DE3939367A1 - DISPLACEMENT PUMP - Google Patents

Description

Background of the Invention

Most positive displacement pumps - that is, pumps that have a variable volume pumping chamber that has a movable displacer element - deliver and remove fluid through orifices that open to the chamber through an immovable chamber wall. The inlet and outlet ports usually have one-way valves, such as. B. ball check valves or flap valves. Because of the limited space available for the openings and the fact that the limiting factor in pump capacity is usually in the line to or from the pump rather than in the pump itself, the inlet and outlet openings are relatively small . The small size of the openings limits the intake and exhaust flow rates, causes pulsating inflow and outflow, and consumes energy in the form of dynamic fluid friction and turbulence losses. The relatively small size of the inlet openings in most pumps also requires a relatively high pressure difference between the inlet and the pump chamber in order to ensure filling during the suction stroke.

The inventor of the present invention has several years long considerable work in the development of blood pumps spent on the anatomical heart when pumping blood through to replace or support the blood vessel system. There is some properties that are required for blood pumps and not are easy to accomplish. First, it is desirable that one mechanical blood pump is capable of blood essentially to bring in continuously, preferably with minimal Pulsation. Second, a mechanical blood pump should be in the Be able to automatically adjust their emissions based on feed changes  a fairly wide range. Third, one must Blood pump, which has the valves as far as possible from "Dead dreams" should be free, spaces where there is little or no Current gives and where consequently blood collects and clots can form; the blood must always be in motion in the pump being held. Fourth, a blood pump must be sterile and free of toxic materials when put into use and it has to stay that way as long as it is in use located.

Mechanical blood pumps for temporary use, such as B. during heart surgery, or to support a damaged heart for a short while as it heals are increasingly used. The ones currently in use mechanical heart pumps meet the recognized requirements only partially. For example, you have little ability automatically changes in body blood requirements adjust, and instead need to be closely monitored and to be controlled. Current mechanical blood pump systems require a relatively large amount of the patient's blood flowing outside of the body and a lot of blood like that, which flows outside of the patient's body must become what is undesirable.

Lundbäck describes one in US Pat. No. 4,648,877 (March 10, 1987) Blood pump and shows this which is very effective the previous one mentioned requirements met. The pump known hereafter has a supply chamber (atrium) and a pump chamber (ventricle), which by a short passage with a one-way valve connected is. The chambers are made of a flexible, essentially Lichen not stretchable material and can be quite are inexpensive to manufacture and can therefore be used len from different patients outside the body be replaced. A drive ring is turned on in one direction  driven to reduce the volume of the pumping chamber, d. H. around Pump blood out of the pumping chamber and it will counter in the set direction moves depending on the supply of blood the inflow of blood from the supply chamber. The Construction of the pump according to the Lundbäck patent is such that it there are no dead spaces where the current is relatively calm and Blood can collect and form clumps. There are riverbeds restrictions minimized, but the pump has three relative small openings, two of which have a one-way valve.

Summary of the invention

An object of the present invention is to provide a positive displacement pump, the low hydraulic flow loss Has.

The object of the present invention is to reduce the pressure drop to make the pump approval minimal and therefore quick Ensure flow to the pumping chamber, even with a very small differential pressure across the inlet to the pumping chamber.

A supplementary object of the present invention exists in it, the pulsation of the flow upstream from the pump to be minimized both when the inlet is closed (a back pressure pulsation) as well as when it is open (on line pulsation). In this regard, it is desirable that disposable valves that are able to close reliably in the essentially without the need for a counterflow to be subject and without provoking one hen should be so that shocks or shocks from the Countercurrent result, can be avoided. It is intended also to provide for simplifications and the cost of pumps to minimize the number of parts, d. H. of all lines, chambers and valves through which the blood (or other fluid) flows and that is why preferably not reused  will. Another object is the creation of a pump, which automatically adjusts its output to the feed and requires a minimum amount of fluid within the pump.

According to the invention, the objects mentioned are obtained and are solved the task with a positive displacement pump in that the Pump according to the aforementioned US patent Lundback one Feed chamber has for receiving the fluid to be pumped, a variable volume pumping chamber, an inlet passage, through which the flow agent came from the feed chamber to the pump chamber mer is performed, and has an outlet through which the Fluid is drawn off or let out. A displacer part, which is assigned to the pump chamber, is in opposite set direction movable along a predetermined path so that it is a variable displacement zone of the Pump chamber moves to alternate the volume of the chamber increase and decrease. A drive mechanism moves the Displacement chamber in at least one direction to the volume to reduce the pumping chamber. An inlet valve closes the Inlet passage to allow fluid to flow back out of the pumping chamber blocked by the inlet passage.

According to the present invention, the feed chamber is in the generally arranged transversely to the displacement zone of the pump chamber and substantially surrounds it and the inlet passage runs essentially with the feed chamber and opens to the pumping chamber through an elongated, gap-like opening in a boundary or edge wall of the pump chamber, which is transverse to the displacement supply zone is arranged, whereby fluid into the pumping chamber the inlet passage substantially without any loss of pressure can occur. The pump chamber preferably has a movable ches part of the wall, which from the displacement part at Ejection stroke can be brought into engagement and from the displacement part is so disengageable during the intake stroke that the  Stroke volume of the pump by the incoming flow of the Fluid is formed through the inlet passage. Is common it is advantageous to make the pump chamber generally round (circular or oval) with a diameter that is essentially chen is greater than the height.

According to another aspect of the invention, a wall of the Pump chamber transverse to the direction of movement of the displacement part a flexible material is formed and is from the displacement partially engaged and through the displacement zone through this arched or bent to the volume to decrease the chamber. One wall of the inlet passage can also consist of flexible material and can preferably with the transverse wall of the pump chamber consist of one piece. A form of the inlet valve has a movable pinch valve part, which engages with the flexible wall at the inlet passage occurs and engages across the inlet passage the opposite wall or with a flap valve, which closes the opening. Alternatively, it can Inlet valve to be a flap made of flexible material one of its edges on a wall of the inlet passage is brought and the other end is free such that it is open the fluid flow and / or the pressure responds by opening when Intake stroke of the pump chamber and closing during the pump stroke Engaging with the other wall of the passage or through Engaging a similarly flexible flap on the other Wall of the inlet passage is attached.

In some embodiments, the pump chamber has an outlet in in the form of a gate or opening, and an outlet valve for the outlet opening from the flexible pump chamber wall and a movable valve part that uses the flexible wall engages with the outlet opening and thereby it closes. Other embodiments of valves, such as. B.  Flap valves can be used at the outlet from the pump chamber will. It is also possible to omit an exhaust valve entirely.

Advantageously, the feed chamber, the inlet corridor and the pumping chamber through two sheets or arches, panels, thin plates or thin layers made of flexible material, which are held by these fixed or rigid support parts, as they are required to carry weight and strength endure due to pressure. The material layers are preformed to the walls of the pumping chamber, supply chamber and the inlet passage to form, and are sealingly connected on their outer circumferences the. The fixed support parts define the designs maximum volumes of the chambers and shape the inlet opening to the pumping chamber.

The preferred ring and circular shapes of the feed chamber and Pump chamber ensure that the flexible bends or bulges Wall of the pumping chamber with a minimum of creases and ensure a uniform flow of fluid radially in into the pumping chamber. Because an outlet axially opposite Displacement part is arranged, a uniform outflow tion radially and then axially ensured. With the circular shape the flow through the pump takes place with low turbulence veaus but at relatively high speeds, without calm Areas.

The invention also has embodiments with a chamber the second stage with variable volume, which is the fluid from the pumping chamber during the discharge stroke of the latter records. Part of the fluid coming from the pumping chamber is discharged during its exhaust stroke, passes through the chamber the second stage to an emptying pass during which Rest during the second stage chamber suction stroke is introduced, preferably the operation in opposite phase  to the pumping chamber is going on. In this way, fluid from the Pump drained substantially continuously, i.e. both during the intake and the exhaust stroke of the second Level, and pulsations during ejection are reduced.

The preferred chamber element - preformed layers of flexible material that are sealed together at their peripheries - can be produced at low cost and is easy to install in a support structure. It is therefore economically and practically advantageous for the chamber element to be a disposable component.

Further advantages, features and possible applications of the present invention result from the following description Practice of preferred embodiments in connection with the Drawings. In the

Description of the drawings

shows

Figs. 1A to 7A generally schematic cross-sectional views of seven embodiments of single stage pumps shown in their configurations during the intake stroke; Figures 1B to 7B are generally schematic cross-sectional views of the respective embodiments of Figures 1A to 7A shown during their exhaust strokes;

Fig. 6C is a plan view of the Kanmerelement the execution form of Figures 6A and 6B.

FIG. 7C is a schematic cross-sectional view of the execution form of Figures 7A and 7B at the end of the induction stroke.

Figs. 8A and 8B are schematic cross sectional views of a two-stage pump according to the invention in different operating conditions;

FIGS. 9A and 9B are views similar to Figures 8A and 8B showing a modified two-stage pump.

FIG. 10A and 10B are schematic cross-sectional views of a further two-stage pump of the invention at differing operating conditions in accordance with Chen and 9A, 9B states corresponding in Figures 8A, 8B shown. and

Fig. 10C is a plan view of the chamber element of the embodiment forms of Fig. 10A, 10B.

Corresponding parts of all embodiments are the same Reference number followed by a hyphen (-), and a number after the hyphen, which is the figure numbering corresponds, making the full number a distinction the special embodiment.

Description of the embodiments

In all embodiments shown in the drawings the surfaces which are in contact with the liquid to be pumped Come into contact, the inner surfaces of a disc-shaped, generally one-way circular or part-circular merelements with an inlet and an outlet and from one flexible but essentially not stretchable or not stretchable material made such. B. polyethylene, polyurethane ethane or another plastic film. Not with others Embodiments described may include some or all of these Surfaces, however, are surfaces that are more stationary and movable Pump elements made of metal, for example, are permanent Are parts of the pump. The chamber element also does not have to be circular be mig.

As shown in Figs. 1A, 1B, the pump has a housing having a fixed base member 10-1 and a removable or hinged top member 11-1. The disk-shaped chamber element is designated 12-1 and is arranged between the base part and the upper part. At its periphery the chamber element 12 1 has an inlet connection 13-1, and at its center it has an upstanding axial outlet connection 14 -1.

The element 12 -1 has an annular supply chamber 15 -1, in which the inlet connection opens 13 -1. Within the supply chamber is a pump chamber 16 -1, which along with the supply chamber 15 -1 through an inlet passage 17 -1 in the form of an endless, annular their side edge wall portion, other gaps or gap-like opening between the opposed element walls is in communication. The pumping chamber 16 communicates with the central outlet connection -1 14 -1 -1 18 through an outlet passage in communication, which is also formed by an endless annular gap.

The element 12 -1 may be made of any flexible material Herge provides be, which has the properties which are required for the particular use of the pump in each particular case. Of course, the material should be compatible with the fluid being pumped and sufficiently flexible, durable and difficult to stretch or elongate to withstand the pressure and mechanical and, if it is, thermal stress to which it is subjected.

The housing base 10 -1 supports various movable components on which the element 12 -1 rests and which brings about the pumping by their repetitive or cyclical movements. These components have a centrally arranged outlet valve part 20 -1 , which serves to open and close the outlet passage 18 -1 to allow the flow between the pump chamber 16 -1 and the outlet connection 14 -1 . The outlet valve member is movable vertically parallel to the central pump axis 21 -1 to give up its upward movement towards the opposite element walls against the housing top part 11 -1 to squeeze and thereby close the outlet passage 18 -1, and according to its downward movement the element walls the possibility move away so that the outlet passage is opened. The movements of the outlet valve member 20 -1 are derived from a lever 22 -1, which is actuated in turn by a cam or other suitable drive member (not shown) and an associated engine.

There is also a Einlaßquetschventilteil 23 -1, which operates in a similar manner as the outlet valve member 22 -1 to the inlet passage to open and close 17 -1. The Einlaßven tilteil 23 -1 is annular, and its upward and downward movements are derived from a lever 24 -1 , which in turn is operated in synchronism with the lever 22 -1 by a motor-driven cam (not shown).

Between the valve parts 20 -1 and 23-1 and opposite the pump chamber 16 -1 there is an annular displacement part 25 -1 which is vertically up and down by means of a lever 26 -1 and a cam driven by a motor (which is not shown) ) in a similar manner to how the valve parts are moved, in synchronism with it. The displacement part 25 1 is used by its upward movement to the lower Pumpkam chamber wall to displace and thereby reduce the volume of the pumping chamber 18- 1, and to allow the expansion of the pump chamber to its downward motion as soon as fluid stromt in the pump chamber.

There is in the embodiments of Figs. 1A and 1B, a pair of rollers 27 -1, which the element 12 -1 disposed below the feed chamber 15 1 and are engaged therewith. In operation of the pump, these rollers, of which there may be more than two, circle the circumference along the feed chamber by means not shown, in order to keep all the liquid in the feed chamber in constant motion. Such stirring of the liquid may be necessary or advantageous in certain applications, e.g. B. if the liquid is blood.

In operation of the pump, the supply chamber 15 -1 functions as a reservoir whose volume is changed depending on the flow coming in the liquid and which continuously ness under relatively low pressure through the inlet connection 1 accommodates 13-. In the phase of the pump cycle shown in FIG. 1A, where the inlet passage 17 -1 is open and the displacement part 25 -1 has moved down or has just reached its lowest position, liquid flows from the supply chamber 15 -1 into the pump chamber 16 - 1 through the inlet passage 17 -1 . The filling of the pump chamber can be done very quickly because the inlet passage is very long, ie it has a very large extent, and can be opened easily over a relatively considerable height. In other words, the inlet passage can be opened well to provide a very large cross-sectional area for the flow. Since the supply chamber and the inlet passage also surround most or all of the circumference of the pump chamber and fluid enters radially from all directions, the filling length, ie the distance by which the liquid has to flow in order to fill the pump chamber, is short and straight. whereby the flow into the pumping chamber can take place very quickly and essentially without pressure loss. Pumps with annular chambers can have large capacities and yet short filling times due to the large area of the inlet passage and the short filling length.

The filling of the pumping chamber 16 -1 is essentially "passive" - it takes place essentially only under the action of the hydrostatic head pressure prevailing in the supply chamber 15 -1 at the inlet passage 17 -1, because within the pump chamber no suction is produced as a direct Consequence of the downward movement of the displacement part 25 -1 ; the displacement member has no force-transmitting connection with the element 12 -1, which is effective in the direction of expansion of the pump chamber (downwardly).

It is within the scope of the invention to influence the filling by exerting the pressure within a gas body, which surrounds the pumping chamber during the pumping cycle in is caused to change in a special way. It is also possible to exert an influence on the filling by: subjects the inlet or supply chamber to external pressure.

As shown in Fig. 1B, the inlet passage 17 -1 is then closed by an upward movement of the inlet valve member 23 -1 , and the outlet passage 18 -1 is opened by a downward movement of the valve member 20 -1 . Then, the displacement part 25 -1 is moved upward to the lower wall of the pumping chamber to displace upward or to move and thereby to expel the liquid in the pump chamber 16 through the outlet passage 18 -1 1 and the outlet connection 14 -1. Meanwhile the supply chamber is replenished from the inlet connection 13 -1 15 -1. The outlet passage 18 -1 is then closed, the displacement part 25 -1 is withdrawn downward, and the inlet passage 17 -1 is opened again, so that another pumping cycle can be carried out.

A feature of the described pump resides in the combination of the annular inlet passage 17 -1, the annular outlet passage 18 -1 and the short filling length, which allows a very rapid filling of the pump chamber, even when the pressure on the inlet side is very low, and a very rapid emptying of the pump chamber allowed. The pump can therefore pump a large volume of liquid per unit of time with low internal losses and accordingly pump with a very high output. As long as the incoming flow to the pump does not exceed the flow speed, which corresponds to the product of the maximum stroke volume and the stroke speed, the pump adjusts the volume to be pumped for each stroke to the incoming flow by means of its self-regulation. Within a fairly wide range of incoming or Zuströmungsge speeds therefore through the inlet connection 13 -1, the pump provides a continuous influx of free Sieren of Druckpul and interruptions. If the inflow should exceed the flow rate corresponding to the above product, the speed or stroke speed of the pump can be increased. Because of the small internal losses, the lifting speed can be increased to high levels.

Another feature to be described, which pump is present in the described pump as well as in the and which helps to fill the pump chamber 16-1 quickly, based on the creation of a volumetric capacity or a Fas sungsvermögens the supply chamber 15 -1, which is sufficiently large - preferably substantially larger than that of the pumping chamber 16 -1 - a filling of the pump chamber 16 -1 ensure without it being necessary to fill the supply chamber 15 -1 during the filling of the pumping chamber is substantially again. Therefore, all the liquid which enters the pump chamber 16 -1 during the filling phase of the pump cycle, immediately close to the inlet passage 17 -1 available when the filling phase commences.

The element 12 -1 is arranged in the pump housing 10 -1 / 11-1 in such a way that the feed chamber 15 -1 can expand and contract freely within wide limits depending on the inflow of liquid to the feed chamber or the outflow of liquid the supply chamber to the pump chamber 16 -1 .

The embodiment of FIGS. 2A and 2B differs from that of FIG. 1A and 1B only in that the rollers 27 -1 are omitted and the supply chamber 15-2 is open to the atmosphere. Therefore, the pressure under which the filling of the pump chamber 16-2 takes place is, and the free liquid surface is determined in the supply chamber by the difference in level between the inlet passage 17 -2.

In the embodiment of Fig. 3A and 3B, the Zufuhrkam mer -3 15 is open as shown in Figs. 2A and 2B. One-way flaps or lip valves 23 -3 or 20-3 are provided in the inlet passage 17 -3 or the outlet passage 18 -3 . Accordingly, the movable pinch valve parts in the first two Ausführungsfor men are replaced by parts of the housing part 10 -3 , which support the chamber element and form the passages 17 -3 and 18-3 . Each valve 23 -3, 20-3 is formed of two annular, axially opposed flaps of flexible material (eg. As plastic) is formed, which also may be somewhat elastic, their outer edges sealed to the respective opposite element walls in the inlet passage 17 -3 (e.g. by heat sealing) which are free to deform and can therefore move up and down on their inner edges.

If the liquid in the inlet passage or in the outlet passage Flows inwards, the flaps are kept at a distance without noticeably resist or oppose the liquid flow as soon as the liquid has the tendency into the to flow in the opposite direction, the flaps close the Passage and block the flow. Unless the flaps are elastic, their elasticity is not so high that they are unable to reliably occur To withstand pressure and there is therefore no risk that the flaps turn in the wrong direction. If the Operating pressure of the pump is high, the flaps can suitable material are reinforced, e.g. B. glass fibers to them on To prevent tipping over or folding over or inverting.

The flaps can be designed so that by means of their  Elasticity, the initial shape or otherwise help to accelerate the flow of the liquid as soon as they are opened. Furthermore, they can be closed or be slightly biased towards the open position.

In a modified embodiment, not shown, one or both of the valves can combine a pinch valve of the type shown in FIGS. 1 and 2 with a flap. In such a case, the pinch valve is preferably arranged in order to only partially close the assigned passage and to leave it to a flap to complete the closing.

As shown in FIGS. 3A and 3B, the Klappenven tile are formed by a flap element, which is separate from the chamber element walls. However, the flaps can advantageously be formed from a fold in the position or in the film material from which the element is made, the formation of this fold taking place during the manufacture of the chamber element. The last-mentioned embodiment is itself suitable for production by means of known techniques for the production of elements and other plastic objects (vacuum molding and injection molding). The same design can also be used or incorporated in the embodiments described below.

The embodiment shown in Figs. 4A and 4B is similar to that of Figs. 1A and 1B except that the exhaust valve is arranged in the form of a one-way valve 20 -4 of flap or lip type and in the exhaust connection 14 -4 , and thereby that the displacement part 25 -4 is disc or plate-shaped (mushroom-like). In this case, the pump chamber 16 -4 is disk-shaped instead of ring-shaped in plan view, as in the previous embodiments. Also, the outlet passage 18 -4 ( Fig. 4B) is only formed near the end of the pump stroke, which is slightly different in shape and function from the previous embodiments.

The embodiment shown in FIGS. 5A and 5B differs from that of FIGS. 4A and 4B in that the rollers for stirring the liquid in the supply chamber 15 -5 are omitted, in that the inlet valve 23rd -5 has a single flap made of flexible material which is attached along its outer edge to the lower element wall and is movable to a position in sealing engagement with the upper element wall under the action of the pressure within the pumping chamber 16 -5 and thereby that the valve is omitted in the outlet line.

It has been found that a valve which closes to block the backflow in the outlet line is not required in certain cases, namely when the pump is operating at high stroke speeds. In such cases, the moment of the outgoing liquid flow is sufficient to allow the pumping chamber 16 -5 to be filled through the inlet passage 17 -5 even if the pumping chamber is open on the outlet side during suction.

FIGS. 6A and 6B show an embodiment similar to that of FIGS. 5A and 5B, except for the positioning and design of the outlet passage 18 -6, the outlet connection 14-6 and the associated outlet valve 20 -6.

The outlet connection 14 -6 is radial in this case and is arranged diametrically opposite the inlet connection 13 -6 . Accordingly, its upstream end is arranged on the circumference of the pump chamber 16 -6 and, like the inlet connection 13- 6, extends radially outwards. As a result, part, but only part, of the circumference of the element is not used for the feed chamber 15 -6 and the inlet passage 17 -6 , but the latter can still be very long.

In this embodiment, the outlet valve 20 -6 is a flap or lip similar to the inlet valve 26 -3 , and like the latter it is attached to a wall of the outlet passage 18 -6 , which is at the connection between the pump chamber 16 -6 and the supply chamber 15 - 6 is arranged (see Fig. 6C, which is a plan view of the chamber element 12 -6 ).

In the embodiment shown in FIGS. 6A, 6B and 6C, it may be advantageous to block or close the area of the feed chamber 15 -6 next to the outlet connection. The wall of the feed chamber should then be designed such that no pockets are formed in which the liquid to be pumped stagnates or may be forced to undergo abrupt flow direction changes in order to reach the outlet passage.

The outlet connection 14 -6 of the embodiment of FIGS . 6A, 6B, 6C need not necessarily be in alignment with the inlet connection, but may include a smaller or larger angle therewith. If necessary, the two connections can even be arranged side by side and essentially in parallel. However, it is essential that the inlet passage 17 -6 and its valve extend over the major part of the circumference of the pumping chamber.

FIGS. 7A, 7B and 7C show an embodiment is arranged in which a part of the annular supply chamber 15 -7 closer to the center of the element than the gap-like inlet passage 17 -7. In this case, the drive mechanism of the displacement part 25 -7 is a - not shown in detail - screw mechanism with ball bearing, the screw spindle of which has a rotationally fixed connection to the rotor 28 -7 of an electric motor, which is arranged in the base part 10 -7 of the pump housing .

It is clear from a comparison of FIGS. 7A, 7B, 7C that the movement of the displacement part 25 -7 in this embodiment has a direct influence on the shape and the volume of the feed chamber. As soon as the displacement part moves downward (“falls off”), see FIG. 7A, the volume of the supply chamber decreases, because the displacement part makes the supply chamber collapse, see FIG. 7C. The liquid in the supply chamber then flows into the Pumpkam mer 16 -7 together with the liquid passing through the inlet connection 13 -7 in the pump occurs. As soon as the displacement part is driven upwards and thereby the volume of the pump chamber is reduced, see FIG. 7B, the feed chamber is enlarged, and at the same time the inlet valve 23 -7 is closed. The liquid which then enters via the inlet connection is received in the feed chamber and then flows into the pump chamber after the subsequent downward movement of the displacement part, as described.

The embodiment shown in Figs. 7A, 7B, 7C also has an outlet valve 20 -7 which prevents backflow into the pump chamber 16 -7 from the outlet connection 14 -7 . As shown in the figures, the outlet connection is parallel to and diametrically opposed to the inlet connection, but other orientations and positions can also be considered.

The outlet valve 20 -7 is a valve with an annular flap, one peripheral edge of which is attached to the upper part 11 -7 of the pump housing and the other free peripheral edge of which is provided with a bead ring 29 -7 . This bead ring reinforces the free flap edge, and in the closed position of the valve ( Fig. 7C) it is sealingly engaged with the inner wall of the upper part 11 -7 of the housing. As an alternative to the illustrated embodiment of the outlet valve, a resiliently biased, vertically movable valve part can be provided which seals against an annular wall part where the pumping chamber merges into the horizontal outlet connection.

The inlet valve 23 -7 of the embodiment shown in FIGS . 7A, 7B, 7C is also a valve with an annular flap which is attached to the displacement part and consequently moves with it. This arrangement leads to a favorable flow pattern of the liquid which flows from the supply chamber into the pumping chamber, but it is within the scope of the invention to attach the flap to the pump housing, if necessary, and to make the arrangement for its movable part so that it is connected to the Displacement part interacts.

As with the other embodiments shown and described in which the inlet valve is a lip or flap valve, the inlet passage 17 -7 is opened to allow flow into the pumping chamber with very little pressure loss once the pressure is upstream from the valve only slightly exceeds the pressure on the downstream side. Similarly, the inlet passage is immediately closed when the pressure in the pumping chamber only slightly exceeds the pressure on the upstream side of the valve. The rapid opening and closing of the flap valves is due to the annular configuration and the consequently large surface area of the valve, via which the pressure acts. For the same reason, the outlet valve 20 -7 and corresponding to the outlet passage 18 -7 are closed immediately when the pressure in the outlet connection 14 -7 exceeds the pressure in the pumping chamber at the beginning of the suction stroke.

FIGS. 8A and 8B show a pump in which two displacement parts 25-8 A, 25-8 B are provided, which operate in Gegenpha se to reduce the volumes of different sections of the pump chamber at different times.

A displacement part 25-8 A is similar to the displacement part shown in FIGS . 4 to 6 and serves to reduce the volume of a central chamber portion 16-8 A of the second stage, which is similar to the pump chamber of FIGS . 4 to 6 and with communicates with a central outlet connection 14-8 .

The other displacement part 25-8 B is annular and concentric to the former central part. This annular outer part serves to reduce the volume of an annular pump chamber section 16-8 B with an external variable volume, which is concentric with the central chamber section 16-8 A of the second stage with variable volume.

On its radially inner side, the outer pump chamber section 16-8 B is connected to the central chamber section 16-8 A of the second stage by means of an annular passage 30-8 in which a one- way flap valve 31-8 , which is the flap valve of FIG. 3 and 5 is similar, provided in order to create an opening and to permit flow into the pump chamber section 16-8 a. This passage forms both an inlet passage of the central pump chamber section 16-8 A and an outlet passage of the outer pump chamber section 16-8 B.

On its radially outer side, the outer pump chamber section 16-8 B is connected to an annular feed chamber 15-8 , which is similar to the feed chamber of FIGS . 2 and 3, by means of an annular inlet passage 17- 8 with a one-way flap valve 23- 8 , which opens to allow the flow into the outer pump chamber part 16-8 B and which looks similar to the flap valve 23 -3 and 23-5 of FIGS . 3 and 5.

The two displacement parts 25-8 A and 25-8 B are essentially actuated in phase opposition by mechanisms which are similar to the mechanisms used for the actuation of the displacement part and pinch valves of FIG. 4. The maximum volumes of the pump chamber sections and the movements of the two displacement parts are selected so that the stroke volume of the outer pump chamber section 16-8 B is approximately twice that of the central pump chamber section 16-8 A.

Fig. 8A shows a phase of the operating cycle of the pump, in which the outer displacement part 25-8 B moves straight down and the outer pump chamber section 16-8 B is filled from the supply chamber 15-8 by means of the inlet passage 17-8 without that there is a noticeable pressure drop across the passageway as the second stage central displacer 25-8 A moves up to expel liquid from the second stage central chamber portion 16-8 A , with the flapper valve 31-8 driven by the pressure is kept in the closed state in the central chamber section.

In the phase shown in Fig. 8B, the situation is reversed. Accordingly, the outer displacement part 25-8 B is moving upward to discharge liquid from the outer pump chamber portion 16-8 B into the central chamber portion 16-8 A of the second stage through the passage 30-8 , while the central displacement part 25-8 A moves down and for the central chamber section 16-8 A provides the possibility to expand under the effect of the pressure of the liquid on its walls.

The volume of the liquid ejected from the outer pumping chamber portion during the upward movement of the outer displacement part is larger than the volume increase of the central chamber portion of the second stage. As a result, liquid is discharged through the outlet connection 14-8 also in this phase ( Fig. 8B) of the operating cycle of the pump. While the inflow to the pumping chamber takes place only in the phase in which the outer pumping chamber section is expanding, the emptying of the pump takes place essentially continuously, as with some pulsation.

The embodiment shown in Figs. 9A, 9B is similar in construction and operation to that shown in Figs. 8A and 8B except that the externally energized mechanism for effectively operating the inner displacer 25-9 A in the upward direction is replaced by an adjustable spring mechanism mus 26-9 A , which constantly pushes this displacement part upwards. During the upward stroke of the outer displacement part 25-9 A , the central displacement part 25-9 A of the second stage is moved down under the action of the fluid pressure in the central chamber portion 16-9 A of the second stage, whereby the spring mechanism 26-9 A is compressed as shown in Fig. 9A. During the downward movement of the outer displacement part 26-9 B , the energy stored in the spring mechanism moves the central displacement part upwards, as shown in FIG. 9A.

Figs. 10A, 10B are cross-sectional views corresponding to Fig. 8A, 8B and 9A, 9B, from a further exporting approximately the form of a two-stage pump of the invention, and FIG. 10C is a plan view of the chamber element of this further embodiment.

The pump shown in FIGS. 10A, 10B, 10C has two displacement parts 25-10 A and 25-10 B , which operate in the manner described with reference to FIGS. 9A, 9B. Accordingly, the displacer 25-10 B is associated with an externally energized drive mechanism for effectively or substantially safely actuating the same in the upward direction, while the displacer 25-10 A is associated with an adjustable spring mechanism 26-10 A , which it constantly upwards presses.

The two displacement parts 25-10 A and 25-10 B and the zugeordne th pump chamber sections 16-10 A and 16-10 B of the chamber element 12-10 are horizontally offset from one another, and the inlet valve 23-10 and the valve 31-10 between the pump chamber sections are flap valves similar to valves 23 -6 and 20-6 of FIGS. 6A, 6B, 6C. Further illustration of 10C, the inlet connection 13-10 and the outlet connection are shown in FIGS. 14-10 arranged side by side and substantially parallel.

Except for the different flow patterns resulting from the horizontally staggered arrangement of the chamber sections, the pump of FIGS. 10A, 10B, 10C operates in essentially the same manner as the pump of FIGS. 9A, 9B.

In the exemplary embodiments illustrated and described above, the pumping chamber 16 and the supply chamber 15 of the chamber member are circular or in the shape of a circular ring, and as can be easily understood, the mechanical pumping components are appropriately designed. This shape is usually preferred, both with regard to the fluid flow and the production, but it is within the scope of the invention that the pump can also have different or different design, such as. B. more or less oval or another elongated configuration. An elongated configuration may be particularly intended in the case of Figures 6A, 6B, 6C where the inlet and outlet are in alignment.

Furthermore, in the embodiments according to FIGS. 8A and 8B and FIGS . 9A, 9B, the central displacement parts 25-8 A , 25-9 A can be ring-shaped like the outer parts 25-8 B , 25-9 B. The open space within the central annular displacement part can then accommodate components of the pump drive mechanism, for example, or it can be used for other purposes. In such a case, if the drive mechanism for the two displacement parts 25-8 A and 25-8 B of FIGS . 8A, 8B is constructed such that the parts as a unit with a selected phase shift (e.g. reverse phase or bidirectional operation) or can be actuated individually (only one of the parts is actuated), there may be interesting possibilities for changing the pump properties with regard to the stroke volume and the output flow properties.

In some cases, such as B. when the pump is used as a blood pump, the displacement part can be connected in a suitable manner to the pump mechanism such that a resilient yielding of the displacement part relative to the pump mechanism is possible under the action of the pressure in the pump chamber, so that it there is a certain "sagging" of the displacement part during the pressure or ejection stroke. The movement of the displacer initially lost as a result of "slack" is "recovered" at the end of the pressure stroke and can be exploited to ensure that the liquid in the pumping chamber does not stagnate, ie under the valve flap 31-8 of Fig . 8A, 8B. Such an arrangement can also be used to suppress any pressure waves that attempt to develop at the end of the exhaust stroke.

A pump of the type of FIGS. 8A, 8B with two or more displacement parts and pump chamber sections, which are preferably annular, is also useful as a two-stage (multi-stage) compressor, particularly for compressing large amounts of air to a relatively low pressure. A feature of compressors constructed in this way is that only a single valve is required between the stages; each valve functions both as a radially outer or lower stage exhaust valve and as a radially inner or higher stage inlet valve. The other embodiments are also useful as compressors or air (or other gas) pumps, but are believed to work best as liquid pumps in practice.

As can be seen from the drawings, a feature of the pump according to the invention is that the pumped liquid has a favorable flow pattern because it can flow through the pump without having to apply any abrupt changes in direction to it. In this regard, the embodiments of FIGS. 1 to 6 and 8 to 10 are particularly advantageous, where the height of the pumping chamber is very small compared to the diameter and the liquid consequently flows essentially horizontally upwards to the outlet connection. The generally low or flat shape of the pumping chamber also allows a short stroke length, meaning that the stroke speed can become high. In conjunction with the large cross-sectional area that the inlet passage and outlet passage can have, this feature ensures a very low internal flow resistance of the pump.

In the embodiments of FIGS. 5 to 10, the use of single flap valves, which are attached to the lower wall of the chamber element 12 and can be moved upwards, in the direction of the fluid ejection movement of the displacement part into a position in sealing engagement with the upper wall, advantageous in that the fluid flow, which is generated by the displacement part, cleans the lower side of the flaps. This sweeping stream minimizes the risk of any particle of the fluid being pumped under or behind the valve flaps becoming stagnant or motionless. Accordingly, those embodiments are particularly suitable for pumping blood because they meet the very important requirement of blood pumps that they are free from motionless areas.

In the embodiments based on which the invention is exemplary was shown in connection with the drawings the displacement part and its drive mechanism under the Pump chamber arranged. This arrangement is in most cases preferred, especially when as illustrated Embodiments a separate, easily replaceable Kammerele made of plastic film or a thin layer or board Provides surfaces with which the currently pumped fluid comes into contact during its passage through the pump. In some cases, however, it may be preferred that the Displacement part forms or on the top wall of the pump chamber this acts and that the drive mechanism over the pump chamber is arranged. It is also conceivable that you have a common Has drive mechanism for two opposite pumps that are stacked on top of each other and work in opposite phase. It is also possible two drive devices for a single pump to have a drive mechanism for each side, who work in opposite directions.

The chamber 16-10 A and the resiliently biased displacement part 25-10 A embodiment of FIGS. 10A, 10B, 10C can be used in conjunction with the outlets of the single stage pumps of other configurations, such as a one-way valve and a device for equalizing the pulsating coming out Flow of the pump. In the case of blood pumps, such an arrangement creates a one-way outlet valve that is free of motionless areas and a compliant volume downstream of the valve.

Claims (28)

1. positive displacement pump with means for forming a feed chamber for receiving the fluid to be pumped, Einrichtun conditions for forming a pump chamber with variable volume, an inlet passage through which the fluid is passed from the feed chamber to the pump chamber, an outlet through which the fluid is withdrawn from the pumping chamber, a displacement part assigned to the pumping chamber, which is movable in opposite directions along a predetermined path in order to move through a variable displacement zone of the pumping chamber and alternately increase and decrease the volume of the chamber, drive means for moving of the displacer in at least one direction to reduce the volume of the pumping chamber and with inlet valve means for closing the inlet passage to block the backflow of fluid from the pumping chamber through the inlet passage, characterized in that the supply chamber ( 15 ) has generally been Lich the displacement zone of the pumping chamber ( 16 ) is arranged and essentially surrounds it and the inlet passage ( 17 ) extends essentially with the supply chamber ( 15 ) and extends to the pumping chamber ( 16 ) through an elongated, gap-like opening in an edge wall of the pumping chamber ( 16 ) opens, which is generally located to the side of the displacement zone, whereby fluid can enter the pump chamber ( 16 ) through the inlet passage ( 17 ) substantially without a loss of pressure. 2. Pump according to claim 1, characterized in that the pumping chamber ( 16 ) has a movable wall part which can be brought into engagement by the displacement part ( 25 ) during the exhaust stroke and can be disengaged during the suction stroke from the displacement part such that the stroke volume of the pump is formed by the supply of fluid from the supply chamber ( 15 ). 3. Pump according to claim 1 or 2, characterized in that the pumping chamber ( 16 ) is generally round. 4. Pump according to one of claims 1 to 3, characterized in that the dimensions of the pumping chamber ( 16 ) transverse to the direction of movement of the displacement part ( 25 ) are substantially larger than the dimensions in this direction of movement. 5. Pump according to one of claims 1 to 4, characterized in that the outlet ( 14 ) is arranged substantially in the middle of a stationary transverse wall of the pump chamber ( 16 ) opposite the displacement part ( 25 ). 6. Pump according to one of claims 1 to 5, characterized in that the supply chamber ( 13 ) is suitably designed such that it receives a continuous input stream of the fluid to be pumped and at least a portion of its content in the pump chamber ( 16 ) through allows the inlet passage ( 17 ) to flow out when the inlet valve device ( 23 ) is open, while a fluid reservoir is melted when the inlet valve device is closed. 7. Pump according to claim 2, characterized in that the movable wall part of the pump chamber ( 16 ) is formed from a flexible material and is displaced from the displacement part ( 25 ) during at least part of the discharge stroke of the pump. 8. Pump according to claim 7, characterized in that the movable wall part forms part of the lateral edge wall of the pump chamber ( 16 ) and a wall of the inlet passage ( 17 ) specifies and that the valve device is a Quetschven tilteil ( 23-1 , 23-2 ) having which is in engagement with the side edge wall part and movable such that it moves the edge wall part over the opening and thereby closes the inlet passage, and has drive means ( 24-1 , 24-2 ) for periodically moving the pinch valve part over the opening away. 9. Pump according to claim 3, characterized in that the inlet valve means comprises a substantially annular flap ( 23 ) made of flexible material which is fixed along one edge to a wall of the inlet passage ( 17 ), its other edge for movement in one open position is free to allow the input flow of the fluid into the pumping chamber ( 16 ) and in a closed position in engagement with the other wall of the inlet passage to stop the backflow of the fluid from the pumping chamber through the inlet passage. 10. Pump according to claim 3, characterized in that the inlet valve means ( 23-3 ) has a first annular flap made of flexible material, which is fixed along an edge to a wall of the inlet passage ( 17-3 ), and a second annular flap flexible material attached along one edge to the other wall of the inlet passage and the other edges of both flaps free to move to an open position to allow fluid to flow into the pumping chamber ( 16-3 ), and in a closed position in engagement with each other to stop the backflow of the fluid from the pumping chamber ( 16-3 ) through the inlet passage ( 17-3 ). 11. Pump according to one of claims 1 to 10, characterized in that the supply chamber ( 15 ) and the pumping chamber ( 16 ) are formed by first and second spaced wall parts, that at least one of the wall parts is made of a flexible material and a first part which is engageable with and disengageable from the displacement part ( 25 ) to change the volume of the pumping chamber ( 16 ) and a second part which forms a wall of the inlet passage ( 17 ). 12. Pump according to claim 11, characterized in that the Valve device has a pinch valve part, which engages with the second part of the one wall part, Has drive devices for the cyclical movement of the Pinch valve part only over a partial path across the inlet passage and has a flexible flap valve band, which is attached to the other wall of the inlet passage is and has a free edge that is movable for the Engagement with the second part of this one wall part below Response to the fluid pressure in the pumping chamber. 13. Pump according to claim 11, characterized in that the lateral edge wall of the pumping chamber ( 16 ) is generally round and the supply chamber ( 15 ) is generally annular and completely surrounds the pumping chamber. 14. Pump according to claim 11, characterized in that both the supply chamber ( 13-1 , 13-2 , 13-3 ) and the pump chamber ( 16-1 , 16-2 , 16-3 ) are annular and the outlet the pumping chamber is an annular opening ( 18-1 , 18-2 , 18-3 ) which is arranged on an inner boundary of the pumping chamber, generally transverse to the displacement zone. 15. Pump according to claim 14, characterized by a Auslaßven valve, which has a movable valve part ( 20-1 , 20-2 ), which engages with a third part of the flexible wall part, and drive devices ( 22 -1 , 22nd - 2 ) for reciprocating the valve member to displace the third portion of the flexible wall member into and out of engagement with an opposite edge of the outlet opening ( 18-1 , 18-2 ) to close and close it to open. 16. Pump according to claim 11, characterized in that the flexible wall part of the pump is the lower part and further means ( 10 , 27 ) are provided for supporting a fourth part of the flexible wall part, which forms the lower wall of the supply chamber ( 15 ). 17. Pump according to claim 16, characterized in that the device for supporting the fourth part of the flexible wall part has one or more rollers ( 27-1 , 27-4 ) and Einrich lines for rotating the rollers in an orbital path along the feed chamber ( 15th -1 , 15-4 ) to continuously stir or reciprocate the fluid in the feed chamber. 18. Pump according to claim 17, characterized in that the means for supporting the fourth part of the flexible wall part is a rigid stationary part ( 10 ). 19. Pump according to one of claims 1 to 18, characterized in that an outlet valve device ( 20 ) is provided in the outlet ( 14 ). 20. Pump according to one of claims 1 to 19, characterized by a chamber ( 16-8 A , 16-9 A , 16-10 A) of the second stage with variable volume in connection with the outlet ( 14- 8 , 14-9 , 14-10 ) from the pumping chamber ( 16-3 , 16-9 B , 16-10 B) so that it receives fluid which is drawn out of the pumping chamber by a one-way valve ( 31-8 , 31-9 , 31 -10 ) in the outlet from the pumping chamber to block the backflow of fluid from the second stage chamber into the pumping chamber, a drain passage leading from the second stage chamber, a second stage displacement part ( 25-8 A , 25 -9 A , 25-10 A) which is movable to alternately increase and decrease the volume of the second stage chamber and by drive means ( 26-8 A , 26-9 A , 26-10 A) to move the second stage displacer in at least one direction and reduce the volume of the second stage chamber. 21. Pump according to claim 20, characterized in that the Drive device has a source of external energy. 22. Pump according to claim 20, characterized in that the Drive device for the displacement part of the second Stage is a spring that stores energy when that Volume of the second stage chamber by flowing in the fluid from the pumping chamber is increased, and the stored released energy when there is no inflow from the Pump chamber into the chamber of the second stage. 23. Pump according to one of claims 20 to 22, characterized in that the stroke volume of the pumping chamber ( 16-8 B , 16-9 B , 16-10 B) is approximately twice the stroke volume of the chamber of the second stage ( 16-8 A , 16-9 A , 16-10 A) . 24. Pump according to one of claims 20 to 23, characterized in that the pump chamber ( 16-8 B , 16-9 B) is substantially annular and the chamber of the second stage ( 16-8 A , 16- 9 A) is substantially round and is generally disposed transversely to and surrounded by the pump chamber. 25. Pump according to one of claims 20 to 24, characterized in that the supply chamber ( 15-10 ) is substantially annular, the pump chamber ( 16-10 B) is substantially round, the outlet is a passage, which in general leads laterally out of the pump chamber, and the chamber of the second stage ( 16-10 A) is essentially round and is arranged laterally from and in the vicinity of the pump chamber. 26. Pump according to one of claims 1 to 25, characterized in that the volumetric capacity or the capacity of the feed chamber ( 15 ) is at least as large as that of the pump chamber ( 16 ). 27. Chamber element for a positive displacement pump, with first and second layers of flexible material which are sealingly connected at their peripheries and are permanently formed around a generally annular feed chamber ( 12 ), a generally round pump chamber ( 16 ) within the feed chamber and to specify an inlet passage ( 17 ) which forms an elongated, gap-like opening at the connection of the supply chamber with the pump chamber, an outlet opening ( 14 ) in a wall of the pump chamber and a suction opening ( 13 ) being provided in at least one wall of the supply chamber . 28. Chamber element according to claim 27, characterized in that the inlet valve is an annular flap ( 23 ) made of flexible material, which along one of its edges is connected to one of the layers near the inlet passage ( 17 ), its other edge being free, whereby the flap leaves the inlet passage open without fluid back pressure from the pump chamber ( 16 ) and bulges to close the inlet passage depending on the fluid back pressure from the pump chamber.