|Small Scale Processing of Oilfruits and Oilseeds (GTZ, 1989, 100 p.)|
|5. Selected Equipment|
|5.1 Hand-operated equipment|
ENDA, Dakar, Senegal
ENDA promotes the use of a locally manufactured press. This press is used to reprocess the fibre that remains after the traditional process to obtain the residual oil. In this way the oil recovery is improved by 40 %.
The same result can be obtained by using this press for the semi-traditional process (as described in 2.2.1). In this case the fibre is steam-heated before pressing. As the maximum attainable pressure is only 8 bar, the press is not suitable for pressing mixtures of nuts and fibre. (As the aura variety of the Casamance has a very low pulp-to-nut ratio, it is worthwhile applying the KIT process (see 2.2.1). This improves the traditional oil recovery by another 40 %, making the overall oil yield about 80 % of the oil originally present.
The ENDA press consists of a frame built from locally available materials such as wood, iron channel and strip, and equipped with a nut and spindle. In this frame a perforated cage is placed in a container, fitted with an outlet tube, as oil receiver. The press is to be manufactured by the local blacksmith. The spindle is supplied to him by others but the nut is cast from bronze by the blacksmith himself.
Figure 25: Oil Press, as disseminated by ENDA.
Source: ENDA, 1981, after Thierno Diedhiou
The cage content is 19 litres (1). This content is such, that all the fibres of a day's production can be reprocessed in less than an hour in a few pressings.
The involvement of the local blacksmiths has many positive aspects, e.g. ready availability of spare parts and repair service close at hand. The price of the press is F CFA 30 000 (20 000 for materials and 10 000 for the work). The costs of maintenance and repair are also estimated at F CFA 30.000 per year. This includes renewing of the nut, which is subject to wear and needs to be replaced every season.
To improve upon the quality of the press ENDA is designing a reinforced version. Also auxiliary equipment, such as sterilization and heating units, are being designed. A palmnut-cracker, to obtain the palmkernels, is under development as well.
TCC, Kumasi, Ghana
For the pressing of nuts and fibre, TCC developed a sturdy press to be manufactured by local craftsmen from locally available materials. Manufacturing takes place under the guidance of the Suame ITTU, Kumasi.
Figure 26: TCC Press.
Source: GRET, after Ph. Langley, 1984, p. 22
The TCC Press consists of a table, with a few perforations, 50 cm high. A 60 cm long spindle, welded on a bottom press plate is mounted in the centre of the table. A press cage (about 30 cm diameter and 30 cm high) made from 4 mm thick cylindrical waterpipe and consisting of two halves, is placed on the table around the bottom press plate and with the spindle in the centre. The two halves are hinged at one side and locked with a pin at the other, to allow for easy opening of the cage and removal of the pressed mass. Around the spindle, a top press plate is placed, which is fixed to a threaded compression tube. On the tube a turnbar is welded. The mass is compressed in the cage between the two press plates by turning the turnbar. The turnbar can be equipped with extension tubes to enable women processors to exert enough pressure. The oil is collected below the table and the pressed mass at the side. In 1985 the price of the press amounted to C (Cedis) 29 300 (US $ 560).
The advantages of the TCC press are:
- its sturdiness
- its relatively light construction
- the possibility to exert a maximum pressure of 40 bar on the mass to be pressed, making the press suitable to press mixtures of nuts and fibre.
However the construction of the press, with the spindle in the centre, makes the removal of the press cake difficult and the press unsuitable for the pressing of oil seeds.
Additional equipment, developed by TCC and manufactured under the guidance of the Suame ITTU are:
- a cooking kettle for steaming of loose fruit
- a clarification kettle of the same size as the cooking kettle.
Processing capacity and oil recovery depend on rawmaterial. The performance of a complete TCC unit, which includes a motorized pounder (see Chapter 5.2.1) is given in Chapter 4.3.
UNATA, Ramsel, Belgium
UNATA manufactures a sturdy press, developed in cooperation with KIT. The press UNATA 4202 consists of a frame of channel iron in which a cast iron nut is mounted at the top and a flat oil receiver/ filling table at the bottom. The press should be mounted on a concrete foundation. A small frame, holding the bolts to fix the press, should be embedded in the concrete.
In the cast iron nut, a steel spindle turns, equipped with a top press plate. A perforated cage (contents 171) is filled on the table and placed in the centre of the press just below the top press plate. Pressure can be exerted on the top press plate by rotating the spindle with turnbars that can also be extended with additional bars. The oil flows on the table and is collected at both sides of the table. The press is particularly suitable to press mixtures of nuts and fibre.
The advantages of this press are:
- its sturdiness
- the easy way of emending the turnbars to make it possible to exert a maximum pressure of 40 bar
- the easy way the press cage can be removed, so that pressing can be continued with a second one
- its suitability for pressing oil seeds (with a slightly adapted press cage).
The only part that shows a little wear when the press is used continuously at maximum pressure, is the thrust bearing, where the spindle turns in the top press plate. Frequent greasing is required at this spot.
The price of the press ( 1987, ex factory) is BF (Belgian Francs) 30 600,-. Local manufacturing is quite possible as this press is presently being manufactured for sunflowerseed processing in Zambia.
Other equipment to be obtained from UNATA includes:
- parts for cooking and reheating drums - cooking kettles (up to
- reheating kettle.
Processing capacity and oil recovery depend on rawmaterial. The performance of a complete UNATA/KIT Unit is given in Chapters 3.3 and 4.3.
Usine de Wecker, Wecker, Luxemburg
A hand-operated vertical hydraulic press is manufactured by Usine de Wecker, referred to as type PM 50-83.
The press consists of a frame with a hydraulic ram at the bottom and a press cage hanging on one of the stands of the frame and swinging around it. The cage can be put in three positions: filling, pressing and discharge position.
In the pressing position, the cage hangs above the hydraulic press ram which is equipped with a low and a high pressure hand-operated pump. The filling capacity of the press is 501. Its weight is 660 kg.
The price (1987) amounts to DM 14 200 (f.o.b. Antwerp). For the cracking of palm nuts, for obtaining the palm kernels, a hand-operated cracker is available as well.
Processing capacity is in principle three times the UNATA press. However, to attain this capacity the auxiliary equipment, such as cooking kettles, pounder and/or reheating and clarification kettles, should have a comparable capacity. Oil recovery is dependent on the raw- material and which process is followed.
Tool Foundation, Amsterdam, Netherlands
This organization co-ordinates the manufacturing and sale of the 8 L spindle press, designed by KIT. This press is equipped with a steel spindle that turns in a castiron nut. The frame is constructed from sheet metal. The weight of this press is only 60 kg. Maximum attainable pressure is 40 kg/cm².
This press is particularly suitable for the so-called semi-traditional" process for the processing of oil palm fruit. In this process the nuts and fibre are separated in water and the fibre is subsequently reheated for pressing. This press can best be used in combination with cooking and reheating kettles made from oildrums. The price of the press is ( 1986) FL (Dutch Gulden) 1273.
Figure 28: 8 L Spindle Press, KIT/TOOL and Kettles
Its capacity is half the UNATA press. Oil recovery depends on the rawmaterial and which process is followed.