GB2211435A

GB2211435A - A rotary mixing apparatus

Info

Publication number: GB2211435A
Application number: GB8824706A
Authority: GB
Inventors: Raolo Benvenuto Guisti
Original assignee: T Giusti and Son Ltd
Current assignee: T Giusti and Son Ltd
Priority date: 1987-10-22
Filing date: 1988-10-21
Publication date: 1989-07-05
Anticipated expiration: 2008-10-21
Also published as: GB8824706D0; GB2211435B; GB8724786D0

Abstract

A rotary mixing apparatus comprises a vessel (1) for containing materials to be processed, the vessel having a substantially hemi-spherical lower portion through which two co-axial shafts (20, 27) pass at an inclination to the vertical. The first shaft (20) drives rotationally a C-shaped agitator having arms (11, 12) mounted within the lower portion of the vessel so that, upon rotation by the first shaft, the agitator passes over substantially the entire inner surface of the lower portion of the vessel. The second shaft (27) drives rotationally an emulsifier rotor element (33) for effecting emulsification of the material to be processed. <IMAGE>

Description

DESCRIPTION OF INVENTION Improvements in or relating to a rotary mixing apparatus THIS INVENTION relates to a rotary mixing apparatus for use, for example, in the processing of materials in the food, pharmaceutical and cosmetic industry.

In these industries, it is necessary to mix together various liquids and solids and this is normally carried out in a mixing vessel provided with a rotating agitator.

U.K. Patent Specification No. 2116059 discloses a mixing apparatus comprising a container for receiving material to be mixed, the container having a substantially hemi-spherical lower portion and an upper portion. A substantially C-shaped agitator is mounted in the lower portion of the vessel in order that said agitator is rotatable in the vessel about an axis inclined to the vertical and which intersects the lower portion of the vessel. The C-shaped agitator is connected, by a shaft which passes through the hemispherical lower portion of the vessel, to drive means for rotating the agitator about the said axis. This arrangement ensures that when the agitator is rotated in use of the apparatus, said agitator passes adjacent substantially the entire inner surface of the lower portion of the vessel. The agitator is provided with scrapers which scrape this entire inner surface.The agitator is operable to lift material from the lower portion of the vessel to the upper portion thereof, to ensure a rapid and thorough mixing.

The mixing apparatus disclosed also includes an emulsifier mounted at the upper portion of the vessel with a rotary head located at the end of a drive shaft extending from the upper portion of the vessel towards the lower portion thereof. The rotary head, in use, is located adjacent the position at which the agitator is rotatably mounted to the lower portion.

The emulsifier, although operating satisfactorily, is inconveniently located, since it is over the open upper mouth of the mixing vessel through which materials are introduced to and removed from said mixing vessel.

Aceording to the present invention there is provided a vessel for containing materials to be processed, the vessel having a lower portion through which two co-axial shafts pass, the first being adapted to drive rotationally an agitator within the vessel, and the second shaft being adapted to drive rotationally an emulsifier rotor element for effecting emulsification of the material to be processed.

Conveniently the emulsifier rotor co-operates with an emulsifier stator carried on said agitator. The stator is provided with a plurality of concentric rows of upstanding teeth and the emulsifier rotor element is provided with a plurality of concentric rows of annular grooves such that, when the rotor is in position, the rows of teeth on the stator are interposed in the annular grooves provided on the emulsifier rotor element.

Preferably the first shaft is a hollow shaft, the second shaft passes therethrough and a seal is provided within the mixing vessel between the second shaft and the end of the first shaft located within the vessel.

Advantageously the apparatus further comprises two motors, the first adapted to drive the first shaft and the second adapted to drive the second shaft. The motor which drives the second shaft being adapted to drive the second shaft at a greater speed than the motor which drives the first shaft.

Conveniently the lower portion of the vessel is substantially hemi-spherical and the agitator is partcircular, being mounted in the lower portion of the vessel so as to be rotatable in the vessel about an axis inclined to the vertical.

Preferably the part-circular agitator is substantially C-shaped comprising a first arm and a second arm and the said inclined axis extends through the agitator in order that the first arm of the agitator is disposed on one side of the axis and the second arm is disposed on the other side of the axis.

According to a second aspect of the present invention there is provided a method of mixing materials comprising the steps of introducing the materials into the vessel of a rotary mixing apparatus, the vessel having a lower portion through which two co-axial shafts pass, the first carrying an agitator and the second carrying an emulsifier rotor element within the vessel, the method comprising the further steps of rotationally driving said first and second shafts, thus driving the agitator and the emulsifier to mix and emulsify said materials.

The present invention also provides a material when mixed in accordance with a method as described above.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which: FIGURE 1 is a view of a rotary mixing apparatus of the prior art design; FIGURE 2 is a part sectional view of a rotary mixing apparatus embodying the present invention.

Figure 3 is an enlarged view of an emulsifier of the apparatus of Figure 2.

Referring now to the drawings, Figure 1 shows a stainless steel mixing vessel 1 having a hemispherical lower portion 2 and a cylindrical upper portion 3. A lid 4 may or may not be necessary depending on the product to be processed in the mixing vessel 1.

The lower portion 2 of the vessel is provided with an external jacket 5 through which a heating or cooling medium may be circulated to heat or cool any material within the mixing vessel 1 during mixing. The container is supported on spaced legs 6, two of which are illustrated.

A motor 7 is mounted externally beneath the lower portion 2 of the vessel and has a drive shaft 8 rotatable about an axis inclined to the vertical as can be clearly seen from Figure 1. The free end of the shaft 8 enters the mixing vessel through a sealed bearing 9 in the lower portion of the vessel and an agitator 10 is fitted on to the free end of the shaft 8.

The agitator 10 is generally C-shaped, having two symmetrical arcuate arms 11, 12, and rotates about the said inclined axis so that the agitator 10 has a first arm disposed on one side of the axis and a second arm disposed on the other side of the axis.

The agitator 10 is also provided with scraper means 13 provided along the length of the agitator arms 11, 12 and positioned to scrape the lower portion 2 of the vessel over substantially the whole area thereof during each complete rotation of the agitator 10.

An emulsifier 14 extends downwardly from the lid 4 of the vessel so that its rotating head is adjacent a hub 15 of the agitator 10. The head is rotated by a shaft 16 driven by a second motor 17 mounted on the lid 4 of the vessel 1.

In operation of the prior art mixing apparatus, the material to be mixed is carried up the walls of the vessel 1 by the arms 11, 12 of the agitator 10 and then allowed to fall back, under gravity, into the vessel 1 as the arms conclude their upward path.

As has been mentioned the emulsifier 14 of this prior art arrangement is not conveniently positioned, and it tends to get in the way when filling and emptying the mixing vessel 1.

The present invention will now be described with reference to Figures 2 and 3 of the drawings, in which like members have been numbered as according to Figure 1.

The present invention comprises a mixing apparatus similar to that of Figure 1 but with certain modifications.

Referring to Figures 2 and 3 it is to be understood that in the present invention there is no overhead emulsifier as in the prior art, but instead the emulsifier is mounted on a shaft co-axial with the drive for the agitator, which is driven from below the mixing vessel. Thus the open mouth of the vessel is unobstructed.

Figure 2 shows a hollow drive shaft 20, for driving the agitator 10, extending into the mixing vessel 1. The shaft 20 is rotatable about an axis inclined to the vertical. The shaft enters the mixing vessel 1 through a sealed bearing 9 to prevent any of the contents of the vessel escaping therefrom.

The end of the hollow shaft 20 which extends into the mixing vessel 1 carries a substantially C-shaped agitator 10 for rotation therewith constituted by two, spaced, symmetrical co-planar arcuate arms 11, 12 which are intended to be releasably secured to the end of the drive shaft to enable the arms to be removed for cleaning purposes.

Scrapers (not shown) are spaced along the length of the agitator arms 11, 12 to which they are attached by bolts which allow an adjustable pivotable movement thereof. The outer edge of each scraper may be curved to conform to the spherical portion of the vesssel.

A motor 21 is mounted, on an appropriate supporting arrangement 22 in close proximity to the end of the hollow shaft 20 remote from the mixing vessel. The supporting arrangement 22 comprises a plurality of spaced posts which mount a motor supporting platform adjacent the underside of the mixing vessel 1. The motor 21 drives the hollow shaft 20 rotationally and thus also drives the C-shaped agitator 10 coupled thereto.

A stator 24 for an emulsifier, in the form of an annular body is mounted on the end of the hollow shaft 20 received within the mixing vessel 1, by means of the equi-angularly spaced mounting plates 25, only one of which is shown in Figure 2. The stator 24 is co-axial with the axis of the hollow shaft 20. The upper surface of the stator is provided with, in this example, two concentric rows of upstanding teeth 26 extending into the space defined within the mixing vessel 1.

A second drive shaft 27 is provided being co-axial with the first hollow shaft 20 and extending there through. The second drive shaft 27 is mounted for rotation within the hollow drive shaft 20 by two roller bearings 28 located adjacent the opposed ends of the hollow drive shaft 20. The end of the second drive shaft 27, remote from the mixing vessel 1, is coupled, through a suitable coupling 29, to a second motor 30 which drives it rotationally. The second motor 30 is mounted on a further motor support platform which is connected by support posts 31, to part of a housing 32 carried on the first motor support platform. A seal is provided at the end of the hollow shaft adjacent the coupling.

The other end of the second shaft 27 remote from the driving motor 30 and located within the mixing vessel 1 is provided with a rotor 33. The lower surface of the rotor is provided with concentric rows of annular grooves 34 which are provided to cooperate with the concentric annular teeth 26 provided on the stator 24. The arrangement of the rows of teeth 26 provided on the stator and grooves 34 provided on the rotor is such that when the rotor 23 is in position, the rows of teeth 26 on the stator are interposed with the annular grooves 34 provided on the rotor, whereby each row of teeth on the stator lies within an annular groove provided on the rotor.

A seal 35 is provided between the second shaft 27 and the end of the hollow shaft 20 within the mixing vessel 1 to prevent fluids from the mixing vessel 1 entering the hollow shaft 20.

In operation of the apparatus, a mixture to be processed is introduced, by means not shown, in to the mixing vessel 1. The hollow shaft 20, the stator 24 and C-shaped agitator 10 provided thereon are rotated at a selected speed in a first direction by the first motor 21. The second, coaxial shaft 27 and the rotor 33 provided at the end thereof are rotated in the opposite direction to the hollow shaft 20 by the second motor 30 coupled to the second shaft 27. The second shaft is driven at a relatively high speed compared with the speed of the hollow shaft 20.

There is a relative rotation between the stator 24 and the rotor 23 and the mixture being processed, when trapped between the teeth 26 provided on the stator and the corresponding grooves 34 provided in the rotor is subjected to a shear force which aids emulsification as the rotor 33 is rotated at a high rotational speed in relation to the stator.

The emulsifier that has been described, comprising a stator 24 and a rotor 33, is of the type that is described more fully in British Patent Specification No.

1388889 to which reference may be made. However, any convenient type of rotary emulsifier may be used in embodiments of the invention.

Both the C-shaped agitator 10 and stator 24 assembly and the emulsifier head can be run at variable speeds in order that the operator may have full control over the processing apparatus.

Claims

CLAIMS:

1. A rotary mixing apparatus comprising a vessel for containing materials to be processed, the vessel having a lower portion through which two co-axial shafts pass, the first being adapted to drive rotationally an agitator within the vessel, and the second shaft being adapted to drive rotationally an emulsifier rotor element for effecting emulsification of the material to be processed.

2. An apparatus according to claim 1, wherein the emulsifier rotor co-operates with an emulsifier stator carried on said agitator.

3. An apparatus according to claim 2, wherein the stator is provided with a plurality of concentric rows of upstanding teeth and the emulsifier rotor element is provided with a plurality of concentric rows of annular grooves such that, when the rotor is in position, the rows of teeth on the stator are interposed with the annular grooves provided on the emulsifier rotor element.

4. An apparatus according to claim 1, 2 or 3, wherein the first shaft is a hollow shaft and the second shaft passes therethrough.

5. An apparatus according to any one of the preceding claims, wherein a seal is provided within the mixing vessel between the second shaft and the end of the first shaft located within the vessel.

6. An apparatus according to any one of the preceding claims, wherein the apparatus further comprises two motors, the first adapted to drive the first shaft and the second adapted to drive the second shaft.

7. An apparatus according to claim 6, wherein the motor which drives the second shaft is adapted to drive the second shaft at a greater speed than the motor which drives the first shaft.

8. An apparatus according to any one of the preceding claims, wherein the lower portion of the vessel is substantially hemi-spherical and the agitator is partcircular, being mounted in the lower portion of the vessel so as to be rotatable in the vessel about an axis inclined to the vertical.

9. An apparatus according to claim 8, wherein the part-circular agitator is substantially C-shaped comprising a first arm and a second arm and the said inclined axis extends through the agitator in order that the first arm of the agitator is disposed on one side of the axis and the second arm is disposed on the other side of the axis.

10. A rotary mixing apparatus comprising a vessel for containing materials to be processed, the vessel having a substantially hemi-spherical lower portion through which two co-axial shafts pass at an inclination to the vertical, the first shaft being adapted to drive rotationally a part-circular agitator mounted within the lower portion of the vessel so that, upon rotation by the first shaft, the agitator passes over substantially the entire inner surface of the lower portion of the vessel, and the second shaft being adapted to drive rotationally an emulsifier rotor element for effecting emulsification of the material to be processed.

11. A method of mixing materials comprising the steps of introducing the materials into the vessel of a rotary mixing apparatus, the vessel having a lower portion through which two co-axial shafts pass, the first carrying an agitator and the second carrying an emulsifier rotor element within the vessel, the method comprising the further steps of rotationally driving said first and second shafts, thus driving the agitator and the emulsifier to mix and emulsify said materials.

12. Material whenever mixed by a method according to claim 10.

13. A rotary mixing apparatus substantially as hereinbefore described with reference to and as illustrated in Figures 2 and 3 of the accompanying drawings.

14. A method of mixing materials substantially as hereinbefore described.

15. Any novel feature or combination of features herein described.