The present invention relates to an apparatus for separating a fluid into at least two components, which apparatus comprises a static part and a movable part, the static part and the movable part defining a space having a circular cross section, the movable part being formed by a wheel, the wheel being equipped to rotate around its rota¬ tion axis with the aid of drive means, the rotation axis coinciding with the axis of the space, a portion of the space being provided with bed segments comprising sorbent material for the sorption of a component present in the fluid, the bed segments being separated from each other by wall elements extending substantially axially and sealing against a part, the apparatus is further provided with suc¬ cessively a first inlet for fluid, a first outlet for a first component, a second intake for eluent and a second outlet for a second component to be discharged by employing the eluent, the inlet and the nearest outlet being spaced such that there is always at least one wall element between the inlet and the nearest outlet. Such an apparatus has been described by Barker, P.E. (Continuous Chromatographic Techniques, in Preparative Gas Chromatography, Zlatkis, A. and Pretorius, V., red., Wiley- Interscience, New York, 1971, pp. 354-357) . The bed seg¬ ments are all connected by means of a pipe provided outside the space, which pipe is provided with a controlled valve. For the supply of fluid and eluent respectively the dis¬ charge of the components separated by chromatography, the apparatus is provided with a plurality of openings (for instance 180), each of which is provided with a valve. With the aid of the valves it is possible to regulate the flow of fluid through the revolving wheel while the apparatus is in operation.

The disadvantage of the known apparatus is that it is complex and consequently expensive. A further disadvan-

tage of the known apparatus is that it is susceptible to trouble.

It is the object of the present invention to improve the known apparatus and in particular to simplify it, to make it less susceptible to trouble and to lower its costs. To this end the apparatus according to the invention is characterized in that in each wall element comprises a self-sealing valve allowing fluid moving toward the outlet to pass through, while obstructing fluid moving in the opposite direction.

In this manner the fluid respectively the eluent will not flow toward the outlet nearest the corresponding supply opening, if that outlet does not belong to the respective supply. The use of self-sealing valves in the chamber, is a simple and effective manner to make trouble- susceptible controlled valves redundant.

According to a preferred embodiment of the apparatus according to the invention, the bed segments seal against a part which is movable in respect thereto. This prevents part of the fluid or the medium for the removal of the component separated out of the fluid from the bed segment, from flowing between the portion which is not provided with bed segments and the bed seg¬ ment, whereby it would only remain in the bed segment for a short time, namely during transition from one segment to the other.

The bed segments for the separation of fluid into components preferably comprise a component-sorbing fibre material. Such a highly porous fibre material possesses numer¬ ous advantageous properties. In addition to having a low flow resistance it can also, compared with for instance granules, be retained extremely well in the bed segment.

According to an alternative embodiment, the bed seg- ments for the separation of fluid into components comprise a component-sorbing foam with an open cell structure.

If desired, such a bed segment may have a low flow resistance and in particular a simple structure so that it can easily be cut to size.

In the present application the term sorption means the separation of one or more components from a solution or homogenous mixture by means of selective absorption or retention by a solid substance (the sorbent) . The present invention will now be elucidated with reference to a non-limiting embodiment, in which

Fig. l is a schematic cross-section of the apparatus according to the invention; and Fig. 2 is an enlarged detail of Fig. l.

The apparatus according to the invention shown in Fig. 1 comprises a housing 1 having a circular chamber 2, which chamber is confined by a smooth inner wall 3 of the housing 1. The chamber 2 comprises a wheel 4 which is rotatable around a rotation axis 5. The axis of the circu¬ lar chamber 2 coincides with that of the wheel . The wheel 4 is provided with side walls (not shown) which seal against the housing 1, and the wheel 4 together with the sealing side walls and the chamber 2 confine a space 6. The space 6 comprises bed segments 7 (only one of which is shown in Fig. 1) which are separated from each other by wall elements 8 sealing against the inner wall 3 of the housing 1 (only one is shown in more detail) . Each wall element 8 is provided with one or more valves 9, such as a non-return valve. The valve 9 is self-sealing, that is to say the valve 9 will be sealed under the influence of a mechanical force, such as may be exerted by a spring, or by the pressure locally prevailing in the fluid.

The sorbent material of the bed segment 7 may be any material suitable for the purpose and may for instance take the form of granules. However, a preferred form of sorbent material is fibres. The advantage with this is that the fluid has to undergo little resistance when using the apparatus. Also, it is easy to hold fibre material together, for instance, with filter cloth. Preferably the bed segment 7 has a self-supporting structure. To prevent that sorbent material that has come loose from the bed seg¬ ment 7 disrupts the working of the valves 9, it is

possible, for instance, to provide perforated elements (not shown) between the bed segment 7 and the valve 9.

According to another favourable embodiment the bed segment 7 is a foam having an open cell structure. Since the bed material does not come loose, perforated elements are superfluous.

To guarantee the best possible separation the bed segments 7 seal against the inner wall 3 of the housing 1. This prevents fluid flowing over the sorbent material instead of through it.

In this respect it is advantageous to use a fibre material or a foam having an open cell structure, because such material will often have pliant-resilient properties ensuring a good seal between bed segment 7 and inner wall 3. It is of course necessary to ensure that there is not too much friction. Advantageously a bed segment is pro¬ vided, at least at the side facing the part movable in relation to it, with a friction-reducing means, such as filter cloth. For the elimination of (aromatic) hydrocar- bons from water, cross-linked PUR foam or silicone rubber, may, for instance, be used.

Fig. 2 shows how a wall element 8 seals against the smooth inner wall 3 of a housing 1. The side of the wall element 8 facing the inner wall 3 is provided with a groove 10. Into the groove 10 a strip of elastic material 11 is introduced which is formed, for instance, from silicone rubber or EPDM rubber. The strip 11 presses a sealing element 12 which is formed, for instance, from teflon, against the smooth inner wall 3. In the same manner the side walls (not shown) seal against the housing 1.

In order to keep the friction between the wheel 4 and the housing 1 to a minimum, care should be taken when dimensioning the apparatus to adjust the seal between the wheel 4 and the housing 1 such that the sealing force is just sufficiently great to prevent leakage. A greater force will only result in the wheel 4 requiring more energy for turning without affording any further advantages. The same holds for the dimensioning of the bed segments 7.

The apparatus is provided with a first inlet 13 for fluid to be separated into two or more components, a second inlet 16 for the supply of eluent by means of which compo¬ nent, which has been sorbed by the sorbent material of the bed segment 7, can be removed in order to regenerate the sorbent material, or, as in the case of chromatographic applications, be eluted, and with outlets 14, 15, for the first and second component respectively. Supply and dis¬ charge may, if so desired, also take place via the axis of the wheel 4. If the component is a volatile organic chemi¬ cal such as toluene or oil, it is also possible to use steam to strip the sorbent material for regeneration. Of course, the apparatus may possess still more inlets and outlets for possible additional treatment of the sorbent material, such as flushing and drying. Similarly, more inlets and outlets may be provided for fluid and eluent, thereby providing more separation runs over the circumfer¬ ence of the wheel.

According to a practical embodiment, the side walls of the apparatus constitute part of the wheel 6. Such an apparatus can easily be up-scaled in axial direction. Instead of that, it is possible to have one or both side walls static, so that they can be used for the supply and inlet. The advantage of using one or more static side walls is that an adequate seal may be achieved with somewhat less effort.

Although the present invention describes each wall element to be provided with a valve, it should be obvious that within the frame of the invention fewer wall elements may be provided with a valve as long as between an inlet and its nearest outlet at least one of the wall elements is provided with a valve. For the least possible flow resis¬ tance and a good flow tendency it is expedient if a large part of the wall element is furnished with one or more valves. Appropriate placement of the valves will result in the best possible flow profile, that is to say optimal uti¬ lization of the bed segment 7. In view of the fact that the inlets and outlets in the described embodiment are located on the same side, i.e. the circumference, it may for

instance be favourable to place the valves nearer to the rotation axis in the wall elements.

According to the invention the bed segments may be stationary and the openings rotating or vice versa, and even a combination is feasible. If the openings rotate, they are advantageously located on the side of the space near the rotation axis, because then less energy is required to carry out the rotation as, due to the surface being smaller, there is less friction.