FR2760655A1 - REAGENT INJECTION PUMP IN MATRAS AND INJECTION METHOD USING SUCH PUMP - Google Patents

Abstract

The invention concerns a pump for injecting (1) reagent into a plurality of flasks (M) to carry out chemical reactions. The invention is characterised in that it comprises a reagent injecting unit comprising: a pump body (100) provided with a suction duct (111) designed to be connected to a reservoir of reagents and with as many injection ducts (112, 113, 114) as the maximum number n of flasks (M) to be supplied, each injection duct being connected to a flask; a bellows (130) capable of being translated between an expanded position and a compressed position; and a dispenser (120) mounted movable inside the pump body and comprising a connecting duct (121a, 121b) for connecting the suction ducts and the injection ducts to said bellows.

Description

 The present invention relates to a pump for injecting reagent into a plurality of flasks for carrying out chemical reactions, and to a method for injecting reagent into n flasks using such a pump.

 The invention finds a particularly advantageous application in the field of laboratory chemistry for carrying out chemical reactions automatically in a plurality of flasks.

 The current trend is to carry out different chemical reactions or not in a plurality of flasks in parallel, almost simultaneously. For this, the laboratory technician must inject determined quantities of reagent into the different flasks at the prescribed injection speed, then optionally heat the flasks containing the reactant and the reagent to carry out the corresponding chemical reactions.

 The quantity of reagent injected into the flasks as well as its injection speed must be precise.

 Indeed, the quantity of reagent injected into the flask, and the speed at which this injection is made, are determining for the good conduct of the chemical reaction in the flask.

 There is already known a pump for injecting reagents into a flask which comprises a system of solenoid valves making it possible to open and close pipes for supplying reagents from a reservoir to said flask.

 This solenoid pump has the main drawback of being complex and bulky since it requires as many solenoid valves as there are flasks to be supplied and reagents to be injected into them.

 In addition, such a pump does not operate in a fairly precise manner due to the complexity of actuating the solenoid valves for their opening and closing.

 The present invention provides a new pump for injecting reagent into a plurality of flasks which makes it possible to automatically inject in a precise and controlled manner, at the prescribed speed, predetermined doses equal or different from one or more reagents in flasks.

 More particularly, the injection pump according to the invention comprises a unit for injecting a reagent comprising - a pump body provided with a suction duct intended to be connected to a reagent tank and therefore injection pipes that the maximum number n of flasks to be supplied, each injection pipe being able to be connected to the flasks, - a bellows which can be actuated in translation between an expanded position and a compressed position, and - a distributor mounted to move inside the pump body and comprising a connection duct capable of connecting said suction and injection ducts to said bellows, the movement of said distributor being synchronized with the movement of said bellows so that during expansion, said bellows is connected to the suction pipe of the pump body, then during a successive compression, said bellows is connected either to an injection pipe, or again to the pipe d aspiration.

 Thus, thanks to the synchronized system of the distributor and the bellows of the injection pump according to the invention, it is possible precisely to supply a plurality of flasks with different or equal doses of reagent at a determined speed, the unit of injection with minimal bulk.

According to an advantageous embodiment of the injection pump according to the invention, the distributor takes the form of substantially a sphere which is rotatably mounted about an axis X in a housing of corresponding shape provided in the body pump. Part of the distributor connection duct extends along its axis
X of rotation and has one end opening out of said distributor to be connected to said bellows, the other part of said connection conduit extending transversely to the axis X of rotation and having one end opening out of said distributor to be connected to the suction and injection pipes of the pump body.

 According to this embodiment described above, it is preferable that the suction and injection conduits of the pump body extend along radii of a circle whose center is located on the axis X of rotation of said distributor. The angle formed between two successive conduits can be constant and depends on the number of conduits provided in said pump body.

 According to a preferred embodiment of the injection pump according to the present invention, said bellows is actuated by means of a stepping drive motor. This stepping drive motor for actuating said bellows is calibrated so that it is able to compress the latter by a chosen volume corresponding to a multiple of a determined unit volume.

 The unit volume can advantageously be of the order of 0.5 ml.

 In addition, there is provided a position sensor of said bellows associated with said stepping drive motor.

 The use of a stepping drive motor makes it possible to control the quantities of reagent injected into the corresponding flasks and thereby control the speed of injection of the quantities of reagent into said flasks. This stepping motor also ensures the return to the compressed position of the bellows whatever its starting position.

 In the case where the distributor of the injection unit of the injection pump according to the invention is rotatably mounted inside the pump body, the latter is advantageously linked in rotation to an incrementing disc having on its periphery of the notches positioned at positions corresponding to those of the suction and injection conduits of the pump body, said incrementing disc being rotated by a drive motor, and cutting a beam from a position sensor of said distributor so that the distributor is positioned in a given position by rotating the incrementing disc until the notch corresponding to said given position is placed at the position sensor and lets the beam pass through it .

 Advantageously according to the invention, there is provided an automatic synchronized control system for the drive motors of the incrementing disc and of the bellows, as a function of the information given by the respective position sensors of the latter.

 According to another embodiment of the injection pump according to the invention, provision may be made for the distributor to be mounted in translation inside the pump body, and for its displacement to be carried out using a drive motor, a synchronized control system making it possible to synchronize the operation of this drive motor with that of the stepper drive motor of said bellows.

 The injection pump according to the present invention may comprise injection arms which extend perpendicular to the axes of said flasks, above the latter, and each provided at their end with an injection head which s 'fits in the opening of the flask considered. These injection arms are advantageously articulated to allow the introduction and removal of the flies below the injection heads. A flexible pipe can be provided for connecting the suction pipe of the pump body to a reagent tank, and a flexible pipe for connecting each injection pipe of the pump body to an outlet opening of the head. injection of each injection arm, each flexible connection pipe passing through the injection arm considered.

 According to one embodiment, the injection pump comprises a plurality of injection units for the injection of a plurality of reagents.

 In this case, each injection head of each injection arm has a plurality of outlet orifices each connected by a flexible pipe connecting to an injection pipe of the pump body of each injection unit.

 Such an arrangement makes it possible to eliminate any risk of pollution between the various suction and injection conduits and a system for rinsing said conduits is not necessary.

 The pump body of an injection unit of the injection pump according to the invention can advantageously be made of fluorinated polyvinylidene, and the bellows and the distributor can be made of polytetrafluoroethylene.

 In addition, the flexible connection pipes can also be made of polytetrafluoroethylene.

 Of course, it is possible to envisage other equivalent materials for the production of the various aforementioned components of the pump, these materials having to resist the attack of any reagent without polluting it.

The invention also proposes a method for injecting reagent into n flasks using the pump described above, which for each unit for injecting a reagent, comprises the following steps a) initialization of the unit of injection by connecting the distributor to the suction duct of the pump body and placing the bellows in the compressed position, b) suction of a quantity Vs of reagent in said bellows by bringing said bellows in the expanded position, the quantity Vs drawn of reagent being equal to the volume of the fully expanded bellows, c) displacement of the distributor to connect its connection duct to the first injection duct of the pump body connected to the corresponding flask, d) comparison of the chosen quantity VR of reagent to be injected into said flask , to the quantity Vs of reagent aspirated
d1) If VR is greater than or equal to Vs then displacement of the bellows to the compressed position to inject the quantity Vs sucked of reagent in said flask, then displacement of the distributor to connect its connection duct to the suction duct of the body of pump,
d2) If VR is equal to zero, displacement of the distributor to reconnect its connection duct to the suction duct of the pump body, then actuation of the bellows to its compressed position to reinject the total quantity Vs of reagent aspirated into the reagent tank,
d3) if VR is less than Vs, compression of the bellows of the volume VR so as to inject said quantity VR of reagent into the corresponding flask, then displacement of the distributor to connect its connection duct to the suction duct of the pump body, then compression of the bellows to its compressed position in order to re-inject the quantity of reagent remaining in said bellows in the reagent reservoir, e) repetition of steps b) to d) for the second injection conduit connected to the following flask and so on up to the nth injection pipe connected to the nth flask, f) repeating steps b) to e) for each of the n flasks until the n flasks contain the determined quantities of reagent, that is to say until for all flasks, the quantity VR is equal to zero.

 According to the aforementioned method, at each repetition of steps b) to d) for each flask, the amount of VR reagent to be injected into said flask is reduced by the quantity previously injected until it becomes equal to zero.

 According to the process according to the invention, the speed of injection of reagent into the flasks is controlled by the amount of reagent injected into the flasks at each step d).

According to a variant of the method according to the invention, step d2) is omitted and step b) begins with the verification whether the chosen quantity VK of reagent to be injected into said flask is zero or not,
If VR is equal to zero then the distributor remains in place with its connection duct connected to the suction duct of the pump body and the bellows is kept in the compressed position, during an interval of dead time corresponding to the time taken by the distributor to go back and forth between the suction pipe and an injection pipe of the pump body and the bellows to pass from the compressed position to the expanded position then again to the compressed position, then repeating steps b) to d), for the second injection pipe and so on to the nth injection pipe of the pump body,
If VR is different from zero then suction of a quantity Vs of reagent in said bellows by bringing said bellows in the expanded position, the quantity Vs drawn of reagent being equal to the volume of the fully expanded bellows.

 The description which follows with reference to the appended drawings, given by way of nonlimiting examples, will make it clear what the invention consists of and how it can be implemented.

 In the accompanying drawings - FIG. 1 is a diagrammatic side section view of an injection pump according to the invention, - FIG. 2 is a top view of an injection pump according to the invention, - Figure 3 is a partial schematic view in side section of an injection unit of an injection pump according to the invention, - Figure 4 is a schematic front view of the incrementing disc of a distributor an injection unit of a pump according to the invention, FIG. 5a is a sectional view along the plane AA of FIG. 5b which represents an injection unit of an injection pump according to the invention, - Figure 5b is a sectional view along the plane BB of Figure 5a, - Figures 6 to 11 show the injection unit of Figures 5b and 5a at different stages of the injection process according to the invention.

 In Figures 1 to 3, there is shown an embodiment of an injection pump 1 of reagent in a plurality of flasks M for the conduct of chemical reactions. This injection pump 1 comprises a reagent injection unit 100 mounted on a frame 4 secured to a base 2 which includes a pump body 110 provided with a suction duct intended to be connected to a reagent tank and as many injection pipes as the maximum number n of flasks to be supplied, each injection pipe being intended to be connected to a flask.

 As shown more particularly in FIG. 5b, according to the embodiment shown in FIGS. 1 to 3, the pump body 110 of the injection unit 100 comprises a suction pipe 111, and three injection pipes 112 , 113, 114 intended to be connected to three flasks.

The injection 112,113,114 and suction 111 pipes of the pump body 110 extend along the radii of a circle, the angle formed between two successive pipes being constant and here equal to approximately 60 degrees.

 The injection unit 100 also comprises, as shown in FIGS. 1, 3 and 5a, a bellows 130 actuable in translation by following an axis Y between an expanded position and a compressed position. The bellows 130 may have an expanded volume of the order of 4 milliliters or even 2 milliliters for example. Its actuation system comprises a stepping drive motor 131 which is connected to a screw 132 one end of which is connected to the bellows 130. This stepping drive motor 131 is calibrated so that it is capable of compress said bellows 130 by a selected volume corresponding to a multiple (here an integer multiple) of a determined unit volume, here of the order of 0.5 milliliters.

 As shown in Figures 1 and 3, there is also provided a position sensor 133 of said bellows 130 associated with the stepping drive motor 131 by means of a flag 134 which makes it possible to identify the position of the bellows and more particularly when said bellows is in the expanded position or in the compressed position.

 The injection unit 100 further comprises a distributor 120 mounted for displacement inside the pump body 110 and comprising a connection duct 121 a, 121 b suitable for connecting the suction 111 and injection ducts 112,113,114 of the pump body 110 to said bellows 130 (see FIG. 5b), the movement of said distributor 120 being synchronized with the movement of said bellows 130 so that during expansion, said bellows 130 is connected to the suction duct 111 then during successive compression, said bellows 130 is connected either to an injection duct 112,113,114, or again to the suction duct 111.

 Synchronized control of the bellows and the distributor will be described in more detail later.

 It will be noted in Figures 1, 3 and Sa, that according to the embodiment shown, the axis of the bellows 130 is parallel to the axis of said distributor 120, the connection between the bellows 130 and the distributor 120 being made by the through a conduit 115 provided in the pump body 110.

 Here, the distributor 120 is in the form of substantially a sphere which ends in a cylindrical part 120a extending along an axis X. This sphere is rotatably mounted around the axis X in a housing of corresponding shape provided in the pump body 110.

 A part 121a of the connection duct of the distributor 12 () extends along its axis X of rotation and has an end opening out of said distributor to be connected via the conduit 115 to the bellows 130.

 Thus, during the rotation of the distributor 120, this part 1 21a of its connection conduit always remains connected to the conduit 115 making the connection to the bellows 130.

 The other part 121 b of the connection duct of the distributor 120 extends transversely to the axis X of rotation of the latter, and here more particularly perpendicular to said part 121 a of the connection duct. This other part 121b of the connection conduit has one end opening out of said distributor to be connected to the suction conduit 111 or to one of the injection conduits 112, 113, of the pump body 110.

 I1 it should be noted that the injection conduits 112, 113, 114 and suction 111 of the pump body 110 extend along the radii of a circle whose center is located on the axis X of rotation of said distributor 120 .

 Part 121b of the distributor 120 connection duct has an axis which cuts the center of the circle in which the injection and suction ducts of the pump body are distributed. Therefore, during the rotation of the distributor 120, this part 121b of the connection pipe comes to face one end of the injection pipes or the suction pipe of the pump body.

 Thus, the distributor 120 makes it possible to successively connect each injection and suction pipe of the pump body to the pipe 115 opening into the bellows 130.

 The rotary movement of the distributor 120 inside the housing provided in the pump body 110 is achieved by means of an incrementing disc 122 more particularly shown in FIGS. 1, 3 and 4, said distributor being linked in rotation to said incrementing disc.

 As shown in FIG. 4, this incrementing disc 122 has notches 122a, 122b, 122c, 122d on its periphery, positioned at positions corresponding to those of the suction 111 and injection 112, 113, 114 ducts of the pump body 110 .

 The incrementing disc 122 is rotated about the axis X by means of a drive motor 123 here in direct current.

 This incrementing disc 122 cuts a beam of a position sensor 124 of said distributor 120. Thus, the positioning of the distributor 120 in a given position is carried out by rotationally driving the incrementing disc 122 around the axis X until that the notch 122a, 122b, 122c, 122d corresponding to the given position is placed at the level of the position sensor 124 in order to release the beam passing through it.

 The pump according to the invention shown in the figures, comprises an automatic synchronized control system for the drive motors 131, 123 of the bellows and of the incrementing disc, as a function of the information given by the respective position sensors of the latter.

 Of course, according to a variant not shown, it is conceivable that the distributor is mounted in translation inside the body and moved using a drive motor whose operation is synchronized using a automatic control system for the operation of the stepper drive motor.

 As shown more particularly in FIGS. 1 and 2, the injection pump 1 comprises injection arms 10, here three injection arms 10, which extend perpendicular to the axes Z of the flasks M, above these last, and each provided at their end with an injection head 1 1 intended to fit into the opening of said flasks. These injection arms 1 () are articulated to allow easy installation and removal of the flasks M below the injection heads of said injection arms.

 There is provided a flexible hose for connection (not shown) of the suction pipe of the pump body of an injection unit to a reagent tank, and as shown in FIG. 1, a flexible hose for connection 3 of each injection pipe of the pump body 11 () with an outlet orifice provided in the injection head 111 of an injection arm, each flexible connection pipe 3 passing through said injection arm 1 () considered.

 Thus, the first injection conduit 112 of the pump body 110 has at its outlet a flexible connection pipe which engages in the first injection arm up to the outlet orifice provided in the injection head of said arm injection, the second injection pipe 113 of the pump body 110 is connected at the outlet to a flexible connection pipe which passes through the second injection arm to the outlet orifice provided in the injection head positioned at its end and the third injection conduit 114 of the pump body 110 has at its outlet a flexible connection pipe which passes through the third injection arm to the outlet orifice provided in the injection head of the latter .

 In the pump according to the invention, there are as many injection conduits in the pump body of an injection unit as there are injection arms, which corresponds to a determined maximum number of flasks to feed. Here, there are three injection pipes per pump body which allow three different flasks to be supplied via three injection arms.

 If the pump body of the injection unit of the pump according to the invention has a number greater than three of injection pipes, an equivalent number of injection arms provided with injection heads is then provided. the connection of these conduits to flasks.

 I1 it should be noted that according to the embodiment shown in the figures, the injection pump 1 comprises an injection unit with a pump body provided with a suction pipe, for injecting a reagent into the matras.

 According to a variant not shown, the injection pump 1 according to the invention comprises a plurality of injection units 100 for the injection of a plurality of reagents into a plurality of flasks.

 According to a preferred embodiment, it comprises four injection units comprising four independent pump bodies each provided with a reagent suction pipe and three reagent injection pipes.

 When the pump comprises a plurality of injection units, each injection head of the injection arms comprises a corresponding plurality of outlet orifices each connected by a flexible hose to an injection pipe of the pump body in each injection unit.

 When four injection units are provided in the injection pump according to the invention, for the injection of four reagents into three flasks via three injection arms, these injection arms are provided with injection heads each provided with four outlet ports, each outlet port of each injection head being connected to an injection pipe of the pump body of each injection unit.

 The distributor 120, the bellows 130 of each injection unit and all of the flexible pipes for connection between the orifices of the injection heads of the injection arms and the outlets of the injection pipes of the pump body as well as the connection pipe between the suction pipe of the pump body and the reagent tank, are made of polytetrafluoroethylene called Teflon (registered trademark).

 The pump body 110 of an injection unit is advantageously made of fluorinated polyvinylidene and the injection arms 10 are made of polyvinyl chloride.

 The process for injecting reagent into a plurality of flasks using the injection pump according to the invention will now be described more particularly with reference to FIGS. 6 to 11.

 It should be noted that according to the embodiment shown in these figures, the number of flasks is equal to 3.

 Of course, one could imagine that the number n of flasks is greater than or less than 3.

 The first step of the method according to the invention is a step of initializing the injection unit or of each injection unit of the injection pump 1. At the end of this initialization step, in each injection unit, the distributor 120 is connected via its connection duct 121b to the suction duct 111 of the pump body 110 and the bellows 130 is in the compressed position (see FIG. 6).

 More particularly, the initial positioning of the dispenser is carried out as follows. The incrementing disk 1 22 performs a complete revolution during which the position of the notches 122a 122b, 122c, 122d is identified. Because all of these notches are located on a half circumference of the incrementing disc, thanks to the position sensor 124, the first notch which is located after the passage through the position sensor of the half circumference of the incrementing disc is located, which does not contains no notch and thus the position of all the following notches is identified.

 When this first notch 122a has been identified, the distributor 12 () is positioned so that its connection duct 121b as shown in FIG. 6 is connected to the suction duct l l l of the pump body.

 During this first initialization step, the bellows 130 is also brought into its compressed position. To do this, using the positioning sensor 133 associated with the flag 134, the bellows 130 are first of all brought into the expanded position and then, by means of the stepping drive motor 131, it is brought back ci in compressed position.

 The next stage of the process is a suction stage during which a quantity Vs of reagent is aspirated in the bellows 130 of each injection unit, by bringing the latter via the stepping drive motor. 131 in the expanded position, the quantity Vs aspirated of reagent being equal to the volume of the fully expanded bellows.

 During the next step shown more particularly in Figure 7, while said bellows 130 is in the expanded position, the associated distributor is moved, here by rotation via the DC drive motor 123, to connect its connection conduit 121b to the first injection conduit 112 of the pump body, this first injection conduit 112 being connected or not to a flask via an injection arm.

 In a following step, the automatic synchronization system of the distributor and of the associated bellows compares the chosen quantity VR of reagent to be injected into said flask with the quantity Vs of reagent aspirated.

 If the quantity VR chosen is greater than or equal to the quantity Vs aspirated inside the bellows, then the stepping drive motor 131 moves the bellows 130 to the compressed position to inject the quantity Vs aspirated of reagent into said flask.

 Subsequently, as shown in FIG. 8, while the bellows 130 is in the compressed position, the drive motor 123 moves the corresponding distributor 120 to bring it into a position where its connection duct 121b is connected to the duct d suction 11] of the pump body.

 If the quantity VR chosen to be injected into the corresponding flask is equal to zero (case where there is no flask connected to said corresponding injection duct or case where the prescribed quantity of reagent is already in said flask), then we moves the associated distributor 12 () to reconnect it to the suction duct, then the stepping drive motor 131 brings the bellows to its compressed position to reinject the total quantity Vs of reagent aspirated during the second step, in the reagent tank.

 injection pipe 112. This makes it possible, as will be described in more detail later, to calibrate the speeds of injection of reagent in the flasks on the maximum speed authorized by said pump, the modifications (possible decreases) of these speeds of injection being carried out by modifying the quantities of reagents injected into said flasks at each stage of compression of the corresponding bellows.

 Finally, if the quantity VR chosen to be injected into the corresponding flask is less than the quantity Vs of reagent aspirated, the bellows 120 is moved using the stepping drive motor 130, to compress it by the volume VR in order to d '' inject this quantity VR of reagent into the corresponding flask. Then, the associated distributor 120 is moved to connect it to the suction duct 111 and finally the bellows 130 is brought to its compressed position in order to reinject the quantity of reagent remaining in said bellows, in the reagent reservoir.

 Thus, as shown in FIG. 8, at the end of this step the bellows 130 of each injection unit is returned to the compressed position, emptied of any reagent, and the associated distributor 120 is again positioned with its connection conduit 121b connected to the suction pipe 111 of the pump body.

 During the aforementioned steps of said method, some of which are shown in FIGS. 6 to 8, the part 121a of the connection conduit of the distributor 120 of each injection unit remains of course connected via the conduit 115 provided in the body pump of said unit, to the associated bellows 130.

 Thereafter, according to the present method, the steps described above are repeated, for the other injection pipes 113, 114 of the corresponding pump body, connected or not to a flask, here for the second and third injection pipes 113 and 114 of the pump body 110 of each injection unit.

 In fact, as shown in FIG. 9 for an injection unit, after the step in FIG. 8, the quantity Vs of reagent is aspirated in said bellows, this quantity being equal to the total volume of the expanded bellows.

Then, the drive motor of the associated distributor moves the latter until its connection conduit 121b is connected to the injection conduit 113 of the pump body 110.

 At this stage, the quantity VR of the prescribed volume to be injected into the flask corresponding to the injection pipe 113 is again compared with the quantity Vs of reagent drawn into the bellows and if this quantity is greater than or equal to Vs, it is compressed the bellows to its compressed position to inject the quantity Vs inside this flask.

 Then, the distributor is brought back to the suction position with its connection duct 121b connected to the suction duct 111 of the pump body 110.

 If the prescribed quantity VR to be injected into the corresponding flask is equal to zero, said distributor 120 is returned directly to its previous position with its connection duct 121b connected to the suction duct 111 of the pump body 110 and the bellows is completely compressed 130 to reinject the aspirated quantity Vs into the reagent tank.

 Finally, if the prescribed quantity VR to be injected into the corresponding flask is less than that Vs drawn inside the bellows, the stepping drive motor 131 compresses volume VR said bellows in order to inject said quantity VR into the then move the distributor 120 to bring it back to the suction position with its connection duct 1 21b connected to the suction duct 111 of the pump body 110 and we finish completely compressing the bellows to reinject the remaining amount of reagent in the reagent tank.

 As already explained above, at the end of this step, shown in FIG. 10, the bellows 130 of said injection unit is in the compressed position and the distributor has returned to the initial position with its connection conduit 121b communicating with the suction duct 111.

 The same process steps are repeated for the last pipe or the next pipe, here the injection pipe 114 of the pump body of each injection unit as shown in FIG. 11. Before the step shown in FIG. 11 , of course, there is the step of sucking the reagent into the bellows of said injection unit, by expanding the bellows to the expanded position. Then follows the rotation stage (FIG. 11) of the associated distributor to bring its connection conduit i 21b opposite the injection conduit 114 of the pump body. Next, the comparison described above is carried out to inject the prescribed quantity of reagent into the flask corresponding to the injection pipe 114 before returning to the initial position with the compressed bellows and the distributor in the suction position with its connection pipe 121. b connected to the suction pipe 111 of the pump body.

 All of the steps, apart from the initialization step, are repeated as described above for the n matras here the three matras until these contain the quantities of reagent determined, that is to say until '' that for all flasks, the quantity VR of reagent to be injected is equal to zero.

 It is understood that, in accordance with the present invention, before each repetition of the suction and injection steps in the flask corresponding to a particular injection pipe, the quantity of reagent to be injected into this flask is reduced by the quantity previously injected until this amount becomes zero.

 It will be noted that according to the present method when the quantity of reagent to be injected into a flask becomes equal to zero, while the quantity of reagent to be injected into other flasks by other injection conduits is still not zero, the system is designed so that the process continues by repeating the same steps (in particular, aspiration of the reagent in the bellows), and during the injection step there is then a fictitious injection into said flask already filled (or absent) . Thus, the injection speed in all of the flasks connected to the pump bodies of the injection units remains constant.

 For example, if the injection pipe 113 is not connected to a flask or is connected to a flask already filled with reagent, then in order to be able to fill at the same speed the flasks connected to the injection pipes 112 and 114.1 the suction step for the injection pipe 11S takes place in the same way as for the other pipes 112, 114 but during the injection step in the injection pipe 1 1 3, the distributor will return directly to the suction duct 111 without the bellows having been emptied and the reagent drawn into the bellows by compression of the latter will be reinjected into the reagent reservoir. Thus, the injection speed in the three injection conduits and in particular in the injection conduits 112, 114 is constant.

 Advantageously, according to this method, the speed of injection of reagent in each flask is controlled by controlling the quantity of reagent injected into the latter at each stage of compression of the filled bellows.

 Indeed, if one wants to decrease the injection speed compared to the maximum injection speed, then it suffices that the stepping drive motor instead of completely compressing the bellows during a step of injection, compresses it only partially, then the remaining amount is reinjected into the reagent reservoir. Thus, additional suction and injection steps will be required to fill each flask with the prescribed quantity, which amounts to reducing the speed of injection of the total quantity of reagent in said flask.

 It should be noted that, advantageously according to the method according to the present invention, it is possible to choose to inject the reagent (s) at the same injection speed into the different flasks, or to individualize the injection speed for each flask by varying the amount of reagent injected into it at each stage of compression of the corresponding bellows.

 The injection pump according to the invention, which has several injection units and therefore several pump bodies, the injection pipes of which are connected to the orifices of the injection heads of the injection arms, operates in such a way that the operator whatever the reagent chosen for a given flask has the impression that all of its flasks are filled with different reagents practically simultaneously.

 The injection pump and the method according to the present invention have the following advantages.

 First of all, the pump is designed with a reagent injection unit and therefore there is no possible reagent mixture in the connection pipes between the different pump bodies and the orifices of the heads. injection leading into the flasks, which implies that there is no need to rinse the connecting pipes between the injection of one reagent and the injection of another reagent.

 The injection of different reagents into the flasks can then be easily done in a relatively short time by actuating the corresponding injection units.

 The step-by-step operation of the bellows drive motor of an injection unit makes it possible to control the injection speed and to respect the injection speed prescribed by the operator at the start of the reagent injection process in the flasks, as well as to return in a certain way to the compressed position of the bellows.

 According to the process according to the present invention, the fictitious steps of injecting reagent into the matras already filled or absent, makes it possible to standardize the speed of injection of reagent in all of the matras to be filled in the pump according to the invention.

 The automatic synchronization system makes it possible to inject fully automatically very precisely at a well-defined injection speed, the prescribed quantity of reagent in the flask.

 The present invention is in no way limited to the embodiments described and shown, but a person skilled in the art will know how to make any variant in accordance with his spirit.

 According to a variant not shown, each pump body of each injection unit of the pump according to the invention comprises several reagent suction pipes, each suction pipe being connected independently by a flexible pipe of connection to a given reagent tank.

 According to a variant of the process according to the invention, it is possible to envisage checking at the start of the aspiration step whether the quantity VR chosen to be injected into the corresponding flask is equal or not to zero.

 If this quantity VR is equal to zero then the distributor remains in place with its connection duct connected to the suction duct of the pump body and the bellows is kept in the compressed position, for an interval of dead time corresponding to the time taken by the distributor to go back and forth between the suction pipe and an injection pipe of the pump body, and to the bellows to go from the compressed position to the expanded position and then again to the compressed position. Thereafter, the suction step of said process is then repeated for the next injection pipe connected or not connected to a flask and so on to the nth injection pipe connected to the nth flask.

If this quantity VR is different from zero then we aspirate a quantity
Vs of reagent in said bellows, which corresponds to the volume of the fully expanded bellows. Then, the following steps of the method previously described are carried out.

 According to this variant, of course, during the injection step, the quantity VR chosen is no longer compared with the value zero.

Claims (25)

 1. Injection pump (1) of reagent in a plurality of flasks (M) for carrying out chemical reactions, characterized in that it comprises an injection unit (100) of a reagent comprising - a body of pump (100) provided with a suction pipe (111) intended to be connected to a reagent tank and as many injection pipes (112, 113, 114) as the maximum number n of flasks (M) to be supplied, each injection pipe (112, 113, 114) being able to be connected to a flask, - a bellows (130) actuatable in translation between an expanded position and a compressed position, and - a distributor (120) mounted moving inside the pump body (110) and comprising a connection conduit (121a, 121b) capable of connecting said suction (111) and injection (112, 113, 114) conduits to said bellows (130 ), the movement of said distributor (120) being synchronized with the movement of said bellows (130) so that during an exp ansion, said bellows (130) is connected to the suction pipe (111) of the pump body (110) then during a successive compression, said bellows (130) is connected either to an injection pipe (112, 113 , 114), or back to the suction duct (111).  2. Injection pump (1) according to claim 1, characterized in that the distributor (120) is in the form of substantially a sphere which is rotatably mounted about an axis X in a housing of corresponding shape provided in the pump body (110).  3. Injection pump (1) according to claim 2, characterized in that a part (121a) of the distributor connection pipe (120) extends along its axis X of rotation and has one end opening out at outside of said distributor (120) to be connected to said bellows (130), the other part (121b) of said connection duct extending transversely to the axis of rotation and having one end opening out of said distributor (120 ) to be connected to the suction (111) and injection (112, 113, 114) conduits of the pump body (110).  4. Injection pump (1) according to one of claims 2 or 3, characterized in that the suction (111) and injection (112, 113, 114) conduits of the pump body (110) s 'extend along radii of a circle whose center is located on the axis X of rotation of said distributor.  5. Injection pump (1) according to claim 4, characterized in that the angle formed between two successive conduits (111, 112, 113, 114) is constant and a function of the number of conduits provided in said pump body ( 110).  6. Injection pump (1) according to any one of claims 1 to 5, characterized in that said bellows (130) is actuated by means of a stepping drive motor (131).  7. Injection pump (1) according to claim 6, characterized in that the stepping drive motor (131) for actuating said bellows (130) is calibrated so that it is able to compress the latter of a selected volume corresponding to a multiple of a determined unit volume.  8. Injection pump (1) according to claim 7, characterized in that said unit volume is of the order of 0.5 ml.  9. Injection pump (1) according to one of claims 6 to 8, characterized in that there is provided a position sensor (133) of said bellows (130) associated with said stepping drive motor (131 ).  10. Injection pump (1) according to any one of claims 2 to 9, characterized in that the distributor (120) is linked in rotation to an incrementing disc (122) having on its periphery notches (122a, 122b , 122c, 122d) positioned at positions corresponding to those of the suction (111) and injection (112, 113, 114) conduits of the pump body (110), said incrementing disc (122) being rotated by a drive motor (123), and cutting a beam from a position sensor (124) of said distributor (120) so that the positioning of the distributor (120) in a given position is effected by driving the disc in rotation incrementer (122) until the notch corresponding to said given position is placed at the level of the position sensor (124) and lets the beam pass through it.  11. Injection pump (1) according to claim 10, in its dependence on claim 9, characterized in that there is provided an automatic synchronized control system of the drive motors (123, 131) of the incrementing disc ( 122) and the bellows (130), as a function of the information given by the respective position sensors (124, 133) of the latter.  12. Injection pump (1) according to one of claims 6 to 9 in its dependence on claim 1, characterized in that the distributor is mounted in translation inside the pump body, and is moved to the using a drive motor synchronized via an automatic piloting system to the stepping drive motor of said bellows.  13. Injection pump (1) according to any one of claims 1 to 12, characterized in that it comprises injection arms (10) which extend perpendicular to the axes (Z) of the flasks (M ), above the latter, and each provided at their end with an injection head (11) which fits into the opening of the flask (M) considered.  14. Injection pump (1) according to claim 13, characterized in that the injection arms (10) are articulated.  15. Injection pump (1) according to one of claims 13 or 14, characterized in that a flexible pipe is provided for connection of the suction pipe of the pump body (110) to a reagent tank, and a flexible hose for connection (3) of each injection pipe (112, 113, 114) of the pump body (110) to an outlet orifice of the injection head (11) of each injection arm, each flexible connection pipe (3) passing through the injection arm (11) considered.  16. Injection pump (1) according to claim 15, characterized in that the pump body (110) comprises a suction pipe (111) and three injection pipes (112, 113, 114) associated with three flask via three injection arms (10).  17. Injection pump (1) according to one of claims 1 to 16, characterized in that it comprises a plurality of injection units (10 ()) for the injection of a plurality of reagents.  18. Injection pump according to claim 17, in its dependence on one of claims 13 to 16, characterized in that each injection head (11) of each injection arm (10) comprises a plurality of outlet ports each connected by a flexible hose connecting to an injection pipe of the pump body of each injection unit.  19. Injection pump (1) according to claim 18, characterized in that it comprises four units for injecting four reagents into three flasks via three injection arms provided with injection heads each provided with four outlet orifices , each outlet of each injection head being connected to an injection pipe of the pump body of each injection unit.  20. Injection pump (1) according to one of claims 1 to 19, characterized in that the pump body (110) is made of fluorinated polyvinylidene, the bellows (130) and the distributor (120) are made of polytetrafluoroethylene.  21. Injection pump (1) according to one of claims 15 to 20, characterized in that the flexible connection pipes are made of polytetrafluoroethylene.  22. Method for injecting reagent into n flasks using the injection pump according to one of claims 1 to 21, characterized in that for each unit for injecting a reagent, it comprises the steps following a) initialization of the injection unit (100) by connecting the distributor (120) to the suction pipe (111) of the pump body (110) and by placing the bellows (130) in the compressed position, b) aspiration of a quantity Vs of reagent in said bellows (130) by bringing said bellows into the expanded position, the quantity Vs drawn of reagent being equal to the volume of the bellows (130) fully expanded, c) displacement of the distributor to connect its conduit connection (121b) to the first injection duct (112) of the pump body (110) connected to the corresponding flask, d) comparison of the chosen quantity VR of reagent to be injected into said flask, with the quantity Vs of reagent aspirated  d1) If VR is greater than or equal to Vs then displacement of the bellows (130) to the compressed position to inject the quantity Vs drawn of reagent in said flask, then displacement of the distributor (1 2 ()) to connect its conduit connection (121b) to the suction pipe (111) of the pump body (110),  d2) If VR is equal to zero, displacement of the distributor (12 ()) to reconnect its connection duct (121b) to the suction duct (111) of the pump body (110) then actuation of the bellows until its compressed position to reinject the total quantity Vs of reagent aspirated into the reagent reservoir,  d3) if VR is less than Vs, compression of the bellows (130) of the volume VR so as to inject said quantity VR of reagent into the corresponding flask then displacement of the distributor (120) to connect its connection duct (121b) to the suction duct (111) of the pump body (110), then compression of the bellows to its compressed position to re-inject the quantity of reagent remaining in said bellows (130) in the reagent reservoir, e) repeating steps b) to d) for the second injection conduit connected to the following flask and so on up to the nth injection pipe connected to the nth flask, f) repeating steps b) to e) for each of the n flasks until the n flasks contain the determined quantities of reagent, i.e. dirc until for all the flasks, the quantity VR is equal to zero.  23. The method as claimed in claim 22, characterized in that at each repetition of steps b) to d) for each flask, the amount of VR reagent to be injected into said flask is reduced by the amount previously injected until it becomes zero.  24. Method according to one of claims 22 or 23, characterized in that the speed of injection of reagent into the flasks is controlled by the amount of reagent injected into the flasks at each step d).  25. Method according to one of claims 22 to 24, characterized in that step d2) is deleted and step b) begins with the verification whether the chosen quantity VR of reagent to be injected into said flask is equal or not to zero,  - If VR is equal to zero then the distributor remains in place with its connection duct connected to the suction duct of the pump body and the bellows is kept in the compressed position, during an interval of dead time corresponding to the time taken by the distributor to go back and forth between the suction pipe and an injection pipe of the pump body and the bellows to pass from the compressed position to the expanded position then again to the compressed position, then repeating steps b) to d), for the second injection pipe and so on up to the nth injection pipe of the pump body,  - If VR is different from zero then aspiration of a quantity Vs of reagent in said bellows by bringing said bellows in the expanded position, the quantity Vs drawn of reagent being equal to the volume of the fully expanded bellows.