Patent Application
20150231385
The invention relates to a one-way valve device, in particular a low-pressure check valve for use in infusion equipment, preferably for gravitational infusion and pump infusion, consisting of a housing with an inlet line and an outlet line, and with at least one seal lying in a pressure space.
Valve devices of the type in question are preferably used in infusion equipment in hospitals as a safeguard against running dry, wherein the valve devices are used to bring about an immediate stop to infusion when a reservoir filled with infusion liquid runs dry, so that no air gets into the infusion liquid and, toward the end of the delivery stream, into the venous system of a patient. A valve device for use in infusion equipment is known, for example, from the German published application DE 29 19 343 A1, which is equipped with a drip chamber and a float valve and which prevents entry of air into the infusion hose when the chamber runs dry. A further safeguard against running dry is known from the German published application DE 36 32 412 A1, in which a valve to protect against running dry is arranged upstream from a drip chamber in the direction of flow.
Moreover, DE 197 49 562 A1 discloses infusion equipment consisting of a highly suspended container for the infusion liquid and of a drip that can be connected to a throttle container by means of a mandrel, an adjustable roller clamp on a flexible inlet line beneath the drip, and an injection needle located at the line end. To prevent entry of air into the infusion liquid, in particular toward the end of the delivery of infusion liquid, a safeguard against running dry is provided upstream from the drip chamber in the direction of flow, or on the admission opening of the drip chamber, and the built-in valve thereof can sop the infusion liquid in a manner dependent on a prevailing static pressure of the through-flow. However, it has been found in practice that a safeguard against running dry as a function of the static pressure of the infusion liquid is not adequate to prevent entry of air, particularly if there is a possibility of the connections being mixed up through carelessness and, therefore, of the function of the safeguard valve no longer being guaranteed.
This is particularly dangerous if air gets into the system and advances into the patient's veins, where it can lead to an embolism. It is therefore important that the infusion liquid does not entrain any air which leads to the aforementioned disadvantage. A particular disadvantage is that, if there is a static overpressure at the outlet side, the previously known valve cannot prevent entry of air into the system.
Finally, DE 102 19 994 A1 discloses a one-way valve device which tackles the disadvantages of the aforementioned prior art and proposes a valve device in which the entry of air into the system of the infusion equipment can be prevented with greater reliability. For this purpose, provision is made that the through-flow is interrupted when a static underpressure arises on the inlet and/or outlet line or when there is an overpressure on the outlet line. For the purpose of sealing the inlet line and the outlet line, a seal is provided which, inside a pressure space, bears alternately on one side on a first sealing ring lip and on the opposite side on a second sealing ring lip, in each case with tensioning. The seals obtained in this way provide sealing of the sealing ring lips, which are operatively connected to the inlet line and outlet line and, in the event of an underpressure, permit sealing with respect to the sealing ring lips. On account of the alternate sealing of the sealing ring lips by at least one seal, it is ensured that, in the event of an overpressure on the outlet line, a lifting of the seal takes place only on the sealing ring lip assigned to the outlet line, whereas by contrast the seal on the second sealing ring lip is pressed on account of the prevailing overpressure, thereby closing the inlet line. As an alternative to the use of a single pressure space with a seal located therein, that is to say a single membrane, it is also possible that two pressure chambers communicating via a connecting channel are formed, and a two-part seal is used.
A disadvantage of the proposed valve device is that the overall structure necessitates an unreasonable size and, particularly when the valve device is combined with an injection pump, this can reach such a considerable extent that there is a risk of the whole device accidentally being broken off.
As a result of the large dimensions, the costs of the valve device are also quite high. The costs of the special rubber membrane are also quite high, and, because of their complexity, the membrane or the valve device as a whole cannot easily be produced in an automated manufacturing method.
There is also the disadvantage that the opening pressure of the valve device is quite high and, for reasons relating to the appliance, cannot be reduced. The opening pressure is approximately the pressure of a 50 cm water column. Accordingly, the use of the valve device is suitable only in combination with infusion pumps, but not with those that operate by gravitational pressure.
The object of the invention is therefore to make available an improved one-way valve device that eliminates the aforementioned disadvantages of the prior art in DE 102 19 994 A1.
According to the invention, and in contrast to the valve device proposed in DE 102 19 994 A1, the object is achieved by the fact that, instead of two pressure chambers using the same membrane for the respective sealing and being arranged in the same plane, two pressure chambers are arranged one after the other in the flow direction of the medium that is to be administered. This means that the two pressure chambers lie with their bases over each other. This affords the advantage that the valve device can have much smaller dimensions, particularly as regards its width as seen in relation to the flow direction. Therefore, the two pressure chambers do not lie in the same plane but in two different planes that are preferably parallel to each other. It is desirable that the two pressure chambers at least partially overlap each other in a plan view. Plan view signifies the flow direction, or the direction from one base side of the cylinder of the housing to the other side, or from the first side of the housing to its second side.
For example, the valve device can thus have a cylindrical shape, wherein the first pressure chamber is arranged in the upper area of the cylinder (if the cylinder is standing on an end face) and the second pressure chamber in the lower area.
By arranging the two pressure chambers in tandem, the opening pressure can also be much better adjusted and can reach lower values, such that, for example, infusion equipment with gravitational pressure can be used in combination with the proposed valve device.
In addition, there is also the advantage that the proposed valve device can be more easily used with needle-free valves as are offered presently on the market.
Although more components are needed by comparison with the prior art, these components can be produced and assembled more easily, such that the production costs as a whole can be reduced. Moreover, the time needed for production can be reduced, since the components generally are of less complexity.
In the valve device according to the invention, it is necessary that at least two seals or membranes are used. According to the invention, these are likewise arranged in tandem with respect to the flow direction of the medium that is to be administered. Therefore, the two seals or membranes do not lie in the same plane but instead in two different planes that are preferably parallel to each other.
It is desirable that the two seals at least partially overlap each other in the plan view.
As regards its function, however, the valve device according to the invention corresponds in other respects to the device known from DE 102 19 994 A1.
It is further proposed that the housing of the valve device according to the invention has a main part and a housing attachment. These two parts are intended to be joined and closed so as to be leaktight. This can be done, for example, by means of ultrasonic welding when connecting the two parts to each other. The housing attachment preferably has an inlet line into the valve device, and the main part has an outlet line from the valve device for the medium that is to be administered. A first sealing ring lip is operatively connected to the inlet line, and a second sealing ring lip is operatively connected to the outlet line.
The assembled parts of the housing preferably form a hollow space in which the seals or membranes are arranged. Moreover, an inner valve part can be arranged in the hollow space, preferably between the two seals or membranes, and can serve for securing the seals or membranes and/or for providing a seal together with the seals or membranes and/or for conveying the medium that is to be administered through the valve device.
The first and second pressure chambers are also arranged in the aforementioned recess between the main part and the housing attachment of the housing. The walls of the first and second pressure chambers are therefore defined by the inner part, and the first and/or second seal, and they can preferably also be defined by the main part or the housing attachment.
The first seal is preferably part of a first valve disk, and the second seal is preferably part of a second valve disk. The valve disks and/or the seals or membranes can have through-holes.
The first valve disk is preferably clamped between the inner housing part and the housing attachment in such a way that the seal or membrane bears with pretensioning against the housing attachment. Alternatively, the seal or membrane can also bear with pretensioning against the valve disk.
The second valve disk is preferably clamped between the inner housing part and the main part in such a way that the seal or membrane bears with pretensioning against the inner face of the second valve disk and/or against the main part.
Thus, the same technical effects as in the prior art in DE 102 19 994 A1 can be achieved, namely that the through-flow is interrupted when a static underpressure arises on the inlet line and/or outlet line or when there is an overpressure on the outlet line. A static underpressure on the inlet line can arise, for example, when a reservoir containing the infusion liquid, or the medium to be administered, has run dry, when an infusion pump is operating incorrectly or when air has entered the system. An overpressure on the outlet line can arise, for example, upon temporary closure of the arm veins of the patient, when a medicament pump is additionally attached on the output side. An overpressure would lead to the medicament being pumped into the gravitational infusion system.
However, the valve device according to the invention ensures that, in the aforementioned cases, further transport of the infusion liquid is reliably stopped and, consequently, the entry of air-enriched infusion liquid into the veins is prevented. In addition, the one-way valve ensures that, when an overpressure prevails on account of an infusion pump or medicament pump, the valve closes on the output side and, consequently, the medicament does not get into the infusion system, as a result of which a transient overdose is prevented.
For sealing purposes, sealing ring lips or sealing lips are preferably used in addition to the seals or membranes. They can be arranged on the parts of the housing, that is to say, for example, on the housing attachment and/or on the main part. The seals or membranes preferably bear with pretensioning against the sealing ring lips.
Alternatively, it is conceivable that the sealing ring lips are arranged on the seals or membranes. They can be arranged such that the seals or membranes press with the sealing ring lips against the parts of the housing, that is to say the first seal or membrane with its sealing ring lip against the housing attachment and/or the second seal or membrane with its sealing ring lip against the main part.
This embodiment has the advantage that the seals or membranes are therefore slightly stiffer. An even lower opening pressure of the valve device can thereby be achieved.
The invention is explained in more detail below with reference to the figures.
In the figures:
The one-way valve device 1 according to the invention shown in
Two valve disks 51, 52, with an inner housing part 53 lying between them, are arranged inside the housing 2, 3, that is to say substantially within the receiving area inside the main part 2. The first valve disk 51, seen in the flow direction, has at least one seal or membrane 61. The inner housing part 53 is arranged downstream from this in the flow direction. Downstream from the inner housing part 53 is the second sealing disk 52, which has at least one seal or membrane 62.
The sealing ring lip 9 preferably surrounds an aperture 7 inside the housing attachment 3, which is part of the inlet line 5. The sealing ring lips are preferably designed in principle in an annular shape. This annular shape preferably surrounds the aperture 7 of the inlet line and the opening 16 of the outlet line.
In the same way, sealing is provided by the second valve disk 52 and/or by the second seal or membrane 62 and a second sealing ring lip 13, which is arranged on the main part 2 of the housing. The sealing ring lip 13 surrounds an opening 16, which is part of the outlet line 14. The valve disk 52 and the seal 62 are pressed again with pretensioning onto the sealing ring lip 13. The valve disk 52 thus sits, in a manner corresponding to the first valve disk 51, with an interference fit between the inner housing part 53 and the main part 2 of the housing. The second valve disk 52 thus provides sealing when the pressure in all areas of the valve device is equalized (i.e. when not in operation, for example) and when there is an underpressure in the outlet line 14, which is located inside the main part 2 of the housing.
In this embodiment of the invention, the relevant reference pressure is made available via a continuous slit 18 between the housing parts 2 and 3 and a channel 19 in the inner valve part 53. In the present invention, this pressure space 12 is divided into a pressure chamber 12a below the membrane 61 and a pressure chamber 12b below the membrane 62. Both pressure chambers 12a, 12b form the pressure space and are connected to each other and to the outside air as described. The first pressure chamber 12a, which is located inside the inner housing part 53, downstream from the first valve disk 51 in relation to the flow direction, is additionally designed such that, when an overpressure is present therein, the seal or membrane 61 is pressed onto the sealing ring lip 9 and thus closes. Thus, for example, an overpressure on the outlet line 14, as can occur for example when the arm veins of the patient are temporarily closed, cannot lead to the supplied medium flowing back again through the valve device counter to the flow direction.
According to the invention, the housing opening 18 is obtained in a particularly simple way if the ultrasonic welding between the main part 2 and the housing attachment 3 is not carried out over the entire circumference of the housing and, instead, sectors are omitted. In this area, a space then remains between the two housing parts 2 and 3, which space forms this housing opening 18. It is particularly preferable if the inner housing part 53 is pressed with an interference fit between a circular plane area 2a of the main part 2 and a similarly plane area 3a of the housing attachment 3. In this way, it is at the same time ensured that the air-carrying connection between the housing opening 18 and the pressure chamber 12 is sealed off in relation to the fluid-carrying parts of the valve. For this purpose, it is particularly preferable for the inner housing part 53 to be made of a thermoplastic elastomer with a Shore hardness of 70 to 80 A.
Moreover, a perfect centering of the inner housing part 53 in the main part 2 of the housing, and therefore also in the housing attachment 3, can be achieved if the inner housing part 53 has, on its outer edges between end face and circumferential face, a bevel 53a, which corresponds to a matching bevel 2b at the transition between the perpendicular housing wall of the main part 2 and the circular plane surface 2a of the main part 2. In this way, when the housing parts 2 and 3 are joined together, the inner housing part 53, inserted beforehand between these parts, is optimally centered automatically and, therefore, a correct position of the valve lips on their mating surfaces is also achieved.
The exploded view in
A further possible use lies in injection pumps and infusion applications. The valve device according to the invention is in fact designed such that, even with a very low opening pressure (generally between 1.5 and 5 Psi or between 104 and 345 millibar) and a very low infusion volume with an infusion speed of 0.2 to 1 mm3 per hour, it permits a constant through-flow, prevents backward flow of the medium and can prevent runoff during exchange of the supply containers or injection devices (pumps, etc.) and can prevent air from being fed into the veins of the patient.
A further area of use of the valve device according to the invention lies in infusion systems that operate with gravitational pressure. The one-way valve device according to the invention can in fact be designed such that it already opens at a pressure of a water column of 15 cm.
Finally, the use of peristaltic pump infusion is also possible in the valve device according to the invention. In this case, however, it is important that the valve device is arranged directly downstream from the pump in the flow direction and not at the distal end (for example of a hose arranged between the pump and the valve device). In the latter case, the required liquid column downstream from the valve device, which is needed for the correct functioning of the anti-siphon valve, would be absent. It would then be possible for air to enter the infusion equipment.
In the direction of flow, this pressure chamber 12a is delimited by an abutment face for the membrane 61. This is formed by four circle sectors 30, which each rise outward in a concave curvature and thus prevent overloading of the membrane, since they support this membrane 61 in the curved state.
To be able nonetheless to subject the membrane 61 to outside air pressure, the sectors 30 are each separated by rectangular channels 32, which become deeper toward the outside.
The structure of this further embodiment of the one-way valve 1′ according to the invention is explained in more detail below with reference to
As can be seen in
Of course, this embodiment too can be modified in such a way that the membranes 61′, 62′ are each smooth, and corresponding lips 9′, 13′ are formed on the valve seats, as is shown in
Moreover,
In the embodiment according to
Here too, as in the embodiment according to
The configuration of the other parts of the device according to the invention corresponds to the eccentric arrangement of
The cross-sectional view in
In this embodiment, however, the configuration has once again been chosen in which the sealing lips 71′″ and 72′″ are arranged on the respective membranes 61″ and 62′″, respectively, and not on the respective valve seat, which accordingly has a plane shape in this case.
This list of documents cited by the applicant has been generated automatically and is included solely to better inform the reader. The list is not part of the German patent or utility model application. The German Patent and Trademark Office accepts no liability for any errors or omissions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2012 007 884.4 | Aug 2012 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2013/001805 | 8/20/2013 | WO | 00 |
