SEPARATION CHANNEL

The invention relates to a separation channel for separating a fluid flowing through into two or more components. There are known several separating methods by which a fluid can be separated into individual components. A separation principle is based on differences in mass of the molecules in a fluid. By using the force of gravity or a centrifugal force (potential), for example, it is possible to separate molecules having different mass values and thus separate a fluid into two different components.

Another separation method is based on the size of the molecules in a fluid. By causing the fluid to flow past a membrane, for example, it is possible to have molecules smaller than a specific size pass through the membrane, whilst the larger molecules are stopped by the membrane. In this way it is readily possible to separate a fluid into two individual components. However, the known separation methods make it difficult to effect a continuous separation of fluid in which the variation in molecular size or molecular mass is small.

It is an object of the invention to provide a separation channel in which a fluid can be readily separated into two or more components where this is not possible by means of the conventional separation methods.

This object can be accomplished by means of a separation channel, which separation channel comprises:

- two parallel walls, each wall having a groove structure, in which the grooves extend at an angle of more than 0° and less than 90° to the direction of flow; and

- a groove outlet, into which the grooves open for carrying off one of the two components separately.

The fluid is carried between the two parallel walls and as a result of the presence of the grooves, swirls are created. Depending on the resonance freguency of the various components in the fluid, the components will be carried along further in the main stream of the fluid, or components will create swirls in the grooves . Since the grooves do not extend either parallel to or perpendicular to the direction of flow of the fluid, the swirls in the grooves can flow out at an angle, making it possible to separate the fluid flow in the grooves from the remaining fluid flow between the two parallel walls. This is possible as long as the spacing between the walls is small in relation to the resonance freguency.

Preferably, the spacing between the two parallel walls is less than three times the groove depth of the grooves of the groove structure. This ensures that the entire fluid comes within the range of influence of the grooves, so that the entire fluid will be subject to the separating action of the grooves. In a highly preferred embodiment, said spacing is less than twice the groove depth. In another preferred embodiment, the grooves of the groove structure extend substantially parallel to each other. This is advantageous in connection with the forming of the groove structure in the walls, but according to the invention it is also possible to provide curved or conical grooves. In a highly preferred embodiment of the separation channel according to the invention, the groove structure has a breaking-wave structure. Such a wave structure has been found to effect an adeguate separation between different components of a fluid. The waves of said wave structure preferably comprise a wave crest that overhangs the groove cavity located downstream of the wave crest. The swirls formed in the groove are thus more or less protected in relation to the main fluid stream, so that the swirls can be readily carried off in the groove cavities .

The invention further comprises a blood pump comprising a separation channel according to the invention, a pump having an inlet connected to the separation channel and an outlet and at least one venturi disposed in the pump outlet, whilst the groove outlet of the separation channel is connected to the suction channel of the venturi.

Usually, the pumping blood cannot take place by means of a conventional pump, since the components of the blood may be affected by the pump's mechanical action. Only the plasma could be pumped in a conventional manner.

Using a blood pump according to the invention, it is now possible first of all to separate the blood platelets and the like from the plasma, after which only the blood plasma is pumped and the separated blood platelets and the like are supplied to the plasma again by means of the venturi. Thus, the components of the blood, which are usually damaged by a mechanical pump, are separated and carried past the pump via a bypass and added to the plasma again.

The above and further aspects of the invention will now be explained in more detail with reference to the appended drawings .

Figure 1 is a cross-sectional view of an embodiment of a separation channel according to the invention.

Figure 2 is a schematic top plan view of the separation channel according to figure 1.

Figure 3 is a detail view of a groove of the separation channel of figure 1.

Figure 4 schematically shows an embodiment of a blood pump according to the invention. Figure 5 is a detail view of a second embodiment of a groove of the separation channel of figure 1.

In figure 1 a separation channel 1 according to the invention is shown. Said separation channel 1 has two parallel

walls 2, 3, which are provided with grooves 4. The grooves 4 have a breaking-wave structure in the present cross-sectional view.

In figure 2 the separation channel 1 is shown in top plan view. The fluid F is carried into the separation channel 1, in which the grooves 4 extend at an angle to the direction of flow of the fluid F . As a result of the groove structure 4, the fluid F is separated into a first component Fl and a second component F2. Because the grooves 4 extend at an angle, the separated component F2 is carried outwards at an angle and exits the separation channel at the upper side in figure 2.

In figure 3 the groove structure of the separation channel 1 is shown in more detail. The groove structure 4 has a breaking-wave structure, in which a wave crest 5 overhangs the groove cavity 4 located downstream of said wave crest 5. When the fluid F flows between the two walls 2, 3, part of the fluid F will be caught in the groove cavity 4 and create a swirl F2 there. This separation depends on the resonance freguency of the various components. Thus it is possible, for example, to separate cold and hot air from each other, because cold air has a different resonance freguency than hot air. Thus it is also possible, for example, to separate nitrogen and oxygen from each other from common air.

In figure 4 a blood pump 6 according to the invention is shown. Said blood pump 6 has a separation channel 7, a conventional mechanical pump 8 and a venturi 9. Blood B is carried into the separation channel 7, where blood platelets Pl, among other components, are separated from the blood plasma P2. The plasma P2 is then directed into the pump 8, after which it is carried into the venturi 9 via a pipe 10. Since the plasma flow from the channel 10 flows through the main channel of the venturi 9, an underpressure is created in the suction channel 11, as a result of which the flow of blood platelets Pl is sucked along and thus mixed with the plasma flow again. In this way components

of the blood B are prevented from being damaged by the mechanical pump 8.

In figure 5 a second embodiment of a groove of the separation channel according to the invention is shown. In this embodiment, the wave shape is the reverse of the variant shown in figure 3.

Light components Fl, F2 are caught by the groove cavities, whilst the heavier component flows through centrally between the walls. The advantage of this variant is the increased heat transfer, which makes it possible to control the separation process additionally by adapting the temperature of the walls.