WO2018009142A1

WO2018009142A1 - Infusion pump

Info

Publication number: WO2018009142A1
Application number: PCT/SE2017/050768
Authority: WO
Inventors: Morgan Andersson
Original assignee: Carucell Ab
Priority date: 2016-07-08
Filing date: 2017-07-07
Publication date: 2018-01-11

Abstract

An infusion pump is disclosed, which comprises a housing, a chamber located in the housing, an outlet, an outlet valve between the chamber and the outlet, an inlet,and an inlet valve between the inlet and the chamber. At least one of the outlet valve and the inlet valve comprises a spherical valve member, a valve seat member, and a spring member arranged to bias the spherical valve member towards a valve seat of the valve seat member.A method for providing the infusion pump is also disclosed.

Description

Infusion Pump

Field of the Invention

This invention pertains in general to the field of infusion pumps, such as ambulatory infusion pumps that may be devised for application in micro infusion therapies. More particularly, the invention relates to an infusion pump that comprises a housing, a chamber located in the housing, an outlet, an outlet valve between the chamber and the outlet, an inlet, and an inlet valve between the inlet and the chamber. At least one of the outlet valve and the inlet valve comprises a spherical valve member, a valve seat member, and a spring member arranged to bias the spherical valve member towards a valve seat of the valve seat member. A method for providing the infusion pump is also disclosed.

Background of the Invention

Ambulatory infusion pumps may be used for infusion therapy of liquid medicaments or nutrients, such as for diabetes care or pain management. The devices are designed for continuous delivery of small precise amounts of the liquid. The ambulatory infusion pumps are operated by interacting with the infusion pump via a user interface including a display and buttons for manipulating the infusion pump. The devices are normally battery powered and include various electronics, and a pumping unit. The liquid is contained in a reservoir. Since the user normally carries the device around the clock, it is desired that the device is small and light. Many times that is not the case due to the type of pump unit used and the requirements for a user interface, which restricts the possibilities to design a device that is convenient to carry and simple to operate. The design is dictated by the technology rather than user needs. However, due to the small amounts of liquid being administrated, designing a reliable pump unit that that does not dictate the design options for the device is challenging.

One example of an ambulatory infusion pump is the insulin pump. This micro infusion pump has evolved from a manual syringe. Most insulin pumps available on the marked are simply an atomized syringe comprising a cylindrical container and a piston. Movement of the piston in small increments relative the cylindrical container is effected by a small step motor in order to deliver a predefined amount of insulin at predetermined time intervals, which simulates a "continuous" delivery of insulin. The amount of insulin delivered in each incremental movement of the piston can be about 0.00025-0.00050 ml or 0.25-0.50 mm3.

The piston pumps are relatively bulky. The housing for the pump needs space for the full stroke of the piston, which is essentially twice the entire length of the cylindrical container for the medicament. The cylindrical container has only one outlet, such that the container needs to be filled or replaced after a single stroke of the piston. Devices containing this type of technology tend to be bulky, square and inconvenient for the user. The devices are designed around the technology, including the pump unit, battery and display, making them fairly bulky and inconvenient for the user to carry. The pump unit offers few options to design a user-friendlier device.

Another example of an infusion pump is for administration of a medicament for pain management or for nutrients. Such pumps may deliver medication or nutrients from either a cassette type of tube arrangement or from an administration type of tube arrangement. Such pumps include a reusable control module detachably coupled to a pressure plate at a top surface of a disposable fluid reservoir cassette. Fluid is pumped from the cassette by the reusable control module when the cassette is coupled to the control module. These types of pumps tend to be less precise, making them unsuitable for administration of minute amounts of liquid, such as insulin.

Still other examples of infusion pumps comprise a flow material reservoir wherein the liquid is pressurized. The liquid is contained in a compressible container or bag, and air around the container or bag is pressurized. These devices require complex and expensive sensors to measure the volume of the flow material reservoir and/or the volume of flow material dispersed from the infusion pump.

Hence, an improved infusion pump, and components useable for such an improved infusion pump, would be advantageous and in particular allowing for improved robustness, increased flexibility, cost-effectiveness, and/or reduced complexity would be advantageous.

Summary of the Invention

Accordingly, embodiments of the present invention preferably seek to mitigate, alleviate or eliminate one or more deficiencies, disadvantages or issues in the art, such as the above-identified, singly or in any combination by providing an infusion pump, and a method for providing such an infusion pump, according to the appended patent claims.

Embodiments includes an infusion pump, comprising a housing, a chamber located in the housing, an outlet, an outlet valve between the chamber and the outlet, an inlet, and an inlet valve between the inlet and the chamber. At least one of the outlet valve and the inlet valve comprises a spherical valve member, a valve seat member, and a spring member arranged to bias the spherical valve member towards a valve seat of the valve seat member.

The spring member may comprise a disc spring. Additionally or alternatively, the spring member may comprise a rim arranged at least partially around a circumference of the spherical valve member. The rim may be arranged completely around the circumference of the spherical valve member. In some embodiments, the rim may form a seal between the valve seat member and the housing.

A spring element of the spring member may be formed by at least one slit in the center of the spring member. Additionally or alternatively, the spring element and the rim may be formed as a single component. The rim may be ring-shaped. The spherical valve member may be arranged at least partially between the valve seat member and the rim. A pressure component of the spring member, which may form a seat for the spherical valve member, may be connected to the rim via a spring element and arranged in abutment with the spherical valve member and may be biased towards and moveable relative the valve seat.

The rim may be arranged at a ledge within a recess of the housing or within the valve seat member. In some embodiments, a height of the ledge may be lower than a thickness of the rim in an uncompressed state. The rim may be compressed between the valve seat member and the housing when assembled.

The housing may include a first housing unit and a second housing unit. The chamber may be located in the first housing unit. The spherical valve member and the valve seat member may be arranged between the first housing unit and the second housing unit. The first housing unit and the second housing unit may be joined to form the housing.

The valve seat member and at least one of the first housing unit and the second housing unit may be made of different materials.

The valve seat member may be made of a metallic material. Additionally or alternatively, the valve seat member may comprise the valve seat. The valve seat may have a radius

corresponding to a radius of the spherical valve member. Additionally or alternatively, the first housing unit may comprise a recess for receiving the valve seat member. The first housing unit may be made of a non-metallic material.

The first housing unit and the second housing unit may be made of the same material and together form at least one space for enclosing at least one of the outlet valve and the inlet valve. The the valve seat member may comprises a recess, in which the spherical valve member is at least partially arranged.

Some embodiments comprise a reservoir for a liquid medicament or a nutrient arranged in fluid communication with the inlet of the infusion pump according to embodiments of the infusion pump.

Some embodiments comprise a pre-assembled valve. The valve may be used as at least one of the inlet valve and the outlet valve of embodiments of the infusion pump of embodiments. The pre-assembled valve may comprise a valve seat member, a disc-shaped spring member, and a spherical valve member arranged at least partially between the valve seat member and the discshaped spring member.

Some embodiments comprise a method for providing an infusion pump. The method comprises providing a housing comprising a chamber, an outlet, and an inlet, providing at least one of an outlet valve comprising a first spherical valve member and a first valve seat member, which comprises a first valve seat, and an inlet valve comprising a second spherical valve member and a second valve seat member, which comprises a second valve seat, providing at least one spring member, arranging at least one of the outlet valve between the chamber and the outlet, and the inlet valve between the chamber and the inlet; and biasing at least one of the first spherical valve member towards the first valve seat, and the second spherical valve member towards the second valve seat, using said at least one spring member.

Further embodiments of the invention are defined in the dependent claims.

Embodiments of the invention provide a less complex and more flexible infusion pump that accurately can deliver minute volumes of liquid. Embodiments provide for precision that is sufficient for use as an insulin pump. Embodiments provide an insulin pump with a chamber that is smaller than the reservoir in which the liquid to be administered is contained. Embodiments have an inlet valve and an outlet valve to the chamber, which provide for pressurizing the liquid in the chamber but not in the reservoir. Instead, the design allows for using the same components of the pump for refilling the chamber with liquid from the reservoir and for pressurizing the liquid in the chamber. This allows for reduced complexity. Also, the chamber and the reservoir can be separated, which offers increased flexibility to design a user-friendly ambulatory infusion pump that is less dependent on the technology. The chamber can be made much smaller with a fixed shape, whereas the reservoir from which the liquid is drawn can have an arbitrary shape, such as adapted to the exterior chassis of the device. The chassis can in turn be designed with the user needs in mind rather than being dictated by the pump technology. The device can for example be designed for different user groups, such as for men, women, kids etc. with different designs of the chassis where the reservoirs for different user groups have different shapes in order to accommodate requirements on the chassis design. Yet, the design of the infusion pump unit with the chamber may be fixed, but due to its small size it does not impair the flexibility and design options for the chassis. Furthermore, embodiments provide for reduced complexity that provide for overall simplified production with associated reduced manufacturing costs. Embodiments of the invention contribute to make the infusion pump precise for delivery of minute amounts of liquid, such as various aspects of valves and/or disc springs for an inlet and/or an outlet to/from the chamber. Such embodiments may form separate inventions, but each contribute and combine to the reduced complexity and increased flexibility of the infusion pump of the present invention. For example, the valve is particularly useful for an infusion pump, wherein minute amounts of a liquid are delivered. The chamber of the pump for pressurizing the liquid can be made smaller than is previously known since using the valve allows for refilling the chamber. A smaller chamber allows for a smaller diameter of a piston for pressurizing the liquid, which in turn means that the accuracy of the infusion pump is improved. The piston can simply travel a longer distance for each delivery of liquid compared to previously know infusion pumps with a single stroke, which must have a larger diameter to deliver the same amount. A longer travel is easier to control, allowing for improved accuracy. It should be emphasized that the term "comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Brief Description of the Drawings

These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which

Fig. 1 is a cross-sectional view of an embodiment of the infusion pump;

Fig. 2 is a cross-sectional view of an embodiment of the valve;

Fig. 3 is a cross-sectional view of an embodiment of an inlet valve and an outlet valve each arranged in a recesses of the first housing unit and the second housing unit;

Fig. 4 is an exploded view of an embodiment of the infusion pump:

Fig. 5 is a perspective view of an embodiment of a spring member;

Fig. 6 is a top view of an embodiment of a spring member;

Fig. 7 is a cross-sectional view of a valve with an inlet connected to a reservoir;

Fig. 8a is a cross sectional view of a pre-assembled valve; and

Fig. 8b is a perspective view of a pre-assembled valve.

Description of Embodiments

Specific embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

The following description focuses on embodiments of the present invention applicable as an ambulatory infusion pump, such as an insulin pump. However, it will be appreciated that the invention is not limited to this application but may be applied for administration of other liquid medicaments, liquid pain management and/or nutrient. It is particularly useful for incremental administration of minute amounts of liquid, such as about 0.00010-00050 ml in each step.

Fig. 1 illustrates components of embodiments of an infusion pump unit, which will be referred to as an infusion pump in the following. The infusion pump comprises a housing 1. In the embodiment of Fig. 1 , the housing comprises a first housing unit 2 and a second housing unit 3. A chamber 4 is located at least partially in the first housing unit 2. The housing 1 includes an outlet 5, and an inlet 6. An outlet valve 7 may be arranged between the chamber 4 and the outlet 5. An inlet valve 8 may be arranged between the inlet 6 and the chamber 4.

Fig. 2 illustrates a valve 10, which may be used as the outlet valve 7 and/or the inlet valve 8. The valve 10 comprises a spherical valve member 11, and a valve seat member 12. The valve seat member 12 has a first recess 13. The first recess 13 may extend from a first end of the valve seat member 12, which preferably is cylindrical, towards an opposing second end. The first recess 13 may have a depth that is slightly smaller than a diameter of the spherical valve member 11 , which may be used for biasing the spherical valve member 11 towards a valve seat 14 of the valve seat member 12, as will be discussed below. In other embodiments, such as illustrated in Figs. 8a-8b, the spherical valve member 11 is fully contained in the valve seat member 12. The first recess 13 has a diameter slightly larger than the diameter of the spherical valve member 11. The spherical valve member 11 can freely move within the first recess 13 in the axial direction of the valve 10. However, the spherical valve member 11 can substantially not move within the first recess 13 in the radial direction of the valve 10. Hence, the spherical valve member 11 may be centered within the first recess 13. A slight space between the recess 13 and the spherical valve member 11 allows liquid to pass when pressurized, whereby the spherical valve member 11 moves in the axial direction of the valve to provide clearance from the valve seat 14. The valve seat member 12 has a second recess 15 from the second end, opposing the first end, of the valve seat member 12. The second recess 15 is preferably cylindrical. The second recess 15 is co-axial with the first recess 13 and has a diameter that is smaller than the diameter of the first recess 13. Hence, the valve seat 14 may have a diameter corresponding to a diameter of the spherical valve member 11 , which is not the maximum diameter of the spherical valve member 11. The first diameter may be in the range of 1.5-3 mm. The second diameter may be in the range of 1-2 mm.

The valve seat 14 is formed by an edge at the intersection of the first recess 13 and the second recess 15. The edge forms a surface against which a portion of the spherical valve member

11 may be seated in a closed position of the valve. The edge may have a chamfer. The chamfer may have a curvature, which is substantially complementary in shape to the curvature of an outer surface of the spherical valve member 11. Hence, the surface contact between the spherical valve member 11 and the valve seat 14 may be increased. An increased surface contact is useful in applications wherein the amount of liquid to administered is small and thus the compression in the chamber 4 for each increment of a piston 16 is low, such as for delivery of insulin. The increased surface contact improves the tightness of the valve, particularly in delivery of small amounts of liquid.

The spherical valve member 11 may be centered with the first recess 13 and the second recess 15, i.e. the center of the spherical valve member 11 is coaxial with the first recess 13 and the second recess 15 in the closed position. Since the diameter of the spherical valve member 11 is larger than the diameter of the second recess 15, a portion of the spherical valve member 11 extends into the second recess 15. The diameter and/or the length of the second recess 15 is/are dimensioned such that the portion of the spherical valve member 11 located therein does not reach the second end of the valve 10.

Returning to Fig. 1 , at least one of the outlet valve 7 and the inlet valve 8 comprises a spherical valve member 11 a, 11 b, and a valve seat member 12a, 12b arranged between the first housing unit 2 and the second housing unit 3. The valve 10 of Fig. 2 may be as used as the outlet valve 7 and/or the inlet valve 8, respectfully. Hence, for embodiments of the outlet valve 7 and/or the inlet valve 8, reference is made to the embodiments illustrated in Fig. 2. The piston 16 may be arranged in the chamber 4, such as illustrated in Fig. 2. The piston 16 may be a reciprocating piston 16 for pressuring liquid contained in the chamber 4. The piston 16 may have a circumferential recess 17 at its distal end for receiving a seal, such as an o-ring, for sealing between the chamber 4 and the piston 16. In a forward stroke, the piston pressurizes the liquid in the chamber 4 when moved towards the valves 7, 8, which closes the inlet valve 8 and/or opens the outlet valve 7. In a backward stroke the piston 16 is moved away from the valves 7, 8, which closes the outlet valve 7 and/or opens the inlet valve 8 and the chamber 4 is refilled with liquid. Hence, the inlet valve 8 and outlet valve 7 may co-operate to prevent pressurizing the reservoir for the liquid and a back-flow of liquid already delivered via the outlet. As such, the piston can be made smaller compared to the prior art, allowing for increased precision for delivering the same amount of liquid in a single step.

In some embodiments, the valve seat member 12 and at least one of the first housing unit 2 and the second housing unit 3 are made of different materials. For example, the first housing unit 2 and/or the second housing unit 3 may be made of a medical grade plastic material. The medical grade plastic material may have properties such that the housing unit may be sterilized, e.g. by hot or cold sterilization, and meet FDA (Federal Drug Administration) and USP (United States

Pharmacopeia) classifications, such as for containing liquid medical medicaments and nutrients. Such plastic materials are generally available as such and will not further discussed herein. The valve seat member 12 may be made of a metallic material, such as a surgical steel, for example austenitic 316 stainless steel or martensitic 440 or 420 stainless steel. Such metallic materials are generally available as such and will not further discussed herein. Providing the housing 1 and the valve seat member 12 in different materials provide for producing an infusion pump that is applicable for low pressures, and thus for delivery of small amounts of liquids in a single step, efficiently with high precision. Components of the infusion pump that are not critical for the accuracy of the infusion pump, such as the first housing unit 2, the second housing unit 3, and/or the piston 16 may be made in a material that can be produced in high volumes, such as by injection molding or casting, quickly and thus efficiently and at low cost. However, such materials and/or production processes may not have sufficient accuracy and/or be elastic making them unsuitable for achieving the accuracy required in certain applications, such as for administration of the amount of liquid involved e.g. for administration of insulin. The valve seat member 12 may be made of a material that is suitable for higher precision and/or producing using different technology than that of the housing 1. Such material may e.g. be a plastic material, for example the metallic material mentioned above. Plastic materials may be processed using one or several processing techniques, such as milling, turning, and/or punching, and using tools for successively increased accuracy of the components. Thereby, an interface between the valve seat member 12 and the spherical valve member 11 can be provided with higher accuracy compared to providing this interface directly in any of the housing units 2, 3 made of an elastic material. This is particularly useful in applications where the pressure in the chamber 4 for administrating the liquid is low. In applications where pressures in the chamber 4 are higher, the accuracy between the valve seat 14 and the spherical component is less critical. With high enough pressures, the valve seat 14 may be formed directly in the material of the housing 1 , even if that is an elastic material. The valve seat member 12 forms an intermediate component increasing the accuracy of the interface between the valve seat 14 and the spherical valve member 11. Accuracy in this context means that the surface of the valve seat 14 and the outer surface of the spherical valve member 11 should be sufficiently smooth that liquid may not pass the interface even when the piston 16 is moved a short distance within the chamber 4, such as in the range of 0,005- 0.015 mm in each in increment of the piston 16. The diameter of the chamber may be in the range of 4-8 mm. The maximum length of the chamber for containing liquid may be in the range of 4-20 mm. Hence, the chamber may as well as the infusion pump as such may be made compact.

Fig. 1 illustrates the first housing unit 2 and the second housing unit 3, which may be provided separate from the valve members 7, 8. The housing comprises at least one recess 20a, 20b that forms a space for receiving at least one valve member 7, 8. In this embodiment, a first recess 20a is provided for receiving the outlet valve member 7. A second recess 20b is provided for receiving the inlet valve 8. The first recess 20a and the second recess 20b may be sized such that the valves 7, 8 are received snugly therein in, for example in a press or friction fit. Hence, a seal is formed between the each recess 20a, 20b and the respective valve 7, 8. Thus, the recess 20a, 20b may have an inner dimension substantially corresponding to an outer dimension of the valve seat member 12a, 12b, whereby an outer surface of at least one of the outlet valve 7 and the inlet valve 8 is enclosed by each recess 20a, 20b.

In some embodiments, the space formed by the recess 20a, 20b is provided partially in the first housing unit 2 and partially in the second housing unit 3. This provides, e.g., for efficient assembly of the infusion pump. For example, about 1/3 to 2/3, such as about 1/2, of the recess may be formed in the first housing unit 2 and about 2/3 to 1/3, such as 1/2, of the recess may be formed in the second housing unit 3. Hence, the valve 7, 8 may first be arranged in the recess of the first housing unit 2, and then the second housing unit 3 is inserted into another recess at the distal end of the first housing unit 2, which is slightly larger in diameter than the recess in which the valve is arranged. Hence, the second housing unit 3 may form a plug, also illustrated in Fig. 4, received within the first housing unit 2 and may be positioned at least partially between the valve 7, 8 and a distal end of the housing 1 , such as the distal end of the first housing unit 2. This provides for providing a seal between the first housing unit 2 and the second housing unit 3. Furthermore, the first housing unit 2 may be joined to the second housing unit 3 such that the valve 7, 8 is fully enclosed and the housing units 2, 3 may not disassemble and are liquid tight. Furthermore, a joint may be formed between the first housing unit 2 and the second housing unit 3, e.g. by an adhesive and/or by heat fusion of the material of the housing units 2, 3. At least one seal, such as an o-ring, may be provided in at least one recess of the valve seat member 12 and in abutment with the recess of the housing 1. In the illustrated embodiment, a first seal is arranged between the valve seat member 12 and the first housing member 2, and a second seal is provided between the valve seat member 12 and the second housing unit 3. An end of the second housing unit 3 is arranged between the seals in the axial direction of the housing 1 and within the first housing unit 2. Hence, efficient sealing is provided at the same time as the housing units 2, 3 and the valve 10 are easy to assemble.

In some embodiments, the first housing unit 2 and the second housing unit 3 are made of the same material. This provides for efficient production of these components, as described above, in a plastic material. It also provides for efficiently forming the joint, such as described above.

Fig. 3, illustrates embodiments of at least one spring member 30a, 30b that may be arranged within the housing 1 and in fluid communication with the chamber, such as between the first housing unit 2 and the second housing unit 3, illustrated e.g. also in Fig. 4. Each spring member 30a, 30b may be arranged to bias the spherical valve member 11 a, 11 b towards the valve seat 14 of each valve seat member 12a, 12b. A spring member 30a, 30b may be required when the amount of liquid that is administrated is small, i.e. when the length movement of the piston 16 is small for each increment, such as described above, whereby the pressure in the chamber 4 is equally small. Such biasing in not required for higher pressures and larger amounts of liquids being delivered each time of delivery.

In the embodiment of Fig. 3, the spring member 30a, 30b comprises a disc spring. The disc spring may be made of a plastic material, wherein the shape of the disc spring provides the required flexibility for biasing of the spherical valve member 11. In other embodiments, the spring member 30a, 30b is made of an elastic material, wherein the elastic properties of the spring member provide the flexibility of the spring element for the required biasing force.

Fig. 4 illustrates an embodiment of the infusion pump, including the housing with the first housing unit 2a. As illustrated, the first housing unit 2a may include a plurality of guide members at its proximal end for guiding the piston 16 during its reciprocating movement. The guide members extend substantially in the longitudinal axis of the first housing unit 2a. The piston 16a has mating protrusions extending substantially perpendicular to its longitudinal axis. Each protrusion is slidably received between a pair of guide members. Hence, guiding reciprocating movement of the piston 16 within the chamber along the longitudinal axis is provided for. An o-ring 50e is arranged

circumferentially around the piston 16a at the circumferential recess 17. The valve seat members 12a, 12b may be arranged within the housing, such as within the first housing unit 2. In this embodiment, each valve seat member 12a, 12b has a single circumferential recess for receiving a seal member 50a, 50c, such as an o-ring. The spherical valve members 11 a, 11 b may be arranged as described above. The spring members 30a, 30b may be arranged as described with regard to each of the embodiments described herein.

5 In the embodiment of Fig. 4, the valve seat member 12a, 12b is arranged at a recess of the first housing unit 2a. The second housing unit 3a, 3b forms a plug. In the illustrated embodiment, the recess of the first housing unit 2a for each valve seat member 12a, 12b has a uniform diameter. Hence, a first plug 3a is provided for valve seat member 12a, and a second plug 3b is provided for the second valve seat member 12b. The diameter of the plugs 3a, 3b may correspond to the o diameter of the valve seat members 12a, 12b, and may this be provided in the recesses between the valve seat members 12a, 12b and the distal end of the first housing unit 2a. Each plug 3a, 3b has a through hole that forms the inlet and the outlet, respectively. A seal member 50b, 50d, such as an o- ring, may be arranged in a circumferential recess in the plug 3a, 3b, which provides a seal between the first housing unit 2a, and the second housing unit 3a, 3b. The first plug 3a may be connected to a 5 fluid conduit, such as a hose of an infusion set. Hence, a fluid tight conduit is provided between the chamber and the outlet of the infusion pump. Similarly, the second plug 3b may be connected to or form part of a reservoir, e.g. as illustrated in Fig. 7. Hence a fluid tight conduit is provided between the reservoir and the chamber. The embodiment of Fig. 4 provides for a production process that is simplified by providing multiple components with uniform diameters, which also facilitates the o assembly process.

In other embodiments, the first and the second plug 3a, 3b are provided as a single unit, such as illustrated in Figs. 1 and 3, and arranged relative the first housing unit 2a. Each plug 3a, 3b may form the purpose to secure the valve seat members 12a, 12b within the first housing unit 2, 2a. Additionally or alternatively, each plug may provide a seal, e.g. using the seal member 50b, 50d, 5 between the first housing unit 2a and the second housing unit 3a, 3b. Hence, the tightness in the communication path from the inlet, via the chamber, to the outlet is further enhanced compared to having a single seal member only at the valve seat member 12a, 12b.

In still other embodiments, the housing only comprises the first housing unit 2, 2a. The valve seat members 12a, 12b may be arranged in a recess of the first housing unit, such as

0 described above, and provide the inlet and the outlet, respectively. The embodiment of Fig. 4 may also be combined with the other embodiments described herein, e.g. with regard to the spring members 30a, 30b, the seal members 50a-50d, and the first housing unit 2 and the second housing unit 3.

Figs. 5-6 illustrate embodiments of the spring member 130, 230 that comprises a rim 131 ,5 231 such as a circumferential rim. The rim 131, 231 may be arranged at least partially around the spherical valve member 11 , such as illustrated in Fig. 3. The spring member 130, 230 may have a pressure component 132, 232 that is arranged at the center of the spring member 130, 230, and that may be arranged in abutment with the spherical valve member 11. Hence, the pressure component 132, 232 may form a seat for the spherical valve member 11. The pressure component 132, 232 may abut the spherical valve member 11 coaxially with recesses 14, 15 of the valve seat member 12. A spring element 133, 233 connects the pressure component to the rim 131 , 231. The spring member 130, 230 may be generally disc shaped. Hence, the rim 131 , 231, the pressure component 132, 232, and the spring member 130, 230, may be provided in a single plane. As such, the spring member 131 , 230 may form a disc spring. Furthermore, the spring member 130, 230 may be formed from a single piece of material.

The spring member 130, 230 can be used for a valve 10 that is efficient to assemble while being useful for delivery of small amounts of liquid where the pressure provided by the piston 16 is not sufficient for providing a tight interface between the valve seat 14 and the spherical valve member 11. Particularly, the embodiments of Fig. 5-6 provide for applying a small pressure, such as a few hg, to the spherical valve member 11. Such small pressures are difficult to provide with a helical spring having subsequent turns in separate planes. Furthermore, a disc shaped spring member is easy to assemble with the valve seat member 12a, 12b, such as will be discussed below.

Figs. 5 and 6 illustrate embodiments where the rim 131 , 231 is arranged completely around a the spring member 131 , 231 , such as circumferentially around the spring member 131. Hence, it may also be provided circumferentially around an end of the valve seat component 12, such as is illustrated in Figs 8a-8b.

The rim 131 , 231 may form a seal between the valve seat member 12 and at least one of the first housing unit 2 and the second housing unit 3, such as when the rim 131, 231 is provided in an elastic material. For the outlet valve 7, the rim 131 , 231 may be arranged between the valve seat member 30a and the first housing unit 2. For the inlet valve 8, the rim 131 , 231 may be arranged between the valve seat member 30b and the second housing unit 3.

In the embodiments of Figs. 5, the spring element 133 is formed by at least one slit in an elastic element. The rim 131 may be provided circumferentially around the slit 133. The spring member 130 may be cylindrical, such as disc shaped. The elastic element may provide a seal, such as by the rim that encircles the at least one slit. The spring member 130 and the seal member may be formed as a single component. A central portion of the spring member 130 may form the pressure component 132. The pressure provided by the spring member 130 may e.g. be adjusted by the type of material of the spring element 133, the thickness of the material, and the number and/or shape of the at least one slit. The at least one slit may also be arranged for efficient flow of liquid passing the spherical valve member 11. In this embodiment, three slits are arranged in a triangular patter, with a piece of material separating the vertices of the triangle. Hence, the pressure component 132 is provided at the center of the triangular slit pattern.

In other embodiments, the at least one slit 133 is semi-circular. Alternatively or additionally, the slit may be straight extending from one side of the rim 131 to the other side of the rim 131. A straight slit allows for uniform pressure applied on a spherical valve member 11, which in turn provides for accuracy, particularly for delivery of small amounts of liquid. The number of and/or length/width of the slits provided may be selected depending on pressures, amount of liquid to be delivered, biasing force, the material of the spring member 30 etc. For example, the length may be in the range of 0.5-4 mm.

The embodiment of Fig. 6 illustrates a spring member in the form of a disc spring, which may be used for a valve of an infusion pump as discussed above. The disc spring comprises the rim 231, the spring element 233, and the pressure component 232 in the center of the disc spring. The pressure component 232 forms in this embodiment a circumferential seat. The spring element 233 is arranged around the circumferential seat, and the rim 231 , the spring element 233, and the circumferential seat are arranged in a single plane.

In the illustrated embodiment, the rim 231 is ring-shaped, the spring element 233 is spiral winding and extends from the rim 231 to the circumferential seat. The spring element 233 may have a plurality of circumferential turns. The thickness of the spring element 233 may be smaller than the width of each turn or the pattern such that the force exerted by the spring element 233 is substantially in the axial direction of the spring member 230. Furthermore, the circumferential seat is substantially circular. In this embodiment, the helically shaped spring element 233 has a first end connected to the rim 231, and a second free end. The last turn of the helically shaped spring element 233 forms the circumferential seat. In other embodiments, the circumferential seat is ring shaped, to which the second end of the spring element 233 is connected. Furthermore, in other embodiments, the rim 233 is formed by the last turn of a winding spring element. Hence, the entire spring element 233 may be winding in a single plane. At least a first turn may form the rim 231 , and a last turn may form the circumferential seat. Between the rim 231 and the circumferential seat 233, there may be distances between each turn at least when assembled in the valve, such that liquid is allowed to pass.

In the embodiment of Fig. 6, the spring element 233 is formed by at least one slit 234 extending from the rim 231 to a center section of the spring member 230. Again, the rim 231 may be provided circumferentially around the slit 234. The spring member 230 may be cylindrical, such as disc shaped. A central portion of the spring member 230 may form the pressure component 232. The pressure provided by the spring member 230 may e.g. be adjusted by the type of material of the spring member 230, the thickness of the material, and the number and/or shape of the at least one slit. The spring member 230 may be made of a metallic material, such as spring steel. The at least one slit 234 may also be arranged for efficient flow of liquid passing the spherical valve member 11. In this embodiment, the slit 234 is a spiral slit that forms a spiral spring element 233. The spring element may form one or several turns. In the illustrated embodiment, the spring element forms almost four turns, but may be in the range of 3-6 turns. The thickness of the spring member 230, the width of the spring element 233, and the shape of the spring element 233 may adjust the spring coefficient of the spring member 230. In the illustrated embodiment, the spring element 233 ends a distance in the radial direction from the center of the spring member 230. The last turn of the spring element 233 at the center of the spring member may form a substantially circular ridge that forms the pressure component 232. The ridge may have a diameter that is smaller than the maximum diameter of the spherical valve member 11 such that a pressure is applied around the spherical valve member 11 , as is illustrated in Fig. 8a. In other embodiments, the spring element 233 connects the rim 231 to the pressure component 232 in the form of a ring shaped element with a diameter that is smaller than the maximum diameter of the spherical valve member 11. In still other embodiments, the pressure component 232 is a plate arranged at the center of the spring member 230.

In other embodiments, the at least one slit 234 forms a meandering pattern between the rim 231 and the pressure component 232. In still other embodiments, the at least one slit 234 forms a cell structure between the rim 231 and the pressure component 232.

The spring member 130, 230 may be arranged to bias the spherical valve member 11 towards the valve seat 14. The pressure component 132, 232 may be biased towards the spherical valve member 11 by fixing the rim 131 , 231 in an appropriate position relative the spherical valve member. For example, the rim 131 , 232 may be arranged between the valve 11 and the first housing unit 2 and/or the second housing unit 3, and the pressure component to abut the spherical valve member 11 with a desired biasing force towards the valve seat 14. The at least one slit 133, 143 allows for movement of the spherical valve member 11 and for liquid to pass through the spring member 130, 230.

As is illustrated in Fig. 2, the rim 130 may be arranged at a ledge 40 of the recess 20a, 20b of the housing 1. For example, the ledge 40 may have a width that substantially corresponds to a width of the end of the valve seat member 12 at its first recess 13. The rim 131 , 231 may be fixed between the housing 1 and the valve seat member 12a, 12b by applying a pressure to the valve seat member 12a, 12b, such as by applying a pressure to the second housing unit 3 when assembled with the first housing unit 2. Hence, efficient assembly of the spring member 30 is provided for. Furthermore, the efficiency may be further improved by providing a seal with the spring member 30.

A height of the ledge 40 in the longitudinal direction of the valve seat member 11 may be shorter than a thickness of the rim 131. This ascertains that a pressure may be applied to the spring member 130, 230 when the valve seat member is assembled in the housing 1. Furthermore, if the spring member 130 is an elastic spring member the height of the ledge 40 may be shorter than the thickness of the rim 131 in an uncompressed state. In Fig. 2, the rim 131 is illustrated in its uncompressed state for illustration purposes such that the ledge 40 and the rim 131 overlap.

However, the rim would be compressed when the components are assembled. When the components are assembled, the valve seat member 11 is assembled in the housing 1 such that it abuts the ledge 40, whereby the rim 131 is compressed a predefined amount, which may provide a seal. At the same time, the pressure component 132 is biased towards the spherical valve member 11 providing a seal between the spherical valve member 11 and the valve seat 14. The same principle for providing biasing applies even if the spring member 130, 230 is provided in a non-elastic material, such as the embodiment of Fig. 6. For example, the valve seat member 12 may compress the rim 31 when the second housing unit 3 is arranged relative the first housing unit 2 in an assembled state.

As can be seen in Figs. 3 and 4, at least one seal member 50a, 50b may be provided between the first housing unit 2, 2a and the valve seat member 12a of the outlet valve 7.

Correspondingly, at least one seal 50c, 50d may be provided between the second housing unit 3 and the valve seat member 12b of the inlet valve 8, or the between the first housing unit 2a and the second housing unit 3a, 3b as described with regard to Fig. 4 Fig. 4, such as has been described above.

The infusion pump is described above with the outlet valve 7 and the inlet valve 8. The outlet valve 7 and the inlet valve 8 may be identical, but oriented differently in the housing 1. The outlet valve 7 is arranged with its spherical valve member 11a towards the outlet 5. The inlet valve 8 may be arranged with its spherical valve member 11 b towards the inlet 6. The outlet 5 and the inlet 6 may be provided in at least one of the first housing unit 2 and the second housing unit 3. In the embodiments of Figs. 1 and 4, the inlet 6 is provided entirely in the second housing unit 3, whereas the outlet 5 is formed partially in the first housing unit 2 and partially in the second housing unit 3.

In some embodiments, the valve seat member 11 a of the outlet valve 7 and the valve seat member 11 b of the inlet valve 8 are provided as a single unit. The first recess 13 and the second recess 15 are provided in a single component, such as a disc shaped element, for each of the outlet valve 7 and the inlet valve 8. This provides for efficient assembly of the infusion pump, wherein the number of components is reduced. A single component may comprise both an inlet valve seat member and an outlet valve seat member. For such an arrangement, a seal may be provided on each side of the single component, which comprises a spring member for biasing the spherical valve member 11a, 11 b on each side. A seal may also be shaped for sealing between the outlet 5 and/or inlet 6 and the single component, which may be formed as an integral unit with the spring member, wherein efficient assembly of the infusion pump is provided for.

Embodiments provide a combined seal and spring member. In some examples, such embodiments are used with an infusion pump according to the invention. The combined seal and spring member may be arranged between the valve seat member 11 and at least one of the first housing unit 2 and the second housing unit 3 of the infusion pump.

Embodiments provide a method for providing an infusion pump according to the embodiments described above. The method comprises providing the first housing unit 2, which comprises at least a portion of the chamber 4 located therein. Also, the second housing unit 3, which may have the outlet 5 and/or the inlet 6, is provided. Furthermore, the outlet valve 7, which may include a first spherical valve member 11 a and a first valve seat member 12a, may be provided. The inlet valve 8, which may include a second spherical valve member 12a and a second valve seat member 11 b may, be provided. The outlet valve 7 may be arranged between the chamber 4 and the outlet 5 in a first space formed by the first housing unit 2 and the second housing unit 3, such as described above. The inlet valve 8 may be arranged between the inlet 6 and the chamber 4 in a second space formed by the first housing unit 2 and the second housing unit 3, such as described above.

In the embodiments described above, the housing 1 is described as comprising a first housing unit 2 and a second housing unit 3 that are provided as separate units that are assembled after the valves 7, 8 are arranged in the first housing unit 2. In other embodiments, the housing is made as a single unit, such as by molding the housing 1 around the other components, for example the outlet valve 7 and inlet valve 8.

In some embodiments, the infusion pump comprises the housing 1 , the chamber 4 located in the housing 1, the outlet 5, the outlet valve 7 between the chamber 4 and the outlet 5, the inlet 6, and the inlet valve 8 between the inlet 6 and the chamber 4. At least one of the outlet valve 7 and the inlet valve 8 may comprise a spherical valve member 11 a, 11 b and a valve seat member 12a, 12b, arranged in the housing. The spring member 30 may be arranged in the housing 1 and to bias the spherical valve member 11 a, 11 b towards the valve seat 14 of the valve seat member 12a, 12b. The spring member 30, 130, 230 may be arranged as has been described above with regard to the embodiments of Figs. 1-6. These embodiments are particularly useful for embodiments of the infusion pump wherein the pressure provided within the chamber 4 is low, and the amount of liquid distributed by moving the piston 16 within the chamber 4 is small. For example, the piston 16 may only move a fraction of the length of the chamber 4 for delivery of a predefined amount of the liquid, such as 0.00010-00050 ml. Thus, the build up of pressure is low when liquid is ejected from the chamber 4. When the chamber 4 is to be re-filled, the piston 16 may traveller with a complete stroke, possibly even faster than when the liquid is ejected. Therefore, depending on the distance and/or speed the piston is travelling for delivery of a predefined amount of liquid, it may be desired to bias the spherical valve member 11 b for the inlet valve 8. However, it may not be required to bias the spherical valve member 11 a for the outlet valve 7. In other embodiments, the piston 16 moves slowly during the inlet phase, wherein it may be desired also to bias the spherical valve member 11 a for the outlet valve 7. In still other embodiment, such as described above with regard to Figs. 1-6, it may be desired that neither the spherical valve member 11a for the outlet valve 7 nor the spherical valve member 11 b for the inlet valve 8 are biased.

The spring member 30, 130, 230 may be configured as has been described above with regard to Figs. 1-6, and be arranged in the housing 1, such as described above with relative to the first housing unit 2 and the second housing unit 3. The spring member 30, 130, 230 may be formed as a single integral component providing a seal, such as described above, and may thus be a component made of an elastic material. Alternatively, the seal and the spring member 30, 130, 230 are provided as separate components.

The spring member 30, 130, 230 may comprise the rim 131, 231 as described above. The rim 131 , 231 may be arranged at a ledge 40, also as described above.

5 In embodiments using the spring member 30, the housing 1 may be made in the same material as the valve seat member 11 , such as described above. In other embodiments, the valve seat member 11 and at least one of the first housing unit 2 and the second housing unit 3 are made of different materials, such as described above. The spring member 30, 130, 230 may be made of a third material, that is more elastic than the material of the housing.

o The spherical valve member may be made of an plastic material, such as a metallic or a ceramic material.

Fig. 7 illustrates the inlet 6 of the infusion pump according to the embodiments described above arranged in fluid communication with a reservoir for a liquid medicament or a nutrient. When not otherwise described, aspects described with reference to the valve 10 and its arrangement within 5 the housing 1 of the infusion pump, such aspects are applicable to any of the outlet valve 7 and the inlet valve 8. The reservoir may have an arbitrary shape and may be collapsible.

Still alternative embodiments provide a method for providing an infusion pump. Such alternative methods includes providing a housing comprising a chamber 4, an outlet 5, and an inlet 6; providing an outlet valve 7 comprising a first spherical valve member 11 a and a first valve seat

0 member 12a, which comprises a first valve seat 14; providing an inlet valve comprising a second spherical valve member 11 b and a second valve seat member 12b, which comprises a second valve seat 14; providing at least one spring member 30, 130, 230; arranging the outlet valve 7 between the chamber 4 and the outlet 5; arranging the inlet valve 8 between the chamber 4 and the inlet 6;

biasing at least one of the first spherical valve member 11 a towards the first valve seat 12a and the 5 second spherical valve member 11 b towards the second valve seat 12b using said at least one

spring member 30, 130, 230.

The method may comprise arranging the spring member 30, 130, 230 as has been described above with regard to Figs. 1-7.

In still other embodiments, the valve 10 may be provided as a pre-assembled component o that may be produced and tested separately before assembly with the other components of the

infusion pump.

Figs. 8a-8b illustrates embodiments of a pre-assembled valve 410 that comprises a spherical valve member 11 , a valve seat member 12, and a spring member 230. The spring member may be seated at a ledge 413 formed at a proximal end of a recess 414 at one end of the valve seat 5 member 12. The spherical valve member 11 is arranged at least partially between the ledge 413 and the valve seat 14. The valve seat 14 may be arranged at a distal end of the recess 414. A small portion of the spherical valve member 11 extends between the end of the valve seat member 12 and the ledge 413 such that it is biased towards the valve seat 14, as has been discussed before. The diameter of the recess 414 at its proximal end may be slightly smaller than the remaining portion of the recess towards the ledge 413, whereby at least one flange 415 is provided at the proximal end of the valve seat member 12. The flange 415 may extend towards the central longitudinal axis of the recess 414 and have a minimum diameter slightly smaller than a maximum diameter of the spring member 230. Hence, the spring member may be secured in the recess 414 between the ledge 413 and the flange 415. The spring member 230 is illustrated as spiral, but may have other shapes as discussed above. In the illustrated embodiments, the valve seat member 12 has two circumferential recesses for receiving seal members 50a, 50b (not illustrated), such as o-rings, to seal against the first and/or the second housing member 2, 3, such as described above. In other embodiments one, more than two, or no such recesses are provided. Providing the valve 410 as a pre-assembled component provides for efficient assembly of the infusion pump. The valve 410 may be a critical component for the functioning of the infusion pump. Hence, when provided as a separate component, it may be quality tested before assembly with the other components. That means that only approved valves are assembled with the other components. Hence, the scrap compared to performing the quality testing after assembly with the housing components may be reduced. Hence, an overall more efficient assembly of the infusion pump is provided for. Furthermore, it may be produced with productions techniques, such as milling, which is more accurate than production techniques used for the housing.

The infusion pump of the embodiments of presented above may be contained in an infusion pump device, such as an insulin pump. The piston 16 may be connected to a motor, such as a step motor or a piezo motor, which is controlled by various electronics and one or several controllers. The motor may move the piston 16 in at least one step for delivery of a pre-defined amount of liquid, such as a fraction of a unit of insulin. The length of movement of the piston is dependent on the size of the chamber 4, which is fixed, and the amount to be delivered, which is variable. The amount to be delivered may be set in a user interface, and controller software may control the length of travel of the piston 16. The controller software may also be configured to control amount of liquid in the chamber 4, in order to re-fill the chamber 4 at defined intervals, such as when a particular amount of liquid has been delivered between two-refills of the chamber 4, or when a minimum amount of liquid in the chamber 4 has been reached.

The chamber 4 may contain an amount of liquid that provides multiple units of the maximum amount to be delivered in each incremental movement of the piston 16 for delivery of a set amount to be delivered. Hence, the piston 16 can be incrementally moved to delivery set amount of liquid before the chamber 4 needs to be refilled. Yet, the inlet valve 8 and the outlet valve 7 are tuned such that the minimum of liquid that can be delivered is delivered in each incremental movement of the piston 16. The disc spring provides for enhanced control of the inlet and/or outlet valve. Since the pressure in the chamber 4 is low due to the minute amount to be delivered in each set amount, there is a delicate balance between the force applied by the disc spring for the inlet valve 8 and the force applied by the disc spring for the outlet valve 7. For example, the force applied on the inlet valve 8 may be higher that applied on the outlet valve 7. This ensures that the inlet valve 8 is tight during delivery of liquid. However, the pressure on the inlet valve 8 should not be too high such that re-filling of the chamber 4 is prevented when the piston is reversed. A disc spring, where the pattern of the slit can be tailored provides enhanced possibilities to apply the appropriate pressure to the inlet valve 8 and the outlet valve 7. The shape of the slit can be different for the disc spring for the inlet valve 8 compared to the outlet valve 7. This may not only control the pressure applied by the disc spring, but also the flow of liquid through the disc spring. For example, if the return speed of the piston 16 is higher than during forward motion of the piston 16, the slits may be different to allow for increased flow rate. At the same time, a separate pressure may result from the different shape of the slits. In other situations, the slit shape is the same, but the thickness of the disc springs can be varied, which provides for a different pressure on the inlet valve compared to the outlet valve. The shape of the slits, i.e. the total area of the slits of one disc spring, and the thickness of the disc spring can also be combined, such that a disc spring with larger total slit area and thickness can provide a higher pressure compared with a disc spring with lower total slit area and thickness. Further combinations are envisaged, which provides for enhanced possibilities to control pressure on both an inlet valve 8 and an outlet valve 7 connected to the same chamber 4.

Examples

The forgoing description has been described with regard to various embodiments. These embodiments can in combination or separately result at least in the following examples, each of which may form a separate embodiment:

Example 1. An infusion pump, comprising

housing including a first housing unit and a second housing unit;

a chamber located at least partially in the first housing unit;

an outlet;

an outlet valve between the chamber and the outlet;

an inlet; and

an inlet valve between the inlet and the chamber; wherein

at least one of the outlet valve and the inlet valve is arranged between the first housing unit and the second housing unit.

Example 2. The infusion pump according to example 1 , wherein at least one of the outlet valve and the inlet valve comprises a spherical valve member and a valve seat member, and the valve seat member and at least one of the first housing unit and the second housing unit are made of different materials.

Example 3. The infusion pump according to claim 2, wherein the valve seat member is made of a metallic material and comprises a valve seat having a radius corresponding to a radius of the spherical valve member, and the first housing unit comprises a recess for receiving at least a portion of the valve seat member, the first housing unit being made of a non-metallic material.

Example 4. The infusion pump according to example 2 or 3, wherein the first housing unit and the second housing unit are made of the same material and together form a space for enclosing at least one of the outlet valve and the inlet valve, and wherein the valve seat member comprises a recess, in which the spherical valve member is at least partially arranged.

Example 5. The infusion pump according to example 4, wherein the first housing unit comprises a recess sized for receiving at least a portion of the second housing unit, and wherein the first housing unit is joined to the second housing unit.

Example 6. The infusion pump according to example 4 or 5, further comprising a spring member arranged to bias the spherical valve member towards a valve seat of the valve seat member.

Example 7. The infusion pump according to example 6, wherein the spring member comprises a disc spring, such as a spiral disc spring.

8. The infusion pump according to example 6 or 7, wherein the spring member comprises a rim arranged at least partially around a circumference of the spherical valve member.

Example 9. The infusion pump according to example 8, wherein the rim is ring shaped and arranged completely around the circumference of spherical valve member, and wherein the rim forms a seal between the valve seat member and at least one of the first housing unit and the second housing unit.

Example 10. The infusion pump according to any of examples 8 to 9, wherein a spring element of the spring member is formed by at least one slit in a center portion of the spring member.

Example 11. The infusion pump according to any of examples 8 to 10, wherein the spherical valve member is arranged at least partially between the valve seat member and the rim, and wherein a pressure component of the spring member connected to the rim via a spring element and arranged in abutment with the spherical valve member is biased towards and moveable relative the valve seat.

Example 12. The infusion pump according to example 10 or 11 , wherein the rim of the spring member is arranged at a ledge of at least one of the first housing unit and the second housing unit, wherein a height of the ledge is lower than a thickness of the rim in an uncompressed state, and wherein the rim is compressed by the valve seat member when the second housing unit is arranged relative the first housing unit in an assembled state. Example 13. A reservoir for a liquid medicament or a nutrient arranged in fluid

communication with the inlet of the infusion pump according to any of the previous examples.

Example 14. A disc spring arranged between a valve seat member of at least one of the outlet valve and the inlet valve and at least one of the first housing unit and the second housing unit of the infusion pump of any of examples 1 to 12.

Example 15. A method for providing an infusion pump, comprising

providing a first housing unit having a chamber located therein;

providing a second housing unit having an inlet and an outlet;

providing an outlet valve;

providing an inlet valve;

arranging the outlet valve between the chamber and the outlet in at least one space formed by the first housing unit and the second housing unit; and

arranging the inlet valve between the inlet and the chamber in said at least one space formed by the first housing unit and the second housing unit.

Example 16. A disc spring for a valve of an infusion pump, comprising

a rim;

a spring element; and

a circumferential seat in the center of the disc spring, wherein

the spring element is arranged around the circumferential seat, and the rim, the spring element, and the circumferential seat are arranged in a single plane.

Example 17. The disc spring according to claim 16, wherein the rim is ring-shaped, and the spring element is helically shaped and extends from the rim to the circumferential seat, and wherein the circumferential seat is substantially circular.

Example 18. The disc spring according to claim 17, wherein the helically shaped spring element has a first end connected to the rim, and a second free end, wherein the last turn of the helically shaped spring element forms the circumferential seat.

Example 19. The disc spring according to any of examples 16 or 17, wherein

the rim and the spring element are made of a material being elastic;

the spring element is formed by at least one slit in the disc spring; and

the rim is arranged at least partially around the at least one slit.

Example 20. The disc spring according to example 19, comprising at least one substantially straight slit.

Example 21. The disc spring of example 20, comprising at least one curved slit.

Example 22. The disc spring of example 20, comprising a semi-circular slit.

Example 23. The disc spring of any of examples 16 to 22, wherein the rim is circular.

Example 24. The disc spring of any of examples 19 to 23, wherein the rim is ring-shaped and encircles the at least one slit. Example 25. The disc spring of any of examples 19 to 24, wherein the rim is compressible to form a seal in said single plane and the circumferential seat is deflectable to at least a second plane to bias the circumferential seat towards the rim.

Example 26. The disc spring of example 25, wherein rim is compressible to an overall ring- shape and the circumferential seat is stretchable to an overall dome-shape.

Example 27. The disc spring of claim example 25 or 26, wherein disc spring comprises at least one slit having a first end generally opposing a second end of the at least one slit.

Example 28. The disc spring of any of claims 25 to 27, wherein the rim is circular and compressible to a ring-shape and the circumferential seat is disc shaped.

Example 29. A valve for an infusion pump, comprising,

a disc spring according to any of the previous claims,

a spherical valve member, and

a valve seat member comprising a recess with a valve seat at a first end of the recess and a ledge at a second end of the recess, wherein

the spherical valve member is arranged in abutment with the valve seat of the valve seat member,

the rim of the disc spring is arranged in abutment with the ledge,

the circumferential seat of the disc spring is arranged in abutment with the spherical valve member, and

the ledge and the valve seat are separated a distance in the longitudinal axis of the recess such that the spherical valve member is biased towards the valve seat by the disc spring.

As will be apparent, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure.

Conditional language used herein, such as, among others, "can," "could," "might," "may," "e.g.," and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.

Any process descriptions, elements, or blocks in the flow diagrams described herein and/or depicted in the attached figures should be understood as potentially representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process. Alternate implementations are included within the scope of the embodiments described herein in which elements or functions may be deleted, executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those skilled in the art.

The present invention has been described above with reference to specific embodiments. However, other embodiments than the above described are equally possible within the scope of the invention. Different method steps than those described above may be provided within the scope of the invention. The different features and steps of the invention may be combined in other combinations than those described. The scope of the invention is only limited by the appended patent claims.

Claims

1. An infusion pump, comprising

a housing;

a chamber located in the housing;

an outlet;

an outlet valve between the chamber and the outlet;

an inlet; and

an inlet valve between the inlet and the chamber; wherein

at least one of the outlet valve and the inlet valve comprises a spherical valve member, a valve seat member, and a spring member arranged to bias the spherical valve member towards a valve seat of the valve seat member.

2. The infusion pump according to claim 1 , wherein the spring member comprises a disc spring.

3. The infusion pump according to claim 1 or 2, wherein the spring member comprises a rim arranged at least partially around a circumference of the spherical valve member.

4. The infusion pump according to claim 3, wherein the rim is arranged completely around the circumference of the spherical valve member, and wherein the rim forms a seal between the valve seat member and the housing. 5. The infusion pump according to any of claims 2 to 4, wherein a spring element of the spring member is formed by at least one slit in the center of the spring member, whereby the spring element and the rim are formed as a single component, and wherein the rim is ring-shaped. 6. The infusion pump according to any of claims 3 to 5, wherein the spherical valve member is arranged at least partially between the valve seat member and the rim, and wherein a pressure component of the spring member connected to the rim via a spring element and arranged in abutment with the spherical valve member is biased towards and moveable relative the valve seat.

7. The infusion pump according to claims 5 or 6, wherein the rim is arranged at a ledge within a recess of the housing, wherein a height of the ledge is lower than a thickness of the rim in an uncompressed state, and wherein the rim is compressed by the valve seat member when the valve seat member is assembled with the housing.

8. The infusion pump according to any of claims 2 to 7, wherein

the housing includes a first housing unit and a second housing unit;

the chamber is located in the first housing unit;

the spherical valve member and the valve seat member are arranged between the first housing unit and the second housing unit; and

the first housing unit and the second housing unit are joined to form the housing.

9. The infusion pump according to claim 8, wherein the valve seat member and at least one of the first housing unit and the second housing unit are made of different materials.

10. The infusion pump according to claim 9, wherein the valve seat member is made of a metallic material and comprises the valve seat, which has a radius corresponding to a radius of the spherical valve member, and the first housing unit comprises a recess for receiving the valve seat member, the first housing unit being made of a non-metallic material.

12. The infusion pump according to claim 9 or 10, wherein the first housing unit and the second housing unit are made of the same material and together form at least one space for enclosing at least one of the outlet valve and the inlet valve, and wherein the valve seat member comprises a recess, in which the spherical valve member is at least partially arranged.

13. A reservoir for a liquid medicament or a nutrient arranged in fluid

communication with the inlet of the infusion pump according to any of the previous claims.

14. A pre-assembled valve forming at least one of the inlet valve and the outlet valve of the infusion pump of any of claims 1 to 12, comprising

a valve seat member,

a disc-shaped spring member, and

a spherical valve member at least partially arranged between the valve seat member and the disc-shaped spring member.

15. A method for providing an infusion pump, comprising

providing a housing comprising a chamber, an outlet, and an inlet; providing at least one of an outlet valve comprising a first spherical valve member and a first valve seat member, which comprises a first valve seat, and an inlet valve comprising a second spherical valve member and a second valve seat member, which comprises a second valve seat;

providing at least one spring member;

arranging at least one of the outlet valve between the chamber and the outlet, and the inlet valve between the chamber and the inlet;

biasing at least one of the first spherical valve member towards the first valve seat, and the second spherical valve member towards the second valve seat, using said at least one spring member.