Note: Descriptions are shown in the official language in which they were submitted.
BI~CKGROUND Ol~ lE IN~iENTION
1. Field o~ the Invention
The invention relates to a dome-type
structure and to a method and apparatus which may be used to
form the structure.
2. Description of the Prior ~rt
U.~. Patent 2,388,701 to Neff entitled
"~ethod and Apparatus for Constructing Shell-form
- Structures", discloses use of nylon and cotton muslin forms
which may be anchored to a floor slab and inflated to form a
semi-spherical shape. The patent discloses coating the form
with a fast-setting plastic material such as gypsum,
plaster, concrete or a "so-called plastic". The plastic
material is set-up to form ~hat is called a preliminary
shell and this shell is then coated with concrete by means
of the "Gunite" method.
U.S. Patent 3,h43,910 to Heifetz discloses
the use of an inflatable form which acts as a support for
materials such as concrete, p]astic matèrials or the like
which is cast or gunned onto the form after the form has
been inflated. The patent is specifically related to a base
ring structure which may be used in conjunction with the
form.
U.S. Patent 3,S14,077 to Lodes discloses an
apparatus for formimg resinous building structures
comprising a surport on which a nozzle is arranged. The
' ~ ~
.
: '
Z
support is mounted on a scarrold whicll rotates the scaffo]c1
with respect to the structure bei~g ~ormed. The scaffold is
mounted at a fixed height above the base of the struc~ure
being formed.
U.S. Patent 3,503,1C7 to Mackie discloses a
building structure having different foam layers in which a
thic~ insulation of foam plastic is sprayed over the outside
of a form to form a shelter. The shelter may be provided
with doors and windows.
U.S. Patent 3,277,219 to Turner discloses a
building structure having ~ foamed plastic material arran~ed
on the inside of an inflatable form.
According to a booklet published by the
Mobay Chemical Company (Copyright l9h3~ entitled Rigid
Urethane Foam...A New Conce~t_in_Structural_Design, a
dome-like structurc is disclosed in which cemént is sprayed
on top of a plastic film lined on its inside with urethane
foam (page 5).
SUMMARY OF THE INVENTION
It is an object of the invention to provide
a structure which may be easily assembled where desired.
It is yet another object of the invention to
provide a structure having excellent insulation properties
which is simple to manufacture and which may be easily
manufactured on a mass production basis.
Yet another object of the invention is to
--2--
.
~ ' ', .
~ J'~
provide an apparatus for manufacturing a dome-type structure
which is simple yet effective and which may be used to
manufacture dome-type housings and the like on à mass
~roduction basis.
A further object of the invention relates to
a method of producing a housing in which it is possible to
prefabricâte â portion of the structure thus making it
possible to simply construct the remainder of the housing on
location as desired.
~hese and other objects are fulfilled
according to the invention wherein a method is provided for
forming a dome-type str~cture which comprises the steps of
inflating a support envelope and applying â hardenable foam
materiâl to the exterior surface of the suport envelope.
The foam material is permitted to harden around the envelope
and the hardened foam material is coated with a
perlite-based composition. The perlite-based composition is
permitted to harden to form the dome and the support
envelope is removed from within the hardened foam.
The objects are further fulfilled according
to the dome-type structure of the invention which comprises
a hardened foam layer coated with a perlite-based
composition.
In one preferred embodiment of the invention
the foam layer may comprise individual slices of foam
material which are joined together to form the foam layer.
The above objects are further fulfilled by
means of ~he apparatus of the invention for constructing a
dome-type structure which co~prises a carriage support upon
which the dome-type structure is to be built~ The carriage
support comprises a track. ~he apparatus further includes a
support envelope and 2n envelope carriage adapted to
rotatably position the support envelope above the carri2ge
support.
Means are provided for inflating and
deflating the support envelope and the apparatus further
comprises means for rotating the envelope carriage.
~RIE~ DESCRIPTION OF THE DRAWINGS
With reference to the annexed drawings:
Figure 1 is a front perspective view of the
dome-type structure of the invention;
E~igure 2 is a cross-sectional view o the
app2ratus of the invention for constructing a dome-~ype
structure;
E~igure 3 is side view of the rollers used to
support the envelope carriage of the apparatus;
E'igure 4 is cross-sectional view along the
lines ~-4 of Figure 2;
~igure 5 is ~ cross-sectional view of the
arch used to support the no~zle used to apply foam along
lines 5-5 of Figure 2;
F~igure 6 is a cross-sectional view of the
arch used to support the slicing means along lines 6-6 of
- ~ .
,~" ~ . .
'- :
.
~ ~ ~3
Figure 2;
Figure 7 is a perspective view of a
partially constructed polyurethane dome;
Figure B is 2 cross-sectional view of the
dome along lines 8-8 of Figure 7;
Figure 9 is an interior cross-sectional view
oE the foam slices being supported by an umbrella support;
Figure lQ is a cross-sectional view of the
coated foam structure;
Figure 11 illustrates the structure of
Figure l0 additionally comprising a wire mesh surrounding
the dome;
Yigure 12 illustrates the section shown in
Figure 11 further encased by a cement coating; and
Figure 13 illus~rates the dome shown in
Eigure 12 with the addition of an interior fireproofing
layer.
DESCRIPTION OF PREFERRED E MBODI ~ENTS
The invention relates to the fabrication of
domes and dome-type structures which may effectively be used
as homes, warehouses, and the like. As used throughout the
specification the hord "dome" or the phrase "dome-type" is
taken to include all such structures and is not to be
limited to any one particular shape. Thus, although the
invention will be described with reference to a
hemispherical dome structure it is to be understood that the
1~3~ 3~
invention is not limited to such a shape and that it may
include structures of various configurations.
Refering to Figure 1, a dome or dome-type
structure 15 is illustrated which has a hemispherical
contour 17. The dome is provided with a canopy 19 as well
as as windows and doors 21. The dome is constructed so as
to be both useful and attractive and it is obvious that the
arrangement of windows and doors may be varied so as to
suit particular needs and tastes.
The dome comprises at least two layers
(Figure 10). The inner layer comprises a foamlike material,
most preferably polyurethane foam. Quite obviously, the
foam selected is one which may be easily applied by means of
known equipment and techniques such as a gun or nozzle and
which is yet both economical and a good insulator. One form
of polyurethane material which may be used in connection
with the present invention is available from NORTH AMERICAN
COMPOUNDING COMPANY and is designated as NB-45 urethanefoam.
This particular polyurethane material has a density of
Z.02pcf, compressive of 35 psi, a heat distortion
temperature of 155C, a water permiability of 1.8
perm-inches, a closed cell percentage of 97%, an initial K
factor of 0.11 and an aged K of 0.15.
The dome, which is preferably made of
polypropylene, is formed by encasing the foam material,
within a perlite-based composition which adds both rigidity
and strength to the structure. A particularly preferred
_~;_
-- 7
composition comprises a cement to perlite mixture in a ratio of
about 9.7:9 when using a HURO~ Portland cement. The two
components of the mixture may be mixed in the conventional manner
by means of conventional equipment. The advantage of such a
composition is its relatively low density, which is an important
factor to be considered, since the foam material is capable of
supporting only a limited amount of weight. Such support is
necessary until the perlite layer has had sufficient time to
harden and rigidify. The perlite layer may be "Gunited" onto the
hardened foam material or applied by any other conventional
technique.
Turning to Fig. 2, an apparatus is disclosed which may be
used to manufacture the dome-type devices of the invention. In
contrast with previous techniques, which have been directed
essentially at constructing individual units on a one-by-one
basis, the apparatus of the invention makes it possible to
construct domes and like structures on a mass-production scale.
As shown in Fig. 2, a polyurethane layer
~,,
~3~
25 is built up on an infla~ed support envelope 29. 1~he
envelope is preferably made of polypropylene and is inflated
by a blower 55 which supplies pressurized air through
conduit 53 into thc air inl~t pipe 5]. ~ lubricant may be
S added to the outer surface of the envelope to prevent it
from sticking to the foam although a lubricant is
unnecessarey when using a polypropylene envelope. ~upport
envelope 29 is supported by an envelope carriage 27 on a
carriage support 33. The shape of the track corresponds to
the shape of the base of the structure being built and in
the case of a hemispherical dome the track will be circular.
~he envelope carriage is provided with rollers 71 received
and guided by a track 70 mounted on the carriage support 33.
The envelope carriage is provided with spokes 28 and
reinforcement members 30 ~Figure 4). These members make it
possible to rotate the carriage by means of a member 99
mounted within a recess in the carriage support 33.
~ctivation of the motor 49 causes the envelope carriage 27
to rotate thus rotating the support envelope 29. The
thickness of the foam layer is preferably between 3 and 8
inches.
An arch 31 comprising two segments 46 and
96a is arranged to generally conform to the outline of the
support envelope 29. Arch segment 46 is provided with a
chain 3~ capable of advancing a nozzle guide 38 along the
circumference of the segment. In so doing, a nozzle 37 is
advanced along the circumference of the support envelope and
_~_
~3~
is able to supply a foam material onto thc envelo~e at
substantially right angles wl~ile the sup~ort envelope itself
is being rotated by means of the motor 49. Thus, by
starting the nozzle guide 35 adjacent to the carriage
support 33 and advancing it upwardly at a rate corresponding
to that necessary to produce a layer having thc desired
thickness for a predetermined rotational velocity of the
support envelo~e a layer of foam material 25 is built up
along the entire surface of the support envelope 25. The
foam applic~tor 35 is advanced by means of the nozzle guide
38 and the chain 39 upwardly to a level just beneath the
apex of the dome so as to provide for an opening 16 (Figure
9). The purpose of this opening is to facilitate the
deflation of the support envelope 29 when such is desired by
means of a reversal of the blower 55. The opening 16
prevents the creation of a vacuum within the dome which
would complicate removal of the support envelope 29. The
support envelope may be removed after the foam material has
hardened sufficiently so as to be self-supporting.
Arch segment 46a is similar to segment 46 in
that it is provided with a chain 41 for advancing a slicing
means 43 along the circumference of the support envelope ~9.
~`he purFiose of the slicinS means 43 is to slice the foam
material, once it has hardened, so as to form individual
slices which may be easily stored, transported, and then
reconstructed (Eigure 7). ey moving the slicing means 43
down along the hardened foam layer 25 by means of the
slicing means guide ~5, a saw or cutting device such as 2
saber saw slices the harden~d foam material into discreet
segments. Quite obviously, the slicing operation is
performed while the enve]o~e carriage 27 is in a stationary
position Upon completion of its movement from the apex of
the envelope to its base (or vice-versa), the slicing means
~3 is then raised once again to the apex position, the
support enveloFe is rotated to the next position by means of
motor 49 and slicing means is once again lowered. This
operation is repeated until the hardened foam layer has been
disected into as many slices as desired.
The entire system may be automated by means
of an automatic control system 59 adapted to control motor
49 as well as chains 39 and 41. The two components used to
form the polyurethane foam, i.e., resin and isocyanate are
injected through the nozzle by means of a pumping system 55
and feeder lines 63 supported by a guide pulley 61. ~he
components of the polyurethane are stored in storage drums
57 and 58.
~0 Although the invention has been illustrated
with respect to the use of chains or the like as the means
used in conjunction with the arch other means may obviously
be used to guide the nozzl~ and slicing means.
Figure 3 merely illustrates rollers 71 used to support
envelope carriage 27 and to guide the carriage along track
70 mounted on carriage support 33.
As seen from Figure 4, the envelope carriage
--10--
~
27 is provided with spokes 28 and reinforcement members 30
whose purpose it is to reinforce the carriage and rigidify
it.
Eigure 5 illustrates the track system used
to support the foam applicator 35 along the arch segment 46.
A chain drive 39 is advanced along tracks 40a and 42a so as
to move the foam applicator with its nozzle 37 directed
towards the surface of the support envelope 29.
Likewise, Figure 6 illustrates the arch
segment 46a, in cross-section, used to support and advance
the slicing means 43 along the hardened foam layer. Once
again a chain drive 41 advances along tracks 42 and 44 thus
moving the slicing means.
After the hardener foam material has been
sliced as desired, it is ready for storage or shipment and
reassembly. By virtue of the fact that the slices may be
easily stored and transported it is possible to construct
the foam form at a location most conduc ive to good
formation and to then transport the finished slices to the
desired construction site. Thus, the process of the
invention lends itself to the fabrication of units to be
used in unusually extreme climates where the construction of
the hard foam layer would normally be complicated by virtue
of moisture, wind and temperature conditions.
Of course, the invention is not limited to
the use of foam slices and, when desired, the slicing
operation may be omitted thus obviating the need for arch
--11--
segment 46a in Figure 2. l~he resulting ~Ise~i-arch~ ~ay then
be supported by means of a pole extending through the
envelope. In such a case, after the foam has been hardened
the perlite layer is immediately applied to form the
dome-type housing.
~ s may be seen from Figure 7, the slices are
easily reassembled on site. Each of the slices may be
routed to form a groove 34 adapted to receive rigid piping
32 (~igure 8) between each of the slices 20. ~he pipes 32
may be either solid or hollow and are preferably made of a
high rigidity solid polyurethane foam material. To further
insure good insulation an adhesive sealant is preferably
used in conjuction with the pipe 32 so as to form a solid
joint bet~een each of the slices 20. One adhesive which may
be prferably used is MASTIC #ll available from the DOW
CHEMICAL COMPANY.
Once having been assembled, the slices are
now ready to be coated with the perlite-based composition.
The perlite layer is preferably about two inches thick.
Although other compositions may conceivably be used within
the scope of the invention, as was pointed out previously,
the perlite composition is preferred bacause of its highly
desirable insulating and low density properties. Where
needed, an umbrella support 75 comprising a central support
77 and members 79 may be used in conjunction with a support
bar 81 to provide temporary reinforcement while the perlite
composition is being Gunited onto the slices. As seen in
-12-
~, ~ 3~
~igure 9, utility connections 1~ are schematically
re~resented and illustrate the ease with which utility lines
and the like may be led into the housing. The utility lines
are led throuqh the base 23 which may itself merely comprise
a contrete slab.
~ y virtue of the unique combination of the
layers of the inventon, it has been possible to achieve a
remarkably constant temperature throughout the entire
structure.
Figure 10 is a cross-sectional view of the
housing once the perlite composition has been Gunited onto
the foam support.
~s may be seen from ~igure 11, a wire mesh
may be a~plied over the entire surface of the Gunited layer
to provide reinforcement prior to the application of
additional layers of material if such are desired. The wire
mesh 73 is preferably 6-6 l~-ln W/l^~. The mesh is secured
around the structure by means of peg 2~ secured to hooks 72.
~igure 12 illustrates the application of a
layer of cement into which the mesh becomes molded. This
overcoat 26 may be made of any suitable material depending
on the function it is to serve. Cement, additional perlite
composition and the like may all be used. l'he final
exterior of the shell may then be painted as desired.
Figure 13 illustrates the addition of an
inner coating 36 which is a fireproofing layer made of
perlite plaster. ~s an additional insulating feature, a
-13-
~.~3~
va~or ~arrier may be applied bet~een the inner coat 36 and
the slice 20. lhe vapor barrier serves to further prevent
the seepage of air and moisture into and out of the dome.
Additional reinforcement of the dome may be
provided by means of rein~orcement bars or collector rings
arranged at the base of the dome.
Canopies and the like m`ay be added to the
dome by the use of forms which are subsequently covered with
foam and perlite composition. The forms may be made of
metal, plywood, as well as conventional construction
materials.
The invention has been described with
respect to particular materials, apparatus, and techniques.
It is to be understood, however, that the invention is not
limited to the particulars disclosed and is to be construed
in light of the claims.
-14
'
:
