AU663228B2 - Mixing device - Google Patents

Description

AUSTRALIA

Patents Act 663228 COMPLETE SPECIFICATION

(ORIGINAL)

Application Number: Lodged: Class Int. Class Complete Specification Lodged: Accepted: Published: Priority Related Art: 9 .9 03 0 0 0S** 9 0.96 0@ *o S 9* 60 9 0*S* S. O *5 C 0 Applicart(s) WYKNASH PTY LTD 42 Downing Street OAKLEIGH VIC. 3166 Address for Service is: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Complete Specification for the invention entitled: "MIXING DEVICE" Our Reference: 306181 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): 1 I MIXING DEVICE The present invention relates to a device for mixing fluids, in particular although not exclusively, gaseous fluids. The device is particularly applicable as a gas mixer for internal combustion engines, particularly where liquid petroleum gas (LPG) is used and it will be convenient to hereinafter describe the invention in relation to that exemplary application. It is to be appreciated however, that the invention is not limited to that application.

Due to rising prices of conventional engine fuels such as gasoline and diesel, there has been a tendency recently to convert the running of engines previously run on these fuels, to cheaper fuels, in particular LPG and ge 15 like fuels. As with most fuels, it is necessary to provide a mixing device through which the fuel may be "mixed with air prior to beingt 1 ce into the engine.

Such mixing devices are known for many different engines and in the case of gasoline run engines, this device is in the form of a carburettor, To effect a conversion to alternative fuel sources such as LPG, it is normal that the existing mixing device must be replaced or modified to suit the new fuel that is

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to be used. Where the engine is to be converted so as to run separately on both the original and the alternative fuel source, then it may be necessary to retain the original mixing device and include a further separate and distinct mixing device.

o* One mixing device particularly suited to the mixing *eU 30 of LPG or Compressed Natural Gas (CNG), is the subject of Australian 'atent No. 585853 to Amos Gas Mixers Limited.

The mixing device disclosed in this patent comprises an airflow passageway and a gas supply tube which enables gas flowing through the tube to mix with air flowing through the passageway. An important feature of this patent, is that part of the gas supply tube projects into the passageway and is of a substantially rectangular cross-section. While this type of mixing device may have advantages over previously known devices, applicant has 4 0 la found that this projection serves to obstruct air flow through the airflow passageway and therefore hinders the effective mixing of the air and fuel.

It is an object of the p esent invention to provide an improved fluid mixing device, which overcomes or at least alleviates some or all of the disadvantages associated with previously known mixing devices.

According to the present invention there is provided a mixing device for mixing fluids, said device including a first flow passage, a second foipw passage and a fluid distribution passage, said distribution passage including an opening in the form of an elongate slot which extends about at least a portion of the length of the distribution passage, wherein in use, fluid flowing through said flow passage enters said distribution passage for distribution through said elongate slot about at least a portion of the periphery of said second flow passage prior to entering said second flow passage and mixing with fluid flowing therethrough.

A device according to the invention is advantageous in that fluid and air may be "415 mixed without obstruction from tubing projecting into the air flow passage.

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In a preferred embodiment, the first flow passage extends into the distribution Sr passage such that fluid flowing through the first flow passage flows directly into the O distribution passage. The fluid may then flow about the full length of the distribution passage for distribution about the periphery of the second flow passage.

In a preferred embodiment, the distribution passage extends about the entire S. periphery of the second flow passage and the elongate opening extends the full length Sof the distribution passage.

The opening is preferably of such a dimension that fluid tends to flow about the full length of the distribution passage before it flows out through the opening, ie. the opening constricts to a certain degree the passage of fluid flow therethrough. This ensures that the fluid is full distributed within the distribution passage about the periphery of the second flow passage, to the extent to which the distribution passage extends about the second flow passage, before it exits the distribution passage.

Trhe opening is preferably 4-n 8 continuous elongate slot which ext ull length of the distribut'cithough other configurations may In order to assist in arriving at an understanding of the invention, a preferred embodiment is illustrated in the attached drawing. However, it should be understood that the following description is illustrative only and should not be taken in any way as a restriction of the generality of the invention as described above.

Figure 1 shows a plan view of one embodiment of the

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Figure 2 shows a cross-sectional view through II-II of Figure 1.

so Figure 3 shows a plan view of a further embodiment of the invention.

Figure 4 shows a cross-sectional view through IV-IV of Figure 3.

Referring to Figures 1 and 2, ,here is generally shown a mixing device 1 having an opening 2 to receive a first flow passage 3. The mixing device also includes a second flow passage 4. The first flow passage 3 includes .e :an inlet 5 and an outlet 6, while the second flow passage 4 includes an inlet 7 and an outlet 8.

The flow passage 3 is shown as a circular conduit 9 eeo which is attached in any suitable manner to the opening 30 2. While the first flow passage 3 is shown as a separate component for attaching to the opening 2, it is within the scope of the invention that the opening 2 forms the first flow passage 3. In this embodiment, the opening may be configured so as to enable a fluid supply line to be connected thereto and in this respect, the opening 2 may include an integral flange of a similar shape to that of the conduit 9. The conduit 9 or the opening 2 however, may take other forms and are not limited to that shown.

The conduit 9 is shown with a series of grooves 4 0 -3extending about its outer periphery and these grooves may be used to assist in attaching a source of fluid (not shown) to the inlet end 5 of the flow passage 3 ie. in cooperation with a clamping ring or other suitable component, although other methods of attaching a fluid source to the flow passage 3 are within the scope of the invention.

The flow passage 4 is shown as a centrally located circular opening through the mixing device 1 although other configurations of this passage may be appropriate.

The flow passage 4 is surrounded by a distribution passage 11. In this embodiment, distribution passage 11 is shown completely surrounding inlet 7, however, in a further preferred embodiment the distribution passage 11 need only 15 extend about a portion of the internal periphery of the o inlet 7. Additionally, the distribution passage 11 may be located at any point within the mixing device 1 although o. preferably between the inlet 7 and the outlet 8 as is appropriate.

The second flow passage 4 may also include means by which it maj be attached at both the inlet and the outlet to appropriate components of the fuel or air intake of an engine.

The distribution passage 11 may be formed into any appropriate configuration and in Figures 1 and 2 it e includes an L-shaped flange 12 and an L-shaped ring 13, defining a cross-sectionally square configuration. Other configurations may also be appropriate and may be formed by any suitable arrangement. The flange 12 is, in Figures 30 1 and 2, integrally cast with the housing 14, whereas ring 13 is a separate and distinct component which is press fitted into stepped portion 15. Other methods of attachment are clearly applicable.

The outlet 6 of the first flow passage 3 opens into the distribution passage 11 at any suitable location and may be oriented to suit the conditions to which it is to be fitted. This orientation may be determined by the components to which the mixing device 1 is to be connected, or may depend on the fuels used and the mixing 4

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An opening in the form of an elongate slot 16 is depicted in Figures 1 and 2 and this elongate slot 16 is located between the flange 12 and the ring 13. The slot 16 allows the gas in the distribution passage 11 to enter flow passage as shown by the arrows B. In this arrangement, the fluid flowing from the distribution passage is introduced into the second flow passage 4 at an angle approaching parallel to that of the flow of the fluid through the second flow passage 4. The angle of introduction may be varied by orienting the L-shaped flange 12 and the L-shaped ring 13 at an angle to that shown in Figure 2. Since the distribution passage 11 extends about the full circumference of the inlet 7, the 15 fluid entering the flow passage 4 via slot 16 is equally dispersed about the periphery of flow passage 4, thereby ensuring an advantageous mix ofA and air. A satisfactory mix of gas and air is however also achieved in an embodiment where the distribution passage 11 extends 20 about only a portion of the second flow passage 4, or where the slot 16 extends about only a portion of the distribution passage 11.

An alternative embodiment of a mixing device according to the invention is shown in Figures 3 and 4, 25 where like numerals are used for like parts shown in Figures 1 and 2. In this embodiment, the flange 12 is cast integrally with the housing 14, while the ring 13 is press fitted into a stepped portion 17. An elongate slot 18 is located between the flange 12 and the ring 13. The 30 mixing device 1 of this embodiment operates in a similar manner to that shown in Figures 1 and 2, although the flow of fluid from the distribution passage 11 to the second flow passage 4 differs, In this embodiment, air flows through the second flow passage 4 as indicated by the arrows A in a similar manner to that of Figure 2. Flow of fluid received from the first flow passage 3 through the distribution passage 11 however is indicated by the arrows C. In this embodiment, fluid tends to flow out of the distribution 140 5 00CR R R

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OD O passage 11 at right angles to the flow through the second flow passage. This creates a more turbulent mixing action compared with that of the arrangement shown in Figures 1 and 2 and may be more appropriate depending on the use to which the mixing device 1 is put. To more definitely control the angle at which fluid from the distribution passage 11 is introduced into the second flow passage 4, flange 13 may be made to project laterally further into air passage 4 than that shown, at whatever angle is desired, to thereby force the gas to exit distribution passage 11 at that angle and into the flow of fluid entering inlet 7.

It should be appreciated that in the two embodiments described in Figures 1 to 4, at least one of the flange 12 and the ring 13 is shown as being formed on the integral part of the housing 14. In another embodiment, both the flange 11 and the ring 12 may be integrally cast with housing 14, or may be formed separately and connected by any appropriate means thereto.

It will be appreciated in either embodiment, that the size of the slot is dependent on the proximal location of the ring 13 and the flange 12 and that the slot size may be varied to suit the air-fluid mixture required. Further, it is possible to provide a variable gap size by providing a threaded connection for the ring or the flange or both.

Conditions will determine the most appropriate arrangement to suit different engines S and their different uses and a person skilled in the relevant art will be able to adjust the mixing device accordingly.

As shown in Figures 1 and 3, the outer edge of housing 1 includes holes 19 for connecting the mixing device to any suitable engine component. The fitting may simply comprise nut and bolt attachment, utilising a gasket between the component parts. Any other suitable form of connection may also be used, including welding, threading, press o• fitting, etc. Further, both the inlets 5 and 7 and the outlets 6 and 8 respectively may include means to attach componentry as required. This may include flow pipes or tubes to lead the respective fluids to be Oo S S S mixed, to the respective inlets. The outlet of the second flow passage may also include means to attach it to an appropriate location on the engine (not shown).

It is envisaged that in the embodiments shown, the fuel will inducted, pumped or otherwise made to flow through the first flow passage 3 and that air will be made to flow through the second flow passage 4 for mixing with the fuel 4 ox i-ng- from the distribution passage 11, although it is within the scope of the present invention that the opposite arrangement is possible.

Fuel and air mixed in a mixing device according to the invention is mixed thoroughly and efficiently and is not obstructed by component parts located in the flow paths. The mixture thus obtained therefore contributes to 15 fuel efficiency and promotes smoother engine running.

Those skilled in the art will appreciate that there may be many variations and modifications of the configuration described herein which are within the scope of the present invention.

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Claims (14)

1. A mixing device for mixing fluids, said device including a first flow passage, a second flow passage and a fluid distribution passage, said distribution passage including an opening in the form of an elongate slot which extends abou tthe,'full length of the distribution passage, wherein in use, fluid flowing through said first flow passage enters said distribution passage for distribution through said elongate slot about the periphery of said second flow passage prior to entering said second flow passage and mixing with fluid flowing therethrough.

2. A mixing device according to claim 1, wherein said first flow passage extends into said distribution passage.

3. A mixing device according to claim 1 or claim 2 wherein said distribution passage extends about the full periphery of the second flow passage, for distribution of fluid about the full periphery of the second flow passage.

4. A mixing device according to any one of claims 1 to 3, wherein said mixing device includes a housing having an opening to receive the first flow passage. A mixing device according to claim 4 wherein said first flow passage is in the S form of a conduit.

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6. A mixing device according to claim 5 wherein said first flow passage is in the form of a conduit, which conduit is attached to said housing opening.

7. A mixing device according to any one of claims 4 to 6, wherein said housing includes a further opening which constitutes the second flow passage.

8. A mixing device according to any one of claims 4 to 7, wherein said housing S includes a channel and a flange located over the open end of said channel to thereby form the distribution passage, said flange being located so as to leave an opening in the distribution passage to enable fluid received from said first flow passage to pass OSSO Sinto said second flow passage.

9. A mixing device according to any one of claims 4 to 8, wherein said housing is cast and said flange is separately fitted to said casting.

A mixing device according to any one of claims 1 to 9, wherein in use, fuel is fed into said first flow passage and air is fed into said second flow passage, the fuel and air being mixed as said fuel exits said distribution passage.

11. A mixing device according to claim 10 wherein said fuel is a gaseous fuel, e.g. liquid petroleum gas or compressed natural gas.

12. A mixing device according to any one of claims 1 to 11, wherein said mixing device includes attachment means for attaching said mixing device to fluid supply lines and to an internal combustion engine.

13. A mixing device substantially as herein described with reference to any one of the embodiments thereof as illustrated in the accompanying drawings.

14. An engine having a mixture device according to any one of claims 1 to 13. DATED: 19 July 1995 BY PHILLIPS ORMONDE FITZPATRICK 4 6 Patent Attorneys per WYKNASH PTY LTD 0 S ABSTRACT A mixing device 1 for mixing fluids, said device including a first flow passage 3, a second flow passage 4 and a distribution passage 11, wherein in use, fluid flowing through said first flow passage 3 enters said distribution passage 11 for distribution about at least a portion of the periphery of said second flow passage 4 prior to entering said second flow passage 4 and mixing with fluid flowing therethrough. 00 0 S OSO a 0O S *0 OS Ike#& 0 10