FR2870938A1 - Aerosol collector, e.g. for analyzing aerosols created in industrial zones, has base of receptacle surrounded by chamber with heater - Google Patents

Abstract

An aerosol collector comprises a receptacle (2) with a vertical axis and an open top, having a conical base that is open at the bottom, and a surface (3A) on which the aerosols can be collected. The base of the receptacle is surrounded by a chamber (12) which has its lower edge (12A) situated at a distance from the open end of the cone, and against which a support (3) with the collecting surface is pressed. The chamber is surrounded by a heater (10), and the collector is fitted with a rain detector (9), preferably situated adjacent to the open end of the cone, while a vibrator (8) on the outside of the cone agitates the receptacle so that the aerosols drop down into the chamber. The collector and chamber rest on a vertically movable table (21) with a concave surface (21A) and a central hole (11).

Description

2870938 1

  The invention relates to a device for collecting aerosols.

  The aerosols that are generated especially in industrial areas can be analyzed to determine their composition and quantity.

  If it is interesting to know the quantity of aerosol per cubic meter at a given moment, it is also interesting to know the quantity that is deposited in a period of time at a given place and / or the periods of fallout of these aerosols. .

  Indeed, even if the aerosols can move over long distances, most of the aerosol deposits remain, however, located in the areas close to where these aerosols are generated, such as the powder storage areas, etc. For the collection of these aerosols the known devices conventionally comprise an open receptacle on the top, the conical lower part of which has an evacuation orifice.

  A manoeuverable shutter closing this orifice makes it possible to drop the aerosols into a container for periodic analysis, for example by weighing.

  These devices require the intervention of an attendant to collect the samples and, therefore, the difference between two measurements can be of the order of a week or more.

  Between two surveys, the rain can then disturb the measurement.

  Indeed, the rain modifies the behavior of aerosols and samples.

  In fact, the rain, having collected aerosols in its path, mixes with the aerosols already collected.

  The measurement that will be made later can be made more difficult or unusable depending on the needs.

  It is also found, with the known devices, that the aerosols deposited can be resuspended in the air following a sudden change in the environment.

  2870938 2 This obviously distorts the measurement.

  To remedy this, the collection devices then comprise a suction device.

  This suction device obviously has the effect of modifying the collection because it creates a depression at the collection receptacle which then modifies the kinetics of aerosols.

  The object of the invention is to remedy, in particular, the aforementioned drawbacks.

  To this end, the invention relates to an aerosol collection device comprising a vertical axis receptacle open on top and whose conical base is open from below so that the aerosols are deposited on a collecting surface of a support, this device being characterized in that around the base of the receptacle is constituted a chamber whose lower wall is at a distance from the lower end of the receptacle, this lower wall having an orifice against which the support plate intended to receive aerosols.

  The invention will be better understood using the following description given by way of non-limiting example with reference to the accompanying drawings which show schematically: FIG. 1: a partial view in vertical section of a collection device FIG. 2: a view of the loading / unloading mechanism, FIG. 3: a view of a detail of FIG. 2, FIG. 4: an overall view of a collection device.

  Referring to the drawings, there is shown a device 1 for collecting aerosols.

  This collection device 1 is intended for the study of sedimentary aerosols, that is to say those which are deposited naturally on the site of implantation of the collection device.

  Conventionally, this collection device 1 comprises a receptacle 2 of vertical axis open on the top and whose conical base is open from below so that the aerosols can be deposited on a collecting surface 3A of a support 3.

  The collection device 1 comprises, under the receptacle, an automatic device 4 for loading and unloading supports 3 intended to receive the aerosols and a means 4A for possibly programmable control of this loading / unloading device.

  2870938 3 This device 4 loading / unloading media and can multiply the measurements without the need for human intervention on site.

  We can thus make more numerous measurements over time and in particular highlight periods of the day more favorable to the flight of these 5 aerosols.

  The collection device 1 will therefore comprise at least one means 5 for storing standby media and, secondarily, storage means 6 for the media used for subsequent analysis.

  Advantageously, the loading / unloading device 4 is coupled with a means 7 for quantitative and / or qualitative measurement of the aerosols deposited on the support 3, such as a weighing means 7.

  This loading / unloading device 4 will then move the sample placed under the receptacle 2, for example towards the weighing means.

  The result of the weighing will be: - either stored on site in a memory, or sent to a central station via wireless or wired communication means.

  Advantageously, the weighing means 7 is carried by a support member 70, which is mechanically isolated from the vibrations of the receptacle 2 and other materials.

  For example, the support member 70 will be held by vibration isolators, such as rubber blocks or the like.

  This is essential if one wishes to make a measurement by weighing in a hostile environment.

  Advantageously, the loading / unloading device 4 as well as the measurement means are housed in a so-called airtightness-resistant chamber 40 (wind, rain, etc.).

  Furthermore, these elements are carried by a plate 20 mechanically uncoupled from the receptacle 2 so that the movements of the receptacle do not affect the aforementioned elements.

  The plate 20 can thus be carried by another support or be connected to the support of the receptacle 2 by dampers.

  Preferably, the collection device 1 comprises a vibrator 8 acting on the receptacle 2 in order to drop the aerosols deposited on the wall of the receptacle 2. This vibrator 8 can be activated periodically but, preferably, will always be active.

  Of course, when loading media 3 or unloading, it can be made inactive as well as during the weighing operation.

  Advantageously, the collection device 1 comprises a rain detector 9, which rain sensor is connected to the control means 4A mentioned above.

  For example, this rain detector 9 will work by measuring the resistivity.

  Advantageously, this rain detector 9 is located inside the receptacle 2 and, preferably, at the bottom of the receptacle just above the evacuation.

  In the example shown, this detector is in the form of two plates cross and thus occupying the bottom of the receptacle.

  These pads are perpendicular to the collecting surface 3A of the support 3 when it is in place.

  Printed conductive elements are thus connected to the measurement electronics.

  When a drop of water falls on the printed conductors, it makes contact between the two conductors which triggers a series of operations such as those provided for loading.

  A heater 10 is advantageously provided in particular in the area of implantation of the rain sensor so that the ambient humidity will not trigger the detector and only the rain will be able to produce a triggering signal.

  This detector 9 is connected to the control means 4A so that, when the rain is detected, the support 3 receiving the aerosols can be moved, for example, to make a measurement by weighing with an indication signaling this event.

  During this manipulation, following a rain detection, the loading device 4 can: either wait for the rain sensor to indicate that the rain has stopped to put back a support 3 in place, or set up a specific support for the rain.

  In the embodiment chosen, under the receptacle, there is provided a hole 11 for evacuation in the plate 20 receiving the support for dry aerosols.

  Under this hole, can be arranged a bottle for collecting rainwater loaded with aerosols or an evacuation pipe.

  According to the invention, around the base of the receptacle 2, is constituted a chamber 12 whose lower wall 12A is located at a distance from the lower end of the receptacle 2, this lower wall then having an orifice 12B against which the support plate intended to receive the aerosols when the support has to be put in place.

  When the support is pressed against the orifice, the chamber is not subjected to the depression that could be created in the receptacle and would fly aerosols already deposited.

  This chamber 12 extends under the receptacle and houses a portion of the lower cone of the receptacle.

  The support 3 consists of a plate formed of a conductive material to prevent electrostatic effects.

  This support 3 is applied under the chamber to close it. An actuator 30 allows to apply it under the receptacle.

  To avoid during unloading that the aerosols disperse, the support zone 3A of the support 3 against the receptacle 2 is bordered by a relatively wide circular groove 3B with respect to the distance of displacement of this support between its pressed position against the face bottom of the chamber and its position apart.

  For a displacement value of the order of half a millimeter, the width of the groove will be of the order of five millimeters.

  We will now describe in more detail the loading / unloading device that is used in the exemplary embodiment.

  A fixed platen 20 extends both under the receptacle and the media storage device waiting.

  In the zone under the receptacle 2, the plate 20 is interrupted and it is replaced by a table 21 movable vertically by means of one or more actuators and this mobile table 21 is pierced with a hole 11.

  2870938 6 This table is used to lift the support to apply against the chamber 12 surrounding the base of the receptacle 2.

  In the event of rain, the support being removed, the lifting table is pressed against the chamber and this lifting table has an orifice for discharging the rainwater to a container or to the outside.

  This avoids rising flows.

  The upper face 21A of the central part of this lifting table 21 will preferably be concave.

  The storage device 5 is a simple tube of vertical axis whose base is kept at a distance from the plate 20.

  The support 3 situated at the bottom of the stack of supports 3 rests on a movable stop 23.

  A moving part 14, called the driving part, located above the plate 20 is positioned under the storage device 5 and receives the support when the movable stop 23 is removed.

  This driving part 14 slides the support 3 from the storage device 5 to an area under the receptacle 2 and a lifting table 21 then raises said support 3 and press against the chamber 12.

  The upper surface of the support is at a distance from the lower end 2A of the conical receptacle.

  When the moment of the measurement has arrived, the lifting table 21 is lowered so that the driving part 14 can take over the movement of the support to drive it towards the measuring device such as the scale plate.

  Then, the driving device brings the support 3 to a storage area 6.

  In the example shown, it is a simple tube 6 placed under the support plate 20.

  Note that the driving part 14 comprises a notch 24 in order to reposition correctly.

  The notch cooperates with a contactor 25.

  In the example reproduced in the drawing, the driving part 14 moves on a sector first in a counter-clockwise direction from the storage device of the unused supports to the lifting table and then in the opposite direction towards the system. weighing then to the storage area of the media used.

  In the present case, there is the presence of a counter plate 26 above the plate so that the support is guided in translation and protected from the outside.

  The driving part 14 has a light for receiving the support 3.

  Other loading / unloading systems 4 are of course conceivable.

8 2870938

Claims (14)

  An aerosol collection device comprising a vertical axis receptacle (2) open at the top and whose conical base is open from below so that the aerosols can be collected on a collecting surface (3A) of a support (3), this collecting device being CHARACTERIZED in that around the base of the receptacle (2) is constituted a chamber (12) whose lower wall (12A) is at a distance from the lower end of the receptacle ( 2), this lower wall (12A) having an orifice (12B) against which the support for receiving the aerosols is slotted.   2. A collection device according to claim 1 characterized in that it comprises a heating (10).   3. A collection device according to claim 1 or 2 characterized in that it comprises a detector (9) rain, which rain detector is connected to a means (4A) for controlling a loading / unloading device.   4. The collection device according to claim 3 characterized in that the detector (9) of rain is located inside the receptacle (2) and, preferably, at the bottom of the receptacle just above the discharge.   5. A collection device according to any one of claims 1 to 4 characterized in that it comprises a plate (20) and, in the area below the receptacle, the plate (20) is interrupted and is replaced by a table (21) movable vertically by means of one or more actuators (30), this table (21) movable being pierced with a hole (11).   6. Collecting device according to claim 5 characterized in that the upper face (21A) of the central portion of the lifting table (24) is concave.   7. A collection device according to any one of claims 1 to 6 characterized in that it comprises a vibrator (8) acting on the receptacle in order to drop the aerosols deposited on the wall of the receptacle (2).   8. A collection device according to any one of claims 1 to 7 characterized in that it comprises, under the receptacle, an automatic device (4) for loading / unloading supports (3) intended to receive the aerosols and a 9 2870938 means (4A) programmable control of this device loading / unloading.   9. The collection device according to claim 8 characterized in that the device (4) for loading / unloading and the measuring means are housed in a chamber (40) called airtight protection to atmospheric disturbances.   10. The collection device according to claim 8 characterized in that the device (4) for loading / unloading and the measuring means are carried by a platen (20) uncoupled mechanical receptacle (4).   11. A collection device according to claim 8 characterized in that the device (4) for loading / unloading is coupled with a means (7) of quantitative and / or qualitative measurement.   12. A collection device according to claim 11 characterized in that the means (7) weighing is carried by a support (70), which is mechanically isolated from the vibration of the receptacle (4) and other materials.   13. The collection device according to claim 1 characterized in that the bearing area of the support (3) against the receptacle (2) is bordered by a groove (3B) relatively wide circular relative to the distance of the displacement of this support (3) between its pressed position against the underside of the chamber and its spaced apart position.   14. A collection device according to claim 13 characterized in that the support (3) is constituted by a plate formed in a conductive material to prevent electrostatic effects.