Abstract
A fluid refining device comprises at least two obstructions adapted to be facing with a front in an upstream direction towards an incoming fluid and a base edge opposite of the front, and a fluid outlet arranged at the base edge.
Claims
1. Fluid refining device, comprising at least two obstructions adapted to be facing with a front in an upstream direction towards an incoming fluid and a base edge opposite of the front, and a fluid outlet arranged at the base edge.
2. Fluid refining device according to claim 1, where the obstructions are triangularly shaped heads, and the heads are adapted to be arranged with a front vertex facing the upstream direction and the base edge is the edge of the triangular shape which is opposite of the front vertex.
3. Fluid refining device according to claim 1, where the obstructions are bell shaped.
4. Fluid refining device according to claim 1, further comprising a barrier section facing in a downstream direction, the barrier section comprising a series of barrier elements and interposed gaps, where the barrier elements have a turbine blade-like shape and the interposed gaps define barrier channels providing fluid communication between the incoming fluid and the fluid outlet.
5. Fluid refining device according to one of the previous claims, comprising pressure sensors, for example arranged at the fluid inlet and/or the fluid outlet and/or other locations along the fluid flow path for measuring the fluid pressure.
6. Fluid refining device according to any one of claims 1-4, comprising pressure control devices at the fluid inlet and/or the fluid outlet.
7. Fluid refining device according to any one of claims 1-4, comprising or being connected to a processor adapted to control the fluid pressure at the inlet and/or the outlet and/or at the locations of the obstructions.
Description
[0020] The invention will now be described in more detail, by means of example and by reference to the accompanying drawings.
[0021] FIG. 1 illustrates an example of an obstruction for use in a fluid refining device.
[0022] FIG. 2 shows examples of different shapes of obstructions.
[0023] FIG. 3 illustrates an example of an obstruction with a barrier section for use in a fluid refining device
[0024] FIG. 4 illustrates an example of a channel layout of a fluid refining device.
[0025] FIG. 5 illustrates the particle and fluid flow for an exemplary embodiment of a fluid refining device.
[0026] FIG. 1 illustrates an example of a triangular obstruction head 10 which may be used in a fluid refining device. The obstruction 10 comprises a obstruction head 11 and is adapted to be facing with a front vertex 14 in an upstream direction towards an incoming fluid and a base edge 17 opposite of the front vertex. A fluid outlet 12 is arranged at the base edge. FIG. 1a and FIG. 1b shows two embodiments with different size of the fluid outlet 12, having diameters 16, and 16′, respectively.
[0027] FIG. 2 shows examples of different shapes of obstructions. In FIG. 2a, the obstruction 20 is oval shaped (oval shaped head), while the obstruction 28 in FIG. 2b is circular. FIGS. 2c and 2d shows different sized semi-circle shaped obstructions 29. The obstructions 20, 28, 29 are adapted to be facing with a front vertex 24 in an upstream direction towards an incoming fluid and a have a base edge 27 opposite of the front vertex. A fluid outlet 22 is arranged at the base edge. The fluid outlets 22 have the same diameters 26 and the width 23 are the same for obstructions 20 and 28, while the and length 25, 25′ of the obstructions 20, 28 are different. The obstructions 29 of FIGS. 2c and 2d have different length and width, 25″, 25″′, 23′, 23″. Other shapes and sizes of obstructions are also possible, for example bell shaped, trapezoid shaped, etc.
[0028] FIG. 3 illustrates an example of an obstruction 30 with a barrier section 31 for use in a fluid refining device. The obstruction 30 with barrier section 31 is adapted to be arranged in a fluid flowing in the direction of the arrow. The barrier section 31 is adapted to be facing in a downstream direction and comprise a series of barrier elements and interposed gaps. The barrier elements may have a turbine blade-like shape and the interposed gaps define barrier channels providing fluid communication between the incoming fluid and the fluid outlet 32.
[0029] An example of a channel layout of a fluid refining device is presented in FIG. 4 and is comprised of a feed fluid inlet 40, a number of obstructions 41, filtrate outlets 42, and a concentrate outlet for collection of large particles and cells 44. The obstructions 41 are in this embodiment the type illustrated in FIG. 1 and are arranged to be facing with their front vertex in an upstream direction towards the incoming fluid and a base edge opposite of the front, and a fluid outlet arranged at the base edge.
[0030] In the following, we use the term particles as a general term that comprises all kinds of particles, including cells and other bioparticles. The channel contraction angle is shown as 45 and represents a decrease in flow cross section experienced by the flowing fluid entering at inlet 41 and exiting at outlet 44. The angle 45 can vary and will preferably be adapted to the specific use of the device. The angle may for example be adapted to the number of obstructions 41 and fluid outlets 42 arranged on the device as well as the amount of fluid flowing through the device. Fewer obstructions, and thus fewer fluid outlets means that less fluid is filtrated out before reaching the outlet 44, and thus the angle 45 should be smaller in order to maintain substantially continuous flow over the device.
[0031] FIG. 5 illustrates the principle used by the invention for separation and concentration of a fluid flowing through a fluid refining device. An incoming feed flow with cell/particles of various properties, such as size, deformability and shape, is split in a concentrate flow and a filtrate flow by means of a number of filtrate units arranged in a fluid refining device, for example as shown in FIG. 4. The filtrate units comprise obstructions 51 and filter outlets 52. The fluid flows along the path illustrated by the arrows, thus removing fluid through filtrate outlets 52 downstream of obstructions 51. These obstructions are shaped like triangles in FIG. 5, but as discussed above, they can have any shape. The combination of the suction flow through the filter outlets 52 and the incoming feed flow creates a saddle point of converging flow streamlines 56, which in FIG. 5 is positioned directly downstream of the filter outlet. Since the flow must go around the obstructions 51, a flow layer form around the obstruction. The thickness of the flow layer is determined by the fluid characteristics, such as viscosity, flow velocity etc. Particles inside this layer generally follow the flow passively and thus end up in the filtrate outlet, while particles which are larger, heavier, have different deformability etc. will not be captured by the flow layer and can be separated from the fluid and simultaneously concentrated.
[0032] There are two reasons why separation is possible. First, a particle with center-of-mass outside the flow layer gets associated with streamlines in the bulk and is therefore carried downstream with this flow. This method used for size-based separation is illustrated in FIG. 5. However, the size of the particle does not have to be larger than the extent of flow layer to achieve concentration. Instead, the inertia associated with the particle, which is resulting from the interactions with obstructions and flow field, can be utilized to generate an additional mass, called “virtual mass”, which increases the virtual size of the particle (sometimes called hydrodynamic diameter). Thus, the applicability of the geometry is not restricted to size-based separation and concentration but includes e.g. deformation-based and density based separation. Owing to the continuous dewatering of filtrate fluid through each filter outlet, particles with large virtual of physical diameters are simultaneously concentrated while they are separated from their smaller counterparts. Finally, to ensure that the velocities required for precise particle manipulation are maintained downstream, the channel continuously decreases with downstream distance, as indicated by the angle y.
