NZ229544A

NZ229544A - Exhaust silencers formed from perforated cylindrical rings

Info

Publication number: NZ229544A
Application number: NZ229544A
Authority: NZ
Inventors: Sven-Olof Malmsten
Original assignee: Dorchester Enterprises Ltd
Priority date: 1988-06-15
Filing date: 1989-06-14
Publication date: 1992-03-26
Also published as: IL90614A0; SE461418B; HU893883D0; EP0426696A1; SE8802235L; DD287079A5; ES2015712A6; OA09585A; PT90858A; JPH03505113A; FI906134A0; GR890100381A; HUT57874A; SE8802235D0; WO1989012732A1; CN1051410A; ZA894506B; DK297990D0; DK297990A; BR8907489A

Description

MtK 229544 Priority Dat*4»): ;Compute Specification Flloci: .....\bt»..Y£.:...<P....j. Close: (5)... .17.. S. 1 .tv).7T7 ;.'.W2. ./.'. b. / • ..IT. . J. U. W J.. ./.I Lc ;'■■rsmm ;Publication Date: ;P.O. Journal,-No: y. ...A.^.Ur. - ;Patents Form No. 5 ^ ; ;o'-\ ;•<N\ vl ;NEW ZEALAND ^ 4 JU/V/9g9^7 ;y ;PATENTS ACT 1953 " ? v ;COMPLETE SPECIFICATION ;AN EXHAUST SILENCER ANP A METHOD OF MAN'UFACTUR ING IT ;"S^/WE , DORCHESTER ENTERPRISES LTD, a company organised and existing under the laws of the British Virgin ;Islands of Skc)ton Building, Main Street, Road Town, ;Tortola, British Virgin Islands, ;hereby declare the invention, for which £/Ve pray that a patent may be granted to r^/us, and the method by which it is to be performed, to be particularly described in and by the following statement: ;- 1 - ;(followed by Page la) ;22 9 5 4 ;1 a ;The invention relates to an exhaust silencer of the type comprising an inner pipe, permeable to gas in radial direction, an outer casing and possibly a noise-suppressing material arranged between the pipe and the outer casing, in the form of mineral wool or metal wool such a steel wool or the like. ;The invention also relates to a method of manufacturing such an exhaust pipe, particulary the inner pipe therefor. ;The known technology is represented by Swedish Patents No. 73 11 076-9 and No. 85 00 785-4 and British Patent No. 1 191 125. ;According to the known technology the basic idea is to produce a bendable exhaust silencer, but the previous designs have several drawbacks both as regards manufacture and also as regards forming the exhaust pipe to the desired shape to fit a particular model of vehicle. ;It should be mentioned at this stage that although the exhaust pipe is particulary suitable for use in motor vehicles, other applications are perfectly feasible, e.g. ventilation systems or other fluid channel systems. ;One object of the invention is to provide a new exhaust silencer and a new method of manufacturing it, and also to offer a method for quickly and easily manufacturing an exhaust pipe which as well as being bendable to the desired shape, is also able to substantially maintain its axial length when bent, and even maintain its cross section. Further aims and advantages of the invention are revealed in the following description or will be obvious to one skilled in the art who studies the description. ;(followed by Page 2) ;J KJ K ■ /( ;' L. / J "I 4 ;roq .* a m According to the invention, there is provided an exhaust silencer comprising: an inner, flexible pipe that has an inlet and an outlet, that is permeable to gas in the radial direction and that is formed of perforated rings of strip material joined together axially, the rings when considered in the axial direction having an intermediate portion of smaller diameter than the end portions to provide an outwardly concave cross-section, the diameter of each ring at one end being less than the diameter of the ring at the opposite end and the rings being flexibly connected to one another with the end of one ring that has the larger diameter overlapping the end of the adjacent ring that has the smaller diameter; and an outer casing to seal the outer surface of the flexible pipe.

The pipe sections of the inner pipe are preferably connected together by means of upsetting, to form a joint of the ball-and-socket type.

The casing preferably consists of a curable material and is deformable prior to curing. It may comprise at least one layer produced from a strip material wound helically with partial overlap, e.g. metal strip material, with a curable adhesive between turns in the overlap region. The casing may be arranged to be cured by the heat from the exhaust fumes after assembly in a motor vehicle. Alternatively the curable material may be arranged to be cured by air moisture or the like, in which case the exhaust silencer is provided immediately after manufacture with an air-tight wrapping intended to prevent premature hardening of the curable material.

The invention also provides a method for manufacturing an exhaust silencer in which an inner, flexible pipe, that is permeable to gas in the radial direction, is provided with a casing; comprising manufacturing perforated, generally cylindrical rings out of strip material, the rings when considered in the axial direction having an intermediate portion EA//of smaller diameter than the end portions to provide an or^j end being less than the diameter of the ring at the opposite the diameter of each ring at 1992 " end, the rings being placed axially beside each other and being flexibly jointed to each other by the end of one ring having the larger diameter being upset over the end of the adjacent ring having the smaller diameter.

The cross-sectional structure of the pipe sections and said upsetting are designed to create a joint of ball-and-socket type. Suitable adjustment of the upset will offer a certain friction in the joint designee -s permit deformation of the pipe to the desired shape, the exhaust pipe thus obtaining a suitable shape for its proposed location. The exhaust pipe can thus easily be fi"ec ir.c subsequently fixed permanently. According to a preferred embodiment, the exhaust pipe is made curable by means, for instance, of a curable material, so that its final shape is only fixed after the exhaust pipe has been fitted in its place of application. Curing may be arranged in conventional manner by means of heat from the exhaust fumes flowing through the pipe, or by means of moisture in the atmosphere surrounding the fitted exhaust pipe.

The invention will be described by way of example with reference to the accompaying drawing illustrating an embodiment shown only schematically.

Figure 1 shows schematically an axial section through the inner pipe in the exhaust pipe according to the invention, at the time of manufacture of this inner pipe, and 1 6 JArH992.;;,: / ' Figure 2 shows schematically an axia_ section through an exhaust pipe according to the invention.

Referring first to Figure 2, it can be seen that the exhaust pipe according to the invention comprises an inner pipe 2, radially permeable to gas, a casing 4 surrounding the pipe 2 and a noise-suppressing material 3 arranged between the pipe 2 and the casing 4.

The pipe 2 shown in Figure 1 is produced from generally cylindrical rings 10 of metal strip material. Seen in axial section, the rings have an outwardly concave cross section 5, the ends 6,7 being of different diameter. The end of a new ring with larger diameter is passed over the end with smaller diameter on an adjacent ring, in the direction of the arrow 11. The erxi 6 of larger diameter is then shrunk over the end 7 of smaller diameter of the adjacent ring by means of a radially inwardly directad upsetting operation indicated by the arrows 12. Repetition of this process will gradually produce a pipe 2 of desired length. The ends 6, 7 are dimensioned and shaped to give a joint of ball-and-socket type when subjected to the radial upsetting operation, thus allowing angular adjustment of adjacent rings 10 in relation to each other without substantially altering their axial distance from each other. As shown in Figure 1, the rings 10 are provided with multiple perforations 8.

Referring again to Figure 2, the exhaust pipe is produced by possibly providing the prefabricated pipe 2 externally with a noise-suppressing material 3, such as a layer of mineral wool, steel wool or the like, possibly in the form of an unbroken layer, and then applying a casing 4. In the example shown the casing 4 comprises a thin metal strip 41 wound helically with overlap 42 between adjacent turns. _ t c •// The strip 41 is provided at least in the overlap region °, 16 JAN 1992 229544 with a curable adhesive 43. The adhesive may be of thermosetting type. It will then harder., chus solidifying the casing 4 and consequently the whole exhaust system, after the latter has been bent to the desired shape and fitted in the intended position, e.g. on a motor vehicle.

If the exhaust pipe is to be used where it will not be subjected to sufficient heat to cure suitable adhesives, a curable adhesive can be used of a type which hardens under the influence of a component from the surrounding athmos-phere, such as moisture. However, in this case the exhaust pipe should be provided with an air-tight wrapping immediately after manufacture, to prevent premature hardening. 'r> <992.-'; ^ 2 9 5 -i 4

Claims

WHAT WE CLAIM IS;

1. An exhaust silencer comprising: an inner, flexible pipe that has an inlet and an outlet, that is permeable to gas in the radial direction and that is formed of perforated rings of strip material joined together axially, the rings when considered in the axial direction having an intermediate portion of smaller diameter than the end portions to provide an outwardly concave cross-section, the diameter of each ring at one end being less than the diameter of the ring at the opposite end and the rings being flexibly connected to one another with the end of one ring that has the larger diameter overlapping the end of the adjacent ring that has the smaller diameter; and an outer casing to seal the outer surface of the flexible pipe.

2. An exhaust silencer according to claim 1 further comprising a noise suppressing material between the pipe and the outer casing.

3. An exhaust silencer according to claim 1 or claim 2 in which the axial dimension of each ring is less than its inner diameter.

4. An exhaust silencer according to any one of claims 1 to 3 in which the cross-sectional profile and joint upsets of the rings are arranged to form a joint between each pair of adjacent rings of the ball-and-socket type.

5. An exhaust silencer according to any one of claims 1 to 4 in which the casing consists of a curable material and is deformable prior to curing.

An exhaust silencer according to any one of claims 1 to 5 "in which the casing comprises at least one layer produced from a ' Q C c. y J ;4 - 7 - strip material wound helically with partial overlap, with a curable adhesive between the turns in the partial overlap of the strip.

7. An exhaust silencer according to claim 5 or claim 6 in which the casing is arranged to be cured by the heat from the exhaust fumes passing through the exhaust silencer.

8. A method for manufacturing an exhaust silencer in which an inner, flexible pipe, that is permeable to gas in the radial direction, is provided with a casing; comprising manufacturing perforated, substantially cylindrical rings out of strip material, the rings when considered in the axial direction having an intermediate portion of smaller diameter than the end portions to provide an outwardly concave cross-section, the diameter of each ring at one end being less than the diameter of the ring at the opposite end, the rings being placed axially beside each other and being flexibly jointed to each other by the end of one ring having the larger diameter being upset over the end of the adjacent ring having the smaller diameter.

9. A method according to claim 8 in which the rings are shaped and upset to form a joint of ball-and-socket type.

10. A method according to claim 8 or claim 9 in which the casing is produced from a strip-shaped material wound helically with partial overlap, and a curable adhesive is arranged in the overlap region, the adhesive being allowed to harden to stabilize the exhaust silencer once it has been given the desired shape.

11. An exhaust silencer according to claim 1 and substantially as described in this specification with reference to the 9.ccompanying drawings. , V [l^/9 r-Vl oil DORCHESTER ENTERPRISES LTD \ ^ 8/992^/7 BY Their Attorneys * ./ BALDWIN, SON & CA£EY;'*