FR3023563A1 - PORTABLE DEVICE FOR DETECTING THE PRESENCE OF ELEMENTS HAVING GLACOGENIC ACTIVITY IN AT LEAST ONE SAMPLE - Google Patents

Abstract

The present invention relates to a portable device for detecting the presence of elements having a gelogenic activity in at least one sample (E). The portable device (1) comprises a refrigeration unit (2) comprising - a chamber (3), thermally insulated, - means (4) for refrigerating said chamber (3), - means (5) for measuring temperature, - means (6) for setting a target temperature within said chamber (3), - means (7) for the autonomous power supply of said refrigeration unit (2). According to the invention, the chamber (3) contains at least two locations (8) which are each adapted to receive one of said samples (E), and the refrigeration unit (2) further comprise means (6) for signal the achievement of said target temperature.

Description

TECHNICAL FIELD TO WHICH THE INVENTION RELATES The present invention relates to portable devices for detecting the presence of elements having a gelogenic activity.

BACKGROUND TECHNOLOGY Extra pure water can be maintained undercooled down to -40 ° C. However, in nature, water contains many elements with "ice-forming" activity, commonly referred to as "crystallization nuclei" or "ice nucleuses", that is, elements causing a supercooling breakup of the water at negative temperatures, likely to be relatively close to 0 ° C. Ice nucleuses have diverse and important roles in the environment.

In particular, by causing icing, ice nuclei trigger important processes for the formation of rain and snow, but also frost damage to overwintering plants and organisms. The detection of these ice nucleuses in the environment thus makes it possible to provide various advice, for example to manage the risk of frost damage or to enrich environmental sources of microorganisms that can be transported to clouds to contribute to the atmospheric process. Certain particles of biological origin (microorganisms, plant tissues, organic matter on soil particles, for example) are capable of causing this setting in ice of water at negative temperatures close to 0 ° C (advantageously between -10 ° C). ° C and 0 ° C). In the field of plants, many icogenous nuclei meet, in particular bacterial strains which constitute an excellent initiator of setting in ice from -2 ° C such as Pseudomonas syringae. To detect the presence of these icogenous nuclei, it is interesting to be able to implement portable devices intended to be brought into the field. Such a portable device is for example described in the document Neuner et al. ("Ice formation and foliar frost resistance in attached and excised shoots of seedlings and adult trees of Nothofagus menziesii", New Zealand Journal of Botany, 35: 2,221-227). The corresponding portable device therefore comprises a refrigerated chamber of which: a first end is open so as to allow the introduction of a plant sample, and a second end opposite is equipped with refrigeration means comprising a Peltier module whose cold face is associated with ventilation to generate a flow of air in said refrigerated chamber. However, such a portable device is relatively limited in that it allows the detection of the presence of ice nucleuses in a single sample, which is in solid and large form. OBJECT OF THE INVENTION In this context, the present invention relates to a portable device for detecting the presence of elements having a gelogenic activity in at least one sample. This portable device comprises a refrigeration unit which comprises: a thermally insulated chamber in which said sample or samples are intended to be introduced, means for refrigerating said chamber, means for measuring the temperature; within said chamber; means for setting a target temperature within said chamber, said target temperature being adapted for detecting the presence of elements having ice-forming activity in said at least one sample; means for the autonomous power supply of said refrigeration unit. And in accordance with the present invention, said chamber contains at least two locations each of which is adapted to receive one of said samples; and said refrigeration unit further comprises means for signaling the attainment of said target temperature. Such a portable device has the advantage of allowing a detection of the presence of elements having a gelogenic activity, simultaneously in several samples. This portable device also has the advantage of being autonomous, transportable and low energy consumption. Other advantageous characteristics, which can be taken in combination or independently of each other, are developed below: the locations are, on the one hand, formed in a thermal conductive member located in the chamber (adapted for refrigeration of said locations, especially by thermal conduction) and, secondly, adapted to each receive a container containing one of said samples; in this case, the thermal conductive member advantageously rests on the refrigeration means; the locations each have dimensions that are adapted, with play, to receiving a microtube; - the chamber is delimited, in part, by the refrigeration means; in this case, preferably, the refrigeration means comprise a Peltier module which comprises: - a cold face, forming at least a part of one of the walls of the chamber, and - a hot face, external to said chamber and coupled means for heat dissipation; the volume of the chamber is between 100 and 200 cm 3, and said chamber has a bottom surface of between 30 and 50 cm 2 and a height of between 3 and 4 cm; the cold face of the Peltier module extends over an area of between 80 and 90 cm 2; the chamber is devoid of means for mixing the air within said chamber; the portable device further comprises timing means adapted to shift the activation of the means to signal the attainment of the target temperature for a certain time; the portable device comprises a pre-conditioning unit comprising: a thermally insulated chamber in which said sample or samples are intended to be introduced; means for refrigerating said chamber; means for measuring the temperature; temperature within said chamber; means for setting a target temperature within said chamber, said target temperature being higher than the target temperature set in the refrigeration unit; means for the autonomous power supply of said preconditioning unit.

The present invention also relates to a portable installation for detecting the presence of elements having a gelogenic activity in at least one sample, comprising: - a portable device according to the invention, and - a unit for storing accessories adapted to the preparation samples and / or the processing of the data acquired by the implementation of said portable device. According to an advantageous characteristic, the portable installation comprises: means for recording and / or analyzing data, data transfer means, and geolocation means. According to another advantageous characteristic, the portable installation comprises means for its movement on the ground and gripping means for its maneuver by a user.

The present invention also relates to a method for detecting the presence of elements having a gelogenic activity in at least one sample, by means of a portable device according to the invention, consisting in: - preparing said sample or samples by suspending of elements having an ice-forming activity potentially present in a medium of interest by means of a sampling liquid initially free of such elements having a gelogenic activity, - disposing said sample or samples in the locations of the chamber of the unit refrigerating said portable device, - controlling the refrigeration means of the refrigeration unit of said portable device so as to reach the target temperature suitable for taking ice samples containing the elements having an ice-forming activity, and - once said target temperature reached, to be determined, on the one hand, the sample or samples t the sample taken in ice, corresponding to the sample (s) containing elements having a gelogenic activity and, on the other hand, the sample (s) whose sample liquid remains in a liquid state, corresponding to the (x) Sample (s) lacking elements with ice-forming activity. According to a particular embodiment, for the detection of elements having a biogenic activity of biological origin, the target temperature is advantageously between 0 ° C. and -15 ° C., preferably between -6 ° C. and -9 ° C. vs. According to another particular embodiment, the sample or samples prepared are each packaged in a container which is attached in one of the locations; and the height of the sample is adjusted to be less than or equal to the depth of the associated location. DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT The present invention will be further illustrated, without being limited in any way, by the following description of a particular embodiment in relation to the appended figures in which: FIG. 1 is a diagrammatic view, according to a vertical cutting plane, a refrigeration unit constituting a portable device according to the invention; FIG. 2 represents the refrigeration unit according to FIG. 1, in which its various structural elements are dissociated from one another; - Figure 3 illustrates the refrigeration unit of Figures 1 and 2, exploded and in perspective; - Figure 4 shows schematically a portable installation in which is introduced the portable device according to the invention. The portable device according to the invention, as shown in FIGS. 1 to 3, is designed to detect the presence, in at least one sample (advantageously in several samples), of elements having a gelogenic activity.

The portable device according to the invention makes it possible in particular to detect, in the field, the presence of elements having a glazing activity, in an autonomous and compact manner.

Definitions By "portable" device is preferably meant a device adapted to be easily transported by an individual. By "elements having a glacogenic activity" is meant in particular any grain of matter that promotes the formation of ice crystals in liquid water. In particular, any element capable of causing a supercooling rupture of the liquid water at negative temperatures close to 0 ° C. is understood. By "negative temperatures close to 0 ° C" is meant in particular temperatures between -15 ° C and 0 ° C, preferably between -10 ° C and 0 ° C, preferably between -9 ° C and - 6 ° C, more preferably between -8 ° C and -7 ° C. Such elements having a glacogenic activity are still commonly referred to, and indifferently throughout the present description, under the names of "crystallization nuclei" or "ice nucleuses".

Such gelogenic nuclei may be of biological origin, such as microorganisms, debris on the surface of the leaves, particles recovered from the soil, air or water. In the case of a bacterial origin, it is for example a bacterial strain called "ice-forming bacteria" which is selected from the following species: Pseudomonas syringae, Pseudomonas viridiflava or Xanthomonas campestris pv translucens. The ice-forming activity could also be of fungal origin, due in particular to the spores of certain rusts, or other fungi. In the context of the present invention, the portable device advantageously allows the detection, in a sample, of an element or a mixture of elements having a gelogenic activity for a temperature less than or equal to a determined target temperature. By "samples" to be analyzed, advantageously means any sampling (liquid or solid in a sample liquid) in the environment, in a liquid state at a temperature above 0 ° C, that is to say for example: a sample of ice-forming nuclei (for example of ice-forming microorganisms) possibly present on the surface of a support, for example a plant or part of a plant (leaf in particular), or biological products, such as tissues; plants (leaves, buds, flowers, fruits, bark, etc.) or insects, pollen, spores, litter, to detect the presence of intrinsic ice-forming activity, or - samples of water in the environment, for example lake, river, irrigation water. By "detecting the presence of elements having a glacogenic activity in a sample", is meant in particular the approach of discrimination / distinction of the samples with respect to, between: - a sample devoid of ice-forming nuclei, that is to say say a sample in the liquid state at a target temperature, and a sample containing ice nucleuses, that is to say a sample taken in ice at said target temperature. Portable device In order to detect the presence of ice nucleuses in the sample or samples to be analyzed, the portable device 1 according to the invention comprises a refrigeration unit 2 (illustrated in FIGS. 1 to 3) which comprises: a chamber 3 (FIG. ), thermally insulated and in which the sample or samples E are intended to be introduced, - means 4 for the refrigeration of this chamber 3, - means 5 for measuring the temperature within the chamber 3 (Figure 1) control means 6 (FIGS. 1 and 2), in particular for setting a target temperature within the chamber 3, means 7 (FIGS. 1 and 2) for the autonomous power supply of this unit In practice, the refrigeration unit 2 according to the invention is advantageously able to reach a target temperature, negative and close to 0 ° C, which is adapted to the detection of the preserce of ice nucleuses in thesamples reported in room 3.

Chamber The chamber 3 is here delimited laterally by a thermal insulating block 31 comprising a through-hole 32 which is closed at its two ends: on an upper side, by a closure element 33, attached, forming a removable cover, and - On a lower side, by the cooling means 4. The thermal insulation block 31 is for example made of the following material: polyvinyl chloride (or PVC).

This insulating block 31 has the general shape of a frame, comprising (FIG. 2): an inner surface 311 delimiting the through-light 32, an opposite outer surface 312, an upper surface 313 delimiting an upper opening of the through-light 32 and intended to receive the removable cover 33, and - a lower surface 314, delimiting a lower opening of the through-light 32 and intended to rest on the cooling means 4. The through-light 32 advantageously comprises two successive parts: - A lower part 321, at which are provided locations each adapted to receive one of the samples E to be analyzed, and - an upper portion 322, here intended to remain free.

The lower part 321 comprises two superimposed portions, each of parallelepipedal shape, namely an upper portion 3211 and a lower portion 3212 (Figure 2). The upper portion 3211 has a horizontal section which is smaller than the horizontal section of the lower portion 3212.

The removable cover 33 is advantageously also thermal insulator, and preferably transparent, made for example in the following material: polymethylmethacrylate. Moreover, this chamber 3 is here devoid of any means for mixing the air within said chamber 3 (for example a fan). The locations The chamber 3 contains at least two locations 8, provided here within a heat conducting member 9 forming a rack, which are each adapted to receive one of the samples E to be analyzed.

The locations 8 are at least 2 in number, advantageously between 10 and 20, for example 16 in number (FIG. 3). Each location 8 has dimensions that are adapted, to the game, to receive a container containing a sample E to be analyzed, for example a microtube M (Figures 1 and 2).

By "microtube" is meant in particular a small tube with a cap to screw or clip. Such a microtube is conventionally made of plastic, for example polypropylene, capable of withstanding high temperatures and low temperatures. The microtube M advantageously has a capacity of 0.5 ml or 0.2 ml. The locations 8 thus each have a cylindrical upper portion 81 which is extended by a conical bottom portion 82 (FIG. 2). These locations 8 here consist of blind holes, opening at an upper surface of the thermal conductive member 9. The thermal conductive member 9, here monobloc, advantageously provides a direct and complete contact of the walls of the microtube M with the surface of the complementary location 8.

This conductive member 9 is adapted to refrigeration of the surface of its locations 8, in particular by thermal conduction. This thermal conductive member 9 is advantageously made of a metal material, preferably machinable, for example aluminum or aluminum alloy.

This thermal conductive member 9 is located in the chamber 3, reported within the lower portion 321 thereof. The thermal conductive member 9, located in the chamber 3, here has a shape corresponding, with the game, to the lower part 321 of the chamber 3. For this, the thermal conductive member 9 here consists of a part comprising two parts superimposed parallelepipedal: - a lower portion 91, forming a base, corresponding to the game near the lower portion 3212 of the chamber 3 and having a lower surface 911 resting on the refrigeration means 4, and - an upper portion 92, corresponding to the game close at the upper portion 3211 of the chamber 3 and in which are formed the locations 8 (which extend here partially in the base 91) opening at an upper surface 921. The lower portion 91 has a horizontal section which is greater to the horizontal section of the upper part 92.

This structural feature aims to ensure a maximum contact area between the thermal conductive member 9 and the refrigeration means 4. The upper portion 32 of the chamber 3, free, is here delimited between, on the one hand, the upper surface 921 of the thermal conductive member 9 and, secondly, the removable cover 33. Refrigeration means The refrigeration means 4 advantageously comprise a Peltier module 41.

Such a Peltier module is based on a phenomenon of thermoelectric cooling, able to transform into electric current into a difference in temperature. Such a Peltier module, which is conventional in itself, consists of a series of semiconductors having properties of the P or N type, suitably electrically connected. In particular, this Peltier module 41 comprises (FIG. 2): a cold face 411, upper, forming a bottom wall of the chamber 3, and a hot face 412, which is lower, outside the chamber 3 and coupled to means of heat dissipation 42, 43. For example, the cold face 411 of the Peltier module 41 is able to reach a negative temperature, close to 0 ° C, that is to say in particular a temperature between -15 ° C and 0 ° C, preferably between -10 ° C and 0 ° C, preferably between -9 ° C b-6 ° C, more preferably between -8 ° C and -7 ° vs.

The cold face 411 of the Peltier module 41 here has a surface greater than the lower surface 911 of the thermal conductive member 9. In this case, this cold face 411 of the Peltier module 41 is here covered by the lower surface 911 of the thermal conductive member 9 and, on its periphery, by the lower surface 314 of the thermal insulating block 31. The thermal conductive member 9 rests on the cold side 411 of the refrigeration means 4 so as to generate an optimal heat transfer to the locations 8.

The heat dissipation means 42, 43 consist, on their sides, of a superposition of two components: a radiator 42, covering the hot face 412 of the Peltier module 41, and a fan 43.

Dimensional characteristics In a nonlimiting manner, the chamber 3 has the following dimensional characteristics: the volume of the chamber 3 is between 100 and 200 cm 3, and the chamber 3 has a bottom surface of between 30 and 50 cm 2; height between 2 to 4 cm. The cold face of the Peltier module 41 extends over an area of between 80 and 90 cm 2.

Means for the autonomous power supply The means 7 for the autonomous power supply of the portable device 1 advantageously consist of an autonomous power source, such as a 12-volt battery.

This battery consists for example of a lithium-ion battery, or lithium-ion battery. Its main advantages are a high mass energy as well as the absence of memory effect. The self-discharge is relatively small compared to other accumulators.

The battery is advantageously rechargeable: - on the sector via a battery charger with transformer, or - in a vehicle closer to the experiment, for example via a 12V socket, or - by photovoltaic panels in the field for autonomy complete, via an inverter. In general, the power supply of the portable device 1 can also be carried out directly: on the mains via a battery charger with transformer, or in a vehicle as close as possible to the experiment, for example via a 12V plug, or - by photovoltaic panels in the field for complete autonomy, via an inverter. Means for measuring the temperature The means 5 for measuring the temperature consist of a temperature probe, for example of the platinum resistance thermometer type (for example of the Pt 100 type). This probe is advantageously arranged to directly measure the temperature of the thermal conductive member 9 in which the slots 8 are formed. Control means The control means 6 advantageously consist of an on-board system, advantageously an autonomous system comprising electronic means and / or or computer means for controlling the operation of the portable device 1, and in particular of its refrigeration unit 2 (and optionally a pre-cooling unit). In this regard, these control means 6 comprise, for example, at least one microcontroller comprising a recording medium on which is recorded a computer program. This computer program comprises program code means for the operation of the device, when said computer program is executed by the control means 6.

The control means 6 comprise means (not shown) for controlling the operation of the refrigeration means 4, in order to reach the desired target temperature within the chamber 3. This target temperature is in practice advantageously negative and close to 0 ° C, that is to say in particular a temperature between -15 ° C and 0 ° C, preferably between -10 ° C and 0 ° C, advantageously between -9 ° C and -6 ° C, still preferably between -8 ° C and -7 ° C. The control means 6 also comprise means for signaling the attainment of said target temperature (not shown), for example in the form of visual signals (light, screen, etc.) and / or auditory (loudspeaker). The control means 6 also comprise timing means (not shown), adapted to shift the activation of the means to signal the attainment of the target temperature by a predetermined time. These delay means are designed to provide a sufficient period of time (for example a few minutes) to be sure of an effective ice taking of samples E containing ice nucleuses.

Pre-cooling unit The portable device 1 according to the invention may also comprise a pre-conditioning unit (not shown), in parallel with the refrigeration unit 2. Such a pre-conditioning unit may be juxtaposed with the refrigeration unit 2 within a thermal insulation envelope, in particular to facilitate the transfer between the two units. The pre-cooling unit is similar to the refrigeration unit 2 described above in connection with FIGS. 1 to 3. This pre-cooling unit differs from the refrigeration unit 2 only in that its chamber is devoid of thermal conductive member 9 forming a rack. This pre-cooling unit thus comprises: - a chamber, without locations, thermally insulated and in which said sample or samples are intended to be introduced, - means for refrigerating said chamber, for example a Peltier module, - means for measuring the temperature within said chamber, - control means for setting a target temperature within said chamber (positive and close to 0 ° C), said target temperature being greater than the target temperature set in the refrigeration unit, - means for the autonomous power supply of said pre-conditioning unit. Preferably, the control means 6 and the power supply means 7 are common to the refrigeration unit 1 and the pre-cooling unit.

Portable Installation The device 1 according to the invention is advantageously intended to be part of a portable installation 10 (Figure 4). This installation 10 advantageously further comprises a unit for storing accessories suitable for the preparation of samples and / or the processing of data acquired by the implementation of the refrigeration unit 2 (not shown). The accessories for the preparation of samples are advantageously chosen from: - a foldable worktop, - a portable precision scale, - sterile microtubes, - sample collection means (pipettes, etc.). The accessories adapted to the processing of the data acquired include, for example: a computer equipped with means for recording and / or analyzing the collected data and telecommunication means for the transfer of data via a telecommunication network (for example the Internet ), - geolocation means (for example of the GPS type), - a portable device of the mobile phone type.

To facilitate its transport, the portable installation 10 comprises a container 101, for example of the cashbox type, in which is reported the portable device 1. This container 101 is advantageously equipped (Figure 4): - means 102 for its movement on the floor, for example of the caster type, and - gripping means 103 to facilitate its maneuvering on the ground, for example of the telescopic handle type.

Implementation of the portable installation First, the user can optionally extract the portable device 1 out of the container 101 of the portable installation 10. The portable device 1 is for example deposited on a foldable work plan present in the portable installation 10.

The user starts the refrigeration means 4, before returning the samples E, so as to obtain a prior cooling of the chamber of the refrigeration unit 2 and the chamber of the pre-cooling unit. In this regard, the control means 6 advantageously provide control of the respective refrigeration means of the refrigeration unit 2 and the pre-cooling unit, so that: the target temperature of the chamber 3 of the refrigeration unit 2 is advantageously between -15 ° C and 0 ° C, and the target temperature of the chamber of the pre-cooling unit is advantageously between 1 ° C and 4 ° C. The cooling rate obtained with the device 1 according to the invention is advantageously between 3 ° C. and 4 ° C. per minute. The device 1 according to the invention also makes it possible to obtain an inside / outside temperature difference of between 30 ° C. and 40 ° C. (for example -7 ° C. in the chamber 3 of the refrigeration unit 2, for 25 at 26 ° C outside). On their side, the sample (s) E are prepared by suspending the potentially present ice-forming nuclei in a medium of interest consisting of a sample liquid initially devoid of such ice-forming nuclei.

The sample liquid, initially free of ice nuclei, is able to remain in a liquid state at the target temperature. This sample liquid consists for example of sterile distilled water or a sterile buffer (solution with phosphate or potassium salts for example). For example, to detect the presence of ice-forming microorganisms, a known mass of a medium of interest is mixed with a known volume of sterile buffers. Aliquots of 200 μl are distributed in the microtubes M.

To detect the presence of innate ice-forming activity in plant or insect tissue, for example, the samples are cut into pieces whose size is adapted to the volume of the microtubes. These pieces are weighed and deposited in the microtubes in which are then reported 200! IL of a sample liquid initially lacking such ice nucleuses. In practice, the sample volume E in each microtube M is adjusted so that its surface extends below the upper surface 921 of the thermal conductive member 9. The samples E are stored in the pre-unit. conditioning (for example for at least 30 minutes), before carrying out the actual step of determining their ice-forming activity. The chamber of this pre-conditioning unit is for example maintained at a temperature between 1 ° C and 4 ° C. This step of preconditioning the samples aims to activate the ice nuclei to facilitate their detection. In particular, in the case of certain ice-forming microorganisms, an ambient temperature of 15 ° C., or less, for about 1 hour, promotes the activation of the proteins responsible for the ice-forming activity. Following this preconditioning step, the presence of ice nucleuses is detected by bringing the microtubes M into the locations 8 of the refrigeration unit 2. The control means 6 control the refrigeration means 4 so that the temperature of the the thermal conductive member 9 (rack) equilibrates with the target temperature, adapted according to the application, for taking ice samples E containing the elements having an ice-forming activity. For example, for the detection of ice nucleuses of biological origin, the target temperature is advantageously between -15 ° C and 0 ° C, preferably between-2 ° C and -8 ° C. The samples E are incubated for a determined time at this target temperature, advantageously about 4 to 6 min. For this purpose, the delay means advantageously shift the activation of the means to signal the attainment of the target temperature by a predetermined time. After this lapse of time, the control means 6 activate the means to signal the achievement of the target temperature. The microtubes M are extracted and observed successively (one by one) by an operator, so as to distinguish whether: the sampling liquid has taken up in ice, corresponding to a sample E containing ice-forming nuclei, or the sampling liquid remains in a liquid state, corresponding to a sample E devoid of ice nuclei. All the results (nature of the sample, geographic coordinates, quantity tested, ice setting temperature) are collected. If necessary, the results and their geolocation can be transmitted in real time, according to the objectives of the analysis.

Advantage of the invention The portable device 1 according to the invention has various non-limiting advantages: - the determination of the risk of frost damage for flower buds in an orchard, - the identification of plants carrying microorganisms with ice-forming activity (plant species and regions, their most suitable crops), - evaluation of the winter survival potential of insect populations in relation to their supercooling capacity (revised field ecology study) ).

The system is designed to be autonomous, transportable and low energy consumption.

Claims (13)

1. A portable device for detecting the presence of elements having a glacogenic activity in at least one sample (E), which portable device (1) comprises a refrigeration unit (2) comprising: a chamber (3), thermally insulated and wherein said sample or samples (E) are intended to be introduced, - means (4) for refrigerating said chamber (3), - means (5) for measuring the temperature within said chamber (3), - means (6) for setting a target temperature within said chamber (3), said target temperature being adapted to the detection of the presence of elements having a gelogenic activity in said one or more samples (E), - means (7) for the autonomous power supply of said refrigeration unit (2), characterized in that said chamber (3) contains at least two locations (8) which are each adapted to receive the one of said samples (E), and in that said refrigeration unit (2) further comprises means (6) for signaling the attainment of said target temperature. 2.- portable device according to claim 1, characterized in that the locations (8) are, on the one hand, formed in a thermal conductive member (9) located in the chamber (3) and, on the other hand, adapted each receiving a container (M) containing one of said samples (E). 3.- portable device according to claim 2, characterized in that the thermal conductive member (9) rests on the refrigeration means (4). 4. A portable device according to any one of claims 1 to 3, characterized in that the locations (8) each have dimensions which are adapted, with the game, to receive a microtube (M). 5.- portable device according to any one of claims 1 to 4, characterized in that the chamber (3) is delimited, in part, by the refrigeration means (4). 6. A portable device according to claim 5, characterized in that the refrigeration means (4) comprise a Peltier module (41) which comprises: a cold face (411) forming at least a part of one of the walls; of the chamber (3), and - a hot face (412) external to said chamber (3) and coupled to heat dissipation means (42, 43). 7.- portable device according to any one of claims 1 to 6, characterized in that the chamber (3) is devoid of means for mixing the air within said chamber (3). 8.- portable device according to any one of claims 1 to 7, characterized in that it further comprises timing means adapted to shift a given time the activation of the means to signal the achievement of the target temperature . 9. A portable device according to any one of claims 1 to 8, characterized in that it comprises a pre-conditioning unit comprising: - a thermally insulated chamber and wherein said one or more samples are intended to be introduced, means for refrigerating said chamber; means for measuring the temperature within said chamber; means for setting a target temperature within said chamber, said target temperature being greater than the temperature; set target in the refrigeration unit, - means for the autonomous power supply of said pre-conditioning unit. 10. Portable installation for detecting the presence of elements having a glacogenic activity in at least one sample, characterized in that it comprises: a portable device (1) according to any one of claims 1 to 9, and a unit for storing accessories adapted to the preparation of the samples and / or adapted to the processing of the data acquired by the implementation of said portable device (1). 11. Portable installation according to claim 10, characterized in that it comprises means (102) for its movement on the ground and gripping means (103) for its maneuver by a user. 12. A method for detecting the presence of elements having a gelogenic activity in at least one sample, by means of a portable device according to any one of claims 1 to 9, characterized in that it consists: - to prepare said sample or samples (E) by suspending elements having a gelogenic activity potentially present in a medium of interest by means of a sampling liquid initially free of such elements having a gelogenic activity; said samples (E) in the locations (8) of the chamber (3) of the refrigeration unit (2) of said portable device (1), - to control the refrigeration means (4) of the refrigeration unit ( 2) of said portable device (1) so as to reach the target temperature suitable for taking in ice samples (E) containing the elements having a gelogenic activity, and - once said target temperature reaches to determine, on the one hand, the sample or samples (E) whose sample liquid has taken on ice, corresponding to the sample (s) containing elements having a gelogenic activity and, on the other hand, the sample or samples (E) whose sample liquid remains in a liquid state, corresponding to the sample (s) lacking elements having a gelogenic activity. 13.- Method according to claim 12, for the detection of elements having a biogenic activity of biological origin, characterized in that the target temperature is between -15 ° C and 0 ° C, preferably between -9 ° C and -6 ° C.