US2753598A - Method for forming and collecting fibers - Google Patents

Description

July 1956 G. SLAYTER 2,753,598

METHOD FOR FORMING AND COLLECTING FIBERS Filed Jan. 4, 1954 2 Sheets-Sheet 1 TTORNEYS G.SLAYTER July 10, 1956 2 Sheets Filed 45 I I: I

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United States Patent METHOD FOR FORMING AND COLLECTING FIBERS Games Slayter, Newark, Ohio, assignor to Owens-Corning Fiberglas Corporation, a corporation of Delaware Application January 4, 1954, Serial No. 401,856 3 Claims. (Cl. 18-473) This invention relates to a method and apparatus for forming and collecting fibers and more especially to the formation and collection of fibers attenuated from heatsoftenable mineral materials such as glass by a gaseous blast and collecting the attenuated fibers in mat formation in a zone substantially unaffected by the velocity of the gases of the blast and its induced air stream.

In the manufacture of fibers from glass or other heatsoftenable mineral materials, it has been a practice to utilize intensely hot, high velocity gaseous blasts as an attenuating means for forming the fibers, the blast being provided by continuously burning a combustible mixture in a burner chamber or confined zone and discharging the burned gases or products of combustion through a restricted orifice at high velocities. Burners of this character are usually employed in groups, and the fiberforming material is continuously delivered into the gaseous blasts adjacent the orifices in the form of a series of groups of primary filaments or elongated bodies of glass. The advancing extremities are continuously softened by the intense heat of the burned gases and the softened material is drawn out or attenuated into fibers by the velocity of the gases of the blasts.

The burners are preferably disposed to produce substantially horizontal blasts, and the fiber-forming material is moved in a substantially vertical direction into the blasts. The gases of the blasts and fibers entrained therein are discharged into an enclosure or hood in which is disposed a movable foraminous conveyor upon which the fibers are collected. The enclosure or hood is of rectangular cross section and 75 feet or more in length. The

spent gases of the blasts and the induced air streams may be discharged through the mat and conveyor by suction effective beneath the conveyor.

In this method of fiber formation and collection, the high velocity gaseous blasts create or establish secondary blasts of induced air which are uncontrolled and which materially impair the collection of the fibers in forming a mat. In usual commercial operations a binder in liquid form is sprayed or otherwise delivered onto the fibers. The presence of binder on the fibers renders them tacky, and there is a tendency for some of the fibers entrained in the secondary blasts or induced air streams to be carried into contact with the walls of the enclosure or hood where they collect or accumulate to form nodules, tufts, plumes or flake-like gatherings of fibers which eventually fall from the walls of the enclosure or hood as inclusions in the mat. Such inclusions must be removed by manual means from the surface of the mat. The gases of the blasts and more especially the secondary air blasts formed by the induced air stream cause the fibers during their flight from the burner and deposition to be agglomerated and drawn into wads and hanks or similarly shaped gatherings which result in a mat of nonuniform thickness and erratic structure. Mechanical and thermal properties of a mat with such nonuniform structure are adversely alfected.

It has been found that an intensely hot blast of burned gases discharged from a confined zone through a re stricted orifice has certain characteristics which become critical factors in the utilization of the blast for attenuating glass to fibers. A blast of burned gases discharged from a combustion chamber is usually of a temperature of 3000 F. or more, a temperature well above the softening point of glass. As the gases travel away from the burner orifice, the blast temperature decreases, and it is found that a distance of about four feet from the burner orifice is substantially the maximum distance or range in which the glass may still be fused and the fusion range determines the maximum distance within which the material is soft and attenuable to fine fibers by the velocity of the blast. The rapidly moving gases of the blast set up or establish a secondary blast or induced air stream which moves along the boundaries of the gases forming the primary blast and eventually the secondary blast and gases of the primary blast adjacent thereto initiate or form a zone of turbulence which changes or modifies the orientation and degree of agglomeration of the attenuated fibers entrained in the blast. It is found that this turbulence at the boundaries of the primary blast begins to form at a distance about six feet from the burner orifice of the coventional type of internal-combustion burner.

The present invention embraces a method and apparatus for controlling the gaseous blast and induced air stream or secondary blast in a manner whereby the fibers may be continuously filtered out or removed from the blast and conveyed to a substantially quiescent zone where they may be collected in mat formation unaffected by the attenuating blast or the induced air stream.

An object of the invention is the provision of a method of controlling the secondary blast or induced air stream established by a primary blast in a manner to divert the secondary blast away from the zone of collection of the fibers.

Another object of the invention is the provision of a method of removing attenuated glass fibers: from a gaseous blast at a zone disposed between the fusion zone of the blast and the region in which the secondary blast or -induced air stream sets up a turbulent zone along the blast so as not to appreciably impair or modify the natural orientation or arrangement of the fibers established during their formation in the blast.

A further object is the provision of apparatus for attenuating bodies of heat-softenable material to fibers through the utilization ofa high velocity gaseous blast and continuously removing the fibers from the blast on a rapidly moving surface adapted to convey the fibers to a conveyor for collection into a mat, the apparatus including means for conducting the spent gases of the blast and the blast-induced air stream away from the fiber collection zone to facilitate the formation of a mat having a substantially smooth surface and of uniform thickness throughout its area.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, tovarious details of construction and to combinations of parts, elements per se, and to economics of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

Figure 1 isan elevational view showing a form of apparatus for carrying out the method of the invention;

Figure 2 is a top plan view of a portion of the apparatus shown in Figure 1, part of which is shown in section for purposes of illustration;

Figure 3 is a sectional view taken substantially on the line 33 of Figure 2, and Y Figure 4 is a longitudinal sectional view of a combustion burner forming a part of-the fiber-forming arrangement.

Referring to the drawings in detail there is illustrated in Figure 1 a furnace or unit for melting glass or other heat sofitenable,fiber-forming materials. Thefuirnace is equippedzwith a:forehearthconstruction 12 which is provided with .a pluralityof feeders or bushings, one. of which istshown at 14.. Eachofthefeeders. 14 is.pro vided with .a-plurality of orifices. or openingsina bottom wall thereof through which flow fine streams S of 1 glass or other material for forming the'primary filaments F.

.The. streams S are continuously drawn or attenuated to primary filaments b-ymeansofsets of feed rolls 18 which engage the solidified filaments to draw the streams to -the desired sizeof filament and advancethe filaments at a predetermined rate. The primary-filaments are .di rectedt-hrough a suitableguide-means 2%, the extremities ofthe-filamen-ts of each group beingdirectedby-the guide means into a blast B emanating from each of the burners :22.

A battery or group of five burners is illustrated in Figure 2' for producing five individual blasts, each adapted to attenuate a groupof primary filaments F tofine fibers. -It is-to be understood that any number of burnersmay be employed, depending upon thequantity of material to be attenuated to fibers in a given period of time and the width oft-he fibrousmat to be formed from the fibers.

The number of primary filaments delivered into each blast may vary, and it is found that from 30 to oil-filaments should be projected into each blast. Each guide member 20 is provided with a series ofparallel grooves (not shown) for-properly spacing theiindividual filaments of each group as they are projected into the blast B in order to avoid adjacent filaments becoming fused together, a condition which would interfere with proper attenuation of the filarnentsto fibers.

A form of internal-combustion burneru-tilized for pro- -d-uci-ng an intensely hot, high velocity blast is shown in Figure 4'. The burner consists of a metal shell in which is-disposed refractory linings26 and 27 the inner wall of the inner lining 27 defining a combustion chamher or confined zone 30 in which a combustible mixture 'is adapted to be burned. The forward or nose end of the burner is provided with a refractory member 32 having a hollow interior, the walls of which join the interior wall of the lining 27. The interior walls of member 3 2 are arranged in converging relation toward thenose end of the burner 'to form a restricted orifice 35 of generally rectangular shape from whichthe burned gases or products of combustion or burned gases from the chamber 30 are discharged as a high velocity blast.

The rear portion of the burner is provided with a wall or' screen 37' which is formed at its central zone with a plurality of small passages 39' which convey a combustible mixture from a supply to the confined zone or chamber 30; Secured to the rear end of the burner by means of bolts 41 is a member 42 which has ahollow interior providing the mixture supply chamber or mania fold- 40. The member 42 is formed with a bored and threaded boss portion 44 to receive a combustible mix ture supply pipe 45 shown in Figures '1 '2' and 4.

As shown in Figure 2, a supply pipe 45pis' provided for each burner. Associated with each pipe. 45 is a valve 46 for regulating the amount of combustible mixture delivered into each individual burner from a manifold or tube 4'8. connected with a fueland-air supply and adapted to convey the mixture to eachofthe burners- 221.

A combustible mixturev comprising agaseous fuel such .asnatural or artificial gas, propane, imethaneor the like,

mixed with the requisite amountof air to support compl t com u is pp d to th ma t fO und r a comparatively low pressure of fromone to pounds per square inch- The. mixture firomthe manifoldis .con-

veyed through the passages 39in the: scneenl-or wall '37",

and the mixture is burned within the confined chamber or zone 30 of each. burner.

As the burning takes place in a confined zone, the refractory lining 27 becomes very hot and usually is heated to incandescence, the burning gases undergoing great expansion due to combustion and radiation of heat energy from the hot chamber walls so that the mixture is substantially completely burned within the chamber and the burned gases or products of combustion discharged at high velocity through the restricted orifice 35. The primary filaments F of glass or other material are delivered into the blasts B adjacent the orifices 35, the extremities of the advancing filaments being softened by the heat of the blasts and the softened material attenuated to fibers byv the force of the blasts.

The high velocity blasts B set up or establish secondary high velocity blasts of induced air which travel along the boundary layers of the gaseous attenuating blasts B. ,Heretofore, the high velocity primary blasts B and the secondary blasts of induced air have impaired satisfactory collection of the attenuated fibers due to the lack of control of the gases of both the primary and secondary blasts.

In the present arrangement, a method and means for filtering or removing the attenuated fibers from the zone of the blasts and continuously conducting or conveying the attenuated fibers to a quiescent zone make possible the collection or deposition of thefi-bers in a satisfactory mat formation. Means is also provided for controlling or disposing of the gases of the blasts so asto-preserve as far as possible the orientation of the fibers existent in the blasts to secure a mat having improved physical characteristics of strength, insulating value and appeara-nce.

As particularly shown in Figures 1 and 2, a rotatable member in the form of a drum or cylinder 50 having a forarninous or perforated surface 52 is disposed inthe path of the primary and secondary blasts in a position whereby the newly formed, attenuated fibers entrained in the blasts are filtered out of the blasts and collected upon the foraminous exterior surface of the drum, and the gases of the blasts are projected through theperforations' inthe surface 52 intothe interior of the drum for disposition in a manner hereinafter explained. The drum is suitably journaled for rotation and is provided at its ends with members or plates 54 and 55, respectively. A relatively stationary tube or hollow shaft 56 extends through the end plate 54 and an antifriction bearing means 531 such as a roller bearing, is interposed between the hollow shaft 56 and the end plate 54 to provide for rotation of the drumrelative to the shaft 56.

The shaft 56 is supported on a suitable support or standard 60 and is held in fixed relation on the standard by means of a cap member 62, the cap member being removed in Figure 2' of the drawings for purposes of illustration. The drum maybe driven by suitable means. For example, a sprocket 64, secured to a hub portion of the end plate 54, is connected by means of a chain with a sprocket 66 mounted upon a shaft 67 driven by an electrically energizable motor 68 or other suitable source of power.

Disposed within the drum 50 is a bafflejarrangement for intercepting the gases projected through the foraminous surface 52' of the drum, the bafil'e' arrangement function'- ing in conjunction with means for conveying the gases to a region remote from the fiber-collecting zone. Disposed within and adjacent the respective ends of. the drum. 50 are stationary end plates, members or baflles 7.0 and. 71 shown in Figure 2. The baffie 7-0 is supported by a hub member 73 mounted. .or secured upon the hollow shaft 56 and serving to support the plate 74). Thepl ate 71; at the opposite end of the drum is supported by the: extremity of a stationary metal ductor tube '75 which is. centrally arranged with respect to the axis of rotation of the drum and serves to convey gases away from the interior of the drum.

The end plates 70 and 71 are connected to a stationary baflle plate 77 extending longitudinally of the drum and shaped as illustrated in broken lines in Figure l, the plates 70 and 71 and baflle member 77 defining a gas-receiving chamber within the drum. As exemplified in Figure l, the cylindrical, foraminous surface area of the drum is exposed to the atmosphere for a circumferential distance preferably greater than l80", and this peripheral area subtended by the baflie 77 is subjected to suction effective through duct 75.

Surrounding the gas-exhausting duct 75 adjacent the end member 55 of the drum is a relatively stationary ring 80 having its exterior diameter establishing a close, yet running, fit with the hub portion 82 of the end member 55. The hub portion 82 is formed with a circumferential recess 84 forming a raceway to receive supporting disks or rollers 86 journally supported on pins or stub shafts 87 carried by supporting member 88 in the manner shown in Figure 3. The drum is thus supported for rotation upon bearings 58 disposed at the lefthand end of the drum as shown in Figure 2 and upon the supporting rollers 86 disposed at the righthand end of the drum.

The gas exhaust duct 75 is of comparatively large diameter in order to effectively withdraw and carry away the large amount of spent gases of the attenuating blasts and the induced air of the secondary blasts. The duct 75 is connected with a suitable, large-capacity exhaust or suction blower contained within a casing 90 illustrated diagrammatically in Figure 2.

Due to the suction or subatmospheric pressure established in the duct 75, effective suction is existent at the periphery 52 of the drum 50 throughout its uppermost zone above the baffle plate 77 to hold the fibers filtered out of the blasts to the periphery of the drum until the fibers on the drum reach the limit of effective suction at the zone 92 determined by the relative position of the bafile 77. The fibers are removed from the surface of the drum at the zone 92 and are collected in a suitable manner, for example, on a movable support or conveyor, to form a mat of desired thickness.

To accomplish this purpose, an endless conveyor 95 is supported upon a plurality of rollers 96, and the upper flight 97 of the conveyor is moved in a righthand direction as viewed in Figure l and is disposed so as to receive fibers discharged from the periphery of the drum 50. The conveyor 95 is moved by suitable motive means (not shown) connected with one of the rollers 96. Disposed beneath the upper flight 97 of the conveyor at the fiber collection or deposition zone is a suction chamber 99 connected by a tube or duct 100 with a suitable source of suction (not shown) to establish subatmospheric pressure at the fiber deposition zone of the conveyor to hold the fibers to the conveyor.

Means is provided for effectively removing or stripping the fibers from the surface 52 of the drum 50 at the zone 92. To accomplish this purpose, there is disposed beneath the baffle plate 77 a pipe or tube 102 which extends longi" tudinally of the drum as shown in Figure 2. The tube or pipe 102 is provided with a plurality of spaced nozzles 103 adapted to discharge jets or streams of compressed air or other fluid outwardly through the foraminous surface of the drum, the streams of air engaging and stripping or discharging the fibers from the drum surface at the zone 92. It is preferable to apply a liquid binder to the fibers as they move downwardly onto upper flight 97 of conveyor 95. A series of binder applicators or nozzles 105 may be disposed in the position shown in Figures 1 and 2, spaced longitudinally of the drum and receiving binder from a manifold 106 in order to coat the fibers with a binder as they are deposited or collected upon the conveyor flight 97.

A tube or pipe 107 is connected with the air distribution pipe 102 shown in Figure 2, the pipe 107 extending up- 6 wardly through an opening 108 in the bafile plate 77. The pipe 107 is connected to the end of the stationary hollow shaft 56 projecting into the interior of the: drum 50. The end of the stationary shaft 56 at the exterior of the support 60 is connected by means of a pipe 110 with the source of the supply of compressed air (not shown). The pressure of the air streams or jets which are extruded through the stripper nozzles 103 may be controlled by a valve or regulating means 112 associated with the air supply pipe 110.

The general operation and method as carried out by the apparatus are as follows. Molten glass or other heatsoftenable, fiber-forming material is delivered from the forehearth 12 through orifices in the feeders 14 in the form of a plurality of groups of streams S which form primary filaments F. The primary filaments are attenuated or formed from the glass streams by means of the feed rolls 18, the primary filaments F being preferably between .010 and .030 in diameter. The primary filaments F are fed continuously through the guide means 20, and the extremities of the advancing filaments are projected into the blasts B emanating from the burners 22. The intensely hot, burned gases from the blasts B continuously soften the extremities of the primary filaments F, and the softened material is drawn or attenuated by the blasts into very fine fibers of one to six microns in diameter. The attenuated fibers entrained in the blasts are intercepted by and collected upon the foraminous surface 52 of the drum 50. The suction set up in the zone within the drum above the baflie plate 77 through the medium of the suction blower contained in the housing causes the spent gases of the blasts and induced air of the secondary blasts to be continuously withdrawn from the interior of the drum through the duct or tube 75. The suction impressed or existent within the drum is effective to cause the fibers on the foraminous surface 52 to be held thereto during rotation of the drum until the fibers reach zone 92 identified in Figure 1. The drum 50 is rotated at a substantial speed so that its peripheral moves at 500 to 1500 linear feet or more per minute so that the fibers are continuously and rapidly moved away from the zone of impingement of the blasts upon the drum periphery. By removing the fibers rapidly from the zone of the blasts, the gases of the blasts move comparatively freely through the foraminous surface 52 as the fibers do not pile up to set up resistance to movement of the gases of the blasts and the induced air through the drum periphery. Through this arrangement, the very thin accumulation of fibers on the drum .50 is moved to the zone 92 which is a comparatively quiescent region because the rapidly moving, spent gases and induced air have been withdrawn in a manner which does not materially impair the orientation of the fibers on the drum. At the zone 92 the air jets from the nozzles 103 continuously strip or remove the fibers from the surface of the 0 drum; and by reason of the relatively undisturbed ambient atmosphere in this zone, the fibers move downwardly onto the flight 97 of the conveyor 95. During the downward movement of the fibers from the zone 92 onto the flight 97 of the conveyor, liquid binder may be applied from the applicators 105 to coat the fibers thoroughly as they move to the collection zone. The conveyor is arranged to be driven at varying speeds and is moved at a comparatively slow linear rate, depending upon the desired thickness of the mat to be formed on the conveyor. As the deposition of the fibers on the flight 97 of the conveyor is in a relatively quiescent zone, the fibers may be accumulated into a mat of uniform thickness throughout the surface area of the conveyor without the forma tion of rufiles or irregularities in the surface region of the fibrous mat. Furthermore, this arrangement eliminates the formation of tufts or plumes which may fall periodically from a hood surface onto the mat, necessitat' ing manual removal of the same from the mat. The arrangement of'the drum 50 and mat-collecting conveyor 95 may be operated in an open room or, desired, in a 7 hood or chamber, indicated diagrammatically in broken lines at 120.

The distance of the peripheral zone 52 of the drum engaged by the blasts from the source of the blasts at the burners 22 is of somewhat critical character in obtaining completely attenuated fibers and securing the advantage of the natural orientation of the fibers establishedn'n the blast. It is highly desirable to remove the entrained fibers from the blasts at the zone between the region in the blasts at which fusion ceases and before the induced air streams result in turbulence at the boundary layer of the blasts. The normal attenuating range of blasts from burners of conventional type and size has been found to terminate approximately four feet from the burners which is the region of the blasts in which their temperatures fall below the softening point of glass, and thus attenuation does not take place at a greater distance from the burner. It has also been determined that at a distance approximately six feet from the burners the turbulence in the induced air streams increases in violence soas to impair the natural rectilinear orientation of the fibers entrained in the blasts. Therefore, it is highly desirable to dispose the drum with respect to the burners so that the zone of the periphery of the drum at which the fibers are withdrawn from or filtered out of the blasts is at a distance of from four to six feet from the sources of the blasts, viz, the orifices of burners 22. Through this particular positioning of the fiber-collecting drum surface with respect to the burners, the fibers are collected after attenuation is completed and before turbulence of the induced air streams distorts or materially modifies the orientation of the fibers in the blasts.

Thus, through the utilization of the novel method of fiber formation and collection of the fibers and subsequent deposition of the fibers in a mat formation in a relatively quiescent zone, the resulting mat is of uniform thickness and wrinkles and irregularities in the mat surface are avoided. It is to be understood that the method has utility wherein blasts of steam or compressed air are employed in lieu of intensely hot blasts for converting molten streams of glass or other molten material to fibers as the spent steam or air of the blasts may be projected through the foraminous drum surface and controlled or disposed of by the suction means effective in the baffied interior zone of the drum. Fibers so formed are not as fine as those attenuated by intensely hot blasts, but such fibers may be collected or deposited in mat formation in the quiescent region out of the zone of influence of the attenuating blasts and the induced air streams.

it is apparent that, within the scope of the invention, modifications and dilferent arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

1 claim:

1. A method of attenuating and collecting fibers formed from heat-softenable mineral material including delivering mineral material into a high velocity unconfinedgaseous blast of a temperature above the softening temperature of the material, attenuating the material to fibers by the velocity of the blast, projecting the blast and fibers entrained therein in a median path passing substantially through the axis ofa cylindrical foraminous surface, the force of the blast being sufiicient to convey the fibers to the foraminous surface, establishing a zone of reduced pressure adjacent the foraminous surface for conveying the gases of the blast and the air stream induced by the velocity of the blast away from the surface, rotating the surface at a comparatively rapid rate, and continuously collecting the fibers out of the blast onto the rotating surface at the zone of reduced pressure.

2. A method of attenuating and collecting fibers formed from heat-softenable mineral material including delivering mineral materiai into a high velocity gaseous blast of a temperature above the softening temperature of the material, attenuating the material to fibers by the velocity of the blast, pro ecting the blast and fibers entrained therein in a median path passing substantially through the axis of a cylindrical forarninous surface, the force of the blast being sufficient to convey the fibers to the foraminous surface, establishing a zone of reduced pressure adjacent the foraminous surface for conveying the gases of the blast and the air stream induced by the velocity of the blast away from the surface, rotating the surface at a comparatively rapid rate, and continuously collecting the fibers out of theblast onto the rotating surface between the region in the blast at which attenuation ceases and before the induced air stream sets up turbulence at the boundary layer of the blast.

3. A method of attenuating and collecting fibers formed from heat-softenable mineral material including delivering mineral material into a high velocity gaseous blast of a temperature above the softening temperature .of the material, attenuating the material to fibers by the velocity of the blast, projecting the blast and fibers entrained therein in a median path passing substantially through the axis of a cylindrical foraminous surface, the force of'the blast being sufficient to convey the fibers to the foramin'o'us surface, establishing a zone of reduced pressure adjacent the foraminous surface for conveying the gases of the blast and the air stream induced by the velocity of the blast away from the surface, rotating the surface at a comparatively rapid rate and continuously collecting the fibers out of the blast onto the rotating surface at a region in the blast of from four to six feet from the source of the blast.

References Cited in the file of this patent UNITED STATES PATENTS 1,765,025 Miller June 17, 1930 2,188,373 Pearce Jan. 30, 1940 2,450,914 Powell Oct. 12, 1948 2,450,916 Coss et al Oct. 12, 1948 2,489,243 Stalego Nov. 22, 1949

Claims (1)

1. A METHOD OF ATTENUATING AND COLLECTING FIBERS FORMED FROM HEAT-SOFTENABLE MINERAL MATERIAL INCLUDING DELIVERING MINERAL MATERIAL INTO A HIGH VELOCITY UNCONFINED GASEOUS BLAST OF A TEMPERATURE ABOVE THE SOFTENING TEMPERATURE OF THE MATERIAL, ATENUATING THE MATERIAL TO FIBERS BY THE VELOCITY OF THE BLAST, PROJECTING THE BLAST AND FIBERS ENTRAINED THEREIN IN A MEDIA PATH PASSING SUBSTANTIALLY THROUGH THE AXIS OF A CYLINDRICAL FORAMINOUS SURFACE, THE FORCE OF THE BLAST BEING SUFFICIENT TO CONVEY THE FIBERS TO THE FORAMINOUS SURFACE, ESTABLISHING A ZONE OF REDUCED PRESSURE ADJACENT THE FORAMINOUS SURFACE FOR CONVEYING THE GASES OF THE BLAST AND THE AIR STREAM INDUCED BY THE VELOCITY OF THE BLAST AWAY FROM THE SURFACE, ROTATING THE SURFACE AT A COMPARATIVELY RAPID RATE, AND CONTINUOUSLY COLLECTING THE FIBERS OUT OF THE BLAST ONTO THE ROTATING SURFACE AT THE ZONE OF REDUCED PRESSURE.

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