DE102020115540B4 - Device for diluting aerosols - Google Patents

Abstract

Device for diluting aerosols with a variable dilution factor for testing the degree of permeability of different filter devices with several dilution devices (1), each with an inlet (2) and an outlet (3) for the aerosol, with between the inlet (2) and the outlet ( 3) for dividing and mixing the volume flow, a hollow body (4) and a series connection of a filter (5) and a first valve (6) and for measuring the pressure of the partial flows of the aerosol a pressure measuring device (7) are arranged parallel to one another and the actuating device of the first valve (6) and the pressure measuring device (7) are connected to a control device, characterized in that the dilution devices (1) are connected in series, that in each of the dilution devices (1) one has at least one second valve (8). the inlet (2) and bypass line (10) connected to the outlet (3) via at least one third valve, that the second valve (8) and the third valve (9) are each a three-way valve or two two-way valves, and that the Actuating devices of the second valves (8) and the third valves (9) are connected to the control device in such a way that the inlet (2) and the outlet (3) of individual dilution devices (1) either via the hollow body (4) as a capillary and the series connection with the filter (5) and the first valve (6) or via the hollow body (4) as a capillary and the bypass line (10) are connected to one another, so that temporarily unnecessary individual dilution devices (1) can be passed through the bypass line contained therein ( 10) are ineffective.

Description

The invention relates to devices for diluting aerosols with a variable dilution factor for testing the degree of permeability of different filter devices with several dilution devices, each with an inlet and an outlet for the aerosol, with a hollow body (between the inlet and the outlet for dividing and mixing the volume flow ( Capillary) and a series connection of a filter and a first valve and for measuring the pressure of the partial flows of the aerosol a pressure measuring device are arranged parallel to one another and the actuating device of the first valve and the pressure measuring device are connected to a control device.

When using particle measurement technology for aerosols, a limited measuring range must be taken into account with regard to the particle number concentration (particles per unit volume of carrier gas). This is orders of magnitude below the concentrations found in many industrial and natural processes. Furthermore, the use of dilution systems to adjust the concentration of the aerosol from sampling for particle measurement is common. This technical device reduces the high concentration of the measuring location to a concentration that can be processed by particle measurement technology. In order to recalculate the measurement result to the original concentration at the measurement location, a reproducible and known dilution is required.

Dilution systems are known, for example, which divide the flow of the aerosol and completely remove the particles from a partial flow and, after subsequent mixing, cause a dilution corresponding to the partial flows. Through the publication DE 10 2014 200 823 A1 Device for generating an adjustable differential pressure of a compressible medium as it flows through a fluid guide, the publication DE 296 10 043 U 1 dilution device for sampling in highly concentrated aerosols and the publication DE 10 2008 047 404 A1 Such solutions are known, a device to be connected upstream of a particle counter for the self-contained dilution of aerosols.

These devices have a fixed dilution factor as the ratio of the concentrations of the undiluted to the diluted aerosol or can vary this η within a certain range. Due to the limited dilution range, these are not suitable for filter devices that vary greatly in their degree of permeability.

DE 10 2019 101 993 A1 relates to devices for checking filter test systems to determine the separation behavior of a filter device for gaseous fluid. The device has a first device for setting a certain differential pressure, a second device with a certain degree of separation of the gaseous fluid of the filter testing system flowing through the devices and two adapters for coupling on the inflow and outflow sides.

This means that a differential pressure and/or a degree of separation can be set variably and independently of one another and the first device and the second device are a filtration standard with permanently constant properties with regard to the set differential pressure and the set degree of separation as a reference device for simulating a filtering separator.

DE 10 2018 120 362 A1 describes a particle measurement system with a dilution device and a method for particle measurement, wherein a particle number is measured in an aerosol stream, for example in the exhaust gas stream from an internal combustion engine. The particle measuring system can have several dilution stages connected in series. This also includes a bypass, which has its own flow control or flow setting.

DE 10 2014 213 232 A1 discloses a device for in-situ adjustment of measuring systems for measuring the degree of separation on separators of impurities of a flowing fluid in a flow channel, which has several valve assemblies. The control device is a control device that can switch the flow paths between the measuring points of the test substance concentration and the measuring devices for the test substance concentrations in such a way that the measuring devices are connected either directly or via a dilution system either to the measuring points or together with only one of the measuring points for the test substance concentration.

The invention specified in claim 1 is based on the object of providing a dilution device for aerosols in such a way that filter devices that differ greatly in their degree of permeability can be easily tested.

This task is solved with the features listed in claim 1.

The devices for diluting aerosols with a variable dilution factor for testing different filter devices with multiple dilution devices, each with an inlet and an outlet for the aerosol, with between the in let and the outlet for dividing and mixing the volume flow, a hollow body (capillary) and a series connection/series arrangement with a filter and a first valve and for measuring the pressure of the partial flows of the aerosol a pressure measuring device are arranged parallel to one another and the actuating device of the first valve and the pressure measuring device are connected to a control device, are characterized in particular by the fact that filter devices with very different degrees of passage can be easily tested.

For this purpose, a bypass line is arranged in each of the dilution devices, connected to the inlet via at least a second valve and to the outlet via at least a third valve. The dilution devices of the device for diluting aerosols are connected in series. According to the invention, the second valve and the third valve are each a three-way valve or are each two two-way valves. Furthermore, the actuating devices of the second valves and the third valves are connected to the control device so that the inlet and the outlet of individual dilution devices either via the hollow body as a capillary and the series connection with the filter and the first three-way valve or the two first two-way valves or via the hollow body as Capillary and the bypass line are connected to each other, so that individual dilution devices that are not temporarily required are ineffective due to the bypass line contained in it.

The device is therefore particularly advantageous for applications in which very different aerosol concentrations are to be measured regularly. This can be a system for determining the separation efficiency of filter devices. If filter devices that are very different in terms of their degree of separation are tested with a constant inflowing aerosol, the outflowing aerosol passing through the filter devices has very different concentrations. Since the transmittance of a filter device, which is considered a quality parameter, results from the ratio of the concentrations of the outflowing to the inflowing aerosol, very different aerosol concentrations have to be measured here. The device can advantageously be used to test filter devices with very different transmittances, since the dilution factor of the device with the dilution devices can also be changed greatly.

With the design of the dilution devices with the bypass lines, an uninterrupted flow through the device with either one or no dilution is ensured while the connections between the dilution devices remain intact. In practice, the individual dilution devices can therefore be permanently cascaded for the maximum dilution factor. Individual dilution devices that are not required temporarily can be rendered ineffective by the bypass line they contain. All connections to the facility's dilution devices remain permanently in place. A manual setup process when changing the overall dilution ratio or switching using external devices is not necessary. Dilutions or bridging occur with the second valves and the third valves, whose actuating devices are connected to the control device. For this purpose, the inlet and the outlet of the dilution device are connected to one another either via the hollow body as a capillary and the series connection/series arrangement with the filter and the first valve or via the hollow body as a capillary and the bypass line.

This means that the device can be operated automatically without the need to convert dilution devices. No external devices are necessary for this.

Advantageous embodiments of the invention are specified in claim 2.

The control device can in particular be a data processing system that can be connected or is connected to a data network. This means that the device can advantageously also be controlled remotely. The advantage of equipping the dilution devices with a device for bridging the dilution is that the total dilution of the cascade from several dilution devices can be adjusted remotely and automatically without manual or other set-up processes.

An exemplary embodiment of the invention is shown in principle in the drawings and is described in more detail below.

• 1 eine Verdünnungseinrichtung mit einer Bypassleitung und
• 2 eine Einrichtung zum Verdünnen von Aerosolen mit mehreren Verdünnungseinrichtungen.

Show it:

• 1 a dilution device with a bypass line and
• 2 a device for diluting aerosols with several dilution devices.

A device for diluting aerosols with a variable dilution factor for testing the degree of permeability of different filter devices essentially consists of several dilution devices 1.

The 1 shows a dilution device 1 with a bypass line 10 in a basic representation.

The dilution device 1 each has an inlet 2 and an outlet 3 for the aerosol. Between the inlet 2 and the outlet 3 there is a hollow body 4 as a capillary and a series connection/series arrangement with a filter 5 and a first valve 6 for dividing and mixing the volume flow and for measuring the pressure of the partial flows of the aerosol a pressure measuring device 7 parallel to one another arranged. Furthermore, a bypass line 10 is arranged in the dilution device 1 and is connected to the inlet 2 via at least a second valve 8 and to the outlet 3 via at least a third valve 9. The pressure measuring device 7 and the actuating devices of the first valve 6, the second valve 8 and the third valve 9 are connected to a control device. The second valve 8 and the third valve 9 are in particular three-way valves, so that the dilution device 1 dilutes or does not dilute the aerosol.

The function is based on dividing the aerosol stream and then mixing the partial streams, with the particles being completely removed from one partial stream. This is done by the filter 5. If this is loaded with particles, the division ratio of the volume flows can be maintained by opening the first valve 6 accordingly. The adjustment is made using the pressure measuring device 7. The pressure should be constant. This division ratio determines the dilution factor of the dilution device 1. This dilution device 1 is expanded to include the bypass line 10. The dilution is thereby bridged, which means that the dilution factor takes on the value of one or the aerosol is passed through undiluted. By switching this internal bypass line 10 using the second valve 8 and the third valve 9, the partial flow that would otherwise be passed through the filter 5 can now be directed to the outlet 3 without being influenced. This means that no dilution takes place.

The 2 shows a device for diluting aerosols with several dilution devices 1 in a basic representation.

The device is a cascade of dilution devices 1, each of which is equipped with the bypass line 10. For example, the dilution devices 1a and 1c are active, their dilution factor is effective. The dilution device 1b is ineffective, the dilution factor has the value one. This is done by switching the internal bypass line 10 of the dilution device 1b.

Reference symbol list

1

Dilution device

2

inlet

3

outlet

4

Hollow body

5

filter

6

first valve

7

Pressure measuring device

8th

second valve

9

third valve

10

Bypass line

Claims (2)

Device for diluting aerosols with a variable dilution factor for testing the degree of permeability of different filter devices with several dilution devices (1), each with an inlet (2) and an outlet (3) for the aerosol, with between the inlet (2) and the outlet ( 3) for dividing and mixing the volume flow, a hollow body (4) and a series connection of a filter (5) and a first valve (6) and for measuring the pressure of the partial flows of the aerosol a pressure measuring device (7) are arranged parallel to one another and whereby the Actuating device of the first valve (6) and the pressure measuring device (7) are connected to a control device, characterized in that the dilution devices (1) are connected in series, that in each of the dilution devices (1) one has at least one second valve (8) with the inlet (2) and via at least one third valve connected to the outlet (3) bypass line (10) is arranged, that the second valve (8) and the third valve (9) are each a three-way valve or two two-way valves, and that the actuating devices of the second valves (8) and the third valves (9) are connected to the control device in such a way that the inlet (2) and the outlet (3) of individual dilution devices (1) either via the hollow body (4) as a capillary and the series connection with the filter (5) and the first valve (6) or via the hollow body (4) as a capillary and the bypass line (10) are connected to each other, so that temporarily unnecessary individual dilution devices (1) are contained in it Bypass line (10) is ineffective. Setup after Patent claim 1 , characterized in that the control device is a data processing system which can be connected or is connected to a data network.

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