CS257212B1 - High pressure liquid chromatography preparative column heads - Google Patents

Abstract

The solution relates to the field of high-pressure chromatography. The essence of the head is that the external thread for clamping is formed on the outer surface of the head as a left-handed one, the upper part of a right-handed nut with an internal left-handed thread is screwed onto it, the lower part of which is provided with an internal right-handed thread corresponding to the external right-handed thread of a stainless steel seamless tube, a cylindrical recess is formed in the head for accommodating the filter material, the lower part of the head is expanded in a funnel-like manner for accommodating a flexible sealing ring of triangular cross-section.

Description

The present invention relates to a preparative column for high pressure liquid chromatography.

Liquid chromatography is carried out on a chromatography column, which is a tube of circular cross section filled with fine-grained material, provided with a cap at both ends, called a column head. Via a head, the column is connected by a capillary to the chromatographic apparatus.

The chromatographic columns can be made of a variety of materials, metal, plastic or glass. Metal columns are used for higher pressures and larger diameters, while glass or plastic columns are preferred for lower pressures.

Known closures - heads of metal columns use special fittings, which are threaded on a smooth tube and then tightened to this tube fixed to the partial deformation of both the outer and inner diameter of the column.

The disadvantage is that in case of insufficient tightening of the fitting or in case of a greater wall thickness of the column, the wall of the column and the fixing ring do not deform and under the consequent operating load the fitting is removed from the tube and the column opens.

Another type of heads is a closure realized by means of a screw connection. The terminal head is internally threaded and the column has external threads. In order to seal this connection even at higher pressures, it is necessary to insert a seal between the head and the column and tighten the head against the column with sufficient force.

For this purpose, the heads and columns are provided with surfaces for the use of tightening tools, wrenches. The column, which is generally made of seamless stainless steel tube, is provided with at least two flats for mounting tightening tools.

In the places where the tightening surfaces are realized, the intercircular cross-section of the column is weakened. With larger column diameters, there is an unfavorable ratio between column wall thickness and tightening pad length. The strength of the column wall must be increased by the depth of the tightening surfaces in order to satisfy the column in terms of strength and the length of the tightening surfaces. A further disadvantage of this connection is that during tightening, the compression surfaces on the column are damaged, which is usually not of sufficient length. The relatively thin wall of the column collapses and therefore the internal diameter changes - resp. cross-sectional column, which results in disruption of the column packing and its decommissioning. When closing the packed columns there is a relative rotation between the column and the head, the top layer of the column is disrupted, the packing is pushed out of the columns into the screw connection and there is a risk of seizure of this connection.

Many of these disadvantages are obviated by the head of the preparative high-pressure liquid chromatography column according to the invention, which is characterized in that the external thread for clamping is formed on the outer surface of the head body as left-handed and screwed on the upper part of the right-left nut. the lower part is provided with an internal right-hand thread corresponding to the external right-hand thread of a stainless steel seamless pipe. A cylindrical recess is provided in the head for receiving the filter material. The lower part of the head is funnel-shaped to accommodate a flexible sealing ring of triangular cross-section.

The column designed according to the present invention eliminates the drawbacks described, is mechanically strong, simpler to manufacture, and therefore unlimited in use. Its overall simplicity is used in production, filling and especially in its own use. The advantage of this solution is that during tightening, closing, the column and the heads approach each other axially with respect to each other, without rotating between the head, the filter material and the column. A further advantage of this solution is that, at low tightening forces, a perfect and repeatable sealing of the column occurs.

An exemplary embodiment of the head of a preparative high-pressure liquid chromatography column according to the invention is shown in the accompanying drawing, which is a schematic sketch of a section through the head and column. Stainless steel seamless pipe 1 is provided with an external right thread 2, terminates with an outer shoulder 3 and a bearing surface 22 It is screwed into a right-hand nut 1 with an internal right-hand thread 16, an internal left-hand thread 25 and an internal step 6. The head 7 is also made of stainless steel and is provided with an external thread of the opposite direction, i.e. left, identical external shoulder 9, a conical recess 10 for the flexible sealing ring 11, a cylindrical recess 12 for the filter material 13, an inlet 14 terminated with an opening 15 for chromatographic liquid. . The filter material 13 is provided with a groove 16 for better sealing and circumferential handling. The head 7 is terminated with a capillary connecting screw 17, a sealing cone 19, a spacing tube 20 with a longitudinal groove 21. Male right hand thread 2 stainless steel seamless pipe 1, male thread The head 7 and the right-hand female thread 7 of the left-hand nut 4 are protected against filling and contamination in case of leakage or sudden leakage of the ultraviolet medium and the filling through the groove space 23, with vent holes 24.

The right-hand nut 6 is screwed onto the filled stainless steel pipe 1, the filter material 13 is inserted with the elastic sealing ring 11 of triangular cross-section, then the column head 7 is screwed and tightened to the stop by hand. The sealing of the column can be realized without changing the flexible sealing ring 11 several times.

The present invention is preferably applicable to all high pressure liquid chromatography columns.

Claims (1)

SUBJECT OF THE INVENTION High-pressure liquid chromatography column head provided with clamping thread and bearing surface, characterized in that the external thread (8) for clamping is formed on the outer surface of the head (7) as a left-handed, onto which the upper part of the right-hand nut (4) is screwed. a female left-hand thread (25), the lower portion of which is provided with a female right-hand thread (5) corresponding to the male right-hand thread (2) of the stainless steel seamless pipe (1), a cylindrical recess (12) formed in the head (12) 1), the lower part of the head (7) is funnel-shaped to receive a flexible sealing ring (11) of triangular cross-section.