WO2013010580A1

WO2013010580A1 - Anti free flow valve

Info

Publication number: WO2013010580A1
Application number: PCT/EP2011/062275
Authority: WO
Inventors: Giancarlo Gagliardoni; Jan Willem Marinus Mijers
Original assignee: Cedic S.R.L.
Priority date: 2011-07-18
Filing date: 2011-07-18
Publication date: 2013-01-24
Also published as: EP2593175A1

Abstract

Valve (3) for engaging with a tube to be used in an enteral feeding or infusion pump adapted to feed a fluid to a patient comprises a first portion (9) having a first cavity (20) and adapted to be connected to a first tube, a second portion (13) having a second cavity (17) and adapted to be connected to a second tube (7), a resilient portion (11) having a cavity connecting the first portion (9) and the second portion (13), and a blocking portion blocking the flow of fluid between the first tube and the second tube (7) when the valve (3) is in the closed position, wherein the resilient portion (11) comprises an expansion reserve (27) adapted to release the flow of fluid between the first tube and the second tube (7) when the first (9) and the second (13) portions are moved away from each other in opposite directions to bring the valve (3) into the open position.

Description

Anti Free Flow Valve

BACKGROUND OF THE INVENTION The present invention relates to an anti free flow tube valve to be used with an enteral feeding pump adapted to feed nutritionals or an infusion pump adapted to infuse medical solutions to a patient. More particularly, the present invention relates to a tube valve connected to a tube which may be fitted into a cassette for use on enteral feeding sets or infusion sets and the like, wherein the tube valve prevents the free-flow of enteral formula through the enteral feeding set or of solutions through the infusion set unless the tube with the tube valve mounted in the cassette is properly mounted in a housing or some other structure of an enteral feeding pump or infusion pump.

The use of infusion and feeding sets to administer solutions and food to a patient is well known in medical arts. Infusion and enteral sets are used for both enteral and parenteral application, respectively. For hygienic reasons the infusion and enteral sets must be disposed of immediately after use, making it single-use equipment which may be recycled afterwards. Enteral feeding pumps are used to provide the patient with nutrition and medication (formula) when they are unable, for a variety of reason, to eat normally. Parenteral (in- travenous) solutions are provided to patients to ensure adequate hydration and to provide needed nutrients, minerals and medication. Often, the enteral or infusion set is placed in a free standing arrangement in which gravity forces the formula or solution into the patient. The rate at which the solution enters the patient can be roughly controlled by various clamps, such as roller clamps, which are currently available on the market.

In many applications, it is necessary to precisely control the amount of solution or formula which enters the patient. When this is the case, a regulating device such as an infusion pump, is placed along the infusion set to control the rate at which the solution is fed to the patient. In applications where a pump etc. is used the clamps or valves used to regulate flow are typically open to their fullest extent to prevent the clamp or valve from interfering with the proper functioning of the pump. The clamp or valve is opened with the expectation that the enteral feeding pump or infusion will control fluid flow through the enteral or infusion set. However, emergencies or other distractions may prevent the medical personnel from properly loading the enteral or infusion sets in the enteral feeding pump or the infusion pump. Furthermore, the enteral or infusion sets may be inadvertently dislodged from the pump during operation of the pump.

In many enteral feeding systems the engagement of the pump tube to the rotor controls the flow of fluid to the patient according to the speed of the rotor (peristaltic pump). In the event the enteral feeding set is not properly mounted to the pump, an excess flow of fluid through the feeding set can occur under force of gravity known as free-flow often develops which is highly undesirable. Under a free-flow condition, an amount of solution or formula many times the desired dose can be supplied to the patient within a relatively short time period. This can be particularly dangerous if the solution contains potent medicine or the patient's body is not physically strong enough to adjust to the large inflow of solution or formula.

US 4,913,703, US 5,201 ,71 1 , and US 6,017,326 disclose a safety interlock system for a flow control apparatus provided with a magnetic field source in the region of its mounting to an administration feeding set having a magnetic source, such as a magnet, incorporated into the mounting member. The flow control apparatus includes a magnetic field sensor switching component which detects the proper placement of administration feeding set in the recess of the flow control apparatus and prevents the operation of the flow control apparatus unless the mounting member of the administration feeding set is in a properly en- gaged position in the pump. Such apparatus is complex and requires a magnetic field, corresponding sensors etc. which increase the cost of this medical equipment significantly.

WO 2010/149187 A1 discloses a pinch clamp assembly with a cassette as a base element and a clamp wherein the silicone tube is in an anti free flow condition as long as the as- sembly is not attached to the pump. The cassette comprises attachment means for the silicone tubing on either side such that the central part of the tubing may be stretched when inserted into the pump with a peristaltic motor mechanism. However, this assembly comprises a plurality of elements such as a spring and a clamp which render the construction rather complex.

Thus there is a need for a device that prevents a free-flow condition if the enteral or infusion set is not properly mounted in the pump or other regulation means. It is furthermore important that the device is tamper-resistant with regard to the generation of the free-flow condition. The device should be simple in structure and small in size, easy to handle and com- patible with the majority of existing pump devices. SUMMARY OF THE INVENTION

It is therefore the object of the present invention to provide a valve for engaging with a tube to be used in an enteral feeding or infusion pump which comprises a full anti free flow func- tionality, i. e. which ensures a closed state when assembled in a cassette of an enteral feeding or infusion pump, which on the other side allows liquids to be pumped through when mounted on a pump, which is of a simple construction thus ensuring low manufacturing costs, small in size, and which is compatible with the majority of existing pump devices. This object is solved by the features of claim 1. Advantageous embodiments of the invention are subject of the subclaims.

According to the invention, a valve for engaging with a tube to be used in an enteral feeding or infusion pump adapted to feed a fluid to a patient comprises: a first portion having a cav- ity and adapted to be connected to a first tube, a second portion having a cavity and adapted to be connected to a second tube, a resilient portion having a cavity connecting the first portion and the second portion, and a blocking portion blocking the flow of fluid between the first tube and the second tube when the valve is in the closed position, wherein the resilient portion comprises an extension reserve adapted to release the flow of fluid be- tween the first tube and the second tube when the first and the second portions are moved away from each other in opposite directions to bring the valve into the open position. The expansion reserve of the resilient portion ensures that only this particular area of the resilient portion is responsible for opening and closing the valve by pulling the first portion and the second portion apart in opposite directions the valve is brought from the closed into the open position, and as soon as the pulling force is no longer existent the valve will go back into the closed position due to the elastic retraction characteristics of the resilient portion. It is understood that for moving away from each other, analogously, one side of the valve may be fixed and the other may be pulled away to open the valve. In the open position of the valve fluid is allowed to flow from the first tube to the second tube or vice versa. The capac- ity of the cavities of all components ensures a sufficient flow of fluid necessary to fulfil the infusion or enteral feeding requirements.

It is preferred that the first portion, the second portion and the resilient portion are rotation- ally symmetric and aligned along a central axis. Rotationally symmetric in the sense of this feature means that the respective components are substantially cylindrical and have a cir- cular outer cross section and inner cross section of the cavities which enables a simple structure and thus facilitates a less costly manufacture. However, it should be noted that deviations from this rotational symmetry are possible, i. e. for attaching the valve according to the invention into a cassette of a pump.

Preferably, the expansion reserve of the resilient portion includes at least one bellow. The shape of a bellow improves the transfer of the stretching or pulling force easier to open the valve. It should be noted that the bellow does not negatively influence the elastic characteristics of the expansion reserve, however, the force necessary to expand the resilient portion decreases in comparison with a purely flat expansion reserve. The expansion reserve has the function of a spring element which goes back in to its original position when no longer being pulled apart or stretched.

It is further preferred that the blocking portion comprises a first blocking part and a second blocking part engaging with each other when the valve is in the closed position. The engagement of the first blocking part and the second blocking part ensures a tight fit such that in the closed position the anti-free flow valve remains closed under a pressure of a minimum of 180 mbar. Advantageously, the first blocking part is formed of relatively hard thermoplastic polymer material such as polypropylene (PP), polyvinylchloride (PVC) and poly- ethylene (PE) and the second blocking part is formed of relatively soft thermoplastic elastomer (TPE) material or silicone rubber material. By pressing a soft rubber material onto a hard plastic material the blocking function can be ensured even under the above-mentioned pressure conditions. Other similar material may be used provided that they satisfy the described functional requirements.

It is further preferred that the first blocking part comprises a central radial surface and an outer radial surface connected by a plurality of links so as to form a plurality of channels wherein the central radial surface is configured to engage with a ring surface of the second blocking part. It must be noted that the central radial surface, the outer radial surface and the ring surface must be parallel to each other to ensure a good engagement. It must further be mentioned that the size of the central radial surface and the corresponding size of the ring surface are configured such that the compressing force of both elements withstands the required pressure of the fluid. This means that the bigger the central radial surface and the ring surface, the smaller the compression force exerted by the expansion re- serve. Considering these facts together with the requirement of the necessary flow through the first and the second tube it can be calculated which size of the central radial surface and the channels provides a good compromise between the necessary compression force and the required flow. Preferably, the central radial surface includes a protrusion extending into a corresponding recess of the second blocking part. This protrusion prevents the unwanted opening of the valve by bending, i. e. if the flat radial surfaces of the first blocking part and the second blocking part are disengaged by bending the resilient portion of the valve according to the invention, the protrusion ensures that in the particular area of the two mating surfaces no disengagement will occur.

The first blocking part may alternatively be formed integrally with the first portion, the second portion or the resilient portion. Depending on the material used, the more complex structure of the first blocking part may be used with the material of the first portion or the second portion so as to safe manufacturing and tooling costs.

It is further preferred that the first portion comprises a first component and a second component configured to engage one end of the resilient portion between each other. Since the expansion reserve of the resilient portion is located on the outer perimeter of the resilient portion it is clear that the end of the resilient portion in the direction of the first portion must be firmly attached so as the resilient portion cannot become loose when the pulling force is applied in opposite directions to the first and second portions. Thus, that end of the resilient portion should be configured for optimum attachment with the first portion. Dividing the first portion into a first component and into a second component makes it possible to engage that end between the first component and the second component which may be assembled together with the resilient portion using pressurized air.

Alternatively, the resilient portion may be attached to the first portion by gluing, bonding, clamping or any other appropriate attachment method.

It is furthermore advantageous, that the resilient portion and the second portion are integrally formed. This may save additional manufacturing cost by combining two functions into one component, which does not negatively influence the overall function of the valve according to the invention. Adequate manufacturing methods for all components include injec- tion molding, double injection molding, liquid injection molding (LIM) and other adequate methods known in the art.

The material of the resilient portion is preferably silicon rubber or a thermoplastic elastomer (TPE). Both materials can be injection molded, double injection molded or manufactured by liquid injection molding according to methods which are known in the art. The material of the first portion is preferably a thermoplastic polymer material. This material is readily available at low costs and can be molded as mentioned above. It is further preferred that the first portion comprises a recess adapted to engage with a cassette of the enteral feeding or infusion pump. Such a cassette is in principle disclosed in WO 2010/149187 A1 . When the valve including its tubing is engaged and thus firmly attached with the cassette of the enteral feeding pump there is a definite point where the pulling force is applied. For the present invention this means, that it is also possible to only pull at one end, i. e. at the second portion of the valve, to effect the opening of the valve according to the invention. Thus, the present invention also works if one side of the valve is firmly attached and the opposite side is pulled away from the attachment point.

Advantageously, the first portion comprises an outer flange adapted to attach the valve to a corresponding recess in a pump. In the prior art there exist pumps which do not comprise a cassette into which the silicon tubing including the valve is inserted. In contrast, the silicon tubing is attached at the outside of the pump and led around a peristaltic element in a 180° fashion. Providing a flange at the first portion of the valve will enable the valve according to the invention to be used in such a pump wherein the outer flange can be firmly attached to the corresponding recess in the pump. Therefore, the valve of the present invention can be used in such a pump without changing the setup or any elements of the pump.

BRIEF DESCRIPTION OF THE DRAWINGS The above object, features and advantages of the present invention will become apparent from a consideration of the following detailed description presented in connection with the accompanying drawings in which:

Fig. 1 and 2 are a perspective view and a sectional view, respectively, of a valve assembly comprising a first embodiment of the present invention, is a section view of a first embodiment of the valve according to the invention showing one end of the valve assembly depicted in Fig. 2; are a perspective view and a sectional view, respectively, of a first component of the first embodiment; is a sectional view of a second component of the first embodiment according to the invention; is a sectional view of a second embodiment of the valve according to the invention; is a sectional view of the second component used in the second embodiment according to the invention; is a sectional view of the resilient portion and the second portion used in the second embodiment of the present invention; is a perspective view of the resilient portion and the second portion shown in Fig. 9 according to a second embodiment of the present invention; is a sectional view of a third embodiment of the valve according to the invention; are a perspective view and a sectional view, respectively, of a first component of the third embodiment according to the invention; are a perspective view and a sectional view, respectively, of a second component used in the third embodiment as shown in Fig. 1 1.

Figs. 16 is a sectional view of the resilient portion and the second portion as used in the third embodiment shown in Fig. 1 1 ; Fig. 17 is a sectional view of a fourth embodiment of the valve according to the invention;

Fig. 18 is a sectional view of the resilient portion and the second portion used in the fourth embodiment as shown in Fig. 17;

Fig. 19 is a sectional view of the resilient portion used in the fourth embodiment as shown in Fig. 17; Figs. 20 and 21 are a perspective view and a sectional view, respectively, of a second component used in the fourth embodiment as shown in Fig. 17; is a perspective and partly sectional view of the second component and the resilient portion of the fourth embodiment as shown in Fig. 17; is a partial perspective view of a peristaltic pump of the prior art; are a sectional view and a perspective view, respectively, of a fifth embodiment of the valve according to the invention; is a sectional view of a sixth embodiment of the valve according to the invention;

Fig. 27 is a sectional view of the resilient portion and the second portion used in the sixth embodiment as shown in Fig. 26;

Figs. 28 and 29 are a perspective view and a sectional view, respectively, of a first portion used in the sixth embodiment as shown in Fig. 26. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Fig. 1 shows a perspective view of a first embodiment of the valve according to the invention in a valve assembly 1 . The valve assembly 1 comprises a first tube (not shown), a valve 3, a tube entry 5 and a second tube 7 connecting the valve 3 and the tube entry 5. The second tube 7 may be made of silicon rubber material which is flexible so that it can be inserted into a cassette (see WO 2010/149187 A1 ) of an enteral feeding pump or an infusion pump or directly mounted on such a pump. When used in a cassette the valve 3 and the tube entry 5 are usually attached to corresponding holding fixtures so that each end of the second tube 7 is firmly fixed.

Fig. 2 shows a sectional view of the valve assembly 1 as shown in Fig. 1. Valve 3 at the one end of the valve assembly 1 will be in detail explained with reference to Fig. 3 and tube entry 5 located at the other end of valve assembly 1 is known in the prior art so that a further detailed description is omitted. From Fig. 2 it can be seen that in the case where valve 3 is in the open position a fluid entering the second tube 7 at tube entry 5 will be able to pass through a valve 3 and exit valve 3 via the first tube (not shown).

Fig. 3 shows a sectional view of a valve 3 according to a first embodiment of the present invention. Valve 3 comprises a first portion 9, a resilient portion 1 1 and a second portion 13 wherein in this embodiment the resilient portion 1 1 and the second portion 13 are integrally formed out of silicone rubber material by (liquid) injection molding. The second portion 13 is substantially identical with the second tube 7 having a second cavity 17. First portion 9 which is to be connected to the first tube comprises a first component 19 and a second component 21 which is firmly pressed into first component 19 combining first cavity 20 with the cavity of the second component 21. Second component 21 and first component 19 are at their respective ends which are directed to the resilient portion 1 1 configured at their perimeter such that the corresponding end of resilient portion 1 1 is clamped between second component 21 and first component 19. In order to provide a good clamping function first component 19 comprises a clamping recess 23 adapted to engage with a corresponding clamping protrusion 25 of the resilient portion 1 1. It is contemplated that the attachment of the resilient portion 1 1 to the first portion 9 may be done by other known attachment methods such as bonding, clamping with a ring or the like.

The resilient portion 1 1 also comprises a key element of the valve according to the inven- tion which is the expansion reserve 27 located at the outer perimeter of resilient portion 11. This expansion reserve 27 functions as a spring element opening and closing valve 3 upon applying a force on the second portion 13 in an axial direction, i. e. a long axis 29 so as to pull apart first portion 9 from second portion 13. The expanding and retracting of the expansion reserve is fully reversible. The actual blocking of the flow of fluid from second cavity 17 to first cavity 20 or vice versa is performed by a blocking portion inside resilient portion 1 1. The blocking portion includes a first blocking part 29 which is a radial surface on second component 21 and a second blocking part 31 located inside resilient portion 1 1 and connected to the outer shell of resil- ient portion 11 by a plurality of links 33. In the present embodiment the number of links 33 is four such that there are also four channels 35 formed in the inside of resilient portion 1 1 through which the fluid may flow upon opening of valve 3. As can be seen from Fig. 3 valve 3 is in the open position which means that expansion reserve 27 is expanded and thus the first blocking part 29 and the second blocking part 31 are not engagement with each other so as to allow the flow of fluid from second cavity 17 through channels 35 into first cavity 20. As soon as the tension on the expansion reserve 27 of resilient portion 1 1 is released the valve 3 moves from the open to the closed position wherein first blocking part 29 and second blocking part 31 are in engagement with each other. As second blocking part 31 is made of the same material as the entire resilient portion 1 1 the relatively soft silicone rubber material is pressed onto the hard plastic surface of first blocking part 29 which is part of the second component 21 made of a thermoplastic polymer material which is polypropylene (PP) in the case of embodiment 1.

Resilient portion 1 1 comprises a tapered outer shape when reducing the diameter to the smaller diameter of second portion 13. This ensures that as much stretching or pulling force as possible can be transferred from second tube 7 to expansion reserve 27 which is one of the key components of valve 3.

It should be noted that the dimensions of the inner cavities of all components of valve 3 are such that the flow requirements of any enteral feeding system or infusion system are fulfilled, i. e. the space inside resilient portion 1 1 freed by disengaging first blocking part 29 and second blocking part 31 and the space of the channels 35 are sufficiently large to allow enough fluid to pass between second tube 7 and the first tube. Figs. 4 and 5 show a perspective view and a sectional view, respectively, of the first component 19 used in the first embodiment shown in Figs. 1 to 3. One end of first component 19 is configured to be attached to the first tube (not shown), the other end is configured for optimum engagement with second component 21 and resilient portion 1 1. Furthermore, first component 19 comprises two mounting recesses 37 such that valve 3 can be firmly at- tached to a cassette when used with a respective pump. It can also be seen in Figs. 4 and 5 that clamping recess 23 provides space for clamping protrusion 25 of resilient portion 1 1. Fig. 5 shows that the first cavity 20 comprises a larger inner diameter towards the end which is directed to resilient portion 1 1. This enlargement is targeted to provide a press fit of second component 21 which is inserted into first component 19. Instead of a press fit, the first component 19 and the second component 21 may be glued or bonded together.

Fig. 6 shows a perspective view of second component 21 used in the first embodiment of the valve according to the invention. The end with the larger diameter includes first blocking part 29 which in this embodiment is a plane, circularly shaped surface perpendicular to the flowing direction. Second component 21 is further configured to be hollow such that first cavity 20 may provide its volume for the flow of fluid when the valve is open. It should be noted that in the first embodiment first component 19 and second component 21 are made of polypropylene (PP) which is easily moldable according to known methods. Fig. 7 is a sectional view of a second embodiment of a valve 3 according to the invention. In principle, the concept and construction of the second embodiment is very similar to the one of the first embodiment, the difference is substantially the design of the resilient portion 1 1 which instead of a flat expansion reserve 27 comprises a bellow 39. Further, the second embodiment does not comprise a tapered configuration of the resilient portion: The resilient portion 1 1 comprises a step like transition between the resilient portion 1 1 and the second portion 13. The effect of these differences is that the bellow-like shape of the expansion reserve 27 enables an easier transfer of the pulling or stretching force from the second portion 13 to the resilient portion 1 1. The bellow 39 can be manufactured according to known molding techniques, and the shape and material of the bellow 39 ensures that the function as expansion reserve 27 or spring-like member is preserved. The interior of the resilient portion 1 1 is substantially identical to the one of the first embodiment; however, due to the different structure of the transition area between the resilient portion 1 1 and the second portion 13 the design of the links 33 and channels 35 as part of the inner life of the resilient portion 1 1 differs slightly. It should be noted that the characteristics of the flow of fluid from one side to the other are not influenced by this design modification.

A further minor difference can be seen in the way how the resilient portion 1 1 is clamped between the first component 19 and the second component 21. In the second embodiment shown in Fig. 7 the second component 21 comprises the clamping recess 23 into which the clamping protrusion 25 of the resilient portion 1 1 engages. This clamping setup is oriented in the opposite direction compared with the first embodiment shown in Fig. 3.

Fig. 8 shows the second component 21 in sectional view according to the second embodi- ment of the present invention. The clamping protrusion 25 is now located on the outer edge of the second component 21 and not on the first component 19. Furthermore, the outer edge of the first blocking part 29 is flattened due to the shape of bellow 39 forming the expansion reserve 27. Figs. 9 and 10 are a sectional view and a perspective view, respectively, of the resilient portion 1 1 and a second portion 13 according to the second embodiment of the present invention. As mentioned, both the resilient portion 1 1 and the second portion 13 are integrally formed out of silicone rubber tubing. In Fig. 9 it can be seen that the clamping protrusion 25 is now directed towards second portion 13 and that the second blocking part 31 comprises a sealing ring 41 on the circular surface. This thin sealing ring 41 is pressed against the first blocking part 29 around the circular opening of first cavity 20 of second component 21. Due to the mentioned differences in material and due to the shape of the sealing ring 41 the sealing or blocking function of valve 3 is improved. The sealing ring 41 can also be seen in Fig. 10 as well as the links 33 and channels 35 wherein the links 33 are responsible for holding the second blocking part 31 in place relative to the outer portions of the resilient portion 1 1.

Fig. 1 1 shows a sectional view of the third embodiment of the valve according to the invention. Considering the outside only, embodiments 2 and 3 are identical. However, the block- ing portion of valve 3 is designed differently in the third embodiment. In the third embodiment, the first locking part 29 comprises a central radial surface 43, an outer radial surface 45, links 33 between the central radial surface 43 and the outer radial surface 45 and channels 35. The corresponding surface of the second blocking part 31 is located around a cylindrical cavity in the resilient portion 1 1 so that pressing the resilient portion 1 1 due to the compressing force of the expansion reserve 27 onto the central radial service 43 of the first blocking part 29 which presents one end of the second component 21 will block the flow of fluid between the second tube and the first tube. The channels 35 for the flow of fluid and the blocking portion are therefore not integrated in the silicone rubber material of the resilient portion 1 1 as in the second embodiment but in the inner plastic construction of second component 21 . This makes the manufacturing of the silicone tube of resilient portion 1 1 simpler and thus easier to mold which reduces manufacturing costs. In comparison with the silicone rubber material the thermoplastic polymer material of the second component 21 is more easily moldable because no side action mold is needed. The engaging of the open end of the resilient portion 1 1 between the first component 19 and the second component 21 is identical to the one described with respect to the second embodiment, and therefore a detailed description is not repeated.

Figs. 12 and 13 show a perspective view and a sectional view, respectively, of the first component 19 used in the third embodiment of the present invention. The first component 19 comprises two mounting recesses 37 with parallel inner surfaces for the facilitation of mounting the valve assembly to a cassette to be used with a pump. The function of the first component 19 in the third embodiment is substantially identical to the one in the first embodiment; however, the dimensions of the clamping recess 23 and the contacting end faces between the first component 19 and the second component 21 are slightly different.

Figs. 14 and 15 show a perspective view and a sectional view, respectively, of the second component 21 as used in the third embodiment of the present invention. Here the elements of the blocking portion, i. e. the first blocking part, are viewable in a better way when compared with the image of Fig. 1 1.

Fig. 16 shows a sectional view of the resilient portion 1 1 integral with the second portion 13 as used in the third embodiment of the present invention. The clamping protrusion 23 is clearly visible extending towards the larger opening of the resilient portion 1 1 , and the second blocking part 31 comprises dimensions which fit with the size of the central radial sur- face 43 of the second component 21 forming the blocking portion of valve 3.

Fig. 17 shows a sectional view of a fourth embodiment of the valve according to the invention. The fourth embodiment represents a further development of the third embodiment with the following differences. The blocking portion, in particular the first blocking part 29 with the central radial surface 43 of second component 21 comprises a protrusion 47 in the fourth embodiment which extends into the cavity of the resilient portion 1 1 and the second portion 13, respectively. This has the technical advantage that bending the valve out of the central axis 28 will not cause the valve to open. The protrusion 47 can be better seen in Figs. 20 to 22 which will be described below. Another difference in comparison with the previously de- scribed embodiments is that resilient portion 1 1 and second portion 13 are no longer inte- grally formed. This is mainly due to the fact that the material of the resilient portion 1 1 (silicone rubber material) is more expensive to manufacture, in particular because of the high costs for the tools required for (liquid) injection molding. Therefore, resilient portion 1 1 and second portion 13 have been decoupled which can clearer be seen in Figs. 18 and 19 which are sectional views of both portions and only the resilient portion 1 1 , respectively. Both components, the resilient portion 1 1 and the second portion 13, can be manufactured as a two-component molding. As an alternative, for the material of the resilient portion 1 1 , a thermoplastic elastomer (TPE) may be used for certain fluids to be used with the valve according to the invention and polypropylene (PP) may be used for the second portion 13 which is also called a tubing connector.

As can be seen from Figs. 17 to 19 the second blocking part 31 is a relatively thin circular area with an opening for the flow of fluid therethrough. The surface close to the opening in the direction towards the bellow 39 of the resilient portion 1 1 is the area that in fact works as the blocking area, on which a sealing ring 41 may be included to improve the blocking function.

Figs. 20 and 21 show a perspective view and a sectional view, respectively, of the second component 21 according to the fourth embodiment of the present invention. The shown second component 21 is in principle identical with the one shown in Figs. 14 and 15, respectively, for the third embodiment, the only difference is the protrusion 47 extending from the central radial surface 43. It can be seen that the central radial surface is not in the same plane as the remaining surfaces of the first blocking part 29, i. e. the radial surfaces of the links 33 and the outer radial surface 45. The planes are still parallel but the plane of the central radial surface protrudes slightly. This is due to the fact that the hard material of the second component 21 in the area of the central radial surface 43 mates with the soft material of the second blocking part of the resilient portion 1 1 and therefore is pressed into the softer material. As mentioned before, the protrusion 47 has the technical advantage that when the entire valve 3 is bent in the area of the resilient portion, the locking function will not be negatively influenced meaning that the engagement of the central radial surface 43 with the second blocking part of the resilient portion 1 1 is kept intact. Channels around the protrusion 47 ensure that the flow rate of fluid is not significantly reduced. Fig. 22 shows a sectional view of the resilient portion and a perspective view of the second component 21 together in one drawing such that the blocking function becomes clearer. In contrast to Fig. 17, the valve 3 of Fig. 22 is in the closed position, i. e. the central radial surface 43 engages the corresponding surface of the second blocking part 31 of resilient por- tion 1 1. Bellow 39 is therefore in the relaxed position.

Fig. 23 shows an enteral feeding or infusion pump 49 known in the art. Pump 49 comprises a peristaltic drive mechanism 51 around which a silicon tubing 52 is mounted. The silicon tubing 52 is attached to the pump at a plurality of recesses 53 with at least one flange 55 and led around the peristaltic drive mechanism in an angle of approximately 180°. Fig. 23 is shown to demonstrate that the valve according to the invention may be used with such an infusion or enteral feeding pump if the fifth embodiment of the valve according to the invention is used. Figs. 24 and 25 show a sectional view and a perspective view, respectively, of a fifth embodiment of a valve 3 according to the invention. The fifth embodiment is from a functional perspective very similar to the fourth embodiment described earlier, the only difference is that the first component 19 comprises a flange 55 to be mounted to the recess 53 of the pump 49. It should be noted that different forms of flanges 55 are also possible which would render the valve according to the invention compatible with other pumps available in the market.

Fig. 26 is a sectional view of a sixth embodiment of the valve according to the invention. This embodiment has been designed to further reduce the manufacturing costs by integrat- ing the first component 19 and the second component 21 into only one piece, the first portion 9. First portion 9 therefore comprises the first blocking part 29 with the respective links 33 and channels 35 as well as protrusion 47 described above. Having only one component instead of a first component and a second component means that the clamping or attaching of the resilient portion 1 1 to the first portion 9 must be solved in a different technical way. In the sixth embodiment, the clamping recess of first portion 9 is oriented radially but not axi- ally as described with reference to the previous embodiments. Consequently, resilient portion 1 1 comprises a clamping protrusion 25 which is configured to mate with clamping recess 23 in first portion 9. A further difference differentiating the sixth embodiment from the fourth embodiment with respect to the resilient portion 11 and the second portion 13 is that the second blocking part 31 is part of the second portion 13, and not of the resilient portion 1 1. Through this modification further cost savings may be achieved because the complexity of the tool for the resil- ient portion 1 1 decreases due to the lacking of second blocking part 31. Of course, it must be ensured that the blocking function, i. e. the firm engagement between the first blocking part 29 and the second blocking part 31 fulfils all set requirements, in particular there should be a soft material pressing against a hard material to guarantee a sufficient blocking function. The sixth embodiment solves this by using soft polyvinyl chloride (PVC) for the second portion 13 and thus also for the second blocking part 31. The material of the resilient portion 1 1 and thus the expansion reserve 27 and bellow 39 remains silicone rubber material.

Fig. 27 shows a detail in sectional view of the sixth embodiment of the valve according to the invention. Here, it can be seen that the resilient portion 1 1 and the second portion 13 are made of two different materials wherein the function of the second blocking part 31 is performed by the end surface of second portion 13. Further, it can be seen that resilient portion 1 1 and second portion 13 are in engagement with each other through a corresponding recess / protrusion combination. Figs. 28 and 29 show a perspective view and a sectional view, respectively of first portion 9 according to the sixth embodiment of the present invention. The details of the elements of first portion 9 have been described with reference to the previous embodiments and are therefore not repeated at this point. It must be noted that in all shown embodiments the resilient portion 1 1 including the expansion reserve 17 (or bellow 39) is designed such that a certain pretension is applied to the first and second blocking portions. In other words, in the closed position of valve 3 the material and the dimensions of the corresponding elements ensure a proper engagement of the blocking parts such that the block of flow of fluid is guaranteed.

With the object of the present invention a valve for engaging with a tube to be used in an enteral feeding or infusion pump has been provided which comprises a full anti free flow functionality, i. e. which ensures a closed state when assembled in a cassette of a enteral feeding or infusion pump, which on the other side allows liquids to be pumped through when mounted on a pump, which is of a simple construction thus ensuring low manufacturing costs, small in size, and which is compatible with the majority of existing pump devices.

Claims

Valve (3) for engaging with a tube to be used in an enteral feeding or infusion pump adapted to feed a fluid to a patient, the valve (3) comprising: a first portion (9) having a first cavity (20) and adapted to be connected to a first tube, a second portion (13) having a second cavity (17) and adapted to be connected to a second tube (7), a resilient portion (1 1) having a cavity connecting the first portion (9) and the second portion (13), and a blocking portion blocking the flow of fluid between the first tube and the second tube (7) when the valve (3) is in the closed position, wherein the resilient portion (1 1 ) comprises an expansion reserve (27) adapted to release the flow of fluid between the first tube and the second tube (7) when the first (9) and the second (13) portions are moved away from each other in opposite directions to bring the valve (3) into the open position.

Valve (3) according to claim 1 , characterized in that the first portion (9), the second portion (13) and the resilient portion (1 1 ) are rotationally symmetric and aligned along a common axis (28).

Valve (3) according to claim 1 or 2, characterized in that the expansion reserve (27) includes at least one bellow (39).

Valve (3) according to one of the previous claims, characterized in that the blocking portion comprises a first blocking part (29) and a second blocking part (31 ) engaging with each other when the valve (3) is in the closed position.

Valve (3) according to claim 4, characterized in that the first blocking part (29) is formed of relatively hard thermoplastic polymer material such as polypropylene (PP), polyvinyl chloride (PVC), and polyethylene (PE), and that the second blocking part (31 ) is formed of relatively soft thermoplastic elastomer (TPE) or silicone rubber material.

6. Valve (3) according to claims 4 or 5, characterized in that the first blocking part (29) comprises a central radial surface (43) and an outer radial surface (45) connected by a plurality of links (33) so as to form a plurality of channels (35), wherein the central radial surface (43) is configured to engage with a ring surface (41 ) of the second blocking part (31 ).

7. Valve (3) according to claim 6, characterized in that the central radial surface (43) includes a protrusion (47) extending into a corresponding recess of the second blocking part (31 ).

8. Valve (3) according to one of claims 4 to 7, characterized in that the first blocking part (29) is integral with the first portion (9), the second portion (13) or the resilient portion (1 1 ).

9. Valve (3) according to one of the previous claims, characterized in that the first por- tion (9) comprises a first component (19) and a second component (21) configured to engage one end of the resilient portion (1 1 ) between each other.

10. Valve (3) according to one of the previous claims, characterized in that the resilient portion (1 1 ) and the second portion (13) are integrally formed.

1 1. Valve (3) according to one of the previous claims, characterized in that the resilient portion (1 1 ) is made of silicone rubber or of a thermoplastic elastomer (TPE).

12. Valve (3) according to one of the previous claims, characterized in that the first por- tion (9) is made of thermoplastic polymer material.

13. Valve (3) according to one of the previous claims, characterized in that the first portion (9) comprises a recess (37) adapted to engage with a cassette of the enteral feeding or infusion pump.

14. Valve (3) according to one of the previous claims, characterized in that the first portion (9) comprises a flange (55) adapted to attach the valve (3) to a corresponding recess (53) in a pump (49).

15. Use of a valve (3) according to any of the previous claims in an enteral feeding or infusion pump.