GB1595294A - Mixing apparatus - Google Patents

Description

PATENT SPECIFICATION

( 11) 1 595294 Application No 45675/76 ( 22) Filed 3 Nov 1976

Complete Specification filed 12 Dec 1977

Complete Specification published 12 Aug 1981

INT CL 3 BO O F 5/12 7/181/ 5/06 Index at acceptance Bl C 18 A 115 B 1 C Inventor STANLEY ALBERT PLATTS ( 54) MIXING APPARATUS ( 71) We, UNISHEAR MIXERS LIMITED, a British Company formerly of Dial Trading Estate, Dial Lane, Andnam, Stowbridge, West Midlands, DY 8 4 YP, and now of Great Bridge Industrial Estate, Toll End Road, Great Bridge, Tipton, West Midlands, DY 4 OHR, do hereby declare this invention for which we pray that a Patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement:This invention relates to a multi-purpose mixing apparatus for mixing together materials such as solids and liquids for example, and has for an object to provide such an apparatus in which delivery of mixing materials therefrom is facilitated.

According to the invention, a mixing apparatus comprises a first bladed rotary impeller mounted for and drivable in rotation by drive means, means closely surrounding the first impeller and forming generally radial openings arranged in relation to the impeller blades such that material fed to the rotating impeller is urged by the impeller outwardly through said openings and subjected to a shearing action by cooperating edges of the blades and openings, a discharge chamber being arranged to receive sheared material passing through the openings and having restricted outlet means whereby material within the discharge chamber is subjected to an increase in pressure enabling the material to be discharged under pressure from an outlet of the discharge chamber.

In one convenient arrangement, a second bladed rotary impeller is provided and surrounded by a further means forming openings, said second impeller being arranged to urge material through the openings of said further means proir to action thereon by the first impeller.

Preferably, the main and second impellers are driven by and spaced along a common shaft connected to said drive means, the impellers being separated by a disc defining, in part, first and second mixing chambers each containing one of the impellers.

The invention will now be described, by way of example, with reference to the accompanying drawings in which:Figure 1 is a part-fragmentary perspective view of one form of mixing apparatus of the 55 invention; Figure 2 shows the impellers of Figure 1 in more detail but in another embodiment of mixing apparatus of the invention, and Figure 3 is a part fragmentary perspective 60 view of an alternative form of mixing apparatus of the invention.

Referring to Figure 1, the mixing apparatus shown therein is intended for use in the mixing of solids with liquid, as for 65 example in the manufacture of foods, paints and varnish The mixing apparatus comprises an outer container 1 having an inner partition 2 and a drain tap 3 As well as dividing the container into upper and lower 70 portions 4 and 5, the partition 2 serves to support a mixing mechanism which includes frame members 6 to which is fixed above the container 1 a driving means, conveniently in the form of an electric motor from which 75 depends a drive shaft 7 The drive shaft is supported at its lower end in a convenient form of bearing mounted in an annular supporting frame 6 A located on the under-side of the partition 2 80 Secured to the lower end portion of the drive shaft 7 is a pair of impellers 8, 9 mounted one above the other and each having three blades angularly spaced apart by 1200, the blades of the upper impeller being 85 angularly spaced with respect to the blades of the lower impeller by 600 The impellers are axially separated by a disc 10 (Figure 2) and the impellers and disc may conveniently be formed as a single casting with the blades 90 projecting from opposite sides of the disc.

Although very little detail of the impeller construction can be seen in Figure 1, it can be seen more clearly from Figure 2 in which the upper impeller blades are designated 95 8 A, the lower blades 9 A and the separating disc is designated 10 Although Figure 2 shows an alternative embodiment of mixer, the impeller therein may conveniently be the same as that in the Figure 1 arrange 100 C ( 21) cq ( 23) tn ( 44) 0 ( 51) tn ( 52) ( 72) ( 19 1 595 294 ment.

The upper impeller is surrounding by a stationary annular member 11 having a series of large openings 12 therein and defining with the disc 10 an upper mixing chamber 13 The lower impeller 9 is surrounded by a stationary annular member 14 having a large number of openings 15 which are smaller than the openings 12 The annular member 14 defines with the disc 10 a lower mixing chamber 16 surrounding the member 14 is a hollow casing 17 which defines with the member 14 a pumping chamber 18, from which extends a discharge pipe 19 leading to a three-way valve 20, one outlet 21 of which leads back into the container 1 for recirculation and the other outlet 22 of which leads to an external discharge location.

Also provided within the container 1 is a vortex control plate 23 which is slidable in a vertical direction on the frame members 6 from a position in which it is in abutting relationship with the upper surface of the annular supporting frame 6 A so as, in use, to control the vortex created by the upper impeller 8 Movement of the plate may be effected via an operating rod 24 by means of a suitable handle or lever (not shown).

Material to be mixed is supplied to the upper portion 4 of the chamber 1 and is allowed to feed into the upper mixing chamber 20 under the control of the vortex control plate 23 The outer edges of the blades 8 A of the upper impeller move in close proximity to the peripheral edges of the openings 12 and, as the impeller draws material, which may be a mixture of lumpy solids and a liquid, into the chamber 13 and expels it outwardly through the openings 12, a shearing action takes place between the aforesaid edges of the blades and openings which rapidly breaks down the solid limps and effects and efficient mixing thereof with the liquid.

Material passing outwardly through the openings 12 will arrive in the lower portion of the container and will be drawn into the lower mixing chamber 16 by the action of the lower impeller 9 A similar action to that described for the impeller 8 is provided by the impeller 9, shearing taking place between the blades 9 A and the edges of the openings 15 and a more finely divided and thoroughly mixed material is ejected outwardly through the openings 15 into the pumping chamber 18 The latter is sealed around the top and bottom edges of the member 14, except for the openings 15 and the discharge pipe 19 which forms, a restricted outlet means As a result, an increase in pressure will be created within the chamber 18, due to the forcing thereinto of material by the lower impeller 9 and this material will be forced along the pipe 19 to be discharged either via outlet 21 back into the container 1 for further mixing, or to an external discharge location via the outlet 22, depending upon the position of the threeway valve 20 70 The construction of Figure 2 is basically similar to that of Figure 1, the main difference being that the lower mixing chamber 16 acts also as the pumping chamber The upper and lower mixing chambers have a 75 common peripheral wall, the upper chamber wall having relatively large openings 12 and the lower chamber wall having smaller openings 15 The lower mixing chamber has the outlet pipe 19 and the size of the holes 80 is chosen in relation to the impeller speed to permit a sufficiently increased pressure to build up in the chamber 16 to provide the desired pumping action through the pipe 19.

The mixer of Figure 2 would normally be 85 used within a container which may conveniently be similar to that shown in Figure 1.

Many modifications and variations can be made to the apparatus described above It would, for example, be possible in any of the 90 embodiments described to provide means, such as a rotatable sleeve surrounding the outer wall of the pumping chamber, to adjust the size of the holes 15, making it possible for the feed pressure to the outlet 95 to be controlled The invention may also be applied to the mixing apparatus described in British Patent No 1341441.

Figure 3 shows the mixer of the invention incorporated in a closed unit which has a 100 body 31 having a flanged inlet pipe 32 and a pair of flanged outlet pipes 33 The body is provided with frame members 34 to support a motor as before and a shaft support 35 through which extends a drive shaft for the 105 mixer impellers The mixer mechanism itself is basically an inverted version of that shown in Figure 1, the chamber 13 being connected via a venturi 36 to the inlet pipe 32, the lower end of the venturi being sealed against 110 the adjacent end surface 37 of the body.

In use, the inlet 32 would be connected, for example, to a tank, from which material to be mixed is fed along the venturi 36 and into the chamber 13, from which it is dis 115 charged under the action of the impeller 8 through the holes 12 and into the interior of the body 31 The body will gradually fill with material until the level is high enough for this material to pass through holes 37 in 120 the upper end of the casing 17 and into the mixing chamber 16 Here the material is further mixed by the impeller 9 and expelled from the mixing chamber through the openings 15 in the annular member 14 and into 125 the pumping chamber 18 The pumping chamber communicates with the outlets 33 and ressure build-up in the pumping chamber causes liquid to be discharged therefrom through these outlets 130 3 1 595 294 3 The apparatus of Figure 3 may be used, as described, to mix liqiud fed from a tank and the mixed liquid can either be recirculated to the tank from the outlets 33 or conducted by suitable piping from the outlets to a desired location The apparatus of Figure 3 could alternatively be connected into a pipeline at the inlet 32 and in this case it would be desirable for only one outlet to be provided, from which the mixed liquid could reintroduced into the pipeline from the outled 33 downstream of the mixer.

Claims (14)

WHAT WE CLAIM IS:-

1 A mixing apparatus comprising a first bladed rotary impeller mounted for and drivable in rotation by drive means, means cloesly surrounding the first impeller and forming generally radial openings arranged in relation to the impeller blades such that material fed to the rotating impeller is urged by the impeller outwardly through said openings and subjected to S shearing action by co-operating edges of the blades and openings, a discharge chamber being arranged to receive sheared material passing through the openings and having restricted outlet means whereby material within the discharge chamber is subjected to an increase in pressure enabling the material to be discharged under pressure from an outlet of the discharge chamber.

2 A mixing apparatus according to Claim 1, wherein a second bladed rotary impeller is provided and surrounded by a further means forming openings, said second impeller being arranged to urge material through the openings of said further means prior to action thereon by the first impeller.

3 A mixing apparatus according to Claim 2, wherein the first and second impellers are driven by and spaced along a common shaft connected to the drive means.

4 A mixing apparatus according to Claim 2 or Claim 3 wherein the impellers are axially separated by a disc defining, in part, first and second mixing chambers, each containing one of the impellers.

A mixing apparatus according to any one of Claims 2 to 4, wherein blades of the first impeller are angularly spaced with respect to blades of the second impeller.

6 A mixing apparatus according to Claim 4, wherein the impellers and disc are formed in one pieces with the blades of the 55 respective impellers projecting from opposite sides of the disc.

7 A mixing apparatus according to any one of Claims 2 to 6, wherein the openings in said means surrounding the first impeller 60 are larger than those in the further means surrounding the second impeller.

8 A mixing apparatus according to any one of the preceding Claims wherein the outlet incorporates valve means for control 65 ling discharge therefrom.

9 A mixing apparatus according to any one of Claims 4 to 8, wherein an enclosure having an inlet for fluid to be mixed.

A mixing apparatus according to 70 Claim 9, wherein the enclosure is formed within a container for material to be mixed, the container being divided by a partition partially defining the enclosure, and the partition having an opening forming an inlet to 75 the mixing chamber containing the first impeller.

11 A mixing apparatus according to Claim 10, wherein passage of material through the opening in the partition is con 80 trolled by a vortex control plate adjustably mounted adjacent to said partition opening.

12 A mixing apparatus according to Claim 10, wherein the enclosure is formed by a casing encircling the mixing chambers 85 and having an inlet and an outlet, the inlet communication via a venturi tube with the mixing chamber containing the first impeller, which chamber discharges material mixed by the first impeller into the casing, 90 the mixing chamber containing the second impeller communicating with the casing to receive material therefrom which is discharged from the latter chamber through the outlet 95

13 A mixing apparatus according to Claim 12, wherein the chamber is generally cylindrical and has a plurality of outlets angularly spaced therearound.

14 A mixing apparatus substantially as 100 hereinbefore described with reference to Figure 1, Figure 1 as modified by Figure 2, or Figure 3 of the accompanying drawings.

MARKS & CLERK, Alpha Tower, ATV Centre, Birmingham Bl i TT.

Agents For the Applicants.

Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd, Berwick-upon-Tweed, 1981 Published at the Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.

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