GB2027484A

GB2027484A - Silencer for internal combustion engines, compressors or the like

Info

Publication number: GB2027484A
Application number: GB7929081A
Authority: GB
Original assignee: Sulzer AG; Gebrueder Sulzer AG
Current assignee: Sulzer AG
Priority date: 1978-08-21
Filing date: 1979-08-21
Publication date: 1980-02-20
Also published as: JPS5564110A; FR2434266A1; IT1122788B; DE2931544A1; SE7906658L; IT7925152A0; ES483494A1

Abstract

A silencer for internal combustion engines, compressors or the like, has spiral passages (26, 28, 30) each defined by a spiral wall (16), which may be common to all the passages, and arranged side by side, the passages being separated tiled by walls 22, 24 which are transverse to the axis of the spiral and which have apertures (20) connecting the passages, the apertures (20) being immediately adjacent the surface (17) of the spiral wall 16. <IMAGE>

Description

SPECIFICATION Silencer for internal combustion engines, compressors or the like This invention relates to a silencer for internal combustion engines, compressors or the like, comprising at least two passages extending in the form of a spiral, arranged side by side and separated by a wall which is transverse to the axes of the spirals and connecting the passages.

Silencers of this kind are disclosed, for example, in U.S. Patent Specification No.

1,658,126. The apertures disposed in the transverse wall separating the spiral passages are largely disposed along the centre line of the passage.

The disadvantage of this known silencer is that it has an inadequate silencing action.

The object of the invention is so to improve the above silencer as to give satisfactory silencing for practical use.

Accordingly the present invention provides a silencer particularly for internal combustion engines, compressors or the like, having at least two spiral passages each defined by a spiral wall and arranged side by side being separated by a wall which is transverse to the axes of the spirals and has apertures connecting the passages, the apertures being immediately adjacent the surfaces of the spiral wall of the passages.

It has surprisingly been found that this configuration gives an improvement to the silencing of more than about 10 dBA, in comparison with an otherwise identical silencer having the apertures substantially in the middle of the passage.

According to one particularly advantageous construction of the invention, a spiral outlet passage and may be provided on each side of a spiral inlet passage. This gives a considerable additional silencing action as compared with a silencer having two spiral passages extending side by side.

According to another advantageous embodiment of the invention, a radial end wall may be provided on the entry end of the inlet passage a throttle be provided on the outlet end of the outlet passages. This simplifies the configuration of the silencer for production purposes, e.g. as a casting. The throttle allows the gas outflow to be controlled.

According to another aspect of the invention, the spiral wall defining the passages may have turbulence members which provide additional turbulence in the gas flow and this has a positive effect on silencing.

In another advantageous embodiment of the invention, a pipe may follow the outlet passage. As a result, the silencer can be fitted directly after the engine. The pipe provides an additional equalization of the flow with a silencing action.

In a development of the invention, the width of the apertures as considered in a transverse direction may be about one-third of the passage width maximum. This gives optimum silencing of the gases in the associated passage.

In order to promote a fuller understanding of the above and other aspects of the present invention, some embodiments will now be described, by way of example only, with reference to the accompanying drawings in which Figure 1 is a plan view of a silencer with separately shown outer side walls, in partial section on the line I-I in Fig. 2, and Figure 2 is a side elevation on the line Il-Il in Fig. 1.

In the drawings a silencer is shown having a casing 10 (Fig. 1) having an inlet 12 and an outlet 14 and divided into three spiral passages 26, 28 and 30 extending side by side, which are defined by means of a spiral wall 1 6 having wall surfaces 15, 17, and separated by two walls 22, 24 which extend transverse to the axis 1 8 of the spiral and have apertures 20. The passages 26, 28 and 30 are interconnected by holes 32, 34 disposed at the centre of the walls 22, 24. A generally radial end wall 36 is provided at the entry to the passage 26 in the casing 10 while on the outlet the passages 28 and 30 lead into a common exit chamber 37 having a slot which acts as a throttle 38 in the form of a protrusion on the outer wall of the casing 10, and which chamber extends over the entire casing width.The wall 1 6 bounding the associated passage in the direction of the spiral axis has projections 40 which act as turbulence creating members. The casing covers 42, 44, which are shown separately of the casing 10, are fixed by screws (not shown), which are screwed into the tapped holes 46. As will be seen from Figs. 1 and 2, the apertures 20 are immediately adjacent the surface 1 7 of the wall 1 6 bounding the associated passages 26, 28 and 30. The transverse width a (Fig. 2) of the apertures 20, is advantageously approximately one-third of the passage width b (Fig.

2).

The operation of the system described is as follows: The gases fed to the inner passage 26 in the direction of arrow 48, e.g. via inlet 12, flow in the direction of arrows 66, 68 along the spiral wall 1 6 to the spiral axis 1 8 and through the holes 32, 34 in the direction of arrows 50, 52 into the outer passages 28, 30, which act as outlet passages, and then in the direction of arrows 56, 58, 60 via the outlet chamber 37 which is common to these passages and which is provided with the throttle 38, through the outlet 14 in the direction of arrow 54 into atmosphere or into a following pipe. The directions of flow in the passages 28, 30 are thus in opposition to the direction of flow in the passage 26. The passage apertures 20 allow communication between the gas flows. An additional silencing effect is obtained by the turbulence members 40 and the throttle 38.

Claims

1. A silencer particularly for internal combustion engines, compressors or the like, having at least two spiral passages each defined by a spiral wall and arranged side by side, being separated by a wall which is transverse to the axes of the spirals and has apertures connecting the passages, the apertures being immediately adjacent the surfaces of the spiral wall of the passages.

2. A silencer as claimed in Claim 1, comprising three such spiral passages, two of them being outlet passages and disposed one on each side of the third which is an inlet passage.

3. A silencer as claimed in Claim 1 or 2, in which an end wall is provided at the entry to one of the spiral passages which is an inlet passage and a throttle is provided at the outlet from the other passage or passages which are outlet passages

4. A silencer as claimed in Claim 1, 2 or 3, in which the spiral wall or walls defining the passages is formed with turbulence creating members.

5. A silencer as claimed in Claim 2, 3 or 4, in which the outlet passage or passages is or are followed by a pipe.

6. A silencer as claimed in any preceding claim, in which the transverse width of the apertures is one-third of the transverse width of the passages.

7. A silencer as claimed in any preceding claim in which a common spiral wall defines all said spiral passages.

8. A silencer particularly for internal combustion engines, compressors or the like, substantially as herein described with reference to the accompanying drawings.