Abstract:
A sampling device includes a body, a needle, a sealing element and an element for feeding and removing a liquid. The needle has at least one groove located between the sealing element and the sampling end of the needle. The sampling end has a sampling hole opening out on a lateral wall of the end. The sampling device leakage problems encountered in the conventional art to be overcome while at the same time resolving the problems of placing the inside of a tube containing a product to be analyzed at atmospheric pressure.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a sampling device which can be used in an analysis automated device. It also relates to a process for taking samples and/or sampling implementing a device according to the invention. 
     DESCRIPTION OF THE CONVENTIONAL ART 
     The field of the invention is the field of sampling automated and/or injection devices and more particularly analysis automated devices. 
     In general, tubes containing products to be analyzed which are used in analysis automated devices are tubes with a stopper, usually made of elastomer. These tubes are increasingly placed under a relative vacuum in order to facilitate the filling of these tubes. For example, when taking blood samples, tubes are used in which a relative vacuum is created to avoid the use of a syringe. In analysis automated devices, sampling and injection operations are carried out by passing a suitable needle through the stopper without removing the stopper from these tubes. Now, the differences in pressure between the inside and the outside of the tube cause difficulties when sampling the product contained in these tubes. Moreover, when the needle passes through the stopper, the deformations of the stopper and the penetration of the needle into the tube increase the pressure fluctuations in these tubes. 
     All of these variations in pressure can reduce the accuracy of the quantities taken from or injected into these tubes. Current systems and devices recommend the use of specific needles to try to resolve these problems. Thus, the patent FR 2 767 583 proposes the use of a needle having a cutting tip on the one hand and a slot, hollow or groove on its external surface on the other, allowing the inside of the tube to be placed at atmospheric pressure by the circulation of air between the outside and the inside of the tube thanks to the groove. 
     However, such a needle poses several problems. Firstly, the presence of a groove on its outside surface poses risks of leakage of the product handled during a sampling operation. Secondly, the cutting tip of the needle poses a risk to the operators required to handle it that they may be pricked by it. 
     Moreover, sampling automated devices have feed circuits for diluents used during the analysis of a sample taken or for products intended to clean the needle. Such cleaning operations are frequent and are of prime importance in order not to contaminate the products to be analyzed by each other or by analysis products. Now, the use of a needle with a groove on its outside surface, such as that described in the patent FR 2 767 583, poses the problems of leaking via this slot of the diluent on the one hand and of the product intended to clean the needle on the other. 
     SUMMARY OF THE INVENTION 
     An aim of the invention is to propose a sampling device which allows the leakage problems described above to be overcome while at the same time resolving the problems of placing the inside of the tube at atmospheric pressure. 
     An aim of the invention is to propose a sampling and/or injection device which poses less danger of pricking the operator than the current devices. 
     The invention proposes to deal with the above-mentioned problems by a sampling device which can be used in an automatic analysis device, this device comprising:
         a body,   a sampling needle that can move in the body between an extended position suitable for taking a sample and a retracted position, the needle having a sampling end and at least one groove extending longitudinally over its outside surface, and   sealing means between the body and said outside surface of the needle; the groove extending between the sealing means and the sampling end regardless of the position of the needle between its extended position and its retracted position. Through the combined use of at least one groove on the outside surface of a needle and sealing means, the device according to the invention advantageously provides solutions:   on the one hand to the problems of accuracy with regard to the quantities sampled or injected by the needle by placing under atmospheric pressure the internal volume of the tube in which the sampling (and/or injection) is (are) carried out; and   on the other hand to the problems of leakage of dilution product or cleaning products via the groove.       

     In a particular embodiment of the device according to the invention, the needle can have at least one second groove arranged such that in the retracted position the sealing means are arranged between the first and the second groove, said first and second grooves each defining a respective grooved zone and a sealing zone between them. 
     In fact, to ensure that a sampling will be carried out in the tube even if it contains little product, the needle is moved close to the bottom of the tube. Thus, it may be that the first groove has penetrated the tube beyond the stopper, no longer ensuring the circulation of air. This is not generally a problem, because the volumes sampled are small. However, if it is desired to sample a greater quantity, the second grooved zone, provided to pass through the stopper in the extended position, then allows the circulation of air to resume. 
     Of course, the needle can have several grooved zones, separated from each other by a respective sealing zone. 
     Advantageously, the device according to the invention can have several grooves on its outside surface, the number of grooves being able to be determined depending on the sought use. 
     The dimensions of the groove, and more particularly the length and the depth of the groove must be such that, when the stopper is pierced, the deformation of the latter does not block the groove and thus does not prevent the internal volume of the tube from being placed at atmospheric pressure. 
     In a particular embodiment, the groove can have a rectangular, triangular, rounded or trapezoidal or even dovetail section, each of these sections having its own technical effects. For example, a rounded section facilitates the cleaning of the needle and more particularly of the grooves, whereas a square, rectangular or also trapezoidal section allows a more effective application of atmospheric pressure. Moreover, each of the sections presents lesser or greater production problems. 
     The sealing means are placed in an internal volume of the body of the device according to the invention. Thus, in a way, they allow the internal volume of the body to be divided into two parts:
         one part, termed downstream, corresponding to the part of internal volume situated beyond the sealing means in the direction of the sampling end of the needle and,   one part, termed upstream, corresponding to the remainder of the internal volume of the body.       

     The task of the sealing means is to produce the seal between the downstream part and the upstream part. They are arranged so as to be in contact with the outside surface of the needle on the one hand and with an inside surface of the body of the device on the other. The contact between the sealing means and the needle is adjusted such that the needle can slide along it. 
     The sealing means can advantageously include at least one sealing ring. 
     The sealing means can advantageously rest on at least one shoulder of the body. The sealing means can also be mounted, clamped or not, between two shoulders or a slot, or shapes which project into the internal volume of the body of the device. 
     Advantageously, the device according to the invention can moreover comprise means ( 122 ) for feeding and/or means ( 121 ) for removing a given liquid in the volume downstream of the body of the device according to the invention. These means can comprise at least one circuit feeding and one circuit removing the given liquid. In a particular version of the device according to the invention, the feed circuit and the removal circuit can have parts in common. The feed and/or removal means can moreover comprise means for pushing or aspirating a liquid in the feed and/or removal circuits, such as pumps, valves. These means can moreover comprise means for blocking the feed and/or removal circuits when these circuits are not in use. 
     In a particular version of the device according to the invention, the fed liquid can comprise a liquid under pressure. 
     In another particular version of the device according to the invention, the fed and/or evacuated liquid can comprise a cleaning product and/or a product for rinsing the needle. In this particular configuration, the device according to the invention can be placed above a cleaning tank provided to recover part of the product during a rinsing and/or cleaning operation. In this configuration, the needle is preferably located in a retracted position so that the cleaning and/or rinsing product comes directly into contact with the downstream part of the needle to be cleaned and/or rinsed. 
     According to another particular version of the device according to the invention, the liquid can comprise a dilution product intended to be added to a vessel containing a sample taken from a tube with a view to submitting it to various analyses. 
     The liquid can also comprise a test reagent potentially intended to react with the sample taken within the scope of an analysis. 
     Advantageously, on the side of the sampling end of the needle, the groove ends at a distance from said end. This distance can be a function of the shape of the sampling end, as well as of the dimensions of the end, and such that the sampling end is sufficiently resistant to pass without being damaged through the stopper of the tube containing the product to be analyzed. The stress exerted on the needle during the piercing of the stopper must not damage the needle. 
     In a particular version of the device according to the invention, the sampling end of the needle can be rounded. Such a rounded end allows to reduce the risks of an operator being pricked by the needle when he is required to use it. 
     However, in another particular version of the device according to the invention, the end of the needle can be pointed, and more particularly the needle can have a sampling end with a cutting edge, this cutting edge being connected to the substantially cylindrical body of the needle by at least one or more faces, at least one of these faces having a sampling hole. 
     Advantageously, the sampling end of the needle can have at least one hole opening out laterally on the surface of the needle. Such a hole thus makes it possible, firstly to prevent a piece from being cut from the stopper of a tube during perforation of this stopper, and secondly the blocking of the needle by the piece cut from the stopper, which is the case in the majority of needles in the prior art having a hole at the end of the needle. Moreover, such a hole allows a greater accuracy with regard to the quantity of the product sampled by the device according to the invention. 
     Surprisingly, it appears that the grooves of the needle improve the cleaning performance in respect of this needle. 
     According to another feature of the invention, a method which uses the device according to the invention is proposed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       Other advantages and characteristics will become apparent on examination of the detailed description of an embodiment that is in no way limitative, and the attached drawings in which: 
         FIG. 1  is a diagrammatic section representation of a device according to the invention, the sampling needle of the device being in a retracted position; 
         FIG. 2A  is a diagrammatic section representation of a device according to the invention, the sampling needle of the device being in an extended position; 
         FIG. 2B  is a diagrammatic section representation of a device according to the invention, the sampling needle of the device having two grooved zones and being in an extended position; 
         FIG. 3  is a diagrammatic section representation of four needles having grooves with different sections, which can be used in the device according to the invention; 
         FIG. 4  is a diagrammatic section representation of four needles, each having a different number of grooves, which can be used in the device according to the invention; 
         FIG. 5  is a diagrammatic section representation of three needles, each having a sampling end with a different shape. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The example described above is a particular non-limitative application of a device according to the invention. 
       FIG. 1  is a diagrammatic section representation of a sampling device according to the invention comprising a body  14 , a needle  10 , sealing means  11 , and means  121  and  122  for feeding and removing a liquid in the internal volume of the body  14  of the device. The sampling needle  10  is provided with a sampling end  103 . Partially represented on  FIG. 1  is a tube  13  having a stopper  131 . In this figure, the sampling needle is in a retracted position, i.e. the sampling end  103  is located inside the body  14 . 
     In addition, this needle  10  has two grooves  101  on its outside surface and a hole  102 . The grooves  101  are located between the sealing means  11  and the sampling end  103  of the needle  10 . Indeed, the grooves  101  do not extend over the whole length of the needle and are present only on a limited part of the needle  10 . This limited part is located between the sampling end  103  and the sealing means  11  regardless of the position of the needle between the retracted position represented in this  FIG. 1  and the extended position allowing a sample intended for analysis to be taken (see  FIGS. 2A and 2B ). The grooves  101  are therefore located beyond the sealing means in the direction of the sampling end  103 . 
     The sealing means  11  are placed in an internal volume of the body  14  of the device according to the invention. They allow the internal volume of the body  14  to be divided into two parts:
         one part  16 , termed downstream, corresponding to the part of the internal volume of the body  14  situated beyond the sealing means  11  in the direction of the sampling end  103  of the needle  10  and,   one part  15 , termed upstream, corresponding to the remainder of the internal volume of the body  14 .       

     The task of the sealing means  11  is to create the seal between the downstream part  16  and the upstream part  15 . They are arranged so as to be in contact with the outside surface of the needle  10  on the one hand and with an inside surface of the body  14  of the device on the other. The contact between the sealing means  11  and the needle  10  is adjusted so that the needle  10  can slide along it. 
     In the particular example described here, the sealing means constitute a sealing ring. The sealing ring rests on a shoulder  19  of the body  14  of the device. 
     The device also has a feed circuit  122  and a removal circuit  121  for a given liquid in the downstream part  16 . The device can also have means for pushing or for aspirating (not shown) a product in the feed and/or removal circuits, such as pumps and valves. In addition, these means can comprise means for blocking the feed circuit  122  and/or the removal circuit  121  when they are not in use. Of course, in another embodiment, the circuit  121  can serve as a feed circuit for a liquid in the downstream part and the circuit  122  as a removal circuit for this liquid. 
     The liquid fed into the downstream part  16  can be under pressure. It can be a cleaning product or a dilution product. In the case where the liquid fed by the feed circuit  122  is a cleaning product, the device is placed above a reception tank (not shown) provided to receive all or part of the cleaning product. The cleaning product can also be removed by the removal circuit  121  creating a vacuum at the downstream part  16  of the internal volume of the body. In the case where the liquid fed by the feed circuit  122  is a diluent product the device is placed above a vessel (not shown) intended to receive the product in question. The task of the sealing means  11  is to ensure the sealing of the downstream part  15  of the internal volume of the body  14  of the device vis-à-vis products fed by the feed means  122  in the downstream part. 
     In  FIG. 2A , the device according to the invention is shown with the sampling needle  10  in an extended position. More precisely, the needle  10  is shown after perforation of the stopper  131  of the tube  13  by the needle  10 . During the perforation of the stopper  131  of the tube  13 , the inside of the tube  13  is placed at atmospheric pressure by the circulation of air through the grooves  101 . 
     Moreover, the needle  10  has a sampling hole  102  on the lateral wall of the sampling end  103  and near the tip of this end  103 . The positioning of this hole  102  makes it possible, firstly to prevent a piece from being cut from the stopper  131  of a tube  13  during the perforation of this stopper and the blocking of the hole  102  with the piece in question, and secondly to take a sample  17  of the product  18  to be analyzed with great accuracy with regard to the quantity sampled in the needle  10 . 
     The grooves  101  end at a distance from the sampling end  103 . This distance can be a function of the shape of the sampling end  103  as well as of the dimensions of the end  103  and such that the sampling end  103  is sufficiently resistant to pass without being damaged through the stopper  131  of the tube  13  containing the product  18  to be analyzed. The stress exerted on the needle  10  during the piercing of the stopper must not damage the needle  10 . 
       FIG. 2B  is a diagrammatic section representation of a device according to the invention. In  FIG. 2B , the sampling needle  10  is in a sampling position. The sampling end  103  of the needle  10  is located close to the bottom of the tube  13  containing the product  18  to be sampled. The needle  10  has two grooved zones  104  and  105 . The first grooved zone  104  allows the inside of the tube  13  to be placed at atmospheric pressure during the piercing of the stopper  131  of the tube  13  by the needle  10 . The second grooved zone  105 , comprising the grooves  106 , passes through the stopper of the tube  13  in order to allow a circulation of air between the inside and the outside of the tube  13  so as to avoid the vacuum created by the sampling of a large quantity of product  18 . When the needle  10  is in its retracted position, the sealing means are arranged between the first grooved zone  104  and the second grooved zone  105 . 
     As shown in  FIG. 3 , the needle  10  can have grooves  31  with a square or rectangular section, grooves  32  with a circular section, grooves  33  with a triangular section, and/or grooves  34  with a trapezoidal and more particularly dovetail section. Each of these sections has its own technical effects. For example, a rounded section facilitates the cleaning of the needle and more particularly of the grooves, whereas a square, rectangular or also trapezoidal section allows atmospheric pressure to be created more effectively to the inside of the tube  13 . 
       FIG. 4  is a diagrammatic representation of a needle  41  having a single groove. Also shown in  FIG. 4  is a needle  42  having 2 grooves, a needle  43  having 3 grooves and a needle  44  having 4 grooves. 
     Moreover, the sampling end  103  of the needle  10  can have a rounded shape  51  as shown in  FIG. 5 . Such a rounded end  51  allows to reduce the risk of an operator being injured, and more particularly being pricked, by the needle when he is required to handle it. 
     However, in a particular version of the device according to the invention, the end of the needle can have a pointed shape  52  and  53 . More particularly, the needle can have a sampling end with a cutting edge, this cutting edge being connected to the substantially cylindrical body of the needle by at least one or more faces, at least one of these faces having a sampling hole. 
     Of course, the device according to the invention is not limited to the example just described. The number, arrangement and shape of the grooves of the needle can vary. The needle can have a sampling end with a section that is different from those described within the scope of the description of the particular example above. The sampling needle can be moved in a circular motion. The sealing means can be fixed by means of a slot or several shoulders. Finally, the sampling needle can have several sampling holes.