EP3594498A1 - Gas recirculation device and system with same - Google Patents

Abstract

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

Description

The present invention relates to a recirculation device for a gas of a process device comprising a recirculation pump. The invention also relates to a system comprising a process device with a space and / or a line for receiving a gas and a recirculation device for the gas.

Gas recirculations are needed in various technical areas. Gas is usually withdrawn from a larger volume in which a process takes place, processed in a suitable manner and then returned to the process. A pump is used to overcome the pressure losses that occur in the gas ducts and any existing treatment, which can provide the necessary overpressure and volume flow. The properties of the gases or gas mixtures, the general pressure level, the gas volume and the gas temperature are some, but not all, parameters that have to be considered.

Membrane compressors or rotary vane compressors are usually found in such known recirculation devices, sometimes also twin-shaft compressors, such as Roots, screw or claw compressors (the terms "compressor" and "pump" are used synonymously here).

Diaphragm and rotary vane compressors are subject to friction and wear and therefore require regular maintenance. Diaphragm compressors have a pulsating delivery due to discrete delivery volume, poor scalability due to limited speed variability and discrete volumes, wear on bearings, diaphragms, crankshafts, connecting rods and valves as well as vibrations due to the oscillating movement of diaphragms and connecting rods. Depending on the design, rotary vane compressors have oil or abrasion in the pumping chamber, both of which can be disadvantageous for the processes. The limited scalability due to speed due to discrete volumes and friction in the system can also be disadvantageous.

Roots, screw and claw compressors are less subject to wear than non-contact pumps, but the manufacturing costs of these twin-shaft systems with synchronous gears are considerably higher. Root compressors generally have a relatively large size and high costs due to the two-shaft structure with the required synchronization of the shafts. The compression ratio is relatively low with a relatively large volume. As a result, root compressors can only be scaled to a limited extent via speed variation. The efficiency is also relatively low due to considerable gap losses. In addition, the shaft bushings would have to be sealed in a complex manner.

A large number of pumps for gas recirculation are therefore known in the prior art, each of which has specific advantages, but also, as explained, numerous disadvantages.

It is an object of the invention to provide a gas recirculation device which is simple and inexpensive to implement with good effectiveness. In particular, the disadvantages set out above are also to be overcome.

This object is achieved by a recirculation device according to claim 1, and in particular in that the recirculation pump is a side channel pump. The side channel pump has a particularly good effectiveness with a simple and inexpensive design in manufacture and operation.

The side channel technology is particularly advantageous due to its fluid dynamic properties, the almost mechanically frictionless operation and its adaptability to different processes via speed, side channel and rotor blade geometry, number of stages and a large number of available material combinations. The side channel pump works essentially without contact, thus allowing long lifetimes and is almost wear-free. The side channel pump allows a customization and precise adjustment of the provided pressure and flow, e.g. by choosing a single or multi-stage version and / or by speed control. Furthermore, a rotor blade and a side channel shape can be adapted to the gases to be conveyed. Correspondingly resistant materials can be used for corrosive media.

The side channel pump in particular has only one shaft. A multi-stage side channel pump can also be produced with a single shaft, for example with a plurality of rotors which are arranged on one and the same shaft. The side channel pump is thus particularly simple and inexpensive to manufacture.

So far, a large number of pumps has been selected depending on the application, so that the specific advantages have been exploited. The recirculation device according to the invention now allows a particularly good range of applications with a simple structure and low manufacturing and operating costs.

The recirculation device can, for example, have a treatment device for the gas. The processing device can be designed, for example, to purify the gas, to separate or enrich certain gas fractions, to add something to the gas or to make the gas usable or improve it in some other way for a process.

In general, the gas can only be partially returned to the process device. For example, all of the gas removed can be recycled or only a part, in particular a certain component.

The gas can contain or be, for example, hydrogen, temperature control agents, in particular coolants, and / or CO ₂ . Furthermore, for example, the gas can contain or be air, helium and / or neon. In general, the gas is present at least in operation in the process device, in particular a room or a line.

The side channel pump can comprise, for example, at least one rotor with a plurality of rotor blades. It can advantageously be provided that the rotor blades are each at least one of straight, arrow-shaped, curved, divided or connected in the direction of movement, or inclined forwards or backwards in the direction of movement. Combinations of these features per rotor blade, per rotor and / or per pump stage are also advantageous.

A space between two adjacent rotor blades in the direction of movement can, for example, be flat or have a pointed roof-shaped structure. A flat structure is particularly easy to manufacture. A pointed roof-shaped structure supports the vortex formation of the gas to be pumped in the side channel and thus the pumping effect. In this case, a ridge edge or a ridge area can, for example, run essentially parallel to the direction of movement of the blades and / or connect the blades or run obliquely, in particular drop from one blade to a base of an adjacent blade. The pointed roof-shaped structure can have flat and / or curved, in particular concave, side surfaces.

For example, it can be provided that at least one side channel of the side channel pump has an at least substantially circular, oval, elliptical, has rectangular or egg-shaped cross-sectional geometry. Other cross-sectional geometries are also possible, such as rounded and / or trapezoidal cross-sections. In general, the cross-sectional geometry of a side channel can be, for example, symmetrical or else asymmetrical.

According to one embodiment, a side channel of the side channel pump tapers in the flow direction in its cross section, in particular from an inlet of the side channel to an outlet of the side channel. In this way, particularly good compression can be achieved in a simple manner.

In general, a side channel can be interrupted by an interrupter, for example, between the outlet and inlet of the side channel, or the outlet and inlet can be separated from one another by an interrupter.

The side channel pump can preferably be designed in one or more stages, in particular in two, three, four or five stages. The steps can be arranged, for example, axially and / or radially offset. The performance data of the side channel pump, in particular discharge pressure and gas flow, can be easily adapted to a particular application.

The side channel pump can have, for example, a, in particular hermetic, seal, in particular with respect to the surroundings. In particular, the parts of the pump that are movable to produce the pumping action, that is to say in particular the shaft, rotor, motor rotor and / or movable bearing parts, can be arranged inside the seal, that is to say in particular from the environmental point of view behind the seal. The side channel pump can thus be easily designed for use with corrosive media. The moving parts can, for example, be encapsulated for the purpose of sealing.

According to a development, the side channel pump has a motor with a rotor, the rotor being arranged in a space, in particular hermetically sealed from the surroundings. For this purpose, the rotor can in particular be arranged in a tube. For example, the motor can be a canned motor.

In general, the motor can advantageously be a permanent magnet motor, in particular with a permanent magnet rotor.

The speed of the side channel pump can advantageously be controllable via a frequency converter. The side channel pump can thus be particularly easily and precisely adapted to a particular application and also to certain operating conditions during a process.

According to one embodiment, it is provided that a rotor or a rotor shaft of the side channel pump is supported by at least one grease-lubricated bearing. This enables a low-friction bearing run without a complex, additional lubrication system. In addition, the bearing can be carried out with little maintenance and essentially no equipment replacement is necessary, as it might be the case with oil lubrication.

In general, the pump can have a seal, in particular a hermetic seal. All bearings for the rotor shaft are preferably arranged in the area of the recirculated gas, ie from the perspective of the surrounding area behind the seal. Grease-lubricated bearings in particular make it possible for the pump to be sealed as rarely as possible, at best not at all over the service life. As a result, the maintenance outlay can be considerably reduced, since the restoration of an, in particular hermetic, seal is usually very complex and requires special expertise. In addition, certain gases should not come into contact with the environment for various reasons.

This is made significantly easier by a low-maintenance pump. The rotor, rotor shaft, motor rotor and / or bearing are generally preferably arranged in the region of the recirculated gas.

The invention further relates to a system comprising a process device with a space and / or a line for receiving a gas and a recirculation device according to the type described above, by means of which the gas can be removed from the process device and returned to the process device.

The process device is generally designed to carry out a process, the gas being relevant to the process in some way. In general, the gas does not have to be part of the process. The gas can also only act catalytically or otherwise, e.g. be a tempering medium. The gas can be an essentially pure gas or a gas mixture such as air. In principle, the gas can also contain particles and / or droplets, for example.

The gas can be recycled, for example, for the purpose of processing, for example cleaning, temperature control, separation and / or enrichment. In particular, the recirculation device can have a correspondingly designed treatment device. However, the return can also be returned, for example, essentially without influencing or changing the gas. In general, the gas can be removed, for example, at an outlet of the process device, in particular with only a part of the gas flow being returned at the outlet, and / or the gas can, for example, be returned to an inlet of the process device, in particular with a further gas flow entering the inlet.

In particular, the system can be a closed system and / or a closed gas circuit can be provided.

The advantages of the invention are particularly evident in a process device that comprises a laser. The laser can preferably be a gas laser, in particular an excimer or CO ₂ laser.

A process device that includes a temperature control device, in particular an air conditioning and / or cooling device, is also advantageous. For example, gas recirculation can be effected by means of the recirculation device. In this way, the temperature control effect of the device can be improved, the advantages according to the invention being used particularly well.

The process device can comprise, for example, a fuel cell, which e.g. can be used to generate electricity, for example to drive a vehicle engine. The recirculation device can advantageously be arranged to recycle excess process gas from the fuel cell, in particular hydrogen.

According to a further advantageous example, the process device comprises a combustion device, in particular an internal combustion engine, for example a vehicle drive. The recirculation device can be arranged, for example, for returning an exhaust gas from the combustion device, in particular to an inlet of the combustion device.

In general, the process device can therefore advantageously be part of a vehicle drive. In general, the process device can further comprise, for example, any type of reactor, for example a fuel cell or combustion device, with at least partially gaseous output.

Finally, all of the embodiments and individual features described for the recirculation device can be used for advantageous further development of the system and vice versa.

The invention also relates to the use of a side channel pump as a recirculation pump of a recirculation device for a gas of a process device, in particular a recirculation device according to the invention as disclosed herein, and in particular a recirculation device which is a component of a system according to the invention as disclosed herein.

Fig. 1

zeigt eine Seitenkanalpumpe in perspektivischer Ansicht.

Fig. 2

zeigt die Seitenkanalpumpe der Fig. 1 in einer Schnittansicht.

Fig. 3

zeigt eine weitere Seitenkanalpumpe in perspektivischer Ansicht.

Fig. 4

zeigt die Seitenkanalpumpe der Fig. 3 in einer Schnittansicht.

Fig. 5

zeigt eine dritte Ausführungsform einer Seitenkanalpumpe in einer perspektivischen Schnittansicht.

Fig. 6

zeigt einen gegenüber Fig. 5 vergrößerten Teilbereich der Seitenkanalpumpe in Schnittansicht.

Fig. 7 bis 12

zeigen verschiedene Ausführungsformen von Rotoren für eine Seitenkanalpumpe.

Fig. 13 bis 15

zeigen verschiedene Systeme mit Prozesseinrichtung und Rezirkulationseinrichtung.

The invention is explained below by way of example only with reference to the schematic drawing.

Fig. 1

shows a side channel pump in perspective view.

Fig. 2

shows the side channel pump of the Fig. 1 in a sectional view.

Fig. 3

shows a further side channel pump in a perspective view.

Fig. 4

shows the side channel pump of the Fig. 3 in a sectional view.

Fig. 5

shows a third embodiment of a side channel pump in a perspective sectional view.

Fig. 6

shows one opposite Fig. 5 enlarged section of the side channel pump in sectional view.

7 to 12

show different embodiments of rotors for a side channel pump.

13 to 15

show different systems with process equipment and recirculation equipment.

Fig. 1 shows a side channel pump 20 for use as a recirculation pump in a recirculation device according to the invention for a gas of a process device. In the upper area, the pump 20 is free, so that a rotor 22 is visible, which rotates to provide a pumping effect. Out Fig. 2 it can be seen that the pump 20 has only one rotor 22, that is to say it has a single stage. The rotor 22 rotates with a plurality of rotor blades 24 distributed over its circumference in a side channel 26. The side channel 26 is an annular channel which is somewhat larger in cross section than a respective rotor blade. In the present embodiment, the side channel 26 is essentially rectangular in cross section, but with rounded corners.

The rotor 22 is arranged on a shaft 28 of the side channel pump 20. The shaft 28 and thus the rotor 22 are driven in rotation by an electric motor which 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 fixed to the shaft 28. The shaft 28 and thus the rotor 22 are thus driven directly by the electric motor 30, 32.

In this embodiment, the rotor 22 is designed with curved rotor blades 24 that are inclined slightly backwards in the direction of movement and with a flat space between the rotor blades 24.

The 3 and 4 show a two-stage side channel pump 20 which has two rotors 22.1 and 22.2, which are on a common shaft 28 are stored. The rotors 22.1 and 22.2 rotate in respective side channels 26.1 and 26.2, which here also have an essentially rectangular cross section. At the top of the Fig. 4 a connection 34 of the side channels 26.1 and 26.2 is visible.

The rotors 22.1 and 22.2 each have arrow-shaped blades 24 which are inclined slightly backwards in the direction of movement. In the spaces between the blades 24, the rotor 22 is designed to be flat. The direction of movement here preferably runs in the direction of the tips of the respective arrow-shaped blades 24. In principle, however, reverse operation is also possible, for example.

The shaft 28, which supports the rotors 22, is driven by an electric motor. The electric motor has a stator 30 with windings and a permanent magnetic rotor 32 which sits on the shaft 28. The rotor 32 or the shaft 28 are arranged within a tube 36, which is part of a hermetic seal of the pump 20. Such a tube 36 is also referred to as a can, since it extends through the gap between the rotor 32 and the stator 30 of the electric motor. Accordingly, the electric motor is called a canned motor. The can 36 can be made of glass fiber composite, for example. From an environmental point of view, the rotor 32 or the shaft 28 are therefore located behind the hermetic seal and in an area which is essentially permeated by the gas to be pumped and has a corresponding pressure level.

There are also two bearings 38 behind the seal or in the area of the gas to be pumped. These are preferably grease and / or permanently lubricated.

The functional elements arranged in the gas area or behind the seal are therefore essentially independently functional. In particular, they have to are not wired, such as with electricity or equipment. The rotors 22 also run in a contactless manner in the housing gaps 40 provided for them. The functional parts in the gas area are therefore extremely low-wear and low-maintenance. The hermetic seal of the pump 20 therefore only has to be released very rarely during dismantling in order to service the pump.

A third embodiment of a side channel pump 20 is shown in FIG Fig. 5 shown. The side channel pump 20 is designed in five stages, so there are five rotors 22 which rotate in respective side channels 26. The rotors 22 are in turn arranged on a common shaft 28. An in Fig. 5 indicated area A of the side channel pump 20 is in Fig. 6 enlarged and shown rotated by 90 degrees.

Out Fig. 6 it can be seen that the side channels 26.1 and 26.2 of the first two pump stages are essentially rectangular, whereas the side channels 26.3, 26.4 and 26.5 of the other pump stages have an essentially oval or egg-shaped cross section. Like it in particular Fig. 5 can be seen, the rotors 22.1 and 22.2 each have curved rotor blades. The rotors 22.3, 22.4 and 22.5, however, are arrow-shaped. The rotors 22.3, 22.4 and 22.5 also have a pointed roof-shaped structure 42 in the respective spaces between adjacent rotor blades 24, which supports the pumping action by favoring vortex formation of the gas flow in the side channel 26.

In the 7 to 12 Various advantageous embodiments of rotors 22 are shown. The rotor 22 of the Fig. 7 has curved rotor blades 24 with flat spaces.

The rotor 22 of the Fig. 8 has flat rotor blades 24 which extend radially. Roof-like structures 42 are provided between the rotor blades 24, a respective ridge edge 44 extends parallel to the direction of movement of the rotor blades 24. The ridge edge 44 connects radially outer ends of the blades 24. These are connected rotor blades 24. The surfaces 46 tapering towards the ridge edge 44 are concave.

The rotors 22 of the 9 to 11 are all arrow-shaped and differ essentially in size and number of blades or relative blade spacing. They also have a roof-like structure 42 with a respective ridge edge 44 in the intermediate spaces between the blades. The ridge edges 44 of the rotors 22 are the 9 and 10 self-curved, whereas the ridge edge 44 in Fig. 11 is essentially straight. All ridge edges 44 of the 9 to 11 extend from a respective blade tip to a base of an adjacent blade. The rotor blades 24 are thus not connected.

The blades 24 of the rotor 22 of the in Fig. 12 Finally, the embodiment shown are curved, and they differ in particular from the embodiment of FIG Fig. 7 differ.

In Fig. 13 A system with a process device 50 and a recirculation device 52 is shown, the recirculation system 52 having a recirculation pump designed 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 to the inlet 54. A further mass flow is also fed to the inlet 54 via a further line. In a similar manner, the outlet 56 is connected both to the recirculation device 52 or the side channel pump 20 and to a further line which receives a partial mass flow of the outlet 56. In the system of Fig. 13 So part of a mass flow that passes through the process device is recirculated. At the process setup 50 can be a fuel cell, for example. In this case, the mass flow can contain hydrogen, for example. Excess hydrogen that was not consumed by the fuel cell is returned to the inlet 54 via the recirculation device 52 so that it is finally consumed. The efficiency of the fuel cell can thus be improved. In particular, a separator can be provided downstream of the outlet 56 and supplies the side channel pump 20 with as much of the excess hydrogen as possible.

The process device 50 of the system of Fig. 13 can, for example, also be a combustion device, such as an internal combustion engine. The recirculation device 52 forms an exhaust gas recirculation by taking exhaust gas from the mass flow of the outlet 56 and returning it to the supply air flow at the inlet 54.

Fig. 14 shows a closed system with regard to the gas flow with process device 50 and recirculation device 52 with side channel pump 20. The gas in process device 50 can be circulated via recirculation device 52 and its side channel pump 20, for example to avoid phase formation of a gas mixture in the process device.

Another closed system with regard to the gas flow is shown in FIG Fig. 15 , This system also includes a process device 50, a recirculation device 52 and a side channel pump 20. The recirculation device 52 of FIG Fig. 15 also includes a processing device 58 for processing the returned gas. The processing device 58 can be designed, for example, for cleaning and / or tempering the gas. A processing device can, for example, be part of the recirculation device Fig. 13 his. To that extent in connection with the systems of 14 and 15 of closed systems, it is understood that the pure schematic drawings do not exclude other gas and piping systems.

In the figures, only embodiments are shown in which the side channels or the side channel pump stages are arranged axially offset. It goes without saying that the side channel pump of the recirculation device according to the invention can also have, for example, radially offset side channel pump stages. A combination of axially and radially offset stages is also possible. Finally, the side channel pump can also advantageously be connected to pump stages which have different pumping principles.

LIST OF REFERENCE NUMBERS

20

Side channel pump

22

rotor

24

rotor blade

26

side channel

28

wave

30

stand

32

runner

34

connection

36

canned

38

camp

40

gap

42

pointed roof-shaped structure

44

First edge

46

area

50

process means

52

recirculation

54

inlet

56

outlet

58

conditioning device

Claims (15)

Recirculation device (52) for a gas of a process device (50) comprising a recirculation pump,
wherein the recirculation pump is a side channel pump (20). Recirculation device (52) according to claim 1,
wherein the gas contains hydrogen, a temperature control agent and / or CO ₂ . Recirculation device (52) according to one of the preceding claims, wherein the side channel pump (20) comprises at least one rotor (22) with a plurality of rotor blades (24), and wherein the rotor blades (24) each have at least one of straight, oblique, arrow-shaped, curved , divided, undivided, or inclined forward or backward in the direction of movement. Recirculation device (52) according to one of the preceding claims, wherein the side channel pump (20) comprises at least one rotor (22) with a plurality of rotor blades (24), and wherein an intermediate space between two adjacent rotor blades (24) is flat or a pointed roof Has structure (42). Recirculation device (52) according to one of the preceding claims, wherein at least one side channel (26) of the side channel pump (20) has a circular, oval, elliptical, rectangular or egg-shaped cross-sectional geometry. Recirculation device (52) according to one of the preceding claims, wherein at least one side channel (26) of the side channel pump (20) tapers in its flow direction in its cross section. Recirculation device (52) according to any one of the preceding claims, wherein the side channel pump (20) is designed in one or more stages. Recirculation device (52) according to one of the preceding claims, wherein the side channel pump (20) has a seal, and wherein the parts of the pump (20) which are movable to produce the pumping action are arranged within the seal. Recirculation device (52) according to one of the preceding claims, wherein the speed of the side channel pump (20) can be controlled via a frequency converter. Recirculation device according to one of the preceding claims, wherein a rotor (24) of the side channel pump (20) is supported by at least one grease-lubricated bearing (38). Comprehensive system
a process device (50) with a space and / or a line for receiving a gas and
a recirculation device (52) according to one of the preceding claims, by means of which the gas can be removed from the process device (50) and returned to the process device (52), in particular with a closed gas circuit being provided. System according to claim 11,
wherein the process device (50) comprises a laser. System according to claim 11 or 12,
wherein the process device (50) comprises a temperature control device. System according to one of claims 11 to 13,
wherein the process device (50) comprises a fuel cell. System according to one of claims 11 to 14,
wherein the process device (50) comprises a combustion device.

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