 and an outlet port near the base of the container is controlled by valve system 28.

It will be appreciated that in the arrangement shown in Figure 1,the minimum volume for satisfactory mixing is that which will completely immerse the highspeed agitator 18.

In the arrangement according to the invention shown in Figure 2, the proportions of the container are varied as mentioned hereinbefore. In addition, the highspeed agitator is located so that at its lowermost position approximates to the container axis so that it is capable of immersion when the container holds a minimum volume of liquid. As seen in the drawings, the frusto-conical lower portion 30 represents substantially half of the vertical height of the container and the diameter of the upper and cylindrical portion is about two thirds of the total height.

1. Mixing and dispersal apparatus comprises a container having a removable lid, a slow speed agitator, and at least one high speed agitator, the container having at least a lower part tapering to a minimum dimension at the lowermost portion.

2. Apparatus as claimed in Claim 1 wherein there is a conical orfrusto-conical lower portion and a cylindrical upper portion, and the slow speed agitator sweeps the wall of at least the lower portion.

3. Apparatus as claimed in Claim 2 wherein the lower portion represents 50% of the vertical height.

4. Apparatus as claimed in any preceding claim wherein the maximum diameter is about two thirds of the total height.

5. Apparatus as claimed in any preceding claim wherein the or a high speed agitator extends to the axis of the container.

6. Mixing and dispersing apparatus substantially as described with reference to Figure 2 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Dispersal apparatus This invention relates to mixing and dispersal apparatus for us, for example, in the manufacture of paint. Conventional dispersal apparatus comprises a cylindrical vessel for containing the solvent, pigment and the like which are to be mixed and dispersed. The axis of the cylinder extends vertically, and the upper end is closed by a removable lid. The lower end is usually of very shallow conicity, apex up. A number of agitators extend into the container. In a small size (volume) apparatus one or two agitators may be used, but in large size apparatus it is usual to have a low speed agitator which serves the purpose of causing a gentle circulatory motion of the pot content together with one or more relatively small diameter high speed agitators which effect mixing and dispersal locally within the pot. Hence, the high speed agitator carries out the required mixing and dispersal on a small part of the pot contents, and the low speed agitator brings unmixed components to the high speed agitator and removes mixed components from the high speed agitator, until the mixing and dispersal is complete. It is conventional to manufacture this dispersal apparatus in a whole range of sizes. But it often happens that a required batch represents only a small percentage of the nominal capacity of an available apparatus. Depending upon the design details, the minimum quantity which can be dealt with is likely to be of the order of 20% of the nominal capacity, because of the need to have at least the high speed agitator fully immersed. The object of the invention is to provide improved apparatus which is more versatile in this respect. In accordance with the invention considered broadly, the container for a mixing and dispersing apparatus has at least the lower part thereof tapering to a minimum dimension at the lowermost portion. Preferably the container includes a conical lower portion and a cylindrical upper portion. Preferably also the conical lower portion represents 50% of the vertical height, and the maximum diameter may be about two thirds of the total height; according to the inventor's calculations, it will be possible to use such apparatus efficiently with a minimum content possibly as low as 4% of the nominal content. The invention is more particularly illustrated with reference to the accompanying drawings in which: Figure 1 is a sectional and somewhat diagrammatic elevation of a prior art mixing apparatus; and Figure 2 is a view similar to Figure 1 of an apparatus according to the invention, as comparison with the prior art arrangement. Referring to the drawings, the apparatus in both Figures 1 and 2 comprises a pot or container and a low speed agitator comprising one or more blades 12 which closely conform to the side wall and space ofthe container and which are driven by an axial shaft 14 extending through a bottom bearing with appropriate seals and driven from a motor 16 via a belt chain or other transmission system. The apparatus also comprises one or more highspeed agitators 18 on separate shafts 20 which extend downwardly from drive motors 22 located above the container, with a jacking system 24 for lifting and lowering the highspeed agitator. The container is closed by a lid 26 and an outlet port near the base of the container is controlled by valve system 28. It will be appreciated that in the arrangement shown in Figure 1,the minimum volume for satisfactory mixing is that which will completely immerse the highspeed agitator 18. In the arrangement according to the invention shown in Figure 2, the proportions of the container are varied as mentioned hereinbefore. In addition, the highspeed agitator is located so that at its lowermost position approximates to the container axis so that it is capable of immersion when the container holds a minimum volume of liquid. As seen in the drawings, the frusto-conical lower portion 30 represents substantially half of the vertical height of the container and the diameter of the upper and cylindrical portion is about two thirds of the total height. CLAIMS

1. Mixing and dispersal apparatus comprises a container having a removable lid, a slow speed agitator, and at least one high speed agitator, the container having at least a lower part tapering to a minimum dimension at the lowermost portion.

2. Apparatus as claimed in Claim 1 wherein there is a conical orfrusto-conical lower portion and a cylindrical upper portion, and the slow speed agitator sweeps the wall of at least the lower portion.

3. Apparatus as claimed in Claim 2 wherein the lower portion represents 50% of the vertical height.

4. Apparatus as claimed in any preceding claim wherein the maximum diameter is about two thirds of the total height.

5. Apparatus as claimed in any preceding claim wherein the or a high speed agitator extends to the axis of the container.

6. Mixing and dispersing apparatus substantially as described with reference to Figure 2 of the accompanying drawings.