EntrePinoys Atbp.

Significant losses and quality deterioration occur because high moisture content of freshly harvested grain is not immediately reduced to a level safe for storage. The situation becomes more difficult during rainy season when sundrying cannot be relied upon. Thus, the use of mechanical dryers such as the flatbed dryer is an option.

The flatbed dryer is of very simple design and operational features. Grains are loaded and laid out on a perforated screen flooring and dried by forcing hot air from the plenum below the grain bed. An axial fan powered by a diesel engine provides the drying air. The rice hull fed furnace provides the heat for drying. Grains are loaded and unloaded from the drying bin manually.

The dryer is found to have lower drying cost compared to existing mechanical dryers. This was mainly due to the use of rice hull as fuel, low labor requirement and low repair/maintenance cost.

Specifications

Drying bin

• Inside dimension : L=24ft, W=12ft, H=5ft
• Grain depth – 18 ft
• Holding capacity – 6.0 tons
• Made of pre-cast concrete walls not less than 1.5″ thick using class “A” concrete
• All panelized wall section construction
• Complete with perforated metal sheet flooring of 3/32″ diameter perforation and supported with steel framing
• All knockdown and bolted construction

Heat source

• Biomass furnace, direct or indirect type using rice hull/corn cobs as fuel

Blower

• Tube axial fan with 10,500 cfm capacity at 30 mm H2O SP
• Fan rpm of 1,600 rpm driven by diesel engine thru belt and pulley
• Tube-hausing diameter not more than 30′
• All steel construction made of heavy gage steel material

Engine

• Diesel-engine, 12.5 hp minimum; water cooled, single cylinder type
• Manually/hand cranked starting

Features

• Simple to construct and operate. Low initial investment cost, low maintenance and operating cost.
• Made of precast (panelized) concrete walls complete with perforated metal floor. All knockdown and bolted construction.
• Dries paddy from dripping wet to 14% moisture content in 10-12 hrs using a drying temperature of 40-45°C.
• Equipped with biomass furnace that can supply heat for 10,500 CFM.
• Has an axial fan with rated capacity of 10,500 CFM at 30 mm H2O static pressure.
• Driven by a 12.5 hp diesel engine
• With shed

How to Install

1. Prepare a leveled concrete flooring with an area more than adequate to contain the dryer and furnace 2-3 days before installation.
2. Lay-out the inner dimension of the drying bin on the concrete flooring using a marker. Use temporarily the perforated sheet to measure the dimension.
3. Assemble the concrete panels starting from the corner using the angular metal connectors and continue thereon with the other panels using appropriate flat metal connectors and bolts. Complete the assembly by installing the top metal skirt surrounding the drying bin.
4. Attach the discharge ports.
5. Place sealant at the connection between panels and at the panel base to the concrete flooring.
6. Install by bolting the steel channel floor brace along the inner side of the wall panel as well as the individual flooring bottom support.
7. Install the perforated flooring starting from one end to the other end of the drying bin.
8. Attach the canvass air duct to the bin and to the blower.
9. Locate the blower and engine support assembly and fix with the bolt that is anchored at the flooring.
10. Attach and align the engine.
11. Install the furnace. The panelized furnace design will have a separate “How To” manual.
12. Build the shed.

For more information, please contact:

The Executive Director – Bureau of Postharvest Research and Extension
CLSU Cmpd., Science City of Mufioz, Nueva Ecija
Tel. Nos. : (044) 456-0213; 456-0290; 456-0282
Fax No. : (044) 456-0110
Email: execdir@bpre.gov.ph
Web-site: www.bpre.gov.ph

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2. Techno-Guide on Biomass-Fed Furnace/Heater System for Drying Crops
3. A Simple Solar Dryer
4. Solar Dryer