PUMP WITH COMPLEX FLUID PATH

Abstract

 The invention is about a pump (01) to pump a fluid. It comprises a casing with at least one hollow cylinder (02) with an upstream side and a downstream side. Inside the cylinder (02) a piston (04) is movably arranged. A driving unit (05) is in force connection with the piston (04) and able to move the piston (04) inside the cylinder (02). In contrast to regular piston-pumps, the piston has at least one fluid path (10) from the upstream side to the downstream side with a design so that a fluid is able to flow with reduced resistance from the upstream side to the downstream side and a fluid flow from the downstream side to the upstream side is hindered by an increased resistance.

Description

[0001] The invention is about a pump to pump fluids by oscillating piston within a cylinder.

[0002] Pumps are known from the state of the art in many different embodiments with different methods of function. Here, pumps for liquid fluids are considered. Regular it is necessary to have a moving part. A common solution is a so-called piston pump, where within a cylinder a piston is oscillating. This leads to an increase and a decrease of the volume on one side of the piston, which as result leads to a flow of the fluid into the cylinder and back out of the cylinder. To enable the pumping of the fluid two valves are necessary. The first valve enables the flow of the fluid from a source into the cylinder and the second valve enables the flow of the fluid out of the cylinder to the destination.

[0003] An obvious disadvantage of those pumps is the movement of the valve with each movement of the piston and a wear of them. This limits the lifetime of the pump and the reliability.

[0004] Task for the current invention is the increase of the lifetime and reliability of the piston pump.

[0005] The task is solved by a pump according claim 1. Advantageous embodiments are subject of the sub-claims.

[0006] The generic pump can pump a fluid of different kind. In principle it is also possible to pump a gaseous fluid. But primary the pump is designed to pump a liquid fluid. The pump comprises a casing with at least one hollow cylinder. The further design of the casing is currently not of interest. Thereby, the cylinder defines a cylinder axis. With the intended flow of the fluid through the cylinder an upstream side and opposite a downstream side is defined. Within the cylinder a piston is arranged. The piston could be moved inside the cylinder over a limited distance along the cylinder axis in both directions.

[0007] A movement of the piston is necessary to enable the pumping of a fluid by the pump. Therefore, a driving unit is necessary, which is in connection with the piston. It is not mandatory, that the driving unit is in a direct contact with the piston. Rather it is sufficient, that the driving unit can apply a force on the piston, so that the piston moves inside the cylinder against a pressure gradient at both sides of the piston.

[0008] To extend the lifetime and to enhance the reliability inventively a fluid path is added into the piston which enables a fluid flow through the piston from the upstream side to the downstream side.

[0009] At first instance this seems to make no sense. At first glance, a fluid path inside the piston will lead to a fluid flow through the piston opposite to the movement of the piston inside the cylinder. Further, an arrangement of the usually used valves for the inlet flow into the cylinder and the outlet flow out of the cylinder will increase the resistance and as result the fluid flow through the fluid path inside the piston opposite to the movement of the piston will be increased.

[0010] To enable the pumping of the fluid it is therefore necessary to design the fluid path in that the resistance against a fluid flow through the piston is reduced when the fluid flows from the upstream side to the downstream side. Opposite to this it is further necessary that the resistance against a fluid flow from the downstream side to the upstream side is increased.

[0011] Here the key benefit is the omission (except the piston inside the cylinder) of the otherwise at previous designs necessary moveable parts. The regular necessary valves could be avoided (even it is possible to arrange them additionally).

[0012] It must be noted, that in principle a flow of fluid is also possible from the downstream side to the upstream side. But due to the different resistance of the fluid flow from the upstream side to the downstream side opposite to the fluid flow from the downstream side to the upstream side with each movement of the piston a pumping effect is achieved.

[0013] To enable a connection to other fluid lines advantageously the volume of the hollow cylinder is closed by the casing on both ends of the cylinder. This could be done by a single casing or also by an assembly of different parts. Irrespective of the concrete solution an input connector should be arranged at the upstream side of the cylinder and an output connector should be arranged at the downstream side of the cylinder, so that a source of fluid could be connected to the input connector at the upstream side and a destination for the fluid could be connected to the output connector at the downstream side.

[0014] It could be foreseen that the driving unit penetrates the casing at least at one side of the cylinder. If so, the driving unit is preferably arranged at the upstream side of the cylinder.

[0015] As further solution it is possible to design the pump with the piston and the driving unit similar to a linear actuator, wherein the piston is driven by a magnetic force.

[0016] To increase the possible pressure difference of the pump it is possible to arrange two or even more cylinders inside the pump each cylinder equipped with at least one piston. In this case each of the piston must have a fluid path with the relevant feature of the different resistance dependent on the direction of flow. Next, it is obvious, that the fluid path needs to be arranged in that the fluid flows in series from the respective upstream side to the respective downstream side through the pistons to increase the possible pressure of the pump. It is possible to arrange the cylinders with a common cylinder axis preferably with a common casing. But it is also possible to arrange the cylinders beside each other also preferably with a common casing.

[0017] To achieve the different resistance for the fluid flow through the pistons different solutions are possible.

[0018] An advanced embodiment comprises a fluid path with at least four different sections with a specific arrangement. Each of the section should comprise a smooth course. This means that the resistance of a section should not be significantly changed at a certain position and there should be no kink and no abrupt change of the cross-section within the respective section.

[0019] This solution is described in detail in the following as advanced solution, which is not necessary the only possible implementation to achieve the desired difference of the resistance through the fluid path.

[0020] At the upstream side an upstream section with a smooth upstream course is arranged. The upstream section must not necessary be arranged directly at the upstream end of the piston at the upstream side. Instead the upstream section could also be arranged inside the piston wherein the fluid path comprises at least one further section upstream of the upstream section.

[0021] Next, a downstream section with a smooth downstream course is necessary. Following the flow of fluid along the fluid path the downstream section is arranged downstream of the upstream section. Here, it is also not necessary that the downstream section is ending at downstream end of the piston at the downstream side.

[0022] Further, a joining section with a smooth joining course is necessary. This connects the upstream section with the downstream section. Thereby, it is necessary that the joining course is a smooth continuation of the upstream course.

[0023] Even this already enables a flow of the fluid from the upstream section to the downstream section, preferably a turnaround section with a smooth turnaround course is also added, whereby this also connects the upstream section with the downstream section in principle parallel to the joining section. To achieve the difference of the resistance through the fluid path it is necessary to design the turnaround section in that the turnaround course is a smooth continuation of the downstream course.

[0024] The upstream section as smooth continuation of the joining section and the connection with the turnaround section leads to an upstream junction of the upstream course with the joining course and with the turnaround course.

[0025] Analogous, the downstream section as smooth continuation of the turnaround section and the connection with the joining section leads to a downstream junction of the downstream course with the joining course and with the turnaround course.

[0026] Due to the connection of three different sections at a junction an obviation angle exists between two different courses of the respective sections - except those in smooth continuation with 180 deg. Here, an upstream obviation angle at the upstream junction is given as angle between the upstream course and turnaround course. Analog, a downstream obviation angle at the downstream junction is given between the joining course and the turnaround course.

[0027] It must be noted, that in case of a curved course the angle is determined by a tangent of the curved course at the respective junction.

[0028] The different resistance of the flow path with a lower resistance in case of a flow from the upstream side to the downstream side and an increased resistance for a flow from the downstream side to the upstream side could be achieved advantageously if the upstream obviation angle and also the downstream obviation angle is at least 15 deg and at most 75 deg.

[0029] The difference of the resistance for the flow in the two directions could be increased by adding a further input section with a smooth input course and a rebound section with a smooth rebound course. The input section could - but not obligatory - be arranged with the start at an input opening of the flow path at the piston. Here, the rebound course should be a smooth continuation of the upstream course. The connection of the input course to the rebound course and to the upstream course leads to a rebound junction. Again, a rebound obviation angle at the rebound junction between the input course and the rebound course should preferably at least 15 deg and at most 75 deg.

[0030] Downstream of the downstream section advantageously the fluid path comprises further a second upstream section with a smooth second upstream course and a second rebound section with a smooth second rebound course. Analog as before, the second rebound section should be a smooth continuation of the second upstream course. Thereby, the connection of the downstream course with the second rebound course and with the second upstream course leads to a second rebound junction. Again, a second rebound obviation angle at the second rebound junction between the downstream course and the second rebound course should be at least 15 deg and at most 75 deg.

[0031] A further improvement of the effect of different resistance of the flow path could be advantageously achieved with a repetition of the use of the joining section and the turnaround section. Therefore, the advantage flow path comprises a second upstream section with a smooth second upstream course and a second joining section with a smooth second joining course and a second turnaround section with a smooth turnaround course. Here, the second upstream section needs to be connected directly or indirectly with the downstream section. It is also possible - depending on the arrangement of further sections if applicable - to design the downstream section and the second upstream section with a continuous smooth course (i.e., the downstream section and the second upstream section appears as only one section).

[0032] Analog to the smooth connection of the joining course with the upstream course, the second joining course should be a smooth continuation of the second upstream course. This leads to a second upstream junction between the second upstream course and the second joining course and the second turnaround course. A second upstream obviation angle is given at the second upstream junction between the second upstream course and the second turnaround course, which should be at least 15 deg and at most 75 deg.

[0033] As a further improvement the downstream end of the second joining course is in connection with the downstream end of the second turnaround course at a second downstream junction. Here, a second downstream obviation angle is given at the second downstream junction between the second joining course and the second turnaround course. Similar as before, advantageously the downstream obviation angle is at least 15 deg and at most 75 deg.

[0034] Dependent on the size of the piston and the design of the fluid path, a first advantage embodiment comprises an output opening of the fluid path arranged at the downstream end of the piston at the second downstream junction (the second downstream junction is at the output opening). As result with this advantage, a fluid flow could enter into both the joining section and the turnaround section at the output opening (if a flow of fluid occurs from the downstream side to the upstream side).

[0035] To complete the analogue design with the second joining section and the second turnaround section, a second in particular advantage embodiment of the fluid path it comprises further a second downstream section with a smooth second downstream course. In this case the second downstream course should be a smooth continuation of the second turnaround course. This leads to the connection of the second joining section and the second turnaround section and the second downstream section at the second downstream junction.

[0036] Thereby, preferably an output opening of the fluid path is arranged at the downstream end of the second downstream course.

[0037] Even it has been found as beneficial to use an obviation angle between 15 deg and 75 deg at the upstream junction and at the downstream junction or if applicable at the further junctions as described before, a further advantage could be achieved if at least one of the obviation angles is limited further.

[0038] If a flow from the downstream side to the upstream side occurs, the fluid will preferably flow straight on at the respective junction and is hindered somehow to flow into the further section which branches off at the junction to the upstream side along the fluid path. Especially at the downstream junction, it is advantage if the upstream obviation angle is at least 30 deg. The same applies if applicable to the second downstream obviation angle. To increase the effect, the upstream obviation angle respectively second downstream obviation angle is preferably at least 40 deg.

[0039] A further target of the advantage design of the fluid path is a possible turnaround of a fluid flow from the downstream side to the upstream side due to the shape of the turnaround section respectively second turnaround section. If a flow from the downstream side to the upstream side is considered, a flow though the downstream section will preferably continue at the downstream junction into the turnaround section. At the end of the turnaround section at the upstream junction the flow comprises a direction of flow back from the upstream side to the downstream side against a fluid flow inside the joining section from the downstream junction to the upstream junction. Therefore, it is advantage to limit the upstream obviation angle to 60 deg. The same applies if applicable to the second upstream obviation angle. This effect of intended opposite flow at the upstream junction respective second upstream junction is enhanced if the upstream obviation angle is at most 50 deg.

[0040] If a rebound junction is given it is also advantageous to have a rebound obviation angle of at least 30 deg. In principle it is preferred to set every obviation angle within a range between 30 deg and 60 deg. This could further be limited to a range of the obviation angle between 40 deg and 50 deg.

[0041] In the following figures two different examples for an inventive pump are sketched.

Fig. 1

a first example for an inventive pump is shown;

Fig. 2

comprises the courses of the fluid path of the solution shown in Fig. 1;

Fig. 3

shows an exemplary model in a 3D view to realize the solution of Fig. 1;

Fig. 4

a second example for an inventive pump is shown;

Fig. 5

comprises the courses of the fluid path of the solution shown in Fig. 4.

[0042] In Figure 1 a sketch for a first exemplary embodiment of an inventive pump 01 is shown. It 01 comprises a casing with a hollow cylinder 02, which defines a cylinder axis 03. Inside the hollow cylinder 02 a piston 04 is arranged. This could be moved inside the hollow cylinder 02 along the cylinder axis 03 in the opposite directions. To enable a movement of the piston a driving unit 05 is necessary. Here only part of the driving unit 05 with a piston rod is shown. With respect to the invention the execution of the driving unit 05 is not relevant, except it 05 could act a force on the piston 04. The hollow cylinder 02 is closed on both sides by the casing, wherein at an upstream end (in the sketch at the top side) of the cylinder 02 an input connector 06 is arranged. In operation intentionally the fluid flows through the input connector 06 into the hollow cylinder 02.

[0043] The forgoing description of a pump with a cylinder and a piston movable arranged inside the cylinder applies equal to a regular common piston pump.

[0044] The example of an inventive pump 01 comprises a piston 04 with a fluid path 10, which 10 extends from the upstream end of the piston 04 to the downstream end. This enables a fluid flow from the upstream side to the downstream side and reverse. To pump the fluid by the pump 01 it is not intended, that the fluid is pumped out of cylinder 02 at the upstream side of the piston 04 by a movement of the piston to the upstream side. Instead, intentionally with a movement of the piston 04 to the upstream side the fluid will flow through the fluid path 10 to the downstream side of the piston 04. At the downstream side of the piston the hollow cylinder 02 is also closed by the casing (except there is the rod of the driving unit penetrating the casing). Analog to the upstream side, at the downstream side an output connector 07 is arranged. If the piston 04 is now moved from the upstream side to the downstream side it 04 will pump the fluid, which is located in the cylinder 02 at downstream side relative to the piston 04, through the output connector 07.

[0045] To enable a sufficient fluid flow from the upstream side through the fluid path 10 to the downstream side of the piston 04 the fluid path 10 comprises a reduced resistance for such a flow direction.

[0046] Opposite to this, a fluid flow from the downstream side to the upstream side of the piston 04 through the fluid path 10 should be prevented. Therefore, the design of the exemplary fluid flow 10 leads to an increased resistance against a fluid flow from downstream to upstream side.

[0047] At this example the piston 04 is designed with the fluid path 10 as revolving part. This leads due to the revolving fluid path 10 to in principle separate inner subparts inside the fluid path 10. Therefore, ribs 08 are provided to connect the inner subparts to the outer subpart of the piston 04.

[0048] This revolving design could be seen best with the iso view of an example design for the piston 04 in Figure 3. Next, with this design it is possible to split the piston 04 into two stacked half pistons 09. It is obvious, that it is possible to arrange further half pistons 09 on top each other to increase the length of the fluid path 10 and as result the difference for the resistance for a flow from upstream to downstream and vice versa.

[0049] The fluid path 10 itself with the exemplary design is shown in Figure 2 on the basis of the courses of the different sections of the fluid path 10.

[0050] It should be noted that a course represents the centre curve of the respective section of the fluid path 10.

[0051] The fluid path 10 starts at the upstream side with the input opening 22. From there the input course 11 leads to the rebound junction 23. An upstream course 13 is connected with a smooth connection with a rebound course 12 at the rebound junction 23. As result the input course 11 branches off at the rebound junction 23 with a resulting rebound obviation angle between the rebound course 12 and the input course 11.

[0052] The upstream course 13 leads at the other side to an upstream junction 24 and continues smoothly with a joining course 14. Downstream of the joining course 14 a downstream junction 25 is arranged. Fluidly parallel to the joining course 14 a turnaround course 15 is arranged. With the smooth connection of the joining course 14 with the upstream course 13 an upstream obviation angle exists between the turnaround course 15 and the upstream course 13. Downstream of the downstream junction 25 a downstream course 16 is arranged. This 16 is analogy designed with a smooth continuation of the turnaround course 15. As result a downstream obviation angle exists between the turnaround course 15 and the joining course 14 at the downstream junction 25.

[0053] The design of the fluid path 10 from the rebound junction 23 to the downstream junction 25 is arranged twice, wherein a second rebound junction 26 connects the downstream course 16 with a second rebound course 17 and a second upstream course 18. Regarding the second rebound obviation angle the same applies as for the rebound obviation angle. Downstream of the second upstream course 18 again fluidly parallel a second joining course 19 and a second turnaround course 20 are arranged with a second upstream junction 27 and a second downstream junction 28.

[0054] With this example it is intended, that the second downstream junction 28 represents an output opening 29 at the downstream end of the piston 04.

[0055] Due to the arrangement of the courses with several times that - with respect to a fluid flow from the downstream side to the upstream side - the follow course branches off from a smooth continuation into the wrong direction the resistance against a fluid flow in such a direction is increased against a fluid flow from the upstream side to the downstream side. Here the fluid must follow several times a kink, but the fluid is not guided into the wrong direction by the branching courses, i.a. the turnaround sections 15, 20.

[0056] In Figure 4 a further example for an inventive pump 51 is shown. Here, also a piston 54 is arranged inside a hollow cylinder 52 with a fluid path 60 penetrating the piston 04 from the upstream side to the downstream side. Equal as used in the foregoing example at the upstream side an input connector 56 and at the downstream side an output connector 57 are arranged. Different to the foregoing solution in this case a driving unit 55 without a direct connection to the piston 54 is used. Without showing any details regarding the driving unit 55 it could design similar to a linear drive.

[0057] Next difference to the foregoing solution of figure 1, this embodiment comprises a fluid path 60 with two separated subparts, wherein the fluid path 60 extends not with a revolving shape but in a direction square to the cylinder axis 53. Obviously, the width (into the drawing plane) of the fluid path 60 could be much larger if closer to the cylinder axis 53 than at side close to the outer side of the piston 54 (both sides at the sketch). To compensate the difference in the width, the thickness (left-right in the figure) of the fluid path 10 could be chosen opposite much lower at the area close to the cylinder axis 53 and much thicker at the area close to the side of the outer side of the piston 54.

[0058] Irrespectively, the fluid path 60 again comprises several sections as it is shown in Figure 5. At the upstream end an input opening 72 is the beginning of the fluid path 60. Here, an upstream course 63 starts and ends at the upstream junction 74. Analog the previous embodiment from the upstream junction 74 fluidly parallel to each other a joining course 64 and a turnaround course 65 extends up to a downstream junction 75. Equal as at the previous solution the joining course 64 is a smooth continuation of the upstream course 65. Again, an upstream obviation angle is given between the upstream course 63 and the turnaround course 65 at the upstream junction 74. The turnaround course 65 continues at the downstream junction 75 smoothly with a downstream course 66. This leads again to a downstream obviation angle between the turnaround course 65 and the joining course 64.

[0059] The arrangement with the upstream course 63, joining course 64, turnaround course 65 and the downstream course 66 is repeated with a different shape. As result the example of a fluid path 60 further comprises a second upstream course 68 and a second joining course 69 and a second turnaround course 70 and a second downstream course 71. Here the solution comprises further analogy the second upstream junction 77 with a second upstream obviation angle between the second upstream course 68 and the second turnaround course 70 and further the second downstream junction 78 with the second downstream obviation angle between the second joining course 69 and the second turnaround course 70.

[0060] Different to previous embodiment of figure 1 respectively figure 2 the solution of figure 4 respectively figure 5 comprises the second downstream section / course 71, which leads to an output opening 79 and the downstream end of the second downstream section 71.

[0061] It must be noted, that the advantage repetition of the arrangement with the upstream course, the joining course and the turnaround course could be realized with the connection of the first arrangement upstream and the second arrangement downstream of the first arrangement in different ways.

[0062] Here, in figure 1 and 2 a first embodiment with a kink between the downstream course 16 and the second upstream course 18 is presented. Against this in figure 4 and 5 a second embodiment presents a solution, wherein the downstream course 66 and the second upstream course 68 could not be divided into two distinguish parts. Instead, the part of the fluid path between the downstream junction 75 and the second upstream junction 77 appears as one smooth section.

[0063] The relevant advantage feature of the exemplary embodiments is the arrangement of the sections, so that the further upstream section from the output opening to the input opening branches off from another smooth forward course.

Claims

1. Pump (01, 51) to pump a, in particular liquid, fluid comprising a casing with at least one hollow cylinder (02, 52), which (02, 52) is defining a cylinder axis (03, 53) and has an upstream side and a downstream side, and at least one piston (04, 54), which (04, 54) is movably arranged inside the cylinder (02, 52), and a driving unit (05, 55), which (05, 55) is in force connection with the piston (04, 54) and able to move the piston (04, 54) inside the cylinder (02, 52),
characterized in that
the piston has at least one fluid path (10, 60) from the upstream side to the downstream side with a design so that a fluid is able to flow with reduced resistance from the upstream side to the downstream side and a fluid flow from the downstream side to the upstream side is hindered by an increased resistance.

2. Pump (01) according to claim 1,
wherein the volume of the cylinder (02, 52) is closed by the casing and if applicable by the driving unit (05) except an input connector (06, 56) at the upstream side of the cylinder (02, 52) and except an output connector (07, 57) at the downstream side of the cylinder (02, 52).

3. Pump according to claim 1 or 2,
comprising at least two separate or combined cylinders each with at least one piston having a fluid path, wherein the fluid path of the pistons is arranged in that the fluid flows in serial through the pistons.

4. Pump (01) according to one of the claims 1 to 3,
wherein the fluid path (10, 60) comprises

- an upstream section with a smooth upstream course (13, 63), and

- a downstream section with a smooth downstream course (16, 66), and

- a joining section with a smooth joining course (14, 64) as smooth continuation of the upstream course (13, 63), and

- a turnaround section with a smooth turnaround course (15, 65) as a smooth continuation of the downstream course (16, 66), and

- an upstream junction (24, 74) of the upstream course (13, 63) and the joining course (14, 64) and the turnaround course (15, 65), and

- a downstream junction (25, 75) of the downstream course (16, 66) and the joining course (14, 64) and the turnaround course (15, 65),

wherein an upstream obviation angle at the upstream junction (24, 74) between the upstream course (13, 63) and turnaround course (15, 65) is at least 15 deg and at most 75 deg and
wherein a downstream obviation angle at the downstream junction (25, 75) between the joining course (14, 64) and the turnaround course (15, 65) is at least 15 deg and at most 75 deg.

5. Pump (01) according to claim 4,
wherein the fluid path (10) comprises further

- an input section with a smooth input course (11), and

- a rebound section with a smooth rebound course (12) as a smooth continuation of the upstream course (13), and

- a rebound junction (23) of the input course (11) and the rebound course (12) and the upstream course (13), wherein a rebound obviation angle at the rebound junction (23) between the input course (11) and the rebound course (12) is at least 15 deg and at most 75 deg.

6. Pump (01) according to claim 4 or 5,
wherein the fluid path comprises further

- a second upstream section with a smooth second upstream course (18), and

- a second rebound section with a smooth second rebound course (17) as a smooth continuation of the second upstream course (18), and

- a second rebound junction (26) of the downstream course (16) and the second rebound course (17) and the second upstream course (18),

wherein a second rebound obviation angle at the second rebound junction (26) between the downstream course (16) and the second rebound course (17) is at least 15 deg and at most 75 deg.

7. Pump (01, 51) according to one of the claims 4 to 6, wherein the fluid path (10, 60) comprises further

- a second upstream section with a smooth second upstream course (18, 68) in connection with the downstream course (16, 66), and

- a second joining section with a smooth second joining course (19, 69) as a smooth continuation of the second upstream course (18, 68), and

- a second turnaround section with a smooth turnaround course (20, 70), and

- a second upstream junction (17, 77) of the second upstream course (18, 68) and the second joining course (19, 69) and the second turnaround course (20, 70), wherein a second upstream obviation angle at the second upstream junction (17, 77) between the second upstream course (18, 68) and the second turnaround course (20, 70) is at least 15 deg and at most 75 deg.

8. Pump (01, 51) according to claim 7,
wherein the fluid path (10, 60) comprises further

- a second downstream junction (18, 78) at the downstream end of the second joining course (19, 69) and the second turnaround course (20, 70),

wherein a second downstream obviation angle at the second downstream junction (28, 78) between the second joining course (19, 69) and the second turnaround course (20, 70) is at least 15 deg and at most 75 deg.

9. Pump (01) according to claim 8,
wherein the fluid path (10) comprises further

- an output opening (29) arranged at the second downstream junction (28), so that a fluid flow could enter into both the joining section (19) and the turnaround section (20).

10. Pump (51) according to claim 8,
wherein the fluid path (60) comprises further

- a second downstream section with a smooth second downstream course (71) as a smooth continuation of the second turnaround course (70)

11. Pump (51) according to claim 10,
wherein the fluid path (60) comprises further

- an output opening (79) arranged at the downstream end of the second downstream course (71).

12. Pump according to one of the claims 4 to 11,
wherein the downstream obviation angle, and in particular the second downstream obviation angle, is at least 30 deg, in particular at least 40 deg.

13. Pump according to one of the claims 4 to 12,
wherein the upstream obviation angle, and in particular the second upstream obviation angle, is at most 60 deg, in particular at most 50 deg.

Drawing