WO2019120821A1

WO2019120821A1 - System for preparing an aerosol

Info

Publication number: WO2019120821A1
Application number: PCT/EP2018/081790
Authority: WO
Inventors: Thomas Maier
Original assignee: Horiba Europe Gmbh
Priority date: 2017-12-21
Filing date: 2018-11-19
Publication date: 2019-06-27
Also published as: DE102017130981B3

Abstract

A system for preparing an aerosol has a particle generator (7) for generating a particle flow and a dilution system (8) for diluting the particle flow with dilution air. Downstream of the dilution system (8) there is provided an outlet (11) and a particle preparation device (24). Part of the particle flow supplied to the dilution system (8) can be guided to the outlet (11), while another part of the particle flow supplied to the dilution system (8) can be guided to the particle preparation device (24). A pressure gradient exists in the dilution system (8), in order to convey the particle flow. In addition, a controlled proportional valve (26, 27) is provided between the dilution system (8) and the outlet (11), and serves to set with precision the pressure ratios in the dilution system (8).

Description

System for providing an aerosol

The invention relates to a system for providing an aerosol.

For emission monitoring of engines and vehicles, it is legal requirement that the exhaust gases on a test bench or even under real conditions, e.g. on the road, and to investigate their composition in detail. Here, in addition to a variety of pollutant levels especially particulate matter of particular interest. The fine dust particles, for example, nanoparticles, can penetrate deeply into the lungs via the respiration and lead to considerable health impairments. In addition to the particles emitted by engines, particle emissions from other components, such as brake and tire abrasion, can be regulated in a similar manner in the future.

For detecting the particles, corresponding particle measuring devices are known, which are used in test stands or measuring systems equipped therefor. Particu- larly due to legal regulations, the particle measuring instruments must be regularly maintained, checked and calibrated in order to permanently ensure the required accuracy of the measurements. Examples of such legal regulations are, for example, UNECE Regulation No. 83, Rev. 5, Series 05 or UNECE Regulation No. 49, Rev. 4, Series 05 or the Global Technical Regulation (GTR) no. 15 etc. These regulations require eg a regular review of the systems every 12 months.

For the regularly required checking of particle measuring devices (test object), it is known to provide a particle generator which generates particles in a mass flow and transfers them to a carrier medium (air, nitrogen, etc.). This so-called "aerosol" is measured in parallel with respect to the particle characteristic to be tested (particle concentration, particle number, particle mass, opacity, etc.) by a reference meter and also supplied to the device to be tested Messge. By comparing the measurement results of the reference measuring device and the device to be tested, the device to be tested can be used, for example, as a reference device. nachjus be.

For the provision of the aerosol, it is usually necessary to dilute the aerosol generated by the particle generator. This can be changing external conditions, eg air pressure or ambient temperature, but not exactly reproducible operator influences (adjustment of valves, flows, etc.) lead to a change in the dilution effect and thus a change in the Ae rosol quality. The changing conditions can lead in particular to the fact that the aerosol to be provided by the system or a component in the system (eg classifier, reference measuring device) has variable and therefore no longer constant or reproducible properties, which is the result of the following validation or calibration of the actual particle measuring devices he sword.

Although, due to the environmental influences changing measured values can often be corrected by appropriate correction calculations. An influence on the particle properties as well as on the working behavior of the relevant components, such as the particle generator, a classifier (hereinafter also referred to as classifier or classifier) or a reference particle measuring device, can still be maintained to some extent.

The invention has for its object to provide a system for providing an Ae rosols, in which (fully) automatically precise, defined and reproducible bare conditions for the generation and processing (dilution, Classifizie tion, etc.) of a suitable aerosol or particle flow can be provided.

The object is achieved by a system for providing an aerosol with the features of claim 1. Advantageous embodiments can be found in the dependent claims.

The invention relates to a system for providing an aerosol, comprising a particle generator for generating a particle flow, a dilution system arranged downstream of the particle generator for diluting the particle flow with dilution air, an outlet downstream of the dilution system (for discarding the particle) in a fume hood) and with a particle supply device provided downstream of the dilution system (to provide the Aero sol to be used). A portion of the dilution system supplied particle flow is feasible to the outlet, while another part of the particle flow to Parti kel-providing device is feasible. Furthermore, a Druckmesseinrich device is provided for measuring an actual value for the pressure at least egg ner point in the dilution system. In the dilution system there is a pressure gradient, wherein between the United dilution system and the outlet, a controllable or proportional valve is arranged. In addition, a control device is provided for setting the proportional valve A in dependence on the measured by the Druckmessein direction pressure-actual value and a predetermined pressure setpoint.

The dilution system is thus equipped with a device for detecting the pressure in the dilution system and a control device (Regelschlei fe / control unit) with a pressure as a setpoint (pressure setpoint), the detected pressure as the actual value (pressure feedback) and the proportional valve as a manipulated variable. This design allows decoupling from the rest of the environment. The pressure in the dilution system can be adjusted independently of changing environmental conditions.

The particle generator produces an aerosol which, in the present system, can subsequently be diluted in a completely controlled manner with respect to its pressures and flows. The dilution can - as will be explained later - one or more stages.

The particle generator is known per se in various embodiments and serves to produce particles in a polydisperse aerosol with a certain particle size distribution. The present system, because of its properties, is capable of cooperating with most of these popular particle generators, e.g. Within its design limits, to provide (regulate) any required pressures and pressure gradients for the removal of the particles towards the dilution system (even with variations in the aerosol flow).

Thus, in the system, the particle flow generated by the particle generator is passed through the dilution system. Part of the diluted and conditioned by the dilution system in the desired manner and conditioned particle flow is passed to the particle supply device, through which the particle flow its original purpose, for example, a test bed or ver to be examined particle measuring instruments can be performed.

Another part of the particle flow can be led to the outlet. The particle flow is thus determined by the particulate matter coming from the particle generator. River branched off. Optionally, the particle flow may already have been (partially) diluted in the dilution system.

Due to the consistently completed design of the particle-guiding system (in particular the controlled proportional valves) and by the control loops, it is possible to (automatically) adjust and regulate the conditions in the dilution system in a desired manner. In particular, it is possible to always define the pressure conditions in the dilution system at a desired level (pressure set point) and to keep them constant, regardless of the ambient conditions such as ambient air pressure, ambient temperature, air humidity, etc. Any location-related, but also changing environmental influences can be achieved compensate by the regulation and thus by regulating the flow of particles to the outlet and decoupling from the environment, as well as changing (interference) influences by components in the system.

The system allows the provision and dilution of an aerosol or a particle-free gas flow under precisely defined conditions, with an influence due to environmental conditions (installation site, weather, air pressure, etc.) and other (interference) influences excluded or at least uplifting Lich can be reduced ,

There is a pressure gradient in the dilution system. This means that the pressure gradient exists in particular between the inlet of the dilution system and a point of the dilution system located downstream of the inlet and thus drives the gas or aerosol flow. Downstream sites are in particular the connections to the outlet or the particle-providing device.

With the aid of the pressure gradient it is possible to maintain the flow of the particle flow through the dilution system or even to control the flow / flow rates within the controllable pressure levels.

The pressure gradient can be effected, for example, by a pressure sink between the dilution system and the outlet. The pressure sink creates a negative pressure that acts on the dilution system and thus causes the particle flow from the particle generator through the dilution system. For example, between the dilution system with the corresponding proportional valve and the outlet from the system, a pump can be arranged which generated pressure and applied to the dilution system. In this way, a mass flow is generated by the dilution system.

The generated by the pump negative pressure or negative pressure can in conjunction with one or more other proportional valves and a suitable control and optionally volumetric flow meters or mass flow meters always the same pressure and thus equal conditions for the dependent of the suppression components (eg control of upstream lying Ver dünnungsstufen) allow.

The output of the pump can be routed to the outlet in the environment or in an ex-train.

The pump may be used, for example, as a vacuum pump, in particular e.g. be designed as a rotary vane pump.

It is also possible to apply an overpressure (increased pressure) upstream from the dilution system, in particular at the particle generator, which then acts at the inlet of the dilution system, effects the pressure gradient and generates the mass flow through the dilution system.

Particle flow inside the dilution system is split at a suitable location so that part of the flow of particles flows to the particle delivery device and another part to the outlet.

The system can thus be completely decoupled from the environment. Only at the upstream particle generator on the one hand and on the downstream lie lowing outlet on the other hand may exist a connection to the environment. By contrast, the area of the dilution system is completely decoupled from the environment, so that environmental influences have no effect on the dilution effect inside the dilution system or on all components integrated in the system or coupled to the system (particle generator, classifier, mass flow meter, etc . ) to have.

The dilution stages are connected to ambient components exclusively by controlled manipulated variables (eg the proportional valves), which are regulated with corre sponding setpoint specification and actual value measurement (means for detecting the pressure) and a control loop. This allows a conse quente, decoupled from the environment and independent adjustment of the pressures within each dilution level (automatic, defined, precise, stable).

The control means controlling the pressures in the dilution system by means of the proportional valve (s) may also be part of a higher level control, e.g. a test bench control or similar his. In the control device, the respective desired values for the pressures can also be adjustable or stored.

The dilution can thus be done automatically under desired and precisely defini th and reproducible conditions and in particular independent of variable external conditions, such as ambient temperature, humidity, air pressure, site of the devices, etc., be. The multiplicity of error influences on the dilution and all components can thus be reduced.

The dilution system may have a first dilution step and a second dilution step downstream of the first dilution step. It is also readily possible to provide further dilution stages in the dilution system.

The first dilution stage may be connected to the outlet via a first regulated proportional valve, while the second dilution stage may be connected to the outlet via a second regulated proportional valve. In this sense, each of the dilution levels provided in the dilution stage may have its own regulated proportional valve leading to the outlet. Likewise, each of the dilution stages may have a unit for detecting the pressure in the dilution system and a control loop.

In particular, in the first dilution stage, a first Druckmesseinrich device may be provided for measuring an actual value for the pressure at least one point in the first dilution stage. Furthermore, in the second Ver dünnungsstufe a second pressure measuring device may be provided, for measuring an actual value for the pressure at least one point in the second dilution stage.

In addition, the regulating device can be designed to set the respective first and second controlled proportional valve as a function of the actual pressure values measured by the respective pressure measuring devices and the respective predetermined desired pressure values. With the help of the individual proportions associated with the respective dilution levels tional valves and regulations so that the pressure conditions in the interior of the respective dilution stage can be adjusted or adjusted conditions precisely and independently of the ambient conditions.

Regardless of whether a single-stage dilution or a multi-stage, for example, two-stage dilution, should be made, the volumetric flows and the pressure levels of these rivers are regulated so that, for example, it can be achieved ratios, the defined constant standard conditions corre chen (usually 101, 3 kPa - even at lower / different ambient pressures at the place of testing). Likewise, it is thus possible to achieve arbitrary pressure levels or to test a larger pressure range (e.g., stepwise).

The thus defined, to be provided aerosol or the particle-free gas flow can be provided in this way consistently for any measurement tasks, for example, for the validation or calibration of a particle measuring device, without changing the properties due to variable Umweltsein rivers. Also can thus conditions are generated at the provision device conditions, which are otherwise not representable for the DUT at the place of testing.

Irrespective of different flows provided by the aerosol source (particle generator) or different flows influenced by the devices to be tested or other components, the desired (equal) pressure in the respective dilution stage is always adjusted and any changes and disturbances corrected. Thus, there are always defi ned, independent of the environment and other test conditions pressure conditions for the particle generator and the classifier, more accurate keitsrelevante components in the system and the DUT and the reference.

In the first dilution stage, a pressure-controlled, environmentally-sealed dilution may be performed that is not subject to ambient pressure. Independently of different flows provided by the aerosol source, the same pressure is thus always regulated in the dilution stage. This can be achieved always defined, separated from the environment and other test conditions pressure conditions. Also in the second dilution stage, a pressure-controlled, completed by the surrounding environment dilution can take place, so that correspondingly defined, separated from the environment and other test conditions Druckver ratios are achieved.

Since the pressures in the two dilution stages can thus be regulated independently of the ambient conditions, it is also possible to control the flow between these stages, for example also by means of an interposed particle classifier (eg a DMA - Differential Mobility Analyzer), to actively regulate the pressure difference between the two dilution stages, so that the thus adjusting flow reaches the desired value.

Thus, between the first dilution stage and the second dilution stage, a classifier can be arranged for classifying the particles in the particle flow. The classifier may, for example, achieve a particle size classification or size selection. Corresponding devices are known, for example a DMA. This makes it possible to eliminate a monodisperse Ae rosol with a desired particle diameter from the aerosol generated by the particle generator. Depending on the equipment of the system, it is thus possible to obtain a model aerosol with particles of defined size (classifier) and with a set concentration (dilution) downstream of the dilution system.

The pressures in the two dilution stages can be regulated individually. In this way, the pressure gradient between the two dilution stages can be adjusted. For example, in the first dilution stage, a pressure value of 102 kPa can be set while in the second dilution stage a value of 101 kPa is set. Likewise, the first dilution stage can be set to a pressure value of 100 kPa, while the pressure in the second dilution stage can reach a higher value, for example 101 kPa, wherein the pressure increase can be assisted by a subsequently explained pump.

Between the first dilution stage and the second dilution stage, a pump, in particular a Venturi pump can be provided. In particular, the venturi pump is capable of producing an additional positive pressure gradient between the first dilution step and the second dilution step. This also makes it possible, for example, to increase the pressure from one to the next dilution stage. For example, in the first dilution pressure level of 90 kPa are set, while in the second Ver dilution stage, an increased pressure in a variable range of 90-1 10 kPa is needed. This (variable) pressure increase can be effected by the Venturi pump.

At the same time, the Venturi pump can lead to pre-dilution because the ambient or dilution air supplied to it enters the gas flow.

In particular, the venturi pump may be provided between the classifier and the second dilution stage. The additional positive pressure gradient generated by the Venturi pump allows the flow through the classifier (DMA) to be adjusted.

It may be provided a control device for regulating a gas flow serving as a set value between the first dilution stage and the second dilution stage. In this case, a gas flow measuring device may be provided between the first dilution stage and the second dilution stage, for measurement of an actual value for the gas flow which can be fed to the control means. By the control device, the pump power of the Venturi pump can be adjusted so as to influence the actual value such that it approaches the desired value.

Thus, to control the flow through the classifier or the flow between the two dilution stages (set point), the measured value of the gas flow measuring device (for example volumetric flow meter or mass flow meter), e.g. may be placed in the classifier or at another suitable location between the two dilution stages. The pumping capacity of the Venturi pump, which is used, for example, as an actuating variable. can be adjustable by a controlled proportional valve. The proportional valve may be provided in a surrounding air supply line for supplying ambient air for driving the venturi pump, as will be explained later. By adjusting the pumping power of the Venturi pump, it is thus possible to adjust the gas flow between the two dilution stages in the desired manner and in particular special effect to cause an increase in pressure. By selecting the desired pressure values, a defined pressure gradient can be established between the dilution stages.

By arranging the classifier (also referred to as classifier or classifier) and the venturi pump between the first dilution It is thus possible, during operation and the second dilution stage, that during operation the settings for the first dilution stage remain unchanged (and thus the conditions for particle generation, dilution and classification, for example), while the settings (and thus, for example, the pressures) for the first dilution stage second dilution stage defined can be changed (and thus, for example, the conditions of the test specimen).

The venturi pump can be particularly advantageous because it does not change the aerosol flow and in particular no particles can be deposited.

An ambient air supply may be provided, with an ambient air supply leading to the second dilution stage, for supplying ambient air to the second dilution stage. With the help of the ambient air serving as dilution air, the desired dilution effect can be achieved in the second dilution stage. Analog can also be provided for the first Ver dünnungsstufe an ambient air supply.

The term serving as dilution air "ambient air" is to be understood in this context to broad. The ambient air may be air from the environment, e.g. is supplied as compressed air. However, it is also possible to use e.g. Nitrogen serve as "ambient air".

To operate the Venturi pump, it may be particularly suitable that a wide re ambient air supply line is provided for supplying ambient air for operating the Venturi pump.

In the ambient air supply line leading to the venturi pump, a mass flow measuring device and / or a proportional valve may be provided in order to adjust the air flow to the venturi pump and thus its pumping action or pumping power.

Also in the leading to the second dilution stage ambient air supply can be a pre-see mass flow meter and a proportional valve to adjust the flow of the supplied ambient air.

The ambient air supply for the Venturi pump may branch off from the ambient air supply line for the second dilution stage at a location downstream of its mass flow meter, the branch leading to upstream of may be located in the ambient air supply line for the second dilution stage NEN proportional valve.

This arrangement allows the ambient air to be supplied via the first ambient air supply line. Part of the ambient air is diverted with the aid of the second ambient air supply line after the measurement (or also adjustment) of the volume flow and fed to the Venturi pump to these ben to trei. The other part is fed via the first ambient air supply line directly to the second dilution stage as dilution air. The ambient air part, which was supplied to operate the Venturi pump, passes after passing through the Venturi pump also in the second dilution stage, where it reunites with the other ambient air part, which was supplied via the first ambient air supply line. In sum, therefore, the originally supplied ambient air remains the same, since the first divided dilution air streams are brought together again in the second dilution stage. This (total) dilution air flow can be determined by the mass flow measuring device previously arranged in the first ambient air feed line. Thus, the overall dilution air flow will always remain constant through this configuration - for example, even during changes in the flow into the venturi pump (e.g., during the above-described active automatic control of flow through the classifier by venturi pumping power). A change in the dilution factor in the second dilution step is thereby avoided.

Between the venturi pump and the second dilution stage and / or between the classifier and the second dilution stage, a bypass to the outlet may be provided. In particular, the bypass allows a portion of the supplied aerosol stream to be removed and discarded via the outlet. This can be adjusted by a proportional valve in the bypass. This is especially helpful if the supplied aerosol stream is hochkon centered and in the second dilution stage, a very strong dilution air flow would have to be achieved in order to achieve the desired particle concentration at the end. By discharging a portion of the highly concentrated aerosol stream through the bypass, the remaining aerosol stream passing into the second dilution stage can be more dilute, even if the dilution air supplied to the second dilution stage is not to be increased in volume.

Through the bypass, an influence of the mass flow in the second dilution stage, since a part of the originally supplied mass flow over the outlet is discarded. Therefore, it may be useful for clarification of the measurement, that in the bypass also a mass flow measuring device are provided to compensate for the mass flow in the second dilution stage on the basis of their measured value.

For example, there is often a requirement on a test rig to vary the particle concentration for a linearity test of the test specimens (of the equipment under test), which is usually realized by greatly increasing the dilution air flow and associated high dilution of the particulate stream (and thus actually unwanted strong changes, for example, the pressure and turbulence conditions in the dilution). In this case with bypass, to reduce the particle concentration, a corresponding portion of the aerosol downstream from the venturi pump (or classifier) and before the second dilution stage can be branched off and discarded via the bypass.

The particle providing means provided downstream of the second dilution stage may comprise a particle supply line for guiding the aerosol stream leaving the second dilution stage to a device to be supplied with the aerosol stream. The device may, for example, be a particle meter to be tested. The particle supply line can in particular be coupled to a connecting device, which will be explained below, to which the device to be tested can be connected.

The system for providing an aerosol may be coupled to a device that can be connected to the system to be tested, wherein a connection device may be provided for connecting the device to be tested.

The device under test (for example particle measuring systems in test benches) can be connected to the connecting device in a simple manner. The Anschlußussein direction can thus provide the necessary or useful connection options to connect the device under test to the system can. Thereby, e.g. Hose couplings, connectors, Schraubverbindun gene, bayonet joints be present. In addition, the corresponding lines are provided to carry out the mass flows.

The connection device can have a plurality of lines to which the device to be tested can be connected. The entire system may be in the form of a mobile unit. In particular special unit can be accommodated in a frame, frame or cabinet, which is also movable or, for example, on wheels. This allows all the components in the rack or cabinet housed who the, so that the system can also be performed to various devices and equipment to be tested. It is therefore not necessary to take each consuming up and dismantling measures to fen various devices to be tested ver.

Known dilution systems generally have an unregulated, closed scheme or an open, overflowing scheme. With closed systems, special care must be taken by means of manual adjustment that all volume flows match one another, so that a balance between the incoming and outgoing mass flows can be achieved. The currents are partly manually adjusted in order to avoid mutual interference. Even small changes in the components, for example due to a pump that does not deliver uniform pressure, can have a negative effect on the entire system and thus affect the accuracy of the dilution. These changes usually need to be manually detected and corrected.

In contrast, it is provided in the system according to the invention that all parameters are measured automatically and subsequently adjusted automatically.

Overflow systems are open towards an outlet or the atmosphere. However, since the environmental conditions are variable, the feedback to the gas flows in the system is the same, which can also affect the accuracy.

In the system according to the invention, said problems can be solved by (its design with) a combination of venturi pumps, mass flow meters, proportional valves and e.g. an end provided vacuum pump and pressure measurement and control loops are avoided, so that it is possible to provide Ae rosol stable and independent of the external conditions and other disturbances.

These and other advantages and features will be described below with reference to playing with the aid of the accompanying figures. Show it 1 shows a schematic overview of a system for validating aerosol and flow measuring devices, with a system according to the invention for providing an aerosol; and

Fig. 2 is a more detailed partial view of the system for providing ei nes aerosol of Fig. 1st

Fig. 1 shows a calibration and validation system 1 for validating aerosol and flow meters in a connectable to the system to be tested device. In the calibration and validation system 1, e.g. the present system for providing an aerosol can be used, which is explained below with reference to FIG. 2.

Most components of the system 1 are housed in a tempered cabinet 2. For example, the cabinet 2 may be mounted on rollers and easily movable in the manner to move it to the desired location for the respective calibration or validation operations.

At a readily accessible to the cabinet 2 connection device 3, a device to be tested 4 can be connected. For this purpose, one or more lines may be provided on the device 3 Anschlußussein, which - in the simplest case - have plug-in couplings, so that the corresponding line connections must be inserted only.

The device to be tested 4 is connected via the dargestell te by a symbolic box te connection device 3 with the system 1 in the cabinet 2.

If necessary, further devices 5, in particular special devices to be tested 4 can be connected to the connection device 3.

Furthermore, an overall system controlling controller 6 is provided. The controller 6 may on the one hand be provided on the device 4 to be tested. But it can also be part of the system 1 and in this case also be housed in or on the cabinet 2.

The controller 6 is able to drive all components of the system 1, for example, to automatically perform various modes of operation. The operating modes may be, for example, an aerosol validation mode and act a flow validation mode. Switching the various operating modes can also be carried out automatically with the aid of the control 6. It is thus possible, after the only time connecting the device under test 4 with the system 1 via the connection device 3 to perform all calibration and Validiervor courses in one go automatically without an operator has to make any switching or even conversion measures in between , The various steps are performed by the controller 6 after each other without the need for assistance from an operator.

In particular, the controller 6 may also be designed to perform the specific measuring and control tasks that occur in the system according to the invention for providing an aerosol.

The system 1 and the essential components are explained below:

A per se known particle generator 7 generates a polydispersed aerosol with a certain particle size distribution. Due to a pressure gradient in the system 1, which can be generated, for example, by one or more pumps not shown in FIG. 1, the particle aerosol flow flows into a dilution system 8 in which the particle flow can be conditioned and diluted. For this purpose the dilution system 8 is supplied with dilution air 9 from the outside. In addition, a classifying device 10 can be provided which classifies the particles more precisely in order to be able to separate out a monodisperse aerosol having the desired particle diameter. The classifier 10 may be, for example, a per se known differential mobility analyzer (DMA) for particle size classification and size selection. The desired particle selection can be carried out by means of an electrostatic classification.

In the dilution system 8, one or more, in particular two Ver can be provided dünnungsstufen. The design takes place as needed for concentration adjustment and flux increase.

The invention relates to the system for providing the aerosol and thus in particular the design and the interaction of the particle generator 7 and the dilution system 8. This system will be explained in more detail later with reference to FIG. 2.

Downstream of the dilution system 8, part of the mass flow is led to an outlet 11, while another part (reference 24) is used as a model aerosol to a ball valve switching device 12 (also: ball valve unit) ge leads. The ball valve switching device 12 is part of a Umschalteinrich device for switching the mass flow as a function of the desired mode.

The ball valve switching device 12 makes it possible to connect a reference particle measuring device 13, which in the example shown has two reference particle measuring devices, a first reference particle measuring device 14 and a second reference particle measuring device 15. The mass flow conducted to the reference particle measuring devices 14, 15 can be diverted through a flow divider 13a, not shown.

The reference particle measuring devices 14, 15 may, for example, be a CPC

Allow calibration (Condensation Particle Counter), which is compared using the condensation core counters, the count rates of the corresponding connected device to be tested 4 compared to the reference particle measuring devices 14, 15.

The other part of the model aerosol, which is not guided to the reference Teilchenmesseinrich device 13, passes through the connection device 3 to the test device 4 and there, for example. to the particle meter inside the device to be tested 4. By comparing the counts of the reference particle measuring devices 14, 15 on the one hand and the device to be tested 4 or a particle sensor therein the latter can be validated or calibrated. Thus, either the instrument will be validated or calibrated against the reference particle gauges 14, 15 alone in the device under test 4, or the particle dilution and particle losses in the device 4 under test will be measured as a whole or in detail.

Other measuring methods are also possible, for example a VPR calibration (Volatile Particle Remover) for detecting particle losses via components in the system to be tested via corresponding count rates at the input and output of the component (change through ball valve changeover device).

The first mode described above with its various tests may also be referred to as aerosol validation mode.

For (automatically) performing the second valid mode flow validation mode, the controller 6 appropriately switches the ball valve switching device 12 so that connection of one port of the device under test to a solenoid valve unit 16 is provided. In addition, direct gas paths between device to be tested and solenoid valve unit may be provided. The solenoid valve unit 16 has solenoid valves which can open and close different flow paths, depending on the control by the controller 6. The solenoid valve unit 16 is coupled in terms of flow with a reference mass flow measuring device 17 serving as a reference gas flow measuring device, in which one or more later described Re reference mass flow meters are provided.

The guided in the flow validation mode by the reference Massenflussmessein direction 17 gas or mass flow is there precisely measured and closing to a - through the valve units (the test system and the tes tendem device) - serially connected flow measuring component in testing device 4 out where also takes place a measurement of this mass flow. In this way, the mass flow device provided in the device 4 to be tested and serving as a gas flow measuring device can be validated or calibrated by comparison with the results of the reference mass flow measuring device 17. Thus, a selection or all of the flow measurement components in the device to be scanned can be sequentially checked.

The components shown in Fig. 1 for providing a suitable aerosol, in particular the particle generator 7, the dilution system 8 and, where appropriate, the classifier 10 are part of a system for providing an aerosol, which will be explained in detail with reference to FIG.

It should be noted that the use of the system according to the invention for providing an aerosol in the calibration or validation system shown in FIG. 1 represents only one example of an application. The system for providing an aerosol can also be readily used in other systems where an aerosol of defined, consistent quality and consistent properties is required. The use of the system of FIG. 2 in a calibration or validation system according to FIG. 1 thus serves only to explain, but not to limit the usability.

Fig. 2 shows a more detailed structure of the verwen in the system of Fig. 1 Deten system for providing an aerosol.

The particle flow from the particle generator 7 passes into a first dilution stage 18, where ambient air as dilution air via a particle conditioner 19th is supplied. For better illustration, the dilution air flow is shown in FIG. 2 by surrounded arrows, while the aerosol flow is symbolized by solid black arrows.

Downstream of the first dilution stage 18, the classifying device 10 (optional) is provided, behind which a Venturi pump 20 for demand-based He testify a particular positive pressure gradient is provided in the dilution system 8.

Downstream of the venturi pump 20, a second dilution stage 21 is angeord net. The dilution system 8 thus has the first dilution stage 18, the classifier 10, the venturi pump 20 and the second dilution stage 21.

For generating an aerosol flow in the dilution system 8 and a pressure gradient necessary for this purpose, a pump 22, for example a vacuum pump, such as a rotary vane pump, is provided which conveys a mass flow to the outlet 11. The pump 22 has appropriate connections to the first dilution stage 18 and to the second dilution stage 21, as later erläu tert, but also to the bypass 21 -33 and optionally to another ambient air supply 28 (pump vacuum control).

In addition, further supplies of ambient air via a pressure reducer 23 and various mass flow meters (Mass Flow Meter - MFM) can be easily seen in order to monitor the respective mass flows can. Thus, a complete control of the mass or aerosol flows is possible, so that finally a fully defined and controlled model aerosol flow in a particle supply line 24 for further use (eg to the ball valve switching device 12 shown in Fig. 1 (ball valve unit)) promoted becomes. The model aerosol flow in the particle delivery line 24 may also be e.g. B. are conveyed directly to the connection device 3 (Fig. 1) and used there for further use.

The pump 22 is connected via a vacuum line 25 to the dilution system 8 and the dilution stages 18 and 21 in the dilution system 8. In particular, each dilution stage 18, 21 is connected via a proportional valve to the vacuum line 25, namely the first dilution stage 18 via a first controlled proportional valve 26 and the second dilution stage 21 via a second controlled proportional valve 27. For fine adjustment of the negative pressure or negative pressure in the Unterdrucklei device 25, an ambient air supply line 28 is also provided, in which a (gere geltes) ambient air proportional valve 29 is arranged.

By means of the controlled proportional valves 26, 27, 29 and not gezeig th in Figure 2, but each provided pressure measuring devices thus the individual nen mass flows and pressures can be very precisely influenced and controlled to adjust the properties of the aerosol stream in the desired manner.

For controlling the various proportional valves and thus for regulating the individual pressures, a regulating device may be provided, which may be e.g. also part of a higher level control, e.g. a test bench control or similar can be. As a control, therefore, e.g. also the controller 6 in FIG. 1. In the control device, the respective desired values for the pressures can also be adjustable or stored.

Upstream of the pump 22 may also be arranged a buffer tank 30 to compensate for pressure fluctuations due to the pump 22, if necessary.

Between the venturi pump 20 and the second dilution stage 21 is a by pass 31 to the vacuum line 25 is provided. In the bypass 31, a by-pass proportional valve 32 and a mass flow meter 33 is arranged. By means of the bypass 31, it is possible to discard a defined part of the aerosol stream, if a particularly high dilution in the second dilution stage 21 is to be achieved. The discarded part of the aerosol stream can be compensated again in the second dilution stage 21 by additional dilution air.

As already explained above, ambient air (dilution air) can be supplied via further feeds. For this purpose, a 21 to the second Ver Ver leading ambient air supply line 34 is provided, in which the pressure reducer 23 may be arranged. Downstream of the pressure reducer 23, a mass flow measuring device 35 may be provided.

The ambient air supply line 34 leads ambient air via a proportional valve 36 to the second dilution stage 21. From the leading to the second dilution stage 21 ambient air supply 34 branches off a further ambient air supply line 37, with a Massenflussmessein direction 38 and a proportional valve 39 from. This further ambient air duct 37 leads to the venturi pump 20 for directing airflow to the venturi pump 20, which drives the pumping action in the venturi pump 20 and in the venturi pump 20 with the aerosol flow from the classifier unit 10 mixes. In particular, the over the other ambient air supply 37 supplied dilution air used to operate the Venturi pump 20 who the.

The ambient air flow is then supplied via the leading to the second dilution stage 21 ambient air supply line 34. A portion of the ambient air flow is diverted via the leading to the Venturi pump 20 further ambient air supply line 37, used to operate the Venturi pump 20 and fed into the second dilution stage 21. The remaining part of the ambient air flow is performed via the ambient air supply line 34 directly into the second dilution stage 21, where the ambient air (partial) streams reunite, so that the determined by the mass flow meter 35 total amount of air remains unchanged.

Upstream of the proportional valve 36 and downstream of the diversion of the leading to the Venturi pump 20 ambient air supply line 37 may be provided in the leading to the second dilution stage 21 ambient air supply line 34, another, not shown in Fig. 2 mass flow measuring device.

Due to the different proportional valves, the pressure levels in the individual volume flows can be precisely adjusted. It is thus possible with the aid of the pump 22 and the ambient air proportional valve 29 to adjust the pressure level of the volume flow in the first dilution stage 18 with the aid of the first regulated proportional valve 26. The volume flow to the classifier 10 can thus be kept at a constant level, even if the volume flows from the particle generator 7 vary.

The coming of the classifier 10 aerosol is mixed in the Venturi pump 20 with dilution air from the ambient air supply lines 34, 37 ver. The volume flows of this ambient air supply are controlled by ent speaking volumetric flow meter (mass flow meter 38) and the proportional valve 39. The Venturi pump 20 therefore provides a precise and known volume flow with dilute aerosol to the second dilution stage 21, where a further dilution with additional dilution air (which is also controlled by mass flow meter and the proportional valve 36) takes place.

By controlling the Venturi pump 20, it is also possible to adjust the gas flow between the two dilution stages 18, 21 to a desired value. For this purpose, a gas flow measuring device, not shown in FIG. 2, can be provided between the two dilution stages 18, 21, which serves to detect an actual value. The desired value specified via a control device can then be achieved by changing the pumping power of the Venturi pump 20 by means of the controlled proportional valve 39.

A further reduction of the particle number or particle mass in the aerosol can be achieved by means of the bypass 31.

The pressure level in the second dilution stage 21 is regulated as a function of the incoming volume flows by means of the second proportional valve 27 and the ambient air proportional valve 29, so that a constant volume flow 24 can be supplied with the model aerosol.

Claims

claims

1 . System for providing an aerosol, with

a particle generator (7) for generating a particle flow;

a dilution system (8) arranged downstream of the particle generator (7) for diluting the particle flow with dilution air;

an outlet (11) provided downstream of the dilution system (8); and with

a particle delivery device (24) provided downstream of the dilution system (8);

in which

a portion of the dilution system (8) supplied particle flow to the outlet (1 1) is feasible and another part of the dilution system (8) supplied particle flow to the particle supply device (24) is feasible cash;

a pressure measuring device is provided for measuring an actual value for the pressure at at least one point in the dilution system (8);

a regulated proportional valve (26, 27) is provided between the dilution system (8) and the outlet (11); and where

a control device is provided for adjusting the proportional valve (26, 27) in dependence on the pressure measured by the pressure measuring device senen actual pressure value and a predetermined pressure setpoint.

2. System according to claim 1, wherein

the dilution system (8) has a first dilution stage (18) and a second dilution stage (21) downstream of the first dilution stage (18); the first dilution stage (18) is connected to the outlet (11) via a first regulated proportional valve (26); and where

the second dilution stage (21) is connected to the outlet (11) via a second regulated proportional valve (27).

3. System according to claim 1 or 2, wherein

in the first dilution stage (18), a first pressure measuring device is provided before, for measuring an actual value for the pressure at at least one point in the first dilution stage (18); and where

in the second dilution stage (21) a second pressure measuring device is provided for measuring an actual value for the pressure at at least one point in the second dilution stage (21).

4. System according to any one of the preceding claims, wherein

the control device is designed to set in each case the first and the second controlled proportional valve (26, 27) as a function of the pressure actual values measured by the respective pressure measuring devices and respective predetermined pressure setpoint values.

5. System according to any one of the preceding claims, wherein between the first dilution stage (18) and the second dilution stage (21) is a Klassifi ziereinrichtung (10) is arranged, for classifying the particles in the particle flow.

6. System according to any one of the preceding claims, wherein for generating the pressure gradient in the dilution system (8) between the dilution system (8) and the outlet (1 1) arranged pressure sink, in particular a pump (22) is arranged.

7. System according to any one of the preceding claims, wherein between the ers th dilution stage (18) and the second dilution stage (21) a pump, in particular a Venturi pump (20) is provided.

8. System according to any one of the preceding claims, wherein

a control device for regulating a gas flow serving as a setpoint between the first dilution stage (18) and the second dilution stage (21) is provided;

a gas flow measuring device is provided between the first dilution stage (18) and the second dilution stage (21), for measuring an actual value for the gas flow which can be supplied to the control device; and where

by the control device, the pump power of the Venturi pump (20) is adjustable to influence the actual value such that it approaches the target value.

9. System according to any one of the preceding claims, wherein an ambient air supply is provided, with a to the second dilution stage (21) leading ambient air supply line (34) for supplying ambient air to the second dilution stage (21).

10. System according to any one of the preceding claims, wherein a further ambient air supply line (37) is provided for supplying ambient air for operating the venturi pump (20).

1 1. A system according to any one of the preceding claims, wherein

in the leading to the second dilution stage (21) ambient air to line (34) a mass flow measuring device (35) is provided; and wherein - the ambient air supply line (37) leading to the venturi pump (20) branches off from the ambient air supply line (34) leading to the second dilution stage (21) at a location downstream of the mass flow meter (35).

12. System according to any one of the preceding claims, wherein between the Venturi pump (20) and the second dilution stage (21) and / or between the

Classifier (10) and the second dilution stage (21) a bypass (31) to the outlet (1 1) is provided.

13. The system according to any one of the preceding claims, wherein the downstream of the second dilution stage (21) provided Partikel- Bereitsein device comprises a particle supply line (24), for guiding the second dilution stage (21) leaving the aerosol stream to a stream with the aerosol device to be supplied.