On the basis of theoretical and economic considerations a medium-pressure liquid chromatography system for preparative separations was developed. The choice of stationary phases with an average particle size of about 50 μm allows a dry column packing technique and makes possible short separation times with low pressure drop. The columns can therefore be constructed of glass. Their design is very simple, the end fitting is uniform for all column sizes. A special column head ensures optimum solvent distribution which enables the use of large diameter columns without loss in performance. Measurements under analytical conditions confirmed HETP's less than 300 μm for all column sizes.