AT524348A1 - Method and device for particle measurement - Google Patents

Abstract

In order to provide an improved device (23) for determining at least one measured variable of solid particles (P) in a test aerosol fluid flow (TA), which enables a wider range of applications and increases the reliability of the measurement, the invention provides that in a measuring section (MA) the device (23) has at least one optical measuring device (1) which is designed to determine at least one measured variable of the solid particles (P) of the test aerosol fluid flow according to an optical measuring principle and that in the measuring section (MA) there is also at least one electrical measuring device (13) is provided, which is designed to determine at least one measured variable of the solid particles (P) in the same test aerosol fluid flow (TA) according to an electrical measuring principle.

Description

15

20

25

30

35

AV-4223AT

Method and device for particle measurement

The invention relates to a method for determining at least one measured variable of solid particles in a test aerosol fluid flow that is passed through a measuring section, and a device for determining at least one measured variable of solid particles in a test aerosol fluid flow, the device having a measuring section for determining the at least one metric in the test aerosol fluid flow

is provided.

Various methods and devices are known for measuring exhaust gas from internal combustion engines, with which one or more exhaust gas components of interest can be measured in the exhaust gas. The exhaust gas components include components that result directly from the combustion process, but also components that result, for example, from exhaust gas aftertreatment downstream of the combustion. The exhaust gas components include, for example, non-toxic components such as carbon dioxide (CO2). Of particular interest are the components that are toxic to humans, such as unburned hydrocarbons (HC), carbon monoxide (CO), particles (PM) and nitrogen oxides (NO, NO2 or NOx in general). Exhaust aftertreatment systems are often used to reduce certain exhaust gas components, such as 3-way catalytic converters, systems for selective catalytic reduction (so-called SCR catalytic converters), etc. SCR catalytic converters, for example, use ammonia (NH3) as an additive to chemically reduce nitrogen oxides used, which is provided e.g. in the form of a urea solution. In this case, parts of the ammonia, the

also occur as an exhaust gas component in the exhaust gas when the SCR catalytic converter does not react.

For example, measuring devices based on an optical measuring principle, such as condensation particle counters (also called condensation particle counters or CPCs), are known for measuring particle emissions (particulate matter - PM). Condensation particle counters are optical measuring devices for detecting small solid particles with dimensions in the nm range, for example, in an aerosol, e.g. air, engine exhaust gas, etc. Condensation particle counters are used, for example, in clean room technology or for measuring solid particles (e.g. soot, fine dust) in exhaust gas flows, e.g. from internal combustion engines . Solid particles in the nm range are too small to be directly detected optically. In order to make such solid particles measurable anyway, condensation particle counters are used, in which the aerosol is saturated in a saturation unit with vapors from an operating medium, e.g. water or an alcohol. The solid particles then serve as condensation nuclei and are in a condensation unit downstream of the saturation unit, in which the

saturated aerosol is cooled by heterogeneous condensation of the operating medium

2123”

15

20

25

30

35

AV-4223AT

Enlarged to such an extent that they can be optically detected in a subsequent optical measuring cell, for example to count the particles or to determine the particle sizes. The size of the solid particles from which this condensation process takes place depends on the saturation and is referred to as the Kelvin diameter. The smaller the Kelvin diameter for a certain saturation with the operating fluid, the smaller the solid particles that lead to the condensation of operating fluid can be. Condensation particle counters are known, for example, from EP 462 413 B1, US Pat. No. 5,118,959 A or WO 22017/085183 A1.

Furthermore, electrical measuring devices based on an electrical measuring principle are also known for measuring solid particles in an aerosol, for example diffusion charging measuring devices, also known as “diffusion charger” or “electronic particle counter—EPC”. Particles in the aerosol are electrically charged and then detected using a suitable measuring cell in order to make statements about the particles in the aerosol. With such devices and methods, for example, a particle size distribution, a particle number and/or an average particle diameter can be measured. Such a measuring device is known, for example, from WO 2004/113904 A1. However, the measurement of the particle number concentration depends

for example on the size of the particles, which limits the measuring range.

In particular in the field of exhaust gas measurement from combustion engines, the requirements for particle measurement technology have recently increased, which is not least due to the increasingly strict legal regulations with regard to the maximum permissible pollutant emissions. This creates an ongoing need for new methods and devices that can be used to increase the accuracy and reliability of aerosol measurement in all areas of application, but especially in the field of exhaust gas measurement technology. WO 2007/067822 A2, for example, discloses a combination of the two measuring principles mentioned above. A measuring flow is divided into two partial flows, with condensation particle counting being carried out on one partial flow and a diffusion charging measurement being carried out on the other partial flow. However, this does not give any results that go beyond the measurement result of the respective measurement principle

Information.

It is therefore an object of the present invention to provide an improved method and an improved device for measuring particles in an aerosol

enable a wider range of applications and increase the reliability of the measurement.

The object is achieved with the method mentioned in that in the measurement section at least one detection of the same test aerosol fluid stream

Measured variable according to an optical measuring principle and at least one detection of

3123”

15

20

25

30

35

AV-4223AT

Measured variable is carried out according to an electrical measuring principle. beneficial

Refinements of the method are specified in claims 2 to 9.

The object is further achieved with a device in that at least one optical measuring device is arranged in the measuring section, which is designed to determine at least one measured variable of the solid particles of the test aerosol fluid flow according to an optical measuring principle and that at least one electrical measuring device is additionally provided in the measuring section is designed to determine at least one measured variable of the solid particles in the same test aerosol fluid flow according to an electrical measuring principle. Advantageous configurations of the device are set out in claims 11 to 17

specified.

Through the advantageous combination of the two measuring principles (optical and electrical) in the same fluid flow, an added value of information about the particles contained in the fluid flow can be obtained, which exceeds the sole application of only one of the two measuring principles. Although both measuring principles are suitable for measuring a particle number concentration after appropriate signal evaluation, the measuring principles differ significantly. In the optical measurement, e.g. by means of a condensation particle counter or CPC mentioned above, a count of individual particles is carried out. On the other hand, in the electrical measurement, for example with the diffusion charging measurement method or EPC mentioned at the outset, a correlation to the particle number concentration is produced by detecting an average electrical charge distribution of a particle cloud. However, this correlation is related to the particle size, which limits the available measuring range when an EPC is used alone. The inventive combination of optical measurement, in particular CPC, and electrical measurement, in particular EPC, can now be used to obtain additional information for the measurement result of the respective other measurement from the measurement result of one measurement. For example, the particle number concentration measured by CPC can advantageously be used to calculate the correlation between particle number concentration and particle size

to obtain particle size information from the EPC measurement result.

The present invention is explained in more detail below with reference to FIGS. 1 to 3e, which are advantageous by way of example, diagrammatically and not by way of limitation

Show configurations of the invention. 1 shows a condensation particle counting device, FIG. 2 shows a diffusion charging measuring device,

3a-3e each a schematic representation of an advantageous embodiment

the device according to the invention or the method.

4123”

15

20

25

30

35

AV-4223AT

1 shows an optical measuring device 1 for detecting a measured variable of solid particles P in a test aerosol fluid flow TA according to an optical measuring principle. For example, a particle number and/or a particle number concentration and/or a particle mass and/or a particle size of the solid particles P can be determined as a measured variable. The optical measuring device 1 is designed here in the form of the initially mentioned condensation particle counting device. The condensation particle counting device in the embodiment shown has at least one saturation unit S with a reservoir 2 for an operating medium B, a condensation unit K downstream of the saturation unit S in the direction of flow and an optical measuring cell OM. A measuring channel 3 for the test aerosol fluid flow TA, in which the solid particles P are contained, runs through the condensation particle counting device

are.

The test aerosol fluid flow TA can be fed to the measuring channel 3 through an inlet 4 and removed again through an outlet 5, as indicated by the arrows in FIG. The test aerosol fluid flow TA sequentially first passes through the saturation unit S, in which an atmosphere saturated with the operating medium B, e.g. alcohol such as butanol, or water, is generated. The operating medium B can, for example, be fed to the measuring channel 3 inside the saturation unit S via a porous wall layer, e.g. a so-called wick 6. In the case of butanol as operating medium B, the temperature in the saturation unit S can be, for example, 25° C., with this being optionally maintained and maintained by a suitable heating device (not shown).

can be changed if necessary.

After the saturation unit S, the saturated test aerosol fluid stream TA flows via the measuring channel 3 into the subsequent condensation unit K, in which the temperature of the test aerosol fluid stream TA is reduced to around 8° C., for example, by cooling. As a result of the cooling, the operating medium B condenses on the solid particles P in the test aerosol fluid flow TA. As a result, each solid particle P grows into a condensate droplet 7, which is large enough to be able to be detected by the downstream optical measuring cell OM. When measuring exhaust gases from internal combustion engines, the original solid particles P can be present, for example, on the order of -100 nm, with the condensate droplets 7, for example

grow to a diameter of about 5-20 µm.

Since the solid particles P only act as condensation nuclei, their size has only a minor effect on the size of the condensate droplets 7 . From the condensation unit K, the accumulated solid particles P reach the optical measuring cell OM, which is shown only schematically in FIG. We is shown in Fig.1, the flow pattern in the

Measuring channel 3 of the condensation unit K, for example, in the vertical direction of

5/23"

15

20

25

30

35

AV-4223AT

run from bottom to top. Of course, a straight flow path would also be possible. Subsequent to the optical measuring cell OM, for example, a suitable conveying device 8, such as a vacuum pump, can be provided with which a specific

predetermined or adjustable flow in the measuring channel 3 can be generated.

The optical measuring cell OM can, for example, have a scattered light measuring device which has a suitable light source 9, e.g. a laser light source, and a suitable light sensor 10. The light source 9 and the light sensor 10 are arranged in such a way that a change in the incidence of light measured by the light sensor 10, which occurs when a condensate droplet 7 crosses the beam path of the light source 9, is registered by a computing unit 11 and used to determine the measured variable, in particular e.g Determination of a particle number of the solid particles P is evaluated. The computing unit 11 can be part of the optical measuring cell OM, but could also be part of a higher-level control unit, for example. For example, the optical measuring cell OM could be used on an engine or vehicle test bench to measure the in the exhaust gas

contained solid particles, such as soot particles are used.

The computing unit 11 of the optical measuring cell OM could then be integrated, for example, in a test bench control unit 12 of the test bench, which can be provided to control a test run of the test specimen (e.g. internal combustion engine or complete vehicle) set up on the test bench. Of course, the embodiment shown is only to be understood as an example and it is known that a condensation particle counting device can be implemented in detail in different ways, the essential components, namely the saturation S, condensation K and optical evaluation OM,

remain.

2 shows a schematic representation of an electrical measuring device 13 for detecting a measured variable of solid particles P in a test aerosol fluid flow TA according to an electrical measuring principle. A particle number and/or a particle number concentration and/or a particle mass and/or a particle size of the solid particles P can in turn be determined as a measured variable. The electrical measuring device 13 is designed here in the form of the diffusion charging measuring device mentioned at the outset. The test aerosol fluid flow TA flows through the electrical measuring device 13 along a measuring channel 14 and sequentially runs through at least one charging unit L and then at least one electrical measuring cell EM. The charging unit L may include a charger 15 and a particulate separator 16, for example.

The electrical charge in the charger 15 can, for example, by an ion current or

an ion cloud carried out by a corona wire 17 to an ion trap 18

6123”

15

20

25

30

35

AV-4223AT

becomes. For example, a simple electrode can be used as the ion trap 18 . The corona wire 17 is preferably located in a suitable corona chamber 19, which can be arranged, for example, on the side of the flow channel 14 and can be separated by a blocking grid 20. The ions generated by the corona wire 17 in the corona chamber 19 penetrate through the blocking grid 20 and migrate through the measuring channel 14, essentially transversely to the flow direction of the test aerosol fluid stream TA, to the ion trap 18 arranged on the opposite side. The solid particles P

electrically charged when passing through the ion stream or ion cloud.

The charger 15 can, for example, be operated “statically”, i.e. with an ion current that is constant over a predetermined time period, as indicated above the ion trap 18 in FIG. As a result, all solid particles P test aerosol fluid flow TA are charged substantially uniformly and then reach the particle separator 16 downstream in the measuring channel 14. The particle separator 16 can be based on the electrostatic principle, with an electric field being generated between opposite electrodes 21a, 21b, which charged Solid particles P to a so-called collecting electrode, here electrode 21b, derived and thereby removed from the test aerosol fluid stream TA, as long as the electrodes 21a, 21b are charged. The electrodes 21a, 21b of the particle separator 16 can, for example, be charged in a pulsed manner at a defined frequency, as indicated above the electrode 21b in FIG

and uncharged sections arises, as indicated in Fig.2.

The charged portions contain the particulate matter P charged by the charger 15, while substantially all the particulate matter P is removed in the uncharged portions. This alternating sequence of charged and uncharged sections generates a displacement current in the electrical measuring cell EM, which can be evaluated to determine the measured variable of the solid particles P (e.g. particle concentration, number of particles, particle size, size distribution of the particles P, etc.), as shown in Fig.2 is indicated above the electrical measuring cell EM. Instead of the constant "static" charging in the charger 15 and the pulsed, sectional removal in the particle separator 16, a pulsed, sectional charging in the charger 15 could also take place directly. The particle separator 16 would not be required in this case and the alternating sequence of charged and uncharged sections of the test aerosol fluid stream TA could directly

electrical measuring cell EM are supplied.

In the electric measuring cell EM, the displacement current can be detected and evaluated, which is caused by the solid particles P charged in sections when they flow through the electric measuring cell EM. As electric

Measuring cell EM can, for example, use a sufficiently sensitive electrometer

11237

15

20

25

30

35

AV-4223AT

will. For example, the electrical measuring cell EM can comprise a conductive tube through which the test aerosol fluid flow TA with the solid particles P charged in sections is conducted. The displacement current can be measured on the tube according to the principle of induction. By evaluating the height of the positive and negative value peaks of the displacement current, conclusions can be drawn about the charge and thus about the particle number of the solid particles P in the test aerosol fluid flow TA

will.

The distances between the value peaks can be influenced by a pulse duration of the charging in the charging unit L and/or by the particle separator 16 used. After the electrical measuring cell EM, the test aerosol fluid flow TA leaves the electrical measuring device 13 , with a downstream conveying device 22 , for example a suction pump, possibly being provided in order to generate a specific predetermined or adjustable flow rate in the measuring channel 14 . Of course, the electrical measuring device 13 shown is only to be understood as an example and, as is known, could also be designed differently in detail, although the measuring principle remains the same.

According to the present invention, the optical measuring principle or the optical measuring device 1 explained by way of example with reference to FIG. 1 and the electrical measuring principle or the electrical measuring device 13 explained by way of example with reference to FIG. as explained in detail below with reference to FIGS. 3a-3e. 3a-3e schematically show advantageous configurations of the invention, the blocks with the same reference numbers as in FIG. 1 and FIG. 2 corresponding to the respective components or method steps. One

renewed detailed description is therefore no longer provided separately.

The device 23 according to the invention has a measuring channel 24 for (at least) the test aerosol fluid flow TA, in which the solid particles P are contained. For example, suitable connections 25 , 26 for supplying and removing the test aerosol fluid flow TA to the measuring channel 24 can be provided on the device 23 . The device 23 could, for example, also have a suitable conveying device (not shown), for example a vacuum pump, in order to generate a fixed or adjustable flow rate. The conveying device can be part of the device 23 , but could also be located downstream of the device 23 . In the measuring channel 24 there is a measuring section MA for determining at least one measured variable of the solid particles

P provided in the test aerosol fluid flow TA.

For this purpose, at least one optical measuring device is arranged in the measuring section MA

is designed to measure at least one variable of the solid particles P of the test aerosol

15

20

25

30

35

AV-4223AT

To determine fluid flow TA according to an optical measuring principle. In addition, at least one electrical measuring device is provided in the measuring section MA, which is designed to determine at least one measured variable of the solid particles P in the same test aerosol fluid flow TA according to an electrical measuring principle. With the optical measurement principle, for example, a particle number and/or a particle number concentration and/or a particle mass and/or a particle size of the solid particles P can be determined as a measured variable. In an analogous manner, with the electrical measuring principle, for example, a particle number and/or a particle number concentration and/or a particle mass and/or a particle size

Solid particles P are determined as a measurand.

The measurand of the optical measuring principle can be the same as or different from the measurand of the electrical measuring principle. The optical measuring principle preferably comprises a plurality of sequential method steps, with at least one measuring device component 27 being provided for carrying out each method step of the optical measuring principle. The electrical measurement principle preferably also comprises a plurality of sequential process steps, with the implementation of each process step of the electrical

Measuring principle at least one measuring device component 28 is provided.

A condensation particle counter for carrying out a condensation particle count is advantageously provided as the optical measuring device in the device 23 and a diffusion charging measuring device for carrying out a diffusion charging measurement is preferably provided as the electrical measuring device. As has already been described in detail with reference to FIG. As already described in detail with reference to FIG

Measurand have proportional electrical measurand.

Furthermore, one or more further connections and/or interfaces (not shown) can also be provided on the device 23 . For example, one or more connections for supplying energy to the device 23 or the measuring device components 27, 28 contained therein can be provided and/or one or more connections for supplying or removing an operating medium B can be provided

be. Furthermore, a data transmission interface could also be connected to the device 23

9/23”

15

20

25

30

35

AV-4223AT

be provided, for example by the device 23 for measuring data acquisition and/or evaluation with a higher-level control unit, e.g

Test bench control unit 12 (see Fig. 1) to connect.

Of course, it would also be conceivable for one or more computing units (see, e.g., FIG. 1) to be provided in the device 23 for the evaluation and, if necessary, further processing of the measured variable(s) recorded. For example, a computing unit could be designed to compare a measured variable determined using the optical measuring principle with a measured variable determined using the electrical measuring principle, for example in order to validate a measured variable. In the computing unit, however, a directly or indirectly recorded measured variable could also be converted to another variable, etc. A measured variable recorded using the optical measuring principle, e.g. the particle number or particle number concentration, could also be used to convert from a measured variable recorded using the electrical measuring principle Measured variable to gain additional information, for example from the aforementioned correlation between the measured with the electrical measuring device particle number concentration and the particle size. In addition, a memory unit (not shown) could also be in the device 23, for example

be provided to store measurement results.

In particular, if the device 23 is intended for sole autonomous use (e.g. independently of a test stand), a user interface (not shown) and/or a display unit can also be provided, for example. The user interface can be provided, for example, to put the device 23 into operation or to make certain settings, for example selecting a measured variable, a measuring range, etc. The display unit could, for example, display measurement results and/or an operating state of the device 23 could be output . For example, it could only be signaled whether and when the device 23 is ready for operation, or it could also be displayed, for example, if an error condition is present. Temperatures, pressures, flow rates, etc. could also be measured and possibly set via the user interface and/or output via the display unit.

The display of a resource fill level would also be conceivable, for example.

According to an advantageous embodiment, it can be provided that at least one measuring device component 27 of the optical measuring device and at least one measuring device component 28 of the electrical measuring device are arranged in the measuring section MA of the device 23 such that the respective method step of the optical measuring method and the respective method step of the electrical measuring method are at least can be carried out partially in parallel on the test aerosol fluid flow TA, as shown by way of example in FIGS. 3a and 3b. In the example according to FIG. 3a, the

Test aerosol fluid flow TA first the charger L of the electrical measurement principle, where

"-9

15

20

25

30

35

AV-4223AT

the solid particles P are electrically charged. The test aerosol fluid stream TA then continues to flow through the measuring channel 24 and passes through the saturation unit S, the (charged) test aerosol fluid stream TA being saturated with the vapor of a resource B (FIG. 1). The (charged and saturated) test aerosol fluid flow TA then continues to flow through the measuring channel 24 and passes through the condensation unit K. The test aerosol fluid flow TA is cooled in the condensation unit K, so that the

Equipment B condensed on the solid particles P.

Finally, the test aerosol fluid stream TA continues to flow with the now charged condensate droplets and runs at least partially in parallel through the optical measuring cell OM, in which the optical measurement of the measurand takes place, and the electrical measuring cell EM, in which the electrical measurement of the measurand or a proportional electrical measurand he follows. In the context of the invention, parallel means that at least parts of the method steps carried out in the respective measuring device components 27, 28 are carried out simultaneously. For this purpose, the measuring device components 27, 28, the optical measuring cell OM and the electrical measuring cell EM in FIG. Of course, instead of two separate measuring device components 27, 28, a single combined measuring device component could be provided, which is suitable for carrying out the respective method step of the optical measuring principle and the respective method step of the electrical measuring principle. The arrangement of the optical measuring cell OM and the electrical measuring cell EM according to FIG. 3a has the advantage that the optical and electrical measurement take place at the same time, so that there is better correlation and comparability of the measurement results compared to a locally separate measurement

given is.

A further variant of the at least partially parallel execution of method steps of the optical and electrical measuring principle is shown in FIG. 3b. In this case, the test aerosol fluid flow TA first passes through the saturation unit S, with the test aerosol fluid flow TA being saturated with the vapor of an operating medium B (FIG. 1). The (saturated) test aerosol fluid flow TA then continues to flow through the measuring channel 24 and passes through the condensation unit K, in which the test aerosol fluid flow TA is cooled, so that the operating medium B condenses on the solid particles P. The test aerosol fluid flow TA then continues to flow with the condensate droplets and runs at least partially in parallel through the optical measuring cell OM, in which the optical measurement of the measurand takes place, and the charging unit L of the electrical measuring principle,

in which the solid particles P or condensate droplets are electrically charged.

11/23”

15

20

25

30

35

AV-4223AT

Finally, the (charged) test aerosol fluid stream TA continues to flow through the measurement channel 24 and passes through the electrical measurement cell EM, in which the electrical measurement of the measured variable or a proportional electrical measured variable takes place. In the example according to FIG. 3b, essentially the last of the sequential method steps of the optical measuring principle (optical measuring cell OM) and the first of the sequential method steps of the electrical measuring principle (charging unit L) are carried out at least partially in parallel. A compact

Device 23 are created.

According to a further advantageous embodiment, at least one measuring device component 27 of the optical measuring device and at least one measuring device component 28 of the electrical measuring device can be arranged in the measuring section MA of the device 23 such that the method steps of the optical measuring principle and the method steps of the electrical measuring principle can be carried out at least partially in alternation, such as is explained with reference to Fig. 3c. Here, the test aerosol fluid flow TA first runs through the charging unit L of the electrical measuring principle, with the solid particles P being electrically charged. The test aerosol fluid stream TA then continues to flow through the measuring channel 24 and passes through the saturation unit S, with the (charged) test aerosol fluid stream TA containing the vapor of a resource B

(Fig.1) is saturated.

The (charged and saturated) test aerosol fluid stream TA then continues to flow through the measurement channel 24 and passes through the electrical measurement cell EM, in which the electrical measurement of the measured variable or a proportional electrical measured variable takes place. The test aerosol fluid stream TA then flows through the measuring channel 24 to the condensation unit K, in which the test aerosol fluid stream TA is cooled, so that the operating medium B condenses on the solid particles P. Finally, the test aerosol fluid flow TA with the now charged condensate droplets continues to flow and passes through the optical measuring cell OM, in which the optical measurement of the measurand takes place. The alternating arrangement of the measuring device components 27, 28 of the optical and electrical measuring principle can ensure that the respective method steps do not adversely affect one another. Since the electrical measurement takes place in the electrical measuring cell EM before the condensation in the condensation unit K, it is possible to avoid any precipitation of condensate droplets on the electrical measuring cell EM, which would occur in the reverse order

could occur.

According to a further advantageous embodiment of the invention it is provided that the

Measuring device components 27 of the optical measuring device and the

-11

15

20

25

30

35

AV-4223AT

Measuring device components 28 of the electrical measuring device are arranged on the device 23 in such a way that all process steps of the optical measuring principle can be carried out first and then all process steps of the electrical measuring principle can be carried out or vice versa. An example of this is shown in Figure 3d. Here, the test aerosol fluid flow TA first runs through the charging unit L of the electrical measuring principle, in which the solid particles P or condensate droplets are electrically charged. The (charged) test aerosol fluid flow TA then continues to flow through the measuring channel 24 and passes through the electrical measuring cell EM, in which the electrical measurement of the measured variable or a proportional electrical measured variable takes place, whereby the

electrical measurement principle is complete.

The test aerosol fluid stream TA continues to flow through the measuring channel 24 and passes through the saturation unit S, the test aerosol fluid stream TA being saturated with the vapor of a resource B (FIG. 1). The (saturated) test aerosol fluid flow TA then continues to flow through the measuring channel 24 and passes through the condensation unit K, in which the test aerosol fluid flow TA is cooled, so that the operating medium B condenses on the solid particles P. The test aerosol fluid flow TA then continues to flow with the condensate droplets and passes through the optical measuring cell OM, in which the optical measurement of the measurand takes place, which also completes the optical measuring principle. In the example according to FIG. 3d, all sequential process steps of the electrical measuring principle are carried out first and then all sequential

Process steps of the optical measuring principle carried out.

Of course, the reverse variant would also be conceivable. In principle, this embodiment essentially corresponds to a sequential use of the two separate measuring devices according to FIG. 1 and FIG. By integrating both measuring devices in one device, however, a device 23 can be created that is significantly simpler in construction compared to two separate measuring devices

and is in use.

A further advantageous embodiment of the invention is explained below with reference to FIG. It is provided that at least one mixing unit M is arranged in the measuring section MA of the device 23, which is designed to mix the test aerosol fluid flow TA with a carrier aerosol fluid flow TRA to form a mixed fluid flow MF. At least one measuring device component 27, 28 of the optical and/or the electrical measuring device is arranged in the measuring section MA of the device 23 in such a way that the respective method step of the optical and/or the electrical measuring principle can be carried out in the carrier aerosol fluid flow TRA before mixing in the mixing unit M . Furthermore, at least one measuring device components 27, 28 of the electrical and / or

the optical measuring device is arranged in the measuring section MA of the device 23 in such a way that

13/53”

15

20

25

30

35

AV-4223AT

the respective process step of the electrical and/or the optical measuring principle in

Test aerosol fluid stream TA can be carried out in the mixing unit M before mixing.

At least one measuring device component 27 of the optical measuring device and at least one measuring device component 28 of the electrical measuring device are arranged in the measuring section MA of the device 23 such that the respective method step of the optical measuring principle and the respective method step of the electrical measuring principle can be carried out in the mixed fluid flow MF after the mixing unit M . These can preferably in turn be carried out at least partially in parallel on the mixed fluid flow MF, as has already been explained with reference to FIG. 3a. A gas that is as particle-free as possible should be used as the carrier aerosol fluid flow TRA, for example filtered air, nitrogen (N2) or an inert gas. In order to obtain air that is as particle-free as possible, room air can, for example, be passed through a suitable filter in order to remove the particles it contains. A well-known HEPA filter (High-Efficiency Particulate Air-Filter) can be used as a filter, for example. The carrier aerosol fluid flow TRA is preferably fed to the device 23 via a suitable connection 29 . After carrying out the corresponding method step in the at least one measuring device component 27, 28, the carrier aerosol fluid flow TRA via a

suitable feed channel 30 of the mixing unit M are fed.

A suitable "passive" device can be provided as the mixing unit M, for example, in which the fluid flows are mixed without external energy, e.g. by turbulence. A suitable "active" device can also be provided as the mixing unit M, for example, in which the fluid flows are mixed by means of external energy, e.g. by a driven mixing element. In the example shown according to FIG. 3e, the test aerosol fluid flow TA first flows via the measuring channel 24 to the charging unit L of the electrical measuring principle, in which the solid particles P are electrically charged. The charging takes place here with a fixed first, here positive, polarity, as indicated by the plus symbol. The (charged) test aerosol fluid stream TA then flows through

the measuring channel 24 and reaches the mixing unit M.

The carrier aerosol fluid flow TRA is fed to the device 23 via the connection 29 and is fed to the saturation unit S, in which the carrier aerosol fluid flow TRA is saturated with a suitable vapor, for example with a working medium vapor of a working medium B (FIG. 1). In addition, the carrier aerosol fluid stream TRA is electrically charged with a second, here negative, polarity, as indicated by the minus symbol in FIG. 3e. Charging can take place directly in the saturation unit S, but could also take place in a downstream (not shown) separate unit, for example an analog charging unit L as in the electrical measuring device. After the saturation unit

S (or the separate (charging) unit) flows the (saturated and negatively charged)

14 153”

15

AV-4223AT

Carrier aerosol fluid flow TRA through the feed channel 30 to the mixing unit M and is mixed there with the simultaneously supplied (positively charged) test aerosol fluid flow TA to form a mixed fluid flow MF. Due to the opposite polarity, the accumulation of saturated vapor of the carrier aerosol on the particles of the test aerosol fluid flow TA

be relieved.

The mixed fluid flow MF thus contains a mixture of positively charged solid particles P and negatively charged particles of the carrier aerosol fluid flow TRA. The mixed fluid stream MF optionally runs through a condensation unit K, as indicated by dashed lines, in which the mixed fluid stream MF is cooled, so that the operating medium B condenses on the solid particles P of the original test aerosol fluid stream TA. It can thereby be achieved that all condensate droplets have essentially the same size. The optical measurement of the measurand then takes place in the optical measuring cell OM and the electrical measurement of the measurand in the electrical measuring cell EM. This can be done sequentially, for example, or as in

3e shown (at least partially) in parallel.

Claims (18)

15 20 25 30 35 AV-4223 AT patent claims 1. A method for determining at least one measured variable of solid particles (P) in a test aerosol fluid flow (TA) that is passed through a measuring section (MA), characterized in that in the measuring section (MA) on the same test aerosol fluid flow (TA) at least one detection at least one measured variable according to an optical measuring principle and at least one detection of at least one measured variable is carried out using an electrical measuring principle. 2. The method according to claim 1, characterized in that at least a particle number and/or a particle number concentration and/or a particle mass and/or a particle size of the solid particles (P) is determined as a measured variable using the optical measuring principle and/or that using the electrical measuring principle at least one particle number and/or one particle number concentration and/or one particle mass and/or a particle size of the solid particles (P) is determined as a measured variable. 3. The method according to claim 1 or 2, characterized in that the optical measuring principle and the electrical measuring principle each comprise a plurality of sequential method steps (L, EM; S, K, OM). 4. The method according to claim 3, characterized in that at least one method step (OM) of the optical measuring principle and one method step (EM) of the electrical measuring principle are carried out at least partially in parallel on the test aerosol fluid flow (TA) be performed. 5. The method according to claim 3 or 4, characterized in that the method steps (S, K, OM) of the optical measuring principle and the method steps (L, EM) of the electrical measuring principle are carried out at least partially in alternation. 6. The method according to claim 3, characterized in that first all method steps (S, K, OM) of the optical measuring principle are carried out and then all method steps (L, EM) of the electrical measuring principle are carried out or vice versa. 7. The method according to any one of claims 1 to 6, characterized in that the measuring section (MA) is supplied with a carrier aerosol fluid flow (TRA) which is mixed with the test aerosol fluid flow (TA) to form a mixed fluid flow (MF), at least one method step (S) of the optical and/or electrical measuring principle being carried out in the carrier aerosol fluid stream (TRA) before mixing (M) and at least one method step (L) of the electrical measuring principle being carried out in the test aerosol fluid stream (TA) before mixing (M). and / or optical measurement principle is carried out and that in the mixed fluid flow (MF) after 16/53” 15 20 25 30 35 AV-4223AT the mixing (M) at least one method step (OM) of the optical measuring principle and at least one method step of the electrical measurement principle (EM) is carried out. 8. The method according to any one of claims 1 to 7, characterized in that a condensation particle count is used as the optical measuring principle and / or that a diffusion charge measurement is used as the electrical measurement principle. 9. The method according to claim 8, characterized in that the condensation particle count comprises at least the following method steps: - saturating (S) an aerosol fluid stream with a working medium vapor of a working medium (B), - Cooling of an aerosol fluid stream for condensing (K) the operating medium (B) on the solid particles contained (P), - Optical measurement (OM) of the measurand in an aerosol fluid flow, preferably by means of scattered light measurement and/or that the diffusion charge measurement comprises at least the following method steps: - Electrical, preferably pulsed, charging (L) of an aerosol fluid stream, in particular of the solid particles (P) contained therein, - Electrical measurement (EM) of the measurand or one proportional to the measurand electrical quantity in an aerosol fluid stream. 10. Device (23) for determining at least one measured variable of solid particles (P) in a test aerosol fluid flow (TA), a measuring section (MA) for determining the at least one measured variable in the test aerosol fluid flow (TA) being provided in the device, characterized in that at least one optical measuring device (1) is arranged in the measuring section (MA), which is designed to determine at least one measured variable of the solid particles (P) of the test aerosol fluid flow according to an optical measuring principle, and that in the measuring section (MA) additionally at least one electrical measuring device (13) is provided, which is designed to at least one measured variable of the solid particles (P) on the same test aerosol fluid flow (TA) after an electrical to determine the measuring principle. 11. Device (23) according to claim 10, characterized in that the optical measuring device (1) is designed to determine a particle number and/or a particle number concentration and/or a particle mass and/or a particle size of the solid particles (P) as a measured variable and/or that and the electrical measuring device (13) is designed to measure a particle number and/or a particle number concentration and/or a particle mass and/or a particle size Determine solid particles (P). 17158” 15 20 25 30 35 AV-4223AT 12. Device (23) according to claim 10 or 11, characterized in that the optical measuring principle comprises a plurality of sequential method steps (S, K, OM), wherein at least one measuring device component ( 27) is provided and / or that the electrical measurement principle comprises a plurality of sequential method steps (L, EM), wherein to carry out each method step (L, EM) of the electrical measurement principle at least a measuring device component (28) is provided. 13. Device (23) according to claim 12, characterized in that at least one measuring device component (27) of the optical measuring device (1) and at least one measuring device component (28) of the electrical measuring device (13) are arranged on the device (23) (23). are that the respective process step (OM) of the optical measurement process and the respective process step (EM) of the electrical measurement process are carried out at least partially in parallel on the same test aerosol fluid flow (TA) are feasible. 14. Device (23) according to claim 12 or 13, characterized in that at least one measuring device component (27) of the optical measuring device (1) and at least one measuring device component (28) of the electrical measuring device (13) are arranged on the device (23). that the process steps (S, K, OM) of the optical measuring principle and the process steps (L, EM) of the electrical measuring principle can be carried out at least partially in alternation. 15. Device (23) according to claim 12, characterized in that the measuring device components (27) of the optical measuring device (1) and the measuring device components (28) of the electrical measuring device (13) are arranged on the device (23) such that first all Process steps (S, K, OM) of the optical measuring principle can be carried out and then all process steps (L, EM) of the electrical measuring principle can be carried out or vice versa. 16. Device (23) according to one of claims 10 to 15, characterized in that in the device (23) at least one mixing unit (M) is arranged, which is designed to mix the test aerosol fluid flow (TA) with a carrier aerosol fluid flow to mix to form a mixed fluid flow (MF), wherein at least one measuring device component (27, 28) of the optical and/or the electrical measuring device (1, 13) is arranged in the device (23) in such a way that the respective method step (S) of the optical and/or electrical measuring principle in the carrier aerosol fluid stream (TRA) prior to mixing in the mixing unit (M) and at least one measuring device component (27, 28) of the electrical and/or the optical measuring device (1, 13) is arranged in the device (23) that the 15 20 25 AV-4223AT respective method step (L) of the electrical and/or optical measuring principle can be carried out in the test aerosol fluid stream (TA) before mixing in the mixing unit (M) and that at least one measuring device component (27) of the optical measuring device (1) and at least one measuring device component ( 28) of the electrical measuring device (13) are arranged in the device (23) in such a way that the respective method step (OM) of the optical measuring principle and the respective method step (EM) of the electrical measuring principle in the mixed fluid flow (MF) after the mixing unit (M ) are feasible, preferably at least partially parallel to the mixed fluid flow (MF). 17. Device (23) according to one of claims 10 to 15, characterized in that a condensation particle counter is provided as the optical measuring device (1) and/or that the electrical measuring device (13) is a Diffusion charge measuring device is used. 18. Device (23) according to one of claims 10 to 17, characterized in that the condensation particle counter comprises at least the following measuring device components: - at least one saturation unit (S), - at least one condensation unit (K), - At least one optical measuring cell (OM) for the optical measurement of the measurand, preferably a scattered light measuring device and/or that the diffusion charging measuring device comprises at least the following measuring device components: - at least one charging unit (L) for the preferably pulsed, electrical charging of an aerosol fluid flow, in particular the solid particles (P) contained therein, - At least one electrical measuring cell (EM) for electrically measuring the measurand or an electrical measurement variable proportional to the measurement variable. 19/53”