Medical pump unit

Abstract

To provide a pump unit capable of being easily ventilated.SOLUTION: The pump unit 10 has at least one cylinder 11 in which a piston 21 is displaceably supported, has a first channel 25 connected to the cylinder 11, in which a first valve 27 having a first valve closure member 32 ' assigned to a first valve seat 38 ' is arranged, and has a second channel 26 connected to the cylinder 11, in which a second valve 28 having a second valve closure member 32 assigned to a second valve seat 38 is arranged. The first valve 27 functions as an inlet valve and the second valve 28 functions as an outlet valve, wherein the first valve 27 and the second valve 28 are arranged one above the other and the second valve 28 is arranged above the first valve 27.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The invention relates in particular to pump units for medical applications, for example for water jet surgery. [Background technology]

[0002] For the purposes indicated, piston pumps for medical or other applications are known from German Patent Application Publication No. DE 102004031673, European Patent Application No. 2730240, German Patent Application Publication No. DE 2048832, U.S. Patent Application Publication No. 2014 / 01217037, European Patent Application No. 1735030, European Patent Application No. 2222957, U.S. Patent Application No. 8491526, European Patent Application Publication No. 2758097, and German Patent Application Publication No. DE 69429306. Such piston pumps are often provided with two pistons that are driven in opposite directions and alternately draw in and deliver a fluid, such as a liquid medical treatment fluid, e.g., a sodium chloride solution. For this purpose, each cylinder is typically provided with an inlet valve and an outlet valve, which can be configured to be identical or different. WO 2013 / 043881 discloses a pump unit for a total of four cylinder inlet and outlet valves, the closing members of which are formed by small flexible dome-shaped discs held in valve chambers, and which open and close the respective inlet or outlet openings in response to varying fluid pressure.

[0003] EP 2 711 545 A1 discloses a pump unit having two cylinders, the inlet and outlet valves of which are ball valves. In particular, ball valves are used, the balls of which are loosely held in the valve chamber, i.e., they are freely movable. The valve balls can be made of metal or plastic. The free movement of the valve balls in the valve chamber allows for particularly easy sterilization of the pump with sterilizing gas.

[0004] Valves with non-spherical and non-disk-shaped closing valve members for hydraulic vehicle shut-off systems are also generally known, for example from DE 10 2007 052 ​​755 A1. Additionally, EP 1 980 291 A1 shows a medical valve with a substantially mushroom-shaped elastic closing valve member made of rubber material. The closing valve member is positioned on the valve seat with its edge facing the shank, thus forming a sealing pair on the outside.

[0005] EP 2924285 A1 also discloses a valve having a mushroom-shaped closing valve member, the edge of which is provided with a flow opening. The valve's shank protrudes into the downstream flow channel, and its convexly curved surface facing outward from the shank rests on a valve seat. The resilience of the closing valve member's substantially plate-shaped head generates a spring force that causes the head's convex sealing surface to abut against a valve seat in the form of a ring rib surrounding the inlet flow channel. Such valves are generally well suited for medical applications, but can reach their limits at high flow rates. This is especially true when the fluid flow is so great that the closing valve member is displaced within the downstream channel and subsequently blocks it.

[0006] Another problem that can arise with the pumps mentioned above is if gas or bubbles remain in the pump apart from the liquid being delivered. The pump must be as easily vented as possible. Additionally, a simple and easy to maintain sterility design is desirable. Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to solve at least one of the above problems. [Means for solving the problem]

[0008] This object is solved by a pump unit according to claim 1.

[0009] The pump unit according to the invention comprises at least one, preferably two, cylinders in each of which a piston is movably supported. The pistons are sealed against the cylinder wall and for this purpose are provided with heads, for example made of an elastic material. At the end opposite the head, a piston rod connected to the piston protrudes from the cylinder and is provided at its free end with a coupling device by means of which it can be coupled, preferably in a form-fitting manner, to a drive.

[0010] The cylinder is connected to a first channel serving as an inlet channel, in which a first valve serving as an inlet valve is disposed. The cylinder is also connected to a second channel serving as an outlet channel, in which a second valve serving as an outlet valve is disposed. At least one of the two valves is mushroom- or umbrella-shaped, i.e., has a substantially disk-shaped head and a shank extending away from the center of the disk. The closing valve member is supported with or without play within the valve. The closing valve member can be arranged so that one side of the closing valve member is supported on the valve seat facing outward from the shank, and the other side is supported without play on an abutment portion at the free end of the shank opposite the valve seat. This allows the closing valve member to be made of a single elastic material, such as a rubber-like material. The closing valve member can open the valve seat and thus the flow passage, by slightly bending the valve head away from the valve seat and / or slightly compressing the shank of the closing valve member. In this case, the sealing surface of the closing valve member facing the valve seat can move slightly away from the valve seat as a whole. In this way, the flow resistance of the valve is reduced in the open position. This concept, in which the shank of the closure member serves to support and center the closure member, further prevents the closure member from being carried away and pushed into the downstream channel in the event of high flow velocities.

[0011] Preferably, the abutment on which the shank section is supported on its face side is part of a support device that does not allow fluid to flow through and surrounds the shank section. The face end of this support device can simultaneously serve as a support surface for the head section of the valve-closing member, ensuring that the head section is securely held in a defined axial position in the open position. The support device preferably comprises a pocket closed on five sides (bottom and periphery) in which the shank section is located. The support device, together with the channel in which it is located, can define a ring-shaped flow cross section. This concept allows for flow guidance with slight deflections and securely surrounds or supports the valve-closing member. This also applies when the valve-closing member is held with play in the valve. Such an embodiment ensures that the valve-closing member cannot be undesirably displaced and, in the worst case scenario, cannot flow out into the channel after its shank is captured by the support device.

[0012] Regardless of the specific valve configuration, it is advantageous to arrange two or more cylinders of a pump unit horizontally and vertically one above the other during use. This simplifies venting the pump unit. This is the case when, in each cylinder, the second valve acting as the outlet valve is located above the first valve acting as the inlet valve. This ensures that the outlet channel exits the cylinder as close as possible to the cylinder wall. This ensures that air bubbles are pushed out of the cylinder so that the generated liquid flow accurately follows the setting of the pump.

[0013] In addition, it is advantageous in the pump unit described in claim 1 and in pump units in general if the cylinder has first and second sections with different diameters. The first section, located closer to the valve, preferably has a smaller diameter. The second section, located further from the valve, preferably has a larger diameter. The axial length of the second section is preferably at least as long as the axial length of the first section. Preferably, two seals are arranged on the piston, with the first seal assigned to the first section and the second seal assigned to the second section. Thus, the distance between the first and second seals is preferably equal to or greater than the length of the first section. The first seal serves to seal the sterile pump volume defined by the piston within the cylinder. The second seal serves to seal the pump unit from the outside and prevent non-sterile contaminants from entering the pump unit. The two seals seal against the cylinder wall, i.e., the inner surface of the cylinder. A bellows seal or the like, which serves to seal the piston rod against the cylinder, can be omitted.

[0014] Further embodiments result from the drawings, the description or the claims. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a partially cutaway perspective view of the pump unit; [Figure 2] FIG. 2 is a longitudinal section through a cylinder of the pump unit according to FIG. 1 with inlet and outlet channels. [Figure 3] 3 is an enlarged longitudinal section of the pump unit according to FIGS. 1 and 2 in the closed position of the valve; FIG. [Figure 4] 4 is a view of the valve according to FIG. 3 in the open position. [Figure 5] 2 is a schematic front view of the pump unit according to FIG. 1, highlighting the channel extension. [Figure 6] FIG. 6 is a longitudinal sectional view of a cylinder of the pump unit shown in FIGS. 1 to 5. [Figure 7] FIG. 3 is a view of a pump unit similar to FIG. 2 with a modified channel configuration. [Figure 8] FIG. 5 is a view of a valve similar to FIGS. 3 and 4 in a modified configuration. DETAILED DESCRIPTION OF THE INVENTION

[0016] 1 shows a pump unit 10 that can be used to transport fluids, in particular liquids, for example, sterile medical products, in respective containers of a device. For this purpose, the pump unit 10 comprises two cylinders 11, 12 and a cylinder head 13, from which the cylinders 11, 12 extend. A connecting element 14 is arranged on the cylinder head 13, through which fluid can be supplied to the two cylinders 11, 12. A hose leading to a liquid container, for example, a pouch, can be connected to the connecting element, for example, an attachment 15. Additionally, an outlet connector 16 is provided on the cylinder head 13, to which an instrument that needs to receive fluid from the pump unit 10 can be connected.

[0017] From the cylinders 11, 12 project piston rods 17, 18, each provided at its free end with a coupling means 19, 20. The coupling means 19, 20 allow connection of the piston rods 17, 18 with a suitable drive device for moving the piston rods 17, 18, preferably opposite to each other, in particular axially, within the cylinders 11, 12.

[0018] The above-mentioned connecting member 14 is made, for example, from a flexible material and is detachable from the cylinder head 13. In this way, both cylinders 11, 12 can be equally supplied with fluid introduced via the attachment 15. However, it is also possible to connect the two cylinders 11, 12 to different fluid sources in order to output a liquid mixture or temporarily different liquids at the connector 16, for example a flushing liquid and a treatment liquid.

[0019] The two cylinders 11, 12 are preferably configured identically, so the following description of cylinder 11 also applies to cylinder 12 accordingly.

[0020] As shown in Figure 2, a piston 21 is supported within the cylinder 11 with a head 23 sealed against a wall 22 of the cylinder 11. The head 23, together with the wall 22, defines a working volume 24 within the cylinder 11, which is connected to a first channel 25, which functions as an inlet channel, and a second channel 26, which functions as an outlet channel. A first valve 27, which functions as an intake valve, is disposed within the first channel 25. A second valve 28, which functions as an outlet valve, is disposed within the second channel 26.

[0021] A particular feature of the pump unit 10 of the present invention is the configuration of at least one of the valves 27, 28. The two valves 27, 28 can be configured identically. They are self-regulating (differential pressure controlled) valves, so-called check valves.

[0022] The following description of valve 28 therefore also applies to valve 27.

[0023] 3, where the valve 28 is shown in the rest or closed position, and the flow direction arrows 29, 30, 31 are therefore shown as crosses since no fluid flow occurs.

[0024] The valve 28, as is evident from the longitudinal section in Figure 3, comprises a closure member 32 which is substantially mushroom-shaped and preferably made in one single piece of elastic material. A preferably straight shank 34 extends away from a generally disk-shaped, preferably slightly domed, head 33. At its distal end 35, the shank 34 abuts against an abutment 36 which is fixedly arranged in the channel 26.

[0025] The head 33 preferably has a sealing surface 42, preferably slightly domed, facing outward from the shank 34 and abutting against the valve seat 38. The valve seat 38 is preferably configured as a ring-shaped circular protrusion that surrounds the inlet portion 39 of the channel 26. Outside the valve seat 38, the head 33 may have a cavity.

[0026] Valve 28 operates as follows.

[0027] As shown in Figure 3, the closing valve member 32 is held between the valve seat 38 on one side and the abutment 36 on the other side, with or without play. In the embodiment according to Figures 3 and 4, the closing valve member 32 is held between the abutment 36 and the valve seat 38 without play. The channel 26 is thus blocked. Fluid cannot flow in the flow direction indicated by the arrows 29, 30, 31. To clarify this situation, the arrows 29-31 are shown as crosses.

[0028] Next, when a sufficient pressure difference occurs such that the piston reduces the working volume 24, the fluid present in the working volume 24 urges the head 33 away from the valve seat 38, and the head 33 can deform slightly, in that its edges are curved up towards the ring-shaped region of the channel 26. This ensures that the shank 34 is held securely within a support structure 40 that is immovably arranged within the channel 26. The abutment portion 36 can thereby form the bottom of a pocket-like or blind-hole-like cavity in which the shank 34 is arranged, and can, for example, form another end, such as the end of the pin-like support structure 40 that faces the head 33. The face end of the support structure 40 that faces the head 33 is preferably formed by a surface 41 against which the head 33 can abut when the shank 34 is compressed.

[0029] As shown in FIG. 4, the dome-shaped sealing surface 42 of the head 33 facing the valve seat 38 26, and thus opens a flow path for the fluid, in particular the liquid. This allows the shank 34 to be slightly compressed and the head 33 to be slightly deformed. Arrows 29, 30 indicate the direction of flow passing through the ring-shaped flow cross-section of the channel 26 and thus around the outer support structure. The flow indicated by arrows 29, 30 flows from the head 33 to the ring cross-section of the channel 26 and thereby does not flow radially inward towards the shank 34 in any case.

[0030] Because the shank 34 is securely held in the support structure 40 and fluid cannot flow along the shank 34, the closing member 32 cannot be carried out of its container by the flow into the channel 26, and therefore the closing member remains operable even at high flow rates. On the other hand, the closing member already responds to small pressure differentials, thus allowing adjustment of low effect sizes that require operation at very low flow rates. In addition, the valve described so far is also suitable as an inlet valve (valve 27 in Figure 2). The low pressure differential required to open the valve makes it very suitable as an intake valve, allowing liquid to be sucked in even if the cylinder 11 or 12 is initially filled only with air.

[0031] Regardless of the specific configuration of valves 27 or 28, valves 27, 28 are preferably arranged one above the other, as shown in FIG. 5. Thus, upper valve 28 functions as an outlet valve, while lower valve 27 preferably functions as an inlet valve. Lower cylinder 12 thus has first valve 27' as an inlet valve and second valve 28' as an outlet valve. Channel 26 thereby connects both outlet valves 28, 28', which are connected to the respective cylinders 11, 12 at their tops. As specifically shown in FIG. 7, channel 26 preferably exits the respective cylinder 11 or 12 immediately adjacent wall 22. However, the location of first valve 27 is dependent.

[0032] This concept makes the pump unit 10 particularly easy to vent: air contained in the cylinders 11, 12 is easily removed and forced out through the channel 26 by the pumping movement of the respective pistons.

[0033] Although the two valves 28, 28' open into the same channel 26 rigidly formed in the cylinder head 13, the first channel 25 serving as the liquid inlet can be accessed separately via a connecting structure 43, for example in the form of a fluid socket. This applies regardless of the other configurations of the pump unit 10. The connecting structure 43 can be, for example, an opening into which a fluid plug can be inserted. Similarly, the first channel 25' leading to the first valve 27' of the second cylinder 12 can open in a connecting structure 43', for example in the form of a fluid socket. Thus, separate liquid containers can be connected to the two cylinders 11, 12 or the channels 25, 25', respectively, in order to fill the two cylinders 11, 12 with different liquids and thus supply different liquids to one and the same appliance. However, as shown together in Figures 1 and 5, it is also possible to construct a connecting element 44, for example made of flexible plastic, which has an internally branched channel opening onto two plugs 44, 44' that can be inserted into the connecting structure 43, 43'.

[0034] 8 shows a modification of the valve 28 (or 27) independent of the other components of the pump unit 10. It can be configured as described above or can deviate from it. Unlike the valve 28 described above, the valve 28 shown in FIG. 8 comprises a support structure 40 in which the distance between the abutment 36 and the valve seat 38 is longer than the length of the closing valve member 32 measured in the same direction. This makes the position of the closing valve member 32 indeterminate in the pressure-free state. However, a slight movement of the liquid is sufficient to urge the head 33 of the closing valve member 32 towards or away from the valve seat 38. This allows the large umbrella-shaped head 33 to act as a barrier against the flow. This provides a positive transition of the closure member 32 to either the closed or open position depending on the direction.

[0035] Also, in this embodiment of the valve 28, the shank 34 of the closing member 32 is securely held within the support structure 40, and the face of the support structure 40 facing the head 33 again forms a support surface 41 against which the head 33 can be supported when the valve 28 is moved to the open position. The valve 28 shown in FIG. 8 functions as an outlet valve. In this configuration, it can also be used as an inlet valve. According to the examples of FIGS. 3 or 4, both valves 27, 28 can be identically configured. Both valves 27, 28 can be identically configured according to the example of FIG. 8, if desired. Furthermore, it is possible to configure a valve according to the example of FIG. 8, e.g., a first valve 27, and a second valve 28 according to the examples of FIGS. 3 and 4, or vice versa.

[0036] FIG. 6 shows the configuration of the pistons 21 and their assigned cylinders 11. This configuration can be selected independently of the characteristics of the valves 27, 28 or other details of the pump unit 10 in a pump unit with one or more cylinders. The cylinder 11 comprises a first section 45 having a length L1 (pump section) with a diameter D1. A second section 46 (seal section) having a length L2 and a diameter D2 adjoins the first section 45. Thus, the diameter D2 is preferably at least slightly larger than the diameter D1. Between the two sections 45 and 46, a short conical tapered section can be provided, where the wall 22 transitions from the diameter D2 to the diameter D1. Thus, the length of the second section L2 is preferably at least as large as the length L1.

[0037] The piston 21 includes a sealing body 47, which seals against the wall 22 and, for this purpose, includes a circular lip directed radially outward. The piston 21 includes a non-circular, e.g., cruciform, section in the area facing outward from the sealing body 47. At a distance L3 measured from the face of the sealing body 47, the piston 21 includes a disk-shaped section 48 adjacent to the piston rod 17. The disk section 48 includes a seal 49, e.g., an O-ring seal, a lip seal, or the like, that seals with the cylinder wall 22. During the piston 21's proper forward and backward movement, i.e., during a complete pump stroke, the sealing body 47 passes through the first section 45. In other words, the pump stroke of the piston 21 is less than the length L1. Therefore, the disk section 48, including the seal 49, moves only within the second section 46. The piston 21 with the sealing body 47 confines the sterile working volume 24, and the seal 49 in the disc section 48 ensures that environmental microorganisms are kept out of the area enclosed between the sealing body 47 and the seal 49 so as to ensure the sterility of the wall 22 of the first section 45.

[0038] The pump unit 10 of the present invention includes at least one improved valve 28 (or 27), in which a non-ball-shaped closing member 32 is securely held within a support structure 40, which is surrounded by the external flow. The shank 34 of the closing member 32 is held within a pocket-like container in the support structure 40, ensuring that the closing member 32 is securely held in place even at high flow rates. For this purpose, the support structure 40 is surrounded only by the external flow. The shank 34 is located within a container formed within the support structure 40, for example, in the form of a blind hole, through which no flow passes. Preferably, the pump unit is provided with two cylinders 11, 12, which are arranged horizontally but vertically above each other. However, it is particularly preferred that the first valve 27 and the second valve 28 are arranged one above the other. Preferably, the second valve 28, assigned to the outlet channel, is then arranged directly adjacent to the cylinder wall 22 at its vertical highest point. This simplifies venting of the pump unit 10. [Explanation of symbols]

[0039] 10 Pump unit 11 Upper cylinder 12 Lower cylinder 13 Cylinder head 14 Connecting member 15 Attachments 16 connectors 17 Upper piston rod 18 Lower piston rod 19 Upper coupling means 20 Lower coupling means 21 Piston 22 Wall of cylinder 11 23 Head of piston 21 24 Working volume 25, 25' First Channel / Inlet Channel 26 Second Channel / Exit Channel 27, 27' First valve / inlet valve 28, 28' Second valve / outlet valve 29-31 Arrows to indicate flow direction 32 Closing valve member 33 Head of closing valve member 32 34 shank of valve closing member 32 35 End of closing valve member 32 36 Contact part 38, 38' Valve seat (ribbed ring-shaped protrusion) 39 Part of Channel 26 40 Support structure 41 Support surface 42 sealing surface 43, 43' connecting structure 44, 44' plug 45 Cylinder 11, first section L1: length of the first section 45 of the cylinder 11 D1 Diameter of first section 45 46 Second section of cylinder 11 L2: Length of the second section 46 of the cylinder 11 D2 Diameter of second section 46 47 Seal body 48 Disc Section 49 Seals

Claims

1. A pump unit (10) in particular for medical applications, in particular for water jet surgery, comprising: The piston (21) has at least one cylinder (11) displaceably supported therein; a first channel (25) connected to the cylinder (11) and having a first valve (27) disposed therein, the first valve (27) having a first closing valve member (32') assigned to a first valve seat (38'); A pump unit having a second channel (26) connected to a cylinder (11) and having a second valve (28) arranged therein, the second valve (28) having a second closing member (32) assigned to a second valve seat (38), A pump unit characterized in that the first valve (27) functions as an inlet valve, the second valve (28) functions as an outlet valve, the first valve (27) and the second valve (28) are arranged one above the other, and the second valve (28) is arranged above the first valve (27).

2. 2. A pump unit according to claim 1, characterized in that the first valve (27) and the second valve (28) are differential pressure controlled valves.

3. 3. A pump unit according to claim 1 or 2, characterized in that the piston (21) is sealed against a cylinder wall (22) and the second valve (28) is arranged directly adjacent to the cylinder wall (22) at its vertical highest point.

4. 2. A pump unit according to claim 1, characterized in that at least one of said closing valve members (32) is made of elastic material and is integrally formed without joints.

5. 5. A pump unit according to claim 1 or 4, characterized in that at least one of the closing valve members (32) comprises a dome-shaped sealing surface (42) facing the valve seat (38).

6. 2. A pump unit according to claim 1, characterized in that at least one of the valve seats (38) is a ring-shaped rib-like projection surrounding the inlet opening.

7. 2. The pump unit of claim 1, wherein at least one of the closing valve members (32, 32') is held in a flow-tight support structure (40) and comprises a resilient shank section (34) opposite a valve seat (38, 38'), and wherein at least one of the closing valve members (32) comprises a head section (33), the resilient shank section (34) extending outwardly from the head section (33).

8. 8. A pump unit according to claim 7, characterized in that the shank section (34) is configured straight and pressure-elastic.

9. 9. The pump unit according to claim 7, wherein at least one of the closing valve members is held without play between an abutment portion formed on a support structure of the closing valve member and the valve seat.

10. 10. A pump unit according to claim 9, characterized in that the support structure (40) is arranged to surround the shank section (34).

11. 11. A pump unit according to claim 10, characterized in that the support structure (40) is arranged in the channel (26) and defines, together with the walls of the support structure (40), a ring-shaped flow cross section.

12. 2. A pump unit according to claim 1, characterized in that it comprises two cylinders (11, 12) each arranged horizontally.

13. 13. Pump unit according to claim 12, characterized in that the two cylinders (11, 12) are arranged vertically above one another.

14. 14. A pump unit according to claim 1, 12 or 13, characterized in that the cylinder (11, 12) comprises a first section (45) and a second section (46), the second section (46) having a diameter (D2) greater than the diameter (D1) of the first section (45).

15. 15. The pump unit according to claim 14, characterized in that the piston (21) is provided with seals (47, 49) in the first section (45) of the cylinder (11, 12) and in the second section (46) of the cylinder (11, 12), respectively, for sealing the piston (21) to the cylinder (11, 12).

16. 16. Pump unit according to claim 15, characterized in that the first section (45) and the second section (46) of the cylinder (11, 12) are each at least as long as the maximum pump stroke of the piston (21).

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