Handheld sampling-removal head, analysis arrangement and method for characterizing an aerosol

Abstract

In a sampling head (1) of an analysis arrangement (31), provision is made that a sample stream delivered via a sampling line (2) and a dilution air stream delivered through a dilution air inlet (4) are mixed together in a dilution unit (3) in such a way that a volumetric quantity entrained in at least one receiving space moved along by a movable element (8) between the sampling stream and the dilution air stream are exchanged with each other, wherein the analysis arrangement (31) has a gas analyzer (35) for the analysis of the slightly diluted sample stream and a particle determination unit (32) for the analysis of the enriched dilution air stream.

Claims

1. A hand-held sampling head (1) for collecting a sample of an aerosol containing suspended particles, comprising a sampling line (2) and an integrated dilution unit (3) which is connected to the sampling line (2) and which has a dilution air inlet (4), the dilution unit (3) has a first element (6) with a first contact face (7) and a second element (8) with a second contact face (9), which are arranged to be movable relative to each other and which are in flat contact with each other via the respective contact faces (7, 9), a sample channel (10) open toward the second element (8) is formed in the first element (6) in the first contact face (7) and is connected to the sampling line (2), a dilution air channel (11) open toward the second element (8) is formed in the first element (6) in the first contact face (7) and is connected to the dilution air inlet (4) and to a tube for a particle determination unit, and at least one receiving space (14) open toward the first element (6) is formed in the second element (8) in the second contact face (9) in such a way that the receiving space (14), during a relative movement (28) of the first element (6) with respect to the second element (8), is brought into connection successively with the sample channel (10) and with the dilution air channel (11), and the first element (6) and the second element (8) are made from ceramic, and the dilution air inlet (4) is connected to the first element (6) at one end of the dilution air channel (11) on a side of the first element (6) which faces away from the second element (8) and the tube for the particle determination unit is also connected to the dilution air channel (11) on the side of the first element (6) which faces away from the second element (8).

2. The sampling head (1) as claimed in claim 1, wherein at least one of the first element (6) or the second element (8) are disk-shaped.

3. The sampling head (1) as claimed in claim 1, wherein the first element (6) is stationary, and the second element (8) is mounted rotatably.

4. The sampling head (1) as claimed in claim 1, wherein the second element (8) is arranged in a rotationally fixed manner on a driven shaft (15), or a shaft (15) passes through the first element (6), or the shaft (15) is driven at that side of the first element (6) directed away from the second element (8).

5. The sampling head (1) as claimed in claim 1, wherein the dilution unit (3) is arranged under a cover cap (22), the cover cap (22) is connected detachably to a housing (23) of the sampling head (1), or a resilient element acts axially on the second element (8), with the resilient element (24) being supported on a cover cap (22).

6. The sampling head (1) as claimed in claim 1, wherein the first element (6) and the second element (8) are made from identical material.

7. The sampling head (1) as claimed in claim 1, wherein a heating device (25) is integrated for heating the dilution unit (3), or a heating device has a heating foil (25) which lies flat on the first element (6) or on the second element (8), or a heating foil (25) is arranged on a side of the first element (6) directed away from the second element (8).

8. The sampling head (1) as claimed in claim 1, wherein at least one of the first element (6) or the second element (8) is enclosed by a heat-insulating capsule (26).

9. The sampling head (1) as claimed in claim 1, wherein the tube is connected to the dilution air channel (11) downstream of the dilution unit (3) in a flow direction (30), and the tube (34) is made of electrically conductive material.

10. The sampling head (1) as claimed in claim 1, wherein a plurality of receiving spaces are provided, and a counting device is configured for the receiving spaces (14) that are guided to and fro per unit of time between the sample channel (10) and the dilution air channel (11).

11. An analysis arrangement (31) for characterizing an aerosol, comprising a sampling head (1) as claimed in claim 1, connected to a portable analysis appliance.

12. The analysis arrangement (31) as claimed in claim 11, wherein a dilution air filter (49) is integrated in the analysis appliance and is connected to the dilution air inlet (4) of the sampling head (1), or the analysis appliance has an impactor (33) which is connected to the dilution air channel (11) of the dilution unit (3), or the analysis appliance has at least one sensor (36) which is used to determine at least one gaseous constituent in a carrier gas of the aerosol and which is connected to the sample channel (10) of the dilution unit (3).

13. The analysis arrangement (31) as claimed in claim 12, wherein the analysis appliance has a pump (42) which is arranged downstream of an impactor (33) in the suction direction, or the analysis appliance has a pump which is arranged upstream of the at least one sensor (36) in the suction direction.

14. The sampling head (1) as claimed in claim 1, wherein the first element (6) and the second element (8) are arranged to be rotatable relative to each other about a rotation axis.

15. The sampling head (1) as claimed in claim 1, wherein the first contact face (7) bears in a gas-tight manner on the second contact face (9).

16. The sampling head (1) as claimed in claim 1, wherein at least one of the sample channel (10) or the dilution channel (11) is kidney-shaped along an arc of a circle.

17. A method for characterizing an aerosol, said aerosol having a carrier gas and suspended particles received therein, the method comprising delivering a sample stream, containing the aerosol, and a dilution air stream to a dilution unit (3), exchanging a predefined volumetric quantity of the sample stream and a predefined volumetric quantity of the dilution air stream with each other in the dilution unit, delivering the dilution air stream to a particle determination unit (32) downstream of the dilution unit (3) in flow direction (30), using said particle determination unit (32) to determine at least one of a number or mass fractions of the suspended particles, and, downstream of the dilution unit (3) in flow direction (29), delivering the sample stream to at least one sensor (36) for determining at least one gaseous constituent in the carrier gas of the aerosol, and exchanging a volumetric quantity in the dilution unit (3) per unit of time, by which a predefined dilution ratio in the dilution air stream is set, and measuring the volumetric quantity exchanged per unit of time by counting how often per unit of time at least one receiving space (14) between the sample stream and the dilution air stream is moved to and fro.

18. The method as claimed in claim 17, wherein a volumetric quantity in the dilution unit (3) is exchanged per unit of time, by which a predefined dilution ratio in the dilution air stream is set, or the dilution air stream is generated with constant volume.

19. The method as claimed in claim 17, wherein at least one of the sample stream is heated upstream of the dilution unit (3), the dilution unit (3) is heated, the dilution air stream downstream of the particle determination unit (32) is delivered through a buffer volume (43), followed by a capillary (44), to a pump (42), or a pressure drop in the dilution air stream across the particle determination unit (32) or at least one of the volumetric flow of the dilution air stream is measured.

20. The method as claimed in claim 17, wherein at least one of the volumetric quantity is exchanged by at least one of the receiving spaces (14) being brought into connection alternately with the sample stream and the dilution air stream, or the volumetric quantity exchanged per unit of time is measured, by counting how often per unit of time the at least one receiving space (14) between the sample stream and the dilution air stream was moved to and fro.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is now described on the basis of an illustrative embodiment, but it is not limited to this illustrative embodiment. Further illustrative embodiments result from combining individual features or several features of the claims with each other and/or with individual or several features of the illustrative embodiment.

(2) FIG. 1 shows a three-dimensional sectional view of a sampling head according to the invention;

(3) FIG. 2 shows the dilution unit of the sampling head from FIG. 1 in a partially exploded view;

(4) FIG. 3 shows the sampling head according to the invention from FIG. 1, in a three-dimensional sectional view seen from another angle;

(5) FIG. 4 shows the dilution unit of the sampling head from FIG. 1 in a three-dimensional sectional view seen from another angle;

(6) FIG. 5 shows a first element, according to the invention, of the dilution unit from FIG. 2, looking toward the contact face;

(7) FIG. 6 shows the first element from FIG. 5 in a view from the opposite side;

(8) FIG. 7 shows the second element, according to the invention, of the dilution unit from FIG. 2, looking toward the contact face;

(9) FIG. 8 shows the second element from FIG. 7 in a view toward the opposite side;

(10) FIG. 9 shows a further three-dimensional sectional view of the sampling head from FIG. 1; and

(11) FIG. 10 shows the gas route plan of an analysis arrangement according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(12) FIGS. 1 to 9 show different views or component parts of a sampling head, designated overall by 1, and are therefore described jointly hereinbelow.

(13) The sampling head 1 has a sampling line 2 via which an aerosol containing suspended particles is delivered to a dilution unit 3.

(14) The dilution unit 3 also has a dilution air inlet 4, via which dilution air is delivered to the dilution unit 3 from a dilution air hose 5.

(15) The dilution unit 3 has a first element 6, which is disk-shaped and provides a first contact face 7.

(16) The dilution unit 3 also has a second element 8, which is likewise disk-shaped and of which the basic form corresponds to that of the first element 6.

(17) The second element 8 provides a second contact face 9 which, in the position of use, lies flat and gas-tight on the first contact face 7.

(18) As can be seen in particular from the detailed views in FIG. 5 and FIG. 6, a sample channel 10 is formed in the first contact face 7 of the first element 6 and is open toward the second element 8 in the position of use.

(19) In the first contact face 7, a dilution air channel 11 is also formed which is likewise open toward the second element 8 in the position of use.

(20) The sample channel 10 and the dilution air channel 11 each extend in a kidney shape along an arc of a circle.

(21) These arcs of a circle have a corresponding radius and a corresponding center, which coincides with the center of rotation of the second element 8.

(22) The sample channel 10 is connected at one end 12 to the sampling line 2, while the dilution air channel 11 is connected at one end 13 to the dilution air inlet 4.

(23) Ten receiving spaces 14 are formed as cavities in the second contact face 9 of the second element 8.

(24) The receiving spaces 14 are arranged in a circle about the center point of the second element 8, which is at the same time the rotation point of the second element 8.

(25) In further illustrative embodiments, other numbers of receiving spaces 14 are formed, for example a single receiving space, two or three receiving spaces 14, or more than three receiving spaces 14.

(26) In the illustrative embodiment according to FIGS. 1 to 9, the receiving spaces 14 are arranged with respect to the center of rotation of the second element 8 in such a way that, upon rotation of the second element 8 with respect to the first element 6 in the position of use, the receiving spaces 14 are brought alternately into contact with the sample channel 10 and the dilution air channel 11 in succession.

(27) A gas exchange or aerosol exchange is thus possible between the content of the receiving space 14 on the one hand and the sample channel 10 or dilution air channel 11 on the other hand, resulting in an exchange of a volumetric quantity, predefined by the size of the receiving spaces 14, between a sample stream flowing in the sample channel 10 and a dilution air stream flowing in the dilution air channel 11.

(28) This has the effect that the dilution can be performed without a pressure increase on one side.

(29) In the relative movement of the second element 8 with respect to the first element 6, which in the illustrative embodiment shown is a rotational movement or similar circular movement, the first element 6 remains stationary, while the second element 8 is connected to a shaft 15 for rotation therewith, which shaft 15 is driven by a motor 16.

(30) For this purpose, the shaft 15 is guided through a central opening 17 of the first element 6 and engages right through this.

(31) Drivers 18 extending in the radial direction are formed on the shaft 15 and engage in matching recesses 19 on the second element 8 for rotationally fixed connection of the second element 8 plugged onto the shaft 15.

(32) The first element 6 is secured on the sampling head by securing means, which are inserted into four securing holes 50.

(33) An operative connection between the driven shaft 15 and the electric motor 16 is produced via a conical stage 20, wherein the electric motor 16 can be arranged with its longitudinal axis in the direction of extent of the handle 21.

(34) The dilution unit 3 is arranged under a detachable cover cap 22.

(35) The cover cap 22 is hood-shaped and connected to the rest of the housing 23.

(36) Between the second element 8 and the cover cap 22, a spring 24 (or another resilient element) is inserted which acts axially on the second element 8 and thus presses the first contact face 7 and the second contact face 9 onto each other for gas-tight closure.

(37) The first element 6 and the second element 8 are made from ceramic material, for example by being cast, pressed, sintered and/or milled.

(38) A heating foil 25 is placed flat on the rear face 51 of the first element 6 lying opposite the first contact face 7 and thus directed away from the second element 8, which heating foil 25, together with the associated electrical wiring (not shown), forms a heating device for heating the dilution unit 3.

(39) The thereby heated first element 6 is enclosed in a shell-shaped capsule 26 which insulates the handle 21 and the housing 23 from the heat generated by the heating foil 25.

(40) Along the sampling line 2, a heater 27 is formed with which the sampling line 2 can be kept above the condensation temperature of the aerosol.

(41) The heating foil 25 is likewise operated at a temperature that prevents condensation in the dilution unit 3.

(42) As can be seen more clearly from FIG. 5, the mouths of the sampling line 2 and of the dilution air inlet 4 are arranged at the ends 12, 13 of the sample channel 10 and of the air dilution channel 11 in such a way that, with respect to the relative movement 28, i.e. the rotation, of the second element 8 and the first element 6, mutually opposite flow directions 29, 30 are defined.

(43) In the illustrative embodiment, the flow directions 29, 30 thus both have the opposite sense of rotation to the relative movement 28.

(44) The indicated relative movement 28 designates the movement of the second element 8 in relation to the stationary first element 6.

(45) Thus, the receiving spaces 14 are guided along the dilution air channel 11 in the flow direction 30 thereof.

(46) The sampling head 1 shown in FIGS. 1 to 9 is used in an analysis arrangement 31, of which the gas route plan is shown in FIG. 10.

(47) It will be seen that the sampling head 1 is connected to an analysis appliance, which is formed by the details shown in FIG. 10 in addition to the dilution unit 3 and the sampling line 2.

(48) The analysis appliance of the analysis arrangement 31 accordingly has a particle determination unit 32 with an impactor 33, which is connected to the dilution air channel 11 via a measuring tube 34 (cf. FIGS. 1 to 5).

(49) The measuring tube 34 is made from silicone enriched with carbon, which forms an electrically conductive material.

(50) Mass fractions of the suspended particles in the aerosol can be determined with the particle determination unit 32.

(51) The analysis appliance of the analysis arrangement 31 also has an integrated gas analyzer, which has one or more sensors for determining at least one gaseous constituent in the carrier gas of the aerosol.

(52) Upstream of the gas analyzer 35 there are a combination appliance 37 (comprising a condensate trap and a fine filter) and a particle filter 39, which are connected to the outlet of the sample channel 10 by a sample line 40.

(53) Dilution air hose 5, measuring tube 34 and sampling line 40, and also electrical leads 41, are routed to the analysis appliance inside a sheath (not shown).

(54) The gas analyzer 35 is equipped with a pump (not shown) which generates a sample stream in the sample channel 10.

(55) Downstream of the impactor 33, there is a further pump 42 with which a dilution air stream in the dilution air channel 11 can be generated.

(56) To generate a uniform dilution air stream, a combination of a buffer volume 43 and of a capillary 44 downstream of the latter is provided for the pump 42. The capillary 44 is operated supercritically, such that an increase in the pump pressure does not cause any significant change of the delivery volume.

(57) For protection of the capillary 44, a filter 45 is arranged between buffer volume 43 and capillary 44.

(58) In a further illustrative embodiment, the capillary 44 and the filter 45 are not present.

(59) In the sampling head 1, the speed of the motor 16 (cf. FIG. 1) is regulated. In the sampling head 1 or the analysis appliance (in particular the particle determination unit 32) of the analysis arrangement 31, a counting unit (not shown) is formed which, from the actual speed, derives the number of the receiving spaces 14 moved to and fro by the rotation between the sample channel 10 and the dilution air channel 11, wherein each receiving space 14 moved to and fro several times is counted several times. In this way, knowing the volume of a receiving space 14, it is possible to calculate the amount of the sample added to the dilution air. Thus, the measurement result on the particle determination unit can be normalized to this volumetric quantity and/or to a normal volume.

(60) The impactor 33 of the illustrative embodiment according to FIG. 10 can be monitored by pressure sensors 46, 47, with which the pressure difference or pressure drop across the impactor 33 can be measured. The pumping power of the pump 42 is regulated on the basis of the measured pressure difference across the impactor 33.

(61) The dilution air stream can be monitored by a dV/dT sensor 48, with which a volumetric flow of the dilution air stream can be measured.

(62) With the buffer volume 43 and the capillary 44, a constant volumetric flow can be set for the dilution air stream, which is monitored by the pressure sensors 46, 47 and/or by the dV/dT sensor 48.

(63) In the analysis appliance of the analysis arrangement 31, a filter 49 is also arranged for cleaning the dilution air sucked through the dilution air hose 5.

(64) In the sampling head 1 of an analysis arrangement 31, provision is made that a sample stream delivered via a sampling line 2 and a dilution air stream delivered through a dilution air inlet 4 are mixed together in a dilution unit 3 in such a way that a volume quantity, entrained in at least one receiving space moved by a movable element 8, between the sampling stream and the dilution air stream is exchanged, wherein the analysis arrangement 31 has a gas analyzer 35 for the analysis of the slightly diluted sample stream and a particle determination unit 32 for the analysis of the enriched dilution air stream.