the applicant company has now found that it is possible to reduce , or even to eliminate , the abovementioned drawbacks by modifying the design of said injector . the subject of the present invention is therefore an injector in as depicted schematically in fig5 that can be used in particular in a device for the combustion of corrosive products or product mixtures or those likely to generate corrosive products by bringing said products ( in the dispersed state ) into contact with an oxidizer at a temperature that allows said products to burn , characterized in that it comprises a straight cylindrical wrapper tube ( e ), closed at one end by a wall ( p ), inside which tube are juxtaposed at least 2 straight tubes ( t ) and at most 8 tubes , preferably 4 or 5 tubes , said tubes passing at right angles through the wall ( p ), and at least one lateral nozzle ( tl ) situated near the wall ( p ). according to the present invention , these tubes ( t ) may have identical or different inside diameters . these tubes ( t ) may be arranged randomly but it is preferable for them to be arranged in a ring . fig6 depicts a section through the injector on aa ′ of fig5 said injector containing 4 tubes of the same diameter arranged in a ring . fig6 depicts a section through an injector comprising 5 tubes : 4 tubes of the same diameter are arranged in a ring , and the 5th , of smaller diameter , is central . according to the present invention , at least one of the tubes ( t ) conveys corrosive products or product mixtures for burning and at least one of the tubes ( t ) conveys all or some of the oxidizer needed for the combustion . this oxidizer may be air , oxygen - enriched air or , alternatively , oxygen . depending on the calorific value of the products that are to be burned , a top - up fuel such as propane , vent gases from the manufacture of pvc , fuel , etc . may be supplied . this top - up fuel , according to the present invention , may be conveyed by one of the tubes ( t ) of the device . the space created by the juxtaposed tubes ( t ) inside the wrapper tube ( e )— which space is denoted by ( et )— may be swept by a fluid for cooling the tubes ( t ) or alternatively may bring in top - up oxidizer for combustion . this fluid is preferably air , humidified air , water , steam and is introduced , preferably tangentially , to the wrapper tube ( e ) and preferably at its lower part via a nozzle ( tl ). the thicknesses of the tubes ( t ) and of the tube ( e ) may vary to a large extent . they are dependent on the material used and on the corrosiveness of the products that are to be destroyed . advantageously , these thicknesses will be at least equal to 1 . 5 mm and preferably between 1 . 5 and 3 mm . according to one embodiment of the injector in according to the invention , it is recommended that the various tubes ( t ) be dimensioned in such a way that the ratio of the outside diameter de of a tube ( t ) to the inside diameter di of the same tube ( t ) is between 1 . 2 and 1 . 6 and preferably between 1 . 25 and 1 . 5 . furthermore , according to the present invention , the ratio of the total internal surface area of the tubes ( t ), σs t , to the internal passage cross - sectional area of the tube ( e ), s et , containing n tubes ( t ) is between 1 and 1 . 50 and preferably between 1 . 05 and 1 . 25 . the length of the tube ( e ) is 20 to 30 times the inside diameter of said tube ( e ), and preferably 22 to 26 times this diameter . it is the task of the person skilled in the art to select the precise ratios , within the limits recommended above , according in particular to the flow rates chosen for the corrosive products that are to be destroyed and the various other fluids . the tubes are supplied upstream of the wall ( p ) by hoses which are fitted with “ quick - fit ” connectors ( j ) of the surlock ® type , allowing them to be fitted and removed quickly . upstream of the wall ( p ), the tubes ( t ) may adopt a curvature so as to make them easier to connect to the supply hoses . their lengths , still upstream of the wall ( p ) may be identical or different and depend on the size of the device . the ends of the tubes ( t ) are at the same level ( in the same plane ) as the end of the tube ( e ) ( line bb ′ in fig5 ). according to the present invention , the injector in of the present invention can be arranged vertically or horizontally . another subject of the present invention also relates to the use of said injector described hereinabove for implementing a method for the combustion of corrosive products or corrosive product mixtures likely to generate corrosive products . according to this method , the phase ( s ) containing the products to be burned is ( are ) introduced in liquid and / or gaseous form along the axis of the vortex sink formed by the primary fraction of the oxidizing phase practically as far as the depression region of said vortex sink , the momentum conferred upon the vortex sink being enough to cause the phase to be burned to be dispersed into particles through the transfer of momentum and the secondary fraction of the oxidizing phase is introduced separately at a flow rate and in one or more directions making it possible , simultaneously , to provide the complement of oxidizing phase needed for combustion , to cool the part of the device surrounding the combustion zone and , in particular , the deflector allowing the secondary fraction to be deflected toward the base of the combustion zone and to stabilize the incandescent cloud . the products to be burned are introduced preferably in liquid form at a flow rate ranging from 500 to 3500 kg / h and preferably between 1200 and 3000 kg / h . when introduced in gaseous form , their flow rate is between 5 and 15 sm 3 / h . the flow rate of the primary fraction of the oxidizing phase ( also known as the atomization air ) is between 500 and 5000 sm 3 / h and preferably between 2000 and 3500 sm 3 / h . in the implementation of the method according to the invention , the combustion zone is at a depression of the order of 10 to 1500 pa below atmospheric pressure . the pressure of the primary fraction of the oxidizing phase is 0 . 1 to 8 . 5 × 10 5 pa higher and preferably 0 . 2 to 0 . 6 × 10 5 pa higher than the pressure in the combustion zone . the secondary fraction of the oxidizing phase may be introduced into the combustion chamber by induction at various points given the depression in the combustion chamber . this secondary fraction may be introduced in a single flow , particularly deflected toward the combustion zone by means of a deflector as mentioned hereinabove , or in the form of two flows flowing one on each side of said reflector . the total flow rate of the secondary fraction of the oxidizing phase can vary to a large extent . in general , this flow rate is calculated in such a way that the ratio of the total flow rate of the secondary fraction to the flow rate of the primary fraction is between 0 . 1 and 10 and preferably between 0 . 9 and 5 . given the nature of the products to be burned , it is possible to supply a top - up fuel in liquid or gaseous form , and it is advantageous that this fuel be introduced through one of the tubes of the injector according to the invention . according to the present invention , water may also be introduced into the combustion zone . this introduction is also advantageously achieved through one of the tubes of the injector according to the invention . a top - up of oxidizing phase known as tertiary phase may be used . if it is , this top - up is made coaxially using a nozzle arranged at right angles to the wrapper tube of the injector . this top - up is introduced at a pressure ranging from 2 bar to 10 bar and preferably at a pressure ranging from 4 to 6 bar . the use of the injector of the present invention , aside from yielding remarkable combustion of the corrosive products , equivalent to that achieved by burners of the prior art , has the advantage that said corrosive products can be combusted over several months without there being any blockage and / or holing of one ( or more ) tube ( s ) of which said device is made . in the event that a blockage occurs in one or more tubes , there are several simple and quick options : the use of a simple flexible wand introduced into the tube may allow the blockage to be removed without shutting the burner down ( the furnace is at a depression ), or alternatively , if the blockage is more sizeable , the entire device can be changed quickly , in under one hour , without an appreciable reduction in furnace temperature . the injector of the present invention makes it possible to combust corrosive products or product mixtures under remarkable conditions . this injector applies quite particularly to the combustion of chlorinated liquid residues which are generally viscous , possibly laden with solid particles in suspension . these chlorinated residues as defined earlier often contain more than 40 %, or even more than 75 % by weight of chlorine . however , it is clearly understood that the device of the present invention can be used for the combustion of corrosive products , or those likely to yield corrosive products , containing quantities of chlorine well below 40 %. the injector according to the invention also makes it possible to burn , at the same time as the liquid chlorinated residues , gaseous chlorinated residues such as , in particular , the vent gases originating from the manufacture of polyvinyl chloride . another advantage is the possibility of quickly changing over the supply to a tube , given the connections ( j ). the tubes ( t ) can also be cooled by causing air , water or humidified air to pass through the space ( et ). given the fact that the injector of the present invention can operate for several months without blockage , better stability in the operation of the furnace , in the combustion , and improved safety are observed . the vent gases are also found to have a constant quality . injector according to the invention as depicted in fig5 and 6 . number of tubes ( t ): 4 : ( t 1 ), ( t 2 ), ( t 3 ), ( t 4 ). the inside ( di ) and outside ( de ) diameters of the 4 tubes are identical . total external surface area of the 4 tubes : 346 . 36 × 4 = 1385 mm 2 length of tubes ( t ): 1 . 45 m ( including the part upstream of the wall ( p )) inside diameter : 51 mm , namely an internal surface area of 2043 mm 2 cross - sectional area of the passage s et between the wrapper tube ( e ) and the tubes ( t ): 2043 − 1385 = 658 mm 2 the tubes t 1 , t 2 , t 3 and t 4 are arranged as indicated in fig5 . this injector is designed for an installation for the combustion of residues as described previously in the description , that is to say that the injector in of the present invention is arranged in place of the injector ( 8 ). in the dispersion head depicted in figure ( 4 ), and penetrates said dispersion head over a length of 48 cm ( cc ′) measured from the guide ( 9 ), namely 72 cm outside of said head ( dd ′) the chlorinated residues to be destroyed consist on the one hand of pcbs and , on the other hand , of chlorinated residues containing approximately 80 % by weight of chlorine and consist essentially of hexachlorobutadiene , hexachlorobenzene , tetrachlorobenzene and aliphatic chlorinated products such as hexachloroethane . the pcbs are introduced via the tube ( t 1 ) at a flow rate of 400 kg / h . the chlorinated residues are introduced by the tube ( t 2 ) at a flow rate of 1600 kg / h . the gaseous chlorinated vent gases originating from the preparation of pvc are introduced via the tube ( t 3 ) at a flow rate of 10 m 3 / h . water is introduced through the tube ( t 4 ) at a flow rate of 500 kg / h . tertiary air is introduced into the wrapper ( e ) by means of the nozzle ( tl ) at a flow rate of 10 m 3 / h . 2700 sm 3 / h of primary ( or atomization ) air is introduced at a pressure of about 0 . 5 × 10 5 pa into the annular space ( 27 / 26 ) via the tangential inlet ( 15 ). an overall flow rate of secondary air of about 2500 sm 3 / h is made up of a first flow of secondary air drawn in through the holes ( 21 ) in the bottom plate ( 19 ) and a second flow of secondary air drawn in through the annular leakage space ( 23 ). the ratio ( 27 )/( 26 ) is 1 . 28 and the ratio ( 28 )/( 27 ) is 4 . furthermore , the head of the injector in is 6 . 8 cm from the plane formed by the ends of the deflector ( 24 ). the device for the combustion of these residues ran for 6 months without any blockages being observed in the injector of the invention . by contrast , when operating with an injector of the prior art as depicted schematically in fig2 blockages are observed after 30 days of operation . the mean composition of the flue gases leaving the combustion chamber is as follows ( percentages by weight ): after these flue gases are treated as mentioned previously in the description , there is obtained a clear solution containing about 30 wt % of hcl . the flue gases discharged into the atmosphere contain no free chlorine . analyses performed on the flue gases show that the pcb content is below 0 . 5 μg / sm 3 ; the content of polychorodibenzofuran and polychlorodibenzodioxin in the gases is 0 . 1 ng / m 3 .