Tanning drums used in processing of skin, leather and the like, are closed rotatory drums. These rotatory drums have the main purpose of mixing the skins, water and chemicals.

In order for this mixing effect to be efficient, these drums have traditionally had in their interior a series of devices to favor this mixture.

These devices can be classified in: 1) Wooden pegs, rods or stakes. See A1 and A2 in Figure 1.

2) Shelves, paddles or tables. See A3 in Figure 1.

The sizes of these devices are variable.

The aims of these arrangements are to transform the electrical motor power into a) mechanical work for the mixing of skins, water and chemicals, and b) pumping work of the bath inside the drum, through the skins, in such a way that the dissolved chemicals react with the fiber network that forms the leather.

Additionally, it is necessary to open de skins and to prevent them from becoming tied up, knotted, rolled, or being damaged or suffering from

abrasion in the grain thereof, something that is not always achieved.

The present innovation refers to item 2).

Traditionally, the shelves, paddles or tables, are arranged longitudinally in the inner surface of the drums and they are radially placed, with heights of not more than 40 centimeters (16 inches approx.).

In 1998, a patent claiming the construction of drums with"inner bats" placed in a non-radial arrangement, which formed a certain angle with respect to the tangent in its strongpoint on the surface of the drum, and with heights of between 60 and 150 cm, was published. See B in Figure 1.

The present innovation refers to an amendment in the traditional radial shelves.

The length of the shelves is extended substantially and a additional tilted table is attached thereto in their ends forming a certain angle, or a spoon-shaped curved element. See C in Figure 1.

This additional element cant be oriented in one or in both rotation directions.

The overall height of the shelves plus the additional portion varies between 10 and 40% of the internal diameter of the drum.

The angle formed between the shelf and the additional portion (in case of a straight table), varies between 90° and 180°, in one direction or both.

The amount of radial shelves with the additional portion, can vary from 2 to 10 and it is variable for each dimension of drum and each type of

process that will be performed.

The drums with this innovation can run between 0,5 and 10 rpm in both directions.

C in Figure 1, shows the cross section of some forms this innovation can take.

This figure is merely illustrative and not limitative.

This innovation can be applied in any process where rotatory drums are used: Soakings, liming, deliming, pickling, tanning, degreasing, retanning, neutralization or de-acidification, dyeing, fat liquoring, dry milling, etc.

This innovation makes the transformation of the electric motor power into mechanical work more efficient, with the following advantages regarding traditional drums: - A substantial increase of the loading capacity of the drums.

- Less float needed for the different processes.

- Consequent advantage in the residual water treatment, because of less effluent processing.

- Possible savings in chemicals, for some processes.

- Eradication of tie ups, knotting and grain abrasion.

- Almost complete elimination of leather tearing and ripping within the drums.

With the purpose of facilitating understanding of the foregoing description, Figure 1 and the following references are attached hereto.

A) Cross section of conventional wooden pegs and the like.

B) Cross section of non-radial"inner bats"applied for as claims of the patent referred to in these specifications.

C) Cross section of the paddles of the present application