Improved unidirectional valve device for an infusion line or a medical product and capable of being activated at low pressure of the fluid circulating in this line

Abstract

A unidirectional valve device for a medical line adapted to prevent a flow of fluid in one direction, but to permit it in the opposite direction, comprises a valve body with an inlet (3) and an outlet (4) portion, each portion comprising a tubular connector (5, 6) for connection to the medical line, an elastomeric valve member (8) being provided inside this valve body (2) adapted to intercept the flow of fluid and permit it in only one direction through said valve body (2) when this flow exceeds a predefined pressure value. The elastomeric valve member (8) is flat and comprises a central part (35) from which two arms (36) held by the portions (3, 4) of the valve body (2) extend symmetrically with respect to this central part.

Description

[0001]IMPROVED UNIDIRECTIONAL VALVE DEVICE FOR AN INFUSION LINE OR A MEDICAL PRODUCT AND CAPABLE OF BEING ACTIVATED AT LOW PRESSURE OF THE FLUID CIRCULATING IN THIS LINE The present invention relates to a unidirectional valve device or "check valve" for a medical infusion line or a medical product according to the preamble of the main claim. Valve devices of the aforementioned type have long been used in medical products used in medical lines or in medical and infusion lines in which blood or a saline or physiological solution or other type of medical fluid to be administered to a patient usually intravenously flows. These devices are essentially of two types: valve devices (or simply "valves") which will close in the case of a retrograde flow in the line (i.e. the flow moves in the opposite direction to that required in the medical line) or valve devices which will open in the case of a positive flow (i.e. according to the desired direction within the medical line). The first valve devices are referred to as the "normally open" type, the second valve devices are referred to as "normally closed" valve devices. Such valve devices comprise a valve body with internal ducts associated with connectors for connection to a medical line. A unidirectional valve member is present between the internal ducts. The present invention relates to a valve device or a normally closed valve, that is a valve member which usually closes the connection between the internal ducts of the valve body. With reference to the latter type of valve members ("one-way valve" or "check valve") they require, to be opened (or better, to open the valve member), that the flow circulating in the medical line on which they are installed or in the products inserted in these lines has a pressure equal to or higher than a predetermined valve member, which pressure is indicated as "opening pressure" (also called "cracking pressure"). Usually this opening pressure value should be kept as low as possible, but this often leads to the creation of valve devices provided with more delicate mechanisms than similar mechanisms of valves which open under higher opening pressure values; the use of these more delicate mechanisms, however, affects the ability of the valve device to stop the retrograde flow at high pressures, higher than those resisted by the valve devices with high opening pressures. US2008 / 0169444 describes a valve device with one-way valve for medical infusion lines which comprises a one-way valve defined by a diaphragm made of an elastic material placed between a first and a second portion of a valve body provided with tubular connectors. Said diaphragm is cup- shaped and has an outer peripheral edge usually pushed into sealing contact against its own valve seat having a conical surface under an axial thrust exerted by the side wall of said cup-shaped diaphragm. This solution uses the pressure which is exerted by the retrograde flow in the medical line to exert a pushing force against the side wall of the cup- shaped diaphragm and helps to maintain the seal against the valve seat. US5992462 discloses a valve device with a one-way valve comprising a valve body having a base portion and a cap portion positioned in telescopic relationship with each other and wherein an end chamber of the base portion is contained in a corresponding cup-shaped portion of the cap portion. A disc shaped valve member made of an elastomeric material is positioned within the valve body and is defined by opposing planar surfaces. This valve member comprises a spherical portion located centrally thereon and which is captured between opposing valve supports supported by the cap portion and the base portion, respectively. These opposing valve supports make a seal against the inlet geometry in the valve body, by deformation of the elastomeric valve member. Another prior art document, US2011 / 0108147 describes a valve device having a valve body comprising a first and a second portions provide with a connection tube. Within the valve body and between said portions a one-way valve is provided with a disc-shaped diaphragm arranged within the valve body. The disk-shaped diaphragm has a projecting annular bead protruding from both sides of the disk-shaped diaphragm; said annular bead is suitable to be accommodated in opposite annular grooves of the opposite valve body portions. In this way, the diaphragm is fixed to the valve body along its circumference. Said disc-shaped diaphragm has a plurality of openings made radially and is arranged in a valve seat in the valve body so as to create a seal on a projection, present on the side of a fluid inlet into said body, through a not perforated part of said disk- shaped diaphragm. During use, at first the incoming fluid passes through the disc openings and when the pressure of this fluid exceeds a predefined value, the aforementioned seal is broken. The sealing of the disc on the valve body is due to radially symmetrical forces which stress the disk-shaped diaphragm to cooperate with the wall of the valve seat. In fact, the insertion of the projecting annular bead within the respective grooves generates a pretensioning of the disk-shaped diaphragm which brings the latter against said valve seat and generates the sealing on it. US2021093780 describes an apparatus for preventing backflow, including a housing, a trap flow part forming a flow passage for a medical fluid, a discharge part provided on a lower portion of the housing and to receive the medical fluid from the trap flow part and to discharge the medical fluid. A backflow prevention chamber part is provided between the trap flow part and the discharge part. A plate-shaped backflow prevention member is provided on one surface of the inner side of the backflow prevention chamber part connected to the trap flow part and in close contact with a periphery of the outlet opening. The plate- shaped backflow prevention member is provided to open or close the opening depending on forward flow and the backflow of the medical fluid. The plate-shaped backflow prevention member is hinged at one side to fixing members of the housing and, at the other side, the plate-shaped prevention member is provided with a hole suitable to contain a guide protrusion projecting from a housing part. In this way, if a flow of medical fluid passes through the apparatus towards a patient, the backflow prevention member rotates about the fixing part and its second side moves along the guide protrusion to allow the flow to pass through the apparatus. On the contrary, in case of a backflow, the backflow prevention member is pushed against an opening of the inlet passage of a body of the apparatus and the backflow is stopped. This prior art document does not disclose a “two-stage one way valve” suitable to open even at low pressure conditions but which also ensures a higher flow following the exceeding of a tension force inside of the backflow prevention member, which force arises thanks to the conformation of this valve member and the modes in which it is associated to the housing. In fact, the way according to which the backflow prevention member is connected to the housing limits the movement of said member under the fluid pressure and passing through the inflow passage: at least due to the friction forces which generate between the backflow prevention member and the guide protrusion, the movement of said member to correctly allow said fluid to move are overcome only after said forces are over a threshold value; then the backflow prevention member allows a flow of fluid to freely pass through the trap flow part only after said threshold have been reached and overcome. US2011034907 describes a body fluids drainage system that includes a urinary catheter, a drainage collection bag, and a connection member connected between the urinary catheter and the drainage collection bag. The connection member houses a valve element formed from a sheet of material and projecting a coherent plane. The valve element defines a longitudinal direction extending between a connecting portion and a flap portion and a recess formed on a periphery of the valve element between the connecting portion and the flap portion. The valve element is hinged, inside the connection member, to a first part of the connection member and rotates on this hinge. More in particular, the valve element is located inside a connector of the drainage system which is similar, as to its operation, to the backflow preventing member of US2021093780. In fact, the valve member has a lateral connecting portion provided with integral engagement means suitable to be brought into engagement with retaining means of a first part of the connector of the drainage system. The valve member has a flap portion, in piece with the connecting portion, which can move inside the connector in order to allow or prevent a flow of fluid through the connector. Therefore, also US2011034907 describes a solution where the correct operation of the value element occurs when the pressure of the incoming flow overcome a set threshold and opens the valve element. This is due to the way of connection of this valve element to the first part of the connector of the drainage system. EP1099455 describes a check valve for medical infusion lines and the like; it includes a diaphragm made of elastic material inserted between a first and a second tubular connector and acting on an annular valve seat to keep the check valve normally closed. The diaphragm includes an annular peripheral section and a central disc connected to the peripheral section via a crown of spaced-out arms. The disc is moulded with a thin, axially projecting, circumferential sealing lip on one face or on both faces. The central disc acts as a valve obturator with an annular valve seat encircling an extremity of an inlet passage of the check valve body: if a pressure of the fluid in the inlet passage overcomes a predetermined threshold, the disc central section of the diaphragm moves away from its seat and the fluid may pass through the check valve towards an outlet passage. Should a reflux arise, the pressure in the outlet passage pushes the valve member against its seat and the back flow is prevented. Also in the case of the solution of this prior art, the valve obturator opens when the fluid in the inlet passage has a pressure that is higher than a seat threshold. The object of the present invention is to provide a valve device provided with a one-way valve or check valve for a medical infusion line or for products used in a medical line which is improved with respect to the similar already known one-way valves. In particular, the object of the invention is to provide a unidirectional valve device of the type indicated above wherein the fluid pressure value adapted to allow the opening of the unidirectional valve member is minimized, but wherein there is in any case an effective blocking of the retrograde flow returning to the valve from the medical line. According to the above object, the invention provides a unidirectional valve device which is simple but that can also be opened at low pressure conditions so to allow a minimum flow of fluid to be created in the medical line. Another object of the present invention is to provide a unidirectional valve device of the aforementioned type which has a limited number of components and can be obtained in a short time and at low costs. These and other objects which will be evident to those skilled in the art are achieved by a unidirectional valve device according to the attached claims. For a better understanding of the present invention, the following drawings are attached purely by way of non- limiting example, in which: Figure 1 is a perspective view of a one-way valve device according to the invention; Figure 2 is an exploded perspective view from one side of the valve device of Figure 1; Figure 3 is an exploded perspective view from the other side of the valve device of Figure 1; Figure 4 is an exploded front view, with some parts in transparency, of the valve device of Figure 1; Figure 5 is an enlarged perspective view of a component of the valve device of Figure 1 before assembly; Figure 6 is a top view of the valve device of figure 1; Figure 7 is a sectional view along line 7-7 of Figure 6; Figure 8 is a sectional view along line 8-8 of Figure 6; figure 9 is an enlarged view of the part indicated with A in figure 7; figure 10 is an enlarged view of the part indicated with B in figure 8; figure 11 is a perspective view from one side of a different embodiment of a one-way valve device according to the invention; figure 12 is an exploded view, from one side, of the valve device of fig. 11; and figure 13 is an exploded view, from another side, of the valve device of fig. 11. With reference to the aforementioned figures, a valve device with one-way valve (or check valve) is generically indicated by 1. The valve device 1 comprises a valve body 2 having a first portion 3 and a second portion 4, both having a per se known tubular connector, respectively 5 and 6, adapted to connected the valve body 2 to tubes of a medical line or to the body of a medical product inserted in this line (such as a filter inserted in a medical infusion line), not shown. A recess 7 is provided around each connector 5 and 6, in the respective portion 3 or 4, to facilitate this connection. In figures 1-4, arrows F and H indicate the direction of the fluid flow within and outside the valve body 2. Inside the valve body 2 there is a valve component or member 8; the valve member 8 is placed between internal ducts 10 and 11 of the first portion (or inlet portion) 3 and the second portion (or outlet portion) 4, respectively, connected to the tubular connectors 5 and 6; this valve member 8 is made of an elastomeric material and adapted to interrupt the connection between said internal ducts 10 and 11 when the pressure of a fluid present within the medical line at the inlet portion 3 is lower than a predefined value for example to 0.05 psi or 0.0034 bar. The valve member 8 subjected to a different and higher pressure can be elastically deformed in such a way as to put said ducts 10 and 11 in communication and allow a medical fluid of a saline or blood solution to pass through the valve body 2 and therefore between the two connectors; however, the valve member 8 shall also block the reverse flow of this fluid from the outlet portion towards the inlet portion by closing the connection between the aforementioned ducts 11. In this way, said valve member operates as a one-way valve. More specifically, each internal duct 10 and 11 of the valve body 2 opens at a surface, respectively 3A and 4A, of the inlet 3 and outlet 4 portions. These surfaces face each other and are in mutual contact. The surfaces 3A and 4A are formed on raised parts 15 and 16 of the inlet portion 3 and the outlet portion 4, respectively. These parts 15 and 16 are internal parts of said portions 3 and 4, with reference to their position in the valve body 2; the valve element 8 is placed between them. In the embodiment shown in Figures 1-10, said parts 15 and 16, when coupled, define an annular or perimeter cavity 19 adapted to receive a thermoplastic material in an overmoulding operation to which the portions 3 and 4 are subjected after being associated (bringing the surfaces 3A and 4A in contact), and after the insertion of the valve element 8 between them. This overmoulding joins the portions 3 and 4 and defines the final conformation of the valve body 2. It should be noted that the duct 10 opens, at 10A, into a transverse recess 23 (i.e. placed with the longitudinal axis K orthogonal to the longitudinal axis W of the valve body 2, see figure 3) presenting a central hollow circular area 24, from the opposite sides of which hollow lateral areas 25 substantially rectangular in shape elongate directed towards the perimeter annular cavity 19. The duct 10 opens at 10A at the central area 24. As can be seen for example in Figures 7-10, this opening 10A of the duct 10 is substantially conical, widened towards the central hollow area 24 and is delimited, laterally within the hollow, rectangular side areas, by protrusions 26 and 27, orthogonal to the axis K, thus placed at the opposite sides of this opening 10. Furthermore, the side areas 25, besides containing the aforementioned protrusions 26 and 27, have an increasing depth towards their end 25F placed in proximity to the perimeter annular cavity 19, said ends 25F being delimited by an end stepped edge 28. Similarly, the duct 11 opens in 11A within an oval or elliptical cavity 30 (with the major axis parallel to the axis K) made in the outlet portion 4, a cavity which in turn opens in the surface 4A of this outlet portion. In the cavity 30 there are projections 31 facing the surface 4A, whose function will be described below. The oval or elliptical cavity 30 thus has an orthogonal arrangement to that of the protrusions 26 and 27. From the surface 4A, moreover, at the hollow side areas 25 of the inlet portion 3, there are projections 33 facing towards these hollow areas 25. The projections have a wedge shape, lower towards the oval cavity 30 (from the edge 30A or near the edge 30A of which they branch off) and rise towards one of their ends 33B facing the perimeter annular cavity 19. Each of these ends 30B ends with an end stepped edge 38 near a corresponding recess 34 provided in the surface 4A which connects to the aforementioned cavity 19. In the recess 23 and above the aforementioned projections 33 there is the valve member 8 which substantially "copies" the shape of the recess 23. Therefore, the valve member 8 has a central portion 35 with a rounded edge (and which we will define "circular") and from which opposing arms 36 branch off, ending with end flanges 37 projecting orthogonally from both sides 36A, 36B of each arm at one of the free end thereof. The valve member, considered autonomously and when not inserted within the valve body 2, is substantially flat, that is its central portion 35 and its arms 36 are on the same plane or, as in the embodiment of figures 11-13, the central portion 35 (which is flat) lies on a first plane while the arms lie on a second different plane located very close and parallel to the first plane. More specifically, the central portion 35 of the valve member 8 is adapted to be positioned at the central hollow area 24 of the transverse recess 23 of the first portion so as to rest with its opposing arms 36 on the protrusions 26 and 27 provided in such recess. The circular central portion 35 is positioned in front of the projections 31. The arms 36 of the valve member 8 are positioned on the wedge-shaped projections 33 and have the end flanges 37 perpendicular to the arms 36 which abut against the end stepped edges 28 and 38 mentioned above, engaging them. The central portion 35 of the valve member 8, moreover, when not subjected to any fluid pressure present in the ducts 10 and 11, closes the connection between these ducts. In addition, due to the engagement between the flanges 37 and the stepped end edges 28 and 38, the valve member is kept under tension along its arms 36 i.e. in the K axis (arrow X in Figure 5); a tension in the W axis of said valve member is created by its cooperation with the projections 33, 26 and 27. This tension obviously arises when the valve body 2 is assembled and subjected to overmoulding with thermoplastic material which forms a portion 40 within the annular cavity 19, which material and operation binding the three parts of the valve device (the portions 3, 4 and the valve 8) in a safe and permanent way, and also creating a total seal around the annular member 8; this member, however, is not affected by this overmoulding and can move freely within the body 2 so as to act as a one-way valve which only opens when the pressure of a medical fluid entering the valve body 2 from the duct 10 exceeds a predetermined value. The tension in the valve member is both perpendicular to the direction (allowed or positive) of the flow (i.e. along the axis W of the valve body 2) through said device, and axially aligned to the retrograde flow of that fluid i.e. returning to the valve body 2 from the line through the duct 11 moving in a direction opposite to arrow H. When the pressure of the fluid entering the duct 10 exceeds a predetermined but relatively low value, the parts of the circular edge of the central portion 35 of the valve member which are not directly parallel to the lines of force along the arms 36 (and also along the part of the central portion 35 aligned with these arms) can be raised by the above-mentioned projections, allowing a minimum flow of fluid to be created around the unidirectional valve member 8. There is, therefore, a positive flow of fluid between the duct 10 and the duct 11 (see Figures 6-10). When the pressure of the fluid increases, it is able to completely deflect the central portion 35 of the valve member towards the oval cavity 30 so as to allow a greater flow of fluid between the ducts 10 and 11. This deflection is limited by the projections 31 present in this cavity oval 30. In this way, the valve device according the invention operates as a two-stage one-way valve according to the pressure value of the circulating fluid. In fact, at a first, low pressure of the circulating fluid there is a limited opening of the valve member; when the pressure overcome another, higher value (for example usually higher than 0,07 bar), the valve member completely opens. This double stage is also allowed by the conformation of the recess 23 with variable depth towards the edges or towards the circumferential cavity 19 which allows the valve member to deform allowing an increased flow between the ducts 10 and 11. The valve device obtained according to the invention allows to ensure a unidirectional flow of the fluid when this is required, between the duct 10 of the inlet portion 3 and the duct 11 of the outlet portion 4. This valve device has a unidirectional valve member which can be opened even at low pressure conditions (for example equal to 0.05-0.07 psi or 0.0034-0.0048 bar), but which also ensures a higher flow following the exceeding of a tension force inside of the valve member 8, which force arises thanks to the conformation of this valve member 8 and the modes in which it is associated with the valve body 2. At the same time, this valve member 8 ensures that the communication between the aforementioned ducts 10 and 11 is completely closed towards a retrograde flow of fluid, i.e. a flow that moves in a direction opposite to that required for medical use in the medical line to which the device 1 is associated. The various components of the device 1 are obtained by moulding; moreover, according to the embodiment of Figures 1-10 as well as the assembly of these components is obtained by overmoulding the thermoplastic material that defines the portion 40 of this valve device. It should be noted that to facilitate the positioning of the coupled portions 3 and 4 (and between which the valve member 8 is present) within the mould to perform said over moulding, the portions 3 and 4 have a faceted external conformation. Figures 11-13 show a different embodiment of the valve device 1. In these figures, parts corresponding to those already described are indicated with the same numerical references. The main difference between the solution of the figures 11-13 with respect to that of figures 1-10 lies in the bonding modality between the first portion 3 and the second portion 4, a bond which is obtained by ultrasonic welding. For this purpose, a first between the inlet portion 3 and the outlet portion 4 (in the figures, the portion 3) has a recess 80 around the internal part 15 delimited externally by a peripheral edge 81 of the aforesaid portion. The second portion (in the figures, portion 4), on the other hand, has a wall 82 extending around the internal part 16, said wall 82 being able to be introduced into the aforementioned recess 80. In the assembly, after the aforementioned coupling between the wall 82 and the recess 80, the ultrasonic welding of the portions 3 and 4 is carried out in correspondence with this wall 82 and recess, binding said portions 3 and 4 in a definitive way. Preferred embodiments of the invention have been described; still others can in any case be realized, such as the one wherein the characteristics of the portions 3 and 4 previously described and the portions themselves are exchanged with each other. This embodiment, too, is the object of the invention, the characteristics of which are however defined by the following claims.

Claims

CLAIMS 1. A unidirectional valve device for a medical line or a medical product adapted to be placed in such medical line, said valve device (1) being adapted to permit a flow of fluid only in one direction within this line or medical product, but intercepting said flow in the opposite direction, the valve device (1) comprising a valve body (2) having an inlet portion (3) and an outlet portion (4), each of these portions (3, 4) comprising a connector member (5, 6) for connection to the medical line or to the medical product, said connector members (5, 6) being connected to ducts (10, 11) inside said valve body (2), a unidirectional valve member (8) arranged within a respective seat (23) inside said valve body (2) being provided between said internal ducts (10, 11), said valve member (8) being made of an elastomeric material said valve member (8) including an enlarged central area (35) from which opposing arms (36) symmetrically branch off, said arms being elongated along a common longitudinal axis (K), the enlarged central area (35) of said valve member having rounded edges connecting said elongated arms, said enlarged central area being provided between said internal ducts (10, 11) of said valve body (2) so as to intercept or allow the connection between said internal ducts (10, 11), the valve seat (23) having a shape matching that of the valve member (8) which is retained within said seat and kept therein in a configuration stressed in traction, characterized in that said valve seat (33) comprises protrusions (26, 27) on which the opposing elongated arm (36) lie, said protrusions (26, 27) being placed orthogonally to the longitudinal axis (K) of the opposing elongated arms, these opposing elongated arms (36) being located between said seat protrusions (26, 27) and projections (33) facing the valveseat protrusions (26, 27) located inside the valve body (2).

2. The valve device according to claim 1, characterized in that the seat prortrusions (26, 27) are on a first portion between the inlet portion (3) and the outlet portion (4), the projections (33) are on the second portion between the inlet portion (3) and the outlet portion (4).

3. The valve device according to claim 1, characterized in that the enlarged central area (35) of the valve member (8) has a circular shape, the elongated arms (36) projecting symmetrically from said central area (35).

4. The valve device according to claim 1, characterized in that said valve member (8) is flat.

5. The valve device according to claim 1, characterized in that said elongated opposing arms (36) have opposite sides (36A, 36B) and end at one of the free ends thereof with opposite end flanges (37) projecting orthogonally from said opposite sides (36A, 36B).

6. The valve device according to claim 5, characterized in that said flanges cooperate with end steps (28, 38) of the valve seats (23).

7. The valve device according to claims 1 and 5, characterized in that said valve seat (23) comprises a transverse recess made within an internal area (15) of at least one first between the inlet portion (3) and the outlet portion (4) of the valve body (2), a corresponding internal duct (10, 11) of said valve body (2) opening in said recess, said valve seat (27) having a central hollow area (24) in which said internal duct opens (10, 11) adapted to contain the enlarged central area (35) of the valve member (8) and hollow elongated areas (25) placed laterally to said hollow central area (24) adapted tocontain said opposing elongated arms (36) of said valve member (8), said hollow elongated areas (25) ending with an end and stepped edge (28) with which the end flanges (34) of the aforementioned opposing elongated arms (36) cooperate by engagement.

8. The valve device according to claim 7, characterized in that the protrusions (26, 27) provided within said valve seat (23) are placed on the opposite sides of the central hollow area (24).

9. The valve device according to claim 7, characterized in that an oval or elliptical cavity (30) is provided within an internal area (16) of the second portion between the inlet portion (3) and the outlet portion (4) of the valve body, said oval or elliptical cavity (30) opposing the central hollow area (24) of the transverse recess (23) made within the first portion, between said inlet and outlet portions (3, 4) and laterally to said oval or elliptical cavity the projections (33) facing towards the elongated hollow areas (25) of said transverse recess (23) being provided, said projections having a wedge shape and lowering at one end towards the oval or elliptical cavity, the other end forming a step (38) with said internal area (16) with which a corresponding end flange (34) of one of the opposing elongated arms (36) of the valve member cooperates.

10. The device according to claim 7, characterized in that said hollow elongated areas (25) have increasing depth moving away from the central area (24).

11. The device according to claims 7 or 9, characterized in that said internal areas (15, 16) of said inlet (3) and outlet (4) portions are raised on the respective portions, the coupling of said inlet and outlet portions (3, 4) bringing these internal areas to define aperimeter annular cavity (19) on the valve body (2).

12. The device according to claim 11, characterized in that said perimeter annular cavity contains a portion (40) in a thermoplastic material overmoulded on said inlet and outlet portions (3, 4).

13. Device according to claim 1, characterized in that said inlet and outlet portions (3, 4) are ultrasonically welded.

14. Device according to claim 13, characterized in that a first portion between one of the inlet portion (3) and the outlet portion (4) has an internal recess (80) adapted to receive an internal wall (82) of the second portion between the other of the inlet portion (3) and the outlet portion (4), said inner wall (82) being ultrasonically welded into the inner recess (80).

15. Device according to claims 7, 9 and 14, characterized in that said internal wall (82) is made around the internal part (16) of the second portion between one of the inlet portion (3) and the outlet portion (4 ), the internal recess (80) being provided between the internal part (15) of the first portion between the other of the inlet portion (3) and the outlet portion (4) and a peripheral edge (81) of this first portion.

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