Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/02—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
  • F04B43/04—Pumps having electric drive
  • F04B43/043—Micropumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
  • F04B53/10—Valves; Arrangement of valves
  • F04B53/1037—Flap valves
  • F04B53/1047—Flap valves the valve being formed by one or more flexible elements
  • F04B53/106—Flap valves the valve being formed by one or more flexible elements the valve being a membrane
  • F04B53/1067—Flap valves the valve being formed by one or more flexible elements the valve being a membrane fixed at its whole periphery and with an opening at its centre

Definitions

• the invention relates to a fluidic device such as a micropump comprising at least a first wafer, a second wafer, an intermediate plate disposed between said first and second wafers, a pumping chamber delimited by said first wafer and said intermediate wafer and organs inlet and outlet control communicating with said pumping chamber, inlet and outlet conduits passing right through one of said first and second plates, said inlet control member being a non-return valve composed of '' a movable member and a membrane-shaped part connecting said movable member to the rest of said intermediate plate, interposed between the inlet duct and the pumping chamber and allowing, by its elasticity, the movement of said valve between a position closed and an open position, said movable member being traversed by an orifice, between the first and second ends, said valve being shaped so that, in said open position, the movable member does not prevent the flow of liquid from said orifice to said pumping chamber and the second end of the movable member being shaped to ensure, in said closed
• such a device constitutes a micropump for medical use which regularly delivers a controlled quantity of medicament.
• the manufacturing of these micropumps is based on micromachining technologies of silicon or any other material that can be machined by etching using photolithographic techniques.
• the micropump is controlled by varying the volume of the pumping chamber (alternating decreases and increases), for example by means of control by a piezoelectric actuator.
• European patent application 95904674.9 discloses such a self-priming micropump.
• the inlet valves described in this document cannot be made easily.
• European patent application 90 810272.6 describes a micropump comprising an inlet member, forming a non-return valve, which however does not ensure self-priming of the pump.
• the object of the present invention is to provide a fluidic device such as a micropump comprising an input control member making it possible to safely obtain the self-priming of said device, this member being able to be easily manufactured.
• this objective is achieved by the fact that the movable member is located over most of the thickness of said intermediate plate, that the membrane-shaped part is located near the other of the plates and that said orifice has a limited volume.
• the liquid inlet control member included in the device according to the present invention constitutes a non-return valve of the seat valve type.
• This non-return valve has a membrane-shaped part allowing, by its elasticity, the opening and closing of the valve and a movable member surrounding an orifice intended for the flow of liquid.
• the movable member also comprises at one of its ends means ensuring the tightness of this inlet valve in its closed position, that is to say that the movable member is in sealed contact support against the one of the plates adjacent to the valve, this plate forming the seat of the valve.
• the first end of the movable member adjacent to said shaped part diaphragm is provided with at least one stop element intended to limit the movement of said valve from the closed position to the open position, the free end of said stop element coming into contact with the plate located near the part in membrane form in said open position without said stop member preventing the flow of liquid from said orifice to said pumping chamber.
• Figure 2 is a view similar to that of Figure 1 concerning a second type of micropump, Figures 1 and 2 showing the liquid inlet control member in its closed position;
• FIG. 3 is an enlarged view of a detail of Figures 1 or 2, this detail concerning the area of the micropump comprising the liquid inlet control member or inlet valve;
• FIG. 4 shows partially and schematically, in bottom view in direction IV-IV, the inlet valve of Figure 3;
• FIG. 5 is a view similar to that of FIG. 3 showing an alternative embodiment of the non-return valve, in the closed position, this valve constituting the inlet control member of the micropump according to the present invention, and , - Figure 6 shows the area of the micropump as illustrated in Figure 3 provided with an alternative embodiment of the non-return valve for the entry of the liquid.
• the micropumps 10 and 100 comprise a base plate 12, preferably made of glass, traversed right through by two conduits 14, 16 respectively forming an inlet conduit and an outlet conduit for the micropump.
• An intermediate plate 18 surmounts the base plate 12, this intermediate plate preferably being made of silicon and connected to the base plate 12 by the technique, known per se, of anodic welding.
• the intermediate plate 18 is surmounted by an upper plate 20 or second plate, preferably made of glass, the intermediate plate and the second plate being interconnected by the same technique as the base plate 12 and the intermediate plate 18.
• the first plate 12 and the second plate 20 have a substantially equal thickness of the order of 1 mm while the intermediate plate also has a thickness which is also substantially constant but smaller, between 0.1 and 0.5 mm, preferably between 0 , 3 and 0.5 mm and advantageously of the order of 0.3 mm.
• a portion of the intermediate plate 18 constitutes a pumping membrane 22 of substantially circular shape and delimiting, with the upper face of the first plate 12, the pumping chamber 24.
• the pumping membrane 22 constitutes a movable wall controlled by an actuating device 26, 126.
• the inlet duct 14 is connected to the pumping chamber 24 by one or more inlet control members 28 which will be described in more detail below.
• the pumping chamber 24 is connected to a liquid outlet control member or outlet valve 30 which may be of structure similar to that described in the aforementioned European patent application 95 904674.9.
• the outlet valve 30 shown comprises the elements provided for in the above European patent application, namely an annular rib 32 placed opposite the outlet duct 16 and in sealing contact with the upper surface of the first plate 12 in the closed position of the outlet valve 30, a flexible membrane 34, and thin layers of silicon oxide 36 and 38 making it possible, respectively, to avoid adhesion between the annular rib 32 and the first plate 12, and, on the side of the membrane 34 opposite the first plate 12, to create a prestressing urging the top of the rib 32 against the first plate 12.
• the outlet valve 30 also comprises a limiting member 39 disposed at the level of the annular rib 32, on the face of the flexible membrane 34 opposite the first plate 12, this limiting member constituting a stop element coming to bear against the second plate 20 in the open position of the outlet valve 30 in order to limit the spacing of the annular rib 32 relative to the first plate 12.
• the inlet valve 28 consists of a movable member 40 surrounded by a membrane-shaped part 42.
• This membrane 42 is substantially circular with a diameter of the order of 3 mm, its thickness, preferably substantially constant, is between 10 and 50 ⁇ m, preferably of the order of 25 ⁇ m.
• the inlet valve or valves 28 constitute non-return valves, part of which abuts against one of the first and second plates, in the closed position of the valve.
• the movable member 40 surrounds an orifice 44 which passes through the movable member 40 from its first end 45, adjacent to the first wafer 12, towards its second end 46, adjacent to the second wafer 20.
• the movable member 40 preferably has an outer shape of revolution, for example a substantially cylindrical outer shape with circular section or, as illustrated in FIGS. 1 to 3, in the shape of a truncated cone, the widest part being directed to the first plate 12.
• the orifice 44 its volume constituting a connection space being added to the volume of the pumping chamber 24, it is necessary that it is minimum so as not to constitute too large a volume relative to the volume of the pumping chamber 24.
• This orifice 44 can have various shapes such as cylindrical, circular, square or other section, in frusto cone or in the shape of a pyramid. If the technique used to etch the silicon plate constituting the intermediate plate 18 makes it possible to produce an orifice 44 of small diameter, it is possible to produce an orifice 44 having a small section and substantially equal over the entire length of this orifice 44.
• the orifice 44 has a shape made up of two pyramids with a square base, the bases of which constitute ends of said orifice, the central zone of this orifice belonging to the two pyramids. This shape composed of two inverted pyramids having their vertices in contact makes it possible to obtain a shape for the orifice 44 whose total volume is less than that of a single pyramid engraved from one of the two ends of the movable member 40 .
• an advantageous solution consists in carrying out an anisotropic etching from the two ends 45 and 46 of the movable member 40. For this, one begins to dig the orifice 44 starting, for example, by the first end 45 of the movable member 40, the etching consisting of a square whose side length decreases as one digs more within the movable member 40 In this way, a first lower portion of orifice 44 is obtained, the section of which decreases until it becomes zero at the place corresponding to the top of the pyramid thus formed.
• an opening 44 opening the same type of etching is carried out as that which has just been described, starting this time from the second end 46 of the movable member 40, the opening 44 then being entirely produced when, during from the second etching, the first portion of the abovementioned orifice 44 is reached, thereby forming an opening 44.
• - section at the center of the orifice 44 of the order of 50 ⁇ m
• - length of the orifice 44 at least half the thickness of the intermediate plate 18.
• an orifice 44 having a substantially constant section over its entire length is produced, for example by means of a reactive ion etching or micro-machining method, an orifice 44 of small diameter is obtained, this diameter possibly being from 10 to 100 ⁇ m ..
• the volume of the orifice 40 has a volume at most equal to one fifth, preferably one tenth, of the unit volume of pumping, that is to say the volume moved at each opening-closing cycle of the pump or the volume moved by each up-down cycle of the pumping membrane 22.
• the ratio between, on the one hand, the maximum distance separating the membrane-shaped part of the nearest wafer and, on the other hand, the thickness of the intermediate wafer is less at 1/20, advantageously of the order of 7 ⁇ m.
• said membrane-shaped part, the first end of the movable member and the outlet of the orifice are adjacent to the first wafer and the outlet of the orifice opens directly into the pumping chamber.
• annular rib 48 surrounding the inlet of the orifice 44 and allowing, when it is in contact against the lower surface of the second plate 20, sealing the inlet valve 28.
• annular rib 48 with a contact surface as small as possible will be preferred so that, on the one hand, the surface which must have an optimum surface state has an area the as low as possible and, on the other hand, so as to produce an inlet valve 28 which can open for a relatively low liquid pressure difference between the inlet duct 14 and the pumping chamber 24.
• the pressure difference allowing the opening of the inlet valve 28 corresponds to the difference in liquid pressure between the liquid present in the connection space 50 placed upstream of the inlet valve 28 and the liquid pressure in the orifice 44, this pressure being the same as in the pumping chamber 24.
• the liquid can pass from the orifice 44 to the pumping chamber 24, in the open position of the inlet valve 28, there is provided, on the surface of the first end 45 of the movable member 40 placed opposite the first plate 12, a series of stop elements 52 under the form of small pillars, one end of which is integral with the first end of the movable member 40 and the second end of which, free, comes to bear against the upper surface of the first plate 12.
• these abutment elements 52 constitute movement limiters for the inlet valve 28 when the latter opens so that, in its opening movement, when the movable member 40 approaches the first plate 12, one is not in a situation where the surface of the first end of the movable member 40 which surrounds the outlet of the orifice 44 comes to bear on the first plate 12 thereby blocking the outlet of the orifice 44.
• a whole series of abutment elements 52 are provided distributed over the first end of the movable member 40.
• the liquid can flow in the direction of the pumping chamber 24 bypassing these stop elements 52.
• the inlet valve 28 closes by itself by a return phenomenon whose origin is explained further. Then, the actuator 26, 126 controls the downward movement of the pumping membrane 22 so that a liquid pressure is obtained in the pumping chamber 24 which is higher than the liquid pressure in the connection space located downstream of the outlet valve 30. In this situation, the outlet valve opens as soon as the pressure difference is sufficient and the liquid flows out of the pumping chamber 24.
• the inlet valve 28 further comprises a first layer of silicon oxide 54 covering at least the surface of the second end 46 of the movable member 40 capable of coming into contact with the second plate 20 in order to '' prevent solidarity between the valve and the second plate in the closed position of the inlet valve 28.
• This first layer of silicon oxide 54 covers at least the annular rib 48 in the zone intended to come into contact with the second wafer 20, this thin layer of silicon oxide making it possible to avoid sticking between the movable member 40 and the second plate 20. So that the inlet valve 28 is closed in its rest position, provision is advantageously made of layers of silicon oxide 56, 58 arranged on the membrane 42 so that it is subjected to a certain prestress towards the top of the figures.
• the oxide layer 56 is arranged at the region of the membrane-shaped part 42 which is adjacent to the movable member 40 and which is turned towards the second plate 20 and the oxide layer 58 is arranged in an area of the membrane 42 furthest from the movable member 40, on the opposite face of the first plate 12.
• the membrane 42 which does not have a constant thickness.
• the inlet valve 28 being preferably machined within the intermediate silicon wafer 18 by means of known photolithographic techniques, it is provided that, preferably, the surface of the first portion 42a faces towards the first wafer 12 is parallel to the surface of the first plate 12 placed opposite the inlet valve 28 and is at the same level as the free end of the stop elements 52 because these two elements are machined simultaneously. Thus these two elements are placed at an identical distance from said first plate 12 when the valve 28 is closed.
• the free end of the abutment elements 52 is planar and parallel to the surface of the first plate 12 adjacent to the pumping chamber 24.
• the inlet valve 28 of FIG. 5 does not include the oxide layers 54, 56 and 58 of FIG. 3 because it is shaped, during its manufacture, to be naturally, that is to say in its rest position, in closed position.
• provision is made for at least the surface of the annular rib 48 facing the second plate 20 and / or at least the surface of the second plate 20 placed opposite the rib annular 48 is treated, for example coated with an anti-adhesion layer, to avoid joining between the valve 28 in the closed position and the second plate 20.
• an inlet valve 28 can be produced with a stepped membrane 42, such as that of FIG. 5, and comprising some or all of the layers of silicon oxide 54, 56 and 58 of FIG. 3. If a layer 58 is provided, this will preferably be limited to the first portion 42a of the membrane 42.
• the variant embodiment illustrated in FIG. 6 corresponds to a non-return inlet valve 28 in the closed position, the position of which has been reversed with respect to that of FIG. 3.
• the membrane 42 is located near the second plate 20 and the seat of the valve 28 is formed by the annular zone of the upper face of the first plate 12 facing the annular rib 48 directed downwards in FIG. 6 and placed on the second end 46 of the movable member 40.
• the stop elements 52 are arranged and the movable member extends radially by the membrane 42.
• the orifice 44 has the same characteristics and can be produced in the same way as in the case of the embodiments presented above.
• an additional orifice 64 similar to the orifice 44, passes through the entire thickness of the intermediate plate 18 downstream of the inlet valve 28.
• micropump comprising an inlet valve 28 according to one of the embodiments which have just been described, it remains identical to that of a micropump of the type of those described in the aforementioned European applications.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Reciprocating Pumps (AREA)
• Details Of Reciprocating Pumps (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=9510392

Family Applications (1)

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• 1998
  • 1998-08-19 WO PCT/EP1998/005471 patent/WO1999009321A1/fr active IP Right Grant
  • 1998-08-19 EP EP98951326A patent/EP1003973B1/de not_active Expired - Lifetime
  • 1998-08-19 CN CN98809517A patent/CN1097168C/zh not_active Expired - Fee Related
  • 1998-08-19 AU AU97398/98A patent/AU9739898A/en not_active Abandoned
  • 1998-08-19 US US09/486,111 patent/US6390791B1/en not_active Expired - Lifetime
  • 1998-08-19 CA CA002301878A patent/CA2301878A1/en not_active Abandoned
  • 1998-08-19 JP JP2000509953A patent/JP2001515183A/ja active Pending
  • 1998-08-19 DE DE69813569T patent/DE69813569T2/de not_active Expired - Lifetime

Non-Patent Citations (1)

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