3 " 4
porated into a column and a radial mixing of the eluting around the edges thereof. It is then possible for these agent takes place in the zone between the two sieve.plates combinations to be moved axially in the column correforming each pair. In the case of two or more pairs of sponding to the changes in volume of the column filling, sieve plates, the pairs are spaced apart. The adsorption Each sieve plate generally comprises a plate 1 conagent in the column is kept out of the mixing zone or taining holes and covered with a fine metallic or synzones by the sieve plates. The eluting agent, after having thetic resin gauze or mesh 2 which is not subject to attack been mixed in the mixing zone flows uniformly through by the elution agent, the mesh being arranged on that the lower sieve plate of the pair of sieve plates into the side of the sieve plate which is adjacent to the column next separation zone of the column. filling. The openings in the plate must be of such a size Generally, the mixing which automatically takes place ^ that the elution agent can pass through them without in the zone between the two sieve plates of a pair suf- encountering too much resistance but cannot be too large fices to produce satisfactory results. However, in the case in order that the mesh 2 is not subjected to very conof really large column diameters, this automatic radial siderable mechanical stresses. Opening diameters of 2-15 mixing alone is not sufficient and, therefore, it is advan- mm., preferably of 5-6 mm., have proved to be partageous in these instances to provide, between the sieve lg ticularly useful. The strength and mesh size of the meshes plates of each pair, a device which ensures a thorough to be used depend upon the particle size of the adsorpmixing of the liquid in the zone established between the tion agent used and, therefore, can be varied considertwo sieve plates of a pair. As mixing devices for this ably. Mesh sizes of 0.02-1 mm., preferably 0.1-0.2 mm., purpose, there are suitable, for example, mechanically- have been very successfully used. However, the dimendriven stirrers, magnetic stirrers, vibrators, ultrasonic 2o sions of the perforated plates, of the openings in these devices and the like, the choice of the possible and pref- plates and of the meshes must be so chosen that the erable mixing device depending in each instance, of adsorption agent cannot pass through and that the sieve course, on the dimensions and structural material of the plates do not become blocked up. In addition, of course, column. In actual practice, one embodiment of the inven- the sieve plates as a whole must be capable of withtion in which a centering plate 3 is arranged between 25 standing, without bending, the pressure load of the column a pair of sieve plates 1 and 1' has proved to be particu- filling, including the pressure due to the flow-through larly expedient. This embodiment has the particular of the elution liquid.
advantage, that, with structurally simple means which The dimensions of the mixing zones according to the
do not require supervision, a thorough radial mixing is present invention as noted above do not directly depend
ensured. Two instances of constructions of such center- gg upon the inner dimensions of the column and are advan
ing plates are shown in FIGS, la and lb of the accom- tageously 1 to 5 cm. in height and are located 0.5 to 2
panying drawings. In the case of a very large column meters apart. Clearly the distance between the two sieve
diameter, it may also prove advantageous to mount a plates should be as small as possible in order to avoid
distribution head below the centering plate. unnecessary remixing, but they must be large enough to
A radial mixing can also be achieved, with or without gg ensure complete axial mixing. When using sieve plates
the use of the centering plate by utilizing an arrange- wherein the openings in the sieve plates are not parallel
ment wherein the openings in the sieve plates are not to the axis thereof but rather are positioned at an angle
parallel to the axis thereof but rather are positioned at up to some 50°, axial mixing is established in a smaller
an angle to the axis so that fluid flowing through the area and the distance between the sieve plates of each
openings tends to rotate about the axis of the sieve plate. 40 pair can be reduced.
With a suitable thickness of the sieve plate and a suf- The material used in the construction of the mesh acficient angle of the openings, by the rotation of the cording to the present invention depends on the solvent column of liquid between the two sieve plates there is and the absorption agents as used within this process. Maensured a sufficient mixing and a uniform impinging of terials such as polyvinylidene chloride, polypropylene, the liquid over the whole of the lower sieve plate. 45 nylon, Perlon, Teflon, nickel-plated wire mesh and stain
The incorporation of the sieve plates into the column less steel mesh can be used with good success, can be achieved by flanging, that is, by constructing a The material of the gasket is used according to the column from a plurality of short columns joined together present invention can be chosen from the broad range of by pairs of sieve plates of the above-described type. How- compressible materials which are not affected by the elutever, it has proved to be especially advantageous to use 50 jng agent and include, for example, rubber synthetic rubone long column unit and to insert therein one or more ber, silicon, and Teflon.
combinations each comprising a pair of sieve plates and The optimum distances between any two mixing zones,
preferably also a centering plate. These combinations j.e.; the location of the mixing zones in the column is
(two sieve plates and possibly a centering plate) can comparatively independent of the column diameter and
be moved axially into any desired position and are held 55 advantageously is chosen so that the mixing zones are
in place by various means as, for example, by an annular located at distances one from the other at distances of
gasket 4. Furthermore, these combinations can be pro- o.5 to 2 meters and preferably at distances of 0.75 to 1.2
vided with one or two annular distance pieces or spacers meters. The dimensions, i.e., height of the mixing zones is
5, dimensioned so that their outer diameter is somewhat also aimost completely independent of the column diame
less than the inner diameter of the column, in order to 6Q ter and advantageously amounts to from 1 to 5 cm. and
combine these combinations to form a single unit. This preferably from 2 to 3 cm. in height. The installation,
preferred constructional form of the device according to ;e; the fastening of the individual mixing zones into
the present invention can be inserted at any desired posi- columns having fairly large diameters is preferably car
tion in the column. Consequently, a column which has ried out by screwing the mixing elements to the wall
already been set up, m this, manner, can be adapted 6_ througn narrow consoles fastened to the inner walls of
quickly and easily to the prevailing conditions resulting, a coiumn. In order t0 enable the installation and removal
for example, from the nature of the adsorption agent, of the m;xjng eiernents from the column, the elements
the flow-through rate and the like, so that it is always are formed with corresponding grooves which, if desired,
possible to work under optimum conditions. In the case can be sealed prior to operation of a column. The seal
of the use of column fillings which swell considerably 70 mg 0f the individual zones to the column wall is prefer
and, depending on the degree of charging, undergo con- ably carried out by constructing the mixing elements
siderable changes in volume (e.g., ion exchangers), it with conically tapering walls. Sealing rings are then in
is recommended only to draw on the compressible annular stalled and held through the conically tapering walls of
gasket to such an extent that adsorption agent and elution the mixing zone section in close abutting contact with the
liquid cannot flow past the sieve plate combinations 75 abutting wall.
