Silencer and Open-Structured Catalyser

Abstract

The invention relates to an apparatus arranged within a gas flow system, said apparatus comprising a matrix structure composed of a plurality of solid elements being arranged singularly or in groups. The gas flow system comprises a plurality of voids in-between said solid elements. The matrix structure allows gas to propagate within said matrix structure, and the matrix structure is intended for changing the chemical composition of said gas having passed through the system. The change in chemical composition either takes place during one or more of the following processes: one or more chemical reactions promoted by catalytic coating of said elements, promoted mixing of different phases of components of said gas, or phase change by fluid drops evaporating or solid particles changing phase, or takes place by the matrix structure having a degree of open structure of said matrix structure for allowing the gas to flow along an overall flow pattern being a not-truly 3-dimensional flow pattern.

1 - 101 . (canceled)  
   
   
       102 . An apparatus arranged within a gas flow system comprising at least one matrix structure composed of a plurality of solid elements being arranged singularly or in groups, and said gas flow system comprising a plurality of voids in-between said solid elements, 
 a majority of said singular solid elements or said groups of said solid elements being mechanically interconnected to a coherent mechanical structure including said voids,    said matrix structure allowing gas to propagate within said matrix structure essentially along streamlines extending in any direction in space, directly or by circumventing said solid elements, thereby allowing for flow resistance to be significantly greater in one or more directions than in one or more other directions,    said matrix structure being adapted to perform, solely by said matrix structure or in conjunction with other parts of said gas flow system, a change in the chemical composition of said gas having passed through the said system, due to one or more of the following processes taking place adjacent to the surfaces of said elements of said matrix structure: one or more chemical reactions promoted by catalytic coating of said elements, promoted mixing of different phases of components of said gas, or phase change by fluid drops evaporating or solid particles changing phase    wherein the mechanical interconnection of said singular solid elements or said groups of said solid elements into the coherent mechanical structure including said voids is provided by at least one of the following mechanical structures:    elongated mechanical members such as threads, strips or fibres having been arranged together by welding, brazing, soldering, fusing, weaving, spinning, intertwining or the like processes to create the voids, or    one or more solid pieces of material having been work-processed such as having been processed by cutting, grinding, stamping, bending, stretching or etching out or the like work processes to create the voids, and    wherein the said gas flow system additionally comprises at least one honeycomb structure in which gas flows predominantly inside longitudinal, essentially parallel flow channels, and wherein walls of the honeycomb structure are essentially impervious, said channels being open at both ends, and    wherein at least one said matrix structure has been arranged upstream and/or downstream of said honeycomb structure and has been designed by adapting the flow resistance generally or in a specific an-isotropic way and/or by variation of said catalytic coating of said matrix that compensation is made for any non-uniform flow distribution of flow among said passages or channels of the said at least one honeycomb.    
   
   
       103 . An apparatus according to  claim 102 , wherein said matrix structure has been organised in a regular, partly regular or random way regarding inner details of the said structure.  
   
   
       104 . An apparatus according  claim 102 , wherein said streamlines are defined for gas elements that are bigger than a characteristic dimension of said elements and said voids, such as the thickness of a thread of the structure or the width of a mask between fibres of the structure, such that the flow pattern is viewed at a level of coarseness that is more coarse than details in said matrix structure, optionally wherein the degree of open structure of the matrix structure is defined by a dimensional resolution of the matrix structure that is significantly coarser than a characteristic dimension of said elements and said voids, such as the thickness of a thread of the structure or the width of a mask between fibres of the structure.  
   
   
       105 . An apparatus according to  claim 102 , wherein said gas when being allowed to flow through said matrix structure results in at least one of the following processes: contact between gas flowing through the said matrix structure to cause mixing of separate components or phases within the gas, phase change, one or more catalytic reactions promoted by catalytic material having been applied to a surface of the matrix structure, retaining of solid particles from the gas.  
   
   
       106 . An apparatus or a silencer according to  claim 102 , wherein the said matrix structure is constituted by at least one plane or curved grid or net with elongated elements such as threads or flat strips.  
   
   
       107 . An apparatus or a silencer according to  claim 102 , wherein the said matrix structure is constituted by at least one plane or curved perforated plate.  
   
   
       108 . An apparatus or a silencer according to  claim 102 , wherein the said matrix structure is composed of at least two groups of said matrix structures that are arranged adjacent or in-between each other, the first said group being of a significantly coarser structure than the second said group, the first said group providing significant mechanical strength of the said matrix, and the second said group adding an amount of mechanical surface per unit volume of the said matrix, thereby intensifying any process referred to in previous claims, one or more said groups carrying the same or differing types of catalytic coating, either to fit in much catalytic surface within a given space, or using differing catalytic coatings on elements of the differing groups in order to promote concurrent chemical reactions.  
   
   
       109 . An apparatus or silencer according to  claim 106 , wherein said honeycomb structure is at least partly catalytically coated and is having passages or channels that are open at both ends, and wherein said honeycomb structure comprises a plurality of elongated members extending inside the said passages or channels of the said honeycomb structure, at least part of said elongated members being catalytically coated.  
   
   
       110 . An apparatus or a silencer according to  claim 102 , wherein elongated members form part of or are attached to said matrix structure, and wherein the elongated members extend into said passages or channels of a said honeycomb structure, and wherein the elongated members are catalytically coated.  
   
   
       111 . An apparatus or a silencer according to  claim 106 , wherein said elongated members have been formed to a shape that deviates from a substantially straight shape, such as to comprise one or more curvatures within substantially a plane, or in sections of planes that may be tilted individually or may be aligned with each other, or to constitute a true 3-dimensional shape.  
   
   
       112 . An apparatus or a silencer according to  claim 111 , wherein the said elongated members or threads are shaped partly or wholly as a helical screw whose diameter can be changed elastically by applying torsion onto the said elongated members or threads.  
   
   
       113 . An apparatus or a silencer according to  claim 106 , wherein one or more of said honeycombs and said elongated members or treads have been catalytically coated either with essentially the same coating or by different coatings.  
   
   
       114 . An apparatus or a silencer according to  claim 106 , wherein said elongated members or said threads occupy at the most 50% of the cross-sectional area inside a said passage or channel, or at the most 25% of said cross-sectional area, or at the most 10% of the said cross-sectional area.  
   
   
       115 . An apparatus or a silencer according to  claim 106 , wherein individual elongated members or threads extends inside said passages or channels of a said honeycomb structure, and wherein said individual elongated members or said threads are of different lengths.  
   
   
       116 . An apparatus or a silencer according to  claim 106 , wherein individual elongated members or threads extends inside said passages or channels of a said honeycomb structure, and wherein said individual elongated members or said threads have different cross-sectional areas.  
   
   
       117 . An apparatus or a silencer according to  claim 102 , wherein said matrix structure is a catalyser being such arranged inside the said apparatus or silencer that an overall mean direction of flow direction can be singled out, the said catalyser comprising an inlet section to the said matrix structure, within which inlet section flow resistance in directions substantially perpendicular to the said mean direction of flow is significantly smaller than flow resistance in the direction of said mean flow direction.  
   
   
       118 . An apparatus or a silencer according to  claim 102 , wherein said at least one matrix structure has been arranged inside a chamber provided with at least one inlet passage and at least one outlet passage for gas to pass through the said chamber, the flow of gas, when passing said chamber, changing its direction by at least 45 degrees, the overall direction of flow passing through said at least one matrix structure also changing its overall flow direction by at least 45 degrees, and wherein said matrix structure is a catalyser.  
   
   
       119 . A silencer according to  claim 106 , wherein gas, when being led into a said chamber, is led via perforations of at least one inlet pipe extending forwards into said chamber, and where at least one said matrix structure surrounds said perforations in such a way that essentially all gas, when passing through said perforations of said inlet pipe, will also pass said matrix structure, and wherein said matrix structure is a catalyser.  
   
   
       120 . A silencer according to  claim 106 , wherein gas, when being led from a said chamber, passes through perforations of at least one outlet pipe extending backwards into the said chamber, and where at least one said matrix structure surrounds said perforations in such a way that essentially all gas, when passing through said perforations of said outlet pipe, will also pass said matrix structure, and wherein said matrix structure is a catalyser.  
   
   
       121 . A silencer according to  claim 106 , wherein gas, when being led into a said chamber, is led via an opening which is covered by said matrix structure being a catalyser, said opening being of such a shape and having such dimensions that essentially all gas, when entering said chamber, enters via said matrix structure by a gas flow pattern inside said matrix structure, said gas flow pattern generally diverging from said opening.  
   
   
       122 . A silencer according to  claim 106 , wherein gas, when being led from a chamber, is led via an opening which is covered by said matrix structure being a catalyser, said opening being of such a shape and having such dimensions that essentially all gas, when leaving said chamber, leaves via the said matrix structure by a gas flow pattern inside said matrix structure, said gas flow pattern generally converges towards said opening.  
   
   
       123 . An apparatus or a silencer according to  claim 102 , wherein said matrix structure is a catalyser and is placed in front of at least one opening for leading gas to a chamber in a predominant mean direction, said matrix structure being either circular of a diameter D or having another cross-sectional shape with a largest dimension D taken in a direction transverse to said predominant mean direction, a distance between said at least one opening and said matrix structure being less than two times said dimension D.  
   
   
       124 . An apparatus or a silencer according to  claim 123 , wherein said distance between said at least one opening and said matrix structure is less than the said dimension D.  
   
   
       125 . A silencer according to  claim 106 , wherein said matrix structure is arranged within a passage in such a way that gas flow, when passing through said passage, will also pass said matrix structure.  
   
   
       126 . A silencer according to  claim 106 , wherein said matrix structure is arranged inside a passage in such a way that a majority of cross-sections of said passage is only partly filled out by the said matrix structure.  
   
   
       127 . A silencer according to  claim 106 , wherein said matrix structure is arranged inside a passage in such a way that all cross-sections of said passage is only partly filled out by the said matrix structure.  
   
   
       128 . A silencer or an apparatus according to  claim 102 , wherein the flow pattern upstream of a said matrix structure generally rotates around an axis of said matrix structure.  
   
   
       129 . A silencer according to  claim 106 , wherein the flow pattern downstream of said matrix structure generally rotates around an axis of said matrix structure.  
   
   
       130 . A silencer according to  claim 106 , wherein at least one curved passage extends helically and essentially surrounds at least one said matrix structure.  
   
   
       131 . A silencer according to  claim 106 , wherein at least one curved passage extends helically and essentially surrounds at least one said honeycomb structure.  
   
   
       132 . A silencer according to  claim 106 , said silencer comprising at least a first and a second acoustic chamber being at least partly filled out by at least one said matrix structure, and wherein the first said chamber essentially surrounds the second said chamber.  
   
   
       133 . A silencer according to  claim 106 , said silencer comprising at least a first and a second acoustic chamber being at least partly filled out by at least one said honeycomb structure, and wherein the first said chamber essentially surrounds the second said chamber.  
   
   
       134 . A silencer according to  claim 106 , wherein said matrix structure is of an annular shape.  
   
   
       135 . A silencer according to  claim 132 , wherein said matrix structure is arranged inside the said first chamber, and wherein said first chamber is of an annular shape.  
   
   
       136 . A silencer according to  claim 102 , wherein two chambers are interconnected by an interconnecting member in which interconnecting member gas flow elements will pass from the one said chamber to the other said chamber along various flow lines, each said flow line being substantially longer than if said flow were to pass in an essentially rectilinear flow from the first said chamber to the second said chamber.  
   
   
       137 . A silencer according to  claim 136 , wherein said interconnecting member is capable of leading gas flow from said one chamber to said other chamber via at least one spirally or helically extending passage inside said interconnecting member.  
   
   
       138 . A silencer according to  claim 106 , wherein one or more of said matrix structures occupy an amount of space inside a chamber, said amount, apart from any space occupied by possible sound-absorptive material arranged inside said chamber, amounts to less than 10%, or between 10% and 30%, or between 30% and 50%, or between 50% and 70%, or between 70% and 90%, or more than 90% of the total space of a chamber of the said silencer.  
   
   
       139 . A silencer according to  claim 106 , wherein at least one said matrix structure occupies an amount of space inside a shell of the silencer, said amount, apart from any space occupied by possible sound-absorptive material and by possible thermal insulation material and by possible inner mechanical design members of said silencer, amounts to less than 10%, or between 10% and 30%, or between 30% and 50%, or between 50% and 70%, or between 70% and 90%, or more than 90% of the total space within said shell of said silencer.  
   
   
       140 . Use of a matrix structure for an apparatus or a silencer according to  claim 102 , wherein the matrix structure has an open structure in a degree that flow of gas can pass within said matrix structure essentially along streamlines extending in any direction in space, and wherein said matrix structure during use performs chemical conversion of gas, including optional retaining of suspended particles, flowing through the apparatus or the silencer.  
   
   
       141 . Use according to  claim 140  of a matrix structure for an apparatus or a silencer, wherein the apparatus or the silencer also comprises at least one said honeycomb structure or foiled structure, and wherein said honeycomb structure or foiled structure also performs chemical conversion of gas, including optional retaining of suspended particles, flowing through the apparatus or the silencer.  
   
   
       142 . A combination of a honeycomb catalyser and a plurality of elongated members, said catalyser having essentially impervious walls surrounding channels that are open at both ends, said elongated members extending inside said channels and being catalytically coated.  
   
   
       143 . A method of optimising an apparatus or a silencer or one or more matrix structures according to  claim 102  comprising one or more steps of computerised modelling a said apparatus or silencer or one or more matrix structures where one or more virtual matrix structures, representing a future, real matrix structure(s) of the same outer shape as the virtual structure(s), is/are incorporated, said virtual matrix structure(s) being defined by mathematical functions that are initially not necessarily being related to specific shapes or dimensions of the one or more matrices, but represent desired characteristics of the one or more virtual matrix structure(s), said virtual matrix structure(s) later to be replaced by physical matrix structure(s), either in computerised modelling based on known characteristics as they can be ascertained from a physical specification, or in a physical experiment, designing said physical matrix structure(s) such that their characteristics will crudely, as far as possible or rather closely match those of the virtual matrix structure(s).  
   
   
       144 . A method according to  claim 143 , wherein one or more of the following types of mathematical functions are defined: 
 vector v*(x,y,z) of dimension m/s    vector λ*(x, y, z) being dimensionless    scalar c(x, y, z) of dimension: m 2 /m 3 =m −1      one or more scalars m′(x,y,z), m″(x,y,z), . . .    and one or more scalars r′(x, y, z), r″(x,y,z), . . .    said vector v* representing the flow velocity at a given point x,y,z,    said vector λ* representing an isotropic or an-isotropic length specific flow resistance in analogy with the dimensionless number λ=Δp/((L/d)0.5ρv 2 ) representing the length specific flow resistance of pipe, flow propagating along the pipe,    said scalar c representing the amount of reactive (sometimes catalytic) surface per unit volume,    said one or more scalars m′, m″, . . . representing molar concentrations of one or more chemical constituents,    and said one or more scalars r′, r″, . . . representing time rates of chemical reactions that will in general depend on concentrations, flow velocities, specific flow resistance, and possibly further space-varying variables, such as for instance temperature, such further variables to be defined in analogy with the variables that have been specified by way of example.