New Zealand No 332193 International No PCT/NZ97/00024
TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION
Priority dates 01 03 1996,
Complete Specification Filed 03 03 1997
Classification (6) F01 N1/12.10
Publication date 28 October 1999
Journal No 1445
NEW ZEALAND PATENTS ACT 1953
COMPLETE SPECIFICATION
Title of Invention
Emission control and/or silencer and/or separator and/or mixing apparatus
Name, address and nationality of applicant(s) as in international application form
KITE, ROBERT ERNEST JAMES, 16 Goldsmith Terrace, Napier, New Zealand, KITE, MURRAY JAMES, 69 Avondale Road, Napier, New Zealand, Kite, Murray James and Kite, Robert Ernest James
EMISSION CONTROL AND/OR SILENCER AND/OR SEPARATOR AND/OR MIXING APPARATUS
BACKGROUND
This invention relates to a silencer or separator or mixing apparatus and/or a emission control system and, in particular, although not necessarily solely, a silencer to act as a muffler on vehicle internal combustion engines or stationary engines Other embodiments may be provided for alternative uses such as mixing fluids, separating oil from water or otherwise
Conventional muffler apparatus comprises relatively large mufflers haviag a series of baffle plates to increase back pressure in tho exhaust system and to reduce noise Many mufflers incorporate perforated tubes wrthin the muffler to allow for some dispersion of the exhaust gases into an outer housing, however, the form and efficiency of such mufflers have been restricted In particular, mufflers are generally arranged in a straight section of exhaust pipe and do not easily facilitate difficult fitment arrangements where alternatively shaped mufflers may be more desirable Such conventional mufflers are generally bulky requiring special accommodation in the design of the underneath profile of a vehicle
Obiect of the Invention
It is an object of the present invention to provide a silencer or separator and/ or emission control system which will overcome some of the disadvantages of the prior art or at least provide the public with a useful choice
Printed trom Mimood
o 7 / r\ n n " '
* *«»~ j - i i
RECEIVED 2 0 MV/ 1933
Summary of the Invention
Accordingly, in a first aspect, the invention may broadly be said to consist in a silencer or separator or mixing apparatus and/or emission control system including an outer housing,
an inner conduit within said housing,
a material in a region between said housing and said conduit, and wherein at least a portion of said inner conduit includes perforated helically spiralled walled tube providing helically spiralled projections along its inner wall and to cause a fluid flowing through said inner conduit to adopt a spiral flow causing an outwardly directed force on said fluid and to create a back pressure and to cause at least a portion of the fluid to pass through said perforations to contact at least a portion of said material before re-entering said inner conduit and to thereby achieve a required silencing, mixing and/or emission controlled operation
Accordingly, in a second aspect, the invention may broadly be said to consist in a method of silencing or separating or mixing and/or emission control including the steps of providing an outer housing,
providing an inner conduit from perforated tube,
providing said perforated tube with helically spiralled projections along its inner wall so that a fluid flowing through said inner conduit will adopt a spiral flow causing an outwardly directed force on said fluid and creating a back pressure,
CORRECTED 'EX-OFFICIO 'PPA/AU
- 2A -
RECEIVED 2 0 :1 AY 1933
positioning said helically spiralled tube within said outer housing with said material positioned between said inner conduit and said outer housing, so that at least a portion of said fluid will pass through said perforated tube to contact at least a portion of said material before re-entering said inner conduit and to thereby achieve a required silencing, mixing and/or emission control
Brief Description of the drawings
Preferred embodiments of the invention will now be described with reference to the following drawings in which
CORRECTED -^(-OFFICIO °EA/AU
WO 97/32117 PCT/NZ97/00024
Figure 1a is a cross-sectional front elevation of a conventional silencer apparatus,
Figure 1b is an end elevation of the apparatus of figure 1,
Figure 2a is a cross-sectional elevation through one embodiment of the present invention,
Figure 2b is an end elevation of the apparatus of figure 2a,
Figure 3 is a cross-sectional elevation of a further embodiment of the invention,
Figure 4 is a cross-sectional elevation through a yet further embodiment of the invention, and
Figure 5 is a cross-sectional elevation through a yet further embodiment of the apparatus
Details description of preferred embodiments
Referring to the drawings, one type of conventional muffler or silencer 1 is shown It can be seen that the silencer provides an outer housing 2 and an inner conduit 3 extending through the outer housing 2 Intermediate of the outer housing 2 and inner conduit 3 is a porous material 4 which may comprise a variety of materials
Printed from Mirr.oc i
rCT/NZ97/00024
As shown in figure 1 a, the inner conduit 3 is provided with perforations so that there is some opportunity for the exhaust gases passing through the inner conduit 3 to diffuse throughout the porous material 4 before re-entering the inner conduit 3 and exiting out the outlet end 5
However, in such apparatus, there is a tendency for a large portion of the emissions travelling through the inner conduit 3 to stream through the uninterrupted central axial portion of the inner conduit 3 The confinement of the outer housing 2 combined with the porous material and pressures built up from previous exhaust passage through the muffler tends to increase this effect with exhaust gases passing through the inner conduit 3 having difficulty in passing through perforations 6 to the porous material 4 A straight line flow may be achieved through the inner conduit 3 over a substantial portion of the cross-sectional area of the inner conduit
3
Referring now to figures 2a and 2b, an embodiment of the invention is provided in the form of a silencer 1, again being provided with an outer housing 2 and inner conduit 3, perforations 6 in the inner conduit 3 and a porous material 4 intermediate of the inner conduit 3 and the outer housing 2 However, in this invention, the inner conduit 3 is provided with a helical spiral in the wall of the conduit 3 as shown by the ridges 7 in the wall of the conduit 3 This helical spiral provided in the inner conduit may alter the flow characteristics of the emissions passing through the inner conduit 3 such that a turbulent flow rather than a straight line flow is created in the exhaust emissions passing through the silencer
This turbulent flow may lead to an increase in the tendency of the exhaust gases to pass through the perforation 6 and, therefore, through the porous material
4
Printed from Mimosa
In this particular embodiment, the inner conduit 3 and outer housing 2 are provided as substantially coaxial cylindrical tubes It has been found that a silencer can be provided with substantially reduced cross-sectional area of the outer housing 2 with no substantial detriment and performance compared with the conventional silencer as shown in figures 1a and lb
A further embodiment of the invention is shown in figure 3 In this embodiment, the silencer 1 is shown as an extended section of the exhaust and is provided as a curved apparatus It has been found that apparatus in accordance with the invention can be relatively easily manipulated to accommodate bends in the exhaust system Therefore, there is no longer a restriction on the fitment of a silencer to a specific region on the vehicle which will accommodate the normal straight line muffler to be fitted This may be particularly important in silencers or mufflers fitted to vehicles where it may be desirable to provide a muffler or silencer extending from the exhaust manifold or thereabouts with limited room for a conventional straight line silencer
In a further preferred embodiment, an exhaust system as shown in figure 3 may allow attachment of the inlet end 8 to or adjacent the exhaust manifold This may allow considerable heat to be generated in the silencer particularly that portion most adjacent the inlet end 8 In such an embodiment, the porous material 4 may contain a catalytic material such as a porous platinum wool or other catalytic metallic wool The heat generated in the silencer due to the proximity to the exhaust manifold may provide sufficient temperatures for the efficient operation of the catalytic material and allow the porous material 4 to not only dampen noise in accordance with a conventional silencer but also provide some improvements in the emissions Such catalytic material may decrease the level of pollutants in the
Printed trorri Mimosa
emissions from the exhaust system such as carbon monoxide.
A further embodiment of the invention is shown in figure 4 In this instance, the silencer 1 is provided having an inner conduit 3 again in the form of a helically spiralled perforated tube, an outer housing 2 and a porous material 4 as with previous embodiments However, end plates 9 and 10 are provided in this embodiment so that the apparatus as shown in figure 4 may operate as a replaceable cartridge within an exhaust system, preferably with an outer housing to contain the cartridge
This may allow ease of replacement
Figure 5 shows a yet further embodiment which may be particularly provided for emission control In this instance, a large outer housing 2 in the form of a container is provided with the inner conduit 3 forming a suitable path throughout the container 2 to allow the inner conduit 3 to be surrounded by the fibrous material 4 Again, the fibrous material may be made from a variety of materials including metallic wool materials and, preferred, containing a catalytic material
To manufacture at least a preferred form of the apparatus, a straight cylindrical perforated tube may be formed to provide the helical spiral in the wall of the tube The preferred form of manufacture of such a helical spiral is described in international patent application No PCT/NZ93/00087
The matenals of manufacture may be any suitable materials and preferred embodiments at present have utilised steel with the outer housing 2 and the inner conduit 3 with welded connections as required adjacent an inlet end 8 and an outlet
Print"ed 1 rorn Mimosa
end 5 such as welded connections 11 and 12 The section of conduit 3 leading into and out of the silencer 1 may be continuous with the inner conduit 3 and the outer housing 2 welded at connections 11 and 12 to the inner conduit 3
The materials used may well depend on the final use to which it is put When used as mixer, depending on the fluids being mixed, plastic materials may be preferred Ceramics may be used, particularly in filtering apparatus Other materials may also be useful
The method of forming the invention and the reduced size of the resultant silencer may allow manufacture from more expensive materials such as stainless steel to inhibit corrosion
The invention may also be used as a separator to separate fluids such as oil and water or other fluids Again, the oil and water mixture may be put through the inlet into the apparatus and the helically nature of the central conduit should encourage the fluid through the material contained between the inner conduit and outer housing This material may be selected to filter oil from water or perform other filtration or separation requirements
In another embodiment, the apparatus could be used for the mixing of fluids with a second fluid being a liquid or gas being introduced into the apparatus such as into the material between the inner and outer conduits adjacent the inlet under a line on the passage of the inlet fluid through this material between the two conduits to provide a comprehensive mixing of the fluids Otherwise, the two fluids could merely be introduced simultaneously downstream of the inlet and the apparatus may provide the mixing effect the between the fluids as the fluids are both caused
Printed trorn Himora
to interact in passage through the material sandwiched between the two conduits
Thus it can be seen that the invention provides a silencar and/or an emission control system which may provide some advantages over the prior art by providing a helically spiralled inner conduit to alter the flow conditions through the inner conduit 3 to a more turbulent flow Bnd increase the likelihood of the emissions to pass through the preparation 6 in the wall of the inner conduit 3
Where in the foregoing description reference has been made to integers or components having known equivalents then such equivalents are herein incorporated as if individually set forth
Although this invention has been described by way of example it ii> to he appreciated that improvements and/or modifications may be made thereto without departing from the scope of the present invention as defined in the appended claims
Printed from Mimosa
-2 7 / 0 0 0 2 '
- 9 - RECEIVED 2 n f ] AY 12D2