WO2022262881A1

WO2022262881A1 - Combined microparticle impactor

Info

Publication number: WO2022262881A1
Application number: PCT/CZ2021/050065
Authority: WO
Inventors: Libor OBAL; Jakub KORPAS; Ladislav BLAHOUT
Original assignee: Technické Služby Ochrany Ovzduší Ostrava Spol. S R. O.; Vysoká Škola Báňská - Technická Univerzita Ostrava
Priority date: 2021-06-18
Filing date: 2021-06-18
Publication date: 2022-12-22

Abstract

The present invention relates to a combined microparticle impactor for the separation of microparticles from a fluid medium, comprising a first separation segment comprising an inlet head (1) with at least one inlet opening (2), a press-on segment (5a) of the first separation segment with a central opening (17a) and side openings (14.1), a filter holder (6a) of the first separation segment with a central surface (18a) for positioning a filter (19a) of the first separation segment and with side openings (14.2), an outlet member (3) with an outlet opening (4), and a fixing means (11) for mutual fixation of the inlet head (1) and the outlet member (3). After mounting the press-on segment (5a) and the filter holder (6a) to the inlet head (1), each inlet opening (2) is arranged above the central opening (17a) of the press-on segment (5a) and the central surface (18a) of the filter holder (6a) and off the side openings (14.1, 14.2) thereof. The impactor optionally further comprises additional separation segments (7, 8) for positioning filters (19b, 19c) of the additional separation segments (7, 8) and/or a support element (10) for positioning an outlet filter (20).

Description

Combined microparticle impactor

The present invention relates to a combined microparticle impactor. The present invention also relates to monitoring and measurement of emissions of solid pollutants at their source with separation of the fine grain fractions, including PM₁₀, PM_2,5 and PM₁.

A number of sampling apparatuses for the measurement of solid pollutants is currently commercially available, including the separation of fine grain fractions, including PM₁₀, PM_2,5 and PM₁. PM fraction separators work on different principles.

In the US, a cyclone separation system of these particles is commonly used by means of different separation speeds, the principle of which is set out in the document "Method 201A - Determination of PM₁₀ and PM_2.5 emissions from stationary sources (constant sampling rate procedure)" (https://www.epa.gov/sites/production/files/2019-08/documents/method_201a_0.pdf; available on 18 June 2021). This system is supplied, for example, by Apex Instruments (https://www.apexinst.com/product/method-201a-determination-pm10-pm2-5-emissions; available on 18 June 2021).

In Europe, sampling equipment with a system of separation using cascade impactors is mainly used. These can vary by placing the impactor on a probe as well as being on its own, whether sampling takes place behind a sampling probe or ahead of it directly in the pipe where the particles occur (e. g. in the flue).

DEKATI Ltd. supplies the Dekati PM10 Impactor system (https://www.dekati.com/products/dekati-pm10-impactor/; available on 18 June 2021). TECORA supplies the PM10, PM2.5 (https://www.tcr-tecora.com/wp-content/uploads/2019/05/EI.006.02.19.EN_MSSI.pdf; available on 18 June 2021).

Other similar impactors are also known from US patent applications US 2005081600 A1 and US 2004025567 A1. WO 0221104 A1 is also a well-known cascade impactor. A US patent US 4211116 A discloses a sampling assembly comprising an impactor. From the US patent US 4189937 A, an impactor with an annular impact surface and a screw tightening system is known.

The German patent DE 3545120 A1 discloses an impactor with three separation openings comprising annular gaps, wherein the capture surface (substrate) is also annular and the whole is compressed through the centre of the device.

The Chinese utility models CN 202420926 U, CN 207751751 U and CN 201622187 U disclose separation heads for the determination of atmospheric immisions.

Disadvantages of the above-mentioned impactors define the technical problem of prior art impactors, having a complex structure, being impossible to be placed both behind a sampling probe and directly into the flue without the need for surface heating, and having difficulties in handling in hot flue gas and during disassembling, which is associated with a high probability of losing a part of the sample.

The state of the art hence implies the need for a structurally simpler and variably positionable impactor, which is easily manipulated in hot flue gas as well as during sampling.

The aim of the present invention is to provide a microparticle impactor that solves the above-formulated technical problem. This aim is achieved by combined microparticle impactor for the separation of microparticles from a fluid medium according to claim 1.

The impactor comprises a first separation segment comprising an inlet head with at least one inlet opening for supplying fluid medium comprising microparticles, a ring-shaped press-on segment with a central opening and side openings, a ring-shaped filter holder with a central surface for positioning a filter of the first separation segment and with side openings, an outlet member with an outlet opening for discharging the fluid medium at least partially free of microparticles and a fixing means (e. g. a swivel nut, a tightening nut) for mutual fixation of the inlet head and the outlet member. The inlet head is dimensioned according to ČSN EN 23210 standard for the first separation segment in case of capturing solid particle fractions.

In an assembled state of the impactor, the press-on segment is mounted to the inlet head, the filter holder is mounted and fastened to the press-on segment, and the outlet member is mounted to the filter holder. When the press-on segment and the filter holder are mounted on the inlet head, each inlet opening is arranged above the central opening of the press-on segment and the central surface of the filter holder, and at the same time off the side openings thereof (i. e. not directly above them, off-set).

The impactor for microparticle separation is constructed such that the change in the direction of particle movement in the flowing gas occurs from the centre to the edges of the impactor. This solution allows the use of solid circular filters instead of filter rings in the case of an inverted direction of gas flow (from the edge to the centre). This will facilitate the preparation of filter matrices for fraction capturing. The basic version of the capturing element is constructed for circular filters having a diameter of 47 mm (a standard size) or 38 mm for separation operations. A filter cutter having a diameter of 38 mm is also commercially available, wherein the cutting can be made from a filter having a diameter of 47 mm. The side openings are used for the passage of the fluid medium and the central surface of the filter holder supporting the filter serves to remove microparticles based on aerodynamic properties.

The inlet head can preferably comprise multiple inlet openings, e. g. three, four or five openings. The inlet openings are arranged at a distance so that their central points align with a circumference of a circle. A lower number of inlet openings (e. g. one) is suitable for sampling with a higher particle concentration and a lower medium sampling rate, in other words with a lower medium volume flow (e. g. approx. 1 m³/hour), and therefore a low volume of an obtained sample is sufficient, while a higher number of inlet openings (e. g. three) is suitable for sampling with a lower particle concentration (e. g. sampling behind a filter) and a higher medium sampling rate, in other words with a higher medium volume flow (e. g. approx. 1 m³/hour), and therefore a higher volume of an obtained sample is needed. The particle velocity is determined by the mass flow of the medium (with particles) and the cross-section of the channel. Therefore, at a higher sampling rate, there are more inlet openings, and therefore a larger cross-section, which adjusts the particle velocity to the value needed for optimal separation.

In addition, the combined microparticle impactor may further comprise at least one additional separation segment with separation openings, and a press-on segment and a filter holder of the additional separation segment. The press-on segment is ring-shaped with a central opening and side openings, and the filter holder is ring-shaped with a central surface for positioning a filter of the additional separation segment and with side openings. The press-on segment and the filter holder of the additional separation segment are therefore essentially identical to the press-on segment and the filter holder of the first separation segment.

In an assembled state, the additional separation segment is mounted to the filter holder of the previous separation segment, the press-on segment is mounted to the respective additional separation segment, the filter holder is mounted and fixed to the respective press-on segment, and in this case, the outlet member is mounted to the filter holder of the last additional separation segment. This allows to create multiple separation segments for the separation of microparticles with different diameters, e. g. microparticles having a diameter greater than 10 μm and PM₁₀, PM_2,5 and PM₁ microparticles. Similarly to what has been mentioned above, after mounting the press-on segment and the filter holder to the additional separation segment, the separation openings are arranged above the central opening of the press-on segment and the central surface of the filter holder, and off the side openings thereof (i. e. not directly above them, off-set).

Preferably, the separation openings are arranged at a distance on each additional separation segment such that their central points align with a circumference of at least one circle, optionally with a circumference of one, two, three or four circles. In total, there can be e. g. 4 to 12 separation openings on the second additional separation segment and e. g. 10 to 30 separation openings on the third additional separation segment. Similarly to the inlet openings, a lower number of separation openings (e. g. four on the second additional separation segment and eight or ten on the third additional separation segment) is suitable for sampling with a higher particle concentration and a lower medium sampling rate, in other words with a lower medium volume flow (e. g. approx. 1 m³/hour), and therefore a low volume of an obtained sample is sufficient, while a higher number of separation openings (e. g. twelve on the second additional separation segment and thirty on the third additional separation segment) is suitable for sampling with a lower particle concentration (e. g. sampling after a filter) and a higher medium sampling rate, in other words with a higher medium volume flow (e. g. approx. 1 m³/hour), and therefore a higher volume of an obtained sample is needed. The particle velocity is determined by the mass flow of the medium (with particles) and the cross-section of the channel. Therefore, at a higher sampling rate, there are more separation openings, and therefore a larger cross-section, which adjusts the particle velocity to the value needed for optimal separation.

The diameter d ₁ of the inlet opening of the first separation segment is generally greater than the diameter d ₂ , d ₃ of the separation openings of the additional separation segment, and wherein if at least two additional separation segments are present, the diameter d ₂ of the separation openings of a previous additional separation segment is greater than the diameter d ₃ of the separation openings of a following additional separation segment in the flow direction of the fluid medium. Thus, the diameter of the openings in the separation segments is decreasing in the flow direction of the fluid medium through the impactor.

The ratio of the distance s ₁, s ₂, s ₃ from the inlet opening or the separation openings facing the outlet member (in the flow direction of the fluid medium) to the central surface of the filter holder directly below the inlet opening, and the diameter d ₁, d ₂, d ₃ of the inlet opening (2) or the separation openings (12, 13) is in the range of 0.5-5, e. g. 0.9-4.0, wherein the ratio s _n/d _n of the present separation segments increases in the flow direction of the fluid medium. These ratios are a condition of Reynolds' number.

The ratio of the length l ₁, l ₂, l ₃ of the inlet opening or the separation openings to the diameter d ₁, d ₂, d ₃ of the inlet opening or the separation openings is in the range of 0.25-2, e. g. 1.00-1.83, wherein the ratio l _n/d _n of the present separation segments decreases in the flow direction of the fluid medium. These ratios are a condition of Reynolds' number.

In addition, the combined microparticle impactor may further comprise a delimiting segment with a central opening, which is mounted to the filter holder of the last separation segment in an assembled state, and a support element with perforations for positioning an outlet filter. The support element is inserted in an assembled state between the filter holder of the last separation segment and the delimiting segment. In this case, the outlet member in an assembled state is mounted to the delimiting segment. The outlet filter allows to capture microparticles having a diameter smaller than or equal to 1 μm.

In all the above embodiments, the filter holder can be fastened to the press-on segment by means of at least one fixation element on the filter holder and at least one fixation opening on the press-on segment, thereby fixing the filter in an assembled state between the central opening of the press-on segment and the central surface of the filter holder, i. e. under the inlet opening(s) or under the separation openings, and at the same time off the side openings. The side openings of the press-on segment overlap with the side openings of the filter holder due to minimum number of obstacles for the flowing fluid medium.

Preferably, the inlet is of conical (tapered) shape narrowing in the flow direction of the fluid medium (i. e. having a wider base towards the outside from the impactor). Preferably, the outlet opening is of conical (tapered) shape narrowing in the flow direction of the fluid medium (i. e. having a wider base towards the inside of the impactor).

the inlet head may further comprise a circular recess above the side openings, wherein the circular recess is arranged above the level of the inlet opening facing the space above the central opening and the central surface. This inlet opening with the circular recess affects the flow characteristics above the first filter, owing to which the particles having a diameter larger than 10 μm are captured on it.

The impactor can be made of stainless steel or titanium for special sampling. It can be implemented on virtually any sampling apparatus for measuring solid pollutants according to EN 13284, since it is a so-called internal impactor which is placed directly in the flue during the sampling of microparticles, with no losses during sampling within the sampling probe.

This impactor allows the fractions of solid pollutants of required dimensions to be separated from the exhaust gas (flue gas) on the basis of aerodynamic properties of the particles, e. g. a total fraction of solid pollutants, i. e. a fraction of particles above PM₁₀ (i. e. having a diameter larger than 10 μm), PM₁₀ particles (i. e. having a diameter smaller than or equal to 10 μm), PM_2,5 particles (i. e. having a diameter smaller than or equal to 2,5 μm) and PM₁ particles (i. e. having a diameter smaller than or equal to 1 μm).

In general, however, any filter of the separation segment or the outlet filter is configured to capture microparticles having an aerodynamic diameter n, where preferably n > 10 μm and/or n = 10-1 μm and/or n < 1 μm. If at least two filters in the flow direction of the fluid medium are present, the filter of the previous separation segment is configured to capture microparticles having a diameter n₁ and the filter of the following separation segment is configured to capture microparticles having a diameter n₂, where n₁ > n₂. Therefore, in the flow direction of the fluid medium, the filters are in a certain order, such as a filter of total solid pollutant fraction (the filter of the first separation segment capturing microparticles having a diameter larger than 10 μm and allowing to pass PM₁₀ microparticles having a diameter smaller than or equal to 10 μm), a PM₁₀ filter (the filter of the additional second separation segment capturing microparticles having a diameter larger than 2.5 μm and allowing to pass PM_2,5 microparticles having a diameter smaller than or equal to 2,5 μm), a PM_2,5 filter (the filter of the additional third separation segment capturing microparticles having a diameter larger than 1 μm and allowing to pass PM₁ microparticles having a diameter smaller than or equal to 1 μm) and a PM₁ filter (the outlet filter capturing PM₁ microparticles having a diameter smaller than or equal to 1 μm).

This impactor therefore has a simpler structure and is easier to manipulate with the possibility of placing behind the sampling probe as well as directly into the flue without the need for surface heated. Owing to such simpler design, even if placed in hot flue gas, it is easier to manipulate when being disassembled and there is therefore less chance of losing a part of the sample. Another advantage is its lower financial cost.

The underlying idea of the invention is further clarified in the examples of the embodiment, which are described using the accompanying drawings, where:

Fig.1

shows a schematic side cross-sectional view of the combined microparticle impactor according to the invention;

Fig.2

shows a side cross-sectional view of the inlet head (the first separation segment) with one inlet opening;

Fig.3

shows a side cross-sectional view (A) and a top cross-sectional view (B) of the inlet head (the first separation segment) with three inlet openings;

Fig.4

shows a side cross-sectional view of the outlet member;

Fig.5

shows a side cross-sectional view and a top view of the press-on segment;

Fig.6

shows a side cross-sectional view and a top view of the filter holder;

Fig.7

shows a side cross-sectional view and a top view of the second separation segment with four separation openings;

Fig.8

shows a side cross-sectional view and a top view of the second separation segment with twelve separation openings;

Fig.9

shows a side cross-sectional view and a top view of the third separation segment with eight separation openings;

Fig.10

shows a side cross-sectional view and a top view of the third separation segment with thirty separation openings;

Fig.11

shows a side cross-sectional view and a top view of the delimiting segment;

Fig.12

shows a side cross-sectional view and a top view of the support element;

Fig.13

shows a side cross-sectional view of the fixing means;

Fig.14

shows a side cross-sectional view of the combined microparticle impactor according to one embodiment; and

Fig.15

shows a side cross-sectional view of the combined microparticle impactor according to another embodiment.

Examples

The invention will be further clarified on the examples of embodiments with reference to the corresponding drawings.

According to , the first exemplary embodiment is a combined microparticle impactor comprising only the first separation segment comprising an inlet head 1 with one to three inlet openings 2 ( , 3), a ring-shaped press-on segment 5a with a central opening 17a and side openings 14.1 ( ), a ring-shaped filter holder 6a with a central surface 18a for positioning a filter 19a of the first separation segment for capturing microparticles and with side openings 14.2 ( ), and an outlet member 3, the inner cavity of which conically narrows into an outlet opening 4 ( ). The inlet head 1 comprises a circular recess 21 above the level of the inlet opening 2 into the space above the central opening 17a and the central surface 18a ( ). The inlet opening 3 is mounted to the filter holder 6a, which is mounted to the press-on segment 5a, which is mounted to the inlet head 1. The filter holder 6a and the press-on segment 15 are further fastened by means of a pair of fixation elements 15 on the filter holder 6a and a pair of fixation openings 16 on the press-on segment 5a ( , 6). The mutual fixation of the inlet head 1 and the outlet member 3 is ensured by a fixing means 11, e. g. a swivel nut that compresses all components arranged between the inlet head 1 and the outlet member 3 ( ) by means of a threaded connection between the fixing means 11 and the outlet member 3. When the press-on segment 5a and the filter holder 6a is mounted to the inlet head 1, the inlet opening 2 is arranged above the central opening 17a of the press-on segment 5a and the central surface 18a of the filter holder 6a, and off the side openings thereof 14.1, 14.2, which serve for the passage of the fluid medium. The filter in the first separation segment is able to separate PM₁₀ microparticles, which are not captured on the filter 19a of the first separation segment, from microparticles having a diameter larger than 10 μm, which are captured on the filter 19a of the first separation segment.

The second exemplary embodiment according to is a combined microparticle impactor comprising two separation segments (first and additional second) comprising the impactor according to the first exemplary embodiment, with the difference that between the filter holder 6a and the outlet member 3, there is also a second separation segment 7 with circularly arranged separation openings 12 in the amount of 4-12 ( , 8), a ring-shaped press-on segment 5b with a central opening 17b and side openings 14.1 ( ), and ring-shaped a filter holder 6b with a central surface 18b for positioning a filter 19b of the second separation segment for capturing microparticles and with side openings 14.2 ( ). The outlet member 3 is mounted to the filter holder 6b, which is mounted to the press-on segment 5b, which is mounted to the separation segment 7, which is mounted to the filter holder 6a according to the first exemplary embodiment. The fixing device 11 and fixation of the filter holder 6b and the press-on segment 5b is according to the first exemplary embodiment. After mounting the press-on segment 5b and the filter holder 6b to the separation segment 7, the separation openings 12 are arranged above the central opening 17b of the press-on segment 5b and the central surface 18b of the filter holder 6b, and off the side openings 14.1, 14.2 thereof, which serve for the passage of the fluid medium. The filter in the first separation segment is able to separate PM₁₀ microparticles, which are not captured on the filter 19a of the first separation segment, from microparticles having a diameter larger than 10 μm, which are captured on the filter 19a of the first separation segment, and further to separate in the second separation segment the PM_2,5 microparticles, which are not captured on the filter 19b of the second separation segment, from microparticles having a diameter larger than 2,5 μm, which are captured on the filter 19 b of the second separation segment.

The third exemplary embodiment according to is a combined microparticle impactor comprising three separation segments (first, additional second and additional third) comprising the impactor according to the second exemplary embodiment, with the difference that between the filter holder 6b and the outlet member 3, there is also a third separation segment 8 with circularly arranged separation openings 13 in the amount of 8-30 ( -10), a ring-shaped press-on segment 5c with a central opening 17c and side openings 14.1 ( ), and a ring-shaped filter holder 6c with a central surface 18c for positioning a filter 19c of the third separation segment for capturing microparticles and with side openings 14.2 ( ). The outlet member 3 is mounted to the filter holder 6c, which is mounted to the press-on segment 5c, which is mounted to the separation segment 8, which is mounted to the filter holder 6b according to the second exemplary embodiment. The fixing device 11 and fixation of the filter holder 6c and the press-on segment 5c is according to the first exemplary embodiment. After mounting the press-on segment 5c and the filter holder 6c to the separation segment 8, the separation openings 13 are arranged above the central opening 17c of the press-on segment 5c and the central surface 18c of the filter holder 6c, and off the side openings thereof 14.1, 14.2, which serve for the passage of the fluid medium. The filter in the first separation segment is able to separate PM₁₀ microparticles, which are not captured on the filter 19a of the first separation segment, from microparticles having a diameter larger than 10 μm, which are captured on the filter 19a of the first separation segment, further to separate in the second separation segment the PM_2,5 microparticles, which are not captured on the filter 19b of the second separation segment, from microparticles having a diameter larger than 2,5 μm, which are captured on the filter 19 b of the second separation segment, and further to separate in the third separation segment the PM₁ microparticles, which are not captured on the filter 19 c of the second separation segment, from microparticles having a diameter larger than 1 μm, which are captured on the filter 19 c of the third separation segment.

The fourth exemplary embodiment according to Figs. 1, 14 and 15 is a combined microparticle impactor comprising one to three separation segments (first, additional second and additional third) comprising the impactor according to the first, second or third exemplary embodiment, with the difference that between the last filter holder 6a/6b/6c in the flow direction of the fluid medium and the outlet member 3 is a delimiting segment 9 with a central opening ( ) and a support element 10 with perforations for positioning an outlet filter 20 and which support element 10 is inserted between the last filter holder 6a/6b/6c and the delimiting segment 9 ( ). The outlet member 3 is mounted to the delimiting segment 9, which is mounted to the last filter holder 6a/6b/6c. The filter in the first separation segment is able to separate PM₁₀ microparticles, which are not captured on the filter 19a of the first separation segment, from microparticles having a diameter larger than 10 μm, which are captured on the filter 19a of the first separation segment, optionally further to separate in the second separation segment the PM_2,5 microparticles, which are not captured on the filter 19b of the second separation segment, from microparticles having a diameter larger than 2,5 μm, which are captured on the filter 19 b of the second separation segment, optionally further to separate in the third separation segment the PM₁ microparticles, which are not captured on the filter 19 c of the second separation segment, from microparticles having a diameter larger than 1 μm, which are captured on the filter 19 c of the third separation segment, and further on the outlet filter 20 to capture the PM₁ microparticles, i. e. microparticles having a diameter smaller than or equal to 1 μm.

In other examples, one can combine, remove or add these separation segments using a universal mounting system. For example, the press-on segment 5a and the filter holder 6a of the first separation segment, together with the second separation segment 7 can also be omitted by following the inlet element 1 directly with the press-on segment 5b of the second separation segment and/or the press-on segment 5c of the third separation segment. When viewed from above, the components have a circular shape, where each component comprises openings for the passage of the medium such that the

separation segments

1, 7, 8 have

openings

2, 12, 13 for the passage of the fluid medium arranged in the central portion, i. e. the inlet opening 2 for the inlet head 1, the separation openings 12 for the separation segment 7, and the separation openings 13 for the separation segment 8. For the press-on segments 5a/5b/5c and the filter holders 6a/6b/6c, the side openings are 14.1, 14.2 for the passage of the medium are identical and arranged above each other in the circumferential portion of components 5a/5b/5c and 6a/6b/6c.

Dimensional parameters of the inlet opening 2 and the

separation openings

12, 13 have been calculated for the third and fourth exemplary embodiments, see Table 1. Other diameters d with regard to Reynolds’ number cannot be used.

Table 1. Exemplary parameters of the inlet opening 2 (separation area 10 μm) and the separation openings 12, 13 (separation areas 2.5 and 1 μm, respectively).

				criterion s/d			criterion l/d
separation area μm	opening diameter d (mm)	opening length l (mm)	impact distance s (mm)	min	max	example	min	max	example
10	9.55	17.5	8.6	0.5	5	0.9	0.25	2	1.83
2.5	2.45	3	4			1.6			1.22
1	1.00	1	4			4.0			1.00

The principle of function of the impactor according to the fourth exemplary embodiment is as follows. The fluid medium comprising microparticles enters through the inlet opening 2 in the inlet head 1 of the impactor. The geometry of the opening of the inlet head 1 inwards of the impactor achieves such medium flow properties from the central to the circumferential portion above the surface of the filter 19a located on the filter holder 6a that the desired fraction of particles is captured based on their aerodynamic diameter on the filter 19a (substrate). The filter 19a is located on the central surface 18a of the filter holder 6a and fastened by the ring-shaped press-on segment 5a, the central opening 17a of which defines the area of the filter 19a. The medium stripped of the first fraction of particles passes through the side openings 14.1, 14.2 arranged around the circumference of the press-on segment 5a and the filter holder 6a. It also passes through the separation openings 12 in the separation segment 7, arranged in the central portion of the separation segment 7. The geometry of the separation openings 12 achieves such medium flow properties from the centre to the circumference above the following filter 19b positioned on the following filter holder 6b, thus separating the next required fraction of particles based on their aerodynamic diameter. The filter 19b is again fastened on the filter holder 6b by the press-on segment 5b. The medium stripped of the second fraction of particles passes through the lateral openings 14.1, 14.2 arranged around the circumference of the press-on segment 5b and the filter holder 6b and passes through the separation openings 13 in the separation segment 8, arranged in the central portion of the separation segment 8. The geometry of the separation openings 13 achieves such medium flow properties from the centre to the circumference above the following filter 19c positioned on the following filter holder 6c, thus separating the next required fraction of particles based on their aerodynamic diameter. The filter 19c is again fastened on the filter holder 6c by the press-on segment 5c. The medium stripped of the third fraction of particles, passes through the lateral openings 14.1, 14.2 arranged around the circumference of the press-on segment 5c and the filter holder 6c, and then passes through the outlet filter 20 positioned on the support element 10. Here, the residual amount of particles is separated from the medium and the medium then passes through the delimiting segment 9 through the conical tube of the outlet member 3 to the outlet opening 4.

The disclosed impactor can be used to determine relevant PM₁₀, PM_2,5 and PM₁ fractions in industrial plant emissions and in long-term sampling of ambient air (in immisions). Various other substances such as heavy metals, PCDD/F, benzo(a)pyrene, etc. can then be analysed as part of the obtained solid pollutant samples.

1 inlet head (first separation segment)
2 inlet opening
3 outlet member
4 outlet opening
5a, 5b, 5c press-on segment
6a, 6b, 6c filter holder
7 second separation segment
8 third separation segment
9 delimiting segment
10 support element
11 fixing means
12 separation opening of the second separation segment
13 separation opening of the third separation segment
14.1 side opening of the press-on

segment

5a, 5b, 5c
14.2 side opening of the

filter holder

6a, 6b, 6c
15 fixation element of the

filter holder

6a, 6b, 6c
16 fixation opening of the press-on

segment

5a, 5b, 5c
17a, 17b, 17c central opening of the press-on

segment

5a, 5b, 5c
18a, 18b, 18c central surface of the

filter holder

6a, 6b, 6c
19a, 19b, 19c filter
20 outlet filter
21 circular recess

Claims

A combined microparticle impactor for the separation of microparticles from a fluid medium, characterised in that it comprises:
a first separation segment comprising an inlet head (1) with at least one inlet opening (2) for supplying fluid medium comprising microparticles;

a press-on segment (5a) of the first separation segment, the press-on segment (5a) being ring-shaped with a central opening (17a) and side openings (14.1) for the passage of the fluid medium, wherein the press-on segment (5a) is mountable to the inlet head (1);

a filter holder (6a) of the first separation segment, the filter holder (6a) being ring-shaped with a central surface (18a) for positioning a filter (19a) of the first separation segment and with side openings (14.2) for the passage of the fluid medium, wherein the filter holder (6a) is mountable and fastenable to the press-on segment (5a);

an outlet member (3) with an outlet opening (4) for discharging the fluid medium at least partially free of microparticles, the outlet member (3) being mountable to the filter holder (6a); and

a fixing means (11) for mutual fixation of the inlet head (1) and the outlet member (3);
wherein, after mounting the press-on segment (5a) and the filter holder (6a) to the inlet head (1), each inlet opening (2) is arranged above the central opening (17a) of the press-on segment (5a) and the central surface (18a) of the filter holder (6a) and off the side openings (14.1, 14.2) thereof.
The combined microparticle impactor according to claim 1, wherein it comprises the first separation segment comprising the inlet head (1) with three inlet openings (2) for the inlet of fluid medium comprising microparticles, wherein the inlet openings (2) are arranged at a distance so that their central points align with a circumference of a circle.
The combined microparticle impactor according to claim 1 or 2, wherein it further comprises:
at least one additional separation segment (7, 8) with separation openings (12, 13) for the passage of fluid medium partially free of microparticles, wherein the additional separation segment (7, 8) is mountable on the filter holder (6a, 6b) of a previous separation segment;

a press-on segment (5b, 5c) of the additional separation segment, the press-on segment (5b, 5c) being ring-shaped with a central opening (17b, 17c) and side openings (14.1) for the passage of fluid medium, wherein the press-on segment (5b, 5c) is mountable to the additional separation segment (7, 8);

a filter holder (6b, 6c) of the additional separation segment, the filter holder (6b, 6c) being ring-shaped with a central surface (18b, 18c) for positioning a filter (19b, 19c) of the additional separation segment and with side openings (14.2) for the passage of fluid medium, wherein the filter holder (6b, 6c) is mountable and fastenable to the press-on segment (5b, 5c) of the additional separation segment;
wherein after mounting the press-on segment (5b, 5c) and the filter holder (6b, 6c) to the additional separation segment (7, 8), the separation openings (12, 13) are arranged above the central opening (17b, 17c) of the press-on segment (5b, 5c) and the central surface (18b, 18c) of the filter holder (6b, 6c), and off the side openings (14.1, 14.2) thereof,
wherein the outlet member (3) is mountable to the filter holder (6b, 6c) of the last additional separation segment.
The combined microparticle impactor according to claim 3, wherein the separation openings (12, 13) are arranged at a distance on each additional separation segment (7, 8) such that their central points align with a circumference of at least one circle, optionally with a circumference of one, two, three or four circles.
The combined microparticle impactor according to claim 3 or 4, wherein the diameter d ₁ of the inlet opening (2) of the first separation segment is greater than the diameter d ₂ , d ₃ of the separation openings (12, 13) of the additional separation segment, and wherein if at least two additional separation segments are present, the diameter d ₂ of the separation openings (12) of a previous additional separation segment is greater than the diameter d ₃ of the separation openings (13) of a following additional separation segment in the flow direction of the fluid medium.
The combined microparticle impactor according to any of claims 3 to 5, wherein the ratio of the distance s ₁, s ₂, s ₃ from the inlet opening (2) or the separation openings (12, 13) facing the outlet member (3) to the central surface (18a, 18b, 18c) and the diameter d ₁, d ₂, d ₃ of the inlet opening (2) or the separation openings (12, 13) is in the range of 0.5-5, wherein the ratio s _n/d _n of the present separation segments increases in the flow direction of the fluid medium.
The combined microparticle impactor according to any of claims 3 to 6, wherein the ratio of the length l ₁, l ₂, l ₃ of the inlet opening (2) or the separation openings (12, 13) to the diameter d ₁, d ₂, d ₃ of the inlet opening (2) or the separation openings (12, 13) is in the range of 0.25-2, wherein the ratio l _n/d _n of the present separation segments decreases in the flow direction of the fluid medium.
The combined microparticle impactor according to any of the previous claims, wherein it further comprises:
a delimiting segment (9) with a central opening, mountable to the filter holder (6a, 6b, 6c) of the last separation segment;

a support element (10) with perforations for positioning an outlet filter (20), wherein the support element (10) is insertable between the filter holder (6a, 6b, 6c) of the last separation segment and the delimiting segment (9);
wherein the outlet member (3) is mountable to the delimiting segment (9).
The combined microparticle impactor according to any of the previous claims, wherein the filter holder (6a, 6b, 6c) is fastened to the press-on segment (5a, 5b, 5c) by means of at least one fixation element (15) on the filter holder (6a, 6b, 6c) and at least one fixation opening (16) on the press-on segment (5a, 5b, 5c), thereby making the filter (19a, 19b, 19c) fixable between the central opening (17a, 17b, 17c) of the press-on segment (5a, 5b, 5c) and the central surface (18a, 18b, 18c) of the filter holder (6a, 6b, 6c) and off the side openings (14.1, 14.2) thereof.
The combined microparticle impactor according to any of the previous claims, wherein the side openings (14.1) of the press-on segment (5a, 5b, 5c) overlap with the side openings (14.2) of the filter holder (6a, 6b, 6c).
The combined microparticle impactor according to any of the previous claims, wherein the inlet opening (2) and/or the outlet opening (4) is of tapered shape narrowing in the flow direction of the fluid medium.
The combined microparticle impactor according to any of the previous claims, wherein the inlet head (1) comprises a circular recess (21) above the side openings (14.1, 14.2), wherein the circular recess (21) is arranged above the level of the inlet opening (2) facing the space above the central opening (17a) and the central surface (18a).
The combined microparticle impactor according to any of the previous claims, wherein any filter (19a, 19b, 19c) of the separation segment or the outlet filter (20) is configured to capture microparticles having an aerodynamic diameter n, wherein if at least two filters (19a, 19b, 19c, 20) in the flow direction of the fluid medium are present, the filter (19a, 19b, 19c) of the previous separation segment is configured to capture microparticles having a diameter n₁ and the filter (19b, 19c, 20) of the following separation segment is configured to capture microparticles having a diameter n₂, where n₁ > n₂.
The combined microparticle impactor according to any of the previous claims, wherein the filter (19a) of the first separation segment is configured to capture microparticles having a diameter larger than 10 μm, the filter (19b) of the additional second separation segment is configured to capture PM₁₀ microparticles having a diameter smaller than or equal to 10 μm, the filter (19c) of the additional third separation segment is configured to capture PM_2,5 microparticles having a diameter smaller than or equal to 2,5 μm, and the outlet filter (20) is configured to capture PM₁ microparticles having a diameter smaller than or equal to 1 μm.
The combined microparticle impactor according to any of the previous claims, wherein the filter (19a) of the first separation segment is configured to capture microparticles having a diameter larger than 10 μm, the filter (19b) of the additional second separation segment is configured to capture microparticles having a diameter larger than 2,5 μm, the filter (19c) of the additional third separation segment is configured to capture microparticles having a diameter larger than 1 μm, and the outlet filter (20) is configured to capture microparticles having a diameter smaller than or equal to 1 μm.