Pump unit for medical purposes

Abstract

The pump unit (10) for medical purposes according to the invention comprises at least one improved valve (28) (or 27), in which a non-spherical valve closing member (32) is reliably retained in a support structure (40), and in which the support structure (40) is surrounded by an external flow. The shank (34) of the valve closing member (32) is retained in a bag-shaped receptacle of the support structure (40) such that the valve closing member (32) is reliably retained in position even with high flow rates. For this purpose, the support structure (40) is exclusively surrounded by an external flow. The shank (34) is located in a receptacle formed in the support structure (40), for example in the form of a blind hole, and there is no flow therethrough. Preferably, the pump unit is provided with two cylinders (11, 12) which are arranged in a lying manner so as, however, to be arranged vertically one above the other. However, in particular, the first valve (27) and the second valve (28) are preferably arranged one above the other. In this way, preferably, a second valve (28) assigned to the outlet channel is arranged adjacent to the cylinder wall (22) at the vertically highest point of the cylinder wall (22). This simplifies ventilation of the pump unit (10).

Description

Technical Field

[0001] This application is a divisional application. The application date of the original application is November 26, 2021, the application number is 202111422185.1, and the invention name is “Pump unit for medical purposes”. The present invention relates to a pump unit, which is particularly used for medical purposes, such as for water jet surgery. Background Art

[0002] For the specified purpose of medical or other purposes, piston pumps are known from DE 102004031673 A1, EP 2730240B1, DE 2048832A1, US2014 / 01217037A1, EP 1735030B1, EP 2222957 B1, US 8491526 B2, EP2758097 A1 and from DE 69429306T2. Such piston pumps are usually provided with two pistons, which are driven in opposite directions and alternately suck and convey fluids, such as liquid medical treatment fluids, such as sodium chloride solutions. For this reason, each cylinder is typically provided with an inlet valve and an outlet valve, which can be constructed the same or differently. For this reason, WO 2013 / 043881 A1 discloses a pump unit for four cylinder inlet valves and outlet valves in total, and its valve closing member is formed by a dome flexible small disc held in a valve chamber. Due to the changing fluid pressure, the pump unit opens or closes the corresponding inlet opening or outlet opening.

[0003] From EP 2711545 A1 a pump unit with two cylinders is known, the inlet valve and the outlet valve of which are respectively ball valves. In particular, ball valves are used, the balls of which are loosely held in the valve chamber, i.e. they are held freely movable. The valve balls can be made of metal or plastic. The free mobility of the valve balls in the valve chamber allows particularly easy sterilization of the pump by means of sterilizing gas.

[0004] In general, valves with non-spherical and non-disc-shaped valve closing members are also known, such as for example from DE 10 2007 052 ​​755 A1, which is used in hydraulic vehicle brake systems. Furthermore, EP 1 980 291 A1 shows a valve for medical use, which has a substantially mushroom-shaped elastic valve closing member of rubber material. The valve closing member is positioned with its edge facing in the direction of the stem on the valve seat and in this way forms a sealing pair on the outside.

[0005] In addition, EP 2924285 A1 discloses a valve having a mushroom-shaped valve closing member, the edge of which includes a flow opening. Its handle protrudes into the downstream side flow channel, while its convex curved surface facing away from the handle is located on the valve seat. The elasticity of the substantially plate-shaped head of the valve closing member generates a spring force, with which the convex sealing surface of the head abuts against the valve seat in the form of an annular rib surrounding the inlet flow channel. Such valves are generally very suitable for medical use, however, in the case of high flow rates, they may reach their limits. This is particularly applicable to situations where the fluid flow is so large that the valve closing member is displaced in the downstream side channel and then blocks the channel.

[0006] If, in addition to the liquid to be delivered, bubbles or air bubbles remain in the pump, this may lead to another problem that occurs with the above-mentioned pumps. The pump should be as easy to ventilate as possible. In addition, it is desirable that the construction be simple and able to be easily kept sterile. Summary of the invention

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

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

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

[0010] The cylinder is connected to a first channel used as an inlet channel, in which a first valve used as an inlet valve is arranged. In addition, the cylinder is connected to a second channel used as an outlet channel, in which a second valve used as an outlet valve is arranged. At least one of the two valves is mushroom-shaped or umbrella-shaped, that is, it includes a substantially disc-shaped head section and a handle extending away from the center of the disc. The valve closing member is supported in the valve with or without play. It can be arranged in a free-swimming manner, supported on the valve seat with a face away from the handle on one side, and supported on the abutment opposite to the valve seat with the free end of the handle on the other side. Therefore, the valve closing member can be made of an elastic material as a single piece, such as a rubber-like material. The valve closing member can open the valve seat, and therefore open the fluid channel, because the valve head is slightly bent away from the valve seat, and / or because the handle of the valve closing member is slightly compressed. In doing so, the sealing surface of the valve closing member facing the valve seat can be moved slightly away from the valve seat as a whole. In this way, the flow resistance of the valve in the open position is reduced. According to this concept in which the stem of the valve closing member is used to support and center the valve closing member, it is also excluded that the valve closing member is entrained and pressed into the downstream side channel in the case of high flow speeds.

[0011] Preferably, the abutment on which the handle segment is supported on its face side is part of a support arrangement, through which the fluid does not flow and which surrounds the handle segment. The face end of the support arrangement can simultaneously be a support surface of the head segment of the valve closing member, so that it is in a defined axial position in the open position and remains reliably held. The support arrangement preferably includes a bag closed on five sides (on the bottom and the periphery), in which the handle segment is located. The support arrangement can define an annular flow cross section together with the channel in which the support arrangement is arranged. This concept allows reliable encirclement or support of the valve closing member with a flow guide with a slight deflection. This also applies to the case where the valve closing member is held in the valve with clearance. In such an embodiment, it is also ensured that the valve closing member will not be misplaced unexpectedly, and in the worst case, even after its handle is captured in the support arrangement, it is flushed in the channel.

[0012] Independent of the specific configuration of the valves, it is advantageous to arrange two or more cylinders of the pump unit horizontally and vertically one above the other in use. This simplifies the ventilation of the pump unit. This is applicable if a second valve serving as an outlet valve in each cylinder is arranged above a first valve serving as an inlet valve. Thus, the outlet channel leaves the cylinder as close as possible to the cylinder wall. In doing so, air bubbles can be reliably driven out of the cylinder so that the resulting liquid flow precisely follows the settings of the pump.

[0013] In addition, it is advantageous in the pump unit according to claim 1 and in pump units in general if the cylinder comprises a first section and a second section with different diameters. Therefore, the first section close to the valve preferably comprises a smaller diameter. The second section located away from the valve preferably comprises 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, wherein the first seal is assigned to the first section and the second seal is assigned to the second section. Therefore, the distance between the first and second seals is preferably as long as or longer than the length of the first section. Therefore, the first seal is used to seal the sterile pump volume limited by the piston in the cylinder. The second seal is used to seal the pump unit outwardly and prevent non-sterile contaminants from entering the pump unit. The two seals are sealed at the wall of the cylinder, i.e. at its cylindrical inner surface. A bellows seal or the like, which was originally used for the sealing of the piston rod against the cylinder, can be omitted. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Further embodiments are apparent from the drawings, the description or the claims. In the drawings:

[0015] Figure 1 The pump unit is shown in a perspective view, partly in section,

[0016] Figure 2 The longitudinal cross-section diagram shows the Figure 1 a cylinder of a pump unit having inlet and outlet passages,

[0017] Figure 3 The enlarged longitudinal section shows the closed position according to Figure 1 and Figure 2 The valve of the pump unit,

[0018] Figure 4 Shown in open position according to Figure 3 The valve,

[0019] Figure 5 A schematic front view is shown according to Figure 1 The pump unit, with its channel extension emphasized,

[0020] Figure 6 The longitudinal cross-section diagram shows the Figures 1 to 5 The cylinder of the pump unit,

[0021] Figure 7 shows a similar structure to that of Figure 2 The pump unit, and

[0022] Figure 8 shows a modified configuration similar to Figure 3 and Figure 4 valve.

[0023] List of reference numerals:

[0024] 10 Pump unit

[0025] 11 Upper cylinder

[0026] 12 Lower cylinder

[0027] 13 Cylinder head

[0028] 14 Connectors

[0029] 15 Attachments

[0030] 16 Connectors

[0031] 17 Upper piston rod

[0032] 18 Lower piston rod

[0033] 19 Upper connecting part

[0034] 20 Lower connecting part

[0035] 21 Piston

[0036] 22 Wall of cylinder 11

[0037] 23 Head of piston 21

[0038] 24 Working volume

[0039] 25,25' First channel / entrance channel

[0040] 26 Second channel / exit channel

[0041] 27,27' First valve / inlet valve

[0042] 28,28' Second valve / outlet valve

[0043] 29–31 Arrows used to show flow direction

[0044] 32 Valve closing member

[0045] 33 Head of valve closing member 32

[0046] 34 handle of valve closing member 32

[0047] 35 End of valve closing member 32

[0048] 36 abutment

[0049] 38,38' valve seat (ribbed annular protrusion)

[0050] 39 Section of channel 26

[0051] 40 Support structure

[0052] 41 Support surface

[0053] 42 Sealing surface

[0054] 43,43' connection structure

[0055] 44,44'

[0056] 45 First section of cylinder 11

[0057] L1 Length of the first section 45 of the cylinder 11

[0058] D1 Diameter of the first section 45

[0059] 46 The second section of the cylinder 11

[0060] L2 Length of the second section 46 of the cylinder 11

[0061] D2 Diameter of the second section 46

[0062] 47 Sealing body

[0063] 48 disc segments

[0064] 49 Seals. DETAILED DESCRIPTION

[0065] exist Figure 1 In the figure, a pump unit 10 is shown, which can be used as a sterilized medical product, for example, in a corresponding receptacle of the device, in order to convey a fluid, in particular a liquid. To this end, the pump unit 10 comprises two cylinders 11, 12 and a cylinder head 13, the cylinders 11, 12 extending away from the cylinder head 13. A connector 14 is arranged on the cylinder head 13, via which a fluid can be supplied to the two cylinders 11, 12, and a hose can be connected to the connector 14, for example to an accessory 15, which leads to a liquid container (for example a bag). In addition, an outlet-side connector 16 is arranged on the cylinder head 13, to which an instrument can be connected, which instrument must be supplied with fluid from the pump unit 10.

[0066] The piston rods 17, 18 extend from the cylinders 11, 12, which are provided at their free ends with coupling parts 19, 20, respectively. The coupling parts 19, 20 allow the piston rods 17, 18 to be connected to suitable drive means, in order to move the piston rods 17, 18 axially preferably relative to each other, in particular in the cylinders 11, 12.

[0067] The above-mentioned connection piece 14 is made of a flexible material, for example, and can be removed from the cylinder head 13. In this way, the two cylinders 11, 12 can be equally supplied with a 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, such as a flushing liquid and a treatment liquid.

[0068] The two cylinders 11 , 12 are preferably constructed identically. Therefore, the subsequent description of the cylinder 11 also applies to the cylinder 12 accordingly.

[0069] like Figure 2 As shown, a piston 21 is supported in the cylinder 11, the piston comprising 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 inside the cylinder 11, which is connected to a first channel 25 serving as an inlet channel and a second channel 26 serving as an outlet channel. A first valve 27 serving as an inlet valve is arranged in the first channel 25. A second valve 28 serving as an outlet valve is arranged in the second channel 26.

[0070] The particularity of the pump unit 10 of the invention lies in the design of at least one of the valves 27, 28. Both valves 27, 28 can be designed identically. They are self-controlled (differential pressure controlled) valves, so-called non-return valves.

[0071] The following description of the valve 28 applies correspondingly to the valve 27 .

[0072] First reference Figure 3 , wherein the valve 28 is shown in a rest position, ie closed. The arrows 29, 30, 31 indicating the flow direction are therefore shown in a crossed-out manner, since no fluid flow occurs.

[0073] The valve 28 includes a valve closing member 32 which is substantially mushroom-shaped and is preferably made in one piece from a resilient material, such as from Figure 3 The longitudinal section in FIG. 3 is clearly visible. A preferably straight shank 34 extends away from the approximately disk-shaped, preferably slightly dome-shaped head 33. The shank 34 rests with its distal end 35 against an abutment 36 which is immovably arranged in the channel 26.

[0074] The head 33 comprises a preferably slightly domed sealing surface 42 which faces away from the stem 34 and abuts against the valve seat 38. By way of example and preferably, the valve seat 38 is configured as an annular circular protrusion surrounding the inflow-side portion 39 of the passage 26. Outside the valve seat 38, the head 33 may have a cavity.

[0075] Valve 28 operates as follows:

[0076] like Figure 3As shown, the valve closing member 32 is held between a valve seat 38 on one side and an abutment 36 on the other side, with or without play. Figure 3 and Figure 4 In the embodiment of , the valve closing member 32 is held between the abutment 36 and the valve seat 38 without play. The passage 26 is thus blocked. The fluid does not flow in the flow direction indicated by the arrows 29, 30, 31. To clarify this situation, the arrows 29-31 are crossed.

[0077] If a sufficient pressure difference now arises due to the piston reducing the working volume 24, the fluid present in the working volume 24 pushes the head 33 away from the valve seat 38, wherein the head 33 can be slightly deformed because its edge is warped towards the annular region of the channel 26. As a result, the shank 34 is reliably held in the support structure 40 which is immovably arranged in the channel 26. Thus, the abutment 36 can form the bottom of a pocket-shaped or blind-hole-shaped cavity in which the shank 34 is located and can form the end of the, for example, pin-shaped support structure 40 facing the head 33. The face-side end of the support structure 40 facing the head 33 is preferably formed by a face 41 against which the head 33 can abut if the shank 34 is pressed.

[0078] like Figure 4 As shown, the dome-shaped sealing surface 42 of the head 33 facing the valve seat 38 rises from the valve seat 38 and opens a flow path for a fluid, in particular a liquid. As a result, the stem 34 can be slightly compressed and the head 33 can be slightly deformed. The arrows 29, 30 show the direction of the flow through the annular flow cross section of the channel 26 and thus around the support structure on the outside. The flow indicated by the arrows 29, 30 flows from the head 33 into the annular cross section of the channel 26 and thus not radially inwards towards the stem 34 in any case.

[0079] Since the stem 34 is held securely in the support structure 40 and the fluid does not flow along the stem 34, the valve closing member 32 is not carried away from its seat by the flow into the channel 26 and thus remains operable also in the case of high flow rates. On the other hand, it already reacts to slight pressure differences and thus also allows the regulation of low-effect sizes which need to operate at very low flow rates. Furthermore, the valve described so far is also suitable as an inlet valve ( Figure 2 Due to the lower pressure difference required to open the valve, it is very suitable as a suction valve and can suck in liquid, also if the cylinder 11 or 12 is first filled with air only.

[0080] Independent of the specific configuration of valve 27 or 28, valves 27, 28 are preferably arranged one above the other, such as Figure 5As shown. Therefore, the upper valve 28 is used as an outlet valve, while the lower valve 27 is preferably used as an inlet valve. Therefore, the lower cylinder 12 includes a first valve 27' as an inlet valve and a second valve 28' as an outlet valve. Therefore, the channel 26 is connected to the two outlet valves 28, 28', and the outlet valves 28, 28' are connected to the corresponding cylinders 11, 12 at the top. Figure 7 As particularly shown in FIG. 2 , the channel 26 preferably leaves the respective cylinder 11 or 12 in the immediate vicinity of the wall 22. However, the position of the first valve 27 is dependent.

[0081] According to this concept, the pump unit 10 can be particularly easily ventilated. The air contained in the cylinders 11, 12 is easily removed by the pumping movement of the respective pistons and pushed out through the channel 26.

[0082] When the two valves 28, 28' are open in the same channel 26 rigidly formed in the cylinder head 13, the first channel 25 serving as liquid inlet can be accessed separately via a connecting structure 43, for example in the form of a fluid socket. This is independent of other construction applications 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' of the first valve 27' leading to the second cylinder 12 can be opened at 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 channels 25, 25', respectively, in order to fill the two cylinders 11, 12 with different liquids and thus supply different liquids to the same instrument. However, as Figure 1 and Figure 5 As shown, it is also possible to construct together a coupling piece 44, for example of flexible plastic, which comprises an internally bifurcated channel and which opens out on two plugs 44, 44' which can be inserted into the connecting structures 43, 43'.

[0083] Figure 8 A modification of the valve 28 (or 27) is shown which is independent of other configurations of the pump unit 10. It can be configured as described above or can also deviate therefrom. Unlike the valve 28 described above, Figure 8 The valve 28 shown 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 valve closing member 32 measured in the same direction. Therefore, the position of the valve closing member 32 is uncertain under pressureless conditions. However, in order to make the head 33 of the valve closing member 32 abut against the valve seat 38 or force it away from the valve seat 38, the slightest movement of the liquid is sufficient. The large umbrella-shaped head 33 thus enables a reliable switching of the valve closing member 32 in the closed position or in the open position, depending on the flow direction.

[0084] Also in this embodiment of the valve 28, the handle 34 of the valve closing member 32 is securely held in the support structure 40, and the surface of the support structure 40 facing the head 33 again forms a support surface 41, on which the head 33 can be supported if the valve 28 moves in the open position. Figure 8 The valve 28 shown is used as an outlet valve. In this configuration, it can also be used as an inlet valve. Figure 3 or Figure 4 For example, it is possible to construct the two valves 27, 28 identically. If desired, both valves 27, 28 can be configured according to Figure 8 In addition, it is possible to construct Figure 8 The valve, for example the first valve 27, is constructed according to the example of Figure 3 and Figure 4 The second valve 28 is constructed as an example of, and vice versa.

[0085] Figure 6 The configuration of the piston 21 and the designated cylinder 11 is shown. 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 (pump section) having a length L1, wherein it has a diameter D1. A second section 46 (sealing section) having a length L2 and a diameter D2 adjoins the first section 45. Therefore, the diameter D2 is preferably at least slightly larger than the diameter D1. Between the sections 45 and 46, a short conical tapering section can be provided, wherein the wall 22 transitions from the diameter D2 to the diameter D1. Therefore, the length of the second section L2 is preferably at least as large as the length L1.

[0086] The piston 21 comprises a sealing body 47 which seals with the wall 22 and comprises a rounded lip directed radially outwards for this purpose. The piston 21 comprises a non-circular (e.g., cross-shaped) cross-section in a region extending away from the sealing body 47. In a distance L3 measured from the face of the sealing body 47, the piston 21 comprises a disc-shaped section 48 adjoined by the piston rod 17. The disc section 48 is provided with a seal 49, such as an O-ring seal, a lip seal, etc., which seals with the cylinder wall 22. During the appropriate backward and forward movement of the piston 21, i.e., during the execution of 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 disc section 48 including its seal 49 moves only in the second section 46. While the piston 21 with the sealing body 47 delimits the sterile working volume 24 , the seal 49 of the disk section 48 reliably keeps environmental bacteria away from the area enclosed between the sealing body 47 and the seal 49 , so that the sterility of the wall 22 in the first section 45 can be ensured.

[0087] The pump unit 10 of the present invention includes at least one improved valve 28 (or 27), wherein the non-spherical valve closing member 32 is reliably maintained in the supporting structure 40, and wherein the supporting structure 40 is surrounded by external flow. The handle 34 of the valve closing member 32 is maintained in the bag-shaped seat of the supporting structure 40, so that the valve closing member 32 is also reliably maintained in place under the condition of large flow. For this purpose, the supporting structure 40 is only surrounded by external flow. The handle 34 is located in a receptacle, which is formed in the supporting structure 40, such as in the form of a blind hole, and no flow passes therethrough. Preferably, the pump unit is provided with two cylinders 11, 12, which are arranged in a flat manner, so as to be arranged vertically up and down each other. However, in particular, the first valve 27 and the second valve 28 are preferably arranged up and down each other. Thus preferably, the second valve 28 assigned to the outlet channel is arranged adjacent to the cylinder wall 22 at the vertical highest point of the cylinder wall 22. This simplifies the ventilation of the pump unit 10.

Claims

1. A pump unit (10), in particular for medical use, in particular for water jet surgery, having at least one cylinder (11) in which a piston (21) is displaceably supported, A first passage (25) connected to the cylinder (11) is provided, wherein A first valve (27) is arranged in the first channel (25), the first valve having a first valve closing member (32') assigned to a first valve seat (38'), having a second channel (26) connected to the cylinder (11), wherein a second valve (28) is arranged in the second channel (26), the second valve having a second valve closing member (32) assigned to a second valve seat (38), It is characterized in that The first valve (27) serves as an inlet valve and the second valve (28) serves as an outlet valve, and the first valve (27) and the second valve (28) are arranged one above the other, wherein the second valve (28) is arranged above the first valve (27).

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

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

4. The pump unit according to claim 1, characterized in that At least one of the valve closing members (32) is seamlessly integrally constructed of an elastic material.

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

6. The pump unit according to claim 1, characterized in that At least one of the valve seats (38) is an annular rib-like protrusion surrounding the inlet opening.

7. The pump unit according to claim 1, characterized in that At least one of the valve closing members (32, 32') includes a resilient handle segment (34) retained in a support structure (40) through which no flow passes, and the resilient handle segment is opposite to a valve seat (38, 38'), and at least one of the valve closing members (32) includes a head segment (33), the resilient handle segment (34) extending away from the head segment.

8. The pump unit according to claim 7, characterized in that The shaft section (34) is designed to be straight and pressure-elastic.

9. The pump unit according to claim 7 or 8, characterized in that At least one of the valve closing members (32) is held in a play-free manner between an abutment (36) formed on its supporting structure (40) and the valve seat (38).

10. The pump unit according to claim 9, characterized in that The support structure (40) is arranged in such a way as to surround the handle section (34).

11. The pump unit according to claim 10, characterized in that The support structure (40) is arranged in the channel (26) and defines, together with the wall of the channel, an annular flow cross section.

12. The pump unit according to claim 1, characterized in that The utility model comprises two cylinders (11, 12) which are respectively arranged in a horizontal manner.

13. The pump unit according to claim 12, characterized in that The two cylinders (11, 12) are arranged vertically above each other.

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), wherein the second section (46) has a diameter (D2) that is greater than a diameter (D1) of the first section (45).

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, and the seals seal the piston (21) against the cylinder (11, 12).

16. The 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 a maximum pump stroke of the piston (21).

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