CA1136812A - Dome structure, method of forming said structure, and apparatus for forming said structure - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A method for forming a dome-type structure comprising the steps of inflating a support envelope and applying a hardenable foam material to the exterior surface of the support envelope. The foam is permitted to harden around the envelope and the hardened foam material is coated with a perlite-based composition. The perlite composition is permitted to harden so as to form a dome. The support envelope is removed from within the hardened foam.
A dome-type structure comprising a hardened foam layer coated with a perlite-based copmposition is also disclosed.
Apparatus for constructing a dome-type structure which comprises a carriage support upon which the dome-type structure is to be built. The construction support comprises a track. A support envelope is provided as well as an envelope carriage adapted to rotatably position the support envelope above the construction support. The apparatus further comprises means for inflating and deflating the support envelope and means for rotating the envelope carriage.

Description

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 ' ~ ~
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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 .
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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 - ~ .

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~ ~ ~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 _~;_ 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 ~

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 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 ~, ~ 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 ~.~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.

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Claims (28)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for forming a dome-type structure comprising the steps of:
a) inflating a support envelope;
b) applying a hardenable foam material to the exterior surface of said support envelope;
c) permitting said foam to harden around said envelope;
d) coating said hardened foam material with a perlite-based composition;
e) permitting said perlite-based composition to harden to form said dome; and f) removing said support envelope from within said hardened foam.

2. The method as defined by claim 1 further comprising the step of slicing the hardened foam of step c) into a plurality of hardened foam slices prior to the step of coating said hardened foam with said perlite-based composition.

3. The method as defined by claim 2 wherein said hardened foam is sliced by means of a cutting means mounted on an arch aligned to conform to the exterior of said hardened foam, and said slicing step is performed by passing said cutting means along said hardened foam.

4. The method as defined by claim 3 wherein said arch extends across and above the diameter of said support envelope.

5. The method as defined by claim 2 further comprising the step of disassembling the hardened foam slices prior to coating the hardened foam with said perlite-based composition.

6. The method as defined by claim 5 further comprising the step of transporting said hardened foam slices to a distant location and reassembling said slices prior to coating said hardened foam material with said perlite-based composition.

7. The method as defined by claim 6 further comprising supporting said reassembled dome by means of an umbrella-type support prior to coating said hardened foam material with said perlite-based composition.

8. The method as defined by claim 1 wherein said support envelope is removed from within said hardened foam after said foam has hardened, but prior to coating said hardened foam material with said perlite-based composition.

9. The method as defined by claim 1 wherein said support envelope is supported on a rotatable carriage support, and whereby said foam is applied to said support envelope while said envelope is being rotated on said platform.

10. The method as defined by claim 9 wherein said inflated envelope is arranged adjacent to an arch, said arch comprising means for applying said perlite-based composition to coat said hardened foam, said method comprising the step of rotating said envelope while coating said hardened foam material with said perlite-based composition.

11. The method as defined by claim 10 wherein said arch is arranged to extend across a diameter of said envelope.

12. The method as defined by claim 1 wherein said foam is polyurethane foam.

13. The method as defined by claim 11 wherein said arch further comprises means for slicing said hardened foam and said method comprises rotating said arch to a given position, and slicing said hardened foam.

14. The method as defined by claim 13, said method further comprising rotating said hardened foam to a plurality of different positions and slicing said hardened foam at each of these positions.

15. The method as defined by claim 1, further comprising the step of coating the inner surface of said hardened foam with a perlite plaster after removing said support envelope to flameproof the interior of said dome-type structure.

16. Apparatus for constructing a dome-type structure comprising:
a) a carriage support upon which said dome-type structure is to be built, said carriage support comprising a track;
b) a dome-shaped support envelope;
c) an envelope carriage adapted to rotatably position said dome-shaped support envelope above said carriage support;
d) means for inflating and deflating said dome-shaped support envelope; and e) means for rotating said envelope carriage.

17. The apparatus as defined by claim 16 further comprising an arch positioned adjacent to said envelope carriage.

18. The apparatus as defined by claim 17 wherein said arch is stationary and comprises means for applying a hardenable foam material to the exterior of said support envelope.

19. The apparatus as defined by claim 18 further comprising means for slicing hardened foam material formed upon the exterior surface of said support envelope.

20. The apparatus as defined by claim 16 wherein said , envelope carriage comprises rollers to guide said envelope carriage on said track as said envelope carriage is rotated.

21. The apparatus as defined by claim 20 wherein said envelope carriage comprises a plurality of outwardly-extending spokes and reinforcement members for reinforcing said envelope carriage.

22. The apparatus as defined by claim 18 wherein said arch comprises first and second arch segments extending across said support envelope.

23. The apparatus as defined by claim 22 wherein said means for applying a hardenable foam material is a foam applicator, and said foam applicator is mounted on a track in said first arch segment.

24. The apparatus as defined by claim 23 wherein said first arch segment comprises drive means for driving said foam applicator along said first arch segment for applying a hardenable foam material to the exterior surface of said support envelope, said foam applicator being adapted relative to said track in said first arch segment whereby said foam applicator is advanced along the circumference of said support envelope.

25. The apparatus as defined by claim 24 wherein said second arch segment further comprises means for slicing hardened foam material formed upon the exterior surface of said envelope.

26. The apparatus as defined by claim 25 wherein said means for slicing said hardened foam material is a saw.

27. The apparatus as defined by claim 26 wherein said second arch segment comprises drive means adapted to drive said saw along a track in said arch for cutting said dome of hardened foam material formed on said support envelope into a plurality of slices.

28. The apparatus as defined by claim 27 further comprising automatic control means adapted to regulate the speed of rotation of said support envelope as a function of the position of said foam applicator.