WO2000078377A1

WO2000078377A1 - Mechanically operated liquid pump

Info

Publication number: WO2000078377A1
Application number: PCT/DE2000/001933
Authority: WO
Inventors: Roland Wex
Original assignee: Roland Wex
Priority date: 1999-06-19
Filing date: 2000-06-19
Publication date: 2000-12-28
Also published as: DE10081671D2; EP1187645A1; DE19928131A1; JP2003502563A; DE19928131C2; AU6425000A

Abstract

The invention relates to a mechanically operated liquid pump, in particular, for medicinal or physiologically nutritional liquids. According to the invention, the pump has the following features: a pouch (1) for receiving the liquid (2), a line (3) which is connected to the pouch for discharging the liquid therein out of said pouch, a device (9 to 14) for exerting a compressive force on the pouch for discharging the liquid therein, whereby the device for exerting said compressive force has an elastic element (10) which acts upon one side of the pouch and an additional element (11, 13) which acts upon the opposing side of said pouch. A mechanically operated liquid pump of this type has an extremely simple construction, is cost-effective to produce and also has a universal application.

Description

Mechanically operated liquid pump

Description

The invention relates to a mechanically operated liquid pump, in particular for medical and nutritional liquids.

A wide variety of types of liquid pumps are used in connection with the conveyance of medical and nutritional fluids. Pumps operated for example electro-energetically, electrochemically, gaseously, mechanically, electromechanically and mechanically-physically are known. As a rule, many of these pumps can only be used after a longer start-up time and often offer the user and consumer inadequate dosing accuracy. The known pump systems are otherwise quite expensive and not very advantageous from an ecological point of view. Often they cannot be used by the user in a portable manner.

A liquid pump for medical purposes is known from practice ("Accufuser", medac gmbh, Hamburg), which has an elastic bag which is provided with an inlet and outlet line. The outlet line leads to the patient, while the access line serves to fill the elastic pouch with a liquid medication. When the bag is filled, it expands and empties under the action of the restoring force of the elastic bag and the gravity of the liquid. A flow limiting valve is arranged in the outlet line to the patient. The bag has a volume between 60 and 100 ml. - Such a pump is quite complex to put into operation because the bag must be stretched when filling. Since the flow rate of the liquid results solely from the resilience of the elastic bag, the liquid can only be dispensed with low pressure. Since only the elastic wall of the bag acts on the medical liquid, it is not ensured that the liquid is pressed out of the bag with largely the same pressure and that the bag is emptied completely. The design principle of this pump makes it necessary to use the flow regulator.

A liquid pump for medical liquids is known from practice ("SmartDose ^" ", Pro-Med GmbH, Linz, Austria), in which a container holding the liquid is connected via a channel to a reaction space in which a carbon dioxide cell is accommodated. When this cell is activated, carbon dioxide evolves, which pressurizes the liquid in the container to be dispensed and a regulator valve ensures that a substantially constant amount of liquid is dispensed from the container per unit of time.

A mechanically operated liquid pump for medical liquids is known from US Pat. No. 5,334,197, in which a chamber for receiving the liquid is only acted upon mechanically and the contents of which are thereby pressurized to dispense the liquid. The chamber is formed by a thin wall and an expandable wall, this wall being connected to a leaf spring. Before using the pump, the leaf spring is held in a cover, which thus fixes it in a defined shape. If the cover is removed from the leaf spring, the spring element snaps over into a position in which it is bent toward the elastic wall. As a result, the elastic wall is stretched by the liquid in the chamber, in a shape that corresponds to the curvature of the snap-on leaf spring. Under the pressure of the stretched elastic wall, the liquid is discharged from an outlet line connected to the chamber, the elastic wall becoming increasingly closer to the arched leaf spring until the chamber is completely emptied. - Such a liquid pump can be operate exclusively mechanically, but has a large number of parts and a very high production cost. User handling is quite complicated.

Compared to the prior art, it is an object of the invention to provide a mechanically operated liquid pump that is structurally simple in design and can be produced particularly inexpensively, and which can therefore be used universally.

The object is achieved by a mechanically operated liquid pump, in particular for medical and nutritional liquids, which has a bag for holding the liquid, a line connected to the bag for dispensing the liquid in the bag from the bag, and a pump Device for exerting a compressive force on the bag for dispensing the liquid therefrom, the device for exerting the compressive force having an elastic element for acting on one side of the bag and a further element for acting on the opposite side of the bag.

Such a mechanically operated liquid pump is extremely simple. It has the bag with the liquid which is acted upon by the device for exerting a compressive force on the bag. The essence of this device can be seen in the fact that at least a partial area of the device has an elastic element for acting on the bag, thus pressing the bag against its counter-support from this side. This counter-support, generally referred to as an element for acting on the opposite side of the bag, is advantageously rigid, so that the elastic element presses the bag against the rigid element. However, it is equally conceivable to provide a further elastic element instead of the rigid element, with which the bag would be held between two stretched-out elastic elements which have the tendency to relax on one another and thereby press liquid out of the bag. For example, the device for exerting a compressive force has a pressure plate which acts under the action of a spring element and which represents the element for acting on the opposite side of the bag. The active pressure forces on the bag are thus not only applied by the elastic element but also by the spring element. The action of the spring element ensures in particular that the bag can be completely emptied, since when the elastic element is largely returned from its deflected position and consequently its pressure force is reduced, the spring element still acts on the bag with a defined pressure force . The spring element can be designed, for example, as one or more spiral springs which exert a compressive force or else as a leaf spring.

Due to the particularly simple design of the liquid pump according to the invention, it offers a wide range of uses. The user can use the pump anywhere immediately without long start-up times. It can be used by the user, as well as used statically, in all normal areas of life outside, like within medicine. It can be used sterilized and ensures minimal operation / handling. The pump is inexpensive to manufacture due to the simple design of the few components, which is a prerequisite for using it in particular in outpatient and financially weak markets. The low weight of the pump enables it to be used in accident, emergency doctor, hospital and catastrophe areas. The functional elements of the pump can be replaced individually or as a whole. The pump is suitable for short or long delivery times, for open or closed systems, for unfilled or prefilled infusion systems of different geometrical designs, in particular also in connection with the use as a micropump, i.e. systems from 1 to 10 ml.

The different sized bags that are used in the pump or the pump itself can be used once or reused several times. Depending on the selected elasticity of the elastic element, different flow rates and drain times can be achieved. The elastic element is designed in such a way that the liquid is squeezed out of the bag until the elastic element is in contact with the other element to act on the opposite side of the bag and in this state the bag is emptied, taking into account the resetting behavior of the Spring element. The pump according to the invention is independent of electrical energy. It can be used anywhere in the temperature range of at least 10 to 60 ° C. The raw materials used are biodegradable and regenerable. The pump is therefore environmentally friendly and, due to its simple design and construction, can be manufactured inexpensively in a small packaging size and offered to the market.

The pump can be used for different viscosities, for example for infusion, enteral nutrition, transfusion, etc. It can be used in all liquid application areas of small and medium flow rates in short or long times. The pump can be interrupted simply by deactivating the device for exerting the pressure force and can simply be restarted if necessary, in contrast to the pump according to US Pat. No. 5,334,197, in which extensive handling is necessary. If necessary, the pump can be equipped with a reusable electronic signaling device which indicates the end of the liquid transport or the emptying of the bag.

Further advantageous embodiments of the pump according to the invention are described in the subclaims. These relate in particular to a tenter frame as part of the device for exerting the compressive force, the tenter frame receiving the elastic element for acting on one side of the bag. The device for exerting the compressive force on the other side of the bag is expediently designed as a hard pressure plate which, in order to ensure complete emptying of the bag, is designed so as to be curved toward the elastic element. The two elements are preferably articulated by means of a hinge and can be closed by means of a snap connection. To ensure that the bag is permanently held firmly between the two elements, they should not only be closable on the side facing away from the hinge, but also in the side areas, in particular by means of a snap connection. Apart from the permanent connection in the area of the hinge, the two elements can thus also be connected to one another in the other areas.

According to a special development of the invention, it is provided that a flow valve interacts with the pump, which is connected to the pump output volume flow largely constant. This valve has a particularly simple design and is therefore adapted to the wide field of application of the pump. The valve preferably has a valve body located in a housing, which is provided with a liquid channel, the liquid pressure present in the valve acting on a pressure surface of the valve body and depending on the pressure present, the liquid channel is more or less compressed by deformation of the elastic valve body. This valve can be used for different flow rates. Although flow rates of> 1000 ml per hour are quite conceivable, a flow rate of 0.5 to 10 ml per hour is regarded as the preferred area of application.

Further features of the invention are shown in the description of the figures, it being noted that all the individual features and all combinations of individual features are essential to the invention.

The invention is illustrated in the figures on the basis of several embodiments, without being limited thereto. It shows:

FIG. 1 shows a view of a first embodiment of the infusion pump when the device for exerting a compressive force on an infusion bag is not activated,

FIG. 2 shows the embodiment according to FIG. 1 in a corresponding view with activated device for exerting the compressive force on the bag,

3 shows a longitudinal central section of the valve used in the pump variant according to FIGS. 1 and 2 for largely maintaining the volume flow output by the pump,

FIG. 4 shows a view of a second embodiment of the infusion pump, viewed in the direction of the main surface, this infusion pump being provided with a valve for keeping the volume flow constant,

FIG. 5 shows a side view of the infusion pump shown in FIG. 4, as shown in FIG. 2,

FIG. 6 shows an end view of the infusion pump shown in FIGS. 4 and 5, FIG. 7 shows the infusion pump in a representation according to FIG. 2, but without a valve,

8 shows the infusion pump in a representation according to FIG. 5, but without a valve,

FIG. 9 shows a prefilled infusion system using an inventive fluid pump designed as a micropump, in a first view (according to arrow Y in FIG. 10),

10 shows the infusion system according to FIG. 9 in a second view (according to arrow Z in FIG. 9),

FIG. 11 shows the infusion system shown in FIG. 10, when the device for exerting the compressive force on the infusion bag is not activated,

12 shows an embodiment modified from the embodiment according to FIG. 1 and

FIG. 13 shows an embodiment modified compared to FIG. 4.

The embodiment according to FIGS. 1 to 3 differs from that according to FIGS. 4 to 6 only in that the bag 1 used for receiving the medical and nutritional fluid 2 does not only have a line 3 for dispensing the liquid from the bag 1, but , as in the embodiment according to FIGS. 4 to 6, also has a line 4 for feeding the liquid into the bag 1. The bag 1 can thus be refilled via the line 4, making this pump system usable several times. Both embodiments have a valve 5 connected to the outlet line 3, which serves the purpose of additionally ensuring that the volume flow output by the pump is kept largely constant. With regard to the design of the pump, reference should also be made to the representation of FIGS. 4 and 6 with regard to the embodiment according to FIGS. 1 and 2, and additionally to the representation of FIGS. 1 and 3 with respect to the embodiment according to FIGS.

The bag 1 is formed from two foils which are welded together in the region of the peripheral edge. The respective film has an essentially rectangular surface. The bag 1 is filled with the medical liquid 2 so that it is on its main surface seen, has a substantially rectangular shape. In the area of the middle of a narrow side of the bag, the line 3 goes from the bag. The line end is provided with a Luer lock connector 6 which interacts with a complementary Luer lock connector 7 of the valve 5. A cannula 8 goes from the valve 5 to the vein, not shown, of a patient's arm. A butterfly cutlery can optionally be provided in the area of the cannula 9.

The infusion bag, which is preferably made of PVC, in particular has an infusion volume of 1, 2, 5 or 10 ml.

As can be seen from the illustration in FIGS. 1, 2, 4 and 6, the device for exerting a compressive force on the bag 1 for dispensing the liquid from the latter has a tensioning frame 9 in which an elastic film is located on the side facing the bag 1 10 is held by being glued to the tenter 9, for example. The tenter 9 is in accordance with the outer design of the bag

I formed rectangular. It is mounted in the manner of a hinge 12 in a hard pressure plate 11, which has a rectangular design corresponding to the clamping frame 9. The hard pressure plate

II is provided on its side facing the stenter 9 with a curvature 13 directed thereon. On the side facing away from the hinge 12, thus in the area of the other narrow side, the hard pressure plate 11 is provided with two locking lugs 14 which engage behind the corresponding narrow side of the tensioning frame 9 when it is pivoted onto the pressure plate 11. The curvature 13 of the pressure plate 11 extends over the entire width of the opening in the clamping frame 9.

When the tensioning frame 9 moves away from the pressure plate 11, as shown in FIG. 1, the filled bag 1 of the individually usable infusion pump is placed between the pressure plate 11 and the elastic film 10 held in the tensioning frame 9. Then the clamping frame 9 is pivoted in the direction of the pressure plate 11 and the two parts are connected to one another in a latching manner by the two latching lugs 14 engaging behind the end face of the clamping frame 9. When the pressure plate 11 and the film 10 are moved towards one another, the bag 1 lying against the film 10 presses the film from its plane into the arched position shown in FIG. 2 in the locked state of the pressure plate 11 and the clamping frame 9. Due to the flat force exerted on the bag 1 by the elastic film 10, the liquid is conveyed through the line 8 and the valve 5 to the cannula 8 in accordance with the resilience of the elastic film 10. The conveying process can be interrupted in a simple manner by releasing the latching connection 14 and moving the clamping frame 9 into the open position.

FIG. 3 illustrates the valve used in the pump according to the invention for keeping the volume flow output by the pump largely constant. The valve consists of a lower housing part 15, a valve body 17 inserted therein and an upper housing part 16. The lower housing part 15 and the upper housing part 16 are made of plastic and are designed as injection molded parts. The valve body 17 consists of an elastic material with an adjusted modulus of elasticity, so that the valve body 17 can change its shape and thus its passage cross section if the pressures in the bag 1 change, if necessary. The lower housing part 15 passes through an inflow channel 18, the upper housing part 16 through an outflow channel 19. The connector 20 assigned to the inflow channel 18 is provided with the connection 7, which has an external thread 21, so that the valve 5 in this area has the complementary internal thread having Luer lock connector 6 can be connected. The nozzle 22, to which the drainage channel 19 is assigned, is surrounded by a ring extension 23 which is provided with an internal thread 24. In this area the valve 5 can be connected to the cannula 8, which has a plug with an external thread. The upper housing part 16 is provided on its side facing the lower housing part 15 with a stepped cylinder chamber into which a cylinder extension 25 of the lower housing part 15, to which the inlet channel 18 is also assigned, is fitted. Here, the end face 26 of the cylinder extension 25 contacts the facing outer end face 27 of the valve body 17, which is designed as a ring. The cylinder extension 25 can slightly compress the elastic valve body 17. The lower housing part 15 and the upper housing part 16 are connected to one another as desired, for example welded, glued or screwed. The valve body 17 has on its side facing the lower housing part 16 an annular recess 28 which has the function of a liquid pressure chamber. Radially within the annular recess 28, a pressure remains in the valve body 17 flank section 29, which is designed, for example, as a truncated cone. In the central axis of rotation of the valve body 17, the pressure flank section 29 has a liquid channel 30 which completely penetrates the valve body 17. The thickness of the pressure flank section

29, the radially outer sealing flank wall 31, the valve body base 32 facing the upper housing part 16 and the diameter of the liquid channel 30, and the elasticity of the valve body 17 are coordinated with one another with regard to the desired flow rate. Specifically, the liquid channel 30 is matched to a minimum flow rate. If the pressure upstream of the valve body 17 increases, it causes the valve body base 32 to be compressed more. Furthermore, the sealing flank wall 31 presses more strongly against the upper housing part 16. Because of the design of the frustoconical pressure flank section 29 surrounding the liquid channel 30 and the resulting pressure force component perpendicular to the longitudinal direction X of the liquid channel

30, directed towards the latter, the diameter of the liquid channel 30 is reduced, at least in the region of the pressure flank section 29. When the pressure of the liquid in the valve increases or the same decreases, the liquid flow A through the valve is kept largely constant.

With regard to the description of the embodiment according to FIGS. 4 to 6, reference is made to the above explanations. In the embodiment of the pump according to FIGS. 4 to 6, the access line 4 to the bag 1 is provided with a Luer lock connection 33 which can be closed. Via this connection 33, after unscrewing the closure, the bag 1 can be refilled, for example by means of a syringe. After the connection has been closed, the bag can then be inserted between the clamping frame 9 and the pressure plate 11 in the same way as in the embodiment according to FIGS. 1 and 2 and can be pressurized by applying the elastic film 10.

The embodiment according to FIG. 7 corresponds to the embodiment according to FIG. 2, the embodiment according to FIG. 8 of the embodiment according to FIG. 5, each with the difference that the embodiments according to FIGS. 7 and 8 have no valve 5. The use of this valve is only required if it is on the Maintaining a fairly constant volume flow when dispensing the liquid from the bag 1 arrives.

FIGS. 9 to 11 show a prefilled infusion system using a micropump, in which the bag 1 has a capacity of 1 to 10 ml. In this infusion system, the pump 34 designed according to the above-described embodiments is connected on the inlet side to an injection piece 35 and on the outlet side to the valve 5. A hose 36 connects the valve 5 to a butterfly system 37, to which a cannula 38 is connected. A protective cap 39 can be plugged onto this. The pump 34 or the butterfly system 37 can be attached to the patient by means of plasters 40 and 41. The direction of flow in the system is illustrated by arrow A.

The embodiment according to FIG. 12 differs from that according to FIG. 1 only in that the pressure plate 11, which is flat in the exemplary embodiment and comes into contact with the bag 1, by means of a plurality of compression coil springs 42 in a plate-shaped pressure plate receptacle 11a. This has the hinge 12 and one or more locking lugs 14 for connection to the tensioning frame 9.

The embodiment according to FIG. 13 differs from that according to FIG. 4 only in that the pressure plate 11 or the pressure plate receptacle 11a is not only provided with latching connections 14 in the area opposite the hinge 12, but also in the lateral areas of the rectangular tenter frame 9.

Claims

Patent claims

1. Mechanically operated liquid pump, in particular for medical and nutritional liquids, characterized by the following features: a bag (1) for receiving the liquid (2), a line (3) connected to the bag (1) for dispensing the in the bag (1 ) liquid (2) from the bag (1), a device (9 to 14) for exerting a compressive force on the bag (1) for dispensing the liquid (2) therefrom, the device (9 to 14) for exerting the compressive force is an elastic element (10) for acting on one side of the bag and another element (11) for acting on the opposite side of the bag.

2. Pump according to claim 1, characterized in that the device (9 to 14) for exerting the compressive force has a clamping frame (9) which receives the elastic element (10) for acting on one side of the bag.

3. Pump according to claim 1 or 2, characterized in that the device (9 to 14) for exerting the compressive force has a hard pressure plate (11) which represents the element (11) for acting on the opposite side of the bag.

4. Pump according to claim 3, characterized in that the pressure plate (11) is curved in the direction of the elastic element (10).

5. Pump according to claim 3 or 4, characterized in that the means (9 to 14) for exerting a compressive force under the action of at least one spring element (42) has a pressure plate (11) which is part of the element (11) for acting represents the opposite side of the bag.

6. Pump according to one of claims 1 to 5, characterized in that the two elements (9, 11) are connected by means of a hinge (12) and can be closed at least on the side facing away from the hinge (12), in particular by means of a latching connection ( 14).

7. Pump according to claim 6, characterized in that the two elements (9, 11, 11a) on the side facing away from the hinge (12) and the side areas can be closed, in particular by means of latching connections (14).

8. Pump according to one of claims l to 7, characterized in that the elastic element (10) is designed as a film (10) which is held on the edge side in the clamping frame (9).

9. Pump according to one of claims 3 to 8, characterized in that the pressure plate (11) and the clamping frame (9) are rectangular, in particular have a similar rectangular shape and rectangular area, and the clamping frame (9) has a rectangular opening for Inclusion of the elastic element (10).

10. Pump according to claim 9, characterized in that the shape of the bag (1) corresponds approximately to the shape of the tenter (9).

11. Pump according to one of claims 1 to 10, characterized in that with the line (3) for dispensing the liquid (2), a valve (5) is connected to keep the volume flow output by the pump largely constant.

12. Pump according to claim 11, characterized in that the valve (5) has a housing (15, 16) and a valve body (17) received by the latter, which is provided with a liquid channel (30), the valve body (17 ) is designed as an elastic closing body with an outer pressure surface (29) and on the pressure surface of the upstream of the valve body (17) effective pressure with a pressure force component perpendicular to Longitudinal direction (X) of the liquid channel (30), directed towards it, acts.

13. Pump according to claim 12, characterized in that the valve body (17) has on its upstream side a pressure flank section (29) which has the outer pressure surface (29), the liquid channel (30) the pressure flank section (29) enforced.

14. Pump according to claim 13, characterized in that the pressure flank section (29) is designed as a truncated cone, cylinder, truncated cone with cylinder extension or the like, the liquid channel (30) being arranged in the axis of rotation of the pressure flank section (29).

15. Pump according to one of claims 12 to 14, characterized in that the valve body (17) rests with its radially outer on the wall of the housing (15, 16) and there has an annular shoulder (31) on which the upstream of the valve body (17) effective pressure with a compressive force component perpendicular to

Longitudinal direction (X) of the liquid channel (30), directed away from it, acts.

16. Pump according to one of claims 1 to 15, characterized in that the valve (5) is provided with a liquid filter.