Abstract
A device for determining contamination of a fluid by microorganisms has a housing with an internal volume, a cover closing the housing, a fluid inlet port, at least one filtration member, at least one nutrient layer including a composition of a microbiological culture medium, characterized in that the device includes a fluid outlet port, and in that the cover has an inner surface in the internal volume extending radially about the fluid inlet port up to a peripheral edge of the cover, said inner surface being inclined and converging towards the fluid inlet port, and in that the bottom of the housing has a surface extending radially about the fluid outlet port up to the side wall of the housing, said inner surface being inclined and converging towards the fluid outlet port.
Claims
1. A device for determining contamination of a fluid by a microorganism, said device comprising: a housing having an internal volume delimited by at least one side wall and a bottom, a cover closing the housing and positioned opposite the bottom, a fluid inlet port arranged on the cover that opens out into the internal volume of said housing, the fluid inlet port extending along an axis that is substantially secant to the cover, at least one filtration member arranged in the internal volume, at least one nutrient layer comprising a microbiological culture medium, wherein the device includes: a fluid outlet port arranged on the housing that opens out into the internal volume of said housing, and in that the cover has an inner surface in the internal volume extending radially about the fluid inlet port up to the peripheral edge of the cover, said inner surface being inclined or curved and converging towards the fluid inlet port, a support grille configured to support the nutrient layer and in that the bottom of the housing has a surface extending radially about the fluid outlet port up to the side wall of the housing, said surface being inclined and converging towards the fluid outlet port.
2. The device as claimed in claim 1, in which the inclination of the inner surface of the cover is strictly greater than 4°.
3. The device as claimed in claim 1, in which the inclination of the surface of the bottom is strictly less than 0°.
4. The device as claimed in claim 1, in which the fluid inlet port projects into the internal volume of the housing relative to the inner surface of the cover.
5. The device as claimed in claim 1, in which the filtration member is arranged in the housing at a given distance h from the inlet port, the given distance h being strictly greater than 1 mm.
6. The device as claimed in claim 1, in which the housing has a first circumferential bearing surface shaped to cooperate complementarily with an edge of the cover.
7. The device as claimed in claim 1, in which the housing has at least one second bearing surface extending in the internal volume and shaped to receive a peripheral portion of the filtration member, said second bearing surface being shaped to cooperate with a portion of the cover such that the peripheral portion of the filtration member is clamped between the cover and the housing.
8. The device as claimed in claim 1, in which the bottom of the housing has supporting ribs arranged radially relative to the fluid outlet port, said ribs being designed to hold the support grille and to guide the fluid towards the fluid outlet port.
9. An assembly comprising at least one fluid feed and at least one device as claimed in claim 1, said device being connected by means of the fluid inlet port thereof to a fluid feed.
Description
SHORT DESCRIPTION OF THE FIGURES
[0096] The invention can be better understood from the description below of an embodiment of the present invention, given as a non-limiting example and explained with reference to the attached schematic figures. The attached schematic figures are listed below:
[0097] FIG. 1 is a perspective view of the device for determining contamination according to the invention,
[0098] FIG. 2 is a median cross-section view of the device shown in FIG. 1,
[0099] FIG. 3 is a detailed view of FIG. 2,
[0100] FIG. 4 is a partial perspective view of the device according to the invention showing the support grille seated in the housing,
[0101] FIG. 5 is a perspective bottom view of the cover of the device according to the invention,
[0102] FIG. 6 is a perspective view of the inside of the housing of the device according to the invention,
[0103] FIG. 7 is a cross-section view of the cover and of the filtration member of the device according to the invention, and
[0104] FIG. 8 is a cross-section view of the housing of the device according to the invention.
[0105] FIG. 9 is a schematic view of a first step of a first usage mode of the device according to the invention,
[0106] FIG. 10 is a schematic view of a second step of the first usage mode of the device according to the invention,
[0107] FIG. 11 is a schematic view of a third step of the first usage mode of the device according to the invention,
[0108] FIG. 12 is a schematic view of a first step of a second usage mode of the device according to the invention,
[0109] FIG. 13 is a schematic view of a second step of the second usage mode of the device according to the invention,
[0110] FIG. 14 is a schematic view of a third step of the second usage mode of the device according to the invention.
DETAILED DESCRIPTION OF THE FIGURES
[0111] The device 1 for determining contamination of a fluid by microorganisms according to the invention includes a housing 2, a cover 3, a filtration member 4, a nutrient layer 5, and a grille 6, as shown notably in FIG. 2.
[0112] As shown in FIG. 1, only the cover 3 and the housing 2 are visible from the outside. Advantageously, the cover 3 and the housing 2 are sealed together by ultrasound. According to the cross-section shown in FIG. 2, the filtration member 4 is arranged in the internal volume of the housing 2, the nutrient layer 5 is arranged beneath the filtration member 3, preferably in contact with this latter and a support grille 6 is arranged between the nutrient layer 5 and the bottom 22 of the housing 2.
[0113] According to the invention, the filtration membrane 4 is permeable to fluids and in particular to a gas or to a liquid having a viscosity that enables microbiological filtration free of all solid particles.
[0114] The device 1 also includes a fluid inlet port 11 and a fluid outlet port 12, as shown in FIG. 1. The fluid inlet port 11 is positioned on the cover 3 and the fluid outlet port 12 is positioned on the housing 2 and preferably on the bottom of the housing 2. The fluid inlet port 11 and the fluid outlet port 12 open out into the internal volume of the housing 2, as shown in FIG. 2. When the inlet port and the fluid outlet port are blocked by the stoppers, the device according to the invention is fluid tight.
[0115] As shown in FIG. 2 for example, the fluid inlet port 11 projects into the internal volume of the housing 2 relative to the inner surface 31 of the cover 3. Preferably, the fluid inlet port 11 is arranged substantially in the center of the cover 3. The fluid inlet port has a first end 11a extending outside the cover 3 that is designed to cooperate with a stopper (not shown) and a second end 11b extending inside the internal volume, the second end being provided with at least one lateral orifice 11c opening out into the internal volume and oriented to at least partially spray the fluid towards the inner surface 31 of the cover 3.
[0116] As shown for example in FIG. 2, the fluid outlet port 12 has a first end 12a extending outside the housing 2 that is designed to cooperate with a stopper and a second end 12b that is flush with the bottom 22 of the housing 2.
[0117] The fluid inlet port 11 and the fluid outlet port 12 extend respectively along an axis substantially secant and preferably perpendicular to the cover 3 or to the bottom of the housing 2. In the example shown in FIG. 2, the fluid inlet port 11 and the fluid outlet port 12 are aligned and arranged opposite one another.
[0118] The housing 2 of the device 1 is described below in greater detail with reference to FIGS. 1, 2, 6 and 8. As shown in FIG. 1, the housing 2 is substantially cylindrical.
[0119] As shown in FIG. 2, the housing 2 has an internal volume delimited by at least one side wall 21 and a bottom 22.
[0120] FIGS. 2 and 8 show a cross section of the housing 2, which shows a first circumferential bearing surface 23 shaped to cooperate complementarily with an edge 33 of the cover 3. Furthermore, according to the invention, the housing 2 has at least one second bearing surface 24 extending in the internal volume and shaped to receive a peripheral portion 41 of the filtration member 4, said second bearing surface 24 being shaped to cooperate with a portion 34 of the cover 3 such that the peripheral portion 41 of the filtration member 4 is clamped between the cover 3 and the housing 2, as shown in detail in FIG. 3. Furthermore, the housing 2 has a third bearing surface 25 that is designed to receive the support grille 6 and more specifically to receive a peripheral edge 65 of the support grille 6. The third bearing surface 25 extends inside the internal volume of the housing 2 and is an external shoulder 26 of the housing 2, as shown in FIG. 8.
[0121] As shown in FIG. 8, each bearing surface 23, 24, 25 has a different diameter and advantageously the first bearing portion 23 has a diameter that is greater than the second bearing portion 24, which in turn has a diameter that is greater than the third bearing portion 25.
[0122] As clearly shown in FIG. 6, the bottom 22 of the housing 2 has a plurality of supporting ribs 27 designed to support the support grille 6 and to guide the fluid towards the fluid outlet port 12. The supporting ribs 27 are arranged radially relative to the fluid outlet port 12. The supporting ribs 27 project from the surface of the bottom 22 and extend substantially perpendicularly to said surface of the bottom 22, as shown in the cross section in FIG. 8.
[0123] As shown notably in FIG. 8, the bottom 22 of the housing 2 has a surface 28 extending radially about the fluid outlet port 12 up to the side wall 21 of the housing 2, said inner surface 28 being inclined and converging towards the fluid outlet port 12 to facilitate drainage of the fluid. In the example shown in FIGS. 2 and 8, the inclination β of the surface 28 of the bottom 22 is strictly less than 0° and is between −5° and −10°. The applicant has carried out tests demonstrating that if the bottom is flat, the fluid drains only partially or not at all.
[0124] The cover 3 of the device 1 is described below in greater detail with reference to FIGS. 1, 2, 5 and 7.
[0125] As shown in FIG. 1, the cover 3 has a substantially cylindrical base surmounted by the fluid inlet port 11. The cover 3 has an inner surface 31 closing the internal volume of the housing 2. The inner surface of the cover 3 extends radially about the fluid inlet port 11 up to a peripheral edge 32 of the cover 3, said inner surface 31 being inclined and converging towards the fluid inlet port 11. The inner surface 31 therefore has an overall frustoconical shape extending from the fluid inlet port 11 and widening up to the peripheral edge 32 of the cover 3. In a variant that is not shown, the inner surface can be curved.
[0126] In the example shown in FIGS. 2 and 7, the inclination α of the inner surface 31 of the cover 3 is strictly greater than +4° and is between +5° and +15°. The applicant has carried out tests demonstrating that if the inner surface of the cover has an inclination equal to or less than 4°, the fluid is not uniformly distributed over the filtration member 4.
[0127] As shown in FIG. 7, the filtration member 4 is arranged in the housing 2 at a given distance h from the fluid inlet port 11. Advantageously, the given distance h is strictly greater than 1 mm, and preferably between 1.5 mm and 5 mm. Indeed, tests carried out by the applicant have demonstrated that the filtration member 4 has to be at a given distance h to enable the microorganisms to grow when the device 1 according to the invention is incubated. This given distance h is dependent on a minimum volume of air required to grow said microorganisms. In the example shown in FIGS. 1, 2, 5 and 7, the cover 3 is transparent or translucent, which enables growth of the microorganisms to be observed.
[0128] According to a feature of the invention, the support grille is designed to support the nutrient layer and the filtration member.
[0129] The support grille 6 of the device 1 is described below in greater detail with reference to FIGS. 2 and 4.
[0130] As shown in FIG. 2, the support grille 6 is arranged between the nutrient layer 5 and the bottom 22 of the housing 2. The support grille 6 has an overall cylindrical shape and is the same size as the nutrient layer 5.
[0131] As shown in FIG. 4, the support grille 6 has a plurality of through holes 61 distributed over the entire grille 6, which helps to distribute the fluid that has passed through the nutrient layer 5 over the entire surface 28 of the bottom 22 in order to drain said fluid as quickly as possible.
[0132] As shown in FIG. 2, the support grille 6 rests on the supporting ribs 27 of the housing 2. The support grille 6 has a peripheral edge 65 resting on the third bearing surface 25 of the housing 2, as shown in FIGS. 2 and 3.
[0133] In a variant that is not shown, the grille only rests on the third bearing surface 25 of the housing, and the supporting ribs are optional.
[0134] Two possible uses of the device according to the invention are described below with reference to FIGS. 9 to 14.
[0135] According to a first use illustrated in FIGS. 9 to 11, a syringe 100 or any other element including a piston containing the fluid to be analyzed is connected to the fluid inlet port 11 of the device 1, and a collector 101 or another syringe is connected to the fluid outlet port 12 of the device 1, as shown in FIG. 9. A three-way valve 102 is positioned between the device 1 and the syringe 100, the syringe 100 being connected indirectly to the fluid inlet port 11 of the device 1. Initially and as shown in FIG. 9, the first inlet 102a of the valve 102 is connected to the syringe 100 and closed, the second inlet 102b is open and connected to an air intake, and the outlet 102c is also open and connected to the fluid inlet port 11 of the device. This enables a vacuum to be created before the device is used and before the fluid to be analyzed/filtered is introduced.
[0136] Subsequently and as shown in FIG. 10, the first inlet 102a of the valve 102 is inserted and the fluid is injected into the device 1, the piston of the syringe 100 enabling the fluid to be pushed into the device 1, the second inlet 102b of the valve is then closed and the outlet 102c is open to enable the fluid to flow through the device 1.
[0137] Once all of the fluid to be analyzed has been injected through the device 1, the fluid is recovered in the collector 101, as shown in FIG. 11.
[0138] According to a second use illustrated in FIGS. 12 to 14, a tank 103 containing the fluid to be analyzed is connected to the fluid inlet port 11 of the device 1, and a syringe 104 or any other element including a piston and enabling aspiration of the fluid is connected to the fluid outlet port 12 of the device 1, as shown in FIG. 12. A three-way valve 105 is positioned between the device 1 and the syringe 100, the syringe 100 being connected indirectly to the fluid inlet port 11 of the device 1. Initially and as shown in FIG. 12, the first inlet 105a of the valve 102 is connected to the collector 103 and closed, the second inlet 105b is open and connected to an air intake, and the outlet 105c is also open and connected to the fluid inlet port 11 of the device 1.
[0139] Subsequently and as shown in FIG. 13, the first inlet 105a of the valve 105 is opened and the fluid contained in the collector 103 is aspirated by the syringe 104 positioned downstream of the device 1, the second inlet 105b of the valve is then closed and the outlet 105c is open to enable the fluid to flow through the device 1.
[0140] Once all of the fluid to be analyzed has been aspirated through the device 1, the fluid is recovered in the syringe 104, as shown in FIG. 14. Naturally, the capacity of the syringes and tanks or collectors is suitable for the volume of fluid to be analyzed.
[0141] Regardless of the use of the device described above, once the fluid has been injected (FIGS. 11 and 14), it is advantageous to inject sterile air via the air intake 110 to eliminate any stagnant water from the surface of the filtration member 4 of the device 1.
[0142] Indeed, the presence of fluid, even in small quantities, on the surface of the filtration member could result in the spread of bacterial colonies, false negatives or difficulties counting colonies after the incubation step. For this purpose, sterile air is aspirated by the syringe 100 or the tank 103 through the valve 102, 105, then injected into the device 1, in order to dry the surface of the filtration member 4.
[0143] The advantages of these uses are that these usage techniques are simple, they require no effort (notably the first use), the workflow lasts less than one minute in total, no laboratory infrastructure is required to carry out these operations, no staff qualified in microbiology are required, and the operation is very reproducible.
[0144] Naturally, the invention is not limited to the embodiments described and/or illustrated in the attached figures. Modifications may be made to the invention, notably in terms of the constitution of the different elements or by substitution for technical equivalents, without thereby moving outside the scope of protection of the invention.
