CA1158954A - Multiple layer insulation cover - Google Patents

Abstract

MULTIPLE LAYER INSULATION COVER

ABSTRACT OF THE DISCLOSURE

A multiple layer insulation cover for preventing heat loss in, for example, a greenhouse, is disclosed. The cover is comprised of spaced layers of thin,, foil covered fabric separated from each other by air spaces. The spacing is accomplished by the inflation of spaced air bladders which are integrally formed in the cover and to which the layers of the cover are secured. The bladders are inflated after the cover has been deployed in its intended use to separate the layers of the foil material. The sizes of the material layers are selected to compensate for sagging across the width of the cover so that the desired spacing is uniformly maintained when the cover has been deployed. The bladders are deflated as the cover is stored thereby expediting the storage process and reducing the amount of storage space required.

Description

F:t~lL,I) OF Tlll` INVl~N'rrO~

The presen~ invention is directed generally to an insulation cover, which is deployed ancl stored as desired.
More particularly, the present inve1ltion is dircctcd ~o a multiple layer insulation cover for a greenhouse. ~ore specifically, the present invention is directed to a four layer insulation cover for a greenhouse in which the layers are spaced from each other by inflatable air bladders. The spaced.
layers oE material ~ the insulation cover are preferably comprised of a metal Eoil such as aluminum whicll is secured to a polyester scrim. Spaced air bladders are incorporated in the cover and these bladders are in1ated once the cover has }~een dcployed to space the layers. Tlle cover is stored on a suitably driven roll and as the cover is retracted onto the roll, -the air `~ l5 bladders are deflated.
In use as a greenhouse insulation cover, the multiple layer cover ls stored on a roll above the level of ~the growth in the greenhouse. When the sun sets in the . .
evening, or at any other time such as an overcast day, the ~ 20 cover is deployed to prevent heat loss through the roof of - the greer)house. The: air bladders, which are inflated after the cover has been deployed, act to separate the layers of the cover, thus crcated air spaces between the layers to form an eEfective insulation cover WiliCh retains`heat in t1~e ~recn-house.

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DLSCI~II'l`:CON O~`'I`IIE rRIOR A~'L`

Th~ risiny costs oE Euel have created a severe problem Eor tlle yreenhouse industry. qIhe structure oE the c~reenhouse, t~hicIl allows maximum sunlicJIlt durincJ the day, also allows a cJreat deal of heat to escape durinc; the evenin~.
Approximately 10,000 acres are presently under glass in the United States; and as the costs of fuel oil and other sources oE energy increase rapidly, the cJreenhouse owner is quickly being pushed -to the pOillt where he cannot continue in operatio~
The problem oE heat loss in greenhouses has been recognized and the use oE covers for greenhouses is known generally in the prior art. In one form, these covers are flexible transparent sheets which are securecd to the roof ~15;~ oE the cJreenhouse on the exterior thereo and are inElated by sultable means to provIde an air space between the cover and the roof. Another device for cutting down on heat loss ~ -durinc~ the night lS the use of insulati~ng pànels of materials such as expanded foams or the llke. These panels are either ~2~0; ~ cut to shape and put up 1n the evening and taken down in the morning or are arranged in a~man~ner similar to venetlan blinds so that they are opened during the day and closed at ~icJllt.
A recent attempt at reducing greenhouse heat Ioss -:
is shown in U.S. Patent No. 4,0~4,648 to Charles C. Cary. The - Cary patent is directed to an insulation system for greenhouses and the like an~ is comprisecl oE a flexible sheet oE material which is ~ouncl around a roll, is deployed at night, and is ; ' ~ ~589~

s~orecl du~ (J tll~ clay. I~olls oE this materlal are~ placed longituclinally aloncJ the ].encJth oÇ the cJreenllouse ancl are unrollecl across t.he greellllouse. 'l`he eclges of the flexible sheet are disposed cJenerally in a channel or bo~ at either side ancl a cogcJecl wheel asscmbly may be used to clel)loy the sheet. The Cary patent also discloses a system Eor opening the cover in response to SllOW accumulation on the roof of tlle c~reenhouse.

The use of various heat retaininc~ structures and elements is ~lso known cJellerally in conjunction with building windows, swimming pools, and other such facilities.
These structures are often in the form of solid panels which can be moved from a storage location to a use location by some suitable means. Alternatively, these structures may be a flexible sheet of material which is stretched or other-wlse secured across the area to be protected.

SUMMARY OF T~IE INVENTION
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It is an object of the present invention to provide a multiple layer insulation cover.
~nother object of the present invention is to provide a mul-tiple layer insulation cover in which the layers are malntained in spaced array by inflatable air blàdders.
A further object of the present invention is to provide an insulation cover for use in a greenhouse.

t 1589~4 Still another o~ject of the present invelltion is to provide all insulation cover havincJ a positive ~dge seal be~ween tl~e cover and a support track.
Yet a further object of the present invention is to provide a covcr which is efEective ~o reduce heat losses by convection, conduction, and radiation.
~s will be set forth incJrea~er detail in a description of a preferred embodiment, as set ~orth hereinafter, the multiple layer insulation cover in accordance with the present invention is comprised yenerally of four layers of metal foil sccurecl to polyester scrim. rl`he ~our layers are joined, alony their lonc~itudinal sides to inflatable air ~ bladders. ~s the bladders are inflated, the multiple layers ; are caused to separate thereby creating air spaces between each layer. The lonyituclinal edges of the cover terminate in generally T-shaped strips which cooperate with supports such as PVC piplnq or the like havlng an axially extendlng slot. The top of the T-shaped strip is placed within the ` support piping with the ley~of t~le T extendiny out through ~the slot in the pipe. Suitably spaced reels, driven by electrlc motors or the like, are~placed~at elther end of the area in wllich the cover ls to be deployed to move the cover between its stored and deployed positlons.
In contrast with known yreenhouse insulation ~25 covers which are in the form of solid sheets or panels, the multiple layer insulation cover in accordance with the present invention is flexible and can be stored on a roll when not in use. This facilitates the deployment of the cover in a short period of time with little effort. ~urthermore, the stored ;~ cover takes a minimum amount of space, thus when used in a 1 ~89~4 greenhouse, allowincJ full utili~.ation oE the space within the greenhouse.
As was discussed previously, a Elexi~le greenhouse cover is sllowll ge~nerally in U.S. Patent No. 4,064,648 to Cary.
This ~atent shows a sinqlc or c~ou~le laycr cover witll, in the double layer cover, the two lavers being separated ovcr their entire areas by air pressure. In contrast, the multiple layer insulation cover in accordance with the present invention is ~ormed oE spaccd layers with the spaci.ng beinc3 accomplished by inflatable air bladders along the edges of the cover. These inElatable bladdcrs allow the eclual spacing oE the four layers.
Spacing oE more than two layers could not be obtained with the Cary device unless the pressures between the layers were ~accurately controlled. By inflating only elongated -tubes LS instead oE the total area between the cover layers, the size of the blowers re~uired can be reduced, thus reducing initlal cost and operating expense. Additionally, the tubes are more rapidly inElated and deflated to Eacilitate deployment and storage of the cover.
~ In the cover set forth in the Cary patent, there are provided a plurality of separate covers, each of which ~ extends transversely across the greenhouse. Contrastingly, ; in the multiple layer insulation cover of~the present invention, the cover extencls longitudinally along the length oE the grecnhouse. This type o~ deploymen~ clreatly reduces the len(3th of thc edges that must be sealed to prevent escape of heated air. Each lon(jitudinal edge oE the cover oÉ the present invention ends in a T-shaped strip which rides in a support such as a hollow tube having an axially extending slot. The 95~ .

cooperation betwcen t11e tol? of the ~r-shaped elcmcnt and the hollow support, orms a positive sea]. whlcll prevents escape of heated air. The short transverse ends of the cover can be sealed by any suitable means and this is a small area to seal in colltrast to the lonc~itu~linal e(l(~es.
'l`he material used to construct the muitiple layer insulation cover in accordance with the present invention is preferably a flexible metal foil adhered to a polyester scrim. This material is readily available commercially, is easy to work with, is durable, and is not expensive. Thus, the cover which is produced is also loncl wearing and durable.
Its initial cost and upkeep costs are low in comparison to the cost of heating fuels so that the costs of installing and operating an assembly usiny the multiple layer insulation ~ cover of the present invention are attractive to the owner ~of a greenhousc or the like.
S1nce the mater1als~used 1n the construct1on of the cover are durable and highly flexible, the cover can be rolled~on a storage roller and will require little space~
20 ~ Repeated deployment~and storage of the multiple layer insulation :
~ cover, as would be required in day to day usagej will not ~ :
cause the materials to wear out ra~idly, thus assuring the owner of the fac1llty in which the cover is used of having an effective, durable~and trouble free cover which is easily and rapidly deployable to prevent heat losses and to thereby ,.
substantially reduce fuel costs in a ~reenhouse, warehouse, or any sim1lar area having heat loss problems.

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i3R1~1~ Dl;SCI~:[1''1`ION Ol;`'1`11~ W~IiGS

While the novcl Eeatures o~ the multiple layer insulation cover in accorda1lce with the present invention are set Eorth with particularity in tlle a~ ellded claims, a full and complete understandi1lg of the ~?resent invention may be had by reEerring to the description of a pre~erred emboclirnent as set iorth hereinafter and as seen in the accornpanyiny drawings in which:
Figure l is a schematic perspective view, partly in section, and witll portiolls rellloved for clarity of a multiple layer illsulatioll cover in accordance wit1l the present invention, the cover beinc~ deployed in a greenhouse; and FicJure 2 is a perspective view, partly in section, ` show1ng a portion of a multiple layer insulation cover in lS accordance with the present invention.

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DESCRIPTION OI ~ PREl~ERRED ~MBO~IMENT
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Turning initially to ~igure l, there may be seen generally at l0, a multiple layer insulation cover in accordance w1th the present invention. In the preferred embodlment, cover 20 ~ l0 is shown deployed in a conventional greenhouse, generally at 12. While the eover l0 will hereina~ter be discussed and described in conjunction with a greenllouse, it is to he under-stood that the invention is not limited to such use. The multiple layer insulation cover in accordance with the present invention can be used advantageously in any area where it is .

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dcsired to reduce. heat loss. ~y way oE cxampl~, tlle cover could be utilize(l in a warehouse to substantially rccluce heat loss ~hrough a poorly insulat~d rooE. Similarly, in a passive solar ho~se with south facing windows, the cover in accordance with the prcsent invelltioll could be uscd to cover the windows when there is no sunlight thereby substantially reducing heat loss. ~ccordingly, while the multiple layer insulation cover will be hereinafter described in use in a greenhouse, its uses ar~ not so limited.
As may be seen in ~iyure 1, greenhouse 12 is of conventional construction and has a plurality of trarlsparent panels 14 which are supported by spaced uprights 16 and roof trusses 18 to form ~reenhouse s~ructure 12 which has spaced longitudinally extending walls 20 and 22 and a peaked roof 24, One end wall 2G of greenhouse 12 may be seell at the right of Figure 1 and it will be understood that the greenhouse would be closed with a second end wall which, for clarity, is not shown. It will also be understood that greenhouse 12 could be shaped generally as a hemicylinder or other known shape~ Greenhouse 12 is also provided wi-th a plurality of spaced benches or supports 28 upon which the plants being grown are placed.
Multiple layer insulation cover 10 is comprlsed, as may be seen in ~igure 1, of four spaced layers 30, 32, 34, and 3G, which ex~cnd bctwecl) tile sicle walls 2() ancl 22 oE
cJreenhouse 12 and which terminate in inflatable air bladclers 38 and 40, which,as will be dcscribed in greater detail hereinafter serve to separate the layers 30-36 when inflated.

._9_ The COVel^ 10 eXtCllCIS lon~i.ku~inally alollcl the lencJth oE the greellllousc 12 and is securetl to the walls 20 ancl 22 by support tubes 42 whicll arc moveably conneetecl to the spaced uprights 16, as will ~e describetl hereirlafter. ~ storage reel 44 is shown supportcd at the Eirst end 26 of gree~ ouse 12 by convcll~iol-al means. .l~el44 extends transversely across the greenhouse side walls 20 and 22 and is rotatable by a suitable power source such as an electric motor 46 which transmits power to rcel 44 throu~h a drive bel-t 48 or the like. It will be understood that there is also providecl a corresponding deployment reél assembly (not shown) which would be placctl adjaccnt'a seconcl end wall of greenllouse 12 and would be similar in structure and operation to reel ~4. Actuation of the deployment reel assemhly wouId cause cover 10 to be deployed in place, as seen in Figure 1, while actuation oE the storage reel assembly 44 would store cover 10 thus permitting sunlight to pass through the transparent panels 14 to contact the growing plants.
Turnin~ now to Figure 2, there may be`seen an enlarged view of a portion of multiple laver insulation cover 10 in accordance with the present invention. As was discussed previously cover 10 is formed by four layers 30 32, 34 and 36 which are spaced bv an air bladder 40. As may be seen in Figure 2, top and bottom layers 30 and 36, respectively of cover 10 are coextensive with a portion of bladder 40. Uppcr 2S all(l lowcr intcrmetliatc layers 32 antl 34 are scc-ur.ctl to tllc outer periphery of''bladder 40 at spaced locations by any acccptable means or method such as stitchin~ or an adhesive.
Bladder 40 is formed of the same material as the four spaced layers and may be su.ita~ly treated to retain air under pressure l 158954 or may carry an air tight plastic inner liner (not shown). The material used in the fabrication of the multiple layer insulation cover 10 is, aS was discussed previously, an aluminum foil secured to a polyester scrim. A suitable material is FO~LON and is avail-able from the Dur~cote Corporation.
The top and bottom layers 30 and 36 and bladder 40 terminate, at their outer edge in a generally T-shaped strip or element 50. Strip 50 includes a top piece 52 and a leg 54 which cooperate to form the T. As may be seen in Figure 2, strip 50 is disposed with its top 52 within the support pipe 42 and with leg 54 passing through an axial slot 56 in pipe or support track 42.
This slot 56 may be angled downwardly with reference to a horizon-tal plane coincident with the sag of the cover thereby reducing wear on the underside of leg 54 o~ T-strip 50. In a preferred embodiment in which the span between side walls 20 and 22 is approximately 24 feet, the slot 56 may be angled downwardly at approximately g D .
Support 42 is shown in the pre~erred embodiment as PVC piping and this is preferred since it is lightweight, durabie, impervious to moisture, and the like, easily installed, and not particularly expensive. It will be understood that other materials could be used for support 42 if necessary. Support 42 is moveably secured to the spaced upxights 16 by any suitable means such as brackets 58 which are held in place by screws ~0 or the like.
Brackets 5~ may be of spring steel or a similar material which will hold supports 42 securely but which will allow the supports 42 to be rotated so that slot 56 can be angled downwardly, as desired, coincident with the sag of the co~er.
A cable 64, such as wire rope or the like, is secured to a leading edge portion- 66 of T-strip 50 by a suitable U-shaped connector 68. Cable 64 runs through the support tube 42 and clQ~ k' --11~

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is sec~red to the deployrnent r~el (not ShOWIl). ~ckuation oE
the c1eployment reel causes the cable 6~1 ~o pull the cover off the storacJe reel ~14. It w.ill be unclerstood that a similar cable would be provided in the other support tube secured to the other slde wall of greenhouse l.0 and that additio1lal cables coul.d be secured at space(1 points across the leading edge of the multiple layer insulati.on cover. It will also be understood that the leading edyes of layers 30, 32, 34, and 36 an~ oE bladders 38 and 40 are all sealed together.
As the cables h4 are wound on the deployment reel, the multiple layc~r insulation covcr 10 is pulled oEE
storage reel 44 and is deDloyed above thc growinc~ area oE
greenhouse 12, as seen in Figure l at a desircd height sufficient to allow access to the plants or benches 28. The leg portion 54 of T-strip 50 passes through the slot 56 in the support pipe 42 and the top portion 52 of strip 50 seals the slot 56 to form an effective air seal.~ As the cover lO
reaches the deployed portion, an air opening 70 in the lower side of bladder 40 lS placed over a correspondi.ng outlet 72 :20 in an air conduit 74. Correspondingly shaped, magnetized ~ flexible yaskets 76 and 78 are provided with gasket 76 : surrounding air opening 70 in bladder 40 and with gasket 78 . being secured about outlet 72 of air conduit 74. ~lr is provided by a blower or fan (not shown) and is directed up concluit 74 in thc directio11 indicatcd by arrow A in Figure 2. This air Elow is sufficient to inElate bladder 40 to a shape as shown in ~igures l and 2. It will be understoocl that the bladdcr along the other longitudinal edge of cover lO is bei.ny concurrently inflated to deploy 1 ~89S~

the cover with the four layers cJcnerally uniformly spacecl.
Oncc m~lltiple layer illsulation cover 10 is deployecl ancl the bladders 38 and ~0 are inflated, there is provided an eEfective means for retaining heat in the c3reenhouse. The Eour layers 30, 32, 34, and 36 are assem~lecl in cover 10 with the reflective side facing upwardly. The air spaces between layers stop concluctive heat loss, the air spaces are still so there is little convective heat loss and the aluminum foil is a poor emitter of heat so there is little radiant heat lbss. I~lith -the cover 10 deployed, the heat remaills in the c~reellllouse. Tllcre is little heat loss due to poor sealincJ since the T-strip 50 and support tube 42 form an eEective seal. Rs may be seen in Figure 2, the spaces between the uprights 16, transparent pancls 14 and support tube 42 can be sealed by suitable strips 80 of insulation such as expanded foam which are permanently secured in place. Suitable means such as suspended drapes or flaps can be providecl alonc3 the end walls of the greenhouse to prevent escape o~E heated air around the reels.
~20 - In a preferred embodiment, in which the width of the greenhouse is 24 feet, the air bladders 38 and 40 are structured to have a circumference of approximately 30 inches.
Top and bottom layers 30 and 36 are in contact with bladder 40 each for approximately 14 inches and the intermediate layers 32 all(l 34 are sl~acecl 2 ~nche.s rum eacll othcr. 'I'his rcsults in a multiple layer insulation cciver in which each layer is spaced approximately 2 inches from the next layer. The air suppliecl to bladclers 38 and 40 is only slightly above atTnospheric , 1 158~

pressure by approximately .G inches of water. ~ small an c~pacity is r~uired and a fan whicll provides 50 Cl~.~ and draws only 50 watts oE power will be ade(~uate to inElate a bladder in several minutes. Sincc thc layers oE cover lO are ve~ry licJht, the forcc o~ cach layer oll the blaclder is sm-lll allcl would be in the orclcr of .089 Lb/in over a 24 foot span with a 12 inch sag at the center of the span. By suitable anaylsis, the length of material to be used to form the four layers can be selected prior to assembly so that the spacing will relnain uniEorm across the entire span. It will bc unclerstood that the use of bladdcrs 38 and 40, thc air pressurc recluired, ancl the amount oE sacJ across the span can be varicd dependincJ on the size of the span. It will also be understood that the slze of the fans can be varied clependincJ on how rapidly it is desired to inflate the bladders. Adclitionally, plural fans can be placed along the length of each bladder. Since these ; fans draw little power, they will be left on when the cover lS deployed thereby insuring inElation of the~bladders and ~ ~ spacing of the layers even if there are minor air leaks.
When the cover lO is to be stored, the fans are turned off and the storage reel 44 is actuated to draw the cover lO ~o the right, as seen in Figure l. The air is forced out of the bladders and the T-strips 50, which are made of nylon webbing or other similar material, are sufficiently flexible so tha~ the top 52 folds adjacent the leg 54 once the T-strip is pulled out of the support 42 adjacent take-up reel 44. The rolling of the cover lO ln this ~ashion reduces wear to a minirnum alld stores the cover in as little space as possible.
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l ~5~4 The mul.tiple layel. .insulcltioll cover in accordance with the present ialvention as set forth hereinabove is an effective, economical, and depellclclble way of greatly reducincJ
heat loss throu(JIl the roo~ oE a c~reellllouse or th3.~0ucJI~ arly other poorly insulclted area 'l~he multipl.c layers 03' ~he cOVe3-provi(le goo(l i.ns~lation capabilities without bulk and with little storaye spacc requirement~ The l.ongitudinally extending air bladders facilitate the spacinc~ o the layers in an effective and economical manner whiIe not requiring large~
capacity fans or i~lowers.
While a preferrcd embodimellt of a multiple layer insulation cover in accordance with the present invention has been set forth hereinabove, fully and completely, it wi.ll be abvious to one o35 ordinary skill in the art that a number of changes in,`for example, the number oE layers, the type of fabric, the drive means for the reels, the shape of the support tubes, and the like, could be made without departinc~ from the true spirit and scope of the invention and that the invention is to be limited only by the fol lowing claims:

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Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A multiple layer insulation cover for preventing heat losses from the interior of a building, said cover comprising:
a.) four layers of flexible cloth backed metal foil;
b.) first and second elongated air bladders in said cover spaced from each other and extending along longitudinal edges of said cover, said layers of said cover being spaced apart from each other by inflation of said bladders;
c.) support tubes extending along the interior of the building, said tubes including axially extending slots and supporting said cover as said cover is deployed in said building;
d.) T-shaped strips secured to outer edge portions of said cover adjacent said air bladders, said T-shaped strips cooperating with said support tubes to support said cover;
e.) means for inflating said air bladders when said cover is deployed to space said layers; and f.) means to move said cover between deployed and storage positions.

2. A multiple layer insulation cover adapted for use in preventing escape of heat from the interior of a building, said cover comprising:
at least three spaced, flexible layers joined together along first and second spaced, parallel edge portions to form said cover, said cover extending transversely across the interior of the building, spaced from, and generally parallel to, a floor portion of the building;
first and second elongated air bladders in said cover, said bladders being secured in said cover adjacent said first and second edge portions of said cover, respevtively, and being inflatable to space said layers of said cover;
means for maintaining said spaced layers of said cover at a uniform distance from each other while-allowing said cover to sag transversely;
support means securing said edge portions of said cover to side walls of the building, said support means including axial slots through which said edge portions extend, said axial slots being angled with respect to the floor of the building coincident with said sag of said cover; and means for slidably securing said edges in said support means.

3. The cover of claim 2 wherein said support means are tubes, said tubes being secured to said building capable of being rotated to vary said angle of said slots.

4. The cover of claim 2 wherein said means for slidably securing said edge portions in said support means are T-shaped strips secured to said edge portions of said cover, a head portion of each said T-shaped strip being carried in said support means and a leg portion of each said T-shaped strip extending through said axial slot and being secured to said cover.

5. The cover of claim 4 further including means to deploy and store said cover.

6. The cover of claim 5 wherein said means to deploy and store said cover are spaced reels, said cover being moveable between stored and deployed positions by actuation of said reels.

7. The cover of claim 6 wherein said T-shaped strips are flexible, said head portion folding into coincidence with said leg portion during storage of said cover.