FR2492455A1 - Spark arrester silencer for IC-engine - has carbon particles extracted by chicanes cooling by finned tubes in circulating cooling fluid - Google Patents

Abstract

The spark arrestor silencer has a body (1) with gas inlet (2) and exhaust (3) openings and is for an internal combustion engine. There is an internal carbon particle extractor. Around the body is a cover (4) forming an annular space with openings and communicating, by its outlet, with the body entry. In the annular space is a cooling feed for the exhaust gas going across it. The separator is a chicane series of barriers (6), each consisting of two half cones (11,12). Cooling is by finned tubes (25,26) immersed in circulating cooling fluid and twined together.

Description

 The present invention relates to a spark arrester.

 Spark arresters are mainly used on internal combustion or internal combustion engines operating in an oxidizing atmosphere, where the risk of fire is always present. They can also be used on fans or compressors, for example. The function of these spark arresters is to separate the carbonic particles in ignition from the combustion gases of the rotating machines mentioned above, before these escape into a dangerous atmosphere. We already know how to manufacture silent spark arresters, failing to have standard exhaust pipes in series. Attenuation of noise in the spark arrester can thus be achieved by providing a double expansion chamber with long internal connection ducts. In this case as in that where one uses an exhaust pipe, one comes up against the inconvenient due to the space requirement of the device.

 The present invention has its origin in the fact that exchangers are also very often used in an oxidizing atmosphere to lower the temperature of the exhaust gases of these same rotating machines, which, moreover, amplifies the drawback of footprint specified above.

 The present invention therefore aims to provide a spark arrester, which is both silent and compact, and whose "silent" function is provided by means which also provide the heat exchange function ".

 k for this purpose, the present invention relates to a spark arrester comprising a body, provided with inlet and outlet ports for exhaust gas from a rotary explosion or internal combustion machine, and known means arranged in the body for separate the carbon dioxide particles from the exhaust gases, characterized in that there is provided, around the said body, an envelope forming with the said body an annular enclosure provided with inlet and outlet openings and communicating, by its outlet opening, with the inlet orifice of said body 1 and cooling means arranged in the enclosure for cooling the exhaust gases passing through the enclosure from its inlet opening to its outlet opening.

 Thanks to the invention, the spark arrestor separation means being surrounded by the means for cooling the gases, the vibrations and the noises, generally generated at the level. spark arresting means are damped by the cooling means. In other words, the invention relates to a combination of a spark arrester and a heat exchanger which not only performs the functions exerted separately by a spark arrester and an exchanger, but also the "so silent" function provided by a pot of '' exhaust or special means in the spark arrester. In addition, these three functions are ensured by a compact device, the length of which, for example, does not exceed that of known spark arresters and exchangers, for a determined volume of gas to be delivered.

 In addition, the invention also provides the remarkable result of cooling the outer wall of the body itself of the spark arrester and thus preventing the ignition of the outside combustion air.

 Finally, it should be noted that due to the annular shape of the heat exchange enclosure, the exhaust gases are centrifuged as soon as they arrive in the device of the invention and that, like the outlet opening of the enclosure communicates with the inlet of the internal body, the separation of carbon dioxide particles from the exhaust qaz to be treated can already start in this cooling enclosure.

The invention will be better understood using the following description, with reference to the accompanying drawing, in which
- fig. 1 shows a schematic view in longitudinal section of an embodiment of the device of the invention;
- fig. 2 shows a schematic cross-sectional view of the device along line II-II of FIG. 1, and
- fig. 3 shows a schematic sectional view, along the line III-III of FIG. 1, directional vanes.

 The device of the invention shown in FIG. 1 comprises first of all an internal body 1, of generally cylindrical shape, inside which are stacked baffles known but described in more detail below for the separation of carbon dioxide particles from an exhaust gas stream d 'An internal combustion or internal combustion engine, for example, intended to pass through this body 1 from an inlet orifice 2 to an outlet orifice 3, of this body. A skirt 4, of generally cylindrical shape, with a diameter substantially smaller than that of the body 1 is disposed inside this body, between its inlet orifice 2 and the separation baffles, and constitutes an expansion chamber for the gases exhaust entering the body 1. A gas inlet pipe 8, the base of which has the same shape as the inlet orifice 2 of the body i, partially closes with its base, this inlet orifice 2 of the body 1. The cone 8 has, near its base, annular openings 5 for I1 flow, out of the body 1, of carbon dioxide particles separated by the baffles.

 The separation of carbon dioxide particles is carried out using baffles 6 already mentioned, which will now be described. Each baffle 6 has two vents consisting of two half-bends II and 12, the heights of which are arranged along the axis of the body 1 and which are placed on either side of the baffle in opposite directions. The baffles 6 have, near their periphery, holes allowing them to be stacked on rods, for example 9, 10, in FIG. 1. The skirt 4 is fixed to the first baffle 6 closest to the inlet orifice 2 of the body 1. Thus, and in a known manner, the baffles 6 are stacked on each other and placed at a determined spacing , so that the gases, upon entering the stack, meet the edges of the half-cones projecting towards the expansion chamber formed inside the skirt 4. As a result, the gases cannot escape through the outlet 3 of the body 1 only after having been subdivided and having followed several helical paths in a gyratory movement, as shown in broken lines and dashed lines, which causes the separation of carbon dioxide particles from the gas stream, particles which can then flow through the annular openings 5 of the cone 8.

 It is clear that this separation of the carbonic particles by centrifugation of the gases is not limiting of the invention and that one could also provide for separation by impact, in particular.

 The device of the invention further comprises a casing 13, disposed outside and around the body 1, of generally cylindrical shape, extending almost under the inlet orifice 2 of the body 1, by a surface frustoconical 14, delimiting an opening -out of the envelope 13, and a receptacle 15, connected to the surface 14 and arranged to collect and allow the evacuation, or the devatting, of the carbonic particles, by a devatting hatch 72. A cone 16 for retaining carbonic particles is disposed in the receptacle 15, under the inlet cone 8 of the body 1 for separating the particles, and in the same direction as the latter. The casing 13 and the body form an annular enclosure 17, closed, at the lower part, under the body 1, by the receptacle 15 and, at the upper part at the level of the last separating baffle 6 of the body 1, by an annular plate 23, beyond which extends the envelope 13. Two gas inlet 19 and outlet 20 pipes are provided. The connection of the inlet pipe, or opening, is situated in the upper part of the enclosure 17, at the level of the last separation baffles 6, the connection of the outlet pipe being located in the upper part of the casing 13, beyond the outlet orifice 3 of the interior separation body 1 and the annular plate 23 at the level of a gas outlet chamber 24, formed by the casing 13, the annular plate 23 and a closing plate 18 the upper end of the casing 13. The upper part of the enclosure 17 comprises a frustoconical partition 21, to which the inlet pipe 19 is in fact connected, so as to form a gas inlet chamber 22 which be conical.

 Cooling means are arranged in the enclosure 17 and will now be described. They comprise two bundles of tubes with fins 25, 26 parallel, harmoniously distributed over two cylinders 27, 28, respectively, extending over practically the entire length of the body 1, between two annular plates 29, 30 arranged at the levels of the lower part of the inlet chamber 22 and of the inlet cone 8 of the body 1, respectively. Of course, the invention is not limited to such an arrangement, and one could provide either a single bundle of tubes, or, on the contrary, more than two bundles.

The plates 29 and 30 divide the enclosure 17 into three parts, namely the inlet chamber 22, an outlet zone at the frustoconical surface 14, and a heat exchange zone, as will be seen below. -after, located between the two plates 29 and 30. Thanks to the plates 29, and 30, the gases arriving through the chamber 22 are therefore forced to pass through the finned tubes 25, 26. The so-called heat exchange zone of the enclosure 17 communicates with an inlet 40 and an outlet 41 of a fluid, preferably water, cooling, inlet and outlet which are connected to the casing 13, respectively in the lower part and in the upper part of the enclosure or, beyond this enclosure, as shown in FIG. 1 for the water outlet 41. The tubes 25, 26 of the two bundles 27, 28 therefore bathe in the cooling water in circulation and are arranged so that the respective fins of two adjacent tubes are inserted one between the other (Fig. 2), so as to compress the cooling water and thus increase the heat exchange by better friction of the cooling water on the tubes.

 An iconic skirt 50 is arranged around the envelope 13 to form a venturi and, by creating a current of fresh air caused by the phenomenon of hot air ascending, to cool the wall of A envelope 13 and thus entail the surface calories of this envelope.

 A cylindrical sheet 51, arranged around the biconical skirt 50, forms a stiffener and improves the resistance of the assembly. In addition to this resistance security, the sheet 51 constitutes good protection for the personnel3 serving against burns. It also makes it possible to have between it and the skirt 50 a heat-insulating material.

 Having described the device of the invention, we can now approach its operation.

 The exhaust gases to be treated, such as those of an internal combustion or internal combustion engine, enter via the pipe 19, pass through the annular chamber 22, where they already begin to be centrifuged, the cooling fin tubes 25, 26, where their temperature is lowered, the inlet cone 8, the expansion chamber of the skirt 4, the separation baffles 6 where they are divided and centrifuged and rid of their carbonic particles in ignition, and the outlet chamber 24 , and exit through the tube 20. The carbon dioxide particles separated in the stack of baffles 6 flow through the inlet cone 8 onto the retaining cone 16 before being collected in the receptacle 15, whence we can evacuate them, after opening the hatch 72. As for the carbon dioxide particles already separated in the enclosure 17, they are also collected in the receptacle 15, by means of the frustoconical surface 14 serving as a retaining surface .

 The enclosure 17, with its cooling water, constitutes a good anti-vibration partition which absorbs the noise generated inside the body 1.

 In addition, the body 1 of the stack of separation baffles 6 is also cooled, which makes it possible to further extend the lowering of the temperature of the gases during their passage through the baffles, and to avoid any ignition of the air. oxidizer outside.

 It will be noted, with reference to FIGS. 2 and 3, that directional vanes 60 have been provided in the inlet chamber 22, arranged substantially vertically but curved and inclined downward, in line with the cooling tubes 25, 26, in order to direct the flow of gases entering the cooling tubes and thus avoid turbulence or backpressure. A system for cleaning the cooling tubes has also been provided to remove carbon dioxide particles which foul them. In the form shown in FIG. 1, this system comprises a pipe 70 for injecting compressed air, opening into the inlet chamber 22, at the level of the conical partition 21, and a beating flap 71, mounted in the pipe 19 for entering the gases, which comes to bear on a seat, during the injection of compressed air, so that it is not returned to the engine to which the entire device is connected. The cleaning is carried out after opening the devatting hatch 72 of the receptacle 15.

 Instead of this cleaning system, one could also provide, by tube, a brush, or doctor blade, descaling mounted movable in translation and in rotation inside the associated tube, and maneuverable from the outside - of the device spark arrester exchanger, for example using a pivotally mounted lever.

Claims (10)

Claims  1.- Spark arrester comprising a body, provided with inlet and outlet ports for exhaust gas from a rotary explosion or internal combustion machine and known means arranged in the body for separating carbon particles exhaust gases, characterized in that there is provided, around said body, an envelope forming with said body an annular enclosure provided with inlet and outlet openings and communicating, through its outlet opening, with the inlet orifice of said body, and cooling means arranged in the enclosure for cooling the exhaust gases passing through the enclosure from its inlet opening to its outlet opening.  2. A spark arrester according to claim 1, in which said means for separating carbon dioxide particles comprise a stack of baffles.  3. A spark arrester according to claim 2, wherein said baffles each have two vents in the shape of a half-cone.  4. Spark arrester according to one of claims 1 to 3, wherein said cooling means comprise finned tubes immersed in a circulating cooling fluid.  5. A spark arrester according to claim 4, in which the respective fins of two adjacent cooling tubes are interposed with one another.  6. A spark arrester according to one of claims 4 and 5, in which directional vanes are provided for directing the exhaust gases into the cooling tubes.  7. A spark arrester according to one of claims 4 to 6, in which are provided means for descaling the cooling tubes.  8. A spark arrester according to claim 7, in which the said descaling means comprise a tube for injecting compressed air, and a flap is provided in the inlet opening of the annular enclosure.  9. A spark arrester according to one of claims 1 to 8, in which said enclosure comprises an inlet chamber with a frustoconical partition.  10. A spark arrester according to one of claims 1 to 9, in which is arranged, around the envelope of the annular enclosure, a biconical skirt forming a venturi.