CA2094168C - Mufflers - Google Patents
Mufflers Download PDFInfo
- Publication number
- CA2094168C CA2094168C CA 2094168 CA2094168A CA2094168C CA 2094168 C CA2094168 C CA 2094168C CA 2094168 CA2094168 CA 2094168 CA 2094168 A CA2094168 A CA 2094168A CA 2094168 C CA2094168 C CA 2094168C
- Authority
- CA
- Canada
- Prior art keywords
- helicoid
- longitudinal axis
- plate
- tube
- acute angle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/18—Construction facilitating manufacture, assembly, or disassembly
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N1/00—Silencing apparatus characterised by method of silencing
- F01N1/08—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling
- F01N1/12—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling using spirally or helically shaped channels
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Exhaust Silencers (AREA)
Abstract
A sound attentuating device, typically applied to the exhaust of internal combusion engines, and consisting of a helicoidal element fitted snugly within a tube. The helicoid is formed by a sequence of flat triangular sufaces generated by a forward fold transverse to a longitudinal axis followed by a reverse fold oblique to the longitudinal axis and having the procedure repeated. It is analogous to an accordion-like strip which rotates because an oblique fold alternates with a transverse fold. The muffler functions by having the helicoid reflect sound waves generated within the machine to which it is attached while permitting the escape of gases through the tube in a spiral manner.
Description
~~~ .416 The invention relates in general to noise reduction devices and more particularly to noise reduction devices commonly referred to as mufflers, silencers or resonators, which are placed in the exhaust stream of motorcycles, cars, all types of internal combusion engines, dust collectors, vacuum cleaners, compressors and air, gas or steam actuated machines, because unmuffled noises are not only terribly distracting, but may pro-duce permanent hearing loss. In this context, the term "muffler'°
embraces all sound attenuating devices placed in exhaust systems.
Therefore, an object of the invention is to provide for noise reduction from the exhaust of machines.
Another object of the invention is to provide a muffler for the purpose of noise reduction.
Another object of the invention is to provide an element to be inserted into an exhaust pipe or tail pipe for the purpose of noise reduction.
Another object of the invention is to eliminate the muffler as a separate component in the exhaust system of machines.
Other objects and a fuller comprehension of the invention may be had by examining the following description and claims together with the attached drawings in which Fig. I is a front elevation of the helicoid element:
Fig. II is a sectional side elevation.
Fig. III is an assembly view of helicoid element in a tube.
Mufflers are of two types. In the first type sound waves travel throught a labyrinth interspersed with baffles. The second type of muffler consists of a perforated tube placed within a second tube having end cups. The latter is sometimes called a Helmholtz resonator.
The new muffler which is the subject of this invention consists of a single helicoid element located within a tube and having a snug fit. The helicoid functions by reflecting sound waves generated within the machine, while permitting gases to _ 1 _ ~09~~~~
flow through the tube in a spiral manner.
In a motorcycle or motorized toboggan the helicoid element may be placed in the exhaust tube, thus eliminating the muffler as aseparate component. In an automobile'or truck, the helicoid element may be placed in the tail pipe, thus eliminating the muffler as a separate component. It follows that the helicoid element may be placed in a length of tubing in order to produce a muffler as a separate component.
With reference to the drawings, Fig.I shows a helicoid ele-ment generated by a sequence of adjacent triangles. In contrast, one may consider the smooth continuously varying helicoid, which contains no triangles and is generated by lines parallel to a horizontal plane XOY, which intersect the vertical ~ axis and the circular helix and expressed by the equations ~ = c,tan ly/x where c=a tan A, (BELL,Robert John. An Elementary Treatise on Coordinate Geometry of Three Dimentions. 3rd edition, London, 1960.) The two above helicoids may be considered as species belonging to the same genus.
In Fig.JA, numbers 6 to 19 represent a sequence of trian-gles, or triangular plates. The corner of 'the triangle BCK
appears to be clipped or blunted at K. This is deliberately done to show limitations that might exist in manufacturing.
When the helicoid is made of steel by bending along line C F, intergranular distortion takes place within the material along line C F and work-hardening ensues. Similar effects will occur when bending takes place along line BG. Should the point G coincide with the point F unacceptabJ.e distortions may result.
However, for all practical purposes the point G approaches the point F ever so closely so that the polygon BCFG is triangular and approaches the triangle BCK. When the helicoid is produ-ced by casting or injection moulding, this distinction is un-necesary.
With reference to the drawing in Fig. I, consider the tri-angle-generated helicoid to be made of steel. A strip of steel is pulled off a coil and fed through a modified press brake.
The line of travel of the material is along the longitudinal axis XY. The downward motion of the horn of the press brake will fold the strip of metal first along a line perpendicular to the line of travel. Such a downward fold takes place along the line CF and along all lines parallel to CF, each in its own time. In this manner plate 12 is folded at right angle to plate 11, along the line CF. This angle is shown as BCD.
The horn of the press brake is tapered from the edge which makes contact with BC to the edge which makes contact with GF.
Towards the end of the rotational travel of the horn, the sheet metal strip is forced upward from a lip or recess to form ano-ther right angle between the plates 13 and 12 along the oblique line BG and shown as angle HGF. Hence, while plate 12 is forced down-ward plate 13 is forced upward. This takes place in a single stroke. The mate-rial is then advanced and the operation repeated.
The taper in the horn which .produced the fold along the oblique line BG generates a right-hand helicoid. When the taper on the horn is reversed to initiate a fold from paint C
to point H a left-hand helicoid is generated. Both left-hand and right-hand helicoids are useful. The thickness of the material as indicated by L,M and N in Fig.I helps to make clear the right-hand helicoid.
When the oblique line BK and adjacent line CK are pro-jected on to a plane perpendicular to XY, BK is equal in length to CK. Thus the triangle BCK in Fig.I when rotated produces the isoscles triangle BCK an Fig. TI. A11 oblique lines when coupled with adjacent lines will have this' effect. The isocles configuration is desirable for three-point contact within the tube.
An examination of Fig. II shows approximately thirteen tri-angular plates. The same numbered plates are seen in Fig.I as comprising one half a turn and stretch from plate 6 to plate 19. If the triangular segments of Fig.II were re-arranged on to a plane surface, they would form half a circle having BK as radius. Then each segment would have a pointed end of 180°/13=
13.8°. Thus angle BKC in Fig. II :is about 13.8°. Rotate tri-angle BCK to Fig.I and angle BKC becomes approximately i5°.
All acute angles in Fig. I, such as angle BKC axe approxi-mately 15° each. The employment of 15° has performed very well for models built and tested. When the angle BKC is much larger than 15°, a correspondingly large circular gap will be obtained between the chord BC and all similar chords defined as BnCn and the inner curve of the tube in which the helicoid is installed.
When the angle BKC is much smaller than 15° a larger number of plates are required to generate the same twist. Changes in the size of angle BKC and orientation of angle BKC with regard to axis XX will produce changes in the lengths of BK and CK.
The invention comprehends all changes and variations to the helicoid that may be produced by angular variations and the extent of folding of plates. In~the present invention, the helicoid is firmly fixed in the tube by friction or other means.
r - Additionally, the same helicoid, loosely fitted in a tube and having means of rotation becomes a screw conveyor with the ad-i vantages of low cost since there is no longitudinal shaft, and possesses the flexibility to go around bends.
i Much of the above disclosure has been presented with con-i cern for details of structure and of combination of parts so as :e to provide a clear and cogent picture. However, it is under-stood that changes in details of structure, including varia-tions, combinations and angularity of parts, methods of manu-facture, choice of material and its application may be resorted ., to, as being consistent with the spirit and scope of the inven-:i a '; tion as claimed.
-
embraces all sound attenuating devices placed in exhaust systems.
Therefore, an object of the invention is to provide for noise reduction from the exhaust of machines.
Another object of the invention is to provide a muffler for the purpose of noise reduction.
Another object of the invention is to provide an element to be inserted into an exhaust pipe or tail pipe for the purpose of noise reduction.
Another object of the invention is to eliminate the muffler as a separate component in the exhaust system of machines.
Other objects and a fuller comprehension of the invention may be had by examining the following description and claims together with the attached drawings in which Fig. I is a front elevation of the helicoid element:
Fig. II is a sectional side elevation.
Fig. III is an assembly view of helicoid element in a tube.
Mufflers are of two types. In the first type sound waves travel throught a labyrinth interspersed with baffles. The second type of muffler consists of a perforated tube placed within a second tube having end cups. The latter is sometimes called a Helmholtz resonator.
The new muffler which is the subject of this invention consists of a single helicoid element located within a tube and having a snug fit. The helicoid functions by reflecting sound waves generated within the machine, while permitting gases to _ 1 _ ~09~~~~
flow through the tube in a spiral manner.
In a motorcycle or motorized toboggan the helicoid element may be placed in the exhaust tube, thus eliminating the muffler as aseparate component. In an automobile'or truck, the helicoid element may be placed in the tail pipe, thus eliminating the muffler as a separate component. It follows that the helicoid element may be placed in a length of tubing in order to produce a muffler as a separate component.
With reference to the drawings, Fig.I shows a helicoid ele-ment generated by a sequence of adjacent triangles. In contrast, one may consider the smooth continuously varying helicoid, which contains no triangles and is generated by lines parallel to a horizontal plane XOY, which intersect the vertical ~ axis and the circular helix and expressed by the equations ~ = c,tan ly/x where c=a tan A, (BELL,Robert John. An Elementary Treatise on Coordinate Geometry of Three Dimentions. 3rd edition, London, 1960.) The two above helicoids may be considered as species belonging to the same genus.
In Fig.JA, numbers 6 to 19 represent a sequence of trian-gles, or triangular plates. The corner of 'the triangle BCK
appears to be clipped or blunted at K. This is deliberately done to show limitations that might exist in manufacturing.
When the helicoid is made of steel by bending along line C F, intergranular distortion takes place within the material along line C F and work-hardening ensues. Similar effects will occur when bending takes place along line BG. Should the point G coincide with the point F unacceptabJ.e distortions may result.
However, for all practical purposes the point G approaches the point F ever so closely so that the polygon BCFG is triangular and approaches the triangle BCK. When the helicoid is produ-ced by casting or injection moulding, this distinction is un-necesary.
With reference to the drawing in Fig. I, consider the tri-angle-generated helicoid to be made of steel. A strip of steel is pulled off a coil and fed through a modified press brake.
The line of travel of the material is along the longitudinal axis XY. The downward motion of the horn of the press brake will fold the strip of metal first along a line perpendicular to the line of travel. Such a downward fold takes place along the line CF and along all lines parallel to CF, each in its own time. In this manner plate 12 is folded at right angle to plate 11, along the line CF. This angle is shown as BCD.
The horn of the press brake is tapered from the edge which makes contact with BC to the edge which makes contact with GF.
Towards the end of the rotational travel of the horn, the sheet metal strip is forced upward from a lip or recess to form ano-ther right angle between the plates 13 and 12 along the oblique line BG and shown as angle HGF. Hence, while plate 12 is forced down-ward plate 13 is forced upward. This takes place in a single stroke. The mate-rial is then advanced and the operation repeated.
The taper in the horn which .produced the fold along the oblique line BG generates a right-hand helicoid. When the taper on the horn is reversed to initiate a fold from paint C
to point H a left-hand helicoid is generated. Both left-hand and right-hand helicoids are useful. The thickness of the material as indicated by L,M and N in Fig.I helps to make clear the right-hand helicoid.
When the oblique line BK and adjacent line CK are pro-jected on to a plane perpendicular to XY, BK is equal in length to CK. Thus the triangle BCK in Fig.I when rotated produces the isoscles triangle BCK an Fig. TI. A11 oblique lines when coupled with adjacent lines will have this' effect. The isocles configuration is desirable for three-point contact within the tube.
An examination of Fig. II shows approximately thirteen tri-angular plates. The same numbered plates are seen in Fig.I as comprising one half a turn and stretch from plate 6 to plate 19. If the triangular segments of Fig.II were re-arranged on to a plane surface, they would form half a circle having BK as radius. Then each segment would have a pointed end of 180°/13=
13.8°. Thus angle BKC in Fig. II :is about 13.8°. Rotate tri-angle BCK to Fig.I and angle BKC becomes approximately i5°.
All acute angles in Fig. I, such as angle BKC axe approxi-mately 15° each. The employment of 15° has performed very well for models built and tested. When the angle BKC is much larger than 15°, a correspondingly large circular gap will be obtained between the chord BC and all similar chords defined as BnCn and the inner curve of the tube in which the helicoid is installed.
When the angle BKC is much smaller than 15° a larger number of plates are required to generate the same twist. Changes in the size of angle BKC and orientation of angle BKC with regard to axis XX will produce changes in the lengths of BK and CK.
The invention comprehends all changes and variations to the helicoid that may be produced by angular variations and the extent of folding of plates. In~the present invention, the helicoid is firmly fixed in the tube by friction or other means.
r - Additionally, the same helicoid, loosely fitted in a tube and having means of rotation becomes a screw conveyor with the ad-i vantages of low cost since there is no longitudinal shaft, and possesses the flexibility to go around bends.
i Much of the above disclosure has been presented with con-i cern for details of structure and of combination of parts so as :e to provide a clear and cogent picture. However, it is under-stood that changes in details of structure, including varia-tions, combinations and angularity of parts, methods of manu-facture, choice of material and its application may be resorted ., to, as being consistent with the spirit and scope of the inven-:i a '; tion as claimed.
-
Claims (12)
1. A helicoidal element generated by a sequence of congruent triangular plates, each having an acute angle located at the external longitudinal edge of the helicoid, said acute angle lying, within the triangular plate or when said triangular plate is truncated to form a trapezoidal plate, said acute angle becomes a projection beyond said trapezoidal plate and having said acute angle alternate from one longitudinal outer edge to tire opposite long-itudinal outer edge with said plates arranged along a longitudinal axis in such a manner that each plate is perpendicular to the adjacent plate said perpendicularity alternating from negative to positive with respect to the longitudinal axis, wherein each plate is joined to the adjacent plate by a shared longest edge on one side and by the shared second longest edge on the outer side, the second longest edge being perpendicular to the longitudinal axis and the third side which is the shortest, forming the outer edge of the helicoid and parallel to the longitudinal axis.
2. A helicoidal element for a muffler as described in Claim 1 and generated by a sequence of congruent triangular plates, each plate having an acute angle of 15° plus or minus 7°, enclosed by the two longest sides of said triangular plate and with said acute angle located at the longitudinal outer edge of the helicoid and alternating from one outer edge to the opposite outer longitud-inal edge of the helicoid.
3. A helicoidal element generated by a sequence of congruent trapezoidal plates formed geometrically truncating the acute angle from the triangular plate as described in Claim 2, thereby making opposite longitudinal outer edges of the trapezoid parallel, as well as being the two shortest sides of the trapezoid, said trapezoidal plates arranged along the longitudinal axis in such a manner that each plate is virtually perpendicular to its adjacent plate, said perpendicularity alternating from negative to positive with respect to the longitudinal axis, and each trapezoidal plate is attached to the adjacent trapezoidal plate by sharing the common longest edge on one side and sharing the second longest edge on the opposite, the second longest edge being at right angle to the longitudinal axis and the two shortest edges form-ing the parallel sides of the trapezoid, said shortest sides being concomitant with the longitudinal outer edges of the of the helicoid and parallel to the longitu-dinal axis.
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4. A helicoidal element for a muffler, generated by a sequence of congruent trapezoidal plated formed geometrically by truncating the acute angle portion from a triangle whose acute angle projection of approximately 15° is located outside of the longitudinal outer edge of the helicoid thereby making the opp-osite longitudinal outer edges of the trapezoid parallel as well as being the tow shortest sides of the trapezoid, said trapezoidal plates being arranged along the longitudinal axis in such a manner that each plate is perpendicular to its adjacent plate, said perpendicular alternating from negative to positive with respect to the longitudinal axis, each plate being joined to its adjacent plate by a shared longest edge on one side and by the shared second longest edge on the opposite side, the projected acute angle between the two longest sides being 15°~7° while the two shortest sides form the parallel edges of the trapezoid said shortest sides being conco-mitant with the longitudinal outer edges of the helicoid and are parallel to the longitudinal axis.
5.A process of manufacturing a helicoid by bending a ribbon-like strip of material substantially at right angle to the ribbon-like strip and transverse to the longitudinal axis to be followed by a second bend in a direction opposite to the previous bend with the resulting two planes form-ing an angle of approximately 90°, the second bend being along a line oblique to the first bend so that the lines of the first bend and the second bend meet at one of the longitudinal outer edges of the material to produce a triangular plate having a acute angle of 15° at said longitudinal outer edge of the material with the material being advanced to repeat the bending sequence, consequently the acute angle of 15° now shifts to the opposite longitudinal edge of the material, meanwhile maintaining the procedure of forward and reverse bends along transverse and oblique lines in a continuous manner such that the oblique line generates the twist to form the helicoid while the transverse line maintains propagation along the longitudinal axis.
6. A muffler comprising in combination the helicoidal described in Claims 1, 2,3,or 4 and a tube, said helicoid to be centrally located within the tube, both helicoid and tube having the same longitudinal axis with a slide fit between helicoid and tube so as to have such interference that helicoid and tube will be held fast by friction, swaging, circumferential deformation or similar means.
7. A muffler comprising in combination the helicoid described in Claims 1, 2,3 or 4 and a exhaust pipe as found on internal combustion engines or compressors,said helicoid to be centrally located within said exhaust pipe, both helicoid and exhaust pipe having the same longitudinal axis, and with a slide fit between helicoid and exhaust pipe so as to have such interference that helicoid and exhaust pipe will be held fast by friction, swaging, circum-ferential deformation or similar means.
8. A muffler comprising in combination a helicoid as described in Claims 1, 2, 3, or 4 and a tail-pipe, said to be centrally located within the tail-pipe, both helicoid and tail-pipe having the same longitudinal axis and with a slide fit between helicoid and tail-pipe so as to have such interfer-ence between helicoid and tail-pipe that helicoid and tail-pipe will be held fast by friction, swaging, circumferential deformation, longitudinal deform-ation or other means.
9. A muffler comprising in combination a helicoid as described in Claim 1, 2, 3,or 4 with means for reflecting sound waves back to engine or exhaust manifold and a tube, said helicoid to be centrally located within the tube with such interference as to be held fixed by friction or other means, and said combination having means to provide a spiral passage for the emission of exhaust gasses.
10. A mechanism comprising in combination the helicoid described in Claim 1, and a tube, said helicoid to be centrally located within the tube.
11. A mechanism comprising in combination the helicoid described in Claim 3, and a tube, said helicoid to be centrally located within the tube.
12. A helicoid as described in Claims 1, 2, 3, 4 or 5 having a sectional diameter ranges from 1/2 inch to 15 inches is claimed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2094168 CA2094168C (en) | 1993-04-16 | 1993-04-16 | Mufflers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2094168 CA2094168C (en) | 1993-04-16 | 1993-04-16 | Mufflers |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2094168A1 CA2094168A1 (en) | 1994-10-17 |
| CA2094168C true CA2094168C (en) | 2003-05-06 |
Family
ID=4151473
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2094168 Expired - Fee Related CA2094168C (en) | 1993-04-16 | 1993-04-16 | Mufflers |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2094168C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3884143B1 (en) * | 2019-01-29 | 2022-11-16 | Teknologian tutkimuskeskus VTT Oy | A sound attenuator as well as elements and a method of production thereof |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113763914A (en) * | 2021-09-27 | 2021-12-07 | 哈尔滨理工大学 | Spiral Helmholtz resonator |
-
1993
- 1993-04-16 CA CA 2094168 patent/CA2094168C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3884143B1 (en) * | 2019-01-29 | 2022-11-16 | Teknologian tutkimuskeskus VTT Oy | A sound attenuator as well as elements and a method of production thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2094168A1 (en) | 1994-10-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |