US2439602A

US2439602A - Insulating confined spaces

Info

Publication number: US2439602A
Application number: US477753A
Authority: US
Inventors: Clark C Heritage
Original assignee: Wood Conversion Co
Current assignee: Wood Conversion Co
Priority date: 1943-03-02
Filing date: 1943-03-02
Publication date: 1948-04-13
Anticipated expiration: 1965-04-13

Description

April 1948. c. c. HERITAGE 2,439,602

INSULATING CONFINED SPACES Filed March 2, 1943' :s Sheets-Sheet 1 I v 4/ fwz/emor Ufa 2% Cf reaye .22 iffarleqy c. c. HERITAGE INSULATING, CONFINED SPACES Apr-H13, 1948.

Filed March 2, 1943 3 ShetS-Sheet 2 lfforizey April 13, 1948. 9c. 0. HERITAGE 2,439,602

- INSULATING CONFINED SPAQES Filed March 2; 1945, .3 Sheets-Sheet 3 ffar 674752 7- gage Patented Apr. 13, 1948 Clark 0. Heritage, Cloquet,,.Minn.,, assignor to Wood Conversion Company, Cloquet"; Minn, a:

corporation ofDelaware Application-March 2, 1943, seriatNm amass Claims; (01. -101) The present inventionrelatesto the placement or particles of thermal insulating; material to build up a thermally insulatingintegrated mass of such material ina confined-space. In particular it relates to carrying the material in agaseousyeh'icle (hereinafter referred, to again); to .a deposited growing mass of suchparticles formed by deposition of particles from the vehicle.

plates completely confining aspaceto be so. filled withinsulation material, whereby to define the formof the mass to be produced, Thespacelmay be provided substantially completely by-or within existing articles. Howevenras requiredlor desired for/the purposes of the invention, the spacelto be filled is completely defined by bounding facial Walls having essentially some filtering area for exhausting the gas in which particles of' themsulating material are introduced, and havingessentially in the arealof the confining. Walls, one or more inlet areas for introducing the gas containing the particles, eachsuch inlet area being essentially in and a fraction of aconiiningwall In general aspect the invention contem- 1 or face in amanner analogous to the relation mits-the form ofthe space to be complex, or

angulanand not limited to. panel-form spaces. Thus, the vehicular stream of gas is introduced at aldifierential pressure, relative to the pressures at inlet area and at filtering area, and at such a velocity that the particles suspended in the gas are carried with turbulence insidethe space to all portions ofthe-space remote from inlet area;

and-that the differential pressure. packs the deposited mass to a consolidated body filling the spacewhile saidpressure of the gas streamis maintained to and-,if desired, even after the complete filling of the space.

The inventionis applicable in many fields, for examplain packing .fiber or other insulatinglmaterial into carboys to protect-and insulate the fiaks of. liquid t e W W its I Presently preferred use is in insulating the doors and cabinets of refrigerators, such as are used in homes.

In the, field of artificial refrigeration, high standards for insulation inl domestic andother refrigerators havedevelopedinorder to minimize heat'vlos s heat loss addsito the cost ofToperationt, Considerable difficulty has been encountered in the commerciall development: of refrigerator insulation in parallel with thedevelopment of domestic artificial refrigeration. Along with standards and .for low heat a loss, low cost oi insulating material and of insulating proc ass-are important, as-are uniformity in. each cabinet andl from. cabinet to cabinet in apmdnctmnimei a. a

In addition, there. is. the .problem of permahence, injlfwhich' 5 resistance I meani of packed bulk insulation is most important. Suchiresistance can be attainedhbyl increasing the density or" packing; with which heat? leak or heat. conductance increases asaa' generalrulainrthe, range encountered refrigerators. It is, therefore,

i'rnportantlto-minimize" density; consistently with acceptable -resi'stance. to settling and acceptable insulating value. All these factors leadltoaneed forlalprocesswhichis subject to control for meet- In. the prior. art there. has been no low-cost process for packing a specified'material uniformly and integrally intola cabinet, and uniformly from cabinetjt'o cabinetiinlaproductionline,a The present inventl'oinl provideslsucha process, and so usedfit giyes'reproduciblelresults with any reproducible material; Vegetable fibers such as from Wood may readily be produced from timeto time with reproducible properties within given specifications, andv withlsuchi material and with" the present. invention a low-cost process for uniformly, and insulating spaces, such as thoseinlreii'i-gerators; becomes available to the manufacturers refrigerators. Reference is made to my. copending application Serial No; 33fiA95jlfiledsMay 22,- l940',,now Patent No.v2',3 25,- 055, issuediJuly. 7," .1943; describing reproducible fibers whichgarea useful as. particles for practice of. the rp resentilihyentionn a The; present-application. is one of a series of mylcofiled. applicatibnslserial. Nosi47'7 751; 477-,- 7523. 4717:7531 4W;7.54;and 477,7,55; each one of the series being, directed. generically and specifically to a distincttspecies disclosedlin my said original aDDlicatiomSerialNb. 294L212;

It; isobiectot the; present invention to insulateinteriorwa-llsr ta-bodyproviding; an opent'ibat'w n ng the space to be insulated in part by meanstotaremoyable :fixturecontaining either one or both of inlet area and filtering area, and

tween the said dummy and the cabinet, then re-' moving the fixture and replacing it with the food 1' compartment.

Various other and ancillary objectsandadvan tages of the invention will appear from the fol-'- lowing description and explanation of the invention given with reference to the accompanying drawings in which:

Fig. 1 represents in perspective half of a refrigerator cabinet and aboveit in perspective half of a food compartment in position to be dropped into place in the cabinet; j

Fig. 2 represents in two parts a dummy for the food compartment, as a box-like fixture and a pipe system which belongs Within the'said fixture, the base being shown separated for convenience in illustration; 1 t I Fig. 3, represents the type of blower and feeding means thereforwhich is used for connection to the fixture ofFig.2;' J

Fig. 4 represents amodified fixture'as a dummy food compartment, having but one inlet conduit and having differently arranged filtering areas, one wall of the fixture being shown rectified to the plane of the bottom merely to faoilitate'the illus- Fig. 5 represents in perspective a'p'ortion of the refrigerator cabinet of Fig. l filled with insulating fiber by use of the fixture of Fig. 4; i

Fig, 6 is a fragmentary view in cross-section taken on the line 6--6 'of,Fig 4'and Fig: 5, when the fixture of Fig. 4 is in operatingposition within the cabinet;

Fig. 7 is a view in perspective and vertical cross- 4 food compartment of a refrigerating unit. One of the said openings to the space is used for introducing the gas, while the other is blocked oil. The open space at the door opening between the cabinet and the food compartment, where breaker-strip material is located in the completed refrigerator, is closed by a fixture or closure provided with filtering area, and preferably including also some imper forate area. Thus, the gas introduced passes through the gas-filtering body of insulating material built up in the space. Then the fixture is removed, and breaker strip used to close the gap. The space between the openings for the unit thus has insulation, which may be disturbed as necessary in making connections when installing the refrigerating unit.

section of an inverted carboy casing' with its with insulating material, after removal of the fixture, and after replacing the fixture by the bottle. j In my earlier parent application Serial No. 294,212, the process is "described generically and specifically with respect to various forms of the space to be filled, and various types of space-confining walls, and removable fixtures, having particular reference to variations in the process for insulating domestic type refrigerators. I These variations include filling-a refrigerator in which the food compartment is already mounted, and also in which the food compartment is not mounted. In the latter case, a fixture in-the form of a dummy for the food compartment is employed, and the fixture is used to provide filtering area, and may be used to provide inlet area. The process is flexible for accommodating it to various types of refrigerators, as well as various types of spaces not necessarily those of refrigerators. In

the aid earlier application, there is claimed'spe- It is also set forth that the stream is intro-. duced at a differential pressure between inlet and filter areas. This may be effected by having atmospheric pressure at either the inlet area, or at the filtering area. The latteris preferred for many practical and mechanical reasons. i

In the present application it i likewise intended that thepressureibe a difierential one, but to simplify the description and the illustration, only the preferred one of super-atmospheric pressure at inlet area is specifically described and illustrated without intention to limit the invention thereto. Q

After the introduction of the insulating ma terial into the space to be insulated, especially in a refrigerator, there are numerous mechanical operations which may be necessary to complete the article for use or sale. However, theseeform no essential part of the invention, and detailed description and illustration of them are herein omitted.

The preferred closures or other means having filtering area are preferably permanent fixtures 'used in a production line, and are in preferred practice removedafter each use. However, these may be of other structure, for example, metal or cloth filters of such character that they need not be removed. Whenretained, they may be a permanent part of the final structure, covered or 'not. Hence, the'removal of such closures is not considered an essential part of the process. But in certain cases it may be included as an essential part of certain aspects or variations of the invention. l y

The present invention maybe used forfibers, 'fiakes and particles of other forms. Examples of fibers are hair, wood fiber, vegetable fiber, kapok, mineral wool, glass wool, asbestos, straw, grasses and many others. Examples of other materials are flaked paper, exfoliated vermiculite, inica, ground cork and like materials. Fibers are preferred, because they mat and felt and produce stable forms in more complex variations of the invention where fixtures may be used and removed. The following illustrations are, therefore, given with respect to wood fiber, such as that according to my said copending application Serial No. 336,495, filed May 22, 1940, now Patent No. 2,325,055, issued July 7, 1943, which was developed primarily for use in the present invention.

The invention involves the building up of a consolidated gas-filtering body of particlesiof insulating material introduced as suspended matter in a stream of gas, into a confined space to be insulated; 'and'itinvolves'the provision in the confining walls of said space of filtering area to retain the particles and exhaust the gas. The location of inlet area, the number ofinlet areas,

tat-sate and the" location;. size; and number' of filtering areas "are not critical I with respect to: any given space. 'Ihisis because the" stream of" gas is-introduced at avelocity to impel the particles-"with turhulenceintdthe" space 'and to-all parts-"ofthe space; The greater the shortest i distance from inlet area to filtering-area; the thickeris the body of insulating material through which gas must pass" to exhausti Therefore; for practical convenience, ,it is desirab'leto have filteringarea close-to; or-even adjacent toinlet' area; Experi'-.

ence has shown that" because of the" turbulence; the particlesmay-' deposit in regions someoi which are adj acent' t'o filtering area; and others of 'which are remote from' both" inlet'area and filtering area.- Theresulting deposit grows towardthe'inlet area; andto orthrough the inlet area: In such case; the-filtering area close tooladiecent inlet areafacilitates the deposition of tha last-depositedmaterial; The conditions establish acomplexity" of air-' currents which change as theremaining spaceto* be filled changes: Gyclcnic currentshave been observed which tend to: throw carried particles centrifugallyout-of the -local 'a-irstream'and-depositthem brcentrifugal forceand in the manner described. Also directdeposition by filtration has been observedasoneof the-resulting actions-to deposit theintroduced particles.

In Fig; 1* there is illustrated a refrigerator cabinet anda food compartment therefor lifted out of said cabinet. The cabinet comprises a box=like steel form' Ill havingaback HgShOWIl in-liorizontal position but normally being verticalttwo refrigerator sides" 12; refrigerator top I3, cabinet bottom- I4 and" asupporting housing 'I he' food 'compartment is generally designated 2:0 It: abaclcpanel 21; sides 122 top 23, bottom 24; an opening-25 in the back panelifor use in connection witharefrigerating unit to. be insertediintheioodficompartment: The food'compartmenttisof a si-ze to' fittwithin the flange I551 The lip l5 receives screwstby on the-cabinet which breaker strip materialis secured. to. it,

and to the walls of the food compartment, at

the ten thereof; to: close agap between them. This provides space all around the food: compartment' to receiveinsulation, which space also has-aboxelikeform;

According to thepresent invention, the food compartmentiis not within the cabinet when. the insulation-is placed; Rather, there is provided as. fixture which is: a substantial: dummy for the? food compartm'ent.withzrespectto. the faces cnthefood compartment which are to contact the 'insulation; Preferably; the likeness is exact, but if 'it deviates, it: is preferred that-the'dummy provide; thicker space than. is. provided by the f and: compartment, whereby. the: food i compartment can compress the deposited. insulation. However, the? dummymaso b'e larger in these respectsyin the caseswhere the deposited mass expands..- slightly= upon: removal of L the dummy. Suchaexpansion occurs with:deposited wood fiber, andfiifi ist greatestiif: removal of the .dummy occurseimmediately arten deposition. Ifiith -e :wood

. 6 fiber-is" allowed to stand in the compressed 'state of original depositicnithe" initial elasticity; to expand is tOalarge degreelost by rearrange ment of the fibers into a more thoroughly felted form.

In the present description it is considered that the dummy is the same size as the food compartment in the said respects, merelytdsimplify the structures tobeillustrated. i

Fig. 2 shows such a dummy fixture,,described in my earlier: parent application Serial; No. 294,212.. ,As therein described; it" was designed for use'in arefrigerator cabinet at either topor bottom of which therewas notspace-tobe insulated adjacent the food compartment. Hence, one illustrated" wall" ofitheifixture is shown-as imperforate. It has been. usedfin axreii'igerator where ,the insulation abovethe food. compartment is solid] b'oard,-asyofffiber or cork,,to. give support to heavy mechanism locatedj'abovejitiin the cabinet body. However, such a fixture-islalso useful where there is space adjacent such imperforate fixture Wall to be insulated by the present invention. Theprocess is such that-thematerial WilLdepOsit behind all the:walls of therillustrated fixture, so longas there-isinlet-areaandfilterin area in the Walls confiningxthe whole space toib'ei insulated. V

In Fig. 2 there is represented a box-dike fixture 351 which in form isa substitute forthefood compartment 20' to define the same insulating spaces inside the cabinet. H], betweenthewalls of the fixtureandthewallsof the cabinet 'l hewalls ofthe fixture are designated: end .31, end 32,;bottom 33, and-sides,;3li and 35., The-pan'e1S -33-, 3 l; and 35- have two inlet v areas. respectively 36. -and 31, 38 and 39, and Ml an'd 4|. Theend paneLBZ hasone i inlet. opening, 42; A; complex: unitary, pipe fixture is. shown in perspective in-Fig. 2,- Which is illustrated. asiremoved from the box.- fixture 30, of which; it isractually a part built into it; The pipe fixturehasagmain feedtline 43, for examplaof 4-inch diametersheet metal pipe, with 3-inch diameter,take-offstdesignated by: numerals already assignemto the feed openings. Either end or both-endsqofi'the 'main feed line -43 may be used to admit air carryinginsulating material. One: end. 44-i$$hQWR ascIosed;

Each panel has a ,closed or.- imperforateperipheral area forming a frame andithe:framewpening may be screened, except where; there is afeed opening or inletiareal Imdetail thepanels; alliexcept panel 3|, have. screen areas; of; wire c1oth45. In the actual-construction; the ends of th feedpipes are secured -to-thescreens, for

attachment to a fiber-air supply; .andzforremoval.

from the integralfelted jacketformed about it in the cabinet.

When the fixture is withdrawn, the peripheral:

space is filled with a box-like unitary. mater body which is self-supporting: with the fixture withdrawn. With simple precautions the' food compartment is" then inserted and secured: in final position.

The following illustrates means. for blowingparticles to the fixture; Consider. the apparatus of Fig.3, having a fan-type blower 45; It-has a conduit 46 for entry of air; into whichhberis six inches diameter and connected 430- a space to-be filled. The fands-operated at 3 R. P. M. by a 15 H. 2. motor of 1800 R. P. M. Running idle, (connected and operated but no fiber fed), the measured pressures are as follows:

The blowing system was used to fill a space A full, then again to /z full, then to full, and then to 100% full, with measurements of the system (idle) at each stage. The measured values are combined in Table II with values taken from Table I and are in the same units as those in Table I.

.Table II Measured in pipe 47 Empty 34 full 34 full full Full It is noted that under conditions where the exit is wholly or to a degree blocked, as when the space is full, there is a back pressure encountered at the inlet to the centrifugal fan.

The back-pressure is an important feature of the use of super-atmospheric pressure feed, with apparatus permitting back pressure. Consider in Fig. 3, that the fan may run while the feed line 41 is open. A momentum is established into pipe 41. As this is blocked off, the moving stream is retarded, at first in part, and fiber gradually fills up the inlet conduits. A window (later described) indicates this and the process may be stopped. If not stopped, the back pressure at the inlet blows fiber back in pipe 46. Thus; fiber fed into the inlet will also be blown out the inlet. The appearance of back-feed or back-pressure is an indication of the final status of being filled.

Many factors influence the result, and practically it is necessary to arrive at standard conditions for the particular equipment used, and the job at hand. For example, it has been found to .be a general rule that the faster the fiber is fed, the less the density of the mat obtained. However, this rule is limited to a very short period of time. In one tested instance the feeding time for the space was varied from fractions of a. minute to several minutes. The curve of density has been plotted vertically against feeding time plotted horizontally. The curve rises rapidly, and at about 25 seconds it begins to flatten out. In about 60 seconds it has reached a maximum density. Such curves were obtained with different fan speeds, and it was found that high speeds (greater kinetic energy to fiber) at the same feeding time gave higher density mats. By constructing such curves from experimental procedure, the conditions for most efficient operation and for uniform operation may be easily determined.

Fig. 4 represents a second and a preferred form of fixture in which both inlet area and filtering area are more limited, and imperforate area is more extensive. Simplicity of fixture structure is evident, and filtering area is arranged with respect to the more limited inlet area, to secure good formation and stability of the deposit, when of wood fibers, against collapsing on removal of the fixture. r V

Fixture of Fig. 4 has 5 panels, including bottom 50, and two short sides 5| and 52 and two

long sides

53 and 54. The inlet area 55 is in the central part of bottom 50, and is connected to fiberair conduit 56. At the corners of the bottom are small triangular filtering areas 51 of screen wire. Each of the fixture side walls has like triangular filtering areas 58 of screen Wire adjacent the areas 51. At the top of the side walls of the fixture are disposed near each corner narrow horizontally elongated screen areas 59. On the

longer side walls

53 and 54, there are in the vicinity of the center, two narrow vertically elongated filtering areas 60 and 6|, spaced apart. The function of these is to vary the fiber formation from that which would result from omission of the areas 60 and 6!, whereby a reinforcing formation occurs. This is described in the copending application of Pauley, Serial No. 439,678, filed April 20, 1942, wherein the same fixture is illustrated and specifically claimed. A window 560, is shown in the conduit 56 to indicate over-filling by the appearance of packed fiber at the window. 7

Fig. 5 illustrates the nature of the fiber deposit formed in the cabinet Ill, using the fixture of Fig. 4. The areas formed adjacent filtering area are shown by stippling, except the areas formed adjacent screens 60 and 61. The latter areas in the mat are designated 6| and 62. Screen areas 69 and BI tend, as do other screen areas, to cause the deposit to grow away from them, and they also cause an accumulation of fines to act as reinforcement. The lines of growth give a grain to the deposit and by mixing the grain by coaction of the horizontal and vertical areas illustrated, the vertical walls of large area in the final deposit are stronger and do not collapse.

Fig. 6 is a fragmentary section on line 6--6 of Figs. 4 and 5, showing the wall IU of the cabinet, screen 65 of the fixture, imperforate side wall 54 of the fixture, and fiber 62 heterogeneously arranged and more compact adjacent screen area 60, and a grain extending away therefrom, the drawing being indicative rather than exact.

Filtering area is' not essentially limited to a removable fixture, in practicing the invention, andmay be located anywhere in the total area confining the space. Thus, in Fig. 1, a hole 28 in wall l4 for connections to the refrigerating unit may be temporarily covered by screen 29.

, A possible modification of the process is to use the fixture Fig. 4 with the inlet area thereof blocked off or removed, and replaced by inlet area on the cabinet. Where there is anopening H5 in the cabinet, which in Fig. l is shown as closed by the platform I! beneath it, there may be an inlet opening provided in the platform. The opening l6 may be placed over this inlet area in the platform. The results will be the same, since it is immaterial in which direction the air stream moves as it enters the back panel space between the back wallsof the cabinet and the fixture.

The. invention is not limited to refrigerators and has numerous applications wherein dummy fixtures may be employed. Figs. 6 and 7 illustrate but one of these different. fields. In Fig. 7 the box 10 illustrates the casing of a carboy in inverted position, with the bottom removed, on which bottom a, flask or bottle normally rests. There is shown in the box, a unitary fixture H which is I substantially a dummyfor the. major ternal fl'ange l fitting the casing :and located at the level for the bottom of Itheibottle, At the region where thefiangejolns theqbody, there are plurality of wire screens 16 forming filtering area. At the center is aeonduit 11 secured -by braces 18 to'the body '12. The -conduit -branches intortwo parts -1-9' and-8U whichtermihaLteatdnlet areas ill and 82m thevicinityor the shoulders 13.

ln use a stream ofair in which fiber orthe like is suspende'd is blown in-via-conduit IL-at -a high velocity creating a turbulence of air and particles in the confined space, and carrying particles to all portions of the space. Particles pack against the filters 16 and a deposit grows, filling all the space at least to the inlet areas 8| and B2, and even into the conduit if blowing is continued. The fiber or other body is designated 83.

Then the fixture H is withdrawn (see Fig. 8), exposing hole 85 in the casing (normal top), which hole is large enough to receive the mouth 86 of bottle 81, which is shown in position replacing the removed fixture H. Then means is inserted which spaces the bottle laterally from the casing sides and from the casing floor. Pref erably, this spacer as to the casing floor is insulating and cushioning, and a thick pad, or fiber board 88 is suitable. Blocks of wood, fiber board, or other material, 89, for lateral spacing, may be suitably secured in the casing, as by being mounted to the board 88. Then the floor 9!] of the casing is secured in position.

It is pointed out that, if the space occupied by the fiber board 88 were by some modification of the process blown to a density of the indicated mass 83, it would be subject to compression by the weight of the filled bottle in upright position. Dropping of the bottle from this cause would affect the packing 83 in the vicinity of the shoulders of the bottle.

Although I have shown all the inlet area located in the various fixtures illustrated, it is to be understood that this is only the preferred practice. Inlet area to the space may be one or more areas and be located anywhere in the walls, and the same is true of filtering area; but in order that the fixture may have a function for the process, either inlet area or filtering area isprovided in the fixture, preferably both, and pref erably all the inlet area and all the filtering area.

The use of a fan is preferred for the reason that it is a means of unfelting the fibers to substantially individual fibers. It is this form which gives the belt results. However, broadly, the fibers need not be completely unfelted, and may be in clusters or small aggregates. Use of other means, such as vacuum 0n the screen end, or feeding fiber directly into a current of air, is conducive to providing such loose aggregates, rather than individual particles of fiber. The important point is that these are not under mechanical pressure to felt them, and they tend to unfelt in process.

The terms screening means and filtering area" as used herein or in the claims refer to an area with any effective lattice or perforated member which acts as a screen to filter particles from the carryin gas, and it is to be distinguished from a member porous to air and from a crack or an elongated slot.

The location and size of filtering area relative to inlet area, and the velocity of the stream of gas, are all such that particles are introduced withiturbulence innlhportions ofithespace to be filledrand'pack therein.

Numerous modifications of lthe invention are eontemplateddn the app nded: claims.

I claim: n 1- Themethod which comprisesqinsertingan'einsulation-:fnrming materialtwhich are capablero'f paekin itoiform a {consolidated gas-filtering insulating body thereof and turbulently filling said space with said suspension, simultaneously separating said particles from said gas and venting the gas from said space at one or more predetermined locations in the defining walls of said space until said space is packed with particles in the form of said insulating body, and then withdrawing said fixture from said casing.

2. The method which comprises inserting a removable fixture into a casing through an opening therein and thereby defining a space by the exterior walls of said fixture and the interior walls of said casing, sealing said space against substantial leakage, introducing into said space at one or more predetermined locations a gaseous suspension of particles of thermal-insulation-forming material which are capable of packing to form a consolidated gas-filtering insulating body thereof and turbulently filling said space with said suspension, simultaneously separating said particles from said gas and venting gas from said space at one or more predetermined locations in the walls of said fixture until said space is packed with particles in the form of said insulating body, and then withdrawing said fixture from said casmg.

3. The method of insulating a refrigerator which comprises inserting a removable fixture having substantially the size and shape of the inner food compartment into the outer casing of a refrigerator through the door opening of said.

casing, sealing the intermural space defined by the inner walls of said outer casing and the walls of said fixture against substantial leakage, introducing into said space from one or more openings in the walls of said fixture a gaseous suspension of particles of thermal-insulating-forming material which are capable of packing to form a consolidated gas-filtering insulating body thereof and turbulently filling said space with said suspension, simultaneously separating said particles from said gas and venting gas from said space at one or more predetermined locations in the walls of said fixture until said space is packed with particles in the form of said insulating body, withdrawing the fixture from the outer casing, and mounting in the resulting cavity a food compartment to be insulated by said body.

4. A removable fixture to be confined within a casing for depositing particles of insulating material in said casing and against said fixture as an insulating body, said fixture comprising insulation-confining walls including one or more foraminous areas at predetermined locations acting as filtering means to hold said particles and vent gas, and having one or more openings at predetermined locations for discharging to the exterior of said fixture, and pneumatic conduit means terminating in said one or more dischar openings.

5. A removable fixture to be confined within a casing for depositing particles of insulating material in said casing and against said fixture as an insulating body, said fixture comprising insulation-confining walls including one or more foraminous areas'at predetermined locatiorisactin as filtering means to hold said particles and vent gas and having one or more openings at predetermined locations for discharging to the exterior of said fixture, there being at least one insulation-confining wall containing at least one foraminous area and at least one discharge opening, and pneumatic conduit means terminating in said one or more discharge openings.

CLARK C. HERITAGE.

REFERENCES CITED The following references are of record in the file of this patent: 1

UNITED STATES PATENTS Date Manning Aug. 18, 1936