WO2019148228A1

WO2019148228A1 - Condensation particle counter with saturator

Info

Publication number: WO2019148228A1
Application number: PCT/AT2019/060040
Authority: WO
Inventors: Martin Kupper; Martin Kraft; Alexander Bergmann
Original assignee: Avl List Gmbh
Priority date: 2018-01-31
Filing date: 2019-01-31
Publication date: 2019-08-08
Also published as: DE112019000599A5; AT520844A1; AT520844B1

Abstract

The invention relates to a condensation particle counter (1) comprising a main channel (12), through which a carrier gas (3) flows along a main flow path (4) during a measurement operation; a saturator (5) for enriching the carrier gas (3), in particular for saturating the carrier gas, with an operating fluid (2), wherein the saturator (5) comprises a saturation body (27) which can be soaked with the operating fluid (2) and is soaked during the measurement operation, and the saturation body (27) comprises at least one saturation channel (28) which follows the main flow path (4) for conducting and enriching the carrier gas (3); a nozzle device (6) which opens into a nozzle section (13) of the main channel (12) downstream of the saturator (5) along the main flow path (4) and which is connected to a measurement aerosol feed line (7) and is designed to introduce a particle-loaded measurement aerosol (8) into the enriched carrier gas (3); and a condensation region (9) which is arranged downstream of the nozzle device (6) along the main flow path (4) for oversaturating the mixture containing the carrier gas (3), the operating fluid (2), and the measurement aerosol (8).

Description

Condensation particle counter with saturator

The invention relates to a condensation particle counter comprising a main channel, which is flowed through in the measurement operation along a main flow path of a carrier gas, a saturator for enrichment, in particular for saturation, of the carrier gas with a fuel, wherein the saturator comprises a saturable with the operating saturated and saturated in the measuring operation saturation body , and wherein the saturation body at least one of the main flow path following

A saturation channel for conducting and enriching the carrier gas comprises a nozzle device opening along a main flow path to the saturator into a nozzle section of the main channel and connected to a meteraerosol feed line for introduction of a particle laden messaerosol into the enriched carrier gas, one positioned along the main flow path downstream of the nozzle device Condensation region for supersaturation of the mixture containing the carrier gas, the fuel and the metered aerosol, a measuring device arranged along the main flow path downstream of the condensation region for detecting the particles of the measuring aerosol enlarged by the condensed fuel, and a tempering arrangement for controlling the temperature of the carrier gas.

Condensation particle counters are known and published in various embodiments. In conventional condensation particle counters an aerosol stream is saturated with a vaporous fuel and subsequently in a

Condensation cooled so that the particles contained in the aerosol flow act as condensation nuclei, where the condensing fuel accumulates. As a result, the particles are enlarged and can be detected with higher accuracy by a measuring device, in particular counted. The exhaust gas of an internal combustion engine is often used as a metered aerosol, for example to measure the particle emissions of a motor vehicle. Exhaust gases from

Internal combustion engines contain in addition to the particles to be measured, however, other components such as steam, unburned

Hydrocarbons or sulfuric acid. These other ingredients can interfere with the measurement and even damage the condensation particle counter. Out For this reason, the measuring aerosol is conditioned in conventional condensation particle counters. In this conditioning, the messaerosol is dried, cooled and diluted, for example. However, it has been found in practice that the conditioning of the measurement aerosol impairs the accuracy of the measurement, because during conditioning a considerable part of the particles of the measuring aerosol is lost or filtered out of the measuring aerosol, this problem occurring in particular with nanoparticles.

To solve this problem, so-called high-temperature condensation particle counter or HT-CPCs are known. In this particular type of condensation particle counter, the temperature along the flow of the

Messaerosols on the relevant dew point temperatures in the exhaust

contained and contained in vaporous constituents. As a rule, the dew point temperature of sulfuric acid is chosen as the minimum temperature, which is approximately in the range of 150 ° C. This prevents substances such as water vapor or vaporous sulfuric acid from condensing in the area of the measuring device and impairing the measurement or damaging the measuring device.

However, in practice it has been found that HT-CPCs present other problems that do not allow stable operation. Surprisingly, conventional HT-CPCs already cause damage to the saturator after a short period of operation, which greatly reduces the accuracy of measurement and the service life of the HT-CPC.

The object of the invention is now to overcome the disadvantages of the prior art

overcome and create an improved condensation particle counter, especially with permanently increased accuracy.

The object of the invention is characterized by the features of the independent

Claims solved.

The measurement accuracy of the condensation particle counter can be improved in particular by using an improved saturator. Intensive studies have shown that the saturation of the saturator in high-temperature condensation particle counters is caused by undesirable reactions of the fuel. Conventional operating materials are usually long-chain esters, in particular dioctyl phthalates, which are supplied in liquid form and taken up or bound in vapor form in the aerosol stream or in the carrier gas by the heating of the saturator. However, these esters have proven in practice to be insufficiently thermostable.

For conventional low-temperature condensation particle counters are as

Fluids also known as hydrocarbons. At higher temperatures, however, these hydrocarbons react with the oxygen of the aerosol stream or carrier gas, adversely affecting the molecular structure of the feeds. Moreover, at higher temperatures, so-called "cracking" of the hydrocarbons of the operating material occurs. By-products of this reaction are subsequently deposited in the saturator, which can lead to a laying of the saturator.

The measuring accuracy of the condensation particle counter can be increased, in particular, by using an improved nozzle device for distributed admixing of the measuring aerosol into the carrier gas.

For the purposes of the present disclosure, conditioning means a treatment, in particular filtering, dilution and / or drying, of the meteraerosol stream.

In particular, the invention relates to a condensation particle counter comprising a main channel, which in measuring operation along a main flow path of a

Carrier gas is flowed through, a saturator for enrichment, in particular for

Saturation of the carrier gas with a fuel, wherein the saturator comprises a saturated with the fuel saturable and saturated in the measuring mode saturation body, and wherein the saturation body comprises at least one of the main flow path following saturation channel for passing and enrichment of the carrier gas, a along the Hauptströmungspfads after the saturator in a nozzle portion of the main channel opening nozzle device connected to a Messaerosolzuleitung and for introducing a particle-laden Messaerosols in the

enriched carrier gas is arranged, a arranged along the main flow path to the nozzle device condensation region for supersaturation of the mixture containing the carrier gas, the fuel and the Meßaerosol, along the main flow path to the condensation region arranged measuring device for detecting the enlarged by the condensed operating material or the fuel particles the Meßaerosols, and a tempering arrangement for controlling the temperature of the carrier gas.

Optionally, it is provided that the saturation body is at least partially, preferably completely formed of a porous alumina ceramic material.

In particular, the saturable body or the aluminum oxide ceramic material has a porosity which has a sufficient capillary action for the operating medium or the operating material. For example, a saturation body should have a

Diameter of about 2.5 cm completely wetted or soaked, for example, if it is about 1/5 deep in the fuel.

Optionally, it is envisaged that the aluminum oxide ceramic material consists of over 80% of a mixture of Al2O3 and S1O2.

If appropriate, it is envisaged that the aluminum oxide ceramic material contains 45-55% Al 2 O 3, wherein the percentages are information on mass fractions.

If appropriate, it is provided that the aluminum oxide ceramic material contains 38-45% S1O2.

Optionally, it is provided that the alumina ceramic material 51, 7% AI2O3 and 42% S1O2. If appropriate, it is provided that the aluminum oxide ceramic material in addition to Al2O3 and S1O2 also contains 3-5% K2O, in particular 4.1% K2O.

If appropriate, it is provided that the aluminum oxide ceramic material contains, in addition to Al 2 O 3, SiO 2 and K 2 O, further constituents such as Fe 2 O 3, PO 2, CaO, MgO and / or Na 2 O, in each case in the range of or below 1%.

If appropriate, it is provided that the aluminum oxide ceramic material has a density of 2-3, in particular of 2.7 g / cm ³ according to the hydrostatic method DIN VDE 0335/2.

Optionally, it is provided that the alumina ceramic material a

Water absorption of less than 0.1% in particular of 0% according to the hydrostatic method DIN VDE 0335/2.

Optionally, it is contemplated that the saturation body comprises a plurality of saturation channels extending side by side along the main flow path through the

Saturation bodies extend, wherein the arranged between the saturation channels saturation channel walls are soaked in the measuring operation with the fuel.

Optionally, it is contemplated that the saturation channel walls extend in honeycomb or raster shape along the main flow path through the saturation body, thereby forming a plurality of honeycomb or raster-shaped saturation channels.

Optionally, it is provided that the saturation body is arranged in a trough-shaped portion of a saturation space of the saturator, and that the

trough-shaped portion is at least partially filled with the fuel.

Optionally, it is provided that a fuel supply line in the

trough-shaped portion of the saturator opens, that the fuel supply line is connected to an operating fluid reservoir, and that the trough-shaped portion and the fuel reservoir are formed by the connection with the fuel supply line as communicating vessels or act.

Optionally, it is provided that a level control device is provided for controlling the level of the fuel in the operating fluid reservoir, and that the level control device is set up via the fuel supply line for controlling or controlling the fuel supply to the saturation body.

Optionally, it is provided that the saturation space along the

Flauptströmungspfads is tubular and in the upper region, above the trough-shaped portion comprises a pressure compensation opening.

If necessary, it is provided that the shape and / or the course of the

Saturation space in the saturator is adapted to the shape and / or the course of the saturation body or are.

Optionally, it is provided that the saturation channels in a normal plane of the Flauptströmungspfads more than 70%, preferably more than 80% of the

Take the cross-sectional area of the saturation body, wherein incomplete

Saturation channels are not taken into account at the edge of the saturation body.

Subsequently, the invention will be based on an exemplary, not

restrictive, embodiment further described, which is shown in the figures. Show in it

Figure 1 is a schematic sectional view of an embodiment of a

Condensation particle counter,

FIG. 2 shows a detailed section of the condensation particle counter from FIG. 1,

Figure 3 is a further schematic sectional view of a

Condensation particle counter, in particular the

Condensation particle counter from FIG. 1,

Figure 4 is a schematic oblique view of relevant components of a

Distributor nozzle, as for example in a Condensation particle counter according to at least one of the figures 1 -3 can be used, and

Figure 5 is a schematic oblique view of relevant components of a

Saturation body, such as in a

Condensation particle counter according to at least one of the figures 1 -3 can be used.

Unless otherwise indicated, the reference numerals of the figures correspond to the following components: condensation particle counter 1, fuel 2, carrier gas 3, main flow path 4, saturator 5, nozzle device 6, aerosol supply line 7, measuring aerosol 8, condensation region 9, measuring device 10, temperature control device 11, main channel 12, Nozzle section 13, end section (of the distributor nozzle) 15, distributor nozzle 16, wall (of the nozzle section) 17, inlet cross section 18, outlet opening 19,

Inlet channel 20, distribution channel 21, inlet opening 22, overflow opening 23, free end (the meteraerosol supply line) 24, free cross section (of the free end of the

Messaerosolzuleitung) 25, outlet section (the distributor nozzle) 26, saturation body 27, saturation channel 28, saturation channel wall 29, trough-shaped portion 30, saturation space 31, fuel supply line 32, fuel reservoir 33,

Level control device 34, pressure compensation opening 35.

1 shows a schematic sectional view of a possible embodiment of a condensation particle counter 1 or an arrangement of a

Condensation particle counter 1 with a fuel 2, a carrier gas 3 and / or a metered aerosol. 8

The condensation particle counter 1 flows through a carrier gas 3 during normal operation along a main flow path 4. The carrier gas 3 is a gas-free and oxygen-free gas or gas mixture.

In this case, the carrier gas 3 flows through a saturator 5, in which the carrier gas 3 is enriched or saturated with a fuel 2. In the present embodiment, a nozzle device 6 is arranged along the main-flow path 4 after the saturator 5. The nozzle device 6 comprises a Messaerosolzuleitung 7 to the supply line of the metered aerosol 8 into the enriched or saturated carrier gas 3. In an advantageous embodiment, the metered aerosol 8 is a

Unconditioned partial flow of the exhaust gas of a test specimen such. one

Internal combustion engine, an internal combustion engine with a

Exhaust after-treatment system and / or a motor vehicle, which - among other things, has an internal combustion engine. The measuring aerosol 8 is in particular an undiluted, undried and / or directly from a sampling point - for example, in the exhaust system or exhaust - diverted partial flow of the exhaust gas of the test specimen.

In the present embodiment, a condensation area 9 is provided in or along the main flow path 4 downstream of the nozzle device 6. In that

Condensation 9, the physical parameters are adjusted so that it comes to a supersaturation of the mixture, which is the carrier gas 3, the

Fuel 2 and the metered aerosol 8 includes, which in the Messaerosol 8

contained particles are increased by the condensing fuel 2.

After the condensation region 9, a measuring device 10 is arranged downstream of the main flow path 4. This measuring device 10 can be, for example, a conventional measuring device 10 of a condensation particle counter, which has, for example, a separating nozzle for separating the particles of the measuring aerosol 8. In particular, the measuring device 10 comprises an optical measuring device for the detection of particles.

Furthermore, the condensation particle counter 1 comprises a tempering arrangement 11, which is suitable and / or adapted to carry out a heating and optionally a cooling. In particular, extends through the entire

Condensation particle counter 1 a main channel 12 through which initially only the

Carrier gas 3 and subsequently also the fuel 2 and the measuring aerosol 8 are conveyed through. The tempering arrangement 11 may for example be designed such that a part, in the present case, the saturator 5, is heated. The condensation region 9 may for example have a temperature which is lower than the temperature in the region of the saturator 5, with which the physical Framework conditions in the course of the main channel 12 are modified such that first an enrichment or saturation of the carrier gas 3 with the fuel 2 takes place, and that then in the condensation region 9, for example by an active or passive cooling, comes to a supersaturation.

Conveniently, the carrier gas 3 is tempered during measurement operation of the temperature control assembly 11 in the saturator 5 to a saturation temperature, wherein the saturation temperature is greater than the temperature of the carrier gas 3 in the condensation region 9 and in particular greater than 200 ° C or 210 ° C. Accordingly, the carrier gas 3 is tempered in the measuring operation of the temperature control assembly 11 in the condensation region 9 to a condensation temperature of about 150 ° C, preferably from above 190 ° C.

In particular, by the tempering 11, the temperature of the

Messaerosols 8 are held in the condensation particle counter 1 above a certain minimum value, so that a condensation of contained in the metered aerosol

Steam or sulfuric acid vapor is avoided. Preferably, in all embodiments of the condensation particle counter, the minimum temperature is above the dew point temperature of water and / or above the dew point temperature of sulfuric acid. Conveniently, the temperature of the carrier gas 3 and / or the Meßaerosols 8 in the condensation region 9 is smaller than the saturation temperature but greater than 180 ° C, in particular greater than 190 ° C.

Optionally, it is provided that the Messaerosolstrom the Messaerosols 8 is heated so that the temperature of the Messaerosolstroms at each point of

Main channel 12 is greater than the acid dew point of the optionally contained in Messaerosolstrom acids, in particular sulfuric acid, wherein the acid dew point temperature is in particular in the range of 120 ° C to 150 ° C.

Accordingly, the condensation particle counter 1 according to the invention is designed as HT-CPC. In a HAT-CPC or high-temperature condensation particle counter formed condensation particle counter is the minimum temperature of the

Messaerosols in particular above the acid dew point of sulfuric acid.

The acid dew point temperature is usually in the range of 120 ° C to 150 ° C. The saturator 5 in the present embodiment comprises a saturation body 27, which comprises a plurality of saturation channels 28 along the main flow path 4. The saturation channels 28 are separated from each other by saturation channel walls 29. The saturator 5 comprises a saturation space 31 with a trough-shaped section 30. The shape and / or course of the saturation space 31 in the saturator 5 is adapted to the shape and / or the course of the saturation body 27.

The saturation space 31 is formed tubular along the main flow path 4. In - geodetic at its intended use - upper area, above the trough-shaped portion 30, a pressure compensation opening 35 is provided.

The saturation body 27 is in the present embodiment in the

Saturated space 31 is arranged and protrudes into the trough-shaped section 30. The saturation body 27 is according to a preferred embodiment, a porous body which is at least partially filled with the fuel 2 or impregnated and / or filled or impregnated. As it flows through the saturation channels 28, the carrier gas 3 is enriched or saturated with the fuel 2. For supplying the fuel 2, a fuel supply line 32 is provided, which is connected to a fuel reservoir 33. Moreover, in the present embodiment, the saturator 5 comprises the above-mentioned pressure equalizing port 35. In the present embodiment, the trough-shaped portion 30 may be partially or completely filled with the fuel 2. For this purpose, the trough-shaped section 30 is delimited by the lower part of the saturation space 31, which additionally comprises a step or shoulder along the main flow path before and after the saturation body 27, so that a trough is formed in which the preferably liquid-supplied operating material 2 is arranged can. The saturable body 27 also preferably protrudes into this trough-shaped section 30, as a result of which, through its porous structure, the operating material 2 soaks the entire saturable body 27, for example by capillary action.

For introducing the Meßaerosols 8 in the enriched with fuel 2 carrier gas 3, the nozzle device 6 is provided. The nozzle device 6 comprises a

Distributor nozzle 16, which is arranged in a nozzle portion 13 of the main channel 12. In particular, the distribution nozzle 16 is spaced from the wall 17 of the Nozzle section 13 is arranged, which results in the present embodiment, an annular gap into which the messaerosol 8 is introduced. The distributor nozzle 16 protrudes in the nozzle section 13 along the main flow path 4 projecting into the main channel 12 and includes a free end formed end portion 15. The end portion 15 of the distributor nozzle 16 is formed along the main flow path 4 in the nozzle portion 13 wedge-shaped or conically converging and thereby forms a Top. Shape and course of the main channel 12 in the nozzle section 13 are adapted shape and shape of the distributor nozzle 16. This is how the wall of the

Main channel 12 in the nozzle portion 13 of the outer contour of the distributor nozzle sixteenth

complained, whereby the main channel 12 in the nozzle portion 13 has an annular cross-section or is formed annular gap-shaped. The annular gap begins already upstream of the nozzle device 6 in the region of the meteraerosol feed line 7.

In the present embodiment, the condensation particle counter 1 is as

High-temperature condensation particle counter formed. This

Condensation particle counter 1 has the technical advantage that the messaerosol 8 can be supplied substantially unconditioned. Since the minimum temperature of Messaerosols 8 in the course of the relevant components of

Condensation particle counter 1 is above the dew point temperature of water and optionally also sulfuric acid, measurement errors are reduced, although the exhaust gas may be a substantially undried and substantially unfiltered exhaust gas of an internal combustion engine.

In order to be able to maintain stable operation despite the high temperatures, an alkane with the structural formula CnH 2n + 2 and an atomic number n between 16 and 24 is advantageously used as the fuel 2. Its isomers are also used. According to the present embodiment, an alkane having the structural formula C2oH ₄ 2, in particular eicosan, is used. The carrier gas used is an inert gas, in particular nitrogen. This prevents that despite the high temperature of the fuel 2 in the saturator 5 is oxidized, cracked or otherwise undesirable changes its molecular structure. Through the supply of the

Messaerosols 8 after the saturator 5 is additionally prevented that components of Messaerosols 8 affect the function of the saturator 5. In spite of the late Addition of the measuring aerosol 8 to effect a sufficient mixing of the measuring aerosol 8 with the enriched or saturated carrier gas 3, a specially designed nozzle device may be provided.

FIG. 2 shows a schematic illustration of a detail of the nozzle device 6, in particular of the nozzle device 6 from FIG. 1.

The main duct 12 comprises a nozzle section 13 with a wall 17. Within the main duct 12, in particular in the nozzle section 13, the distributor nozzle 16 is arranged at a distance from the wall 17. The distributor nozzle 16 thus protrudes centrally in the illustrated embodiment in the nozzle section 13 of the main channel 12

Distributor nozzle 16 extends substantially along the Flauptströmungspfads 4 and has, as already explained above, an end portion 15 which in the

present embodiment is designed as a free end.

The wall 17 of the nozzle portion 13 is substantially the course of

Distributor nozzle 16 adapted. By the present configuration, an annular channel is formed between the distributor nozzle 16 and the wall 17 of the nozzle portion 13, which is flowed through in the intended operation of the enriched carrier gas 3. In this annular channel the Meßaerosol 8 is mixed by the nozzle device 6. Flierzu has the distribution nozzle 16 an inlet opening 22 and an inlet channel 20 with a free inlet cross-section 18. Through this inlet opening 22, the messaerosol 8 is introduced into the distribution nozzle 16. Furthermore, the

Distributor nozzle 16 at least one outlet opening 19 for the distributed admixture of Messaerosols 8 in the enriched carrier gas. To connect the inlet opening 22 with the outlet opening 19 are an inlet channel 20 and at least one

Distribution channel 21 is provided. In the present embodiment, a plurality of outlet openings 19 are provided, of which in each case a distributor channel 21 runs in the direction of the inlet channel 20, in order thereby to pass through the inlet channel 20

Messaerosol 8 to distribute over the distribution channels 21 to all outlet openings 19.

The outlet openings 19 are embodied in an outlet section 26 of the distributor nozzle 16 on the circumference or on the jacket of the distributor nozzle 16. Preferably, the outlet openings along the circumference of the shell of the distributor nozzle 16 in a Row, in particular arranged directly next to each other, as partially in Fig. 4 can be seen. At the outlet section 26 of the end portion 15 includes - in particular directly - to.

The supply of Messaerosols 8 to the distribution nozzle 16 via the

Messaerosolzuleitung 7. In the present embodiment comprises the

Messaerosolzuleitung 7 a free end 24, which is directed to the inlet opening 22. In particular, the inlet opening 22 or the inlet channel 20 projects into the free end 24 of the measuring aerosol feed line 7. Furthermore, in the present embodiment, an overflow opening 23 is provided. Excess messaerosol 8, which is not introduced into the inlet opening 22 and the inlet channel 20 is over the

Overflow opening 23 removed. In particular, the free end 24 of the

Messaerosolzuleitung 7 a free cross-section 25 which is greater than that

Inlet cross section 18 and / or the inlet opening 22nd

In the present embodiment, the inlet cross section 18 of the inlet opening 22 and the inlet channel 20 is designed such that the inlet cross section 18 that element in the course of the flow in the distributor nozzle 16, which is the largest

Has flow resistance. The inlet cross section 18 thereby acts as a throttle or as a flow regulator. In the illustrated case a plurality of outlet openings 19, the free inlet cross section 18 is smaller than the smallest total outlet cross section of all outlet openings 19. In the case of a single outlet opening 19, not shown, the free inlet cross section 18 is smaller than the smallest overall cross section of all

Distribution channels 21 or, in the case of a single distribution channel 21, this

Distribution channels 21.

Conveniently, the free inlet cross section 18 is formed by a pipeline with a defined geometry. In particular, a pipe section with circular free

Provided cross-section, wherein the free diameter can be 0.5 - 1, 5 mm, preferably 0.7 mm. The length is provided with 10 - 25 mm.

The volume flow of the measuring aerosol 8 actually conveyed through the distributor nozzle 16 is essentially defined by the pressure difference between the inlet opening 22 and the outlet opening 19 due to this configuration. At known pressures can be determined by the well-known throttling effect of the inlet cross-section 18 of the volumetric flow of Messaerosols and in particular controlled or regulated become. The inlet channel 20 may be configured in all embodiments, in particular as a capillary, or comprise a capillary.

Thus, according to a preferred embodiment, the pressure in the region of the outlet opening 19 essentially corresponds to the ambient pressure. The pressure in the region of the inlet opening 22 corresponds to the back pressure of the through the metered aerosol. 8

flowed inlet opening 22nd

In an alternative embodiment, the pressure corresponds to the

Outlet opening 19 with respect to the ambient pressure of a negative pressure, wherein the pressure in the region of the inlet opening 22 substantially corresponds to the ambient pressure.

Preferably, the condensation particle counter is designed such that at least one control device for influencing, controlling or regulating the

Volume flow of the carrier gas 3 is provided that at least one

Control device for influencing, controlling or regulating the volume flow of Messaerosols 8 is provided, and that the two control devices at least part of a control device for controlling the dilution of the

Messaerosols by the carrier gas 3 form.

Preferably, the condensation particle counter is designed such that the

Control device, to adjust the dilution of Messaerosol 8 under

Consideration of the number of particles or particle density contained in the measuring aerosol 8, measured data of the measuring device 10 processed.

A control device for influencing, controlling or regulating a

Volume flow may, for example, include or be a controllable valve and / or a controllable delivery device such as a fan or a suction fan. By such a control device, the volume flow and thereby possibly also the pressure conditions in the course of the flow can be influenced. As a result of the special configuration of the distributor nozzle 16, the dilution of the measuring aerosol 8 by the carrier gas 3 can be regulated. The two Control devices are in such an embodiment part of a control device for controlling the dilution of Messaerosols. 8

In particular, the flow or the volume flow of Messaerosols 8 can be determined by the inlet channel 20 at known flow conditions, taking into account the pressure difference before and after the distributor nozzle 16 and thus optionally regulated by adjusting the pressure difference.

According to a first possible mode of operation, the carrier gas 3 can be conveyed through the main channel 12 in such a way that substantially ambient pressure prevails in the main channel 12 and thereby also in the region of the outlet openings 19 of the distributor nozzle 16. The dynamic pressure in the region of the inlet opening 22 can be controlled or regulated by means of a control or regulation of the volume flow of the supplied metering aerosol 8. The resulting pressure difference allows a

Determination of the volume flow of the introduced into the carrier gas 3 Meßaerosols 8. With known volume flow of the carrier gas, the dilution of Messaerosols 8 can be determined.

According to another possible mode of operation, the carrier gas 3 through the

Main duct 12 are sucked, the suction fan preferably after the

Measuring device 10 is provided. About one or more control valves can now be set in the main channel 12 a suppression. For example, in that

Area in which the carrier gas enters the condensation particle counter 1 and thereby also in the main channel 12, a flow regulator or flow valve may be provided. The supply of Messaerosols 8 through the Messaerosolzuleitung 7, for example, at sufficiently large dimensions of the overflow opening 23, substantially at ambient pressure. This configuration is the

Pressure difference before and after the distribution nozzle 16 known, whereby the dilution of Messaerosols 8 in the carrier gas 3 can be determined.

According to another possible mode of operation, both the pressure in the region of the inlet opening 22 of the distributor nozzle 16 and the pressure in the region of

Outlet opening (s) 19 of the distribution nozzle 16 differ from the ambient pressure, but be known or measurable, so that the pressure difference and the dilution can be determined.

According to a preferred embodiment, the control device may be connected directly or indirectly to the measuring device 10. In particular, measurement data of the measuring device are processed by the control device or

considered. As a result, the dilution can be adapted, for example, to the particle content of the measuring aerosol 8. If the messaerosol has a high particle content, the dilution can be increased. If the metered aerosol has a low particle content, the dilution can be reduced. This improves the measurement accuracy of the condensation particle counter. A change in the dilution can be made as described above.

In the present embodiment, the outlet openings 19 are funnel-shaped and expand outwardly from the distribution channel 21.

Conveniently, the distribution channel 21 is formed in a first section, subsequent to the inlet channel 20, with a constant cross-section and the cross-section increases in funnel shape at a certain distance from the inlet channel.

In the present embodiment, the distribution nozzle 16, the discharge opening 19 opens obliquely into the main channel 12. The opening angle is about 60 ° in the present embodiment. There are in particular eight holes with a

Diameter of about 1 mm and an inclination of about 50 ° to the vertical axis provided. This configuration is, as is preferred throughout the flow system, designed for a standard flow rate of 1 standard liter / min (1 NL / min, 1,000 sccm) for such systems. Of course, in the context of the present invention, an adaptation to other flow rates by appropriate constructive

Adaptations possible.

FIG. 3 shows a schematic sectional illustration of an embodiment of the invention

Condensation particle counter, in particular of the condensation particle counter of Figure 1, wherein the sectional plane is substantially a normal plane of

Flow channel in the saturator 5 is. The sectional plane passes through the saturation body 27, the saturation channels 28, the saturation channel walls 29, the Saturation space 31, the trough-shaped portion 30 of the saturation space 31 along the fuel supply line 32 through the fuel reservoir 33, the

Level control device 34 and through the pressure compensation opening 35th Die

Level control device 34 is provided for controlling the level of the fuel 2 in the fuel reservoir 33 and is set up via the fuel supply line 32 for controlling or controlling the fuel supply to the saturation body 27.

Due to the special arrangement of the fuel supply line 32, the trough-shaped section 30 and the operating fluid reservoir 33 are in the form of communicating vessels

trained or act as communicating vessels. By means of a filling level control in the operating fluid reservoir 33, the filling level in the trough-shaped section 30 can also be controlled or regulated. Flierzu the fuel supply line 32 is annular and connected from below to the trough-shaped portion 30 and the fuel reservoir 33.

The saturation body 27 is in the present embodiment, at least partially, preferably formed entirely of a porous material, in particular of a porous alumina ceramic material. The saturable body 27 protrudes into the trough-shaped section 30, which is at least partially filled with the operating material 2. Due to the porous structure of the saturation body 27 is automatically with the

Fuel 2 soaked. The saturation body 27 comprises a plurality of saturation channels 28, which are flowed through during normal operation of the carrier gas 3.

The saturation channel walls 29, through which the saturation channels 28 are formed, or which extend between the saturation channels 28, are also at least partially formed of the porous material and impregnated with the fuel 2. Now, if the saturation space 31 flows through the carrier gas 3, the carrier gas 3 flows through the saturation channels 28 and is thereby enriched or saturated via the saturation channel walls 29 with the fuel 2.

Figure 4 shows a schematic oblique view of an embodiment of a

Distributor nozzle 16, in particular the distribution nozzle 16, from Figures 1 and 2. The distribution nozzle 16 includes a plurality of outlet openings 19. In this embodiment the outlet openings 19 are arranged distributed along the circumference or the jacket of the distributor nozzle 16. According to this embodiment, the outlet openings 19 are arranged substantially obliquely radially distributed and evenly spaced on the distributor nozzle 16. In particular, the outlet openings 19 are arranged in a row next to one another. The outlet openings 19 are funnel-shaped and extend from the cross section of the distribution channels 21 to the outside. As a result, the outlet openings 19 act as a kind of diffuser, whereby a

improved mixing is effected in the admixture of Messaerosols in the carrier gas.

Good mixing is advantageous in all embodiments, so that the particles can grow separately from each other and thus individually by accumulation of the fuel without coincidence errors. This is promoted in particular by the design measures of a laminar flow, an adapted flow velocity and / or the design of the nozzle device 6.

The distributor nozzle 16 has an end portion 15 which serves as the free end of the

Distributor nozzle 16 is formed. In the present embodiment, the

End portion 15 formed conically converging, whereby on the

End portion 15 is formed a tip.

FIG. 5 shows an embodiment of a saturation body 27, in particular of the saturation body 27, of FIGS. 1 and 3. The saturation body 27 preferably has a shape adapted to the shape of the saturation space 31. In the present embodiment, the saturation body 27 is cylindrically shaped. The

Saturation body 27 has a multiplicity of saturation channels 28, which preferably run along the main main flow path 4. In particular, the profile of the main flow path 4 is determined by the course of the saturation channels 28. The saturation channels 28 are in the present embodiment by the

Saturation channel walls 29 formed. These run in the present

Embodiment honeycomb or grid-shaped along the Flauptströmungspfads 4 by the saturation body 27. This show the honeycomb or grid-shaped

Saturation channels 28 of the embodiment of Figure 5 a substantially rectangular or square cross section. Preferably, the cross section of the saturation channels 28 in the course of the saturation channels 28 along the

Main flow path 4 constant. The saturation channels 28 take in one

Normal plane of the main flow path 4 more than 70%, preferably more than 80%, of the cross-sectional area of the saturation body 27, wherein incomplete

Saturation channels 28 are not taken into account at the edge of the saturation body 27.

The saturation body 27 is formed according to a preferred embodiment of a porous alumina ceramic material. This material exists

preferably more than 80% of a mixture of Al2O3 and S1O2. Conveniently, the alumina ceramic contains 45-55% (eg, 51.7%) Al2O3 and / or 38-45% (eg, 42%) S1O2. In one variant of the invention, 3-5% K 2 O, in particular 4.1% K 2 O, are additionally present, with further constituents in addition, such as Fe 2 O 3, TIO 2, CaO, MgO and / or Na 2 O, in each case being present in the range of or below 1% can. In this case, the alumina ceramic preferably has a density of 2-3, in particular of 2.7 g / cm ³ according to the hydrostatic method DIN VDE 0335/2 and a water absorption of less than 0.1%, in particular of 0% according to the hydrostatic method DIN VDE 0335 / 2 on.

The saturable body 27 or the aluminum oxide ceramic material advantageously has a porosity which has a sufficient capillary action for the operating medium or the operating material 2. For example, a saturation body 27 with a diameter of about 2.5 cm should be completely wetted or soaked, for example, if it is about 1/5 deep in the fuel 2.

A method for operating a condensation particle counter 1 according to the invention provides that a carrier gas 3 - in particular an inert gas such as, for example, an inert gas. Nitrogen - is conveyed along a main flow path 4 through the condensation particle counter 1, wherein the carrier gas 3 in the flow through the

Condensation particle counter 1 along the main flow path 4 of a

Temperieranordnung 11 is at least partially tempered. Along the main flow path 4 is successively: - The carrier gas 3 by a saturator 5 with a fuel 2 - in particular an alkane with the structural formula CnH2n + 2 and an atomic number n between 16 and 24 or associated isomers, for example with structural formula C2oH ₄ 2 and in particular eicosan - enriched or saturated;

- The enriched carrier gas 3 by a nozzle device 6, a messaerosol 8 added;

- The mixture containing the carrier gas 3, the fuel 2 and the messaerosol 8 supersaturated in a condensation region 9; and

- Detected by the condensed resource enlarged particles of Messaerosols 8 in a measuring device 10.

Carrier gas 3 and 8 Messaerosol be tempered in measuring operation of the temperature control assembly 11 in the condensation region 9 to a condensation temperature of about 150 ° C, preferably from above 190 ° C.

FIGS. 1 to 5 preferably relate to a single advantageous embodiment of a condensation particle counter according to the invention or an arrangement according to the invention comprising a condensation particle counter.

In principle, however, the nozzle device 6 and in particular the distributor nozzle 16 can also be used to improve the admixture of Messaerosols in a

conventional condensation particle counter can be used.

In principle, the saturator 5 and in particular the saturation body 27 as well as the control of the filling level in the saturation space can be used in a conventional condensation particle counter.

Claims

claims

1. Condensation particle counter (1) comprising:

a main channel (12) through which a carrier gas (3) flows during the measuring operation along a main flow path (4),

- A saturator (5) for enrichment, in particular for saturation, of

Carrier gas (3) with a fuel (2), wherein the saturator (5) comprises a saturable with the fuel (2) and impregnated in the measuring mode saturable body (27), and wherein the saturable body (27) at least one of

Main flow path (4) following saturation channel (28) for the passage and enrichment of the carrier gas (3),

- a nozzle device (6) opening along a main flow path (4) downstream of the saturator (5) into a nozzle section (13) of the main channel (12) and connected to a meteraerosol feed line (7) for introducing a particle laden measuring aerosol (8) into the enriched carrier gas (3) is set up,

a condensing region (9) arranged along the main flow path (4) downstream of the nozzle device (6) for supersaturation of the mixture containing the carrier gas (3), the operating material (2) and the measuring aerosol (8),

a measuring device (10) arranged downstream of the main flow path (4) downstream of the condensation region (9) for detecting the particles of the measuring aerosol (8) which are enlarged by the condensed fuel,

- And a tempering arrangement (11) for controlling the temperature of the carrier gas, characterized in that

the saturation body (27) is at least partially, preferably completely formed of a porous aluminum oxide ceramic material.

2. Condensation particle counter (1) according to claim 1,

characterized in that

the alumina ceramic material consists of over 80% of a mixture of Al2O3 and S1O2.

3. Condensation particle counter (1) according to claim 1 or 2, characterized in that

the alumina ceramic contains 45-55% Al 2 O 3.

4. Condensation particle counter (1) according to one of claims 1 to 3,

characterized in that

the alumina ceramic material contains 38-45% S1O2.

5. Condensation particle counter (1) according to one of claims 1 to 4,

characterized in that

the alumina ceramic contains 51.7% Al2O3 and 42% S1O2.

6. Condensation particle counter (1) according to one of claims 1 to 5,

characterized in that

the alumina ceramic material in addition to Al2O3 and S1O2 also 3-5% K2O, in particular 4.1% K2O contains.

7. Condensation particle counter (1) according to one of claims 1 to 5,

characterized in that

the alumina ceramic next to AI2O3, S1O2 and K2O more

Ingredients such as Fe203, T1O2, CaO, MgO and / or Na20, each in the range of or below 1%.

8. Condensation particle counter (1) according to one of claims 1 to 7,

characterized in that

the alumina ceramic material has a density of 2-3 g / cm ³ , in particular of 2.7 g / cm ³ according to the hydrostatic method DIN VDE 0335/2.

9. Condensation particle counter (1) according to one of claims 1 to 8,

characterized in that

the aluminum oxide ceramic material has a water absorption of less than 0.1%, in particular of 0%, according to the hydrostatic method DIN VDE 0335/2.

10. Condensation particle counter (1) according to one of claims 1 to 9, characterized in that

the saturation body (27) comprises a plurality of saturation channels (28) which extend side by side along the main flow path (4) through the saturation body (27), the saturation channel walls (29) arranged between the saturation channels (28) being in contact with the fuel (2) during measurement operation. are soaked.

11. Condensation particle counter (1) according to claim 10,

characterized in that

the saturation passage walls (29) extend in honeycomb or raster shape along the main flow path (4) through the saturation body (27), thereby forming a plurality of honeycomb or raster-shaped saturation passages (28).

12. Condensation particle counter (1) according to one of claims 1 to 11,

characterized,

- That the saturation body (27) in a trough-shaped portion (30) of a saturation space (31) of the saturator (5) is arranged,

- And that the trough-shaped portion (30) at least partially with the

Fuel (2) is filled.

13. Condensation particle counter (1) according to claim 12,

characterized,

- That a fuel supply line (32) opens into the trough-shaped portion (30) of the saturator (5),

- That the fuel supply line (32) is connected to a fuel reservoir (33),

- And that the trough-shaped portion (30) and the operating fluid reservoir (33) are formed by the connection with the fuel supply line (32) as communicating vessels or act.

14. Condensation particle counter (1) according to claim 13, characterized in that

a level control device (34) for controlling the level of the

Fuel (2) in the fuel reservoir (33) is provided, and that the level control device (34) via the fuel supply line (32) is arranged for controlling or controlling the fuel supply to the saturation body (27).

15. condensation particle counter (1) according to any one of claims 12 to 14,

characterized in that

the saturation space (31) is tubular along the main flow path (4) and comprises a pressure compensation opening (35) in the upper region, above the trough-shaped section (30),

and / or that the shape and / or the course of the saturation space (31) in the saturator (5) is or are adapted to the shape and / or the course of the saturation body (27).

16. Condensation particle counter (1) according to one of claims 1 to 15,

characterized in that

the saturation channels (28) in a normal plane of the main flow path (4) more than 70%, preferably more than 80%, of the cross-sectional area of

Occupy satiety body (27), with incomplete saturation channels (28) are not taken into account at the edge of the saturation body (27).