GB2064744A

GB2064744A - Improvements in and relating to crop drying facilities

Info

Publication number: GB2064744A
Application number: GB7941163A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-11-29
Filing date: 1979-11-29
Publication date: 1981-06-17
Also published as: GB2064744B

Abstract

A drying facility for harvested crops such as cereals comprising a building having sides 10 and 12 and a pitched roof 14, 16 the latter having a double skin and thereby creating a narrow gap between the outer surface of the roof and an inner insulating layer 18. Air is fed into the gap at one end and has to traverse through the gap along the entire length of the building before it is extracted through a manifold 22 and duct 24 into a fan unit 26 from where it is blown along central ducting 30 and feeder ducts 32 below the stored harvested material loaded into the building on either side of the central ducting 30. The invention provides a degree of pre-heating for the air which is to be circulated through the harvested material and relies on the solar radiation incident on the roof 14, 16 to heat the air in this way. The external surface of the roof is rendered radiation absorbent and thermally conductive whilst the inner skin of the roof 18 is rendered thermally insulating so as to trap the heat within the gap. <IMAGE>

Description

SPECIFICATION Improvements in and relating to crop drying facilities Field of invention This invention concerns crop drying faciiities typically used for drying out harvested cereals to reduce the moisture content of the harvested material.

Background to the invention It is known to dry harvested cereals and the like by passing dry and warmed air through the cereal using a forced draught so as to removed moisture from the harvested material and reduce the moisture content thereof. Typically such driers have incorporated either an electric heating element or some form of burner carefully shrouded from the material to be dried and operating so as to warm a draught of air blown thereover from a fan or the like.

Such apparatus has hitherto been installed in a barn or similar outbuilding on a farm and whilst it is of some use in treating harvested material shortly after the material has been harvested, the main disadvantage being the high cost of power needed to provide sufficient heat for rapid drying. It is an object of the present invention to reduce significantly the heating costs for such installations.

With the increasing tendency to store harvested cereals in bulk in special purpose buildings, it is a further object of the present invention to provide a complete facility for drying and storing harvested cereals and like crops.

The invention According to the present invention a crop drying facility comprises an enclosure within which a harvested cereal crop or the like can be stored, entrance and exit doors by which harvested grain can be supplied to the enclosure and withdrawn from the enclosure, inclined roof means covering the enclosure the roof means comprising an outer skin and an inner skin spaced therefrom to define a narrow duct through the roof, air inlet means associated with the gap between the inner and outer roof skins through which air can be drawn to thereafter permeate through the gap between the inner and outer roof skins, air exit means and duct means associated therewith for collecting air after it has passed through the gap between the two roof skins and duct means for conveying the collected air to fan means operating so as to draw air from the cavity through the said duct and further ducting for distributing the air from the fan means so as to dry the bulk material within the drying facility.

Preferably the air inlet includes means such as louvres for controlling the volume and pressure of the air entering the gap between the inner and outer roof skins.

It will be seen that in daylight air which has passed through the gap between the inner and outer skins of the roof will be warmer than air which is entering the gap and by adjusting the louvre means or other air flow control means, so the rate of flow of the air through the gap can be controlled so that just the required temperature rise can be achieved and the warmed air is available for permeating the harvested material for drying same.

Preferably the outer skin material is adapted to collect solar radiation and rise in temperature as a result of solar radiation incident thereon. Preferably the inner skin is formed from a thermally insulating material so that the heat obtained from the solar radiation incident upon the outer skin of the roof is trapped within the gap between the inner and outer skins forming the roof so that the heat is available for warming the air passing through the gap.

The outer skin of the roof may be formed from aluminium sheet material which may be painted or impregnated black, translucent or black sheets of plastics material with or without fibreglass reinforcement or corrugated steel sheet which may be coloured black.

The inner skin of the roof may be formed from insulating fibreboard, fibreglass insulation, mineral fibre particulate material, expanded polymer plastics sheeting or sheets of compressed fibres or particles having a low thermal conductivity.

Preferably a sensor is provided for determining the temperature and humidity of incoming air and another for determining the temperature and moisture content of the harvested material. Electric circuit means may be provided, responsive to the signals from one or more of the sensors for actuating means for controlling the rate of flow of air through the narrow gap between the outer and inner skins of the roof to control the temperature of the air heated within the said gap to an optimum level having regard to the function required.

An existing building may be modified so as to include the invention by fitting an inner skin (or an outer skin as the case may be) to an existing building roof using existing roof support members to define the gap between the inner skin and the outer skin or main roof.

The roof members of the existing building thus constitute spacers holding the inner and outer skins apart and at the same time supporting the added inner or outer skin. The roof members which serve as the said spacers may be formed from wood or metal or concrete.

The invention will now be described by way of example with reference to the accompanying drawings in which Fig. 1 is a perspective view partly cut-away of a crop drying facility embodying the invention and Fig. 2 is an opposite end perspective view.

A barn like building is shown in the drawing formed from side walls generally designated 10 and 1 2, a pitched roof having panels which define an outer skin 14 and 16, and spaced therefrom, on the inside of the building, an inner skin 1 8 which is shown partly cut-away and which is supported on the underside of roof supporting beams 20. The inner skin may consist of insulating fibreboard, fibre-glass insulation, mineral fibre (or particle) insulation, expanded polymer plastics insulation or compressed fibre (or particle) sheets.

At the righthand end of the building as shown in the drawing, there is a manifold generally designated 22 which is formed in the end wall of the building, which communicates with the gap between the inner skin 18 and the outer skin 14 on the one side of the roof, and between the inner skin (not shown) and the outer skin 1 6 on the other pitch of the roof. In this way air which has passed through the gap from the lefthand to the righthand end of the building as shown in the Figure will be collected in the manifold 22 and a duct 24 serves to supply the collected air to a fan unit 26 driven by a motor (not shown) contained within a housing 28 for supplying air to a central distribution duct 30 which extends the length of the building.

From the central duct 30 extend feeder ducts 32 which themselves are apertured so as to allow air to permeate through the harvested material which is loaded into the building on both sides of the central duct 30.

For clarity the harvested material is not shown in the drawing.

A control unit generally designated 34 is fed with electrical signals relating to the temperature and humidity of the incoming air determined by sensors (not shown) located at the air inlet to the gap between the inner and outer skins of the roof and signals from these sensors are supplied along signal path 36. In the same way further sensors are located within the building such as 38 and connected to the main control unit via signal paths such as 40 to sense the temperature and moisture content of the harvested material within the building.

By using appropriate material for the inner and outer skins of the roof so the gap between the two skins becomes heated and retaine heat from the solar radiation incident on the roof and this means that the air passing through the gap to the fan 26 is warmed and therefore has a greater capability of drying the crop within the building than would raw air taken in from the outside without first being pre-heated. To this end the outer skin of the roof is made thermally conductive and the outer surface is rendered receptive to solar radiation and is made preferably non-reflective so as to absorb as much radiation as possible.

The inner skins is preferably formed from thermally insulating material so as to retain the heat within the gap.

Claims

1. A crop drying facility comprising an enclosure within which a harvested cereal crop or the like can be stored, entrance and exit doors by which harvested grain can be supplied to the enclosure and withdrawn from the enclosure, inclined roof means covering the enclosure the roof means comprising an outer skin and an inner skin spaced therefrom to define a narrow duct through the roof, air inlet means associated with the gap between the inner and outer roof skins through which air can be drawn to thereafter permeate through the gap between the inner and outer roof skins, air exit means and duct means associated therewith for collecting air after it has passed through the gap between the two roof skins and duct means for conveying the collected air to fan means operating so as to draw air from the cavity through the said duct and further ducting for distributing the air from the fan means so as to dry the bulk material within the drying facility.

2. A crop drying facility as claimed in claim 1 in which the air inlet includes means for controlling the volume and pressure of the air entering the gap between the inner and outer roof skins.

3. A crop drying facility as claimed in claim 1 or 2 in which the outer skin material is adapted to collect solar radiation and rise in temperature as a result of solar radiation incident thereon.

4. A crop drying facility as claimed in Claim 1, 2 or 3 in which the inner skin is formed from a thermally insulating material so that the heat obtained from the solar radiation incident upon the outer skin of the roof is trapped within the gap between the inner and outer skins forming the roof.

5. A crop drying facility as claimed in claim 3 in which the outer skin is formed from aluminium sheet material painted or impregnated black, or translucent sheets of plastics material with or without fibreglass reinforce ment or corrugated steel sheet painted or impregnated black.

6. A crop drying facility as claimed in claim 4 in which the inner skin of the roof is formed from insulating fibreboard, fibreglass insulation, mineral fibre particulate material expanded polymer plastics sheeting or sheets of compressed fibres or particles having a low thermal conductivity.

7. A crop drying facility as claimed in any of claims 1 to 6 further comprising a sensor for determining the temperature and humidity of incoming air.

8. A crop drying facility as claimed in any of claims 1 to 7 further comprising a sensor for determining the temperature and moisture content of the harvested material.

9. A crop drying facility as claimed in claim 7 or 8 further comprising electric circuit means responsive to the signals from one or more of the sensors for actuating means for controlling the rate of flow of air through the gap between the outer and inner skins of the roof.

10. A crop drying facility constructed arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawing.