ES2266005T3 - DEVICES FOR MICROBIOLOGICAL EXAMINATION OF A SAMPLE OF LIQUID UNDER PRESSURE AND METHOD TO EVACUATE THIS DEVICE. - Google Patents

Abstract

Device for microbiological examination of a sample of liquid under pressure, which has an intake body, a filtration membrane and an evacuation body, said admission body having a reservoir, in a wall of which a liquid inlet opening is made , said membrane closing said reservoir, said evacuation body having means for supporting said membrane on the opposite side with respect to said reservoir and a liquid outlet opening, said intake body and said evacuation body integrally molded locking means , characterized in that said membrane (4) is annularly held at the periphery between a first member (9) that is part of said intake body (2) and a second member (32) that is part of said evacuation body (3) , one of said first member and said second member having an elastomer seal (13) by means of which it contacts said membrane frog (4), and because said locking means (7, 31) are adapted to allow the opening of said device requiring only a separation movement between said first member (9) and said second member (32), said means having blocking axial engagement means (7, 31) between the intake body (2) and the evacuation body (3), with one of the intake body (2) and the evacuation body (3) having at least one engagement pin axially oriented (7), while the other has means (42, 44, 45) to receive said hitch pin (7), and because the hitch pin (7) extends protruding from the edge of a skirt (6) which is part of one of said intake body (2) and said evacuation body (3) that includes it.

Description

Device for microbiological examination of a liquid sample under pressure and method to evacuate this device.

The invention relates to devices for Microbiological examination of a sample of fluid under pressure.

Said device is already known through the French patent 2 677 664, which has an intake body, a filtration membrane and an evacuation body. The body of admission has a deposit, in a wall of which it is practiced a liquid inlet opening, closing the east membrane tank when welded on the edge of the side wall of this tank, the evacuation body being designed to support the membrane on the opposite side with respect to the reservoir and being provided with a liquid outlet opening, blocking with each other the intake body and the evacuation body through the screwing under the molded thread elements of full way.

Taking a sample to be examined It is done by connecting the inlet opening of the tank admission body to a source of liquid under pressure, so that the tank is filled with this liquid that can leave it only through the filtering membrane, being coated this liquid from the other side of the membrane by the body of evacuation and being emptied from it through the opening output

In order to prevent the liquid that has passed to through the exhaust membrane from the evacuation body by somewhere other than through the exit opening, the body of admission has, around the membrane, a flange provided of a lip that rests on the evacuation body to obtain the required shutter.

This makes possible to an important degree, by example, the collection of the liquid emptied through the opening of exit of a graduated container, to know exactly the volume of the liquid sample that has passed through the membrane.

EP 059 809 A describes a unit of disposable filtering for similar purposes, but in which the sample of liquid is not under pressure. This device understands how intake body an open end shell and as a body of evacuation a cup-shaped receptacle, a support plate in funnel shape for the filtering membrane and a support plate arranged on the support plate that is supported by a internal shoulder of the receptacle to which it can be fixed so permanent by suitable cement or by welding Ultrasonic The bottom end of the envelope has a portion narrowed so that it can be received on a flange of the receptacle, the axial length of the narrowed portion being such and its position inside the flange that there is some axial distance between the top of the receptacle flange and an edge of the narrowed portion. Enteriza is formed a plurality of full vertical nerves with the envelope. These nerves have enough length to save this axial distance and can be fixed to the upper end of the receptacle flange by Ultrasonic welding to join the wrap to the receptacle. Because that the fixation of the nerves to the receptacle occurs only at intervals spaced around the periphery of the receptacle, the nerves provide weak points of "detachment" to facilitate the removal of the envelope from the receptacle. In one embodiment, an annular gasket flat is arranged between the lower end face of the shell and the support plate, the internal periphery of this packing between an inner foot of the shell and the membrane filtering, while the outer periphery of the gasket It is compressed by an outer foot of the shell and rests on the flange of the support plate, thus providing this packing, on the other hand, a liquid tight seal between the shell and the filtering membrane and, on the other hand, a air tight gasket between the shell and the support plate. In other embodiments, the support plate comprises a tongue erect that is received between the inner foot and the outer foot of the wrapped, while the flat ring gasket is replaced by a gasket that has been placed in one place between the flange and the tongue of the receptacle.

US 4 678 576 A describes a device for similar purposes, but not for a low liquid Pressure. The described device comprises, as a body of admission, an open-ended upper body and as a body of evacuation, a cup-shaped receptacle and a support plate, also provided a locking flange to block the intake body and evacuation body. The support plate is sandwiched between a top collar portion of a collar included in the receptacle and an internal shoulder of a narrowed portion that includes the upper body, being engaged respectively the ring, by its internal thread, with the thread outer of the lower portion of the receptacle collar and, by an upper flange, with the lower outer shoulder of a tab cleft included in the upper body. In one embodiment, it they have two O-rings respectively on either side of the support plate, while in another embodiment it is arranged single H packing.

US 4 319 996 describes a filter device comprising a housing and a membrane porous The housing is made in the form of a molded part upper and a lower molded part that are coupled and joined tightly with the round periphery of the membrane between them. The membrane divides the housing into a lower inlet chamber and an upper exit chamber. The input camera has a liquid inlet opening for access of the liquid to be be filtered, and the exit chamber has a wall with a liquid outlet opening for the filtered liquid.

US 5 688 460 describes a method to manufacture hermetically sealed filter units. A filter element is aligned between two housing parts and a thermoplastic skirt. After tightening the parts of housing each other, a band of injection molded overmold of thermoplastic material around the portions external parts of the housing to form a joint tight on the edge of the filter element.

EP 0 319 701 A describes an apparatus for filtering particularly suitable for hydraulic systems of drive and control. This device has a thin filter layer between permeable support surfaces and provides a sharp flow resistance

It should be noted that, once closed Hermetically, the units according to US 4 319 996, US 5 688 460 and EP 0 319 701 A are not intended to be open to retrieve the filter element.

The invention relates to a device of the same class known through French patent 2 677 664, but simpler, more comfortable and cheaper, both to manufacture How to use

To that end a device is proposed for microbiological examination of a sample of fluid under pressure, which it has an intake body, a filtering membrane and a body of evacuation, said admission body having a deposit, in a wall of which a liquid inlet opening is made, said membrane closing said reservoir, said body having evacuation means to support said membrane on the opposite side with respect to said reservoir and a liquid outlet opening, having said molded body integrally and said evacuation body means of mutual blocking; characterized because said membrane is held annularly at the periphery between a first member that is part of said admission body and a second member that is part of said evacuation body, having one of said first member and of said second member a sealing gasket of elastomer through which they enter contact with said membrane, and because said blocking means are adapted to allow the opening of said device requiring only a separation movement between said first member and said second member, having said blocking means axial engagement means between the intake body and the body of evacuation, having one of the intake body and the body of evacuation at least one axially oriented hitch pin while the other has means to receive said pin of hitch, and because the hitch pin extends overhanging from the edge of a skirt that is part of the one of said body of admission and said evacuation body that includes it.

Therefore, unlike the device previously mentioned known through French patent 2 677 664, in which the blocking means are constituted by thread elements, the opening of the device according to the invention is realized with a movement without rotation between the intake body and evacuation body.

Therefore, the device according to the invention makes it possible to eliminate any risk of folding the membrane at the time of opening the device when it find then in a wet state.

In addition, the elastomer sealing gasket, although it is only present on one of the faces of the membrane, it makes it possible to obtain sealing on both sides of the membrane, it is say, both with the first member and with the second, from the simple fact that said members hold the membrane, that is, they are kept close to each other, so that it is not necessary, to close the device according to the invention, perform a rotation movement, unlike the device previously mentioned known through French patent 2 677 664 which requires, so that the sealing lip in the body of admission is applied with the required intensity on the body of evacuation, so that the assembly is carried out by screwed with a considerable torque.

Therefore, the device according to the invention is much simpler and more convenient to use than the previously mentioned device known through the French patent 2 677 664, and it is also easier to manufacture, since, on the one hand, it is not necessary to make forecasts for get the seal between the membrane and the intake body by welding and, on the other, the sealing around the membrane between the intake body and the evacuation body, since, in the device according to the invention, the fastening of the membrane between the first member and the second member makes possible Get these two cases of shutter directly.

Thanks to the fact that the blocking means they have means for axial engagement between the intake body and the evacuation body, mounting the device according to the invention is particularly simple, since it is enough to gather the intake body and the evacuation body to block them by hook.

It should be noted that the gasket of elastomer, because of its elasticity, recovers the slack necessary to allow hitching, so that once mounted, the intake body and the evacuation body are maintained without axial clearance relative to each other.

The fact that one of the admission body and the evacuation body have at least one hitch pin axially oriented, while the other has means to receive said hitch pin, is preferable for reasons of simplicity and comfort, both in manufacturing and in use.

Preferably, the membrane is maintained solely because it is subject annularly in the periphery between said first member and said second member.

The manufacture and use of the device according to the invention they are thus particularly simple, since no operation such as the shutter of the existing membrane in the previous device, while, after opening the device according to the invention, the membrane, which is not fixed to either the first member or the second member, can be recovered directly, for example, with tweezers sterile in order to introduce a culture into a Petri dish conventional.

Preferably again, said pin of hitch is connected to the rest of that one of said body of admission and said evacuation body that includes it, by A removable zone.

The release of the blocking means between the hitch body and evacuation body can be performed thus by simple breakage of the hitch pin or even of a plurality of hitch pins if the device according to The invention has more than one.

According to other preferred features, said evacuation body has a circular plateau provided in its media center to support said membrane and which has, around of said support means, a wall comprising a surface which looks towards said elastomer sealing gasket, which is part of said intake body, said membrane being pressed between said surface and said seal.

This arrangement actually offers the advantage. of being relatively simple to execute and to obtain results excellent in terms of shutter.

According to other preferred features, and for the same reasons, said outlet opening of the body of evacuation is in the continuation of the internal passage of a tube of Coaxially arranged output.

Preferably, said evacuation body it has, around said outlet tube, an annular nerve that narrow towards its end.

This nerve makes it possible in particular to evacuate the device according to the invention placing it directly in a vacuum flask with said outlet tube applied in the central opening of the cap of said bottle and said annular nerve supported on this plug.

The invention also relates, in a second aspect, to a method of evacuating the device in this way according to the invention.

The explanation of the invention will continue now with the description of an illustrative embodiment, given to continued as a non-limiting illustration, with reference to the accompanying drawings, in which:

Figure 1 is an elevation view of a device according to the invention;

Figure 2 is an elevational view in section of this device;

Figures 3 and 4 are similar views but that show, respectively, only the intake body and the body evacuation;

Figure 5 is an enlargement of the part of the Figure 2 located in the lower right part;

Figure 6 is an elevation view in section partial seal of the seal with which the body of admission;

Figure 7 is an elevation view in section which shows how the device is used according to the invention to sample the liquid to be examined;

Figure 8 is a similar view showing the way in which the device according to the invention is evacuated, after a sample has been taken, by means of a syringe;

Figure 9 is the corresponding view from above, showing a possible second place for the syringe with a partially illustrated syringe;

Figure 10 is a view similar to Figure 8, in which the evacuation is carried out with a vacuum flask;

Figures 11 and 12 are elevational views in section that show how the hitch pins are break and separate from the intake body to free the last of the evacuation body;

Figure 13 shows how the membrane is recovered with tweezers after this release;

Figure 14 shows the way in which the membrane is deposited in a Petri dish.

The device 1 for microbiological examination of a sample of liquid under pressure shown in the drawings, and mainly in figures 1 and 2, it has in general terms a Revolution symmetry around a central axis. Has a body of intake 2, an evacuation body 3 and a filtration membrane Four.

The intake body 2 has a reservoir 5, a skirt 6 that is connected externally to tank 5 and four hitch pins 7 extending protruding from the skirt 6, in axial direction.

The tank 5 has an extreme wall 8 and a
side wall 9.

Two diametrically opposite tubes 10 are extend protruding outward from the side wall 9, by on top of skirt 6, each of these tubes constituting a Female Luer connector adapted to internally receive a male Luer connector, as will be explained below with the help of Figure 7, continuing the internal passage of each tube 10 through a opening 11 made in the wall 9, this opening being in the immediate proximity of the extreme wall 8.

The side wall 9 ends at the opposite end to the extreme wall 8 on an edge that is part of a joint shutter 13, a groove 14 being made for that effect in the rigid part of the wall 9, as will be explained in more detail subsequently with the help of figures 2, 3 and 6.

The skirt 6 is connected to the tank 5 by the outside the side wall 9, at a level between the groove 14 and the tubes 10, the skirt 6 having a conical wall 15 and a cylindrical wall 16, the skirt 6 being connected to the wall 9 by the small diameter end of the wall 15 while the connection between walls 15 and 16 takes place at the end of large diameter of the wall 15, the connection between walls 15 and 16 approximately at the level of the edge of the wall 9.

Each of the hitch pins 7 has a general profile in the form of a symmetric trapezoid with respect to the axial direction, the side forming the free end 18 of the pin 7 which is parallel to that by which this pin is connected to the skirt 6, and more precisely to the edge of the wall 16, narrowing pin 17 constantly between its connection to skirt 6 and its free end.

On each side of each pin 7, a notch 17 on wall 16, some distance from the edge of the same.

Each pin 7 has, from its free end 18, an internal surface 19 that is straight, that is, parallel to the axial direction, to a dihedral 20 from which surface 19 it is tilted inwards and towards the wall 16.

As for the external surface 21 of each pin 16, leans out and to the wall 16, surface 21 extending between surface 18 and a transversely oriented surface 22 that connects the surface 21 and a slot 23 located between an external shoulder 24, whose surface 22 constitutes the edge and a displaced surface 25 inward with respect to surface 21, the surface being 25 the continuation of the external surface of the wall 16.

It should be noted that the portion of each pin 7 located between the bottom of the groove 23 and the wall edge 16 has a thickness that is minimum at the level of the dihedral 20.

Therefore, it is in the dihedral region 20 where pin 7 breaks if sufficient pressure is exerted  large on surface 21, and more generally if exercised there on the pin 7 a radial force directed inwards, the force necessary to break the pin 7 being smaller the more near the extreme surface 18 apply.

As seen more particularly in Figure 1, surface 21 has edges parallel to the axial direction, each pin 7 having a notch 26 with an L-shaped profile between the side edges of the surface 21 and the edges side of the pin 7.

As best seen in Figure 4, the body of evacuation 3 has a circular plateau 30 and a skirt 31 arranged on a step around plateau 30.

The latter has an annular transverse wall 32 bounded on the opposite side of the skirt 31 by a surface 33 which is flat for the most part but that has a slight bevel towards the outside.

The inner periphery of the wall 32 is connected to a delimited wall 34, on the surface side 33, for a surface 35 that is concave for the most part, displaced with respect to surface 32 in the axial direction, towards the skirt 31, the perimeter of the surface being connected 35 and the inner periphery of the surface 33 by a surface slightly conical 36.

The wall 34 is connected in the center to a tube 37, whose internal passage extends into the wall 34 through an outlet opening 38, evacuation channels concentric 39 that are inserted into wall 34 from the surface 35, radially oriented channels (not visible in the drawings) which are also made with the same depth as the channels 39, naturally opening these radial channels within the outlet opening 38, through which, therefore, all the liquid evacuated through the channels made in the wall 34 hollowed out with respect to surface 35.

At the junction between walls 32 and 34 is located an annular nerve 40 protruding from the walls  32 and 34 on the side of skirt 31, this nerve narrowing towards its free end in a V profile, so that this end It constitutes an edge.

The plateau 30 also has a side wall tubular 41 which is connected at one end to the wall 32, while  which, on the other end, is connected to skirt 31.

The last one has an annular wall oriented transversely 42 and an axially oriented cylindrical wall 43, the wall 42 being connected by one of its ends to the wall 41 and on the other to the wall 43.

On wall 42, in proximity to the wall 41, four openings 44 are made, which have between them the same angular spacing as between hitch pins 7, is that is, they are spaced at 90º, these openings having a profile corresponding to the larger profile of the pins 7, so that the the latter can each pass through a respective opening 44.

Each opening 44 is limited on the side external by an axially oriented tooth 45 protruding in the opposite side from plateau 30.

Each tooth 45 extends protruding in one height corresponding to the depth of the groove 23 and has a thickness less than the width of the groove 23, the distance being separate each tooth 45 from the wall 43 greater than the thickness of shoulder 24 (see figure 5).

At the level of each opening 44, the wall 43 has a notch 46 of general rectangular shape with rounded corners,  which extends for about two thirds of the height of the wall 43 and over a width that is approximately twice the hook pin width 7.

Wall 43 also has four notches 47, each of them arranged halfway between two notches successive 46, the notches 47 having a rounded shape whose maximum height corresponds to approximately one third of the height of the wall 43.

The evacuation body 3 also comprises a porous plate 48 (not shown in Figure 4), which has a constant thickness with two opposite surfaces in the same way as surface 35, its diameter and thickness being the same as those of the surface 36.

When the filter body 2 is mounted, the evacuation body 3 and membrane 4, as shown mainly in figures 1 and 2, the membrane 4 is held between the edge of the side wall 9 of the reservoir 5 of the body of intake 2 and surface 33 of wall 32 of the circular plateau 30 of the evacuation body 3, the bodies 2 and 3 under hook pins 7 and skirt 31 that are mutually willing as you can see more particular in figure 5.

It should be noted that tooth 45 of the wall 42 fits into slot 23 of pin 7 and that shoulder 24 of this pin fits into the space between wall 43 and the tooth 45, so that the cooperation between shoulder 24 and the tooth 45 provides a very powerful blockage of pin 7 in the skirt 31, able to withstand relatively large forces that tend to move bodies 2 and 3 in the sense of separating one from other.

It should also be noted that end 18 of the pin 7 is lowered with respect to the free end of the wall 43, so that when device 1 is placed in a surface with the evacuation body 3 at the bottom, the device 1 rests on this surface by means of skirt 31, not exerting for this reason any force on the pins 7 which, therefore, are not at risk of being broken by accident.

As can be seen in Figure 2, when the device 1 is mounted, gasket 13, and more particularly its cushion, it is very compressed compared to the unloaded form of this gasket shown in the figure 6.

As indicated above, this meeting shutter has a general T-shaped profile, whose branch longitudinal forms a nerve 50 designed to be inserted into the slot 14 and whose transverse branch forms a cushion 51 designed to come into contact with the membrane 4.

The free end of the cushion 51 has a central groove 52 that makes it possible to release both lips annular 53 allowing the best cooperation of the cushion 51 with the membrane 4.

It should be noted that the union between the nerve 50 and the cushion 51 is made by a straight surface in the inner side, while on the outer side there is a bevel 54.

This bezel corresponds in fact with a lip chamfered 55 on the outer periphery of the end of the part rigid wall 9, making this chamfered lip possible laterally contain the cushion 51 on the outer side so that move mainly inwards, that is, towards the camera delimited by membrane 4 and reservoir 5.

The intake body 2 is obtained, except the sealing gasket 13, by molding a relatively plastic rigid and transparent, and then molded there, on this piece, the gasket 13 which is made of elastomer, being taken to Perform this overmolding in the example illustrated by bijection.

The evacuation body part 3 represented in figure 4 it is also made of relatively molded plastic  rigid, in this case white, being equipped to then this part, by simple adjustment, with the plate porous 48.

In order to mount the intake body 1, the evacuation body 3 and membrane 4, the last one is put on the plateau 30, concentrically with it, then the body of admission 2 facing the evacuation body 3 with the pins of hitch 7 aligned with the openings 44, then pressed strongly the body 2 towards the body 3 so that the pins 7 fit into openings 44 by slightly flexing in by virtue of the inclined surface 21 that acts as a ramp, allowing the force exerted that surface 22 of shoulder 24 pass over tooth 45 at the end of the thrust with movement, in under the spring of the pins 7, relaxing slightly to then the seal 13 so that it recovers completely the gap between the pins 7 and the skirt 31, maintaining the elasticity of the seal 13, which compress then the blockage thus obtained.

It should be noted that the maintenance of the gasket in compressed state allows to offer an excellent sealing between the membrane 4 and the edge of the wall 9, and also, by reaction, between the membrane 4 and the surface 33.

It should also be noted that the surface internal wall 16 has localized areas of additional thickness 27 (figure 3) that come into contact with the external surface of the wall 41, which provides a lateral key between these surfaces, which are of similar diameter, and more generally between bodies 2 and 3.

Finally, it should be noted that once that device 1 has been mounted in this way, it is possible package it and sterilize it with a gas such as ETO (oxide of ethylene) or by irradiation.

Naturally, before packing the device assembled 1 and sterilize it, each of the tubes 10 and 37 is Equipped with a plug.

It will now explain the way in which it takes take the sampling of a liquid under pressure with the device 1.

First of all, remove the cap that closes one of the tubes 10 and the cap that closes the tube 37, then the tube without plug 10 to a source of liquid under pressure, for example using, as shown in figure 7, a socket connector samples 60 which has a male Luer tip 61, which is inserted into the passage of the tube without plug 10 and the valve 62 of the connector 60, so that the chamber formed by the reservoir 5 and the membrane 4 is placed at the same pressure as the liquid, by example, 3 bars, liquid entering the tank 5 through the opening 11 and leaving the tank passing through the membrane 4 which rests on the porous plate 48, the liquid being guided which has passed through membrane 4 through channels 39 to the opening 38, the liquid from the device 1 coming out of the tube 37, preferably having a graduated container under the device 1 to recover the liquid leaving the tube 37 to know when the volume 4 has passed through the membrane Required for the sample.

When this volume has been reached, it closes the valve 62 and the device 1 is separated from the connector 60, it then put in its place, in the tube without plug 10, a filter of air sterilization 63 (represented in figure 10 but not in Figure 8), and the evacuation of the liquid still present mainly in tank 5 by suction through the outlet opening 38.

In the example shown in Figure 8, perform evacuation with a syringe or pump 64 that has a connector 65 provided with a suction tip 66 that has been inserted in the passage of the tube 37, the liquid being ejected by the tip 67 sucked out by tip 66 when the stem is pushed 69 inside the body 68, exerting pressure on the plunger 70.

It should be noted that samples 47 made on the wall 43 make it possible to correctly place the pump or the syringe 64 in relation to device 1, in four positions at 90º to each other, showing two of these positions in Figure 8

Another possibility to extract the liquid that remains in device 1 after sampling consists in using a vacuum flask, as shown in figure 10.

The vacuum flask 71 illustrated includes a glass body 72 which has, at the level of its neck a tube 73 connected, in a manner not shown, to a vacuum pump and, in the top of this neck, a flexible cap 74 with a central opening 75 made therein, the bottle being 71 of a type which is currently in practice.

Device 1 is simply placed in the cap 74, with the tube 37 inserted in the opening 75 and the rib 40 supported on the top of the cap 74.

Because of the narrow profile of nerve 40, the last deforms the cap 74 locally and provides sealing that It makes it possible to suction the residual liquid when it is aspirated.

Once the remaining liquid has been discharged that is in device 1, it can be opened, what is done breaking the four hook pins 7, by simple pressure on said pins through the respective notches 46, such as it is explained in the foregoing and illustrated in figures 11 and 12.

It is then possible to separate the body from intake 2 of the evacuation body 3 and collect the membrane 4, by example, with sterilized tweezers 80, as shown in the figure 13, then deposit the membrane through which the Sample to be examined, in a Petri dish 81, as shown in the figure 14, and then conventionally perform the incubation of the Petri dish / membrane set.

It should be noted that the surface concavity 35 so that the ratio of the difference between the length of the arc corresponding to the profile, in a diametral plane, of the surface of the plate 48 that faces the membrane 4 and between the length of the string of this bow, about the last length corresponds to the expansion coefficient of the membrane 4 between the dry state and the wet state.

The result of this is that the dilation of the membrane 4, when it changes from the dry state to the wet state, corresponds precisely to the difference in length between the arc corresponding to the aforementioned profile and the rope of this arc, so that in the wet state the membrane 4 is supported perfectly on plate 48, without folding. Therefore, the plate 48 provides a particularly effective support for the membrane 4 when subjected to the pressure difference that allows Let the liquid flow through it.

In addition, when the user recovers membrane 4 with the tweezers 80 as shown in figure 13, this membrane It has a concave shape, on the side where the tank 5 is located, that is, on the side where they are considered to be present any microorganisms retained by the membrane in the time of sampling, thus being the curvature of the membrane 4 in the correct direction when placed in the surface of culture medium 82 in plate 81.

This is because, when the membrane 4 it is placed in the plate 81, it is the convex side of the membrane 4 the one that looks towards the surface of the medium 82, so that, placing the membrane 4 on the medium 82 from a portion of the membrane opposite the tweezers 80 and moving it so that the membrane progressively coming into contact with the medium 82 to the place in which it is maintained by the tweezers. The risk of membranes have one or more gaps on the opposite side with respect to the medium 82 and, therefore, the risk of developing one or more air cavities between the membrane 4 and the medium 82 are thus null or in any case minima.

Culture medium 82 in plate 81 illustrated in figure 14 is a culture medium containing agaragar, used in the solid state after being poured into the plate hot.

If it is desired to use a liquid culture medium, it is possible to replace the Petri 81 dish with a similar dish but with one in which the agaragar 82 culture medium is replaced by a absorbent plate impregnated by the liquid culture medium.

Another possibility, instead of cultivating microorganisms outside of device 1, is to inject medium of liquid culture in it using one of the tubes 10, evacuating then the excess culture medium used by tube 37, and put then the device 1 to incubate directly, being membrane 4 recovered only to identify and count the microorganisms after incubation.

In such a case, there is an advantage in the use of a liquid culture medium that is slightly more concentrated that the conventional medium since it always remains, mainly in the plate 48, a certain amount of sampled liquid that mixes with the injected culture medium that is therefore diluted.

In variants, not represented, is the body of evacuation 3, and not the intake body 2, the one with the gasket of elastomer such as sealing gasket 13 described in what precedes; the male and female coupling elements between bodies 2 and 3 are provided, respectively, in the body of evacuation 3 and in the intake body 2, instead of the other way around; and / or different type of coupling means, locking means are used that have means of articulation between bodies 2 and 3 and means of coupling opposite to the means of articulation, or means of Locking other than hitch.

Claims (32)

1. Device for microbiological examination of a sample of liquid under pressure, which has an intake body, a filtration membrane and an evacuation body, said admission body having a reservoir, in a wall of which an inlet opening is made of liquid, said membrane closing said reservoir, said evacuation body having means for supporting said membrane on the opposite side with respect to said reservoir and a liquid outlet opening, said intake body and said evacuation body having molded locking means of integral manner, characterized in that said membrane (4) is annularly fastened at the periphery between a first member (9) that is part of said intake body (2) and a second member (32) that is part of said evacuation body ( 3), one of said first member and said second member having an elastomer seal (13) by means of which it comes into contact with said m embrana (4), and because said blocking means (7, 31) are adapted to allow the opening of said device requiring only a separation movement between said first member (9) and said second member (32), said means having blocking axial engagement means (7, 31) between the intake body (2) and the evacuation body (3), with one of the intake body (2) and the evacuation body (3) having at least one engagement pin axially oriented (7), while the other has means (42, 44, 45) to receive said hitch pin (7), and because the hitch pin (7) extends protruding from the edge of a skirt (6) which is part of the one of said intake body (2) and said evacuation body (3) that includes it. Device according to claim 1, characterized in that the membrane (4) is maintained exclusively because it is annularly fastened at the periphery between said first member (9) and said second member (32). Device according to any one of claims 1 or 2, characterized in that said sealing gasket (13) is molded on the one of said first member (9) and of said second member (32) which includes it. Device according to any one of claims 1 to 3, characterized in that it is the first member (9) that has said elastomer seal (13). Device according to claim 4, characterized in that said first member (9) forms a side wall of said reservoir (5) of the intake body (2), said wall (9) terminating at one end at an edge that forms part of said gasket (13). Device according to claim 5, characterized in that a groove (14) is formed at the end of a rigid part of said side wall (9), while said gasket (13) has a T-shaped profile whose longitudinal branch it forms a rib (50) inserted in said groove (14) and whose transverse branch forms a cushion (51) that is in contact with the membrane (4). Device according to claim 6, characterized in that there is a bevel (54) between the rib (50) and the cushion (51) on the outer side, while, on the inner side, the rib (50) and the cushion ( 51) are connected by a straight surface. Device according to any one of claims 6 or 7, characterized in that said cushion (51) has two annular lips (53). Device according to any one of claims 1 to 8, characterized in that said hitch pin is connected to the rest of one of said intake body (2) and said evacuation body (3) which includes it, by means of a frangible zone . Device according to claim 9, characterized in that said frangible zone is located in the region of a dihedron (20) on one of the surfaces (19) of said hitch pin (7). Device according to claim 10, characterized in that said surface (19) having a dihedron (20) is located on the inner side of the hitch pin (7). 12. Device according to any one of claims 1 to 11, characterized in that the one of said intake body (2) and said evacuation body (3) having means for receiving said engagement pin (7) has a wall ( 42) oriented transversely and provided with an opening (44), through which the hitch pin (7) can pass, said pin and said wall (42) having means (23, 24, 25) to prevent the withdrawal of the pin (7) once it has been correctly inserted into the opening (44). 13. Device according to claim 12, characterized in that said means for preventing the withdrawal of the hitch pin (7) have on said wall (42) an axially oriented tooth (45) that borders said opening and which has on said pin of hook a groove (23) adapted to accommodate said tooth (45). 14. Device according to claim 12 or claim 13, characterized in that said transversely oriented wall (42) is connected to a side wall (43) extending on the opposite side of one of said intake body (2) and said evacuation body (3) having the hitch pin (7), the dimension in the axial direction of said side wall (43) being greater than the dimension in the axial direction of the hitch pin (7). 15. Device according to claim 14, characterized in that in said side wall (46), at the level of said opening (44), a notch (46) is made, to make it possible to exert pressure on said hitch pin (7). 16. Device according to any one of claims 1 to 15, characterized in that it is the intake body (2) that has the hitch pin (7), and that it is the evacuation body (3) that has the means ( 42, 44, 45) to receive said hitch pin (7). 17. Device according to any one of claims 1 to 16, characterized in that the one of said intake body (2) and said evacuation body (3) has a plurality of said engagement pins (7). 18. Device according to claim 17, characterized in that it has four hook pins (7). 19. Device according to any one of claims 1 to 18, characterized in that said locking means exclusively comprise said axial engagement means (7, 31). 20. Device according to any one of claims 1 to 19, characterized in that said evacuation body (3) has a circular plateau (30) provided at its center with means (48) for supporting said membrane (4) and having, around of said support means (48), a wall (32) that includes a surface (33) located facing said elastomer seal (13), which forms part of said intake body (2), said membrane being compressed ( 4) between said surface (33) and said gasket (13). 21. Device according to claim 20, characterized in that said support means (48) have a concave surface facing said membrane (4). 22. Device according to claim 21, characterized in that the ratio of the difference between the length of the arc corresponding to the profile, in a diametral plane, of said surface of said support means (48) and between the length of the rope of this arc , over the last length, corresponds to the coefficient of expansion of said membrane (4) between the dry state and the wet state. 23. Device according to any one of claims 20 to 22, characterized in that said support means are formed by a porous plate (48). 24. Device according to claim 23, characterized in that said evacuation body (3) has evacuation channels (39) under said porous plate (48), said evacuation channels opening within said exit opening (38). 25. Device according to any one of claims 20 to 24, characterized in that the external diameter of said circular plateau (30) substantially corresponds to the internal diameter of a skirt (6) included in said intake body (2), surrounding said skirt ( 6) to said circular plateau (30). 26. Device according to claim 25, characterized in that between said circular plateau (30) and said skirt (6) additional thickness areas are provided for keyway (27). 27. Device according to any one of claims 20 to 26, characterized in that said evacuation body has a skirt (31) arranged in a step with respect to said circular plateau (30). 28. Device according to claim 27, characterized in that said skirt (31) has engagement means (42, 44, 45) with said intake body (2). 29. Device according to any one of claims 27 or 28, characterized in that said skirt (31) of the evacuation body (3) has at least one notch (47) adapted to allow the placement of an evacuation syringe (64). 30. Device according to any one of claims 1 to 29, characterized in that said outlet opening (38) of the evacuation body (3) is in continuation of the internal passage of a coaxially arranged outlet tube (37). 31. Device according to claim 30, characterized in that said evacuation body (3) has, around said outlet tube (37), an annular rib (40) that narrows towards its end. 32. Method for evacuating a device according to claim 31, characterized in that it is placed in a vacuum bottle (71) with said outlet tube (37) applied in the central hole (75) of the cap (74) of said bottle and said annular nerve (40) resting on this plug.