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principal investigator;

Valencia Alvero

Federación Nacional de Cafeteros de Colombia Centro Nacional de investigaciones de Café (CENICAFE) Chinchina, caldas Colombia

Figure 2a - Coffee drying carts. Each tray has a drying surface of 10 m2

Figure 2b. This indicates the operation of the drying carts.

Cette photo montre le fonctionnement des chariots de séchage pendant 1'opération.

Figure 2b. This indicates the operation of the drying carts.

Cette photo montre le fonctionnement des chariots de séchage pendant 1'opération.

Figure 4. In the photo, cement courts with moveable roofs are indicated in the right. On the left, a typical "Elba"J house for weather protection.!

Figure 3. Cement court with small roof to protect the coffee against rain.

Sur cette surface de ciment, des toits mobiles permettent de protéger les grains de café de la pluie.

Figure 4. In the photo, cement courts with moveable roofs are indicated in the right. On the left, a typical "Elba"J house for weather protection.!

Sur la photo à droite, on aperçoit des terrasses de ciment à toît mobile qui sont utilisées pour le séchage. A gauche, une maison "Elba" typique.

figure 5.' Marquee elevated on posts and covered by a polyethylene cover.

Séchoir marquise monté sur pilotis et recouvert d'un film polyethylene.

Figure 6. Marquee with cement floor and PVC roofing.

Séchoir marquise avec plancher de ciment et recouvert de PVC.

Figure 6. Marquee with cement floor and PVC roofing.

Séchoir marquise avec plancher de ciment et recouvert de PVC.

Figure 7. "Elba" house dryer The roof is put back on the house pinion for nights and rainy periods.

Le séchoir maison "Elba". On referme le toît sur le pignon de la maison pendant la nuit et durant les périodes de pluie.

Figure 7. "Elba" house dryer The roof is put back on the house pinion for nights and rainy periods.

Le séchoir maison "Elba". On referme le toît sur le pignon de la maison pendant la nuit et durant les périodes de pluie.

CASE STUDY ( B

DRYING GRAPES ON RACKS (Australia)

Overview:

Status: operation Heating mode.- natural

Type: rack-dryer Air circulation: natural airflow

In Australia, natural and sun drying of grapes on racks has been used for quite some time. Large scale drying racks are widely used in the grape growing areas of Australia and in 1972, they dried about 100,000 metric tons of fresh grapes in 8 to 14 days. One 50 meter drying unit is generally considered to provide enough rack space to dry,the fruits from three acres of vines during the drying season. (11,640 square metres)

Figure 1 - Grapes drying on racks Characteristics:

The drying rack consists of 8 to 12 galvanized wire netting tiers spaced vertically. At 3 m intervals along the racks, pairs of intermediate upright posts, imbedded in the ground, carry cross pieces that support the tiers.' The wire netting is reinforced lengthwise along both edges with fencing wire. At each end of the rack, the load is taken by two heavy posts, sloped and stayed against the strain with part of their length below ground level.

It should be noted that the rack illustrated in Figure 1 is covered by a sheet metal roof. These roofs are often very practical as they protect the raisins against rain or excessive sun, thus leading to a better quality produqt. The roof is constructed of corrugated iron sheets fixed crosswise, with equal overhang on both sides of the rack. There should be no pitch to the roof so that when wind from any direction accompanies rain, it will blow the water on the roof away from the fruit. When there is no wind, the overhang ensures that water drips away from the drying racks. Certain raisin species obtain a superior quality when shade-dried, thus hessian side curtains are often placed on the rack to provide this dondition. These curtains are to be avoided in wet climates where excessive humidities will favour mould development. Figure 2 shows the essential components of the structure of the drying racks, it should be noted that the drawing represents only part of the length of the drying rack.

Dimensions: The drying rack is usually 50 to 100 m long, 2,5 m. high and 1,5 m wide. See drawing - figure 2.

Vertical trays spacing: 25 cm wire netting (5 cm mesh): 1,2 m wide

Two-end sloped posts for taking the load: 3,5 to 4,5 m long set 1,5 m apart and imbedded 1,5 m under the ground roof: 2,4 m lengths of corrugated iron

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Legend

3 & 4 - Intermediate posts (tubular steel or angle iron)

5 - Wooden crosspiece resting on lugs supporting the tier

6 & 7 - Crosspieces welded or bolted to the end posts at their top & bottom

8 - Wooden purlins or tubular steel lengths wt'a-tw

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