GB2269762A

GB2269762A - Flow mixers

Info

Publication number: GB2269762A
Application number: GB9317274A
Authority: GB
Inventors: Roger Melhuish
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-08-22
Filing date: 1993-08-19
Publication date: 1994-02-23
Anticipated expiration: 2013-08-19
Also published as: GB2269762B; GB9317274D0; GB9217933D0

Abstract

A mixing device 5 comprises a substantially hollow disc shaped body 10 having a plurality of first perforated inlet ports 25 on a first surface 10 thereof, at least one second inlet port (40) on an edge 35 thereof, and a plurality of first perforated outlet ports 30 on a second surface 20 thereof. A tubular member 45 having a perforated (50) side wall extends between each first inlet port and corresponding first outlet port 25, 30. The mixing device 5 may be suitably adapted for any particular application, such as: the mixing of air and petrol in a combustion engine or induction tract (Fig 8, not shown); the mixing of anaesthetic gases; the mixing of concrete; inhalers (Figs 6, 7, not shown); or blood oxygenation. <IMAGE>

Description

Mixing Device and Related Method Background of the Invention This invention relates to a device for, and method of, mixing two or more materials, each of the materials being in any phase whether gas, vapour, liquid, or particulate solid.

A problem exists in mixing two or more materials to provide a homogeneous mixture. This is particularly so where the materials flow together to form a laminar flow.

If the materials are not adequately mixed then the laminar flow will be disrupted and non-uniform - resulting in a variety of problems/disadvantages dependent upon the materials mixed, and the purpose to which the mixture is to be put. For example, materials to be mixed may be wasted. Further, the mixture may not act in a predictable fashion.

Objects of the Invention It is an object of the present invention to obviate or mitigate the aforementioned problems/disadvantages.

It is a further object, of at least some embodiments of the present invention, that where there may be a requirement for different concentrations in different parts of a flowing mixture to meet such a requirement.

Summary of the Invention According to a first aspect of the present invention there is provided a mixing device comprising a substantially hollow body having a plurality of first inlet ports on a first surface thereof, at least one second inlet port, and a plurality of first outlet ports on a second surface thereof.

Preferably the hollow body is of a disc shape.

Herein, "disc" means any substantially planar body of any suitable shape, eg. circular, elliptical, triangular, rectangular, square, hexagonal, etc.

Preferably also, the plurality of first inlet ports are on a first planar surface of the disc, the at least one second inlet port is on a side edge of the disc, and the plurality of first outlet ports are on a second planar surface of the disc which faces and is spaced from the first planar surface.

More than one second inlet port may be provided on the side edge of the disc, the second inlet ports being spaced around the side edge.

The plurality of first inlet ports and first outlet ports are preferably equal in number and substantially face one another.

Each of a plurality of tubular members is located between each first inlet port and corresponding first outlet port, a first end of each tubular member being in sealed contact with a perimeter of the respective first outlet port, a second end of each tubular member being in sealed contact with a perimeter of the respective first outlet port, each of the tubular members having one or more perforations in a side wall thereof.

Preferably, the first and second ends of each tubular member are in integral contact with the perimeters of the respective first inlet and first outlet ports.

The tubular members and corresponding first inlet and first outlet ports may be rectangular, stellate, circular, cruciform, diamond or elliptical in shape or cross-section or any other suitable shape and in any suitable combination thereof.

The mixing device may be suitably adapted for any particular application, such as: the mixing of air and petrol in, for example, a combustion engine or induction tract; the mixing of anaesthetic gases, for example, air/oxygen and an anaesthetic agent; or the mixing of gravel and sand and water and cement to form concrete.

The device may, therefore, be made of a material suitable for any particular application. For example, in the case of mixing air and petrol, the device may be made of a ceramic material, alloy, composite or pure metal or plastic, or a substrate with other material superadded eg.

by spraying, plating etc.

According to a second aspect of the present invention there is provided a method of mixing at least two materials comprising passing a first material into a substantially hollow body via a plurality of first perforated inlet ports on a surface of the body, passing at least one second material into the hollow body via each of at least one second inlet port(s), and passing a mixture of the first material and the at least one second material out of the hollow body via a plurality of first perforated outlet ports on a surface of the body.

Brief Description of the Drawings Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, which are: Fig 1. a planar view of a first embodiment of a mixing device according to the present invention; Fig 2. a side view of the mixing device of Fig 1 to a reduced scale; Fig 3. a partial cross-sectional side view of the mixing device of Fig 1 to an enlarged scale; Fig 4. a schematic side view of the mixing device of Fig 1; Figs 5(a) (b) (c) cross-sectional side views of various tubular members for use in the mixing device of Fig 1; Fig 6. a schematic side view of a second embodiment of a mixing device according to the present invention within an inhaler; Fig 7. a front view of the mixing device of Fig 5;; Fig 8. a schematic side view of a third embodiment of a mixing device according to the present invention within a cylinder of a combustion engine.

Specific Description Referring to Figs 1 to 4, there is provided a mixing device, generally designated 5, comprising a disc shaped substantially hollow body 10 having first and second (in this case upper and lower) spaced surfaces 15, 20.

On the first surface 15 there are provided a plurality of first perforated inlet ports 25, while on the second surface 20 there are provided a plurality of first perforated outlet ports 30.

The outer perimeters of the first and second surfaces 15, 20 are joined via an edge 35 having at least one second inlet port 40 located thereon.

As can best be seen from Fig 3 the plurality of first inlet ports 25 and the plurality of first outlet ports 30 are, in this embodiment, equal in number, respective inlet and outlet ports 25, 30 substantially facing one another across the space between the surfaces 15, 20.

Further, the perimeter of each first inlet port 25 is in integral contact with a first end of a respective tubular member 45, a second end of each tubular member 45 being in integral contact with the perimeter of the corresponding first outlet port 30.

Each of the tubular members 45 has one or more further perforated ports 50 in a side wall thereof.

In use, a first through-flow material (not shown) is passed into the first inlet ports 25, while a second inflow material (not shown) is passed into the second inlet port 40.

The through-flow material passes from the first inlet ports 25 into the tubular members 45, while the second inflow material passes through the space between the first and second surfaces 15, 20 and into each of the tubular members 45 via the further perforated ports 50.

The through-flow and in-flow materials therefore mix within each of the tubular members 45, the mixture (not shown) passing out of each of the tubular members 45 via the plurality of first outlet ports 30.

In this way a "laminar" flow of the mixture of the through-flow and in-flow material is formed at the outlet ports 30, for subsequent use.

Fig 4 schematically shows the operation of the mixing device 5. Herein the inlet ports 25 are represented by A, B, C, D N, and the outlet ports 30 are represented by Al, Bi, Cl, Dl Ni.

Flow of through-flow material from A - > Al, B - > B1, C - > C1, D - > D1, ..., N - > N1 through the mixing device 5 is substantially uniform and laminar. In-flow material mixing with the through-flow material is evenly mixed with the through-flow material throughout the overall surface of the mixing device 5. Therefore, if "c" is the concentration of in-flow material then: cAl = cBl = cCl = cDl = .... = cNl where: N is the total number of first inlet ports 25 and also first outlet ports 30.

The ratio of the through-flow material to the in-flow material, whether by weight/weight, weight/volume or volume/volume or otherwise, can be precisely achieved by use of the mixing device hereinbefore described.

The mixing device 5 may be used to mix two or more gases or vapours, two or more liquids, or two or more particulate solids, or a combination of any of such.

Depending upon the application to which the mixing device 5 is put the following factors are all crucial and variable: the shape, size and number of first and second inlet ports 25, 40, and further ports 50 and first outlet ports 30, and also the proportion of the first and second surfaces 15, 20 which are perforated.

Other features which are also crucial and variable are: the overall shape and dimensions of the mixing device 5 and the material from which the mixing device 5 is made. For example, the mixing device 5 may be circular, elliptical, square or diamond shaped in cross section, and the overall shape of the mixing device 5 may be flat, conical, domed or stepped, for example.

Referring to Fig 5, it may be envisaged that the tubular members 45 may be cylindrical in shape or have concave or convex side walls.

If the tubular members 45 are cylindrical there is provided the advantage of not materially changing the flow of through-flow substance or material, eg air or the speed of mixing between first inlet and outlet ports 25, 30. If the side walls of the tubular members 45 are concave as in Fig 5(b), this would speed the flow of material, eg. air, from inlet 25 to outlet 30 by causing a venturi effect.

This would increase the speed of mixing within such tubular members 45. Conversely if the side walls are convex, this would slow the flow of material/substance from inlet 25 to outlet 30. Plainly the configuration of the tubular members 45 whether they be as in Figs 5 (a), (bi, (c) or of any other configuration is application specific.

Uses of the Mixing Device of the Present Invention Medical Uses The mixing device 5 according to the present invention has many and varied applications. For example the mixing device 5 may be adapted to be used in the mixing of anaesthetic gases, where gas (for example, air or oxygen) is mixed with an anaesthetic agent, Aa. If the mixing device 5 according to the present invention is used, a homogeneous mixture of gas and anaesthetic agent in laminar flow is provided . The concentration of the homogeneous mixture can be precisely controlled thereby minimising waste and ensuring the patient receives the correct effective dose.

Note that if two or more anaesthetic agents need to be used then sequential mixing devices 5 according to the present invention may be provided, each of the anaesthetic agents being introduced as the in-flow material into sequential mixing devices 5.

Additional medical applications for the device 5 could include: aeration or oxygenation of blood, eg in heart by-pass equipment; or incorporation into the design of inhalers as used by asthmatics so that the drug(s) can be uniformly mixed with inhaled air so avoiding waste.

Referring to Figs 5 and 6, in use an inhaler, 100' comprising a canister holder 105' and pressurised aerosol canister 110', the drug enters the mixing device 5' from the canister 110' via a connector 115' as the in-flow component and enters the space through which the air is flowing (the air here being the through-flow component) via third ports 50' of appropriate size, shape and number set in side walls of radially extending in-flow tubes 120' such that the drug enters the insterstices, ie air-spaces, around these tubes via 120' the appropriate ports 50'.

As can be seen from Fig 5 and 6, the tubes 120' are connected by an edge 35'. The size shape and number of the appropriate ports 50' is determined by: a) the type of drug in the canister and its physical properties, eg.

does it contain particulates (like sodium cromoglycate or liquid droplets as in, eg salbutamol); and b) the required concentration of drug to be inhaled by the patient.

Considerations a) and b) may also determine whether the in-flow tubes 120' in the device 5' are configured radially (as in Figs 5 and 6) or spirally, in rectangles, circularly, or whatever is most appropriate. Plainly such configurations do not only apply in drug delivery systems.

In all other applications of the device the configuration is determined by the properties of the materials to be mixed and the desired ratio or concentration of their mixing.

It should be noted that in this application (drug mixing with air), the second inlet tube 40' enters the mixing device at the centre of the device 5'. Such a configuration would not be solely limited to this particular application.

It has been found that, using inhalers, a bolus of aerosol or drug often hits the mucus membranes at the back of the throat. This has two effects: 1) especially with cromoglycates this irritation of the mucus membranes sets up an instantaneous reflex cough which expels the drug via the mouth, thereby achieving absolutely the reverse of the desired effect and, therefore, needing more doses to counteract this elimination; 2) the impact of the drug on the mucus membranes means an unknown amount of drug is trapped on the mucus carpet and so becomes non-available for inhalation into the lungs.

Both 1) and 2) result in waste and therapeutic inefficiency. This waste can be obviated or mitigated by using a mixing device 5 according to the present invention.

Automotive Uses Another application of the present invention is in an internal combustion engine. A mixing device 5" may be provided in an induction tract or at or near the top of a combustion chamber 55", above the top dead centre (TDC) level of a piston 56", as shown in Fig 8. Air is introduced into the combustion chamber 55" via an inlet valve 60" as the through-flow material for the device 5", and petrol is introduced into the mixing device 5" via second inlet port 40" as the in-flow material. A laminar flow of petrol/air mixture is thereby provided within the chamber 55all, exhaust gases being removed via an exhaust valve 65"-.

Building Industry Uses Yet another example of an application of the present invention is in mixing of concrete. In such, gravel may be introduced into a first mixing device 5 as the throughflow material and sand as the in-flow material. The gravel and sand mixture is then used as the through-flow for a second device 5 in which cement is the in-flow material. The total mixture then passes through a third device 5 as the through-flow material, water being the inflow material at this stage, the end product of this sequence of devices 5 being concrete.

The embodiments of the invention described hereinbefore are given by way of example only, and are not meant to limit the scope of the invention in any way.

Particularly, it should be understood that the various applications of the present invention hereinbefore disclosed is in no way meant to be exhaustive, and that the invention may also find use in other situations.

Further it should be understood that in the embodiment hereinbefore disclosed each of the plurality of first perforated inlet ports 25 are substantially equal in size. Likewise the plurality of first outlet ports 30 are substantially equal in size. These embodiments will, therefore, provide a substantially uniform laminar flow, in use. However, it will be appreciated that the sizes of the first inlet and first outlets may be designed so as to provide a taylored flow having different concentrations across the cross-section thereof.

It should finally be appreciated that more than one second inlet port 40 may be provided, so that each inlet port 40 may be communicable with a distinct number of the first inlet ports 25, by means of baffles or the like provided in the body 10. For example, a first second inlet port 40 may communicate with first inlet ports 25 around the peripheral edge of the body 10, while a second second inlet port 40 communicates with the remaining first inlet ports 25. In this way a cylindrical column of a first mixture enclosed within a tubular column of a second mixture may be produced.

Claims

1. A mixing device comprising a substantially hollow body having a plurality of first inlet ports on a first surface thereof, at least one second inlet port, and a plurality of first outlet ports on a second surface thereof.

2. A mixing device as claimed in claim 1, wherein the hollow body is disc shaped.

3. A mixing device as claimed in claim 2, wherein the plurality of first inlet ports are on a first planar surface of the disc, the at least one second inlet port is on a side edge of the disc, and the plurality of first outlet ports are on a second planar surface of the disc which faces and is spaced from the first planar surface.

4. A mixing device as claimed in claim 3, wherein more than one second inlet port is provided on the side edge of the disc, the second inlet ports being suitably spaced around the side edge.

5. A mixing device as claimed in any of claims 3 or 4, wherein the plurality of first inlet ports and first outlet ports are equal in number and substantially face one another.

6. A mixing device as claimed in claim 5, wherein each of a plurality of tubular members is located between each first inlet port and corresponding first outlet port, a first end of each tubular member being in sealed contact with a perimeter of the respective first outlet port, a second end of each tubular member being in sealed contact with a perimeter of the respective first outlet port, each of the tubular members having one or more perforations in a side wall thereof.

7. A mixing device as claimed in claim 6, wherein the first and second ends of each tubular member are in integral contact with the perimeters of the respective first inlet and first outlet ports.

8. A mixing device as claimed in claims 6 or 7, wherein at least some of the tubular members and respective first inlet and first outlet ports are rectangular, stellate, circular, cruciform, diamond or elliptical or cross-section or any other suitable shape and in any suitable combination thereof.

9. A mixing device as claimed in claims 6, 7 or 8, wherein at least some of the tubular members have either concave or convex side walls.

10. A mixing device as claimed in claim 4 or any of claims 5 to 9 when dependant upon claim 4, wherein each second inlet port is communicable with distinct first inlet ports by means of baffles or the like provided in the body.

11. A mixing device as claimed in any preceding claim, wherein the device is made of a ceramic material, alloy, composite or pure metal or plastic, or a substrate with other material superadded eg. by spraying or plating.

12. A mixing device as claimed in any preceding claim adapted for use in the field of medicine, eg, in the mixing of anaesthetic gases, aeration or oxygenation of blood, or in inhalers.

13. A mixing device as claimed in any preceding claim adapted for use in the field of the automotive industry, eg, in the mixing of air and petrol in a combustion engine or induction tract.

14. A mixing device as claimed in any preceding claim adapted for use in the field of the building industry, eg, in the mixing of cement.

15. A method of mixing at least two materials comprising passing a first material into a substantially hollow body via a plurality of first perforated inlet ports on a surface of the body, passing at least one second material into the hollow body via each of at least one second inlet port(s), and passing a mixture of the first material and the at least one second material out of the hollow body via a plurality of first perforated outlet ports on a surface of the body.