EP1571341B1 - Multistage vacuum fan - Google Patents

Abstract

The suction blower has at least two radial fans (3,3a,3b) with flywheels and connected together through a flow channel (8). The radial fans are mounted off-set relative to each other on separate drive shafts (4, 4a, 4b) so that the flow deflection is less than 180 degrees in the flow channel between the outlet opening (6a) of the first and the intake opening (7a) of the second fan. The drive shafts can be mounted floating at their ends mounted in the radial fans but each individual drive shaft does not project over the end side of the flywheel facing the intake opening.

Description

Technical area:

The invention relates to a suction dredger with a multi-stage suction fan with at least two, each consisting of a housing and an impeller arranged therein, successively arranged, drivable radial blowers, wherein the blowout of the respective first radial blower is connected to the intake of the respective second radial blower through a respective flow channel ,

State of the art:

Recent developments for digging trenches, canals, and the like are to use, instead of a conventional bucket-equipped excavator, a suction dredge having a suction fan that generates a vacuum strong enough to penetrate soil and the like to suck a suction hose or a suction pipe into a collecting tank. Such a suction dredger is for example by the EP 1 127 196 A1 has become known which has a pneumatic suction turbine which is connected to a collecting container for the sucked up suction material and with a collecting container subsequent filter chamber with a plurality of filters through which the suction air flow is passed for fine filtration, said collecting container and filter chamber separated by a partition are. The mouth of the suction pipe takes place laterally above in the sump, wherein the passage of the partition opposite the confluence of the suction pipe is arranged offset by 180 degrees and within the partition as far as possible away from the junction, so that the Saugluftströmung about a vertical axis moved cyclone within the collecting container, and the suction air flow is guided so that it flows against the filter in the filter chamber substantially horizontally and flows through it.

For such suction fan radial blower are particularly suitable due to the required power range between about 100 and 1000 kW and because of the required resistance to alternating loads, shocks and dirt particles in the intake air. These have in addition to axial fans in addition to the advantage that they are easy to produce and have a lower maintenance.

A radial fan consists of a arranged in a housing on a drivable drive shaft impeller, which consists of a flat, arranged perpendicular to the longitudinal axis of the drive shaft in the center, circular disc and arranged perpendicularly on the disc wings, wherein the housing at least one aligned with the drive shaft or Having arranged in the vicinity of the longitudinal axis of the drive shaft suction opening and at least one arranged in the housing in the region of the outer periphery of the impeller exhaust opening. The centrifugal fan utilizes the inertia of the air by centrally flowing air through the suction port into the impeller and rotating it through the vanes located on the rotating disk so that the air is thrown radially outward due to its inertia and thereby compressed. The compressed air flows out through the arranged in the housing in the region of the outer periphery of the impeller exhaust opening from the radial fan. If the blower operates at the exhaust opening against ambient pressure, a negative pressure relative to the ambient pressure is generated at the intake opening.

Due to slit flows, compressibility effects, resonance effects, the occurring Reynolds number and the like, it is not possible to generate any desired pressure ratio between the blow-out and intake openings with a blower, irrespective of whether it is a radial blower or an axial blower.

To increase the pressure ratio that can be generated, it is therefore customary to arrange a plurality of radial fans on a common, drivable drive shaft one behind the other, wherein, for example, in a two-stage suction fan, the exhaust opening of the first stage serving as the first radial blower with the suction port of serving as a second stage second radial blower is connected. In several stages, these are just as much as the first and the second stage each connected between the exhaust port and suction through a flow channel.

However, such a multi-stage radial blower have the disadvantage that due to the principle of operation - arranged in the axial direction in the drive shaft inlet opening and arranged radially in the housing in the region of the outer periphery of the impeller exhaust opening - a flow deflection at first at least 180 ° towards the drive shaft and then at least 90 ° in a direction parallel to the drive shaft, together so at least 270 °, is required to connect the exhaust port of the previous stage with the intake port of the subsequent stage, resulting in very high energy losses in the flow and the maximum achievable pressure ratio is lowered.

In addition, the common drive shaft must be passed through the flow channel between the stages due to the respectively axially arranged in the axis intake opening of the individual stages, thereby causing additional energy losses, the maximum achievable pressure ratio further lowering, undesirable cross-sectional changes in the inlet channel.

An additional disadvantage of the known arrangement is that an adaptation of the suction power is only possible via a speed adjustment of the radial fan. Such an adaptation is appropriate, for example, depending on the aufzusaugendem bulk material, or of its moisture or state, as for example, the power consumption and thus the energy consumption can be lowered. The known from the prior art embodiments allow only a limited reduction in energy consumption, since the effectiveness of a radial fan, as usual in turbomachinery, is limited to a narrow speed range, so that the power consumption with an adjustment of the suction power over the speed is not linear with the suction power changed.

By the DE 295 04 886 U1 , Which is considered as the closest prior art, is a venting device, in particular for garages or similar spaces with high air pollutants, known, with two fluidically optional successive or with mutual bypass arranged, driven radial fans or fans, wherein the exhaust opening of the first radial fan with the suction port of the second radial fan through a flow channel is selectively connectable. The radial fans arranged in succession and connectable to one another by a flow channel are arranged offset relative to one another on two separate drive shafts, so that a flow deflection of 90 °, ie less than 180 °, in the flow channel between the blow-off opening of the first and the suction opening of the second radial blower. he follows. The two radial fans are bypassing the other radial fan alone in the Luftförderweg switched on or in such a way switchable that the air inlet of the second radial blower in the conveying direction is connected to the downstream side of the first radial fan. The fans are preferably axial fans, the rotors of which are designed for opposite directions of rotation and are driven in opposite directions.

However, this deaerator is not suitable for use in a suction dredger. The achievable with this venting device pressure ratio, which can only be achieved even when connecting the two radial blower in series, is not enough to dig by means of a suction dredge, for example, trenches or the like.

By the GB 2 231 009 A For example, a device for deflecting the fluid flow of an engine for a two-jet, vertically launchable aircraft has become known. During a vertical takeoff or in hover, in normal operation, ie both engines are active, a part of the fluid flow of the respective first compressor stage, which is a bypass engine or a turboprop engine, the two engines by separate outlet nozzles with adjustable outlet cross-section vertically deflected downward. Each engine is responsible for the lift on the respective side of the aircraft. Falls an engine During this phase of flight, the device allows bypassing the failed engine to divert the branched fluid flow of the still active engine also to the outlet nozzle of the failed engine. The device thus allows a safety measure during the critical hover phase of a twin-jet vertically launching aircraft in case of failure of an engine by deflecting a portion of the fluid flow of the still active engine through the exhaust nozzle of the failed engine to prevent crashes of the aircraft, without this fluid flow through the failed engine passes through. Here, the respective first compressor stages of the two engines are arranged in the flow direction parallel to each other, wherein the nozzle (blow-out) of the first engine does not open into the inlet (intake) of the second engine.

Technical object of the invention:

The invention is therefore based on the object to develop a suction dredger, which uses the advantages of radial blowers, without having at least all of the aforementioned disadvantages, so that an improvement in the efficiency of the suction fan of the suction dredger can be achieved.

Disclosure of the invention and its advantages:

The object is achieved in a suction dredger of the aforementioned type in that the successively arranged and each interconnected by a flow channel radial fan are arranged offset relative to each other on separate drive shafts, so that in the flow channel between the exhaust opening of the first and the suction of the second Radial blower a flow deflection by less than 180 ° (degrees) takes place. Preferably, a flow deflection of 90 ° (degrees) takes place in the flow channel between the blow-out opening of the first and the suction opening of the second radial blower.

It is also possible that more than two radial blowers, which are also to be referred to as stages, are connected in series, wherein in the flow passage between the blowout of the first and preceding and the suction of the second and subsequent radial blower, a flow deflection preferably by 90 ° (Degrees). The series connection of the stages can thus take place in such a way that the individual stages follow one another in a step-like manner, so that it is ensured for each stage that a flow deflection of 90 ° is provided between the discharge opening of the preceding stage and the suction opening of the subsequent stage.

The suction fan according to the invention has the advantage over the prior art, that at least two radially arranged successively arranged and each interconnected by a flow passage radial fan relative to each other on separate drive shafts are arranged so that in the flow channel between the exhaust opening of the first and the suction of the second radial fan flow deflection by less than 180 °, preferably 90 °, takes place. Two successive radial fans are so far offset relative to each other perpendicular to at least one longitudinal axis of the two drive shafts arranged that the suction of the second radial blower at least half the diameter of the housing of the first radial fan perpendicular to the drive shaft of the latter and in the direction of at least one longitudinal axis of the two Drive shafts is arranged offset, so that when parallel drive shafts, a flow deflection between the blowout of the first radial blower and the suction of the second radial blower by only 90 ° is required, which can significantly increase the efficiency and the maximum achievable pressure ratio of the suction fan. In non-parallel drive shafts of the two radial fan, the necessary flow deflection is changed by an additional included between the drive shafts angle.

An advantageous embodiment of the invention provides that do not intersect the longitudinal axes of the drive shafts in their projection on each other. A further advantageous embodiment of the invention provides that the drive shafts are arranged parallel to each other.

In a further advantageous embodiment of the invention, the drive shafts of the radial fan are mounted on their respective arranged in a radial fan end flying, each individual drive shaft does not protrude beyond the inlet opening facing the arranged in the housing of the respective radial fan impeller, so that the drive shaft is not through the cross section of the suction leads. Due to the floating bearing, it is possible to dispense with interfering internals for supporting the drive shaft in the cross-section of the intake opening, thereby reducing the losses in the flow before entering the radial fan.

Another advantageous embodiment of the invention provides that the rotational speeds of the drive shafts are independently controllable, so that a Adjustment of the speed of each fluidically consecutive radial blower to the thermodynamic state of the delivered air is possible, given by the total pressure, the static pressure and the density of the air in the cross section of the intake of the respective radial fan.

An additional advantageous embodiment of the invention provides that the drive shafts of the radial fan are at least in groups independently drivable, wherein in the flow channel between two fluidically successive, independently drivable radial blowers or radial fan groups a closable blow-off is arranged, through which air if necessary at least one driven radial fan or a driven centrifugal fan group can be blown off in front of at least one non-driven radial fan or a non-driven centrifugal fan group into the environment. By individually or in groups independently driven radial fan adjustment of the suction power of the suction fan can be made, with the blowing off of the air between driven and non-driven radial fans no energy for the flow through the non-driven, shut down radial fan or centrifugal fan groups must be applied.

A particularly advantageous embodiment of the invention provides that the radial fan are arranged on two drive shafts, wherein fluidically successive radial fan are arranged alternately each on a different of the two drive shafts, as the respectively before and then lying radial fan. For example, in the case of a six-stage suction fan, the first, third and fifth radial fans are arranged on a first drive shaft, and the second, fourth and sixth radial fans are arranged on a second drive shaft arranged offset in parallel, the radial fans arranged on a drive shaft in each case in the intermediate space between the radial fans the other drive shaft are arranged. In this arrangement, although the respective common drive shaft through the cross section of the intake of individual radial blower, resulting in losses in the flow, but this is at least partially compensated by a very compact and simple structure.

An advantageous embodiment of the invention provides that at least two identical suction fan, each with at least two successive radial fans are successively arranged to form a fan, wherein the intake of the first radial fan of the second suction fan with the exhaust opening of the last radial fan of the first suction fan by a closable discharge opening having connecting channel is connected, wherein the suction fan are independently switched on and off. Within a suction fan to achieve the highest possible efficiency as far as possible causes a minimum and at most technically necessary flow deflection between the individual radial fans, whereas between the independent and sequentially arranged suction fans, for example due to a limited space, a stronger flow deflection may be necessary. By the successive arrangement of several identical suction fan, the degree of freedom in the design and adaptation of such suction fan can be increased to different application and space situations.

In a further inventive embodiment of the suction dredger at least four each consisting of a radial fan blower stages are present, each two or possibly three successively and each connected by a flow channel interconnected and offset relative to each other on separate drive shafts are arranged so that in the flow channel between the Ausblasöffnung the first and the suction of the second radial fan and optionally the third radial fan a flow deflection by less than 180 ° (degrees), preferably by 90 ° (degrees), takes place and these stages form a first stage block, wherein this step block is followed by at least one further step block, which is rotated 180 ° with respect to the first step block, wherein between the exhaust port of the last stage of the first stage block and the suction port of the first stage of the other, adjacent step block, a flow deflection of 270 °, however the flow deflections within the individual step blocks are less than 180 ° (degrees), preferably 90 ° (degrees).

In a further embodiment of the patented suction dredger, the offset between two successive radial fans of a step block perpendicular to the longitudinal axes of the drive shafts chosen so large that the intake of the second and optionally third radial fan at least at a distance "s" from the longitudinal axis of the drive shaft of the first and optionally second radial fan is arranged remotely, which corresponds to half the diameter of the housing of the first radial fan and is offset in the direction of the longitudinal axes of the drive shafts by the length of the housing.

Figur 1

eine schematische Anordnung eines Sauggebläses in der Draufsicht mit zwei auf getrennten, parallel verlaufenden und getrennt auch antreibbaren Antriebswellen angeordneten Radialgebläsen,

Figur 2

eine schematische Anordnung in der Draufsicht auf einen zwei identische Sauggebläse zu einem Gebläse verbindenden Verbindungskanal mit einer verschließbaren Abblasöffnung,

Figur 3

eine Seitenansicht eines Saugbaggers mit einem Gebläse bestehend aus zwei identischen, getrennt zu- und abschaltbaren Sauggebläsen mit jeweils zwei auf getrennten, parallel verlaufenden Antriebswellen angeordneten Radialgebläsen im Röntgenblick,

Figur 4

eine Detailansicht des Gebläses von Figur 3 in der Seitenansicht,

Figur 5

eine Draufsicht eines Saugbaggers mit einem Gebläse bestehend aus zwei identischen, getrennt zu- und abschaltbaren Sauggebläsen mit jeweils zwei auf getrennten, parallel verlaufenden Antriebswellen angeordneten Radialgebläsen im Röntgenblick,

Figur 6

einen Querschnitt durch einen Saugbagger mit einem Gebläse bestehend aus zwei identischen, getrennt zu- und abschaltbaren Sauggebläsen mit jeweils zwei auf getrennten, parallel verlaufenden Antriebswellen angeordneten Radialgebläsen im Röntgenblick, sowie

Figur 7

eine schematische Anordnung eines Sauggebläses in der Draufsicht mit vier auf getrennten parallel verlaufenden und getrennt antreibbaren Antriebswellen angeordneten Radialgebläsen, welche somit vier Stufen ausbilden.

Brief description of the drawing, in which:

FIG. 1

a schematic arrangement of a suction fan in plan view with two on separate, parallel and arranged separately driven drive shafts radial blowers,

FIG. 2

1 shows a schematic arrangement in the plan view of a connection channel connecting a blower with two identical suction blowers with a closable blow-off opening;

FIG. 3

a side view of a suction dredger with a blower consisting of two identical, separately switched on and off suction fans with two on separate, parallel drive shafts arranged radial fans in the X-ray view,

FIG. 4

a detailed view of the blower of FIG. 3 in the side view,

FIG. 5

a top view of a suction dredger with a blower consisting of two identical, separately switched on and off suction fans with two on separate, parallel drive shafts arranged radial fans in the X-ray view,

FIG. 6

a cross section through a suction dredger with a blower consisting of two identical, separately switched on and off suction fans with two each on separate, parallel drive shafts arranged radial fans in the X-ray view, and

FIG. 7

a schematic arrangement of a suction fan in plan view with four arranged on separate parallel and separately driven drive shafts radial blowers, which thus form four stages.

Ways to carry out the invention:

An in FIG. 1 schematically illustrated suction fan 2 consists of two spaced-apart, parallel drive shafts 4 staggered and successive radial fans 3a and 3b, stages, which can be summarized referred to as a step block. Each radial blower 3a, 3b has on its housing 25 in the longitudinal axis 5a, 5b of the respective drive shaft 4a, 4b arranged centrally leading to an impeller 11 intake opening 7a, 7b, and in the housing 25 of the radial fan 3a, 3b, in the region of Outside circumference of the impeller 11 arranged exhaust opening 6a, 6b. The blow-off opening 6a of the first radial blower 3a and the suction opening 7b of the second radial blower 3b connects to a flow channel 8, which causes a deflection of the air flow by 90 degrees.

The offset "s" between the radial fans 3 a, b within the suction fan 2 both in the direction of the longitudinal axes 5a, 5b of the drive shafts 4a, 4b is chosen so that between the exhaust opening 6a of the first radial fan 3a and the suction port 7b of the second radial fan 3b a flow deflection of only 90 ° is necessary by the offset between the successive radial fans 3a and 3b perpendicular to the longitudinal axes 5a, 5b of the two drive shafts 4a, 4b is chosen so large that the suction port 7b of the second radial fan 3b at least at a distance is arranged away from the longitudinal axis 5a of the drive shaft 4a of the first radial fan 3a, which corresponds to half the diameter of the housing 25 of the first radial fan 3a, and in the direction of the longitudinal axes 5a, 5b of the two drive shafts 4a, 4 b is offset by the length of the housing 25, resulting in a significant increase in efficiency over the prior art, according to which a deflection of at least 270 ° is required results.

The drive shafts 4 a, b are also mounted on their flying ends connected to the radial fans 3 a, b 9, wherein each individual drive shaft 4 a, b not on the suction opening 7 facing end face 10 of the arranged in the respective radial fan 3 impeller eleventh protrudes. Due to the flying bearing no flow interfering internals for supporting the drive shaft 4 in the intake is required, in addition, the drive shafts 4 do not protrude into the cross section of the intake 7, thereby further improving the efficiency of the suction fan 2 is effected by reducing the flow losses , The working direction of the suction fan 2 is indicated by the flow direction S.

In FIG. 2 a connection channel 12 is shown, with the two identical suction fan 2 of the FIG. 1 to a suction power in the two-stage controllable suction fan 1, FIG. 3 , can be connected. The connecting channel 12 has a closable by a door 14 Abblasöffnung 13, which allows air, which has been promoted by a suction fan, redirect so that it does not by a second, for example, switched off suction fan, or other suction fan flows. The connecting channel 12, together with the closable blow-off opening 13, enables the connection of two or more than two identical suction blowers 2, wherein the suction blowers 2 can be switched on and off independently of one another. As a result, an adaptation of the suction power of the blower 1 to the respective power requirement, which is different, for example, when vacuuming dry or damp soil, possible. The exhaust port 6b of the first, as in FIG. 1 constructed suction blower 2 leads directly into the connecting channel 12, which is separated by means of a partition wall 15 of a silencer 16 connected to the environment. The blow-off opening 13 is cut out of the partition wall 15 and can be closed by the door 14, which is preferably a sliding door or slatted door. Is the door 14 locked, so the air can only through a supply channel 1 7, the second, also as in FIG. 1 shown constructed suction fan 2 leads, flow out. On the side facing away from the connecting channel 12 side of the partition wall 15, the exhaust port 6b of the second suction fan 2 opens before the muffler 16, through which the air can escape into the environment. When the door 14 is open, the air flows directly through the blow-off opening 13 and the silencer 16 into the environment.

In FIG. 3 a suction dredge 18 is shown, consisting of a mounted on a chassis 19 Sauggebläseeinrichtung 1, namely of at least two identical, in their construction FIG. 1 corresponding and connected to a connecting channel 12 suction fans 2, and a collecting container 20 for the sucked soil. In the upper part of the blower 1 is the connecting channel 12, which is separated by the partition wall 15 from the muffler 16. The door 14 closes in FIG. 3 the blow-off opening 13, so that both suction fan 2 can be operated in series to produce a high suction power.

In FIG. 4 is shown mounted on the chassis suction fan device 1, consisting of at least two identical and connected by a connecting channel 12 suction fans 2. It can be seen how the drive shafts 4 of the radial fan 3 means - for example - belt 21 arranged on the drive train 22, not drawn, independent PTO can be driven by the motor 23 of the chassis 19, the PTOs can be switched on and off independently and the chassis 19, while the engine power is mainly needed for the radial blower 3, in the creeper of the suction dredger can be moved forward.

FIG. 5 clearly shows the offset perpendicular to the longitudinal axes 5 and in the direction of the longitudinal axes 5 of the drive shafts 4 between the radial fans 3 within the independent suction fan second

In FIG. 6 is the drive of parallel staggered and each associated with a radial fan 3 drive shafts 4 of the radial fan 3 from the drive train 22 of the chassis 19 can be seen. The drive shafts 4 of the combined into one group radial fan 3 of a suction fan 2 are thereby driven by jointly on a shaft, and driven by the motor 23 of the chassis 19 each group driving wheels 24 driven.

Figur.7 shows a schematic arrangement of a suction fan in plan view with four on separate, parallel and arranged separately driven drive shafts radial blowers, which thus form four stages. Two steps each are combined to form a step block, namely steps 1 and 2 and steps 3 and 4. The design of the individual step blocks, steps 1 and 2 and steps 3 and 4, is very similar to steps 1 and 2 of FIG. 1 , which is why reference is made to the description there. Stages 3 and 4 can thus be understood as a doubling of stages 1 and 2.

The second stage output is connected via a flow channel 8 'to the third stage input; the output of the third stage is connected via a flow channel 8 to the input of the fourth stage. After the output 6d of the fourth stage further stages can be connected. It can be seen that even with the use of four stages an extremely compact design of the radial fan is given.

In FIG. 7 Thus, at least four radial blower 3a, 3b, 3c, 3d are present, each two or optionally three successively and in each case by a flow channel 8 connected and offset relative to each other on separate drive shafts 4 , 4a, 4b, 4c, 4d are arranged, so that in the flow channel 8 between the exhaust port 6, 6a of the first and the suction port 7 of the second radial fan 3, 3a, 3b, a flow deflection of 90 ° (° = degrees) takes place; these stages 1 and 2 form a first stage block. This step block is followed by at least one more Stepped block, formed by the steps 3 and 4, which is rotated relative to the first step block by 180 °. Between the blow-off opening of the last stage 2 of the first stage block and the suction opening of the first stage 3 of the further, adjacent stage block, a flow deflection of 270 ° takes place through the flow channel 8 '; the flow deflections within the individual step blocks are less than 180 °, preferably 90 °, as in FIG. 7 shown.

Industrial Applicability:

The invention is particularly applicable industrially in the field of manufacturing and operation of suction dredgers.

LIST OF REFERENCE NUMBERS:

1

Sauggebläseeinrichtung

2

aspirator

3, 3a, 3b

centrifugal blower

4, 4a, 4b

drive shaft

5, 5a, 5b

Longitudinal axis of the drive shaft

6, 6a, 6b

exhaust vent

7, 7a, 7b

Intake vent

8, 8 '

flow channel

9

flying end of the drive shaft

10

front

11

impeller

12

connecting channel

13

blow-off

14

door

15

partition wall

16

silencer

17

feed channel

18

Saugbagger

19

chassis

20

Clippings

21

belt

22

powertrain

23

engine

24

pinion

25

casing

S

flow direction

s

"s" half the diameter of the housing of the first radial fan

Claims (12)

1. A suction dredge (18) with a multistage suction fan having at least two driven radial fans which are arranged consecutively and which each consist of a housing and of an impeller arranged therein, whereby the exhaust opening of each first radial fan is connected to the intake opening of each second radial fan via a flow channel, and whereby the radial fans (3, 3a, 3b), which are arranged consecutively and which are connected to each other via a flow channel (8, 8'), are offset with respect to each other and are arranged on separate drive shafts (4, 4a, 4b), so that the flow in the flow channel (8) between the exhaust opening (6, 6a) of the first or preceding radial fan (3, 3a, 3b) and the intake opening (7) of the second or subsequent radial fan (3, 3a, 3b) is deflected by less than 180°.
2. The suction dredge according to Claim 1, characterized in that the longitudinal axes (5, 5a, 5b) of the drive shafts (4, 4a, 4b) do not intersect in the projection.
3. The suction dredge according to Claim 2, characterized in that the drive shafts (4, 4a, 4b) are arranged parallel to each other.
4. The suction dredge according to one of Claims 1 to 3, characterized in that the drive shafts (4, 4a, 4b) of the radial fans (3, 3a, 3b) are overhung at their ends (9) that are arranged in a radial fan (3, 3a, 3b), whereby each individual drive shaft (4, 4a, 4b) does not extend beyond the face (10) of the impeller (11) that faces the intake opening, said impeller (11) being arranged in the housing (25) of the appertaining radial fan (3, 3a, 3b).
5. The suction dredge according to one of the preceding claims, characterized in that the speeds of the drive shafts (4, 4a, 4b) can be regulated independently of each other, at least partially.
6. The suction dredge according to one of the preceding claims, characterized in that the drive shafts (4, 4a, 4b) of the radial fan (3, 3a, 3b) can be driven independently of each other, at least in groups, whereby a closeable exhaust opening (13) is arranged in the flow channel (8) between two consecutive radial fans (3, 3a, 3b) or radial fan groups (2) that can be driven separately from each other, so that air can be vented to the environment through said closeable exhaust opening (13) downstream from at least one driven radial fan (3, 3a, 3b) or driven radial fan group (2) and upstream from at least one non-driven radial fan (3, 3a, 3b) or non-driven radial fan group (2).
7. The suction dredge according to Claim 1, characterized in that the radial fans (3, 3a, 3b) are arranged on two drive shafts (4, 4a, 4b), whereby consecutively arranged radial fans (3, 3a, 3b) are each arranged alternately on a different drive shaft of the two drive shafts (4, 4a, 4b) than the preceding radial fan (3, 3a, 3b) and the following radial fan (3, 3a, 3b).
8. The suction dredge according to one of the preceding claims, characterized in that at least two identical suction fans (2) are arranged consecutively in terms of their flow, whereby the intake opening (7, 7a) of the first radial fan (3, 3a) of the second suction fan (2) is connected to the exhaust opening (6, 6a) of the last radial fan (3, 3a) of the first suction fan (2) via a connection channel (12) having a closeable exhaust opening (13), whereby the suction fans (2) can be switched on and off independently of each other.
9. The suction dredge according to one of Claims 5 to 8, characterized in that the drive shafts (4, 4a, 4b) of the radial fans (3, 3a, 3b) can be driven by independent power take-off shafts that are driven by a motor (23) on the chassis (19) of the suction dredge (18).
10. The suction dredge according to Claim 1, characterized in that the flow in the flow channel (8) between the exhaust opening (6, 6a) of the first or preceding radial fan (3, 3a, 3b) and the intake opening (7) of the second or subsequent radial fan (3, 3a, 3b) is deflected by 90°.
11. The suction dredge according to Claim 1, characterized in that at least four fan stages, each consisting of a radial fan (3, 3a, 3b), are present, whereby in each case, two or optionally three consecutive drive shafts (4, 4a, 4b) that are connected to each other via a flow channel (8) and that are arranged offset with respect to each other on separate drive shafts (4, 4a, 4b), so that the flow in the flow channel (8) between the exhaust opening (6, 6a) of the first radial fan (3, 3a, 3b) and the intake opening (7) of the second radial fan (3, 3a, 3b) and optionally of the third radial fan is deflected by less than 180°, preferably by 90°, and these stages form a first stage block, whereby this stage block is followed by at least one additional stage block that is rotated relative to the first stage block by 180°, whereby the flow between the exhaust opening of the last stage of the first stage block and the intake opening of the first stage of the additional, adjacent stage block is deflected by 270°, but the flow within the individual stage blocks is deflected by less than 180°, preferably by 90°.
12. The suction dredge according to Claim 10, characterized in that the offset between two consecutive radial fans (3a, 3b) of a stage block perpendicular to the longitudinal axes (5a, 5b) of the drive shafts (4a, 4b) is selected to be of such a magnitude that the intake opening (7b) of the second and optionally of the third radial fan (3b) is arranged at least at a distance "s" away from the longitudinal axis (5a) of the drive shaft (4a) of the first and optionally second radial fan (3a), said offset corresponding to half of the diameter of the housing (25) of the first radial fan (3a), and being arranged offset in the direction of the longitudinal axes (5a, 5b) of the drive shafts (4a, 4b) by the length of the housing (25).

Images