US3894694A

US3894694A - Mixing devices

Info

Publication number: US3894694A
Application number: US377435A
Authority: US
Inventors: Nathan Rothman
Original assignee: SILVERSON MACHINES Ltd
Current assignee: SILVERSON MACHINES Ltd
Priority date: 1972-07-13
Filing date: 1973-07-09
Publication date: 1975-07-15
Anticipated expiration: 1992-07-15
Also published as: FR2192861A1; FR2192861B3; DE2335773A1; IT991165B; GB1443415A

Abstract

A mixing device comprising co-operating rotor and stator elements. The rotor element is made up of a plurality of blades mounted at one end of a shaft. The stator element has a generally cylindrical side wall formed with a series of small outlet apertures and at least one further outlet aperture whose area is substantially greater than the area of each small aperture.

Description

United States Patent Rothman July 15, 1975 MIXING DEVICES {56] References Cited [75] Inventor: Nathan Rothman, Chesham, ED ES ATENTS land 2,886,254 5/l959 Rohlinger et al. 24l/74 Assignee: Silverson Machines Limied, 3,380,669 4/1968 Hatton 241/46 R Ch h E 1 es am g and Primary Examiner-Roy Lake Filed: July 9, 1973 Assistant E.mminerDeWalden W. Jones [2]] App. NO: 377435 Attorney, Agent, or Firm-Browdy and Neimark [57] ABSTRACT [30] Foreign Application Priority Data A mixing device comprising co-operatmg rotor and July I972 Umted Kmgdom 32842/72 stator elements. The rotor element is made up of a plurality of blades mounted at one end of a shaft, The [52] US. Cl 241/4611; 241/83 Stator element has a generally cylindrical Side wall [5 l] "3" Bozc formed with a series of small outlet apertures and at [58] new of Search 24l/46 46014606 least one further outlet aperture whose area is sub- 24l/46.08, 46.1l. 46.15, 46. 17.728.839.813 stantially greater than the area of each small aperture.

5 Claims, 3 Drawing Figures MIXING DEVICES This invention relates to mixing devices.

According to the present invention a mixing device comprises co-operating rotor and stator elements of which the rotor element comprises a plurality of blades mounted at one end of an elongated shaft adapted at an opposed end thereof for coupling to an output shaft of a motor and the stator element comprises a generally cylindrical side wall formed with a series of outlet apertures and with at least one further outlet aperture of substantially greater area than the area of each of the apertures in the said series of apertures.

Suitably, a pair of the said further outlet apertures are provided. The said pair of outlet apertures are then preferably disposed at diametrically opposed locations on the cylindrical side wall of the stator element.

Preferably, the or each further outlet aperture area has an area which is between six and twenty times the area of each of the said series of apertures.

Preferably, the or each further outlet aperture is spaced from the axially outer ends of the side wall of the stator element.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a first device according to the invention;

FIG. 2 is a perspective view of a stator element in the device of FIG. 1; and

FIG. 3 is a perspective view of a stator element in a second device according to the invention.

The mixing device shown in FIGS. 1 and 2 of the drawings is particularly suitable for use in disintegrating and then mixing with a liquid granular material such as mustard seeds. The device is also suitable for use in mixing and disintegrating other material such as rubbers, resins or polymers in granular form.

In the present device mixing and disintegration of the above materials is effected by co-operating rotor and stator elements I and 3, respectively.

The rotor element 1 includes four blades 5 which are secured to one end of an elongated shaft 7 and extend radially outwardly from the shaft at equi-angularly spaced locations. Each blade 5 has a radially outer edge thereof parallel with the axis of the shaft 7. At its end remote from the blades 5 the rotor shaft 7 is connected to an output shaft of an electric motor 9 which is mounted on an upright stand II with the output shaft thereof extending vertically downwardly.

The stator element 3 includes a pair of annular end walls l3 and a cylindrical side wall which is clamped between the end walls 13 by a pair of axially extending bolts 17. Support means 19 of the type disclosed in our specification No. l,258,898 pendantly support the stator element 3 from the housing of the motor 9.

Referring to FIG. 2, the side wall 15 of the stator element 3 is formed with a series of small outlet apertures 21 which are arranged in twelve circumferentially extending. axially spaced rows, each aperture 21 being circumferentially displaced relative to the aperture of the or each adjacent row. Each of these smaller apertures 21 is circular in section.

Additionally, the side wall 15 of the stator element is formed with two outlet apertures 23 each of which has an area substantially greater than the area of each of the above-mentioned small apertures 21. These two larger outlet apertures 23 are disposed at diametrically opposed locations on the side wall 15 of the stator element 3. Each aperture 23 is circular in section and has an area approximately ten times the area of each of the smaller apertures 21.

The stator element 3 employed in the present device is changed to suit the material which is to be mixed and disintegrated. For mixing and disintegrating mustard seeds the stator element 3 selected is one wherein each of the series of small outlet apertures 21 has crosssectional area of one thousandth of a square inch, which is smaller than the initial cross-sectional area of the seeds. As mentioned above, each of two larger outlet apertures 23 has a cross-sectional area which is aproximately l0 times the area of a seed.

When assembled for use the rotor blades 5 are arranged within the stator element 3 and the rotor shaft 7 extends upwardly through the central aperture in the upper end wall 13 of the stator and through an apertured boss formed on an outer surface thereof, the end wall 13 and the boss serving to provide bearing surfaces for the lower end of the shaft 7. The internal diameter of the side wall 15 of the stator element 3 is only slightly greater than the diameter of the volume swept out by the rotor blades 5.

In use of the device the motor stand 1] is arranged alongside a mixing vessel with the motor shaft extending downwardly towards the vessel. Assuming that the device is used for mixing and homogenising mustard seeds with water the seeds are initially piled up at the bottom of the vessel. The rotor and stator elements I and 3, respectively, are immersed in the water above the seeds.

Upon energising the motor 9 water within the stator element 3 is rotated by the rotor blades 5 and is forced radially outwardly through the

outlet apertures

21 and 23 in the cylindrical side wall 15. Water and seeds are drawn upwardly from the lower part of the vessel and flow into the stator element 3 via the central aperture in the annular end wall 13 at the bottom of the element, replacing water expelled by the rotor element. Once inside the stator element 3 the seeds are also subjected to centrifugal forces which urge them radially outwardly towards the side wall 15 of the element.

With a stator element 3 having only the small outlet apertures 21, and no larger apertures 23, the element soon becomes blocked by the seeds or parts of seeds. Flow of seeds and water to and from the stator element 3 then ceases and seeds jammed between the rotor blades 7 and the stator element 3 eventually prevent the rotor 2 from rotating.

With a stator element 3 having only the two larger outlet apertures 23, or even more of such larger apertures, and no smaller apertures 21, it is found that there is a continuous flow of water and seeds to and from the element. However, there is little if any disintegration of the seeds.

With the present stator element 3 having both smaller apertures 21 and larger outlet apertures 23 it is found that a continuous flow of water and seeds to and from the stator element is maintained and that the seeds are rapidly disintegrated and homogenised to form a gel with the water.

It is believed that the larger outlet apertures 23 of the stator element 3 are responsible for maintaining the continuous flow of seeds and water through the element, thus preventing the jamming which takes place in their absence.

Seeds taking part in this flow are subjected to disintegration, and subsequently to mixing and homogenising by shearing forces exerted upon them by the relative movement between the rotor blades 7 and those parts of the stator element 3 formed with the small apertures 21.

Referring to FIG. 3 of the drawings, the stator ele' ment in a second mixing device according to the invention has a cylindrical side wall 31 which is also formed with a series of small outlet apertures 33 and two outlet apertures 35 of substantially greater area. The small apertures 33 of this second device are square in section. corresponding in size and shape to the outlet apertures in the stator element disclosed in our specification No. l,262,859. The two larger apertures 35 are disposed at diametrically opposed locations on the side wall 3] of the stator element and at respective axially outer ends of the wall. Each larger aperture 35 is generally rectangular in section and has an area approximately equal to twelve times the area of each small aperture 33.

I claim:

1. A mixing device comprising co-operating rotor and stator elements of which the rotor element comprises a plurality of blades mounted at one end of an elongated shaft adapted at an opposed end thereof for coupling to an output shaft of a motor and the stator element comprises a side wall which is formed with a series of outlet apertures and with one or two further outlet apertures of substantially greater area than the area of each of the apertures in the said series of apertures, the series of outlet apertures extending throughout a section of the side wall, the location of which section, in a direction axially of the device, corresponds to the axial location of the radially outer edges of the rotor blades, and the further outlet aperture or apertures also being disposed within the said section of the side wall.

2. A mixing device as claimed in claim 1, comprising a pair of the said further outlet apertures.

3. A mixing device as claimed in claim 2, wherein the said pair of further outlet apertures are disposed at diametrically opposed locations on wall side wal of the stator element.

4. A mixing device as claimed in claim 1, wherein the or each further outlet aperture has an area which is between six and twenty times the area of each of the said series of apertures.

5. A mixing device as claimed in claim 1, wherein the or each further outlet aperture is spaced from axially outer ends of the side wall of the stator element.