Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to an enclosed structure and has been devised
particularly, though not solely, as a grain silo.
Most silos and containers or storage bins for large amounts of par-
ticulate solids, are made Erom reinforced concrete or heavy steel plate.
Such constructions require skilled engineering and manpower to erect. They
are also very costly to build.
It is desirable to provide an enclosed structure which may be used
as a grain silo and which is simple and cheap to construct to enable grain to
be simply and cheaply stored at a desired location.
It is therefore an object of the present invention to provide an
enclosed structure which will go at least part of the way towards meeting the
foregoing de iderata in a simple yet ef-fective manner, or which will at least
provide the public with a useful choice.
According to the present invention, there is provided a structure
having a roof and corner-less side wall encompassing a space to receive par-
ticulate solids, said structure comprising: a foundation, a frame fixed to the
foundation so as to be supported thereby~ said frame including a plurality of
generally upwardly extending posts fixed at their lower ends to said founda-
tion and arranged in spaced relationship so as to generally define the position
of said wall, a plurality of girts extending generally horizontally between
said posts; cladding located internally of and fixed to said frame so as to
provide said wall, said cladding including first cladding sheets extending
horizontally around the entire wall to provide a lower wall portion, said
lower wall portion being fixed to said foundation so as to extend upwardly
therefrom to a predetermined height and having sufficient rigidity to withstand
pressures to be applied thereto by said particulate solids and second cladding
sheets in the form of vertically corrugated sheets extending horizontally
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around the entire wall so as to provide an upper wall portion~ said upper wall
portion being fixed to said lower wall portion so as to extend upwardly there-
from and being fixed to said girts so as ~o be supported thereby.
Preferably, the cladding is of corrugated or ribbed cross-section
sheet metal, although many non-metallic materials would also be suitable.
This mode of construction utilises girts to carry the majority of
the stresses imposed by the particulate solids contained therein. The inter-
nal cladding does not carry high loadings over large spans as the girts are
placed sufficiently close together to spread the load. Thus the thickness
of the sheet cladding used is very much reduced from that used in conventional
silos.
The girts are preferably angle or T-section steel members spaced
at suitable distances generally from 100 nun to 900 mm. The girts are attached
to the posts and the internal cladding attached to the girts. The joins of
adjacent sheets of cladding are preferably sealed with a flexible sealing
compound.
The technique of building a silo in accordance with the invention
enables silos capable of holding up to 35,000 kg to be readily constructed.
As the silo is filled there is slight expansion of the walls. This expansion
creates a significant problem if the bottom edge of the cladding is merely
directly secured to the foundations as it will be sheered open or will crack
after a number of loadings~
To overcome this problem the invention provides a lower circumferen-
tial wall of heavier gauge sheet steel secured at its lower end to the foun-
dations and at its upper end to the sheet metal cladding. There is no need,
in general, to have girts around this lower wall if it is made of sufficiently
thick metal. Thus when the silo is loaded the upper end of the lower wall can
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expand with the sheet metal cladding, whilst the lower end remains fixed.
The lower wall is preferably about two metres high although obviously it
could range from 1 metre to~ say, ~ metres depending on the size o~ the silo
being constructed.
The lower wall is preferably formed from a series of plates which
are joined along their vertical intersection.
In order to construct silos in accordance with this invention a very
simple procedure is followed.
The floor and foundations of the silo are prepared. The floor will
generally include one or more conveyor or screw type solids removal units
therein. The
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pos~s are erected hy a crane and secured to the
foundations, by say four bolts. The posts will generally
define a circular area. The girts are attached to the
inside ol the posts. The bottom wall section is erected.
The m.lirl sheet cladding walls are secured to the girts.
The roof ra~ter.s and c]adding are finally added.
~ here the container (silo) is to be~ used for
longer term storage of degradable materials, such as grain
crops, it is desirable to seal the roof to the walls so
that the silo may be filled with a suitable gas to prevent
such degradation. To achieve this, a foil-type membrane
may be laid, sav, under or on top of the roof ra~ters and
attached to the top of the walls.
In a further aspect the invention may broadly be
said to consist in a silo air space bag, comprising an
enclosed bag of flexible materia] adapted to be inserted
into the air space of a grain silo between the grain and
the roof of the silo and a connecting conduit between the
interior of said bag and the atmosphere.
The air bag allows for expansion and contraction
of the gas within the silo due to temperature effects, to
be accommodated. This is achieved by expelling air from
the bag to the atmosphere or drawing air into the bag from
~he atmosphere. This allows a sealed silo filled with an
expensive gas to be stablised over a long period without
the need to have a continual gas bleed or recharge.
There is thus provided a structure which is
inexpensive, lightweight, sealable and of exceptionally
strong construction. The structure can be readily
constructed by unskilled labour with a minimum of
supervision without the need for exotic equipment or
techniques.
Notwithstanding any other forms that may fall
within its scope one preferred form of the present
invention will now be described by way of example only
with reference to the accompanying drawings, in which:
Figures of the Drawings
Figure l is a cross sectional elevation of an
enclosed structure according to the invention;
Figure 2 is a diagrammatic partially cut-away view
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of the structure shown in Figure l; and
Figure 3 is a view of section 3-3 of Figure 1.
Descrlptlon of t_e Prefe.red_Fmbodim~nt
In the preferred form of the invention an
enclosed st.ructure, particularly suitable for use ac, a
grain silo, is constructPd as ol.10~s.
~ pluralitv of vertical posts 1l are provided set
on foundations 12 so as to define the line of a cornerless
wall. In the pr.eferred form of the invention shown in the
accompanying drawings, 8 vertical posts are provided set
so as to define a circular wall.
The upper ends of the posts are arranged to
support roof rafters which may be trusses ~, which extencl
inwardly and upwardly from the posts to be a central
15 receivina member point 14. The posts 11 and rafters 13
mayl for example, be uni.versal beams, alterr)ativelY the
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..t~se~ 13 may be fabricated bv welding from metal
sections .
The vertical posts 11 are interconnected by a
20 plurality of horizontal circumferential girts 15 which may
for example be formed from ang].e iron or T-section as
shown in cross section at 15 in Figure 3. The girts 15
; form continuous circumferential hoops around the line of
the posts 11. The girts mav be attached to the posts 11
by rivetting 23 onto a flange 22 extending from the posts
11 .
The roof framing of the embodiment shown in the
accompanying drawings consist of a series of intersecting
radial rafters which, in turn, support purlins 40.
The roof is covered with sheet cladding material
shown at 17 in Figure 2 which is joined on the line of the
main trusses 13 by a ridge cap 18. The peak of the roof
is provided with an opening 19 provided with a removable
covering 10 to allow the silo to be filled with grain.
The walls of the silo are clad with corrugated
sheet wall cladding 20 extending the height of the wall
and fastened to the girts 15, for example by rivetting or
bolting. The vertical edges of adjoining sheets of
claddiny 20 are lapped, sealed and secured together in a
structural manner; for example by a line of mastic
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compoun(~ and fastening with heavy gauge rivets 50 that
the sheet becomes one homogeneous structural element.
There i5 als~ in the roof system a tie ~ember near
tl-le eaves which attaches to the posts 11 to act both in
tencion and compressioll and completes a structural system
of exceptional strength and lightness since it embodies a
skin membrane construction and provide. a monolithic
stru~ture.
The girts 15 which support the wall sheeting 20
are of sufficient .strength to resist wind loads on the
hhole structure and keep the building stable and at the
same time provide necessary strength to cater for internal
.;-recsures due to the grain 103cl.
The ]ower part of the container wall (see Figure
3) is formed from he~vier gauge steel plates 21 ~oined
tonether at their vertical intersection by means of
overlapping plates (not shown).
The bottom edge of the plates 21 have a horizontal
flange 28 which is fixed to the floor 30 or foundations 29
of the structure bv bolts 27 which secure an overlying
plate 29 on the flange 28.
The upper edge of the plates 21 are attached to a
pair of angle members 30 31 which provide a suitable seat
for the base of the corrugated cladding 20. The seat
formed by members 30 and 31 provides a vertical and
horizontal resistance to the outward forces on the bottom
of the cladding 20. The member 31 is attached to a flange
22 protruding from the post 11.
In Figure 3 the cladding 20 is illustrated showing
the depth of a typical corrugation.
The construction of the wall as shown in Figure 3
ailows for the outwards deflection of the wall at the
intersection of the cladding 20 with the wall section 21
without damage to the bottom of the cladding 20.
There are two major aspects for applications of
the design of the enclosed structure. The first is for a
silo which would be built as part of a grain storage
svstem. It would be a single purpose building for storing
grain. The second application is one for a smaller silo
which might be built on a farm and would have incorporated
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in the design doors so that the silo would become a
multi-purpose building suitable for recreation or storage
of machinery when not in use as a silo. In the first
apolication one of the improved features will b~ the
sealabi1ity of the structure. To achieve sealability a
specia1 sealing member 32 is introduced in the plane of
th~ undel. side of the rooE sheeting :L7. To this sealing
member 32 will be attached flashing and sealing materials
SO AS to enable the structure to be rendered airtight and
so make it suitable for fumigating the content.s of the
silo.
Another feature of this application is the
introduction of a "balloon" or breather bag 33 in the air
space under the roof. This bag is connected to the
atmosphere by means of a breather tube 39 so that as
diurnal temperature affects the gas in the head space 41
above the stored grain 42, gases are not expelled from the
structure during the day due to heating of the yas, or
diluted by air as the gases cool down during the night.
Instead, air is expelled from the balloon 33 during the
: day and drawn into the balloon during the night so that
the expensive gases which are used for fumigation remain
intact and do not require expensive topping up.
In this manner an enclosed structur~ is provided
which is particularlv suitable for the storage of grain in
a simple and yet effective manner and which may also be
used as a farm building by replacing one section of the
wall between adjacent posts by suitable doors.
