US3676170A - Method for spraying a high density insulating mat - Google Patents

Abstract

THE APPARATUS AND METHOD FOR APPLYING A HIGH DENSITY, FIBROUS INSULATING MAT SURFACE WHICH REQUIRES NO TAMPING. A BLOWER AND NOZZLE ARRANGEMENT TO MIX AND SPRAY THE FIBROUS MATERIAL IN AN EXTREMELY HIGH VELOCITY IMPACT STREAM.

D R A W I N G

Description

July 11, 1912 R. 1.. KEMPTHORNE 3,676,170

METHOD FOR SPRAYING A HIGH DENSITY INSULATING MAT Filed. March 30, 1970 3 Sheets-Sheet 1 RESTRICTED DRIFICE.

INVENTOR. RICHARD LEWIS KEMFTHDRNE 3 Sheets-Sheet 2 R. L. KEMPTHORNE m INVENTOR.

RICHARD LEWIEI KEMF'THDRNE METHOD FOR SPRAYING A HIGH DENSITY INSULATING MAT July 11, 1972 Filed March 30, 1970 July 11, 1972 R. KEMPTHORNE 3,676,170

METHOD FOR SPRAYING A HIGH DENSITY INSULATING MAT 3 Sheets-Sheet 5 Filed March 30, 1970 H E W k SWITCH TRAHE ama EIDLENDID EITEAM GENERATDR INVENTOR. l RICHARD LEWIS KEMPTHDRNE United States Patent O 3,676,170 METHOD FOR SPRAYING A HIGH DENSITY INSULATING MAT Richard Lewis Kempthorne, Miami, Fla., assignor to Sprayon Research Corporation, Fort Lauderdale, Fla. Continuation-impart of application Ser. No. 658,012, June 19, 1967. This application Mar. 30, 1970, Ser. No. 23,970

Int. Cl. B44c 1/08 U.S. Cl. 117-16 3 Claims ABSTRACT OF THE DISCLOSURE The apparatus and method for applying a high density, fibrous insulating mat surface which requires no tamping. A blower and nozzle arrangement to mix and spray the fibrous material in an extremely high velocity impact stream.

This application is a continuation-in-part of US. patent application No. 658,012, filed June 19, 1967, now abancloned.

BACKGROUND OF THE INVENTION This new product is the result of intensive research and development, using equipment and materials well known in various fields but which were never so combined to create an entirely new building material in the field of sprayed fibers.

All previous fibrous mats have been soft, with little internal bond and poor textures. The pneumatic pressure used before has been the sheath type or a positive pressure blower. The sheath type blower consists of a fan blade in a housing. The fiber goes through the casing and is in contact with the fan blade. Serious erosion occurs to the fan blade and casing. Such a blower would not produce snflicient pressure to have the necessary high velocity impact. Neither would the positive pressure blower in the manner in which it has previously been used.

Heretofore, sprayed fiber mats were blown on the theory that the fiber should be applied by a blower pressure only, suflicient to lightly float the material into place. As a result, a considerable amount of fiber never reached the ceiling, falling to the floor as waste. The mat so sprayed was so weak that it would not stay in place until tamped.

The greater density in this new product is made possible by the high velocity impact and the addition of dry steam.

All of the above difficulties are eliminated in the new process. The weight of the mat by the new process can be controlled from 8 to 30 lbs. per cu. ft. in a one-coat application and there are no Fall outs.

An inexpensive sprayed fireproof fiber ceiling applied to a smooth surface has never before been available, one that could compete with sprayed plaster or other materials. Plaster is hard and brittle and has very little resiliency. When it is applied to a surface having different characteristics of expansion and contraction, it tends to crack and peel, due to the change in temperature, such as the change of seasons.

Sprayed fibers heretofore could not be applied less than approximately because the fiber nodules were not broken up, which allowed the original surface being sprayed to be seen through the mat. In addition, tamping was necessary.

Now for the first time, a ceiling, hard, thin, /8", fireproof, good in appearance, having remarkable acoustical properties, is available at a cost of only a few cents per square foot. Such a product is unaffected by moisture, condensation or steam, or change in temperature. It has "ice sufficient thermal insulation value to eliminate condensation in most cases.

BRIEF DESCRIPTION OF THE INVENTION The high density, tough in texture, insulating mat is created by placing fibrous materials mixed with dry cementitious binders into a hopper where they are agitated and evenly fed into a stargate from which they are propelled by an air stream having a high velocity impact combined with dry steam. The material is transported by a flexible hose to a gunhead where it is wet, and then sprayed onto a surface.

It has been found that using the materials described, there is a threshold impact velocity above which the sprayed materials adhere to the receiving wall or ceiling surface having a density that requires no tamping.

The high velocity impact is further enhanced by restricting the gunhead opening. The body of the gunhead is like a Venturi tube. Not only does it increase the pressure but it prevents the water from running back and down into the blowing hose, causing a stoppage. The fiber is wet before it leaves the gunhead.

Formerly, when using the multiple nozzle gun (which wets the fiber in mid-air), the water ran back by gravitation and caused a Build up of fiber in the gunhead. The workman spraying had to use his fingers to clean out the Build up every half minute or so. If it were not done, the entire hose would become blocked. A half hours time could be lost in cleaning out the equipment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the hopper A, in which the fiber is placed. The fiber is metered evenly into a stargate B from which it is propelled pneumatically by a positive pressure blower D capable of creating a high velocity impact, and into a flexible hose C, and emerges from the Venturi-like gunhead E, being wet internally before it reaches the point of the gunhead exit.

FIG. 2 shows the multiple nozzle gunhead with a slightly restricted opening.

FIG. 3 illustrates the manner of the addition of the steam into the blowing hose, as described in the Kempthorne Pat. No. 3,012,732, dated Dec. 12, 1961, which is unsatisfactory.

FIG. 4 shows the manner in which the steam is admitted in a straight line to the elbow H.

FIG. 5 is a side view of the hopper, and FIG. 6 is an end view. FIG. 7 is a plane view of the mechanism from above and through the line 77 of the hopper. FIG. 8 is a schematic drawing, showing the solenoid controlling the admission of the steam into the air stream.

PREFERRED EMBODIMENT OF THE INVENTION The action of the hopper is described as follows: (FIG. 5). The fiber is placed in the top open end in the compartment Y. It is agitated by the slow-moving fingers N which prevent the bridging of the material. The fiber is then fed by the revolving auger screw M into the feed box I onto the carding brush Q. The carding brush Q can be either driven at high speed to better fi-berize the material or it can consist of rows of small rods welded to a common shaft. Either the carding brush or the rods welded to the shaft may be used to fiberize the material and break up the lumps so that it flows freely into the feed box I. The choice of using the carding brush or the rod type is determined in accordance with the type of job and the finish desired. The fiber then falls into the upper open compartment of the stargate B, which revolves until it reaches the bottom position. At that point, the air stream with the high velocity impact combined with the steam below the fiber from the lower compartment of the stargate into the hose C. The fiber is then propelled to the gunhead E, where it is wet and sprayed onto a surface.

FIG. 8 is a schematic drawing showing the steam generator having a pressure gauge, a relief valve, and a valve through which the amount of steam being used is controlled. An electric solenoid starts and stops the flow of steam. It is actuated by being connected across the line which supplies the current for the motor R driving the auger and agitator. It also runs the stargate. Two motors may be used, one to run the stargate and the other to rotate the screw auger M and agitators N. The steam is carried by the insulated hose to the two-way valve, the purpose of which is to clear out any condensation in the steam line (before starting). Dry steam only is used. The dry steam is fed by the removable nozzle '1 into the elbow H. The high velocity impact pneumatic pressure enters the elbow by the hose W. The combined steam pressure and air stream clear out the fiber from the bottom compartment of the stargate B and into the blowing hose C. It is wet by the gunhead E. As before stated, the gunhead E can be of the Venturi type (wetting the fiber before it leaves the gunhead), which is better, or the multiple nozzle type (which wets the fiber in midair) and spraying the fiber onto a surface where it is either left in the natural finish or tamped to a travertine texture.

FIG. 8 also shows the buck and boost transformer. By turning the handle and watching the voltmeter, the incoming line voltage can be adjusted either up or down to maintain the proper operating voltage. This improvement saves a lot of lost time on most construction jobs. Generally the line voltage is too low. The buck and boost transformer will raise the voltage within limits so that the entire operation continues smoothly. Adding a time clock connected across the line is also an improvement of value. It records the actual blowing time on any given day, as against the expensive down time which dissipates the profit.

Dry steam is admitted in a straight line at the elbow as the air stream enters the stargate. Several things are accomplished by this new improvement. The steam at 100 lbs. pressure (the pressure generally used), adds considerably to improve the high velocity impact. It clears out the fiber from the stargate. It stops the cloud of dust caused by the leakage of the sealing strips in the stargate. It also partially hydrates the dry binders in the fiber mix which makes a stronger mat.

The motor F of the stargate (see FIG. '6) has six compartments. The sealing strips K on each blade wear, allowing the air pressure to Blow back into the feed box I of the hopper A. The Blow back of the unwanted air in that direction even goes through the fiber in the hopper and causes a cloud of dust. The admission of dry steam at the elbow H does not eliminate the Blow back, but it does stop the obnoxious cloud of dust from filling the room. This works perfectly. The introduction of the steam into the hose, as in the Kempthorne Pat. No. 3,012,732, dated Dec. 12, 1961, is not satisfactory. The gooseneck L (FIG. 3) is too small, too weak to withstand the high pneumatic pressure and the flow of fiber. ilt bends out of position, causing a stoppage.

The introduction of dry steam at the elbow carrying the air stream is not limited to this patent application alone, but can be used in other sprayed fiber applications.

The new product is made of raw materials, the combined weight of which is even lighter than those used before, yet the mat produced is higher in density, tougher in texture, with a strong internal bond.

Mineral or rock wool by itself has never been a satisfactory material in the field because there is no internal bond or strength of mat. The use has been possible only by adding other supporting long-fibered materials such as asbestos, but even then the amount of mineral wool was limited.

Rock or mineral wool, asbestos and cementitious materials, applied by either the sheath-type blower or a rotary positive pressure blower, could only be sprayed to a thickness of about 1 /2" to 1%" before it would fall of its own weight. The surface was uneven and with many particles hanging down producing an altogether unacceptable finish. The surface had to be tamped or compressed into a mat of about one-half its former sprayed thickness. The fibers were then locked together for stability.

To obtain a greater thickness, the surface had to be rewet as the moisture had been squeezed from the surface of the mat by tamping. If the surface was not again wet with water, any added thickness will immediately peel off and fall. After again re-wetting, an additional 1%" to 1% was applied and tamped as before. A three-coat application was needed for anything over 1%" for a finished surface. To obtain a good two or three-coat application, the utmost in skill is required to prevent Fall outs. In order to fill in these annoying and expensive Fall outs, patience and experience is required. This trouble in application by former methods is because the mat is of low density and has little internal strength.

The weight of such a sprayed, untamped fiber mat is approximately /8 to 4 lb. per square foot at 1%" untamped thickness. The figures quoted are approximate and they will vary slightly with experience. Also, the production in square feet of completed work per day varies with the skill of the workman.

Water may drip through the mat Without damage. It is non-corrosive. Additives can be used to prevent rust or to make it a moisture barrier. Damaged spots can be hand repaired. The product is not subject to flaking. It has suflicient resiliency to be applied to a flexible surface (within limits). It will withstand vibration. It is especially adapted to marine construction. It has been wind tunnel tested. It is a fireproof material. It is of mineral composition, and therefore has a long life. It can be dusted but not hand-washed. It is not an outside all-weather finish.

It is no longer necessary to use (for strengthening purposes) long-fibered additives or to spray liquid adhesives along with the fiber.

The dry adhesive mixed with the mineral wool is dampened by the steam and the high impact velocity causes the fibers to be welded together in a tangled, compact mass. In pulling apart such a mat, long fibers hang together even better than when the asbestos was used.

When applying /3" to A" of the new material to a surface to which it would ordinarily not adhere (such as Teflon), a circular area about 24" in diameter was peeled off while still wet. The mat was so strong and tough that it could be waved through the air, which is certainly a striking demonstration of internal strength.

Up to this point, only mineral wool, with a small amount of additives, has been discussed as a suitable material. The reason for this is that mineral wool is an inexpensive and plentiful material. Other fibrous materials may also be used. 'Perlite and vermiculite may be mixed with mineral wool or other fibers, or other flaky materials.

Fair results may be obtained by using the conventional gunhead, which wets the materials in mid-air and which has no restricted opening. The results are not good. The wetting action also is not as eflicient. Also, the elimination of the steam cannot be considered as a way to avoid infringement.

Gunheads of the type which wet the material internally may be of several different designs. The water may be emitted from many small holes in an internal ring or rings. It may be from a chamber. The water may be atomized by air, or from a fan jet-type nozzle.

In the field of fireproofing, the difierence in density is most important. Fire tests have been made on deck and beam assemblies at recognized, qualified laboratories. In some cases, up to 3 of materials (having a low density of from 9 to 10 lbs. per cu. ft.) were needed to give a three hour fire rating, whereas even less than /2 of that thickness was needed if the sprayed mat was hand-tamped to a density of approximately 18 lb. per cu. ft. This new method produces the needed density with a one-coat application that requires no tamping.

Experience in many fire tests has shown that a higher density is needed to better prevent the flow of heat, but beyond a certain point, increasing the density causes the heat flow to increase, and the fireproofing qualities are thereby reduced.

All fire ratings on deck and beam assemblies must state the density in lbs. per cu. ft. of the protective materials used.

The cost of application is an important factor. In the past, one man is always needed to tamp the material; the elimination of one man per crew provides an important saving in competitive bidding.

The elimination of the tamping, because of the application using the high velocity impact, means in some cases cutting the labor costs of application in half. If an operator, standing on the floor with a firm footing and using the long pole gun is able to apply the material to a ceiling, having the proper density without tamping, the labor costs are halved. Without that advantage, scaffolding would have to be used which was the practice heretofore and laborious tamping was needed to lock the fibers together to provide the needed internal strength as well as density.

The positive pressure blower creates a pressure from /2 'pound per square inch up to 3 pounds, while the volume varies from 75 cubic feet per minute to 150 cubic feet per minute and requires from 3 HF. up to 5 H.P. The blower running at 900 r.p.m. and producing /2 pound pressure at 75 cubic feet in other words, doubling the speed to 1 800 produces the three pounds pressure and at 150 cubic feet requires a 5 RP. motor.

However, at the 1800 r.p.m. producing the three pound per square inch pressure and requiring a 5 HP. motor produces only a part (and rather a small part) of the high impact velocity. By holding the hand in front of the 2 /2" opening, no pain would be felt, but by restricting the opening, as described in the Venturi gunhead, the pressure is so increased that the hand can no longer be held in the air stream.

It is for the reasons detailed in the immediately above paragraph that the high velocity impact application, accompanied by a carding brush action produces an altogether new product, one never before seen in the business of sprayed insulation.

The fibers before used have varying amounts of rock wool and asbestos. The real purpose of the asbestos has been to furnish a bonding strength needed in the internal fiber mat.

The rock wool in itself did not have enough cohesion of the fibers to hold the mat together but by increasing the velocity and the capacity of the carding brush action, the mineral wool is so shredded that the amount of asbestos can be greatly reduced or even totally eliminated. A handful of mineral wool after being so carded is an entirely different material than in its original state and before the carding action. The high impact velocity welds these mineral wool fibers together with the adhesives and additives which is a product really astounding because of its superior characteristics.

It can be shown that a volume flow of 75 cubic feet per minute of surfacing material using a two and one- 6 half inch nozzle will result in an impact velocity of approximately 2,200 feet per minute, and with a one inch nozzle 13,700 feet per minute. It has been found that by using the materials discussed above in an impact spray above 4,000 feet per minute that the resulting impact mixture requires no tamping. Such a flow may be achieved with a volume flow of cubic feet per minute with a 1% inch nozzle. The higher the impact velocity, the better the resultant mixture.

The instant invention has been shown and described herein in what is considered to be the most practical and preferred embodiment. It is recognized, however, that departures may be made therefrom within the scope of the invention and that obvious modifications will occur to a person skilled in the art.

What I claim is:

1. A method of making a high-density insulating mat, strong in texture, comprising the steps of:

(a) mixing fibrous materials and additives in a hopper;

(b) accelerating said fibrous mixture from said hopper in a high velocity impact stream with high velocity air through a conduit;

(c) injecting water into said accelerated mixture just prior to its ejection from said conduit; and

(d) ejecting said accelerated mixture above a velocity of 4,000 feet per minute from said conduit onto a surface, whereby said surface is so uniform in texture and density that no tamping is required.

2. The method as in claim 1, including the step of:

(e) directing additional accelerated mixture from said conduit onto the mixture on the surface, the finish being an acceptable travertine requiring no additional tamping.

3. A method of spraying a fiber mat that is tough in texture, fireproof, and high in density comprising the steps of:

(a) combining non-asbestos fibers with cementitious binders in a hopper;

(b) feeding said combined materials into a stargate;

(c) propelling said combined materials by a positive pressure blower with high velocity impact air through a conduit;

(d) wetting said high velocity impact material stream;

and

(e) ejecting at above four thousand feet per minute said high velocity impact material onto a surface, with a pebbly finish whereby said finish requires no tamping.

References Cited UNITED STATES PATENTS 3,012,732 12/1961 Kempthorne 239-300 3,096,968 7/ 1963 Kempthorne 239-428 X 3,023,967 3/1962 Schlemmer 239142X 1,139,091 5/1'915 Weber 117-27 UX 3,240,533 3/ 1966 Mommsen 239-336X 2,696,353 12/1954 Vessels 1l7-105.5 X

FOREIGN PATENTS 7 525,125 5/1956 Canada 117105.5

ALFRED L. LEAVITT, Primary Examiner J. H. NEWSOME, Assistant Examiner US. Cl. X.R.

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