A flow generation device

Abstract

A flow generation device (100; 200; 300; 400; 500) for flowing liquid and biomass (101), the flow generation device comprises a first rotor (103; 303; 403; 503) having an axis of rotation (A) and an outer radius (R), a housing (104; 304; 404; 504) encompassing the first rotor and forming a closed liquid volume with an inlet (105) and an outlet (106) for liquid and biomass, the first rotor adapted to provide a circulating motive liquid flow (107; 507) within the housing, a liquid and biomass channel (109; 209; 309; 409; 509) separate from the housing and extending within the housing from the inlet to the outlet, the liquid and biomass channel comprising openings (111; 211; 511) for the circulating motive liquid flow to flow the liquid and biomass inside the liquid and biomass channel from the inlet to the outlet.

Description

A FLOW GENERATION DEVICEField of the invention

[0001] The invention relates to a flow generation device for gently and efficiently transporting liquid and biomass, preferably fish.Background of the invention

[0002] In aquaculture, the need to transport biomass, such as fish, from one destination, such as a fish pen or tank, to another, such as a transportation vessel, fish pen or tank, often requires an arrangement of pumps and tubes to forcefully move the biomass. Such conveyances occur multiple times during the lifespan for farmed fish; from early stages when they are moved from land-based hatching facilities to sea based cages or pens, or at later stages when they are transported from fish pens to a well boat or from a well boat to a processing facility. Further handling and transportation may be required as methods for removing parasites or treatment against deceased may be performed on specialized treatments vessels.

[0003] Each transportation stage puts the live fish at risk of being harmed, and great care and resources are put into performing these tasks as gently and harm free as possible. In addition to causing harm to living organism, harming the fish may cause financial losses and regulatory problems for the aquaculture farmer.

[0004] The handling of the fish greatly impacts the quality of the fish and economical gain for the farmer. Various systems and devices have therefor been developed to transport live fish as efficient and gently as possible. Common pumps and arrangements used for transporting live fish are jet type pumps or rotary ejector pumps where a fast-moving fluid is introduced through one or a plurality of nozzles into a larger volume stream causing the larger body of water to move which creates a suction inlet and a discharge outlet.

[0005] Commonly known systems and methods have the downside of suddenly introducing a fluid in a stream over a small area, causing a sudden change in pressure over a short distance. In an ejector type pump, there will be a sudden and large increase in both speed and pressure downstream of the introduction nozzle, while for a rim driven impeller pump there will be a sudden decrease in pressure upstream of the impeller and a sudden increase in pressure downstream of the impeller. Suddenincreases or decreases in pressure occurs where fluid is removed or introduced into the pump stream. Such abrupt changes in fluid velocity and pressure can cause great harm to the soft tissue and organs of the biomass and cause the live fish to be violently forced into tube walls, sharp edges or each other.

[0006] It is therefore an aim of the present invention to overcome the shortcomings of the prior art and to provide an alternative to the prior art. It is a further aim of the present invention to provide a system for transporting fluid and biomass in an evenly and gentle manner without sudden pressure increases. To achieve this objective a flow generation device according to the independent claim is provided.Summary of the invention

[0007] The invention is set forth and characterized in the main claim, while the dependent claims describe other characteristics of the invention.

[0008] In a preferred embodiment, a flow generation device for flowing liquid and biomass comprises a first rotor having an axis of rotation and an outer radius, and a housing encompassing the first rotor and forming a closed liquid volume with an inlet and an outlet for liquid and biomass. The first rotor is adapted to provide a circulating motive liquid flow within the housing. The flow generation device further comprises a liquid and biomass channel separate from the housing and extending within the housing from the inlet to the outlet. The liquid and biomass channel comprises openings for the circulating motive liquid flow to flow the liquid and biomass inside the liquid and biomass channel from the inlet to the outlet.

[0009] In another embodiment, at least a portion of the liquid and biomass channel is arranged within the outer radius of the first rotor from the axis of rotation.

[0010] In yet another embodiment, the first rotor is disc shaped.

[0011] In yet another embodiment, the housing is cylindrical and the motive liquid flow is circular.

[0012] In yet another embodiment, at least a portion of the liquid and biomass channel comprises a four-sided cross section, and the openings are provided at least at sides of the liquid and biomass channel facing the first rotor.

[0013] In yet another embodiment, at least a portion of the liquid and biomass channel comprises a circular cross section, and the openings are provided around the periphery of the liquid and biomass channel.

[0014] In yet another embodiment, the liquid and biomass channel comprises a bend having a radius concentric with the axis of rotation.

[0015] In yet another embodiment, the inlet and outlet are provided at the same longitudinal position along the axis of rotation.

[0016] In yet another embodiment, the flow generation device comprises a second rotor being encompassed by the housing, the second rotor having an axis of rotation coincident with the first rotor and the liquid and biomass channel being provided between the first and second rotors in a direction along the axis of rotation.

[0017] In yet another embodiment, the second rotor is disc shaped.

[0018] In yet another embodiment, the liquid and biomass channel is provided adjacent the first and second rotors and provided with openings facing the first and second rotors to maximize the motive liquid flow within the housing to the liquid and biomass channel.

[0019] In yet another embodiment, the liquid and biomass channel comprises a bend, and the first rotor at an outer and inner radius extends a distance in the direction of the axis of rotation to partially encompass the bend.

[0020] In yet another embodiment, the first rotor comprises a top portion, an intermediate portion and a bottom portion, wherein the top and bottom portions have an outer radius greater than the outer radius of the intermediate portion.

[0021] In yet another embodiment, the liquid and biomass channel comprises a helix shaped portion.

[0022] In yet another embodiment, the housing comprises a straight wall portion extending in a radial direction of the first rotor and the liquid and biomass channel comprises a straight channel portion adjacent the straight wall portion, the straight channel portion comprising openings.Brief description of the figures

[0023] These and other characteristics of the invention will become clear from the following description of a preferential form of embodiment, given as a non-restrictive example, with reference to the attached schematic drawings.Figure la shows a perspective view of a first embodiment of the flow generation device.Figure lb shows a top view of the first embodiment of the flow generation device. Figure 2 shows a perspective view of a second embodiment of the flow generation device.Figure 3 shows a perspective view of a third embodiment of the flow generation device.Figure 4 shows a perspective view of a fourth embodiment of the flow generation device.Figure 5 shows a perspective view of a fifth embodiment of the flow generation device.Detailed description of the invention

[0024] The following description will use terms such as "horizontal", "vertical", "lateral", "back and forth", "up and down", "upper", "lower", "inner", "outer", "forward", "rear", etc. These terms generally refer to the views and orientations as shown in the drawings and that are associated with a normal use of the invention. The terms are used for the reader's convenience only and shall not be limiting. Like numerals on different drawings describe the same feature.

[0025] Referring initially to figure la and lb, a first embodiment of a flow generation device 100 is shown. The flow generation device 100 is configured for flowing and accelerating a flow of liquid and biomass 101. The liquid is preferably water or salt water, and the biomass is preferably fish 102, but may also comprise other organisms or substances. The flow generation device 100 comprises a first rotor 103. The first rotor 103 has an axis of rotation A and an outer radius R, as indicated in figure la and lb, respectively. The first rotor 103 is in the first embodiment disc shaped, but may as such have several configurations, as will be described with reference to other embodiments.

[0026] The flow generation device 100 comprises a housing 104. The housing 104 encompasses the first rotor 103 and forms a closed liquid volume surrounding the first rotor 103. In the illustrated embodiment, the housing 104 is cylindrical. Thisallows a disc shaped first rotor 103 to be positioned at the very top or very bottom inside the housing 104. The first rotor 103 is driven by rotating means as known in the art of powering rotors. The rotating means may preferably be provided outside the housing 104, but may alternatively also be provided inside, and preferably in the center, of the housing 104. The housing 104 is preferential cylindrical, but need not be. Other housing configurations may be associated with more friction and a less effective rotating flow, and thus a less effective design.

[0027] The housing 104 comprises an inlet 105 and an outlet 106 for liquid and biomass 101. The inlet 105 may be configured for connection with a transport hose, a separate channel or connection to tanks, fish pens, etc. The outlet 106 is also configured for connection with a transport hose, a separate channel or connection to tanks, fish pens, etc. The inlet 105 and outlet 106 may be integrated elements of the housing 104. During operation, the housing 104 is filled with liquid, and the inlet 105 and outlet 106 is connected to further channels or reservoirs comprising liquid. As the first rotor 103 rotates, it generates a circulating motive liquid flow 107 within the housing 104. As the housing 104 may encompass a large volume, the motive liquid flow 107 inside the housing 104 may have high kinetic energy. A cylindrical housing 104 accommodates a large volume, and thus provides a motive liquid flow 107 of high kinetic energy. The motive liquid flow 107 flows in the direction of the rotating first rotor 103, around the axis of rotation A. The flow of the motive liquid flow 107 is greater towards the housing 104 at the outer radius R of the first rotor 103, because the speed of the rotor 103 is greater at the outer radius R.

[0028] The flow generation device 100 may also comprise a second rotor 108. The second rotor 108 is in the first embodiment also disc shaped, and may be provided inside the housing 104 on the opposite side of the first rotor 103. That is, if the first rotor 103 is provided at the top inside the housing 104, the second rotor 108 may be provided at the bottom inside the housing 104, as shown in the illustrated embodiment. The second rotor 108 has an axis of rotation coincident with the axis of rotation A of the first rotor 103, and rotates in the same direction as the first rotor 103. The second rotor 108 may increase the efficiency of the flow generation device 100, and provide a more homogenous motive liquid flow 107 inside the housing 104, further generating more kinetic energy. Preferably, the second rotor 108 is similar to the first rotor 103. Alternatively, the first and second rotors 103,108 may form one rotor with an upper and lower portion, connected at an intermediate portion. The intermediate portion may extend from the upper rotor part to the lower rotor part along the axis of rotation A. In this configuration, the first rotor 103 comprises a topportion and a bottom portion having an outer radius R greater than an outer radius of the intermediate portion. Such a configuration is described further with reference to the fourth embodiment.

[0029] The first rotor 103 and / or the second rotor 108 may be shaped such that they are symmetrical about a plane through the axis of rotation A. Because of such a non- directional design, the first and second rotors 103,108 are configured for rotation in both directions about the axis of rotation A, with equal flow-generation capabilities. The flow generation device 100 may therefore be reversible and may operate such that the inlet 105 may also act as an outlet for a flow of liquid and biomass 101, and the outlet 105 may also act as an inlet. This aspect of the invention is true for all the embodiments.

[0030] The flow generation device 100 comprises a liquid and biomass channel 109. The liquid and biomass channel 109 extends within the housing 104, and is separate from the housing 104. The liquid and biomass channel 109 is thus encompassed with liquid along the length of the liquid and biomass channel 109, inside the housing 104. The liquid and biomass channel 109 is connected to and extends from the inlet 105 to the outlet 106. In the first embodiment, the liquid and biomass channel 109 extends from the inlet 105 and comprises a bend 110 with a radius concentric with the axis of rotation A of the first rotor 103. The bend 110 of the first embodiment has an angle of 180 degrees, and the outlet 106 is thus provided with a flow direction of the liquid and biomass 101 directly opposite the flow direction of the liquid and biomass 101 at the inlet 105. The liquid and biomass channel 109 may as such comprise a bend 110 of any angle, and may not even comprise a bend at all, as will be described later with reference to the fifth embodiment. The bend 110 may preferably have an angle between 90 and 180 degrees to exploit the motive liquid flow 107 and maintain a compact design of the flow generation device 100. If the bend 110 is between approximately 0 to 200 degrees, the inlet 105 and outlet 106 may be provided at the same longitudinal position along the axis of rotation A, providing a compact design.

[0031] If the flow generation device 100 comprises a first and a second rotor 103,108, the liquid and biomass channel 109 is preferably provided between the first and second rotors 103,108 in a direction along the axis of rotation A. The liquid and biomass channel 109 may have a circular or angulated cross section. Preferably, the liquid and biomass channel 109 comprises a four-sided cross section, such as a rectangular or square cross section. If the liquid and biomass channel 109 comprises a four-sided cross section, it may preferably be positioned in close proximity to thefirst rotor 103 and / or the second rotor 108. The closer the liquid and biomass channel 109 is arranged to the first rotor 103 and / or the second rotor 108, the lower the speed of the first and second rotor 103,108 can be, in order to achieve the same flow through the liquid and biomass channel 109.

[0032] The liquid and biomass channel 109 comprises openings 111. The openings 111 allow the motive liquid flow 107 inside the housing 104 to enter the liquid and biomass channel 109, and also allow liquid to escape the liquid and biomass channel 109 to enter the volume of the housing 104. The motive liquid flow 107 inside the housing 104 thus accelerates and flows the liquid and biomass 101 in the liquid and biomass channel 109. The openings 111 are adapted to the size of the biomass or fish 102, such that liquid may be flowed efficiently through the openings 111, but the biomass or fish 102 may not. As the outside of the liquid and biomass channel 109 is affected by the motive liquid flow 107, and the volume of the housing 104 may be large compared to the volume of the liquid and biomass channel 109, the kinetic energy of the motive liquid flow 107 accommodates a strong but gentle flow of the liquid and biomass 101 inside the liquid and biomass channel 109.

[0033] The liquid and biomass channel 109 is preferably provided with a plurality of openings 111. The openings 111 may be perforations in the liquid and biomass channel 109, a netting, or similar structure allowing liquid to pass, but not biomass of a certain size. The more openings 111 provided on the liquid and biomass channel 109, and the larger the size of the openings 111, the more the motive liquid flow 107 affects the flow of liquid and biomass 101 in the liquid and biomass channel 109. The larger the area of the openings 111, the more even the flow of the liquid and biomass 101, and the less the fish 102 in the liquid and biomass channel 109 is impacted.

[0034] The liquid and biomass channel 109 preferably has a diameter or width which is smaller than the radius R of the first rotor 103. There is as such a volume of liquid both on the inside and outside of the liquid and biomass channel 109, relative to a radial direction of the axis of rotation A of the first rotor 103. Further, the liquid and biomass channel 109 is preferably positioned at an outer radius R of the rotor 103. That is, the liquid and biomass channel 109 is preferably positioned adjacent the outer sidewalls of the housing 104, where the kinetic energy of the motive liquid flow 107 is greater. In the first embodiment, the liquid and biomass channel 109 has a rectangular cross section and is sandwiched in between the first and second rotors 103,108, leaving just enough space for the first and second rotors 103,108 to rotate without interfering with the liquid and biomass channel 109. This configurationrenders a highly effective flow generation device 100. Figure la shows the first and second rotors 103,108 spaced somewhat apart from the liquid and biomass channel 109 for illustration purposes.

[0035] The openings 111 may be provided at least at a portion 112 facing the first rotor 103. If the flow generation device 100 comprises a first and a second rotor 103,108, the openings 111 are preferably provided on the liquid and biomass channel 109 at least at portions facing the first and second rotors 103,108. If the liquid and biomass channel 109 comprises a four-sided cross section, these portions may be the top and / or bottom surfaces. The liquid and biomass channel 109 is thus affected by the motive liquid flow 107 from two opposite sides, allowing a strong and gentle flow of the liquid and biomass 101 in the liquid and biomass channel 109.

[0036] If the liquid and biomass channel 109 comprises a circular cross section, the openings 111 may be provided around the periphery of the liquid and biomass channel 109. The openings 111 may also be provided around the periphery of the liquid and biomass channel 109 if the liquid and biomass channel 109 has an angulated cross section. Because the liquid and biomass channel 109 is separate from the housing 104, the openings 111 can be provided all around the periphery of the liquid and biomass channel 109, allowing the circulating motive liquid flow 107 to affect the liquid and biomass 101 in the liquid and biomass channel 109 across a large area.

[0037] The first rotor 103 and second rotor 108 need not extend in a radial direction from the axis of rotation A beyond the liquid and biomass channel 109. However, the liquid and biomass channel 109 is preferably arranged in the housing 104 such that at least a portion of the liquid and biomass channel 109 is arranged within the outer radius R of the rotor 103 from the axis of rotation A. A liquid and biomass channel 109 arranged close to the first and second rotors 103,108, and arranged at an outer radius R of the first and second rotors 103,108 may be more affected by the motive liquid flow 107, and may thus be more effective. As such, liquid and biomass 101 is flowed into the flow generation device 100 at the inlet 105, gently flowed or accelerated through the liquid and biomass channel 109 of the flow generation device 100 and exited at the outlet 106.

[0038] In the following, alternative embodiments of the flow generation device are shown and described. Features of the embodiments similar to that of the firstembodiment are not described further, but features and characteristics different from the first embodiment are pointed out and described.

[0039] Referring now to figure 2, a second embodiment of a flow generation device 200 is shown. The flow generation device 200 of the second embodiment comprises a liquid and biomass channel 209 with a circular cross section. The liquid and biomass channel 209 comprises openings 211 provided around the circumference of the liquid and biomass channel 209. The circular cross section of the flow generation device 200 allows the openings 211 to be evenly distributed along the circumference of the liquid and biomass channel 209, providing a gentle and homogenous flow of liquid and biomass 101 through the liquid and biomass channel 209.

[0040] Referring now to figure 3, a third embodiment of a flow generation device 300 is shown. The flow generation device 300 of the third embodiment comprises a first rotor 303 having an axis of rotation A. The first rotor 303 extends a distance in the direction of the axis of rotation A at an outer and inner radius R of the first rotor 303. The first rotor 303 thus comprises an annular cavity 313, such as a recess extending around the axis of rotation A. The annular cavity 313 may be semi-circular in a cross section, as in the illustrated embodiment. To fit this annular cavity 313, the liquid and biomass channel 309 may correspondingly comprise a circular cross section. The liquid and biomass channel 309 may correspond to the liquid and biomass channel 309 of the second embodiment, but may be angled inside the housing 304 such that an upper portion of the liquid and biomass channel 309 is partly encompassed by the annular cavity 313. The liquid and biomass channel 309 must comprise a bend 310 to fit into the annular cavity 313, and the angle of the bend 310 may preferably be at least 90 degrees. Preferably, the angle of the bend 310 is between 90 and 180 degrees, to allow the bend 310 of the liquid and biomass channel 309 to be adjacent the annular cavity 313 as much as possible. The liquid and biomass channel 309 may also be shaped such that a portion of the liquid and biomass channel 309 extends within the annular cavity 313 around the axis of rotation A. The liquid and biomass channel 309 of the third embodiment may alternatively comprise a four-sided or other angulated cross -section.

[0041] Referring now to figure 4, a fourth embodiment of a flow generation device 400 is shown. The flow generation device 400 of the fourth embodiment comprises a liquid and biomass channel 409 comprising a helix shaped-portion. In the illustrated embodiment, the liquid and biomass channel 409 turns 360 degrees around the axis of rotation A of the first rotor 403. Further, the first rotor 403 comprises a top portion414, an intermediate portion 415 and a bottom portion 416. The intermediate portion 415 may extend between the top portion 414 and the bottom portion 416. The top and bottom portions 414,416 may preferably comprise an outer radius R greater than the outer radius of the intermediate portion 415. Alternatively, the top portion 414 and bottom portion 416 may be two separate rotors, e.g. powered from the top and the bottom of the housing 404. The intermediate portion 415 may as such be split in two portions. The embodiments of the first rotor 403 related to the fourth embodiment may also be applicable to the first rotor of the first and second embodiment. As the helix-shaped portion of the liquid and biomass channel 409 twists around the first rotor 403, the liquid and biomass channel 409 is exposed to a large area of the first rotor 403.

[0042] Referring now to figure 5, a fifth embodiment of a flow generation device 500 is shown. The flow generation device 500 of the fifth embodiment comprises a housing 504 comprising a straight wall portion 517. The straight wall portion 517 extends in a radial direction of the first rotor 503. A straight wall portion 517 is preferably provided on opposite sides of the housing 504. The housing 504, as seen in the direction of the axis of revolution A of the first rotor 503, therefore has the shape of an oblong, oval circle. In the fifth embodiment, the liquid and biomass channel 509 comprises a straight channel portion 518. The straight channel portion 518 is provided in the housing 504 adjacent the straight wall portion 517. A normal to the straight wall portion 517 thus intersects the straight channel portion 518. The straight channel portion 518 comprises openings 511. In the illustrated embodiment, the liquid and biomass channel 509 has an angulated cross section, more particularly an octagonal cross-section.

[0043] The first rotor 503 is preferably provided in the housing 504 adjacent the straight wall portion 517. The first rotor 503 may comprise a disc shaped rotor as described with reference to the first embodiment. Alternatively, the first rotor 503 may comprise a top portion, an intermediate portion and a bottom portion as described with reference to the fourth embodiment. Alternatively, the flow generation device 500 may comprise a second rotor as described with reference to the first embodiment. The first rotor 503 generates a circulating motive liquid flow 507 within the housing 504. Because the housing 504 comprises the straight wall portion 517, the motive liquid flow 507 along the straight wall portion 517 is linear, and the flow of liquid and biomass 101 inside the straight channel portion 518 is also forced in a linear direction.

[0044] Having described preferred embodiments of the invention it will be apparent to those skilled in the art that other embodiments incorporating the concept may be used. These and other examples of the invention illustrated above are intended by way of example only and the actual scope of the invention is to be determined from the following claims.

Claims

Claims1. A flow generation device (100; 200; 300; 400; 500) for flowing liquid and biomass (101)7the flow generation device (100; 200; 300; 400; 500) comprises; a first rotor (103; 303; 403; 503) having an axis of rotation (A) and an outer radius (R); a housing (104; 304; 404; 504) encompassing the first rotor (103; 303; 403; 503) and forming a closed liquid volume with an inlet (105) and an outlet (106) for liquid and biomass (101); the first rotor (103; 303; 403; 503) adapted to provide a circulating motive liquid flow (107; 507) within the housing (104; 304; 404; 504); a liquid and biomass channel (109; 209; 309; 409; 509) separate from the housing (104; 304; 404; 504) and extending within the housing (104; 304; 404; 504) from the inlet (105) to the outlet (106); the liquid and biomass channel (109; 209; 309; 409; 509) comprising openings (111; 211; 511) for the circulating motive liquid flow (107; 507) to flow the liquid and biomass (101) inside the liquid and biomass channel (109; 209; 309; 409; 509) from the inlet (105) to the outlet (106).

2. The flow generation device (100; 200; 300; 400; 500) according to claim 1, wherein at least a portion of the liquid and biomass channel (109; 209; 309; 409; 509) is arranged within the outer radius (R) of the first rotor (103; 303; 403; 503) from the axis of rotation (A).

3. The flow generation device (100; 200; 400; 500) according to claim 1 or 2, wherein the first rotor (103; 503) is disc shaped.

4. The flow generation device (100; 200; 300; 400) according to any one of the previous claims, wherein the housing (104; 304; 404) is cylindrical and the motive liquid flow (107) is circular.

5. The flow generation device (100; 500) according to any one of the previous claims, wherein at least a portion of the liquid and biomass channel (109) comprises a four-sided cross section, and the openings (111) are provided at least at sides of the liquid and biomass channel (109) facing the first rotor (103).

6. The flow generation device (200; 300; 400) according to any one of the previous claims 1-4, wherein at least a portion of the liquid and biomass channel (209; 309; 409) comprises a circular cross section, and the openings (211) are provided around the periphery of the liquid and biomass channel (209; 309; 409).

7. The flow generation device (100; 200; 300; 400) according to any one of the previous claims, wherein the liquid and biomass channel (109; 209; 309; 409) comprises a bend (110; 310) having a radius concentric with the axis of rotation (A).

8. The flow generation device (100; 200; 300; 500) according to any one of the previous claims, wherein the inlet (105) and outlet (106) are provided at the same longitudinal position along the axis of rotation (A).

9. The flow generation device (100; 200; 400; 500) according to any one of the previous claims, wherein the flow generation device (100; 200; 400; 500) comprises a second rotor (108) being encompassed by the housing (104; 404; 504), the second rotor (108) having an axis of rotation (A) coincident with the first rotor (103; 403; 503) and the liquid and biomass channel (109; 209; 409; 509) being provided between the first and second rotors (103; 403; 503, 108) in a direction along the axis of rotation (A).

10. The flow generation device (100; 200) according to claim 9, wherein the second rotor (108) is disc shaped.

11. The flow generation device (100; 200; 400; 500) according to claim 9 or 10, wherein the liquid and biomass channel (109; 209; 409; 509) is provided adjacent the first and second rotors (103; 403; 503, 108) and provided with openings (111) facing the first and second rotors (103; 403; 503, 108) to maximize the motive liquid flow (107) within the housing (104; 404; 504) to the liquid and biomass channel (109; 209; 409; 509).

12. The flow generation device (300) according to any one of the claims 1-8, wherein the liquid and biomass channel (309) comprises a bend (310), and the first rotor (303) at an outer and inner radius (R) extends a distance in the direction of the axis of rotation (A) to partially encompass the bend (310).

13. The flow generation device (100; 200; 400; 500) according to any one of the claims 1-8, wherein the first rotor (103; 403; 503) comprises a top portion (414), an intermediate portion (415) and a bottom portion (416), wherein the top and bottom portions (414, 416) have an outer radius (R) greater than the outer radius of the intermediate portion (415).

14. The flow generation device (400) according to claim 13, wherein the liquid and biomass channel (409) comprises a helix shaped portion.

15. The flow generation device (500) according to any one of the previous claims, wherein the housing (504) comprises a straight wall portion (517) extending ina radial direction of the first rotor (503) and the liquid and biomass channel (509) comprises a straight channel portion (518) adjacent the straight wall portion (517), the straight channel portion (518) comprising openings (511).

Images