GB2309291A

GB2309291A - Floor for drying crops

Info

Publication number: GB2309291A
Application number: GB9700867A
Authority: GB
Inventors: Urban George Curson
Original assignee: Burgess Ben & Co
Current assignee: Burgess Ben & Co
Priority date: 1996-01-19
Filing date: 1997-01-16
Publication date: 1997-07-23
Anticipated expiration: 2017-01-16
Also published as: GB9601117D0; GB9700867D0; GB2309291B

Description

FLOOR FOR DRYING CROPS Field of the Invention This invention relates to the field of floors for use in the drying of crops, for example grain or potatoes.

Background to the Invention Crop-drying and crop-ventilating floors are conventionally provided with a series of air ducts arranged throughout the floor and supplied with drying air via a main supply tunnel. The tunnel usually extends centrally along the floor space, for example directly beneath the apex of the crop-storage building or, alternatively, along one side of the floor space.

One such crop-drying floor is described in UK patent application number GB2 132 744A which describes a substantially flat crop-drying floor made of concrete formed with a series of substantially parallel air supply ducts of rounded shape in transverse cross-section extending parallel to the floor surface and located wholly below the same, and a series of substantially parallel air outlet slots in the floor surface extending transversely to said ducts and opening downwardly thereinto.

This arrangement suffers from a number of disadvantages. For example, the stresses on a crop-drying floor are substantial especially given the increasing size of storage buildings and depth of crops therein. Some types of crop need to be stirred during storage to ensure even drying and temperature; the moving stirrers (usually rotary) provide additional stresses on the structure of the building and floor. The circular nature of the air supply ducts in GB2 132 744A means that, at the apex of each duct, there may be only one or two inches (no more than, say, 5cm) of concrete between the air duct and the mass of crop above. This could well be insufficient to resist the stresses on the floor.

Another potential disadvantage arises if a floor is formed using the actual method specifically described and illustrated in GB2 132 744A. Inflated tubes defining the ducts are subsequently deflated and withdrawn once the concrete has set. There is thus no barrier between each duct wall and the remainder of the concrete floor, and so any imperfections or stress-induced cracks in the concrete wall or roof of a duct could lead directly to the duct's collapse and hence serious damage to the construction and operation of the crop-drying floor.

A further disadvantage of some known crop-drying floors results from their use of lift-out cleaning panels. These run the whole length of the floor to facilitate the removal of dust and other debris from the system. However, their presence means that there is, effectively, a "break" between the edge of the floor and the wall of the storage building which reduces the overall strength of the structure.

It is thus an object of the present invention to provide a crop-drying floor which alleviates the above-described problems.

Summarv of the Invention According to a first aspect of the present invention, there is provided a cropdrying floor comprising a series of air supply ducts substantially surrounded by concrete so as to form said crop-drying floor, the air supply ducts extending parallel to the floor surface and located wholly below the same, the crop-drying floor further comprising a series of air outlets in the floor surface extending transversely to said air supply ducts and opening downwardly thereinto, said air supply ducts being each of substantially rectangular, and preferably, substantially square shape in transverse cross-section.

A substantially rectangular, and in particular a substantially square, duct section is much better able to withstand the stresses on the floor during use.

It also lends itself ideally to a construction in which some or all of the ducts, instead of being merely defined in the concrete, are constructed as fabricated units in their own right and whose walls thus define a positive physical barrier between the duct, as such, and any inherent or induced imperfections in the concrete surrounding it.

Preferably, said air supply ducts are substantially parallel to one another and, ideally, said air outlets are substantially parallel to one another.

In a preferred form, therefore some at least of said air supply ducts are initially formed separately from the concrete floor as a whole, and comprise generally U-shaped lower (in use) portions having respective duct covers, each duct cover being adapted to fit closely to its associated lower portion in spaced relation thereto so as to provide a series of air outlet slots in the otherwise closed duct.

Alternatively, each of said air supply ducts comprises a generally U-shaped lower portion and an elongate duct cover adapted to fit closely to the lower portion, the duct cover having evenly spaced, transverse slots therein to provide a series of air outlet slots in the otherwise closed duct.

Advantageously, said crop-drying floor further comprises reinforcing means located within the concrete between one or more of the air supply ducts.

In a preferred form, of the feature just stated, the reinforcing means may comprise reinforcing rods located within the concrete between and substantially parallel to adjacent ones of the air supply ducts.

In a further preferred form, reinforcing means may be located within the concrete above or below and substantially perpendicular to one or more of the air supply ducts.

Ideally, the reinforcing rods at the outermost edges of the crop-drying floor extend beyond those edges and are adapted to tie-in structurally to the wall of the crop-storage building in which the crop-drying floor is situated.

Advantageously, a combination of air supply ducts of differing cross-sectional area and/or shape may be used in different parts of the same crop-drying floor.

Preferably, in use, each of said air outlets is covered by a removable strip of readily air-permeable, eg. perforated, material.

It will be understood that the invention is intended to include crop-drying floor substantially as described herein with reference to and as illustrated by any appropriate combination of the accompanying drawings.

According to a second aspect of the present invention, there is provided a method of forming a crop-drying floor comprising the steps of i) arranging a desired number of generally U-shaped elongate channel units in position, substantially parallel to one another, so as to form lower (in use) portions of eventual air supply ducts; ii) locating the required number of duct covers on top of the lower portions so as to form a series of air supply ducts, each having air outlet slots therein; ; iii) positioning a plurality of removable elongate formers transversely across the air supply ducts so as to substantially cover the air outlet slots therein, the formers being of a shape generally tapered towards the air outlet slots and preferably with means for example a generally upstanding flange provided on the duct covers at each edge of the air outlet slots - to facilitate the location of the said formers; iv) pouring settable concrete around the ducts and formers to a height at or below the plane containing the uppermost edges of the formers; v) removing said formers so as to leave behind, as the concrete sets, defined tapered air outlets opening into the air outlet slots in the ducts; and vi) covering said outlets with (preferably removable) strips of readily air-permeable material.

In a preferred form, the method further comprises the step of providing reinforcing means between one or more of the air supply ducts prior to introducing the concrete.

Ideally, the method further comprises the step of providing reinforcing means between and substantially parallel to adjacent ones of the air supply ducts, prior to the introduction of the concrete.

Advantageously, the method further comprises the step of providing reinforcing means above or below and substantially perpendicular to one or more of the air supply ducts prior to the introduction of the concrete.

In a preferred form, the method further comprises the step of structurally tieingin the reinforcing means at the outermost edges of the crop-drying floor to the nearest wall of the building in which the crop-drying floor is situated.

In a further preferred form, said formers are provided with a plurality of strengthening flanges which extend downwardly into said air outlet slots during the casting of the concrete. Ideally, the displacement between each former and each air supply duct is variable, in order to compensate for an uneven floor base, the maximum displacement being not greater than the height of the strengthening flanges and upstanding flanges on the duct covers so as to substantially prevent concrete from entering the air outlet ducts.

It will be appreciated that the invention includes within its scope a method of forming a crop-drying floor substantially as described herein with reference to and as illustrated by any appropriate combination of the accompanying drawings.

According to a third aspect of the present invention there is provided a former for use in a method of forming a crop-drying floor substantially as described above comprising an elongate member generally tapered inwardly towards its lowermost (in use) surface and having at its uppermost (in use) surface a peripheral upstanding flange.

The invention also includes within its scope a "matrix"-style assembly of parallel-spaced rectangular-cross-section air supply ducts, each of which ducts consists of a unit in its own right (ie. is not defined solely by a concrete-walled tunnel extending through the eventually set floor) and any or all of which unit is intended to put the present invention into practice.

Brief Description of the Drawings In the accompanying drawings Figures 1 to 6 show in perspective parts of a crop-drying floor embodying the invention, before concrete is introduced.

Figure 1 is a perspective view of a portion of the crop-drying floor; Figure 2 is a front perspective view of another portion of the floor; Figure 3 is a side perspective view of a portion of the floor; Figure 4 is a perspective view of a portion of the floor; Figure 5 is a perspective view of a portion of the floor with the formers removed; Figure 6 is a perspective view of a portion of the floor with the formers removed; Figure 7A is a side view of part of a former; Figure 7B is a cross-sectional view of a former; Figure 7C is a cross-sectional view of a wider-than-normal former; Figure 8 shows detail of a duct cover; Figure 8A shows detail of an alternative embodiment of the duct cover; Figure 9 shows detail of a strip of perforated material; Figure 10 is an end elevation of a portion of the floor; Figure 11 is a side elevation of a portion of the floor;; Figure 12 is a top view of a portion of the floor; Figure 13 shows the layout of the crop-drying floor; Figure 14 is a side view of the crop-drying floor layout.

Description of the Preferred Embodiments Referring to Figures 1-4, each air supply duct 1 comprises a U-shaped lower portion 2 on which are placed a number of close-fitting duct covers 3, both lower portions 2 and duct covers 3 being formed from folded sheet steel. A portion only of each air supply duct is shown for illustrative purposes, it being intended that each air supply duct 1 should be of sufficient length to reach from a main air supply tunnel (not shown) - for example in the centre of a building to the side wall of that building.

Each duct cover 3 has a downwardly-extending flange 4 on each of its long sides; these flanges assist in the location of duct cover 3 on U-shaped lower portion 2. Each duct cover 3 also has an upstanding flange 5 at each of its shorter edges; these assist in the location of metal formers 6 examples of which are shown in Figures 1-4.

In the illustrated embodiment, downwardly-extending flanges 4 embrace the outer surface of U-shaped lower portion 2. In an alternative embodiment, flanges 4 are situated adjacent the inside surface of U-shaped lower portion 2 and upstanding flanges 5 are slightly wider than lower portion 2 so as to support them thereon. A duct cover suitable for this embodiment is shown in Figure 8A. In this alternative embodiment, U-shaped lower portion 2 can be "overbent" (ie, with its side-walls slightly angled inwardly towards on another) so that, on insertion of the duct covers, the side-walls are pushed outwardly by flanges 4 into a vertical orientation, thus giving a strong and stable overall construction to the air supply ducts 1.

Metal formers 6 are long enough to traverse four air supply ducts 1 and are located so as to cover air outlet slots 7 (slots 7 being formed by the gaps between the spaced duct covers 3, shown most clearly in Figures 5 and 6).

Reinforcing means in the form of mesh 8 is positioned between metal formers 6 and spaced from air supply ducts 1 by means of spacing blocks 9.

Metal formers 6 may be provided with downwardly extending flanges 16, which extend into air outlet slots 7 for strengthening purposes during concrete casting.

The region into which these flanges extend (downwardly) is indicated by reference numeral 17 in Figure 11. These flanges also serve to space U-shaped lower portions 2 at the correct distance from one another during assembly of the floor components.

Reinforcing rods (not shown) may be positioned between air supply ducts 1, and parallel to them, and/or above or below and perpendicular to air supply ducts 1.

Metal formers 6 hang from the steel shuttering by support brackets (not shown) which hold the formers at a constant level (joe, finished floor11 level). This arrangement permits U-shaped lower portions 2 to move up or down within the above-described displacement limits so as to compensate for an uneven base surface.

Once the air supply ducts 1, metal formers 6, reinforcing mesh 8 and reinforcing rods are in position, concrete is cast up to the level of the plane containing the tops of metal formers 6 so as to cast a substantially flat concrete floor. Schematic views of a portion of the crop-drying floor at this stage are shown in Figures 10-12, where concrete is indicated by reference numeral 10.

Once the concrete is in place, metal formers 6 are removed leaving behind air outlets 14 which are tapered in towards air outlet slots 7. These outlets 14 will form the means by which air passes from supply duct 1 into the crop above. In order to prevent crops and debris from falling into the air supply ducts 1, a strip of perforated material 15, for example a fine metal mesh, is positioned over or in each air outlet 14. The strips 15 may be removable so as to facilitate cleaning and removal of dust from air supply ducts 1.

Cleaning may also be facilitated by the provision (during the concrete-casting stage) of one former 18 (shown in Figure 7C) which is wider than normal and is situated at the edge of the planned crop-drying floor. This enables a wider-thannormal outlet 14 to be produced through which dust and other debris can be removed. The strip 15 associated with this outlet 14 need not be perforated, and is preferably not so.

Figures 13 and 14 indicate the layout of a crop-drying floor in position in a storage building. Reinforcing rods 11, nearest to the walls 12 of the building extend beyond the edges of the crop-drying floor in order to tie-in structurally to the building walls. This greatly improves the strength of the structure, in particular in buildings which employ rotary stirrers to ensure even drying of the crop.

Air reaches the crop-drying floor by means of main air tunnel 13 which extends along the centre of the building. Alternatively, air tunnel 13 could extend along one side of the building. Air passes along supply ducts 1 and exits through air outlets 14 so as to dry the crop stored in the building. In order to achieve the desired air flow across the whole floor, it may be necessary to use air supply ducts of differing cross-sectional areas and/or shapes. It is envisaged that all air supply ducts 1 will be, for example, 6 inches wide and normally 6 inches deep (approximately 15cm wide and 15cm deep). However, in order to maintain a constant air flow it may be necessary to use a larger duct, nearer the air tunnel 13 for example, reducing the cross-sectional area as one moves away from the air tunnel.In this way, it may be possible to utilise a combination of air supply ducts, for example 12 x 6 inches, then 9 x 6 inches, then 6 x 6 inches (30cm x 15cm, 22cm x 15cm, 15cm x 15cm, respectively). Alternatively, the crosssectional area of the air supply ducts in this region could be smoothly varying, providing a tapered region on each supply duct in the vicinity of main air tunnel 13. This tapered lead-in improves (ie, smooths) the air flow into the ducts 1.

The crop-drying floor is stronger than those of the prior art by virtue of the steel air supply ducts, the square duct section, and significant reinforcement by reinforcing mesh 8 and reinforcing rods 11.

The floor is also significantly easier to install. Conventionally, end shuttering is used in conjunction with inflatable void formers. A two-stage operation is needed to form the floor; firstly, up to the shuttering and then, secondly, completing the floor up to the walls of the building.

The floor of the present invention is formed by using a shutter with spigots to space U-shaped lower portions 2, clamped to the pre-erected tunnel frame. The downwardly-extending flanges 16 on metal formers 6 (described above) assist in facilitating the correct spacing of the floor components.

Once the floor components are assembled, the floor can be concreted in a single operation from air tunnel 13 to building wall and to external plinth under the grain walling.

Claims

1. A crop-drying floor comprising a series of air supply ducts substantially surrounded by concrete so as to form said crop-drying floor, the air supply ducts extending parallel to the floor surface and located wholly below the same, the crop-drying floor further comprising a series of air outlets in the floor surface extending transversely to said air supply ducts and opening downwardly thereinto, said air supply ducts being each of substantially rectangular, and preferably, substantially square shape in transverse cross-section.

2. A crop-drying floor as claimed in Claim 1 wherein said air supply ducts are substantially parallel to one another.

3. A crop-drying floor as claimed in Claim 1 or Claim 2 wherein said air outlets are substantially parallel to one another.

4. A crop-drying floor as claimed in any of the preceding claims wherein some at least of said air supply ducts are initially formed separately from the concrete floor as a whole, and comprise generally U-shaped lower (in use) portions having respective duct covers, each duct cover being adapted to fit closely to its associated lower portion in spaced relation thereto so as to provide a series of air outlet slots in the otherwise closed duct.

5. A crop-drying floor as claimed in any of Claims 1-3 wherein each of said air supply ducts comprises a generally U-shaped lower portion and an elongate duct cover adapted to fit closely to the lower portion, the duct cover having evenly spaced, transverse slots therein to provide a series of air outlet slots in the otherwise closed ducts.

6. A crop-drying floor as claimed in any of the preceding claims wherein reinforcing means are located within the concrete between two or more of the air supply ducts.

7. A crop-drying floor as claimed in Claim 6 wherein the reinforcing means may comprise reinforcing rods located within the concrete between and substantially parallel to adjacent ones of the air supply ducts.

8. A crop-drying floor as claimed in any of the preceding claims wherein reinforcing means are located within the concrete above or below and substantially perpendicular to one or more of the air supply ducts.

9. A crop-drying floor as claimed in Claim 7 or Claim 8 wherein the reinforcing rods at the outermost edges of the crop-drying floor extend beyond those edges and are adapted to tie-in structurally to the wall of the crop-storage building in which the crop-drying floor is situated.

10. A crop-drying floor as claimed in any of the preceding claims wherein a combination of air supply ducts of differing cross-sectional area and/or shape may be used in different parts of the same crop-drying floor.

11. A crop-drying floor as claimed in any of the preceding claims wherein, in use, each of said air outlets is covered by a removable strip of readily air-permeable e.g. perforated material.

12. A crop-drying floor substantially as described herein with reference to and as illustrated by any appropriate combination of the accompanying drawings.

13. A method of forming a crop-drying floor comprising the steps of i) arranging a desired number of generally U-shaped elongate channel units in position, substantially parallel to one another, so as to form lower (in use) portions of eventual air supply ducts; ii) locating the required number of duct covers on top of the lower portions so as to form a series of air supply ducts, each having air outlet slots therein; iii) positioning a plurality of removable elongate formers transversely across the air supply ducts so as to substantially cover the air outlet slots therein, the formers being of a shape generally tapered towards the air outlet slots and preferably with means for example a generally upstanding flange provided on the duct covers at each edge of the air outlet slots - to facilitate the location of the said formers;; iv) pouring settable concrete around the ducts and formers to a height at or below the plane containing the uppermost edges of the formers; v) removing said formers so as to leave behind, as the concrete sets, defined tapered air outlets opening into the air outlet slots in the ducts; and vi) covering said outlets with (preferably removable) strips of readily air-permeable material.

14. A method as claimed in Claim 13 further comprising the step of providing reinforcing means between one or more of the air supply ducts prior to introducing the concrete.

15. A method as claimed in Claim 13 or Claim 14 further comprising the step of providing reinforcing means between and substantially parallel to adjacent ones of the air supply ducts prior to the introduction of the concrete.

16. A method as claimed in any of Claims 13-15 further comprising the step of providing reinforcing means above or below and substantially perpendicular to one or more of the air supply ducts prior to the introduction of the concrete.

17. A method as claimed in any of Claims 14-16 further comprising the step of structurally tieing-in the reinforcing means at the outermost edges of the crop-drying floor to the nearest wall of the building in which the crop-drying floor is situated.

18. A method as claimed in any of Claims 13-17 wherein said formers are provided with a plurality of strengthening flanges which extend downwardly into said air outlet slots during the casting of the concrete.

19. A method as claimed in Claim 18 wherein the displacement between each former and each air supply duct is variable, in order to compensate for an uneven floor base, the maximum displacement being not greater than the height of the strengthening flanges and upstanding flanges on the duct covers so as to substantially prevent concrete from entering the air outlet ducts.

20. A method of forming a crop-drying floor substantially as described herein with reference to and as illustrated by any appropriate combination of the accompanying drawings.