Abstract:
A directional control valve for fluid comprising an axial chamber connected to first and second radial inlet/outlet ports and to a radial outlet port for administering said solution, a rotary crank pin housed in said chamber and through which there pass connecting ducts which are connected to axial third and fourth inlet/outlet ports intended to be connected to said second reservoir, said connecting ducts being designed to connect said first, second, third, fourth inlet/outlet ports and said administering port selectively and fluidically according to the angular position of said crank pin with respect to said body.

Description:
TECHNICAL FIELD 
     The invention relates to a directional control valve for fluid that is adapted to make up a solution in situ by mixing two ingredients coming from a first reservoir and from a second reservoir, the valve comprising: a body defining an axial chamber and being provided with radial first and second inlet/outlet (I/O) ports designed to be connected to the first reservoir and to a feed pump, and with a radial administering port adapted to enable the solution to exit, the first and second I/O ports and the administering port communicating with the chamber; and a rotary spool received in the chamber and through which link channels pass, the spool being provided with axial third and fourth I/O ports designed to be connected to the second reservoir and communicating with the link channels, the link channels being arranged to interconnect the first, second, third, and fourth I/O ports and the administering port selectively and for fluid flow, depending on the angular position of the spool relative to the body so that, in a first angular position, they connect the first I/O port to the third I/O port, and close off the second I/O port and the fourth I/O port so that, by means of the feed pump, they enable the ingredient to be transferred between the first reservoir and the second reservoir. 
     The invention also relates to in-situ making-up and administering apparatus for making up in situ and for administering a solution obtained by mixing two ingredients coming from first and second reservoirs, the in-situ making-up and administering apparatus including a directional control valve for fluid, the valve comprising a body and a spool mounted to move in rotation in said body, motor-drive means for driving the spool, and a fluid-flow circuit element arranged to interconnect the first and second I/O ports. 
     PRIOR ART 
     It is frequently necessary to mix ingredients so as to make up and homogenize a solution immediately before it is used. This applies, in particular to solutions for therapeutic purposes, in the medical or veterinary fields, or for other purposes, e.g. in the cosmetics field. Mixing or making up solutions immediately before they are used is very useful when the solution is unstable once it has been mixed or made up. This applies particularly for new therapeutic molecules of biological origin which can be preserved mainly only in the form of solid powder to be put in suspension, or in lyophilized (freeze-dried) form, or to be made up immediately before administering. To make up such a solution, for example, a first ingredient in the form of a solid powder, or in a lyophilized, dehydrated, or concentrated form, is used with a second ingredient of the solvent type. In order to obtain a homogeneous solution, the making-up requires a specific protocol to be followed. Once obtained, the solution can be administered by any suitable means. The term “administering” is used, in particular, to cover any act making it possible to have an ingredient absorbed by a user, be it by injection, perfusion, oral route, cutaneous route, or by any other suitable means. 
     Four to ten manual steps can be necessary to make up a solution, requiring the use of one or more syringes, bottles, needles and the like for successively:
         taking a first ingredient from a first bottle by using a first syringe;   transferring the taken ingredient to a second bottle containing a second ingredient, by using the first syringe, while avoiding emulsion or clumping effects during the transfer;   blending the first and second ingredients in order to obtain a homogeneous solution of the mixture of the first and second ingredients;   taking the solution by using the same syringe or by using a second syringe; and   administering the solution by using the same syringe as used during the taking, but generally equipped with a new needle that is specifically adapted to injection.       

     In order to guarantee satisfactory hygiene conditions, the syringes and bottles need to be sterile, which is a considerable constraint. In addition, a predetermined waiting time must be left between the making-up steps. Furthermore, repeated use of syringes having needles increases the risks of injury to the personnel doing the making-up. Finally, making up certain solutions involves cytotoxic substances, use of which requires air extraction installations and atmosphere monitoring installations. Such installations represent a non-negligible additional cost and can be used only in specific dedicated locations, which does not make it possible for them to be used in the majority of situations of use. Thus, making up solutions and administering them must be performed by medical personnel. 
     Thus, it is necessary to propose making-up apparatus of the “closed” type, enabling making-up to take place without any risk of contamination from liquid, powder, or vapor, and making it possible to guarantee a good level of asepsis. There is thus a genuine need for making-up apparatus that is simple and reliable to use, and that can be operated by people without any medical training, and that optionally makes it possible to administer the resulting made-up solutions. 
     In order to make up a solution from two ingredients, it is possible to use directional control valves of the 6/3 type, namely of the type having six ports and three positions, such as the directional control valve described in Publication WO 2012/085 428. Unfortunately, the construction of such directional control valves makes them complicated to manufacture. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to mitigate the drawbacks of existing directional control valves for fluid by proposing a valve that is of simple construction, that makes it possible to make up a homogeneous solution comprising a mixture of two ingredients, and that is easy to use by a user who does not have any medical training, the valve optionally being incorporated in apparatus for mixing a solution and for administering the resulting solution, e.g. by injection. 
     To this end, the invention provides a directional control valve for fluid that is adapted to make up a solution in situ by mixing two ingredients coming from a first reservoir and from a second reservoir, the valve comprising: a body defining an axial chamber and being provided with radial first and second inlet/outlet (I/O) ports designed to be connected to the first reservoir and to a feed pump, and with a radial administering port adapted to enable the solution to exit, the first and second I/O ports and the administering port communicating with the chamber; and a rotary spool received in the chamber and through which link channels pass, the spool being provided with axial third and fourth I/O ports designed to be connected to the second reservoir and communicating with the link channels, the link channels being arranged to interconnect the first, second, third, and fourth I/O ports and the administering port selectively and for fluid flow, depending on the angular position of the spool relative to the body so that, in a first angular position, they connect the first I/O port to the third I/O port, and close off the second I/O port and the fourth I/O port so that, by means of the feed pump, they enable the ingredient to be transferred between the first reservoir and the second reservoir, said valve being characterized in that the link channels are arranged so that:
         in a second angular position, said link channels connect the first I/O port to the third I/O port and connect the second I/O port to the fourth I/O port so that, by means of the feed pump, they enable the mixture to be transferred and blended between the first and second reservoirs; and   in a third angular position, said link channels connect the first I/O port to the administering port, and close off the second I/O port, the third I/O port, and the fourth I/O port so that, by means of the feed pump they enable the resulting solution to be administered.       

     In the present specification, the terms “first”, “second”, and “third” are used in non-limiting manner to distinguish between similar elements. 
     The basic idea lying behind the invention is to provide a particular configuration for the link channels that makes it possible to obtain a directional control valve of the 5/3 type, namely having five ports and three positions, that is of simple design and that is simple to use. 
     In a first embodiment of the valve of the invention, the link channels comprise the following three link channels:
         a first link channel in the shape of an upside-down T having its central branch provided with the third I/O port, having a first radial branch provided with a first radial opening, and having a second radial branch provided with a second radial opening, the first link channel being arranged so that:
           in the first angular position, the first radial opening is situated in register with the first I/O port and the second radial opening is closed off by the wall of the chamber;   in the second angular position, the second radial opening is situated in register with the first I/O port and the first radial opening is closed off by the wall of the chamber; and   in the third angular position, the first and second radial openings are closed off by the wall of said chamber;   
           a second link channel in the shape of an upside-down L having its long bar provided with the fourth I/O port and having its short bar provided with a radial opening, the second link channel being arranged so that:
           in the first and third angular positions, the first radial opening is closed off by the wall of the chamber; and   in the second angular position, the radial opening is situated in register with the second I/O port;   
           a third link channel passing radially through the spool and provided with a first radial opening and with a second radial opening, the third link channel being arranged so that:
           in the first and second angular positions, the first and second radial openings are closed off by the wall of said chamber; and   in the third angular position, the first radial opening is situated in register with the first I/O port and the second radial opening is situated in register with the administering port.   
               

     The first embodiment of the valve of the invention may have the following features:
         the axes of the first and second radial openings of the first link channel, of the first radial opening of the third link channel and the first I/O port lie in a first radial plane;   the axes of the radial opening of the second link channel and the second I/O port lie in a second radial plane distinct from the first radial plane; and   the axis of the second radial opening of the third link channel and the administering port lie in a third radial plane distinct from the first and second radial planes.       

     The first embodiment of the valve of the invention may have the following features:
         the first I/O port, the second I/O port, and the administering port are situated in the same midplane of the body, and the first and second link channels are situated in the same first axial plane of the spool; and   the third link channel is situated in a second axial plane of the spool that is offset angularly by 90° relative to the first axial plane;       

     so that going between the first and second angular positions is obtained by turning the spool through a half-turn in the body and so that, going between the first and third positions and going between the second and third positions is obtained by turning the spool through respective quarter-turns in the body. 
     In second and third embodiments of the valve of the invention, the link channels comprise the following two link channels:
         a first link channel in the shape of an upside-down L that is provided with a plurality of short bars, that has its long bar provided with the fourth I/O port, that has a first one of its short bars provided with a first radial opening, that has a second one of its short bars provided with a second radial opening, and that has a third one of its short bars provided with a third radial opening, the first link channel being arranged so that:
           in the third angular position, the first, second, and third radial openings are closed off by the wall of said chamber;   in the second angular position, the second radial opening is situated in register with the first I/O port and the first and third radial openings are closed off by the wall of the chamber; and   in the third angular position, the third radial opening is situated in register with the first I/O port, the first radial opening is situated in register with the administering port, and the second radial opening is closed off by the wall of the chamber;   
           a second link channel in the shape of an upside-down T that is provided with a plurality of radial branches, that has its central branch provided with the third I/O port, that has a first one of its radial branches provided with a first radial opening, that has a second one of its radial branches provided with a second radial opening, and that has a third one of its radial branches provided with a third radial opening, the second link channel being arranged so that:
           in the first angular position, the first radial opening is situated in register with the second I/O port and the second and third radial openings are closed off by the wall of the chamber; and   in the second angular position, the second radial opening is situated in register with the second I/O port and the first and third radial openings are closed off by the wall of the chamber; and   in the third angular position, the third radial opening is situated in register with the second I/O port and the second and third radial openings are closed off by the wall of the chamber.   
               

     In the second embodiment, the directional control valve for fluid may have all of the following features:
         the axes of the second and third radial openings of the first link channel and the first I/O port lie in a first radial plane;   the axes of the first, second and third radial openings of the second link channel, and the second I/O port lie in a second radial plane; and   the axis of the first radial opening of the first link channel and the administering port lie in a third radial plane distinct from the first and second radial planes.       

     In the second embodiment, the directional control valve for fluid may have the following features:
         the first and second I/O ports and the administering port are substantially situated in the same midplane of the body, and the first link channel is situated in a first axial plane of the spool so that going between the first and second angular positions is obtained by turning the spool through a half-turn in the body; and   the first and third radial openings of the second link channel are situated in a second axial plane of the spool and the second radial opening is situated in a third axial plane of the spool that is angularly offset by about 90° relative to the second axial plane so that going between the first and third positions and going between the second and third positions is obtained by turning the spool through respective quarter-turns in the body.       

     In the third embodiment, the directional control valve for fluid may have all of the following features:
         the axes of the first and third radial openings of the first link channel and the first I/O port lie in a first radial plane;   the axes of the first, second and third radial openings of the second link channel, and the second I/O port lie in a second radial plane; and   the axis of the second radial opening of the first link channel and the administering port lie in a third radial plane distinct from the first and second radial planes.       

     In advantageous manner, the directional control valve further comprises an annular seal provided between the spool and the body, the annular seal having a solid portion through which orifices pass that are designed to be in register with the first radial opening, the second radial opening, and the third radial opening of said first link channel, with the first radial opening, the second radial opening, and the third radial opening of the second link channel, and with the first radial opening and the second radial opening of the third link channel, the solid portion being arranged to provide selective sealing between the link channels. 
     The invention also provides in-situ making-up and administering apparatus for making up in situ and for administering a solution obtained by mixing two ingredients coming from first and second reservoirs, the in-situ making-up and administering apparatus including a directional control valve for fluid, the valve comprising a body and a spool mounted to move in rotation in the body, motor-drive means for driving the spool, and a fluid-flow circuit element arranged to interconnect the first and second I/O ports, said apparatus being characterized in that it includes a directional control valve for fluid as defined above, motor-drive means for driving the spool, a fluid-flow circuit element arranged to interconnect said first and second I/O ports and the first reservoir, and a feed pump connected to the fluid-flow circuit element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention can be better understood and other advantages appear on reading the following detailed description of embodiments given by way of non-limiting example and with reference to the accompanying drawings, in which: 
         FIG. 1  is an exploded perspective view of a first embodiment of the directional control valve for fluid of the invention; 
         FIGS. 2 and 3  are respectively a section view and a front view of the  FIG. 1  valve of in a “transfer” first position; 
         FIGS. 4 and 5  are views similar to  FIGS. 2 and 3  and showing a “making-up” second position of the  FIG. 1  valve; 
         FIGS. 6 and 7  are views similar to  FIGS. 2 and 3  and showing an “administering” third position of the  FIG. 1  valve, in which position administering is performed from the first reservoir; 
         FIGS. 8 and 9  are section views of respective ones of two embodiments of in situ making-up and administering apparatus provided with the first embodiment of the valve of the invention; 
         FIG. 10  is a diagrammatic view of a second embodiment of the valve of the invention; 
         FIGS. 11 to 13  are diagrammatic views of the  FIG. 10  valve respectively in first, second, and third positions, similar to the above-mentioned positions, with administration being performed from the second reservoir; 
         FIG. 14  is a diagrammatic view of the valve of  FIGS. 11 to 13  shown in a third position equivalent to the position of  FIG. 13 , with administration being performed from the second reservoir; 
         FIG. 15  is a diagrammatic view similar to  FIG. 10  and showing a third embodiment of the valve of the invention; and 
         FIGS. 16 to 18  are diagrammatic views of the  FIG. 15  valve that are similar to  FIGS. 11 to 13 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The directional control valve for fluid and the in situ making-up and administering apparatus of the invention may be used for mixing a liquid first ingredient with a second ingredient of any type (concentrate, lyophilisate, powder, etc.). The solution as made up in situ may be administered by any suitable technique. In non-limiting manner, the following description relates to a valve that can be incorporated in apparatus for mixing pharmaceutical ingredients and for administering the resulting made-up solution by injection. 
     With reference to  FIGS. 8 and 9 , the mixing and administering apparatus  1   a  includes a directional control valve  10   a , an injection needle  11  (shown in  FIG. 8  only), motor-drive means  12 , a fluid-flow circuit element  13 , and a feed pump  14 . 
     With reference, in particular, to  FIGS. 1 to 7 , a first embodiment of the directional control valve  10   a  of the invention comprises a body  2 , a spool  3   a , and an annular seal  4  provided between the body  2  and the spool  3   a.    
     The body  2  is tubular in overall shape and defines a cylindrical chamber  20  opening out axially on either side of the body  2 . The body  2  is provided with radial first and second inlet/outlet (I/O) ports  21 ,  22  and with a radial administering port  23 , these ports extending radially from the chamber  20  and being disposed in the same midplane P 1  of the body  2 . The first and second I/O ports  21 ,  22  are diametrically opposite from the administering port  23 . The axis of the first I/O port  21  is situated in a first radial plane R 1 , the axis of the second I/O port  22  is situated in a second radial plane R 2  that is distinct from the first radial plan R 1 , and the axis of the administering port  23  is situated in a third radial plane R 3  provided between the first and second radial planes R 1 , R 2 . The body  2  is provided with an angular and axial abutment  24  that has a function that is specified below. In addition, the chamber  20  is provided with an internal shoulder  25  that has a function that is also specified below. The first and second I/O ports  21 ,  22  are designed to be connected to the feed pump  14  and to a first reservoir  100  via the fluid-flow circuit element  13 . In this embodiment, the feed pump  14  is provided between the first reservoir  100  and the first I/O port  21 . The administering port  23  is adapted to allow the made-up solution to exit and is suitable, for example, for receiving an injection needle  11  in interfitting manner for administering the solution by injection. 
     The spool  3   a  is cylindrical in overall shape and carries the annular seal  4  that is tubular in overall shape. For example, the annular seal  4  may be made of elastomer. In the example shown, the annular seal  4  is secured to the spool  3   a  over which it may be overmolded. The outside diameter of the annular seal  4  is substantially similar to the inside diameter of the chamber  20 . Thus, the spool  3   a  carrying the annular seal  4  can be received in the chamber  20 , the annular seal  4  providing the sealing between the spool  3   a  and the body  2 . The spool  3   a  is provided with axial third and fourth I/O ports  31 ,  32  provided at the same axial end of the spool  3   a , each port being provided with a respective transfer needle  36 ,  37 . In the example shown, each of the third and fourth I/O ports  31 ,  32  is provided with a respective transfer needle  36 ,  37  designed to perforate the stopper of a second reservoir  200 , e.g. a reservoir of the bottle type. The transfer needles  36 ,  37  of the third and fourth I/O ports  31 ,  32  are preferably of different lengths in order to facilitate the blending. The spool  3   a  is provided with link channels  5   a ,  6   a ,  7   a  that pass through it and that are connected to the third and fourth I/O ports  31 ,  32 . The link channels  5   a ,  6   a ,  7   a  comprise a first link channel  5   a , a second link channel  6   a , and a third link channel  7   a  that are independent from one another. For example, these link channels  5   a ,  6   a ,  7   a  may be of substantially circular cross-section. 
     With reference, in particular, to  FIGS. 2 and 4 , the first link channel  5   a  is in the shape of an upside down T having the end of its central trunk opening out axially at an axial third I/O port  31  and having its branches passing radially through the spool  3   a  and opening out at a first radial opening  51   a  and at a second radial opening  52   a  provided at the first radial plane R 1  containing the first I/O port  21 . 
     With reference, in particular, to  FIGS. 2 and 4 , the second link channel  6   a  is in the shape of an upside-down L having its long bar opening out axially at a fourth I/O port  32  and having its short bar opening out radially at a first radial opening  61   a  having its axis substantially coinciding with the second radial plane R 2  containing the second I/O port  22 . 
     The first and second link channels  5   a ,  6   a  are situated in the same first axial plane A 1  of the spool  3   a . The central trunk of the first link channel  5   a  and the second link channel  6   a  are disposed on either side of the axis M of the spool  3   a.    
     With reference, in particular, to  FIG. 6 , the third link channel  7   a  is inclined and passes laterally through the spool  3   a  while opening out at a first radial opening  71   a  having its axis substantially coinciding with the first radial plane  71  containing the axis of the first I/O port  21  and at a second radial end  72   a  having its axis substantially coinciding with the third radial plane R 3  containing the axis of the administering port  23 , the first and second radial openings  71   a ,  72   a  being diametrically opposite. The axis of the third link channel  7   a  is situated in a second axial plane A 2  of the spool  3   a . In the example shown, the second axial plane A 2  of the spool  3   a  is offset from the first axial plane A 1  of the spool  3   a  by an angle of about 90°. The third link channel  7   a  passes across the axis M of the spool  3   a  above the branches of the first link channel  5   a . In addition to this particular positioning of the third link channel  7   a  relative to the first and second link channels  5   a ,  6   a , the dimensions of the link channels  5   a ,  6   a ,  7   a  are designed so that there is no interference between the first or second link channels  5   a ,  6   a  and the third link channel  7   a.    
     In a variant embodiment (not shown), the third link channel may be designed so that its first end opens out in a third radial plane that coincides with the second radial plane containing the second I/O port. 
     In register with the first and second radial openings  51   a ,  52   a ,  71   a ,  72   a  of the first and third link channels  5   a ,  7   a , and in register with the first radial opening  61   a  of the second link channel  6 , the annular seal  4  is provided with through transfer orifices  40 - 44  allowing fluid to pass through them. The transfer orifices  40 - 44  thus include first and second transfer orifices  40 ,  41  that are diametrically opposite and that have their axes designed to be in the first radial plane R 1  and in register with respective ones of the axes of the first and second radial openings  51   a ,  52   a  of the first link channel  5   a . The first and second transfer orifices  40 ,  41  are thus designed with their axes in the first axial plane A 1 . The transfer orifices  40 - 44  also include a third transfer orifice  42  provided between the first and second transfer orifices  40 ,  41  with an axis in the first radial plane R 1 , in the second axial plane A 2  and in register with the first radial opening  71   a  of the third link channel  7   a . In addition, the link channels  40 - 44  include a fourth transfer orifice  43  having its axis designed to be in the second radial plane R 2  and in the second axial plane A 2 , in register with the second radial opening  72   a  of the third link channel  7   a . Finally, the link channels  40 - 44  include a fifth transfer orifice  44  having its axis designed to be in the second radial plane R 2  and in the first axial plane A 1 , in register with the first radial opening  61   a  of the second link channel  6   a . Each transfer orifice  40 - 44  is surrounded by an annular lip  45  that reinforces the sealing between the annular seal  4  and the body  2 . In addition, around its periphery, the annular seal  4  is provided with intermediate annular lips  46  making it possible to isolate the first, second, and third radial planes R 1 , R 2 , R 3  from one another. The annular seal  4  is also provided with two end annular lips  47  provided respectively beyond the first radial plane R 1  and beyond the second radial plane R 2  relative to the third radial plane R 3  and making it possible to isolate the first and second radial planes R 1 , R 2  from the outside. The intermediate annular lips  46  may be interconnected or be connected to the end annular lips  47  via crosspieces  48  (visible in  FIG. 7 ) preventing any annular flow of fluid, reinforcing the sealing of the valve  10   a  and making it possible to reduce the dead volume. 
     The spool  3   a  is blocked axially in the chamber  20  by the internal shoulder  25  in a first axial direction and by the angular and axial abutment  24  in a second axial direction. The spool  3   a  has an external lateral rib  35  (visible in  FIG. 1 ) designed to co-operate with the annular seal  4  to reinforce preventing the annular seal  4  from moving in rotation relative to the spool  3   a . The spool  3   a  is also provided with two shoulders  38  of diameter greater than the inside diameter of the annular seal  4  so as to block the annular seal  4  axially relative to the spool  3   a.    
     The spool  3   a  is provided with a radial lug  33  designed to co-operate with the angular and axial abutment  24  of the body  2  to limit the rotation of the spool  3   a  relative to the body  2 . 
     The spool  3   a  is coupled to motor-drive means  12  of standard type adapted to cause the spool  3   a  and the annular seal  4  to pivot angularly relative to the body  2  into predetermined angular positions. The mechanical coupling between the spool  3   a  and the motor-drive means  12  is of known type and is designed to make coupling and decoupling easy. 
     The fluid-flow circuit element  13  makes it possible to interconnect the first and second I/O ports  21 ,  22 . 
     With reference, in particular, to  FIG. 9 , the fluid-flow circuit element  13  may include a fluid-flow duct  131  having its ends connected to the first and second I/O ports  21 ,  22 , which duct is provided with first connection means  136  enabling it to be connected to the first reservoir  100 , and with second connection means  140  enabling it to be connected to a feed pump  14  disposed between the first reservoir  100  and the first I/O port  21 . In a variant embodiment (not shown), the feed pump is disposed between the first reservoir and the second I/O port. 
     With reference to  FIG. 9 , the body  2  may be extended laterally so that the first I/O port  21  is separated from the chamber  20  by a tube portion  133  provided with second connection means  140  enabling it to be connected to a feed pump  14  and with first connection means  136  provided at the first I/O port  21  and enabling it to be connected to the first reservoir  100 . In addition, the fluid-flow circuit element  13  includes a fluid-flow duct  131  having its ends connected to the first and second I/O ports  21 ,  22 . 
     The feed pump  14  is of any type adapted to cause the contained fluid to flow between the first reservoir  100  and the second reservoir  200  and then from the first or second reservoir  100 ,  200  to the administering port  23 . 
     In order to be used, the mixing and administering apparatus  1   a  is provided with a first reservoir  100  containing a liquid first ingredient and with a second reservoir  200  containing a second ingredient, e.g. in powder form. The first reservoir  100  is connected to the valve  10  between the first and second I/O ports  21 ,  22 . The second reservoir  200  is connected to the valve  10   a  between the third and fourth I/O ports  31 ,  32 . 
     In order to perform the making-up and the administering by means of the valve  10   a , the procedure is as described below. 
     With reference to  FIGS. 2 and 3 , the spool  3   a  is placed in a “transfer” first angular position relative to the body  2 , in which position the first axial plane A 1  of the spool  3   a  and the first midplane P 1  of the body  2  substantially coincide. Thus, the first radial opening  51   a  of the first link channel  5   a  is in register with the first I/O port  21 , the second radial opening  52   a  of the first link channel  5   a  being closed off by the wall of the chamber  20 . The feed pump  14  is caused to transfer liquid from the first reservoir  100  to the second reservoir  200  containing the second ingredient as indicated by arrows S 0 . The liquid contained in the first reservoir  100  passes through the first I/O port  21 , through the first transfer orifice  40  of the annular seal  4 , and through the first radial opening  51   a  of the first link channel  5   a , and flows through the first link channel  5   a  and then through the axial opening of the first link channel  5   a  and through the third I/O port  31  and into the second reservoir  200 . In this first angular position, the first radial opening  61   a  of the second link channel  6   a  and the administering port  23  are closed off by the wall of the chamber  20 . 
     With reference to  FIGS. 4 and 5 , once the liquid has been transferred to the second reservoir  200 , the made-up solution is blended so as to obtain a homogeneous mixture. This blending is performed by causing the mixture to flow from the second reservoir  200  and back to the second reservoir  200 . For this purpose, the spool  3   a  is pivoted through 180°, so as to place the spool  3   a  in a second angular position relative to the body  2 . This second position is referred to as the “making-up” position. The second angular position is defined by the radial lug  33  of the spool  3   a  in contact with the angular and axial abutment  24  of the body  2 . In this second angular position, the first axial plane A 1  of the spool  3   a  and the midplane P 1  of the body  2  substantially coincide but in a configuration that is axially symmetrical relative to the preceding configuration. Thus, in this second angular position, the second radial opening  52   a  of the first link channel  5   a  is in register with the first I/O port  21 , the first radial opening  51   a  of the first link channel  5   a  being closed off by the wall of the chamber  20 . In addition, the first radial opening  61   a  of the second link channel  6   a  is in register with the second I/O port  22 . In this second angular position, the administering port  23  is closed off by the wall of the chamber  20 . The feed pump  14  is caused to transfer the liquid between the third and fourth I/O ports  31 ,  32  of the spool  3   a . This flow of fluid may be caused in a first flow direction, indicated by arrows S 1 , firstly going through the fourth I/O port  32 , and then through the second link channel  6   a , through the first radial opening  61   a  of the second link channel  6   a , through the fifth transfer orifice  44  of the annular seal  4 , through the second I/O port  22 , through the fluid-flow circuit element  13 , through the first I/O port  21 , through the second transfer orifice  41  of the annular seal  4 , through the second radial opening  52   a  of the first link channel  5   a , through the first link channel  5   a , and then through the third I/O port  31 . The flow of fluid may also be caused in a second flow direction, indicated by arrows S 2 , firstly going through the third I/O port  31 , and then through the first link channel  5   a , through the second radial opening  52   a , through the second transfer orifice  41  of the annular seal  4 , through the first I/O port  21 , through the fluid-flow circuit element  13 , through the second I/O port  22 , through the fifth orifice  44  of the annular seal  4 , through the first radial opening  61   a  of the second link channel  6   a , through the second link channel  6   a , and then through the fourth I/O port  32 . This flow of fluid makes it possible to blend the mixture of the first and second ingredients and to obtain a homogeneous solution. 
     Once the homogeneous solution is obtained, in-situ in the reservoir  200 , the spool  3   a  is pivoted into the “transfer” first angular position of  FIGS. 2 and 3 , by pivoting, in the example shown, through 180° anticlockwise as seen from above. The feed pump  14  is caused to transfer the solution contained in the second reservoir  200  to the first reservoir  100  in the direction opposite to the direction indicated by arrows S 0  in  FIGS. 2 and 3 . 
     With reference to  FIGS. 6 and 7 , once the solution is contained in the first reservoir  100 , the solution can be administered. For this purpose, the spool  3   a  is pivoted through 90° (through 90° clockwise in the example shown) so as to place the spool  3   a  in a third angular position relative to the body  2 . This “administering” third angular position is angularly intermediate between the first and second angular positions. In this third position, the second axial plane A 2  of the spool  3   a  and the midplane P 1  of the body  2  substantially coincide. In the embodiment shown, in this third angular position, the first radial opening  71   a  of the third link channel  7   a  is in register with the first I/O port  21 , the second radial opening  72   a  of the third link channel  7   a  is in register with the administering port  23 , and the second radial opening  52   a  of the first link channel  5   a  and the radial opening  61   a  of the second link channel  6   a  are closed off by the wall of the chamber  20 . Thus, the first I/O port  21  is connected to the administering port  23 . The feed pump  14  is caused to transfer the liquid from the first reservoir  100  to the administering port  23  as indicated by arrows S 3 , via the first I/O port  21 , so that the solution can be injected by the injection needle  11 . Thus, the solution passes through the first I/O port  21 , through the third transfer orifice  42  of the annular seal  4 , through the third link channel  7   a , through the fourth transfer orifice  43  of the annular seal  4 , and then through the administering port  23 . 
     In another embodiment (not shown), the spool and the seal are formed integrally in one piece. In yet another embodiment (not shown), the seal is stationary relative to the body. 
       FIGS. 10 to 13  show a second embodiment of the directional control valve  10   b  of the invention having a body  2  similar to the body in the preceding embodiment and a spool  3   b  as described below. 
     The spool  3   b  is provided with third and fourth I/O ports  31 ,  32  similar to those of the preceding spool  3   a  from which it differs by its link channels  5   b ,  6   b  comprising a first link channel  5   b  and a second link channel  6   b  that are independent from each other. To facilitate understanding of  FIGS. 10 to 13 , the first link channel  5   b  is shown in double lines, and the second link channel  6   b  is shown as a single line. 
     The first link channel  5   b  is in the shape of an upside-down L provided with a plurality of short bars that are offset angularly and axially from one another. The central trunk of the first link channel  5   b  opens out axially at a third I/O port  31 . A first short bar of the first link channel  5   b  opens out radially at a first radial opening  51   b , a second bar of the first link channel  5   b  opens out radially at a second radial opening  52   b  and a third bar of the first link channel  5   b  opens out radially at a third radial opening  53   b . The first link channel  5   b  is situated in the same first axial plane A 1  of the spool  3   b . The second radial opening  52   b  and the third radial opening  53   b  are distributed on either side of the central trunk, their axes lying in a first radial plane R 1  of the spool  3   b  that contains the axis of the first I/O port  21 . The axis of the first radial opening  51   b  lies in a third radial plane R 3  of the spool  3   b  that is provided between the first radial plane R 1  and the third I/O port  31  and that contains the axis of the administering port  23 . The first link channel  5   b  is also provided with a first check valve  54  provided between the junction at which the central trunk meets the first radial opening  51   b  and the third I/O port  31  so as to prevent any flow of fluid from one of the short bars to the third I/O port  31 . 
     The second link channel  6   b  is in the shape of a T provided with a plurality of radial branches and having the end of its central trunk opening out axially at an axial fourth I/O port  32 . A first radial branch opens out at a first radial opening  61   b , a second radial branch opens out at a second radial opening  62   b , and a third radial branch opens out at a third radial opening  63   b . The axes of the first, second, and third radial openings  61   b ,  62   b ,  63   b  lie in a second radial plane R 2  provided beyond the third radial plane R 3  relative to the first radial plane R 1  and containing the axis of the second I/O port  22 . In addition, the axes of the second and third radial openings  62   b ,  63   b  are diametrically opposite, distributed on either side of the central trunk and lying in the first axial plane A 1 , and the axis of the first radial opening  61   b  lies in a second axial plane A 2 . In the example shown, the second axial plane A 2  is offset by 90° relative to the first axial plane A 1  so that going between the first and second positions, and going between the second and third positions, are obtained by turning the spool through respective quarter-turns inside the body. 
     With reference to  FIGS. 11 to 14 , the mixing and administering apparatus  1   b  is substantially similar to the preceding apparatus. It differs in that the feed pump  14  is provided between the first reservoir  100  and the second I/O port  22 . In addition, the first reservoir  100  is coupled to a second check valve  101  to prevent any flow of fluid towards the first reservoir  100 . 
     In order to perform the making-up and the administering by means of the valve  10   b , the procedure is as described below. 
     With reference to  FIG. 11 , the spool  3   b  is placed in a “transfer” first angular position relative to the body  2 , in which position the second axial plane A 2  of the spool  3   b  and the first midplane P 1  of the body  2  substantially coincide. Thus, the first radial opening  61   b  of the second link channel  6   b  is in register with the second I/O port  22 , the second and third radial openings  62   b ,  63   b  of the second link channel  6   b  being closed off by the wall of the chamber  20 . The feed pump  14  is caused to transfer liquid from the first reservoir  100  to the second reservoir  200  (not shown in this figure) containing the second ingredient as indicated by arrows S 0 . In this first angular position, the first, second, and third radial openings  51   b ,  52   b ,  53   b  of the first link channel  5   b  and the administering port  23  are closed off by the wall of the chamber  20 . 
     With reference to  FIG. 12 , once the liquid has been transferred to the second reservoir, the solution is blended. For this purpose, the spool  3   b  is pivoted through 90° (anticlockwise as seen from above in the example shown) so as to place the spool  3   b  in a “making-up” second angular position relative to the body  2 . Thus, in this second angular position, the first radial plane A 1  of the spool  3   b  and the midplane P 1  of the body  2  substantially coincide, and the second opening  52   b  of the first link channel  5   b  is in register with the first I/O port  21 , the first and third radial openings  51   b ,  53   b  of the first link channel  5   b  being closed off by the wall of the chamber  20 . In addition, the second radial opening  62   b  of the second link channel  6   b  is in register with the second I/O port  22 , and the first and third radial openings  61   b ,  63   b  of the second link channel  6   b  and the administering port  23  are closed off by the wall of the chamber  20 . The feed pump  14  is caused to transfer the liquid between the fourth and third I/O ports  32 ,  31  of the spool  3   b . This flow of fluid is caused in the first flow direction, as indicated by arrows S 1 . Optionally, during this transfer, the second check valve  101  prevents any return of fluid towards the first reservoir  100 . 
     Once the homogeneous solution has been obtained, in situ in the reservoir  200 , it is possible to administer it. With reference to  FIG. 13 , the spool  3   b  is pivoted through 180° so as to place the spool  3   b  in an “administering” third angular position relative to the body  2 . This third angular position is substantially symmetrical axially to the first angular position. In this third angular position, the first axial plane A 1  of the spool  3   b  and the midplane P 1  of the body  2  substantially coincide, and the third radial opening  53   b  of the first link channel  5   b  is in register with the first I/O port  21 , the first radial opening  51   b , of the first link channel  5   b  is in register with the administering port  23 , and the second radial opening  52   b  of the first link channel  5   b  is closed off by the wall of the chamber  20 . In addition, the third radial opening  63   b  of the second link channel  6   b  is in register with the second I/O port  22 , and the first and second radial openings  61   b ,  62   b  of the second link channel  6   b  are closed off by the wall of the chamber  20 . The feed pump  14  is caused to transfer the liquid from the second reservoir to the administering port  23  as indicated by arrows S 3 . During administering, the first check valve  54  prevents any return of fluid towards the second reservoir via the second channel  5   b . Administering is thus performed from the second reservoir. 
     In a variant embodiment shown in  FIG. 14 , in order to administer the solution from the first reservoir  100 , before administering, the solution is transferred from the second reservoir to the first reservoir. For this purpose, the spool  3   b  is pivoted from the second position to the first angular position of  FIG. 12  by pivoting the spool  3   b  through 90°, clockwise as seen from above in the example shown. The feed pump  14  is caused to transfer the solution contained in the second reservoir to the first reservoir  100  in the flow direction indicated by arrows S 4  that point in the opposite direction to the direction indicated by arrows S 0  in  FIG. 12 . In order to achieve such a mode of operation, the mixing and administering apparatus  1   b  does not have any second check valve  101 . Then, in order to go from this position to the above-described third position, the spool  3   b  is pivoted through 90°, clockwise as seen from above in the example shown, and the solution contained in the first reservoir  100  is administered. 
       FIGS. 15 to 18  show a third embodiment of the directional control valve  10   c  of the invention having a body  2  similar to the body in the preceding embodiment and a spool  3   c  as described below. 
     The spool  3   c  is provided with third and fourth I/O ports  31 ,  32  similar to those of the preceding spools  3   a ,  3   b  from which it differs by its link channels  5   c ,  6   c  comprising a first link channel  5   c  and a second link channel  6   c  that are independent from each other. To facilitate understanding of  FIGS. 15 to 18 , the first link channel  5   c  is shown in double lines, and the second link channel  6   c  is shown as a single line. 
     The first link channel  5   c  is in the shape of an upside-down L provided with a plurality of short bars that are offset angularly and axially from one another. The central trunk of the first link channel  5   c  opens out axially at a third I/O port  31 . A first short bar of the first link channel  5   c  opens out radially at a first radial opening  51   c , a second bar of the first link channel  5   c  opens out radially at a second radial opening  52   c  and a third bar of the first link channel  5   c  opens out radially at a third radial opening  53   c . The first link channel  5   c  is situated in the same first axial plane A 1  of the spool  3   c.    
     The axes of the second and third radial openings  52   c ,  53   c  lie in a first radial plane R 1  of the spool  3   c  that contains the axis of the first I/O port  21 . The axes of the second and third radial openings  52   c ,  53   c  are also angularly offset from each other; in the example shown, they are offset by 90°. The axis of the first radial opening  51   c  of the spool  3   c  lies in a third radial plane R 3  of the spool  3   c  that contains the axis of the administering port  23 , that is situated between the first radial plane R 1  and the third I/O port  31 . The axes of the first and third radial openings  51   c ,  53   c  lie in a first axial plane A 1  of the spool  3   c . The first link channel  5   c  is also provided with a first check valve  54  provided between the junction at which the central trunk meets the first radial opening  51   c  and the third I/O port  31  so as to prevent any flow of fluid from one of the short bars to the third I/O port  31 . 
     The second link channel  6   c  is in the shape of a T provided with a plurality of radial branches and having the end of its central trunk opening out axially at an axial fourth I/O port  32 . A first radial branch opens out at a first radial opening  61   c , a second radial branch opens out at a second radial opening  62   c , and a third radial branch opens out at a third radial opening  63   c . The axes of the first, second, and third radial openings  61   c ,  62   c ,  63   c  lie in a second radial plane R 2  provided beyond the third radial plane R 3  relative to the first radial plane R 1  and containing the axis of the second I/O port  22 . In addition, the axes of the second and third radial openings  61   c ,  63   c  are diametrically opposite, distributed on either side of the central trunk and lying in the first axial plane A 1 , and the axis of the second radial opening  62   c  lies in a second axial plane A 2 . In the example shown, the second axial plane A 2  is offset by 90° relative to the first axial plane A 1  so that going between the first and second positions, and going between the second and third positions, are obtained by turning the spool through respective quarter-turns inside the body. 
     With reference to  FIGS. 16 to 18 , the mixing and administering apparatus  1   c  is substantially similar to the preceding apparatus. It differs therefrom by the configuration of the first and second link channels  5   c ,  6   c.    
     In order to perform the making-up and the administering by means of the valve  10   c , the procedure is as described below. 
     With reference to  FIG. 16 , the spool  3   c  is placed in a “transfer” first angular position relative to the body  2 , in which position the second axial plane A 1  of the spool  3   c  and the first midplane P 1  of the body  2  substantially coincide. Thus, the first radial opening  61   c  of the second link channel  6   c  is in register with the second I/O port  22 , the second and third radial openings  62   b ,  63   c  of the second link channel  6   c  being closed off by the wall of the chamber  20 . The feed pump  14  is caused to transfer liquid from the first reservoir  100  to the second reservoir  200  (not shown in this figure) containing the second ingredient as indicated by arrows S 0 . In this first angular position, the first, second, and third radial openings  51   c ,  52   c ,  53   c  of the first link channel  5   c  and the administering port  23  are closed off by the wall of the chamber  20 . 
     With reference to  FIG. 17 , once the liquid has been transferred to the second reservoir, the solution is blended. For this purpose, the spool  3   c  is pivoted through 90° (clockwise as seen from above in the example shown) so as to place the spool  3   c  in a “making-up” second angular position relative to the body  2 . In this second angular position, the second radial plane A 2  of the spool  3   c  and the midplane P 1  of the body  2  substantially coincide, and the second radial opening  52   c  of the first link channel  5   c  is in register with the first I/O port  21 , the first and third radial openings  51   c ,  53   c  of the first link channel  5   c  being closed off by the wall of the chamber  20 . In addition, the second radial opening  62   c  of the second link channel  6   c  is in register with the second I/O port  22 , and the first and third radial openings  61   c ,  63   c  of the second link channel  6   c  and the administering port  23  are closed off by the wall of the chamber  20 . The feed pump  14  is caused to transfer the liquid between the third and fourth I/O ports  31 ,  32  of the spool  3   b . This flow of fluid is caused in the first flow direction, as indicated by arrows S 1 . Optionally, during this transfer, the second check valve  101  prevents any return of fluid towards the first reservoir  100 . 
     Once the homogeneous solution has been obtained, in situ in the reservoir  200 , it is possible to administer it. With reference to  FIG. 18 , the spool  3   c  is pivoted through 90° (clockwise as seen from above in the example shown) so as to place the spool  3   c  in an “administering” third angular position relative to the body  2 . This third angular position is substantially symmetrical axially to the first angular position. In this third angular position, the first axial plane A 1  of the spool  3   c  and the midplane P 1  of the body  2  substantially coincide, and the third radial opening  53   c  of the first link channel  5   c  is in register with the first I/O port  21 , the first radial opening  51   c , of the first link channel  5   c  is in register with the administering port  23 , and the second radial opening  52   c  of the first link channel  5   c  is closed off by the wall of the chamber  20 . In addition, the third radial opening  63   c  of the second link channel  6   c  is in register with the second I/O port  22 , and the first and second radial openings  61   c ,  62   c  of the second link channel  6   c  are closed off by the wall of the chamber  20 . The feed pump  14  is caused to transfer the liquid from the second reservoir to the administering port  23  as indicated by arrows S 3 . During administering, the first check valve  54  prevents any return of fluid towards the second reservoir via the second channel  5   c . Administering is thus performed from the second reservoir. 
     As appears from the description, the mixing and administering apparatus  1   a ;  1   b ;  1   c  of the invention thus includes a disposable portion and a reusable portion. The motor-drive means  12  can easily be decoupled from the spool  3  so as to be used with another directional control valve  10   a ;  10   b ;  10   c.    
     The invention makes it possible to achieve the above-mentioned objectives. The directional control valve for fluid and the mixing and administering apparatus are simple to use. The external and internal fluid paths of the directional control valve are simplified. 
     Naturally, the present invention is in no way limited to the above description of one of its implementations, which can undergo modifications without going beyond the ambit of the invention. For example, it is possible to increase the number of stages of the directional control valve for fluid, and to provide additional link channels, e.g. for connecting to additional reservoirs.