Abstract: The invention relates to an upwardly closed assembly and a simpler upwardly open assembly for uniformly loading one-piece carrier members, more particularly for catalysts, with a desired quantity of dispersions or solutions, the assembly being in the form of a cup receiving the bottom part of the carrier member and a distributor head for placing in sealing-tight manner on the carrier and having a perforated tray, formed with drip spouts at each outlet mouth, for distributing the applied liquid and, in the case of the upwardly-closed embodiment, including a cover and a number of pipes on the distributor head for supplying liquid, aerating and deaerating and a discharge pipe in the cup. The invention also relates to a method of operating the assembly and having features providing inter alia for movement of the distributor head relative to the carrier members in order to improve the distributor of liquid over the top surface of the carrier.