Method for applying membrane-covered rigid foam to building surface

An apparatus for in situ preparing and applying foam to a surface, such as a roof, and at the same time applying a membrane onto the surface of the foam, produces a foam-membrane sandwich having an upper surface of controlled smoothness and thickness or pitch, which sandwich is firmly held to the treated surface. The apparatus is normally self-propelled and may be automatically controlled so as to be advanced across the surface to be coated with membrane-covered rigid polymeric foam, preferably of polyurethane foam, as the curing pre-foam and covering membrane are applied. In preferred embodiments of the invention the membrane is a roofing felt or fiberglass web, mat, treated paper or cloth fed from the apparatus from a roll thereon, producing with the roof or other surface to be coated, a form into which a curing pre-foam is deposited as the apparatus is advanced. Also within the invention are processes of producing a membrane-covered, rigid polymeric foam covering on surfaces, such as roofs, by application of a curing pre-foam to the roof under a covering, smoothing and height- or pitch-establishing membrane to which the foam adheres upon curing.

This invention is of an apparatus for the application of a membrane-covered 
polymeric foam to surfaces. More particularly, the invention is of an 
apparatus for the in situ preparation of foam-membrane sandwich insulation 
of controlled smoothness, thickness or pitch and application thereof to a 
surface, such as a roof, by depositing a curable or curing pre-foam of a 
rigid polymeric material onto the surface while simultaneously laying a 
cover membrane on the foam. The invention also relates to a process for 
producing such foam-membrane sandwiches and applying them to surfaces, 
such as roofs. 
Conventional building insulation, such as that for roofs and floors of 
buildings, is usually of conveniently sized panels of fibrous, cellular, 
vegetable or mineral board which is partially or completely cemented or 
otherwise mechanically attached to a structural deck or sub-deck. Such 
insulation is usually protected by a waterproof membrane such as built-up 
roofing. However, leakage through the membrane, liquid water and water 
vapor movement into and through the insulation space, repeated freezings 
and thawings and differential thermal movements cause stresses and often 
result in ruptures of the membrane, resulting in leaks, saturation of the 
insulation and damage to the structure and contents, which are especially 
bad because the insulation is not air- or liquid-tight and because leakage 
occurs readily in the seams and spaces between pieces of insulation. 
Because of the disadvantages of the prior art building insulations and 
coatings, monolithic sprayed polyurethane foam insulation for roofing and 
similar applications has recently been favored because, when suitably 
weather protected, such insulation has eliminated most of the mentioned 
problems. Still, polyurethane foam insulation has not been as widely 
accepted as might have been expected, due to the difficulty of producing a 
smooth surface of such a foam by normal hand application techniques. The 
rough surfaces often resulting are aesthetically unsatisfactory and often 
are architecturally unacceptable because of poor thickness control and 
uneven application, leading to low spots which tend to hold water. Also, 
it is very difficult by hand application of polyurethane and similar 
polymeric foams to correct water ponding conditions which may have 
resulted from settling of the building, overloading of spans thereof or 
design and construction errors. Furthermore, the production of foam 
oversprays, which cause harmful depositions of finely divided foam 
particles on nearby structures and vehicles have limited hand spray foam 
applications on outdoor structures, such as roofs, to those days on which 
wind velocity is minimal or to those locations wherein downwind of the 
spraying there are few people, structures or vehicles which might be 
harmed by the overspray. This complicates the scheduling of roofing work, 
results in lost work time and often precludes entirely any such work 
upwind of vehicle parking areas. 
The various disadvantages of the prior art methods for hand applications of 
polyurethane and other polymeric foams to surfaces have been overcome by 
the present invention. Foam oversprays are no longer a problem. The upper 
surface of the applied foam is smooth and by the method of this invention, 
utilizing apparatus described herein, there is producible a uniform layer 
of a foam-membrane sandwich of desired thickness. Furthermore, ponding may 
be avoided and if present on the previous roof structure, may be 
corrected. A perfectly flat roof or one that is pitched to a desired 
extent may be produced. The membrane acts to temporarily protect the foam, 
gives it smooth surfacing and makes it readily capable of being coated or 
taking other permanent finishes or paints. However, if desired, the 
membrane may be removed and the foam may then be directly coated or 
otherwise treated. All these advantages are obtainable by an efficient and 
economical process which may be effected by means of an automatic or 
semi-automatic foam applying apparatus of this invention. 
In accordance with the invention there is provided an apparatus for in situ 
preparation of a foam-membrane sandwich having an upper surface of 
controlled smoothness, thickness and pitch and application thereof to a 
surface to which it is to be firmly held which comprises means for 
depositing a fluid, curable pre-foam of a rigid polymeric material onto 
the surface and means for laying the membrane above the curable pre-foam a 
controlled distance away from the surface or at a controlled pitch so that 
the pre-foam may contact the membrane and bond to it, whereby the surface 
of the foam is smoothed and the thickness or pitch of the applied foam is 
controlled. In preferred embodiments of the invention the apparatus is 
self-propelled, automatically advancing continously or after a sufficient 
amount of foam-membrane sandwich has been produced, is reversible, 
includes means for applying a polyurethane pre-foam together with a 
flexible membrane cover which is preferably a roofing felt or a fiberglass 
web, mat or cloth, has automatic means for adjusting the height of the 
sandwich or the pitch thereof (or both) and contains means for assisting 
in raising most of the machine out of contact with a supporting surface so 
as to facilitate turning it horizontally and positioning it for operation. 
Also within the invention are processes for the in situ preparation and 
application of the described foam-membrane insulating sandwich which 
include depositing the fluid, curable pre-foam of rigid polymeric material 
on the surface to which it is to be applied and between it and a membrane, 
while holding the membrane away from the surface but in such position that 
the pre-foam contacts the surface and the membrane, and moving forward on 
the surface the locus of application of the pre-foam while maintaining a 
portion of the continuous membrane above the pre-foam being deposited and 
in contact with it. Preferred processes are analogous to preferred 
apparatuses previously mentioned.

A semi-automatic apparatus 11 for applying a foam-membrane sandwich 13 
having an upper surface of controlled smoothness and thickness or pitch is 
shown in the drawing in operating position on the surface of a roof 15 to 
which such a foam-membrane sandwich is being applied. As illustrated, the 
machine is in position to begin the application of the insulating sandwich 
to the roof and therefore, one side thereof, the right side, considering 
the direction of motion of the machine, indicated by arrows 17, 19 and 21, 
is resting atop rail 23, which is of a thickness corresponding to the 
desired height of foam-membrane sandwich to be applied to the roof. 
Although roofing apparatus 11 may be manually propelled along the desired 
path, preferably it is motor driven by pneumatic, hydraulic or electrical 
means, with the first being preferred and being illustrated herein. To 
most simply state the function of the apparatus, as it advances in the 
direction of arrows 17, 19 and 21, a fluid polyurethane or other suitable 
polymeric pre-foam 29 is deposited on surface 15 while membrane 31 is fed 
from feed roll 33 and is positioned a desired distance, e.g., 1/2 to four 
inches, preferably 3/4 to three inches, above the roof surface 15 where 
the pre-foam is being applied, thereby confining it within a moving form 
which may be considered to be defined by rail 23 or a previously laid down 
membrane-covered foam deposit or run, not illustrated, membrane 31, roof 
surface 15 with the near edge 13 open but maintained at a controlled 
distance above the original deck surface to permit free extrusion of 
excess pre-foam to that side. 
The pre-foam is preferably a polyurethane pre-foam, in fluid form, capable 
of being "extruded" to the open portion of the "form" opposite the rail or 
previously laid down run or track of cured foam but other foams, such as 
are described in the Modern Plastics Encyclopedia, Vol. 50, No. 10A 
(1973-1974) at pages 125-150, may also be employed, plus other polymers in 
foam form, such as those characterized as polyesters and polyethers. The 
MPE publication is hereby incorporated by reference. A preferred foam 
system is the two-part urethane system identified as NB-45 of the Dumont 
Chemical Corporation, 2126 East 33rd Street, Erie, Pa., with 1/2 to 4%, 
e.g., 1.3% addition of Propellant 12 or R-12 (dichlorodifluoromethane). 
Suitable other components of the system include R-11, silicone cell 
modifier, metal or amine catalyst and other usual polyurethane system 
ingredients. Another useful foamed fire-retardant polyurethane system, 
sold by Owens Corning Fiberglas Corp., is marketed as their spray system 
322 (25 flame spread). 
In making polyurethanes a fluid reacting pre-foam is made by mixing 
together, usually after heating, individual streams of isocyanate, such as 
Papi 135 (polymethylene polyphenyl isocyanate) manufactured by the Polymer 
Chemical Division of The Upjohn Company; Mondur MR (Mobay Chemical 
Corporation) or other polymeric isocyanates based on diphenyl methane 
diisocyanate (crude MDI), and polyethers made by the reaction of 
polyfunctional alcohols with propylene oxide and/or ethylene oxide, 
although reactions may also be between the isocyanate group and an active 
hydrogen supplied by an amine. For rigid foams, the highly preferred foams 
utilized herein, it is often preferred to utilize polyols which are either 
polyethers or polyesters, such as the polyethers formed by the reaction of 
ethylene oxide and/or propylene oxide with trimethylol propane, sorbitol, 
sucrose, pentaerythritol, glycerol and/or aliphatic and/or aromatic 
amines, and the isocyanate most generally used is a polymeric form of MDI, 
although other known isocyanates and mixtures of these are operative, too. 
Note that the polyols employed are of low molecular weights and generally 
have a degree of functionality of at least three. 
The pre-foam components separately pass from pressurized or other supply 
means, such as may be on a truck, not shown, for polyurethane "spray" 
applications, through metering and pre-heating means, not shown, through 
lines 37 and 39 for the isocyanate and resin, respectively, both of which 
lines are enclosed in a protective foam supply hose 41, then through a 
heater 43, which may be provided for adjusting the temperature of the 
reactants to a suitable point so that the cure will be effected in a 
desirable time, then through lines 44 and 45, respectively, and foam hose 
47 to foam gun 49, wherein the pre-foam reactants are mixed and pre-foam 
resulting from said mixture is discharged under the membrane being laid 
down to produre the foam-membrane sandwich. Thus, at the time of 
application of the fluid pre-foam it is confined in the molding form, 
minimizing overspray and carrying away of the foam deposits which could 
otherwise cause damage to nearby parked cars, buildings, etc., especially 
on windy days. The foam quickly cures in place to form a rigid 
foam-membrane sandwich, which is capable of supporting the foam applying 
apparatus during use. 
As is seen best from FIG. 3, a driving motor 51, herein illustrated as a 
preferred reversible air motor, transmits its motion through speed 
modifier 53 (usually a speed reducer) and a suitable drive means 55, 
herein illustrated as a chain drive, to drive rollers 57 and 59. Solenoid 
valve assembly 61 is provided to control the flow of air to air motor 51 
to allow for reversal of the direction of movement of the apparatus. Drive 
rollers 57 and 59 are supported on bearings 63, 65 and 67 which support 
the roller shaft 69. Similarly, "idler" rollers 71 and 73 and the shaft 75 
thereof are supported on bearings 77, 79 and 81. Continuous belts 83 and 
85 are mounted under tension on the respective rollers, with means for 
tensioning the belts being provided, comprising threaded connecting shafts 
87, 89 and 91 and nuts 93, 95 and 97, respectively, for adjusting 
interroller distances. 
A membrane alignment adjustment means is provided 223 on one feed roll 
trunnion to insure that the feed web is properly centered on idler rollers 
71 and 73. 
When the apparatus for applying the pre-foam is moving forward it is seen 
that membrane 31 will be withdrawn from roll 33 and will be held flat by 
belts 83 and 85. Belt 85, held in place by rollers 59 and 73, rests on 
rail 23 to adjust the right hand height thereof and the height of the 
membrane when moving in the direction of arrows 17, 19 and 21, the left 
rear portion of belt 83, under roll 57, rests on the already laid membrane 
foam sandwich but the left forward side of belt 83, under roller 71, 
unless otherwise supported, rests on roof 15. To adjust the height of 
membrane 31 at the left forward portion thereof, as it is held against 
roller 71, there is provided a vertically adjustable bogie 99 of chains, 
belts, wheels, skids, rolls or other devices, which raises the free or 
left edge of the front roller a desired clearance distance to produce a 
sandwich of specified insulation thickness. As illustrated best in FIG. 7, 
bogie 99 includes continuous chain supporting means 101 mounted on, around 
and between driving sprocket 103 and drive sprocket 105. The chain is kept 
under tension by action of turnbuckle means 107 and arm 109 which moves to 
tighten the chain when the turnbuckle is tightened, at which time arm 109 
turns about pin 111. Bogie frame member 113 is connected with the main 
frame 115 through connecting rods 117 and 119, the former being 
controllable in length (height) by leveling air piston-cylinder assembly 
121 and the latter being controllable by corresponding hydraulic locking 
piston-cylinder assembly 123. If desired, instead of the leveling and 
locking piston-cylinder assemblies, screw adjustment or other height 
adjusting means are employed, the left front of the frame and with it the 
left front portion of roller 71 is raised a desired but fixed height above 
the roof level. By locking the hydraulic piston-cylinder assembly in 
position a similar effect is obtainable. Thus, the left forward portion of 
the bogie chain will support this one otherwise unsupported corner of the 
apparatus and maintain the desired position of the membrane and thickness 
of the insulating membrane-foam sandwich laid down. It does this because 
there is held above the roof-contacting point of the bogie chain the 
apparatus frame 115 and bearing 77, held to the frame, in which bearing 
shaft 75 turns and about it rollers 71 and 73. Of course, if desired, both 
bogie chain sprockets 103 and 105 could be moved vertically to set the 
foam height but it has been found to be easier and more accurate and 
therefore, preferable to adjust only the leading sprocket, allowing the 
bogie to be driven on the roof surface. 
With the height of the membrane held the desired distance above the roof 
surface as the foam applying apparatus advances, fluid pre-foam is 
produced by the mixing of the foam components or feeds in mixing nozzle or 
foam gun 49. Such foam guns are well known and are normally manually 
employed for spraying or depositing polyurethane foam mix onto roofs or 
other surfaces to be insulated. Such a foam mixing apparatus may be of the 
type shown in U.S. Pat. No. 3,263,928 and preferably there is employed a 
Gusmer Model D gun with a No. 70 mixing chamber (Gusmer Corporation, Old 
Bridge, N.J.) or equivalent foam apparatus. Such a gun is usually air 
actuated, being normally spring loaded with the valves thereof shut and 
actuatable by a trigger or other means which opens an air supply valve to 
actuate the foam gun valves and permit the discharge of a mixed pre-foam 
components stream. Although the foam could be sprayed or directed to the 
"nip" area between the membrane on the roller and previously applied foam, 
and onto the roof or other surface to be insulated, by application to a 
single location thereon, it has been found to be much more preferable to 
apply the foam by moving the foam gun transversely to the path of the 
machine across almost the entire width of the path on which the foam is to 
be applied. Such application results in more even coating with the foam 
and does not cause any premature curing in certain locations which might 
otherwise bar extrusion of foam past the cured portion to the open end of 
the form defined by the roof, rail or previously laid down foam deposit 
and membrane. 
To cause the pre-foam to be deposited evenly across the path chosen, foam 
applying apparatus hose 47 and the tubes contained therein are flexible 
and long enough to permit the foam gun nozzle to reach to the ends of its 
desired sweep. As is illustrated on FIG. 9, the foam gun 49, with 
discharge nozzle 118 aimed at the aforementioned nip, is mounted on a 
suitable traversing carriage 120, which in turn is mounted on a support 
bar 122 mounted on pivotable mounting rods 124 and 126, the height of 
which is adjustable by loosening or tightening holding lines 127 and 129. 
Roller bearings 131, 133 and 135 facilitate easy movement of the gun 
traversing carriage on the support bar. The carriage is joined at 137 and 
139 to a reciprocating cable 141 which passes through a cable cylinder 
143, in which is contained a piston 145 which moves inside the cylinder in 
response to air flow. A three way solenoid air valve 147 regulates the 
feeding of air to the cylinder, in response to actuation of a roller lever 
microswitch 149. Thus, when the gun moves to one side of the cylinder the 
microswitch is actuated, causing air to be fed to the opposite side of the 
piston and venting it from the side where it had formerly been present. 
When the piston then moves to the other end of the cylinder, causing the 
gun traversing carriage to reach the opposite end of its path, the 
microswitch and the three way solenoid air valve are again actuated, this 
time by reverse control means 151, causing the complementary venting and 
feeding of air to the reciprocating cable cylinder. In such manner the 
foam gun continually traverses the carriage, depositing pre-foam evenly on 
the surface being insulated. Of course, by adjustment of the air feed to 
the cylinder the reciprocation rate can be modified accordingly. The best 
adjustment of the cable, cylinder, actuators and microswitches is such 
that the reach of the gun at the open end is about 1 to 10 inches, e.g., 4 
inches, short of the desired width so that the pre-foam is extruded that 
last small distance. 
Although it is possible to move the present machine forward (or backward) 
manually it is highly preferred that the operation of the machine be 
semi-automatic or automatic and that self-propelling means, such as an air 
motor and speed reducer, for moving the apparatus both forward and 
backward, should be present. Similarly, it is also highly preferable that 
instead of depending on an operator to note when sufficient foam has been 
applied so that the machine may be advanced, this should be done by 
automatic means. Of course, the speed of the machine may be regulated so 
as to move it forward just the right amount continuously with a constant 
rate of pre-foam application. However, it is preferred to have means for 
detecting the "extrusion" of the foam to the "free" end of the "form" and 
upon the detecting device noting the presence of foam at such end, 
indicating that the form is full, signalling the self-propelling means and 
advancing the apparatus at least until the detecting device no longer 
"observes" the presence of foam at such "open" end. Such a detecting 
device may be of any suitable type, such as one which is thermal-, 
conductivity-, or photo-responsive to the presence of extruded pre-foam. 
As illustrated, there is employed a light source and a photoelectric cell 
to actuate the drive motor of the apparatus when polyurethane or other 
suitable foam is present at the open end. 
The operation of the foam-responsive advancing mechanism of the present 
apparatus is best seen in FIGS. 6 and 7. Holder 153 contains mounted 
therein lamp 155 and the holder and lamp are so oriented that the light 
from the lamp is directed onto the surface of polyurethane pre-foam 
extruded to the open end of the form so that the light is reflected from 
the foam back to a photoelectric cell 157, which, upon detection of the 
reflected light beam, actuates an air valve which moves the foam applying 
apparatus forward and, after the apparatus has moved forward enough so 
that the light is no longer reflected to the photocell, causes or allows 
the valve to close so that the forward motion ceases. The holder 153 is 
adjustable so as to be responsive to the reflected light at the desired 
extent of extrusion of the foam. Of course, when the foam is not extruded 
sufficiently, the light beam will not be reflected to the photocell and 
extrusion will continue until it reaches the desired position, whereupon 
the apparatus will be advanced. In some instances, rather than making the 
failure of the photocell to detect foam cause the stopping of the 
apparatus the apparatus will be automatically moved forward a given 
distance each time the photocell does detect the foam. This can be done by 
operation of a time delay solenoid or other equivalent means to allow a 
certain amount of air to enter the air motor each time the photocell is 
actuated and a microswitch is tripped, actuating the solenoid. In FIG. 7 
holder 153 is illustrated on a carrier rod 159 which may be moved 
longitudinally to adjust the position of the light source and 
photoreflective detector. The rod, which is supported by mounts 161 and 
163, is a conduit and contains the electric feed wire 165 to the photocell 
and lamp circuits and a signal wire from the photocell. 
There was previously discussed the means for adjusting the height of one of 
the forward sprockets with respect to the corresponding roller so as to 
regulate the height of the foam sandwich being created. Such height is 
controllable by the leveling air piston-cylinder combination 121 and the 
related locking hydraulic piston-cylinder combination 123 previously 
mentioned. However, the apparatus performs special controlling functions 
with respect to height regulation or pitch regulation which were not 
previously mentioned and will be further detailed here. If all roofs or 
surfaces to which the present membrane-foam sandwich was to be applied 
were perfectly level or accurately pitched it is possible to permanently 
set the sprocket height with respect to the roller heights so as to 
deposit uniform thicknesses of sandwich on the surface. However, roofs are 
not perfect and consequently it is an advantage of the present apparatus 
that it can correct imperfections to produce smooth surfaced flat or 
intentionally sloped roofs. This is done to some extent by the chain 
feature which prevents the forward "outside" sprocket from dipping too 
deeply into holes in the roofs, which would cause severe irregularities to 
be preserved, rather than corrected by the machine. Nevertheless, if the 
roof is level or regularly slanted the present apparatus can be held at 
the desired height by means of the hydraulic locking cylinder 123, the 
height of which can be adjusted by allowing fluid to pass to either the 
top or the bottom portion of the cylinder, allowing a contained piston to 
move down or up, respectively, to the desired position, at which fluid 
flow is halted and the piston is locked in place. To make the apparatus 
automatically control the pitch at which the sandwich is applied, either 
building up or diminishing the sandwich thickness, as may be desired, a 
level detection and control device 167 is provided, which, as illustrated, 
includes a damped pendulum and means for actuating an air feed to the 
leveling air cylinder 121 in response to tilting of the pendulum to 
maintain the desired pitch or level despite roof or other surface 
irregularities. An adjustment is provided in the leveling device for 
positioning contacts of the pendulum controlling the means for feeding air 
to the leveling air piston, thereby allowing adjustment of the slope of 
the polyurethane applied. Instead of a pendulum there may also be used 
mercury tube switches and other means for regulating the desired pitch. 
Normally, while leveling, the hydraulic lock means 123 is relaxed but 
preferably after leveling it takes over the height control until the level 
detection and control device 167 is significantly actuated, this being 
done to prevent hunting and resulting irregularities. 
After application of a strip of membrane-polymeric foam sandwich to a 
surface the apparatus must then be moved to a new position so as to lay 
down the next strip. Such foam sandwiches are usually about 3 feet wide 
although strip widths may be varied, usually being within the range of 18 
inches to 6 feet, preferably from 2 to 3 feet. The apparatus will be of 
considerable weight, usually from 100 to 1,000 lbs., frequently from 200 
to 400 lbs., and because of the contacts of the belts with the membrane of 
the applied sandwich over considerable areas, the substantial weight of 
the apparatus and friction, it has been difficult to realign the apparatus 
for subsequent sandwich strip application. Accordingly, a lifting device 
is incorporated in the apparatus to raise it and the belts thereof out of 
substantial contact with the supporting surface and to facilitate turning 
and realigning for application of the next strip of foam. Such a lifter is 
illustrated in FIGS. 3, 4 and 8, with FIG. 8 best showing the operation 
thereof. Lifter 169 is mounted to frame 115 by affixation of rigid arms 
171 and 173 of the lifter to frame members 175 and 177, respectively. Arms 
171 and 173 each include pivot rods 179 and 181, respectively at lower 
ends thereof, and rods 180 and 182 at upper ends thereof, about which rods 
legs 183 and 185 turn in response to movements of piston rod 187 in or out 
of pneumatic cylinder 191. The cylinder also moves with the piston so that 
legs 183 and 185 move in essentially the same manner in response to piston 
movements. At the botton ends of legs 183 and 185 are shafts 193 and 195, 
each which contains a series of rollers 197 and 199. It will be noted that 
when pressure is applied to cylinder 191 rod 187 moves outwardly, to the 
right in FIG. 8, lowering the rollers into contact with the supporting 
surface and raising the apparatus. Correspondingly, when the pressure is 
removed the rollers are retracted. In retracted position the two sets of 
rollers are located at the "closed" side of the apparatus and in the 
middle thereof, between the pair of belts, which pair of belts is so 
located as to provide clearance for the lifting rollers. In FIG. 8, as it 
is evident, the drawing shows the apparatus elevated and the phantom lines 
indicate the positions of the rollers, piston rods, etc., thereon, in 
retracted position. 
After completion of the laying of the strip of membrane-foam sandwich on a 
roof it is a simple matter to pressurize the pneumatic cylinder, thereby 
placing the rollers in contact with the roof and raising the apparatus, 
after which it can be turned readily, with the plurality of rollers 
facilitating such turning. Note that in turning the machine some of the 
rollers on each of rods 193 and 195 will be moving in opposite directions, 
which capability facilitates placement of the machine in exactly the 
desired orientation. Retraction of the forward sprocket of the height 
adjusting bogie (FIG. 7) may be desirable during realignment of the 
apparatus. 
In addition to the main features of the invented apparatus already 
described, it includes various additional elements and structures intended 
to facilitate most efficient operation thereof in depositing covered 
insulation on roofs. In FIG. 1 there is shown atop the frame and alongside 
the heater an instrument panel section 201 of the frame top which includes 
air supply pressure gauge 203 which indicates the air supply pressure for 
use in the leveling device (leveling air cylinder-piston combination), air 
motor, reciprocating piston-cylinder combination for causing transverse 
motion of the foam gun, the foam gun, knife and apparatus lifter. Such air 
may also be used for feeding the isocyanate and resin components of the 
foam to the foam gun. Signal lights 205 and 207 are to indicate operation 
of the heater and readiness of the foam (desired pressures), respectively. 
Selector switch 209 allows the selection of thickness control or level 
control. Vernier valves 241 and 251 are for regulating the speed of the 
reciprocating mechanism for moving the foam gun and for controlling the 
travel of the main apparatus, either forwardly or backwardly, 
respectively. Switch 215 is a three position (forward, automatic and 
reverse) manual switch for the apparatus movement. 
In FIG. 2 lifting control 217 is a three-way valve adapted to direct air 
into either end of cylinder 191 to move the piston therein, not shown, and 
at the same time to vent air contained in the opposite end of the piston. 
A manually held starting button 219 is provided to initiate the flow of 
foam and to start machine operation (except for forward or backward 
apparatus movement). As illustrated, the feed roll 33 includes a feed roll 
shaft 221 and an alignment adjusting means 223 for moving the shaft 221 
for maintaining the desired alignment of the feed membrane to the front 
idler rolls. In FIG. 4 cut-off knife or blade 225 is shown positioned 
ready to be moved upwardly, when desired, to cut the membrane 31 near the 
end of a run of desired application of foam-membrane sandwich. The cut-off 
blade is preferably saw-toothed so that as the membrane is moved forward 
(to the right in FIG. 4) the points of the blade will penetrate the 
membrane and the blade will cut it, due to the membrane's forward motion 
with respect to the blade. Means, not shown, are provided for raising or 
lowering the blade. In FIG. 9 springs 227 and 229 on reverse control rod 
231 serve to dampen the shock of contact of traversing carriage 120 with 
stops 233 and 235 and result in a more uniform application of the 
polymeric foam, due to the absence of irregular sprays or discharges from 
the foam nozzles which would otherwise result from the shocks of contacts 
with the stops at the ends of the traversing paths. 
Other additional features of the invention include emergency stop means, 
not shown because the mechanism for operating it is self-evident, which 
cuts off all electric power and vents the air systems; membrane-responsive 
means, not shown, which includes a switch with an activating plunger which 
bears against the membrane 31 being fed from roll 33 and which stops the 
operation of the machine if the membrane has been broken or is not being 
fed; audible and visual alarms for indicating inoperativeness or incorrect 
operation of any of the elements of the apparatus; hook or eye means 
firmly joined to the main frame for the fastening of a lifting cable to 
raise the entire unit and place it on a roof where it is desired to employ 
the apparatus; and protective railings and bumpers on the apparatus to 
prevent damage to it by contact with obstructions or walls on roofs. Such 
additional parts of the apparatus are not illustrated because it is 
considered that their structures are clear from the present descriptions 
and in view of the complexity of the apparatus and drawings already, 
addition of further elements would only serve to obscure those already 
described, rather than to clarity the invention. 
In FIG. 10 are illustrated the pneumatic and electrical circuits for the 
apparatus, together with the hydraulic system and various controlled 
mechanical components of the apparatus. Air enters the pneumatic system at 
237, passes through filter 238 and oiler 240 and then is supplied to the 
gun traverse circuit, the foam gun, the main carriage travel system, the 
membrane cutter or web cutter and the pneumatic pitch or thickness control 
system. Although various air pressures may be employed, normally the 
pressure will be between 50 to 200 lbs./sq. in., preferably from 80 to 120 
lbs./sq. in. Instead of air, other gases may be used in the pneumatic 
system or analogous hydraulic, mechanical or electrical systems may be 
utilized but pneumatic controls are normally preferable. The electrical 
system is of 110-120 volts, preferably 120 volts, and 60 hertz but of 
course, 220 volts and other potentials may also be utilized and the 
frequency may be modified, although it will normally be in the 50-60 hertz 
range. Electrical supply 243 feeds the circuits previously described plus 
the various additional controls and indicating signal circuits and the 
hydraulic foam level locking control circuit. 
Filtered and oiled air from source 237 is communicated through line 239, 
throttle valve 241 and solenoid-controlled 4-way valve 147 to the gun 
traverse circuit cylinder 143. Solenoid valve 147 admits air selectively 
to either side of piston 145 to cause the reciprocating action of a foam 
gun mounted in operative connection with the piston. The speed of 
reciprocation of the gun is controlled by adjustment of valve 241. Through 
line 245 from main air supply line 237 air pressure is transmitted to foam 
gun 49 via three-way solenoid valve 247. 
Air motor 51, for operation of the forward and reverse main apparatus 
drives, receives air through line 249, throttle valve 251 and either 
solenoid-controlled valve 253, for forward movement or solenoid-controlled 
valve 255 for reverse movement. Throttle valve 251 controls the speed of 
travel of the apparatus. Solenoid valves 253 and 255 are part of solenoid 
valve assembly 61, illustrated in FIG. 3, and both are three-way valves, 
so as to be able to exhaust air, too. Pneumatic lines 257 transmits air 
power through solenoid-controlled valve 259 to web cutter 225 which is 
actuated by piston-cylinder combination 261. 
Line 263 carries air from main air supply 237 via manual three-way valve 
265 to either end, selectively, of pneumatic cylinder 191 for actuating 
the apparatus lifter 169. The pneumatic pitch- and level-control 
piston-cylinder combination 121 receives air through line 267 through 
either of solenoid-controlled valves 269 and 271, each of which is a 
three-way valve having venting capability. 
In some embodiments of the present invention, not illustrated herein, 
steering control is effected, preferably by pneumatically controlled 
braking of either of belts 83 and 85, by the braking of one of the drive 
or driven rollers. Also, an emergency braking system may be included in 
the apparatus although, as illustrated, provision is made for emergency 
braking by cutting off the air supply to the air motor or by reversing the 
direction of such supply so as to reverse the movement of the apparatus. 
Release of button 219 halts machine operation. 
The apparatus hydraulic system, as shown, is limited to the locking level 
and thickness control circuit or assembly 123. The hydraulic system, a 
small closed circuit, includes a solenoid-controlled valve 273, a throttle 
valve 275, assembly 123 and communicating lines between them. 
In the description of the electrical components of the apparatus wires will 
not be referenced because it is clear from FIG. 10 which wires are being 
referred to and it is considered to be unnecessary to identify them 
further. From electrical supply or source 243 optional heater apparatus 43 
is heated by a resistance heater 277 when switch 279 is closed. 
Temperature control 281 automatically turns the heater on and off, thereby 
maintaining desired temperature. Signal lamp 205 is lit when the heater is 
operating. In a foam supply or ready circuit pressure controls 283 and 285 
allow the passage of resin and isocyanate respectively, to the foam gun 
when these feed components are at the desired pressure and when web 
continuity switch 287 is closed, by contact with the membrane being fed 
from roll 33 over rollers 71 and 73. If the web is discontinuous switch 
287 opens and no electricity is supplied to the foam gun and gun 
traversing circuits. When switch 287 is closed and foam component supply 
pressures are satisfactory ready lamp 207 lights, signalling readiness for 
operation. When the pressure is satisfactory electricity is carried to 
reversing switch 149 which actuates solenoid 289 to operate valve 147 and 
cause the traversing carriage of the foam gun to operate. Also, when foam 
switch button 219 is depressed solenoid 293 opens or closes gun valve 247 
to permit the feeding of foam from gun 49. 
When switch button 219 is depressed the switch closes and must be held 
closed during foam operation to provide "dead man" control, turning on the 
foam gun through solenoid 293 and also transmitting electricity to 
transformer 295 where it is converted to 12 volts and used to supply lamp 
155 which illuminates the foam edge, activating photocell detector 157 
when the foam has been extruded to the edge of its desired travel. When 
the photocell detects the presence of the reflected light it operates 
relay 303 which closes switch 297, allowing electricity to flow in a 
complete circuit through solenoid 299 to open valve 253 and permit air to 
flow to air motor 51, moving the apparatus fowardly. An adjustment 301 is 
provided for desired regulation of the sensitivity of the photocell so 
that it responds satisfactorily to the presence of the foam at the 
extruded end of the form. 
From source 243 electricity is also passed via line 305 and two-way switch 
215 which makes contact at contact point 309 or at contact point 311 or 
remains open, as desired. When contacting point 309 solenoid 299 is 
activated, valve 253 is opened and air motor 51 is driven in a forward 
direction. When the contact is with point 311 solenoid 313 is actuated, 
opening valve 255 and reversing the flow of air to motor 51. Thus, the 
apparatus can be moved forward or backward without operation of the foam 
applying means or, when switch 215 is in the open position and foam is 
being fed, the apparatus may be moved forward with electricity being 
conveyed to solenoid 299 to open valve 253 and pass air to the motor 51, 
due to the operation of detector 157 and relay 303. Additional relays may 
be employed as required to avoid undesired circuit interactions. 
Switch 315, when closed, activates solenoid 317 which operates pneumatic 
valve 259 to deliver air to piston-cylinder assembly 261 and move cut-off 
blade 225, causing the blade to cut off the web when desired. Valve 265 
for the apparatus lifting device is indicated as being hand operated but 
may also be operated by means of a switch and an associated solenoid 
control, not illustrated. 
Selector switch 209 is for level or pitch control, when moved to upper 
position at contact 319, or for thickness or height control of the 
foam-membrane sandwich when moved to lower position at contact 321. If set 
for pitch control electricity is communicated to level or pitch detection 
and control device 167 which is of the pendulum type as illustrated. When 
the pendulum is adjusted to the desired pitch and the machine is operating 
the pitch will be maintained without need for any adjustment as long as 
the front left portion of the chain does not dip or rise, due to any 
surface irregularities. Should the chain dip the pendulum 323 contacts 
contact point 325 and transmits electricity to solenoid 327 which actuates 
three-way valve 271 to move piston 331 in leveling device 121 upwardly, as 
shown, to maintain the desired level by applying a thicker layer of foam. 
Conversely, if the forward left portion of chain 101 is elevated by 
contact with a bump in the roof or other raised surface, pendulum 323 will 
swing backwardly, making contact with contact point 333 and causing 
electricity to flow to solenoid 335, which actuates valve 269 and causes 
piston 331 to move downwardly. Pendulum assembly 167 can be set for the 
desired pitch, with the foam being pitched upwardly, downwardly or 
perfectly level across the path of deposit. Whenever solenoid 327 or 
solenoid 335 is activated, electricity will flow to solenoid 337, which 
will open valve 273, allowing hydraulic fluid, confined in a circuit with 
piston-valve assembly 123, to pass between top and bottom of the cylinder 
through throttle valve 275. Thus, the hydraulic piston will move in 
concert with the pneumatic piston, will dampen movement of the air piston 
and will lock the vertically adjustable bogie 99 at the desired heights 
for application of foam until the apparatus presses the hole or bump and 
until another depression or elevation is encountered. It has been found 
that the use of the hydraulic means is desirable because of the tendency 
of pneumatic means to fail to lock in place because of compressibility. 
For thickness control and adjustment switch 338 may be employed to pass 
air and liquid to the upper or lower portions of the pneumatic and 
hydraulic chambers, respectively, thereby adjusting the height of bogie 99 
with respect to frame 115 and thus regulating the foam-membrane sandwich 
thickness. In the upper position, at contact 339, the thickness is being 
increased whereas at the lower contact point 341 it is being diminished. 
Between the contacts the thickness adjustment is locked since valve 273 is 
closed. 
Of course, although various mechanisms for operating particular parts of 
the apparatus have been described above, variations thereof and different 
operative means may also be employed. For example, in some embodiments of 
the invention instead of using solenoid operated valves, hydraulic or air 
operated valves may also be useful. Instead of employing pneumatic motor 
or piston-cylinder drives, electric motors or liquid-powered motors may be 
used. Similarly, mechanical devices such as springs may take the place of 
some of the driving means herein described. Nevertheless, the described 
structures have been found to be very satisfactory and are considered 
generally superior to the mentioned variations thereof. 
For clarity some elements of the apparatus have not been described in the 
"circuit diagram" of FIG. 10 and in some cases other elements omitted from 
the various other figures have been shown in FIG. 10. This was done to 
clarify exposition of the invention and it is considered that the 
structures are evident to one of skill in the art from the descriptions 
given. 
The described apparatus is useful in field application of a "floated" 
monolithic polyurethane foam insulation on generally horizontal surfaces, 
such as roofs or floors, to produce a controlled thickness and/or slope of 
roofing material with a smooth top surface. Such a surface coating, 
usually about one-half to three or four inches thick, may be employed to 
prevent undesirable energy transmission tnrough the insulated surface, to 
correct leakage and drainage problems and to avoid condensation and other 
moisture problems common to conventional insulation systems. There are no 
panel joints which are locations where membranes covering insulation often 
rupture, causing leaks and allowing saturation of the insulation, with 
resultant loss of insulating ability and damage to the premises. 
When the apparatus and method of this invention are not employed for the 
deposition of polyurethane and similar foams onto roofing or other 
structures, foam oversprays limit application to certain locations and low 
wind conditions whereas with the present apparatus such limits are not 
controlling. By use of the simultaneous membrane application, in addition 
to confining the foam and preventing undesirable oversprays thereof, the 
membrane produces a smooth upper surface and is of uniform thickness or 
slope, as desired. The polyurethane foam cannot readily be made uniform by 
conventional means, as by doctoring or screeding the surface to control 
thickness and smoothness, because although the polymerizing mass or 
"pre-foam" is relatively fluid and mobile before curing it is also very 
tacky and the gas bubbles therein are easily ruptured. During curing or 
solidification the discharged pre-foam may expand to a volume as much as 
thirty times the original volume, usually due to vaporization of the low 
boiling dissolved material therein, such as trichlorofluoromethane and/or 
dichlorofluoromethane to form a closed cell polymeric plastic of low 
density and thermal conductivity and of surprisingly great strength. The 
polymerization, from mixing of the two liquid reactants or foam components 
to setting so that the foam can support the foam applying apparatus, may 
be only a matter of seconds, e.g., from 1 to 30 seconds, usually from 
about 2 to 10 seconds. The volume expansion is normally from 5 to 30 
times, preferably from 10 to 20 times, but other expansion rates are also 
useful. The final density of the foam will usually be in the range of from 
11/2 to 10 lbs./cubic foot, preferably 2 to 5 lbs./cu. ft. and most 
preferably 2.5 to 3.0 lbs./cu. ft. The rigid polyurethane and equivalent 
polymeric foams made normally have k values (k = thermal conductivity = 
heat (B.t.u.) transferred per hour through a one inch thick, one square 
foot area of homogeneous material per .degree. F. of temperature 
difference from surface to surface, the units being (B.t.u.) (in.)/(hr.) 
(sq. ft.) (.degree. F.) from 0.08 to 0.25, preferably about 0.1 to 0.2. 
Such polymers, if of polyurethane, can withstand temperatures of at least 
250.degree. F. in normal application and use. Thus, short term exposure to 
the hot bitumen of conventional built-up roofing, which may be applied 
atop of the membrane of the insulation, can be withstood, especially if 
the upper surface is protected by an impregnated membrane. 
In application at the nip of a roll of suitable membrane material, as it is 
rolled onto the substrate to be insulated, the urethane pre-foam first 
expands upwardly from the substrate, lifting the membrane into contact 
with a generally horizontally disposed flat plane formed by belts or 
platens or other means for restraining the upward rise of the membrane. 
Further expansion of the fluid foam moves it laterally into contact with 
one side of the cavity, the rail or previously laid down side, which is 
closed, so when expansion is complete to such side excess fluid pre-foam 
extrudes from under the opposite free edge of the membrane. Thus, when the 
forward motion of the present apparatus is controlled to hold this free 
edge extrusion fairly constant, complete insulation fill under the 
membrane is assured. This permits accommodation to various insulation 
thicknesses specified and to irregularities in the desk surface, such as 
flutes or corrugations. Further, a controlled directional pitch can be 
given to the top surface, permitting correction of ponded areas on roof 
decks and insuring subsequent proper drainage. 
During use of the apparatus, as the membrane material is fed from the feed 
roll, feeding around and under the front roller and passing under the 
"supporting" belts, it prevents the tacky fresh foam from adhering to the 
leveling belts. Of course, the feed roll and the rolls which move the 
leveling belts are aligned and the roll feed is centered with respect to 
the belt rollers. In normal application of the pre-foam to the nip between 
the roof and membrane the foam nozzle moves parallel to the front belt 
roller and is aimed so that the mixed pre-foam stream is directed just 
below the tangent of the front roller and the membrane and against the 
substrate. There is some splashback against the underside of the membrane. 
The foam injection is thus closely confined and overspray is diminished by 
the shielding membrane, rail and laid down foam. The surface hills and 
valleys, nearly inevitable when polyurethane is applied by hand, are 
eliminated and this allows the use of a lesser quantity of weather 
protecting material than would otherwise be required for hand sprayed foam 
surfaces. 
Control of the thickness of foam sandwich applied is obtained by starting 
the confined edge of the machine along a base, rail or ground strip, on 
the perimeter or centrally located on the surface to be coated and 
extending above the surface the required thickness of the insulation. As 
has previously been described in detail, the opposite or free extrusion 
side of the machine is supported by a vertically adjustable bogie to give 
the required clearance under the membrane for application of the foam. 
After an initial strip of foam is laid, adjoining passes are gauged with 
the confined sides of the machine supported on the free edges of the 
original strips of membrane-insulation sandwich, slightly overlapping 
these. The originally laid foam is somewhat irregular or scalloped in 
appearance at its "free end" and thereby an excellent locking of the later 
laid strip with that first deposited is obtained. 
In normal operation the membrane-foam sandwich is laid about the perimeter 
of a roof or other surface or of a selected area thereof, with succeeding 
membrane strips overlapped about 1 to 6 inches, preferably about 11/2 to 3 
inches on a previously laid strip which serves as an edge thickness guide. 
When the leveling or thickness bogie is on the left side of the machine 
the direction of travel is counterclockwise, starting the length of the 
belt centers from one corner and completing the strip at the far end of 
the roof area. The machine is then backed up slightly, lifted by the 
lifting means previously described, pulled the width of the membrane 
toward the operator, turned counterclockwise 90.degree. and pushed 
sidewardly into alignment with the next edge, after which it is backed 
onto the just completed strip in the corner. The membrane is then pulled 
down under the front roller, overlapping the left edge of the previously 
completed strip. After checking alignment the machine is started along the 
second side of the roof perimeter, completing it at the next corner where 
the turning and realignment procedure is repeated. Such operations are 
continued until covering of the roof has been completed. If the overlap 
distance is changed significantly due to initial misalignment or for other 
reason, the membrane may be cut, the machine backed up and realigned and 
restarted with suitable membrane overlap at the cut end. Alternatively, 
steering means may be utilized to correct the misalignment. In some cases 
a center strip may be used as a starting guide, in which case the confined 
side of the machine is aligned on the center ground and the machine is 
moved to the far end of the roof or surface to be coated, where it is 
backed up, turned 180.degree. clockwise, aligned to about a two inch 
overlap on the center ground and another strip of foam-membrane sandwich 
is applied. Parallel strips may be applied in this manner until the roof 
has been covered. In either of the described operations it is desirable to 
reduce the width of foam gun travel on the last few strips applied to 
avoid excessive overlap or pile-up of foam. 
When interruptions are encountered on a roof such as stacks, vents, 
skylights or roof-mounted equipment, the foam applying machine is stopped 
and the membrane is cut and broomed down flat at the obstruction. The 
machine is then realigned to produce a cross strip of appropriate length 
at a right angle or a suitable angle behind the obstruction, using a 
portable rail for height adjustment. Then the area around the obstruction 
can be hand sprayed to specified thickness by removing the foam gun from 
its reciprocating carriage and the area may be hand trimmed or sanded to a 
smooth plane even with the machine laid foam insulation surface and the 
membrane may be applied. The machine is then realigned on the cross strip 
in the direction of original motion and work is continued. 
Because membrane materials such as roofing felt are normally available in 
rolls of 36 inch width in the United States and Canada the preferred 
apparatus of this invention is designed to accommodate such membranes with 
the level restraint being applied over substantially this entire width, 
although the machine can be designed for other widths, such as 1 meter. 
Because realigning the machine at roof corners involves starting the next 
strip across the end of the previous strip the parallel belt rollers are 
preferably located on about 24 inch centers to permit convenient feeding 
and lapping of the next membrane, using the 36 inch membrane width, 
although other center distances may be desirable with different membrane 
widths. The leveling restraint is thus applied to about six square feet so 
that a toal weight of the machine, including the membrane roll, of about 
250 to 500 lbs. produces a vertical restraining force of about 42 to 84 
lbs./sq. ft. 
The foam system employed preferably incorporates a catalyst, such as a 
metal or amine catalyst, and blowing agent so that the combination thereof 
is capable of substantially complete expansion and initial curing within 2 
to 30 seconds, most preferably about 2 to 6 seconds, so as to permit a 
sufficiently fast and economical machine advance speed. When the foam 
thickness applied is under 11/2 inch, it is often desirable to increase 
the fluidity of the pre-foam by a "frothing" technique, employing 
controlled addition of about 1/2 to 4%, on a liquid volume basis, of an 
auxiliary low boiling blowing agent such as dichlorodifluoromethane to the 
foam system to produce fast expansion and lateral spreading of the 
pre-foam and raising thereof against the restraining forces perpendicular 
to the substrate. Some unrestrained expansion of the foam after passage of 
the apparatus is permissible but normally significant amounts of such 
expansion are avoided. However, if there is such post-expansion it may be 
compensated for by an appropriate reduction of the restrained thickness at 
which the foam is laid down. 
The expansion or rise and the tack free or set characteristics of the foam 
system should be appropriate to the thickness and the ambient temperature 
of application and it is desirable that the foam system be designed for 
use with or without a low boiling propellant such as R-12. Because a fan 
spray pattern is unnecessary in the present operation it is usually 
desirable that the foam ingredient feed temperatures should be slightly 
lower than those normally employed, to minimize possible overspray. A 
slightly slower resultant foam activity is compensated for by better 
retention of the exothermic heat of polymerization under the membrane and 
intimate contact between fresh pre-foam and the already reacting pre-foam 
in the cavity or form under the membrane. 
While other foam systems and foam equipment can be satisfactorily employed 
excellent results have been obtained using the previously mentioned Dumont 
NB-45 foam system with 1/2 to 2% R-12 addition in a Gusmer Corporation 
Model FF Foam Machine with the Gusmer Model D gun and a No. 70 mixing 
chamber at a gun pre-heater setting of 100 to 120.degree. F., a hose 
setting of 100 to 160.degree. F., using 200 feet of three-eighth inch low 
voltage hose, and a foam delivery rate of about 7 to 8 lbs./minute. The 
foam deliveries may be from 2 to 40 lbs./minute, pre-heater settings may 
be from 90.degree. to 180.degree. F., hose settings may be from 60 to 
160.degree. F., and R-12 additions may be omitted. At the preferred 
conditions mentioned a 34 inch width of one inch thick foam is produced 
with a smooth top membrane surface at a forward advance rate of about 5 to 
25 feet per minute, preferably about 10 to 15 ft./minute, producing about 
20 to 100 sq. ft. of insulated deck per minute, preferably 25 to 50 sq. 
ft./minute. The normal foam metering and mixing equipment is designed for 
a substantially constant pre-foam delivery rate, which is typically from 5 
to 25 lbs./minute. Of course, the forward advance of the apparatus is 
inversely proportional to the insulation thickness and width. Also, if 
corrugations, grooves or flutes or low areas in the deck to be covered are 
to be leveled by filling with foam the forward advance must be 
appropriately reduced. Whether or not such irregularities are present a 
void-free insulating fill of foam is signalled by the appearance of the 
foam extrusion at the free edge of the membrane at a point behind the 
front roller where the foam is approaching a non-fluid, fully expanded, 
tack-free condition. The forward advance can therefore be experimentally 
governed by visually regulating the forward speed to hold this foam 
extrusion fairly constant and at constant thickness and width. However, 
where variable thicknesses are required on uneven decks, to correct 
ponding or drainage problems and in similar situations, a variable rate of 
advance is required which is usually overly demanding of the operator's 
attention and therefore, the previously described automated control of 
forward advance is highly preferred. Because the extremely tacky nature of 
the fresh pre-foam precludes mechanical contact means for detecting edge 
extrusion or foam height to control forward rate of travel the 
lamp-photoelectric detection device previously mentioned or other suitable 
non-contacting means which is responsive to the presence of foam is 
utilized. The intermittent advance of the machine resulting leaves a 
slightly scalloped free edge, which is subsequently filled when the free 
edge becomes a confined edge of the next adjacent pass and which helps to 
lock the adjoining passes together. The forward travel feed of the machine 
is adjusted to be slightly faster than is required for deposition of the 
desired thickness or width. By such adjustment, the forward advance is 
automatically controlled even when the machine travels over a fluted or 
corrugated deck or a depressed ponded area which is being levelled. This 
higher speed also allows for depositing a tapered insulation of a design 
where the top surface is deliberately pitched toward or from the confined 
area, such as when correcting drainage problems. 
After application of the smooth surface polymeric foam insulation it may be 
coated with built-up roofing, including alternating plies of roofing felt 
and bitumen and may be topped with a layer of gravel or aggregate. Methods 
of applying such built-up roofing are described in the text Manual of 
Built-Up Roof Systems by C. W. Griffin, Jr. published in 1970 by 
McGraw-Hill Book Company, at pages 75-103. Also of interest in the text is 
the chapter on thermal insulation, at pages 56-74, wherein the application 
of sprayed-in-place plastic foam insulation onto mineral fiberboard 
insulation is described. 
Instead of applying built-up roofings, in some instances the 
membrane-covered insulation layer laid down may be covered with other 
coatings, including sprayed-on polymeric materials. It may also be 
removed, if desired, but in such cases normally the membrane will be 
specially chosen to be of low adherence to the foam and may be surface 
treated to inhibit adhesion. After removal of the membrane the foam may be 
coated directly with built-up roofing material or other substances. 
Although the present apparatus is primarily for the controlled application 
of polyurethane foam insulation on generally horizontal surfaces such as 
roofs or floor decks, with minor changes in the means for supporting and 
advancing the apparatus by cables, chains, ropes or other means it is 
within the scope of this invention that it is adapted to foam-membrane 
applications on steep pitched roofs and similar surfaces, to domed roof 
structures, to vertical walls, such as cold storage structural walls, to 
cylindrical surfaces such as tank surfaces and to ceilings. It is 
considered that from the description herein the means for adaptation to 
such coating problems will be apparent to one of skill in the art. It is 
also within the scope of this invention to utilize the apparatus thereof 
for additional purposes, such as for the application of an adhesive and a 
web on top of it, and to applying adhesive along (without the web) and to 
applying bitumen, elastomers, polymeric foams, silicones, paints, finishes 
or other materials to appropriate surfaces for moisture transmission 
control, weatherproofing and other purposes, in closely controlled 
application amounts, by substituting a feed of such a material to a 
suitable spray gun on a traversing carriage. In all such applications the 
apparatus provides the advantages of close control of the covering 
thickness or weight applied and greater productivity, by elimination of 
operator fatigue together with the capability of shielding from overspray 
and minimizing of exposure of an operator to noxious or toxic fumes and 
droplets. 
The following example illustrates the process aspects of this invention, 
using the described apparatus. 
EXAMPLE 
Utilizing the apparatus illustrated in the drawing, with standard weight 
saturated felt roofing (8 lbs./square in one case and 30 lbs./square in 
the other) of a 36 inch width, the machine is operated so that the 
traverse of the gun is 30 inches and a two-part polyurethane foam system, 
NB-45 (Dumont Chemical Corp.), with 1.3% of R-12 auxiliary blowing agent 
blended with the pre-foam reactants, is mixed in the mixing nozzle and 
discharged onto the nip area between the felt being applied and the roof 
so that a two-inch height of foam covered with the membrane is deposited. 
The electric supply for the machine is at 120 volts and 60 hertz and the 
air pressure supply is at 100 lbs./sq. in., with a flow rate capability of 
at least 2-3 cubic feet per minute. The pre-foam reactant tanks are each 
of at least 450 pounds capacity. Of course, to make the two inch height of 
foam a two inch rail is employed. The foam machine utilized is a Model FF 
Gusmer Corporation Machine and the foam gun is a Gusmer gun, Model D. The 
mixing chamber is No. 70 and the pre-heater setting is 110.degree. F. with 
a hose setting of about 130.degree. F., using 200 feet of three-eighth 
inch low voltage hose, delivering foam at a locus of points which move 
forward as the machine advances, at a rate of about 6.3 linear feet per 
minute. The foam produced is of a 1:1 isocyanate:polyol resin ratio by 
volume with amine and metal catalysts, R-11 blowing agent and silicone 
cell controller incorporated in the resin. For the isocyanate there may be 
employed Papi 135, Mondur MR, Rubicon Rubinate M or MDI. Various other 
polyol resins may also be used. When the foam thickness is diminished to 
one inch, the production rate is increased to about 12.5 linear feet per 
minute or about 36 sq. ft. of insulation per minute of a density of about 
2.5 lbs./cu. ft., compared to about 6.3 linear ft./min. and 18 sq. 
ft./min. with the two inch thick insulation. 
The apparatus automatically controls the height and maintains it level. 
When set for a slope of 178 inch per 36 inches, it automatically 
maintains such slope. At the end of travel the lifter is actuated, the 
machine is turned as previously described and is advanced along another 
rail at right angles to the first one in a counterclockwise direction. The 
roof is laid down in this manner, with previously laid strips being used 
as supports in place of the rails after the starting strips are laid. In 
another variation of the invention a center strip is used and parallel 
strips of foam are laid down. Similar operations are effected on slanted 
roofs, vertical walls and floorings. In place of polyurethane foams, other 
foams, such as epoxy foams and those previously mentioned are utilized, 
with fire-retardants added to them. Of course, special fire-retardants are 
also present in some of the polyurethane formulas utilized, e.g., 
chlorendic acid-based intermediates, antimony trioxide, bromine and 
phosphorus compounds. 
Various modifications may be made in the equipment. For example, the 
cylindrical drive rollers may be replaced by a plurality of thin wheels 
pressing the belts downwardly and various special shielding means may be 
employed to protect the photocell against any stray light sources on 
especially bright days. Machine sizes and automation and control means may 
be altered and construction materials may be changed, as from steel to 
aluminum or stainless steel. 
Utilizing the methods described, the controlled, even membrane-surfaced 
monolithic polymer foam of excellent uniformity and low heat conductivity 
and of good strength is laid down, which adheres firmly to the roof and to 
the membrane covering. No overspray problems are encountered and exposure 
of the operators to toxic fumes and sprays is minimized. The machine is 
capable of being operated by one man, rather than a team of men and the 
insulation laid down is of higher quality and is more rapidly and 
efficiently produced than by other known methods. 
The invention has been described with respect to illustrations and examples 
thereof but is not to be limited to these inasmuch as it will be evident 
that one of skill in the art, with the present description before him will 
be able to utilize substitutes and equivalents without departing from the 
spirit of the invention.