Gas recirculation device and system having such a device

Abstract

The invention relates to a recirculation device for a gas of a process device, said recirculation device comprising a recirculation pump, wherein the recirculation pump is a side channel pump.

Claims

1. A recirculation device for a gas of a process device, said recirculation device comprising: a recirculation pump, wherein the recirculation pump is a side channel pump which includes a rotor having a plurality of rotor blades; wherein an intermediate space between two rotor blades adjacent in a direction of movement has a pointed roof-shaped structure defining a ridge edge, wherein each ridge edge extends from a respective blade tip to a base of an adjacent blade, such that the adjacent rotor blades are not connected with each other via the roof-shaped structure.

2. The recirculation device in accordance with claim 1, wherein the gas includes at least one of hydrogen, a temperature control medium, and CO.sub.2.

3. The recirculation device in accordance with claim 1, wherein the rotor blades are each at least one of straight, oblique, arrow-shaped, curved, divided, undivided, or inclined to the front or to the rear in the direction of movement.

4. The recirculation device in accordance with claim 1, wherein at least one side channel of the side channel pump has a circular, oval, elliptical, rectangular, or egg-shaped cross-sectional geometry.

5. The recirculation device in accordance with claim 1, wherein at least one side channel of the side channel pump tapers in its cross-section in a flow direction.

6. The recirculation device in accordance with claim 1, wherein the side channel pump has a single-stage or multi-stage design.

7. The recirculation device in accordance with claim 1, wherein the side channel pump has a sealed region; and wherein parts of the pump that are movable to produce the pumping effect are arranged within the sealed region.

8. The recirculation device in accordance with claim 1, wherein the rotational speed of the side channel pump is controllable via a frequency converter.

9. The recirculation device in accordance with claim 1, wherein the rotor of the side channel pump is supported by at least one grease-lubricated bearing.

10. A system comprising a process device having a space and/or a line for receiving a gas; and a recirculation device by which the gas can be removed from the process device and can be returned into the process device, said recirculation device comprising a recirculation pump, wherein the recirculation pump is a side channel pump which includes a rotor having a plurality of rotor blades; wherein an intermediate space between two rotor blades adjacent in a direction of movement has a pointed roof-shaped structure defining a ridge edge, wherein each ridge edge extends from a respective blade tip to a base of an adjacent blade, such that the adjacent rotor blades are not connected with each other via the roof-shaped structure.

11. The system in accordance with claim 10, wherein a closed gas circuit is provided.

12. The system in accordance with claim 10, wherein the process device comprises a laser.

13. The system in accordance with claim 10, wherein the process device comprises a temperature control apparatus.

14. The system in accordance with claim 10, wherein the process device comprises a fuel cell.

15. The system in accordance with claim 10, wherein the process device comprises a combustion device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained only by way of example in the following with reference to the schematic drawing.

(2) FIG. 1 shows a side channel pump in a perspective view;

(3) FIG. 2 shows the side channel pump of FIG. 1 in a sectional view;

(4) FIG. 3 shows a further side channel pump in a perspective view;

(5) FIG. 4 shows the side channel pump of FIG. 3 in a sectional view;

(6) FIG. 5 shows a third embodiment of a side channel pump in a perspective sectional view;

(7) FIG. 6 shows a part region of the side channel pump enlarged with respect to FIG. 5 in a sectional view;

(8) FIGS. 7 to 12 show different embodiments of rotors for a side channel pump; and

(9) FIGS. 13 to 15 show different systems with a process device and a recirculation device.

DETAILED DESCRIPTION OF THE INVENTION

(10) FIG. 1 shows a side channel pump 20 for use as a recirculation pump in a recirculation device in accordance with the invention for a gas of a process device. The pump 20 is shown in isolation in the top region so that a rotor 22 is visible that rotates to provide a pumping effect. It can be seen from FIG. 2 that the pump 20 has only one rotor 22, i.e. it has a single-stage design. The rotor 22 rotates with a plurality of rotor blades 24 distributed over its periphery in a side channel 26. The side channel 26 is an annular channel that is slightly larger in its cross-section than a respective rotor blade. In the present embodiment, the side channel 26 is substantially rectangular in cross-section, but is designed with rounded corners.

(11) The rotor 22 is arranged on a shaft 28 of the side channel pump 20. The shaft 28 and thus the rotor 22 are rotationally driven via an electric motor that comprises a stator 30 and a rotor 32. The stator 30 has energized windings, whereas the rotor 32 in this embodiment has a plurality of permanent magnets. The rotor 32 is fixedly connected to the shaft 28. The shaft 28 and thus the rotor 22 are therefore directly driven by the electric motor 30, 32.

(12) In this embodiment, the rotor 22 is designed with curved rotor blades 24 slightly obliquely inclined to the rear in the direction of movement and with a flat intermediate space between the rotor blades 24.

(13) FIGS. 3 and 4 show a two-stage side channel pump 20 that has two rotors 22.1 and 22.2 that are supported on a common shaft 28. The rotors 22.1 and 22.2 rotate in respective side channels 26.1 and 26.2 that here likewise have a substantially rectangular cross-section. A connection 34 of the side channels 26.1 and 26.2 can be seen in the top region of FIG. 4.

(14) The rotors 22.1 and 22.2 each have arrow-shaped blades 24 that are slightly obliquely inclined to the rear in the direction of movement. In the intermediate spaces of the blades 24, the rotor 22 is flat in each case. The direction of movement here preferably extends in the direction of the tips of the respective arrow-shaped blades 24. In general, however, a reverse operation is also possible, for example.

(15) The shaft 28 that carries the rotors 22 is driven by an electric motor. The electric motor has a stator 30 that has windings and a permanent magnet rotor 32 that is seated on the shaft 28. The rotor 32 and the shaft 28 are arranged within a pipe 36 that is part of a hermetic seal of the pump 20. Such a pipe 36 is also designated as a can because it extends through the gap between the rotor 32 and the stator 30 of the electric motor. Accordingly, the electric motor is designated as a canned motor. The can 36 can, for example, be manufactured from a glass fiber composite. The rotor 32 and the shaft 28 are located behind the hermetic seal from the viewpoint of the environment and in a region that is substantially passed through by the gas to be conveyed by the pump and that has a corresponding pressure level.

(16) Two bearings 38 are furthermore located behind the seal or in the region of the gas to be conveyed. They are preferably grease-lubricated and/or permanently lubricated.

(17) The functional elements arranged in the gas region or behind the seal are therefore substantially independently functional. They in particular do not have to be supplied in a wired manner, for instance, with power or an operating medium. The rotors 22 moreover run contactlessly in the housing gaps 40 provided for them. The functional parts in the gas region are thus extremely low-wear and low-maintenance. The hermetic seal of the pump 20 therefore only has to be broken extremely rarely during a dismantling in order to service the pump.

(18) A third embodiment of a side channel pump 20 is shown in FIG. 5. The side channel pump 20 has five stages, that is, five rotors 22 are provided that rotate in respective side channels 26. The rotors 22 are again arranged on a common shaft 28. A region A of the side channel pump 20 indicated in FIG. 5 is shown enlarged and rotated by 90 degrees in FIG. 6.

(19) It can be seen from FIG. 6 that the side channels 26.1 and 26.2 of the first two pump stages are substantially rectangular, whereas the side channels 26.3, 26.4 and 26.5 of the remaining pump stages have a substantially oval or egg-shaped cross-section. As can in particular be seen from FIG. 5, the rotors 22.1 and 22.2 each have curved rotor blades. In contrast, the rotors 22.3, 22.4 and 22.5 are arrow-shaped. The rotors 22.3, 22.4 and 22.5 furthermore have a pointed roof-shaped structure 42 in the respective intermediate spaces between adjacent rotor blades 24 that supports the pumping effect by promoting a vortex formation of the gas flow in the side channel 26.

(20) Different advantageous embodiments of rotors 22 are shown in FIGS. 7 to 12. The rotor 22 of FIG. 7 has curved rotor blades 24 having flat intermediate spaces.

(21) The rotor 22 of FIG. 8 has planar rotor blades 24 that extend radially. Roof-like structures 42 are respectively provided between the rotor blades 24, with a respective ridge edge 44 extending in parallel with the direction of movement of the rotor blades 24. The ridge edge 44 connects radially outer ends of the blades 24 in so doing. They are thus connected rotor blades 24. The surfaces 46 converging toward the ridge edge 44 are concave.

(22) The rotors 22 of FIGS. 9 to 11 are all arrow-shaped and substantially differ in size, the number of blades, or the relative blade spacing. They additionally have a roof-like structure 42 having a respective ridge edge 44 in the intermediate blade spaces. In this respect, the ridge edges 44 of the rotors 22 of FIGS. 9 and 10 are curved themselves, whereas the ridge edge 44 in FIG. 11 is substantially straight. All the ridge edges 44 of FIGS. 9 to 11 extend from a respective blade tip to a base of an adjacent blade. The rotor blades 24 are thus not connected.

(23) The blades 24 of the rotor 22 of the embodiment shown in FIG. 12 are finally curved, wherein they in particular differ from the embodiment of FIG. 7 with respect to number and size.

(24) A system having a process device 50 and a recirculation device 52 is shown in FIG. 13, wherein the recirculation system 52 has a recirculation pump configured as a side channel pump 20. The process device 50 has an inlet 54 and an outlet 56. The inlet 54 is connected to the recirculation device 52 such that a returned gas is returned into the inlet 54. In addition, a further mass flow is supplied to the inlet 54 via a further line. Similarly, the outlet 56 is connected both to the recirculation device 52 or the side channel pump 20 and to a further line that takes up a partial mass flow of the outlet 56. In the system of FIG. 13, a portion of a mass flow that passes through the process device is therefore recirculated. The process device 50 can, for example, be a fuel cell. In this case, the mass flow can include hydrogen, for example. Excess hydrogen that has not been consumed by the fuel cell is returned to the inlet 54 via the recirculation device 52 in order to be consumed after all. The efficiency of the fuel cell can thus be improved. A separator can in particular be provided connected downstream of the outlet 56 and supplies as large as possible a portion of the excess hydrogen to the side channel pump 20.

(25) The process device 50 of the system of FIG. 13 can, for example, also be a combustion device such as an internal combustion engine. In this respect, the recirculation device 52 forms an exhaust gas return by removing exhaust gas from the mass flow of the outlet 56 and returning it into the supply air flow at the inlet 54.

(26) FIG. 14 shows a system that is closed with respect to the gas flow and that has a process device 50 and a recirculation device 52 having a side channel pump 20. The gas present in the process device 50 can, for example, be circulated via the recirculation device 52 and its side channel pump 20 in order to avoid a phase formation of a gas mixture in the process device.

(27) FIG. 15 shows a further system that is closed with respect to the gas flow. This system likewise comprises a process device 50; a recirculation device 52; and a side channel pump 20. The recirculation device 52 of FIG. 15 additionally comprises a preparation device 58 for preparing the returned gas. The preparation device 58 can, for example, be configured for the purification and/or temperature control of the gas. A preparation device can, for example, be a part of the recirculation device of FIG. 13. To the extent that closed systems are spoken of in connection with the systems of FIGS. 14 and 15, it is understood that the purely schematic drawings do not exclude further gas systems and line systems.

(28) Only embodiments in which the side channels or the side channel pump stages are arranged axially offset are shown in the Figures. It is understood that the side channel pump of the recirculation device in accordance with the invention can also, for example, have radially offset side channel pump stages. A combination of axially and radially offset stages is also possible. Finally, the side channel pump can also be advantageously connected to pump stages that have other pumping principles.

REFERENCE NUMERAL LIST

(29) 20 side channel pump 22 rotor 24 rotor blade 26 side channel 28 shaft 30 stator 32 rotor 34 connection 36 can 38 bearing 40 gap 42 pointed roof-shaped structure 44 ridge edge 46 surface 50 process device 52 recirculation device 54 inlet 56 outlet 58 preparation device