FR2498680A1 - Noise damping insert for exhaust pipe - comprises spiral wound rigid strip with blind punched holes to regularise flow - Google Patents

Abstract

The damping device is incorporated on the internal surfaces of a conduit such as an automobile exhaust pipe, serving to regularise the flow of fluids under fluctuating pressures or to maintain the uniform flow of fluids under constant pressures. It breaks up the shock waves by reducing the contours and regularising the flow. The device comprises a spiral wound rigid strip which is installed in the pipe. The surface of the strip may incorporate open punched holes pointing in the same direction forming small blind recesses facing the flow of gas. The recesses may be formed in the walls of the pipe itself, and may have perforated internal surfaces.

Description

The present invention relates to exhaust pipes
allowing the transfer of burnt gases from an explosion engine
with the minimum of obvious noises characteristic at the exit
tie; It also concerns the transport of liquid masses
under pressure in tubes or "pipes" and makes it possible to avoid pipes
the unexpected and brutal blows.

In the known devices of this enre, partitions and
baffles, arranged inside the pipe or conduit, try
dampen the shock of detonations and attenuate the sounds; For
more efficiency we often bring relaxation pots auxi ##
liaries, and with regard to the transport of liquid masses
we have to add to the circuit, for safety, vases
or expansion chambers or "regulators". Such devices
are bulky, heavy and expensive.

The device according to the invention makes it possible to avoid these inconveniences.
clients; In it, in fact, it becomes possible to trans-
fdre the burnt gases, or other fluids, without noise or risk.

The device, object of the invention, always includes a
system of small chapels or rooms, multiple, and oriented * against the current, the design of which is such that it forces waves
shock to split endlessly Until fully diluted.

 This system can be made directly from the walls.

 of the duct, by taking up the material.

It can be judged easier, and for questions of pre
cision too, to bring in an external element, sort of
rigid ribbon (I) which has been honeycombed using a "râ" type technique
cheese pe "or" with vegetables ", which ribbon developed in spirals
is forced into the conduit (2) in a bare manner
spi-res are applied well on the wall thereof and that each
alveolus (3), just now open on two sides Dar construc
tion, has indeed closed at its base by position; Kind of
small cave, face facing upstream.

In the case of the engine: When the explosions repel the
vegues of gas burned one after the other, these must meet, obstructing the circumference of the
duct, the multiple small caves counter-oriented, do-
health front. The waves, in successive waves are broken up, sort of grated; They are reduced in intensity and multiplied by as much in minute values; Finally they are mixed, as the progression progresses, in a vortex (helical) movement which favors, downstream, step by step, the renewal of the laminar wear process; And so on until the exit where only a settled, regular, continuous breath appears.

 In the case of the transport of a liquid in tube or "pipe" the multiple small caves against oriented act in the same way to regulate the current and to counter, from the start, any attempt of spontaneous phenomenon # of local overpressure; Each of the chambers acting as a micro-regulator prevents the birth of the famous shock waves and vibrational phenomena which are always ready to arise and which are the source of brutal, devastating shocks to the conduit.

 The device which is the subject of the invention can be used in all cases where it is sought to reduce, or even cancel, the nuisances originating from an untimely sound source; Particularly interesting applications can be the improvement of old exhaust pipes or, better, the manufacture, in the automotive industry, of a new generation of these, less bulky and better suited to modern vehicles, low on the road and flat floors.

 The same device may be required in all cases where it is sought to suppress the parasitic appearance of the formidable resonances and other "water hammer" in the transport under pressure of liquids in heavy pipes. Particularly interesting applications can then be the improvement of old conduits or the construction of new modules that are less expensive to manufacture or have assembled.

Claims (4)

CLAIMS.  1) Device making it possible to regulate, in a conduit, the rhythmic flows of a fluid under alternating pressure, or to insure, in a conduit, the regularity of the flow of a fluid under continuous pressure, without untimely, spontaneous blows, anarchioues,  Characterized by the fact that it has a "damper" incorporated into its walls intended to break the shock waves, attenuate the contours and standardize the flow.  Characterized by a rigid strip (I) arranged in turns which are introduced inside the conduit (2). This ribbon has been previously prepared so as to reveal over its entire surface a multitude of open-celled cutouts (3), directed in the same direction of the "cheese grater" or vegetable "type and whose arrangement is such they automatically form with the walls of the duct, where the tape supports them, closed at the base, as many small caves oriented against the current.  2 = Depreciated according to claim I,  3) Shock absorber according to claim 2,  Characterized by the fact that these caves, chambers or chapels can have come directly on the interior walls of the duct, by taking up the material itself.  4) Caves, Rooms or Chapels, according to claims 2,3,  : Characterized by the fact that their own wall can also be perforated.