FR3061958A1 - METHOD FOR COLLECTING FILTRATION, AND ANALYSIS OF PARTICLES AND MICROORGANISMS IN AIR AND DEVICE FOR IMPLEMENTING THE SAME - Google Patents

Abstract

The present invention aims at providing a method and an installation for detecting particles and microorganisms contained in a volume of air, which are more efficient and more practical to implement than the methods currently used and in particular the concentration method. centrifugation and dissolution in a liquid solution. The method consists in taking a determined volume of air in the environment or in a confined space which is difficult to access by sampling means (100) consisting of a mobile structure (101) with wheels (109) joining suction means (102), guiding means (103) (106) (108) and filter means consisting of a "filter block" (107) containing a "filter drawer" (104) receiving a "mobile filter" Dry or wet (105) itself consisting of an "absorbent molecular capture substrate" (112) to retain the passage of air, the particles and microorganisms contained. This process differs from current processes in that the wet or dry "mobile filter" (105) is directly analyzed in the laboratory after filtration, without any intermediate processing of the particles such as heating, centrifugation and other treatment.

Description

Holders): EXPERTON JACKY.

O Extension request (s):

® Agent (s): EXPERTON JACKY.

® PROCESS FOR SAMPLING FILTRATION, AND ANALYSIS OF PARTICLES AND MICRO-ORGANISMS CONTAINED IN AIR AND DEVICE FOR IMPLEMENTING IT.

FR 3 061 958 - A1

The present invention aims to propose a method and an installation for detecting particles and microorganisms contained in an air volume, which are more efficient and more practical to implement than the methods currently used and in particular the method of concentration by centrifugation and dissolution in a liquid solution. The method consists in withdrawing a determined volume of air from the environment or from a confined space that is difficult to access by sampling means (100) constituted by a mobile structure (101) with casters (109) joining together suction means. (102), guide means (103) (106) (108) and filtration means constituted by a “filter block” (107) containing a “filter drawer” (104) receiving a “filter- mobile >> dry or wet (105) itself consisting of an "absorbent molecular capture substrate" (112) to retain the passage of air, particles and microorganisms contained. This method differs from current methods by the fact that the dry or wet "mobile filter" (105) is directly analyzed in the laboratory after filtration, without any intermediate operation of treatment of the particles such as heating, centrifugation and other treatment.

METHOD FOR SAMPLING, FILTRATION AND ANALYSIS OF PARTICLES AND MICROORGANISMS CONTAINED IN AIR AND DEVICE FOR IMPLEMENTING SAME.

The present invention relates to a method and a mobile electromechanical device intended for the sampling and filtration of particles and microorganisms present in the ambient air and their dry analysis in the laboratory without recourse to intermediate operations or mixing with an absorbent solute.

The method and its device are concerned with the treatment of particles and microorganisms in suspension in a volume of ambient air and not with the exclusive aspiration of particles deposited on the ground as a vacuum cleaner would do, in particular in environment and environment. '' inside free premises or in a confined atmosphere such as the inside of a sealed container, a vehicle such as a truck, plane, boat, etc.

In general, the device for implementing the method of the invention brings together, in a single mobile support, means of suction and orientation of the flows towards filtration means such as at least one collecting filter capable of concentrate and collect molecules.

It is known that the ambient air in a free environment is most often charged with volatile organic compounds most often emitted by transport vehicles, for example aliphatic and aromatic hydrocarbons, alkenes or even aldehydes, or by the evaporation of fuels such as benzene, toluene, xylene etc. Other compounds also come from industrial activities, such as alcohols, esters, ketones, aldehydes, chlorinated solvents etc., to which are added compounds generated by agriculture and its spreading or domestic activities .

The metrology of volatile compounds faces several difficulties including: the great diversity of concentration, the plurality of chemical families, the representation of the sampling to be analyzed, the diversity of sampling, transfer and analysis techniques, transport and storage of samples etc. The sampling method, the analysis technique and the calibration method are criteria to be taken into account to quantify the volatile compounds.

The technique for sampling volatile compounds is determined from the physico-chemical properties of the compounds as well as the nature of the medium to be sampled.

Two methods of sampling are distinguished more generally: direct sampling without concentration and direct sampling with concentration.

The method of sampling without concentration consists in filling a container such as for example a bag or an ampoule, it can only be used if the detection limits of the compounds are compatible with analytical systems, this method of sampling is less and less used taking into account the possibilities of rapid evolution of the gases before analysis, the volatile compounds being able to be absorbed on the walls of the container. The container is filled either by direct suction or by creating a vacuum to let the air to be treated.

The purpose of the concentrated sampling method is to concentrate the molecules present in low content in the air, before analysis. This concentration is most often done by absorption in an absorbent liquid solution. The volume of air to be analyzed is drawn in through a glass or steel tube. The absorption and desorption capacity of the support depends on the nature and the physico-chemical properties of the compounds studied, on the nature and the physico-chemical properties of the absorbent, on the temperature and the relative humidity of the medium. and withdrawal conditions (flow, duration, etc.).

By patent WO2004 / 108880, the collection of particles and microorganisms present in the ambient air has been proposed by separation by sucking air into a cylindrical enclosure in which said particles or microorganisms transported by the air are rotated around the axis of the enclosure and are separated from the air by centrifugation on the inner wall of the enclosure, a liquid is then injected on the inner walls of the enclosure so as to recover at the bottom thereof a solute comprising the particles collected to be analyzed. This method therefore involves dissolution in an absorbent liquid medium, followed by a chemical reaction between this medium and the desired compound. This results in the formation of a stable, non-volatile compound, such as a characteristic precipitate, which can then be easily assayed. This method makes it possible to effectively trap, then analyze, polar compounds which are difficult to access because they are not very absorbable or little desorbable, but also has certain drawbacks.

By patent FR 2 956 211, a method and an installation for detecting at least one target material such as a narcotic material or an explosive material have been proposed, said method consisting in circulating air taken from a volume confined air in which the presence of at least one target material is suspected to be present, through a capture substrate which is heated so as to release the odorous molecules coming from said target material which is then directed towards the nose of a trained dog.

The application of this method involves an installation comprising means for withdrawing a volume of air inside a volume of confined air, means for heating the substrate and guide means for guiding the molecules. odorants revealed towards the dog's nose. If the efficiency of this process and its installation seems indisputable, said installation makes two elements cooperate with each other, quite independent of each other and used separately from each other; on the one hand, sampling means consisting of a carriage associating the suction means and the filtration means, in particular the capture substrate, and on the other hand means for heating said capture substrate associated with means for guiding the odorous molecules revealed towards the muzzle of the detector dog.

Unlike the methods and device described, the present invention differs significantly by the treatment reserved for the volumes of air withdrawn. In fact, the aim of the present invention is to propose a detection method and installation which are more efficient and more practical to implement, these advantages having been confirmed by comparative tests carried out by the school of mines at Alès. (30319) in 2015 between the method of concentration by centrifugation and dissolution in a liquid solution currently the most frequently used and the method by aspiration and filtration of the present patent, showing a capacity of recovery of microorganisms high and much higher than that of other processes.

To this end, the method of the present invention uses sampling means close to those described in the methods described above, but the treatment of the sampled air differs significantly from the aforementioned methods, in that the sampled air is in no way subjected to a rise in temperature with the aim of revealing the odorous molecules subjected to canine detection and the sampled air is also not subjected to centrifugation inside an enclosure so that the particles and micro- organisms are plated on the internal walls of said enclosure and concentrated in an absorbent liquid.

The present invention therefore relates to a method and a mobile installation comprising on a single structure, all the means of taking a volume of air to be analyzed by direct aspiration and according to precise criteria (speed, duration etc.), in the ambient air or in the volume of air from confined and / or inaccessible spaces, to orient said volume of aspirated air towards a filter support block comprising at least one absorbent molecular capture substrate, to retain particles and micro- organisms and release the air into the environment after filtration. Thus the process is characterized in that it comprises stages according to which:

- A volume of ambient air laden with particles or microorganisms is taken up by suction in a free or confined environment,

- The charged air thus withdrawn is directed from the suction access called "suction point" to filtration means.

- We analyze in the laboratory and directly the particles and microorganisms present on the capture substrate of the filtration means and this without prior concentration by centrifugation of the sampled air, without using any absorbent liquid and without raising the temperature of the substrate of capture of the filtration means.

The invention also relates to a sampling and filtration installation, characterized in that it comprises:

- mobile sampling means comprising functionally associated functionally on the same structure provided with wheels;

- Suction means to draw air from a volume of air,

- Means for guiding said air sucked from the sampling place towards filtration means.

- Support means to maintain and center at least one mobile and interchangeable filtration means of the aspirated air.

- Movable and interchangeable means of filtering the intake air.

According to additional advantageous characteristics of the process or of the installation according to the invention, taken in isolation or in any technically possible combination,

- The mobile sampling means consist of a mobile structure, preferably metallic, steerable and provided with wheels or ambulatory and easily transportable by hand or man's back, operatively associated with said same structure, suction means of the air, means for guiding the aspirated air and means for filtering said aspirated air.

- The air suction means consist of an air suction turbine powered by electrical energy and the inlet of which is connected to a flexible hose, to draw a volume of air to be treated by suction 'interior of an ambient air volume;

- The means for guiding the intake air consist of a flexible tube called a "guide tube", one end of which is provided with an "interchangeable probe tip" and the other end of which is fitted with a "mechanical connector" , Γ "interchangeable probe tip" to be inserted by interstices in the confined and / or closed air volumes and the "mechanical connector" to be associated for example by screwing or snap-fastening in the center of the upper plane of the support support means and centering the filtration means, so as to direct the air withdrawn from the sampling location towards the center of the filtration means;

- The support means for centering and centering the filtration means consist of a preferably metallic block called a “filter block” to receive inside a drawer called a “filter drawer”, said “filter drawer” being designed and arranged to receive at least one mobile and interchangeable means of filtration;

- The mobile and interchangeable filtration means consist of at least one molecular filter known as a "mobile filter", preferably circular, comprising an absorbent molecular capture substrate to retain particles and microorganisms and to be removed for analysis in the laboratory.

The device described here in the specific case of a specific application, is in no way limited to this single application, it can be implemented in other applications and according to other manufacturing methods.

The following description with reference to the accompanying drawings by way of nonlimiting examples will allow a better understanding of how the invention can be put into practice.

Figure 1 is a general perspective view of the entire installation of the process, sampling and analysis.

FIG. 2 is a perspective view of the sampling of a volume of air to be analyzed from a volume of confined air.

Figure 3 is a view of the analysis mode without recourse to concentration by centrifugation and mixing with a liquid absorbent medium.

FIG. 4 is a perspective view of a mobile and interchangeable filtration means, to be analyzed as it is and without any other intermediate operation in the laboratory.

Figure 5 is a front view of a manual concentration device for sampling in an open environment.

According to the preferred embodiment of the invention, the means for sampling the volume of air to be analyzed consist of a “movable steerable structure” (100), preferably metallic, provided with “orientable rollers” (109), functionally associated with air suction means called "turbine body" (102), with means for guiding the aspirated air called "guide pipe" (106) and with filtration means called "block filter ”(107) of said intake air. (See Fig

1)

According to the preferred embodiment of the invention, the suction means of the volume of air to be analyzed are constituted by a "turbine body" (102) driven by electrical energy, the inlet of which is connected to a "pipe guide ”(106), to suck a determined volume of air inside a volume of ambient air. (See Fig 1)

According to the preferred embodiment of the invention, the suction means of the volume of air to be analyzed are constituted by a "turbine body" (102) driven by electrical energy, the inlet of which is connected to a "pipe guide ”(106), for sucking a limited and concentrated volume of air inside a“ concentration cone ”(115) of determined volume, said“ concentration cone ”(115) being used for certain withdrawals in the environment or in free space inside demarcated premises. (See Fig 5).

According to the preferred embodiment of the invention, the means for guiding the aspirated air consist of a "guide pipe" (106), one end of which is provided with an "interchangeable probe tip" (108) and the other end is equipped with a "mechanical connector" (103), Γ "interchangeable probe tip" (108) to be inserted by interstices in the volume of confined and / or closed air (113) and the "connector mechanical ”(103) to be associated for example by screwing or snapping in the center of the upper plane of the“ filter block ”(107) of the“ movable airship structure ”(100). (See Fig 1)

According to the preferred embodiment of the invention, the support means for holding and centering the filtration means consist of a preferably metallic block called a “filter block” (107), receiving inside a drawer called “ filter drawer ”(104), said“ filter drawer ”(104) being designed and arranged to receive at least one mobile and interchangeable means of filtration, known as“ dry or wet “mobile filter” (105). (See Fig 1 and 4).

According to the preferred embodiment of the invention, the movable and interchangeable filtration means consist of at least one molecular filter called dry or wet “mobile filter” (105), preferably circular and comprising a “molecular capture substrate absorbent ”(112) for example retained in a frame called“ substrate frame ”(111), for collecting the particles and microorganisms present in the volume of air sucked in, said dry or wet“ mobile filter ”(105) being removed from the "filter drawer" (104) after aspiration, to be examined directly and without any other intermediate operation by "laboratory means" (200). (See Fig 1,3 and 4).

According to the preferred embodiment of the invention, the dry or wet “mobile filter” (105) (quartz or gelatin), preferably circular, comprises a “absorbent molecular capture substrate” (112) with a surface and a thickness which varies according to the types of particles and micro-organisms to be collected, retained in a “framework substrate” (111) of the same shape and dimensions to allow the interchangeability of the dry or wet “mobile filter” (105) in the “filter drawer” ( 104) of the “filter block” (107). (See Fig 1 and 4).

According to the preferred embodiment of the invention, the method consists in taking a determined volume of air from a confined and hardly accessible space (113), according to precise criteria of duration and speed adapted and compatible with the "substrate of absorbent molecular capture ”(112) making up the“ wet or dry ”mobile filter (105) contained in the“ filter drawer ”(104) of the filter block (107), to guarantee optimum filtration of the particles and microorganisms contained in said volume of filtered air. (See Fig 1 and 2).

According to the preferred embodiment of the invention, the sampling of the volume of air in a confined and / or difficult to access space (113) is carried out by moving the "movable airship structure" (100) constituting the sampling means, to place it near said space (113), in order to introduce therein through any gap, Γ “interchangeable probe tip” (108) of the free end of the “flexible pipe” (106). Once I "interchangeable probe tip" (108) introduced into the space to be treated (113), the "turbine body" (102) is put into service. (See Fig 2)

According to the preferred embodiment of the invention, the sampling of the volume of air in the environment or in the volume of ambient air contained in a determined space is carried out using a "concentration cone" (115) whose internal volume (117) is determined and known, associated with the means for guiding the "movable steerable structure" (100) of the installation for implementing the method, in particular the "flexible pipe" (106). (See Fig 5).

According to the preferred embodiment of the invention, the volume of air drawn by suction from the environment or from a confined and difficult to access space (113) is guided by the "guide pipe" (106), towards the "Filter block" (107) in the "filter drawer" (104) which has been placed a dry or wet "mobile filter" (105). The “absorbent molecular capture substrate” (112) constituting the dry or wet “mobile filter” (105) is then traversed by the aspirated air and retains the particles and microorganisms contained in said volume of air, the volume filtered air free of its particles and microorganisms being released into the environment. (See Fig 1 and 4).

According to the preferred embodiment of the invention, as soon as the suction has been carried out, the "turbine body" (102) of the "steerable mobile structure" (100) is put out of service, Γ "interchangeable probe tip" (108) is removed from the sampled space, the "filter drawer" (104) of the "filter block" (107) is opened and the dry or wet "mobile filter" (105) is extracted to be transferred without another intermediate operation at the analysis laboratory. The laboratory then proceeds by means of its equipment (200) to the direct examination of the dry or wet “mobile filter” (105), without subjecting the “absorbent molecular capture substrate” (112) to the slightest rise in temperature, without centrifuging the particles and microorganisms and / or mixing with any liquid, to precisely determine the types of particles and microorganisms collected as well as their dosage. (See Fig 1 and 3).

Claims (8)

CLAIMS. 1, - Process for sampling, filtration and analysis of particles and microorganisms contained in a determined volume of air, characterized in that the volume of air to be analyzed is sampled by aspiration from the environment or from the ambient air of a determined space, free or confined and / or difficult to access (113), oriented by guide means and in particular a "guide pipe" (106), towards filtration means collecting by simple passage of air through a Dry or wet "mobile filter" (105) particles and microorganisms contained in the aspirated air, said dry or wet "mobile filter" (105) being removed from a "filter drawer" (104) of a "Filter block" (107) of a "movable steerable structure" (100) after filtration, to be directly and without any other intermediate operation, subject to examination and analysis in the laboratory. 2, - Process for sampling, filtration and analysis of particles and microorganisms contained in an air volume according to claim 1, characterized in that the volume of air to be analyzed is sampled according to precise criteria of suitable duration and speed and compatible with the “absorbent molecular capture substrate” (112) making up the dry or wet “mobile filter” (105) contained in a “filter drawer” (104) of a “filter block” (107) of a "Movable airship structure" (100), to guarantee optimum filtration of the particles and microorganisms contained in said volume of filtered air. 3, - Method for sampling, filtration and analysis of particles and microorganisms contained in an air volume according to claims 1 and 2, characterized in that the sampling of the volume of air to be analyzed in the environment or in the volume d ambient air contained in a determined space, is produced by using a "concentration cone" (115) whose internal volume (117) is determined and known, associated with the guide means of the "movable airship structure" (100) of the device for implementing the method, in particular a "flexible pipe" (106). 4, - Method for sampling, filtration and analysis of particles and microorganisms contained in an air volume according to claims 1 and 2, characterized in that the suction of the air volume to be analyzed having been carried out, the "drawer- filter ”(104) of the“ filter block ”(107) is open and the dry or wet“ mobile filter ”(105) is extracted to be transferred directly and without any other intermediate operation to the analysis laboratory, the latter then proceeding by means of its equipment (200) to direct and dry examination of the dry or wet “mobile filter” (105), without subjecting the “absorbent molecular capture substrate” (112) to the slightest rise in temperature, without centrifugation particles and microorganisms and / or mixture with any liquid. 5. - Device for implementing the process of sampling, filtration and analysis of particles and microorganisms contained in an air volume according to claim 1, characterized in that the suction means consist of a "body of turbine ”(102) driven by electrical energy and the inlet of which is connected to a“ guide pipe ”(106), for sucking a concentrated and limited volume of air inside a“ concentration cone ”( 115) of determined volume, said “concentration cone” (115) being used for certain samples taken from the environment or from free space inside demarcated premises. 6. - Device for implementing the process of sampling, filtration and analysis of particles and microorganisms contained in an air volume according to claim 5, characterized in that the means for guiding the sucked air consist of: 'a "guide pipe" (106) one end of which is provided with an "interchangeable probe tip" (108) and the other end of which is fitted with a "mechanical connector" (103), Γ "interchangeable probe tip" (108) to be inserted by interstices in the confined and / or closed air volume (113) and the "mechanical connector" (103) to be associated for example by screwing or snap-fastening in the center of the upper plane of the "block filter ”(107) of the“ movable steerable structure ”(100). 7. - Device for implementing the process of sampling, filtration and analysis of particles and microorganisms contained in an air volume according to claims 1, 2, and 4, characterized in that the mobile and interchangeable filtration means consist of at least one circular filter called "mobile or dry" or wet filter (105) comprising a "absorbent molecular capture substrate" (112) retained in a frame called "substrate frame" (111), to collect the particles and microorganisms present in the aspirated air, said dry or wet "mobile filter" (105) being removed from the "filter drawer" (104) of the "filter block" (107) after suction, for direct examination and without any other intermediate operation by laboratory means (200). 8.- Device for implementing the process of sampling, filtration and analysis of particles and microorganisms contained in an air volume according to claim 7, characterized in that the dry or wet "mobile filter" (105) circular includes a “absorbent molecular capture substrate” (112) with a variable thickness and surface depending on the types of particles and micro-organisms to be collected, retained in a “substrate-frame” (111) of the same shape and dimensions to allow the interchangeability of the dry or wet "movable filter" (105) in the "filter drawer" (104) of the "filter block" (107). 1/3