Aerosol Generator, In Particular Soot Generator

Abstract

An aerosol generator, in particular a soot generator. The aerosol generator includes a combustion chamber, in which fuel can be burned with an oxidizing agent in at least one soot-particle-creating flame, and a fluid feeding device for feeding fuel and an oxidizing agent into the combustion chamber. The fluid feeding device has at least three feed lines, the outlet-side end portions of which run parallel, so that at least three fluids of different types, in particular gases, can be introduced into the combustion chamber unmixed and in a parallel inflow direction.

Claims

1. An aerosol generator, configured as a soot generator, comprising a combustion chamber, in which fuel can be burned with an oxidizing agent in at least one soot-particle-creating flame; a fluid feeding device for feeding the fuel and the oxidizing agent into the combustion chamber; wherein the fluid feeding device has at least three feed lines each feed line having a respective end portion, the respective end portions of each feed line are arranged parallel to each other so that at least three fluids of different types can be introduced into the combustion chamber unmixed and in a parallel inflow direction.

2. The aerosol generator according to claim 1, wherein the respective end portions of the at least three feed lines are arranged coaxially in one another.

3. The aerosol generator according to claim 1, wherein at least one of the respective end portions are arranged lying parallel next to one another; and the respective end portions are arranged parallel next to one another to form an arrangement of lines with a packing density that is as great as possible.

4. The aerosol generator according to claim 1, wherein the fluid feeding device has one of: at least four feed lines; four feed lines; and seven feed lines.

5. The aerosol generator according to claim 1, wherein respective outlets of the feed lines are located at a same height with respect to an inflow direction.

6. The aerosol generator according to claim 1, wherein a first of the feed lines is connected on an inlet side to a first fluid container containing a first fuel; and a second of the feed lines is connected on an inlet side to a second fluid container, containing a second fuel.

7. The aerosol generator according to claim 4, wherein a third of the feed lines is connected on an inlet side to a third fluid container, containing an oxidizing gas; and a fourth feed line is connected on an inlet side to a fourth fluid container, containing one of a reactive gas and an inert gas.

8. The aerosol generator according to claim 1, wherein a fluid flow rate can be set in each of the respective feed lines by a regulator.

9. The aerosol generator according to claim 1, wherein the respective end portions of each feed line are arranged parallel to each other so that respective fluids are introduced into the combustion chamber unmixed and in a same inflow direction.

10. The aerosol generator according to claim 9, wherein each feed line is parallel to a longitudinal axis of the combustion chamber.

11. The aerosol generator according to claim 10, wherein each respective end portion of each feed line is arranged in the combustion chamber at a same fixed height from a base of the combustion chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The preferred embodiments and features of the invention that are described above can be combined with one another as desired. Further details and advantages of the invention are described below with reference to the accompanying drawings, in which:

[0027] FIG. 1 is a schematic representation of a soot generator;

[0028] FIGS. 2A and 2B are sectional views of an outlet-side end portion of the fluid feeding device; and

[0029] FIG. 3 is a sectional view of an outlet-side end portion of the fluid feeding device.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0030] Elements that are the same or functionally equivalent are denoted by the same designations in all of the figures.

[0031] FIG. 1 schematically shows a cross section of an exemplary embodiment of the soot generator 1 according to the invention.

[0032] The soot generator represented in FIG. 1 comprises a combustion chamber 7, in which at least one fuel with an oxidizing agent can be burned in at least one soot-particle-creating flame 10. The combustion chamber 7 may be embodied in a way known per se and be formed for example by a cylindrical outer tube 6, at the lower end of which an end portion of a fluid feeding device 2 protrudes into the combustion chamber 7.

[0033] The fluid feeding device 2 can be used for introducing combustible gases, an oxidizing gas and possibly further gases, such as a reactive gas or an inert gas, into the combustion chamber.

[0034] In the example shown, the fluid feeding device 2 has four feed lines 3.1, 3.2, 3.3 and 3.4. However, it is emphasized that the fluid feeding device may also have a greater number n of feed lines.

[0035] The outlet-side end portions 4.1, 4.2, 4.3 and 4.4 of the feed lines 3.1, 3.2, 3.3 and 3.4 run parallel, the outlets 9 of the feed lines being located at a same height with respect to the inflow direction R. In this way, in the exemplary embodiment shown four gases of different types can be introduced into the combustion chamber 7 separately and in a parallel inflow direction. The inflow direction of the gases emerging from the outlets 9 of the feed lines is indicated by the arrow identified by the designation R.

[0036] The end portions 4.1, 4.2, 4.3 and 4.4 of the feed lines 3.1, 3.2, 3.3 and 3.4 are arranged nested coaxially in one another, which is represented in FIG. 1 by the dashed lines. The feed line 3.4 for example goes over into a cylindrical inner tube portion 4.4, which runs coaxially and inside the tube portion 4.3 of the feed line 3.3. The feed line 3.2 goes into a tube portion 4.2, inside which there runs the tube portion 4.3. The feed line 3.1 goes into an outer tube portion 4.1, inside which there runs the tube portion 4.2.

[0037] Such an arrangement of the respective end portions of the feed lines nested coaxially in one another is illustrated once again in FIGS. 2A and 2B, but for an exemplary embodiment with three feed lines. FIG. 2A shows here a plan view of the outlets 9 of the end portions 4.1, 4.2 and 4.3, while FIG. 2B shows a sectional view along the direction of flow.

[0038] The inlet 13 of one of the feed lines is connected to a fluid container (not represented), in which an oxidizing agent is stored, so that an oxidizing agent stored therein can be conducted with a certain inflow rate through the outlet 9 of the corresponding end portion into the combustion chamber 7. Respective inflow rates can be set by way of a valve 5.

[0039] Correspondingly, the inlets 13 of two more of the feed lines are respectively connected to different fuel containers, different combustible gases being stored in the fuel containers. In this way, two different combustible gases can be conducted into the combustion chamber 7. The inflow rate in each feed line can in turn be set by way of a valve 5.

[0040] The inlet of the fourth feed line can be connected or is connected to a fluid container (not represented), in which a reactive gas or an inert gas is stored, so that a reactive gas or an inert gas can be conducted with a certain inflow rate through the outlet 9 of the corresponding end portion into the combustion chamber 7. The inflow rate can in turn be set by way of a valve 5.

[0041] The fluid or fuel containers may for example be in each case a gas bottle, in which a gas is stored under positive pressure. For regulating the inflow rate, the valves 5 may be embodied as reducing valves.

[0042] After ignition, a flame 10, in which soot particles are formed as a result of combustion of the fuel with the oxidizing gas, forms over the outlets 9 of the feed lines 3.1 to 3.4.

[0043] By setting the inflow rates by way of the valves 5, the mixing ratio of the gases fed in can be varied, and consequently a direct influence can be exerted on the morphology (size and nature) of the particles generated and also on the chemical composition of the particles. Consequently, factors that influence the combustion, and with it the particle formation, can be varied independently of one another. If one of the combustible gases fed in is acetylene, then, for example, increasing the acetylene component in the combustible gas mixture leads to a greater carbon component in the combustible gas, and consequently to a greater formation of soot in the flame. If one of the combustible gases fed in is hydrogen, then increasing the hydrogen component leads to a greater carbon content in the particles formed. The use of pure hydrogen leads to a flame that is free from soot. In this case, the emission of particles may be caused for example by other reactive or inert gas components, for example sulphur-containing particles due to the use of S0.sub.2 and/or H.sub.2S.

[0044] The upper end 8 of the combustion chamber may be embodied in a way known per se. For example, an aerosol or soot discharging line (not represented) may be provided, with a mouth opening into the combustion chamber, through which soot particles and/or aerosols formed in the combustion chamber can be discharged.

[0045] FIG. 3 illustrates a further variant of an embodiment of the feeding device, a plan view of the outlets 9 of the end portion of the feeding device that opens out into the combustion chamber being shown. As can be seen in FIG. 3, a special feature of this variant of the embodiment is that the feeding device has seven separate feed lines, the end portions of which are arranged parallel next to one another to form an arrangement of lines 12 with a packing density that is as great as possible. For this purpose, the end portions are arranged parallel next to one another, one of the end portions being arranged in the middle, while the six remaining end portions are arranged uniformly distributed around the circumference and at as little distance as possible from the end portion that is arranged in the middle.

[0046] Possible applications for the particles or the aerosols are for validating and/or calibrating particle measuring devices and particle sensors and also for testing and assessing filters and catalysts. By introducing appropriate chemical components, the aerosol generated can also be used for the ageing of sensors, catalysts and filters. The use of the aerosols for measuring reaction kinetics makes possible the development of descriptive and/or predictive simulation models Likewise, kinetic investigations of model aerosols can be taken as a basis for functional development for optimizing filter loading models and regeneration strategies.

[0047] Although the invention has been described with reference to specific exemplary embodiments, it is clear to a person skilled in the art that various modifications can be made and equivalents used as replacements without departing from the scope of the invention. Consequently, the invention is not intended to be restricted to the exemplary embodiments disclosed, but also to include all exemplary embodiments that fall within the scope of the appended claims. In particular, the invention also claims protection for the subject matter and the features of the subclaims independently of the claims referred to.

[0048] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.