US2076994A - Sound absorbing material - Google Patents
Sound absorbing material Download PDFInfo
- Publication number
- US2076994A US2076994A US751021A US75102134A US2076994A US 2076994 A US2076994 A US 2076994A US 751021 A US751021 A US 751021A US 75102134 A US75102134 A US 75102134A US 2076994 A US2076994 A US 2076994A
- Authority
- US
- United States
- Prior art keywords
- mold
- sound
- particles
- facing
- sound absorbing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000011358 absorbing material Substances 0.000 title description 6
- 239000000463 material Substances 0.000 description 47
- 239000002245 particle Substances 0.000 description 24
- 229910052500 inorganic mineral Inorganic materials 0.000 description 18
- 239000011707 mineral Substances 0.000 description 18
- 239000004568 cement Substances 0.000 description 10
- 239000000203 mixture Substances 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 238000000034 method Methods 0.000 description 7
- 229920001971 elastomer Polymers 0.000 description 6
- 239000004033 plastic Substances 0.000 description 5
- 230000001413 cellular effect Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000004576 sand Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 235000019738 Limestone Nutrition 0.000 description 2
- 239000011398 Portland cement Substances 0.000 description 2
- 208000027418 Wounds and injury Diseases 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 229910010293 ceramic material Inorganic materials 0.000 description 2
- 230000003749 cleanliness Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 208000014674 injury Diseases 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 239000006028 limestone Substances 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 235000013382 Morus laevigata Nutrition 0.000 description 1
- 244000278455 Morus laevigata Species 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000007767 bonding agent Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000006071 cream Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000013013 elastic material Substances 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 230000009970 fire resistant effect Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/62—Insulation or other protection; Elements or use of specified material therefor
- E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
- E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
- E04B1/84—Sound-absorbing elements
- E04B1/86—Sound-absorbing elements slab-shaped
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/62—Insulation or other protection; Elements or use of specified material therefor
- E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
- E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
- E04B1/84—Sound-absorbing elements
- E04B2001/8457—Solid slabs or blocks
- E04B2001/8476—Solid slabs or blocks with acoustical cavities, with or without acoustical filling
- E04B2001/848—Solid slabs or blocks with acoustical cavities, with or without acoustical filling the cavities opening onto the face of the element
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/62—Insulation or other protection; Elements or use of specified material therefor
- E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
- E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
- E04B1/84—Sound-absorbing elements
- E04B2001/8457—Solid slabs or blocks
- E04B2001/8476—Solid slabs or blocks with acoustical cavities, with or without acoustical filling
- E04B2001/848—Solid slabs or blocks with acoustical cavities, with or without acoustical filling the cavities opening onto the face of the element
- E04B2001/8485—Solid slabs or blocks with acoustical cavities, with or without acoustical filling the cavities opening onto the face of the element the opening being restricted, e.g. forming Helmoltz resonators
Definitions
- This invention relates to improvements in the construction and manufacture of sound absorbing wall-forming material of the cast or molded mineral types. Such materials are employed for 5 the control of acoustical conditions which are present in auditoriums, halls, rooms, theaters, subways or vehicular tunnels where the minimizing of sound and its general correction to establish improved or desirable sound effects constil0 tutes an important consideration.
- porous or cellular wall-forming materials which usually comprise preformed panels or blocks composed in certain instances of heattreated ceramic materials having rough uneven exposed surfaces with which the small internal voids or cells communicate, whereby to receive sound waves or disturbances which impinge thereon to4 absorb such sound and prevent its reflection as occurs with the use of wall-forming materials having smooth dense exterior surfaces.
- Such sound absorbing panels of a generally porous character have also been formed by suitably bonding small graded particles of a rocklike material in which a cementitious bond is used,A or by the employment of blast furnace slag crushed into particles of desired size and suitably united to produce wall-forming panels.
- minerals such as cyanite have been rendered cellular 'or porous through heat treatment in expanding temperatures, and the expanded particles united by a clay bonding agent.
- the hardened or molded product may without any difficulty at all be readily removed from the mold in a finished, perfected and desired state, this operation being such as to form the openings or perforations in the facing materials 45 in an entirely satisfactory manner and at the same time avoids injury to the mold upon the withdrawal of a formed block or panel.
- Fig. 1 is a plan view of a panel of sound absorbing material formed in accordance with the present invention
- Fig. 2 is a vertical sectional view taken through 55 10
- Fig. 7 is a. transverse sectional view taken therethrough on the line VII- VII of Fig. 6.
- the numeral I designates a block or panel of sound absorbing material formed to comprise a body 15 portion 2 and a facing layer 3, which may be applied to one or more surfaces of the body material.
- the body material- is of a generally porous character and may be produced in accordance with the disclosures contained in a prior appli- 20 cation, Serial No. 630,086 filed August 23, 1932 led by A. H. Sexton and F. R. Kanengeiser.
- One method of forming the body 2 may consist as set forth in the aforesaid prior application, in the employment of crushed substantially uniformly graded limestone particles which are first water soaked to substantially the limit of their water absorbing capabilities, and wherein dry cement alone is added to these particles, following .the removal of excess moisture, to provide a bonding medium whereby these particles of mineral matter may be united through molding in a o desired homogeneous manner, but at the same time producing voids or interstitial spaces 4 between the mineral particles which are known to ⁇ be effective in their ability to absorb and control sound.
- I employ a mold 5 of suitable shape and dimensions which includes a'bottom 6, upstanding vertical side walls 1 and an open top. 'I'he bottom of the mold is provided with a plurality of integral, relatively spaced upstanding projections or pins 8 which are of a length preferably exceeding the thickness of the facing layer 3 of the improved sound absorbing material.
- the entire mold in- 55 cluding the projections or pins 8 is formed from live rubber, possessing the ability to stretch or flex quite readily.
- the materials constituting the facing layer when in a substantially fluid state, possessing substantially the consistency of a thick cream are poured onto and over the bottom of the mold around the pins or projections 8, the depth of these forming materials being preferably less than that of the height of the projec- 05 tions 8 so that the upper ends of the latter will be visible after the facing layer has been poured.
- the materials comprising the facing layer may of course vary greatly, and I have used successfully in one form of my invention a cementitious mixture composed of approximately equal parts of a fine Ottawa sand and Portland cement, to which I add a sulcient amount of water so that the resulting mixture will possess free flowing and readily moldable properties.
- suit- 75 able mineral oxide coloring matter' may be added to this facing layerl to'prduce desired cl'o'rueffects, after the disclosures set forth in the prior application of A. H. Sexton, Serial No. 633,158 filed September 14, 1932.
- the body forming materials may then be added to the mold to approximately the height of the side walls 1.
- These body materials maycomprise a plastic mixture composed of crushed minerals of substantially uniformly graded particles of irregular shapes possessing the ability of absorbing water to an extent varying from 6% to 15% by weight thereof.
- This material ordinarily is composed of non-metallic minerals having sufficient hardness and permanency so that they will not disintegrate by elemental exposure and are carefully graded as to size within comparatively narrow limits.
- these mineral particles may be graded between screens composed of from 6 to 12 strands to the inch, or between screens of 10 to 20 mesh, or in certain instances 20 to 30 mesh, each grading to be handled separately.
- This plastic material is then placed in the mold 5 on top of the facing materials and molded sufilciently to cause the cement coatings, which surround each of the mineral particles, to coalesce or bond with similar coatings on adjacent aggregate particles.
- the resultant material after it has been allowed to dry and harden, comprises a porous product with a variety of interstices of different sizes communicating with one another and formed in said body between the individual cement coated particles. It is important that the material used as an aggregate should be the product of a crushing operation, so that there Will be formed irregularly shaped pieces and all approximately of the same size, whereby when this mass is cemented together, the interstitial pores or passages of varying area will be produced.
- My invention thus provides an acoustical material of high sound absorptive value and at the same time a material which is highly fire resistant.
- the facing material is integrally united with the body material so that there can be no separation therebetween.
- the removal of the molded product from the mold takes place easily and without the aid of machinery. This is due to the fact that the mold proper is flexible and, as stated, is formed from rubber. If there is any tendency on the part of the projections or pins 8 to adhere to the walls of the perforations 9 formed in the facing material, this tendency is immediately relieved by the stretching of the pins 'or projections, which results in decreasing their diameter so that they readily pass out of the perforations 9.
- the side walls 'l of the molds may be readily disengaged from the marginal edges of the mold block or panel I. Furthermore, there is little or no tendency of the material to cling l0 to the ⁇ rubber surfaces, and there takes place a sharp separation which leaves the mold in a cleanly condition, particularly at its corners, so that it is unnecessary to subject these molds, as is the case with metal molds, to thorough cleans- 15 ing before they can be re-used.
- the peg-like projections 8 are extended upwardly from the bottom of the mold a sufficient distance to penetrate into the 35 mass of the acoustical body material.
- the facing material it would seem, apparently increases the total sound absorbing capacity of the material rather than to decrease it. 'I'his undoubtedly is due to the fact that once the sound wave has 40 penetrated through the perforations 9 into the inter-communicating cells or pores of the body material, and the solid facing holds a greater percentage of the sound wave within the mass of the body material until it finally dies.
- an improved sound absorbing material is produced both from the standpoint of its capacity to absorb sound and in addition, the improvement in appearance and cleanliness afforded the product by the outer facing. 50 ,as stated, this racing may be made up in a variety of patterns or to produce dierent color eifects, which fact materially contributes to its usefulness as a wall material.
- the block or panel is indicated by the numera1 I0 and is 'formed by first producing a primary fluid-like mixture composed principally of sand, cement and water so that it may readily flow over the bottom of a pan-shaped mold, simi- 60 lar to that disclosed in Fig. 4 with the exception that the upstanding pegs or projections are omitted.
- This primary mixture is distributed over the bottom of the mold in the form of a relatively lshallow layer of approximately the same 6* depth or thickness as the facing layer 3 in the previously described form of block.
- a molded wall unit for acoustical regulation comprising a porous base formed from a plastic molded composition of small uniformly sized crushed mineral particles united by a cementiousbinder and having formed therein a multitude of interstitial passages or voids between the mineral particles, and a facing layer having a smooth exterior surface integrally bonded onits inner side with said base, said facing layer being composed of sand and cement and having molded therein a large number of relatively spaced transversely extending openings for the transmission of extraneous sound to the sound absorbing voids and interstices ofsaid base.
- a molded wall unit for acoustical regulation of fixed determinable dimensions comprising a base composed of uniformly sized mineral particles united by a cementitious' binder to form a homogeneous material having disposed therein a multitude of interstitial passages or voids betweensaid particles, and a facing layer integrally bonded on its inner side with said base, said facing layer being composed primarily of sand and cement and having molded therein a large number ofk relatively spaced transverselyfextending openings for the passage of sound energy through said facing layer.
- a building unit of predetermined dimensions comprising a base composed of crushed substantially uniformly graded limestone particles and a cementitious binder permanently joining said particles to produce a homogeneous composi-l tion having throughout its structure a multitude 4
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Electromagnetism (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Building Environments (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Description
il( l' I oooooooooowdoooo OOOOOUOOOOOOOUOOOOOO 0000 OOO 0000000000000 Lloloiooloo *\|ooo0000000oooooooo00| 000000000 0000000000 00000000000000000000 000000000 0000000000 00000000000000000000 000000000 00000.00000 lwwmhmv., 00000000000000000000 000000000 0000000000 wAw/a 00000000000000000000 000000000 0000000000 oooooooooooooooooooo 00000000000000000000 00000000000000000000 000000000 0000000000 00000000000000000000 0 000000000 0000000000 00000000000000000000 000000000 0000000000 00000000000000000000 000000000 0000000000 00000000000000000000 wwwwwwwwwowwwwwnovwmww 0 ooooooooooooooonvooo OOCOOOOOO 0000000000 j 00000000000000000000 000000000 0000000000 f 00000000000000000000 000000000 0000000000 y U 0..,0 J 00000000000000000000 ooooooooo 0000000000 0 (2 gdwda 00000000000000000000 000000000 0000000000 ,WQ as da! Ga@ 00000000000000000000 000000000 0000000000 7% un /J 00000000000000000000 000000000 0000000000 0 9 9v Jv 00000000000000000000 000000000 0000000000/ V9 vff /d/ja 00000000000000000000 000000000 00000000 P KA 6b 00000000000000000000 000000000 00000000?. K9/v9 5 j 00000000000000000000 000000000 0000000000 n, 9 yDJw/.D 00000000000000000000 000000000 0000000000 l @,f fO, 00000000000000000000 000000000 0000000000 v50 00000000000000000000 000000000 0000000000 JMrsQ /o .00000000000000000000 000000000 0000000000 uff? nvag f 00000000000000000000 \l\ 000000000 00000000.00 $18 JJ. .040! 00000000000000000000 7 000000000 0000000000 000Y dla i 00000000000000000000 ooooooooo 0000000000 @naald/4. 4,077 00000000000000000000 000000000 0000000000 $000.0@ 92 9.9 00000000000000000000 000000000 oooooooooo ufff p 99V 000000000 0000000000 krplull i* ooooooooomoooooooooo vmoovaadaym/df 000000000 0000000000 wvvwdr$00 U unido Ouai ,W Afd/o f Patented Apr. 13, 1937 UNITED STATES PATENT OFFICE 3 Claims.
This invention relates to improvements in the construction and manufacture of sound absorbing wall-forming material of the cast or molded mineral types. Such materials are employed for 5 the control of acoustical conditions which are present in auditoriums, halls, rooms, theaters, subways or vehicular tunnels where the minimizing of sound and its general correction to establish improved or desirable sound effects constil0 tutes an important consideration.
To secure these and other results, porous or cellular wall-forming materials have been developed which usually comprise preformed panels or blocks composed in certain instances of heattreated ceramic materials having rough uneven exposed surfaces with which the small internal voids or cells communicate, whereby to receive sound waves or disturbances which impinge thereon to4 absorb such sound and prevent its reflection as occurs with the use of wall-forming materials having smooth dense exterior surfaces. Such sound absorbing panels of a generally porous character have also been formed by suitably bonding small graded particles of a rocklike material in which a cementitious bond is used,A or by the employment of blast furnace slag crushed into particles of desired size and suitably united to produce wall-forming panels. Again, minerals such as cyanite have been rendered cellular 'or porous through heat treatment in expanding temperatures, and the expanded particles united by a clay bonding agent.
There are also other methods of forming these sound absorbing blocks or panels which produce products varying more or less in their relative ability to absorb or control sound but in general they may be all characterized by the rough, porous and uneven texture of their exposed surfaces. This physical condition makes it very difficult,
and usually impossible, to wash or clean the exposed surfaces of such materials when they are assembled in wall-forming order, and this constitutes a serious objection to their use in many cases where otherwise they would be entirely satisfactory and generally desirable.
It is, therefore, one of the outstanding objects of the present invention to provide an improved wall-forming block or panel composed of a body portion of the desired cellular or porous character formed in any of the well accepted methods of manufacturing such porous sounding material, as above described or otherwise, and wherein such body material is provided withan outer facing constituting a relative thin coating of a dense smooth surface material, but wherein is included,
during its process of manufacture, a multiplicity of small closely related openings or perforations which extend to the cells, voids or interstices of the body material, so that sound waves striking the exposed surface of the facing layer will pass 5 through these openings or perforations and are thereby absorbed or trapped in the small voids of the body forming material with practically the same efficiency as if the rough texture of the body material were directly exposed to sound contact. l0 However, due to the presence of the relatively smooth exposed surface of the facing layer, the washing or cleaning thereof may be accomplished with ease and facility so that the wall-forming material, constructed in accordance with the 15 present invention may be maintained in a desired state of cleanliness.
To obtain these results, very considerable difficulty was encountered in the molding of the plastic materials in their formative state. Generally, 20 such sound absorbing materials are rst formed to produce a plastic mass, which is poured into metallic molds in order to produce panels or blocks of desired configuration. It was found to be impossible, in order to produce the per- 25 forations in the facing material as above described, to provide the bottoms of such metallic molds with a plurality of upstanding pins or projections for the reason that the cementitious or ceramic materials would adhere upon setting with 30 such pins or projections with such tenacity as to preclude the removal of the hardened panels or blocks following setting or heat treatment without injury to either the block, panel or mold.
I have discovered, however, that through the employment of a mold formed from an elastic material, such as rubber, or wherein the pins or projections of the mold used in forming the facing openings are composed of such elastic ma- 40 terial, the hardened or molded product may without any difficulty at all be readily removed from the mold in a finished, perfected and desired state, this operation being such as to form the openings or perforations in the facing materials 45 in an entirely satisfactory manner and at the same time avoids injury to the mold upon the withdrawal of a formed block or panel.
For a further understanding of the invention, reference is to be had to the following descrip- 50 tion and the accompanying drawing, wherein:
Fig. 1 is a plan view of a panel of sound absorbing material formed in accordance with the present invention;
Fig. 2 is a vertical sectional view taken through 55 10 Fig. 7 is a. transverse sectional view taken therethrough on the line VII- VII of Fig. 6.
Referring more particularly to the drawing, the numeral I designates a block or panel of sound absorbing material formed to comprise a body 15 portion 2 and a facing layer 3, which may be applied to one or more surfaces of the body material. The body material-is of a generally porous character and may be produced in accordance with the disclosures contained in a prior appli- 20 cation, Serial No. 630,086 filed August 23, 1932 led by A. H. Sexton and F. R. Kanengeiser. However, I do not limit myself to any particular method of forming or producing the body material, since it is within the scope of the invention to utilize any of the above described methods for producing a porous or cellular body through the employment of minerals which may be reduced to a moldable state and subsequently set or hardened by curing or heat treatment.
so One method of forming the body 2 may consist as set forth in the aforesaid prior application, in the employment of crushed substantially uniformly graded limestone particles which are first water soaked to substantially the limit of their water absorbing capabilities, and wherein dry cement alone is added to these particles, following .the removal of excess moisture, to provide a bonding medium whereby these particles of mineral matter may be united through molding in a o desired homogeneous manner, but at the same time producing voids or interstitial spaces 4 between the mineral particles which are known to `be effective in their ability to absorb and control sound.
In producing my improved product, I employ a mold 5 of suitable shape and dimensions which includes a'bottom 6, upstanding vertical side walls 1 and an open top. 'I'he bottom of the mold is provided with a plurality of integral, relatively spaced upstanding projections or pins 8 which are of a length preferably exceeding the thickness of the facing layer 3 of the improved sound absorbing material. Preferably, the entire mold in- 55 cluding the projections or pins 8 is formed from live rubber, possessing the ability to stretch or flex quite readily.
In the use of the mold, the materials constituting the facing layer when in a substantially fluid state, possessing substantially the consistency of a thick cream, are poured onto and over the bottom of the mold around the pins or projections 8, the depth of these forming materials being preferably less than that of the height of the projec- 05 tions 8 so that the upper ends of the latter will be visible after the facing layer has been poured. The materials comprising the facing layer may of course vary greatly, and I have used successfully in one form of my invention a cementitious mixture composed of approximately equal parts of a fine Ottawa sand and Portland cement, to which I add a sulcient amount of water so that the resulting mixture will possess free flowing and readily moldable properties. If desired, suit- 75 able mineral oxide coloring matter'may be added to this facing layerl to'prduce desired cl'o'rueffects, after the disclosures set forth in the prior application of A. H. Sexton, Serial No. 633,158 filed September 14, 1932.
Following the placing of this mixture of facing materials in the mold 5, the body forming materials may then be added to the mold to approximately the height of the side walls 1. These body materials maycomprise a plastic mixture composed of crushed minerals of substantially uniformly graded particles of irregular shapes possessing the ability of absorbing water to an extent varying from 6% to 15% by weight thereof. This material ordinarily is composed of non-metallic minerals having sufficient hardness and permanency so that they will not disintegrate by elemental exposure and are carefully graded as to size within comparatively narrow limits. Thus in one form of my invention, these mineral particles may be graded between screens composed of from 6 to 12 strands to the inch, or between screens of 10 to 20 mesh, or in certain instances 20 to 30 mesh, each grading to be handled separately.
Following the grading of these relatively small, uniformly sized and crushed or shattered mineral particles, the latter are then wetted by immersion or sprinkling until they have been saturated with water. Excess water may then be drained off after the mineral particles have absorbed substantially 6% to 15% by weight of water. Dry cement, preferably Portland cement, is then added to the water-containing mineral particles and the material agitated to obtain a thorough mixing of the cement with the wetted mineral particles. After this thorough mixing, which may be done in any character of apparatus, the mixture is placed on a screen having a mesh size less than that of the particles of the aggregates. All excess material, such as unwetted dry cement, is screened out of the mass, whereby to leave only such cement adhering to the surfaces of the mineral particles which has been wetted by the moisture present therein.
This plastic material is then placed in the mold 5 on top of the facing materials and molded sufilciently to cause the cement coatings, which surround each of the mineral particles, to coalesce or bond with similar coatings on adjacent aggregate particles. The resultant material, after it has been allowed to dry and harden, comprises a porous product with a variety of interstices of different sizes communicating with one another and formed in said body between the individual cement coated particles. It is important that the material used as an aggregate should be the product of a crushing operation, so that there Will be formed irregularly shaped pieces and all approximately of the same size, whereby when this mass is cemented together, the interstitial pores or passages of varying area will be produced. My invention thus provides an acoustical material of high sound absorptive value and at the same time a material which is highly fire resistant. When the molded product is removed from the mold, following the usual curing period, the facing material is integrally united with the body material so that there can be no separation therebetween. The removal of the molded product from the mold takes place easily and without the aid of machinery. This is due to the fact that the mold proper is flexible and, as stated, is formed from rubber. If there is any tendency on the part of the projections or pins 8 to adhere to the walls of the perforations 9 formed in the facing material, this tendency is immediately relieved by the stretching of the pins 'or projections, which results in decreasing their diameter so that they readily pass out of the perforations 9. Similarly, the side walls 'l of the molds may be readily disengaged from the marginal edges of the mold block or panel I. Furthermore, there is little or no tendency of the material to cling l0 to the `rubber surfaces, and there takes place a sharp separation which leaves the mold in a cleanly condition, particularly at its corners, so that it is unnecessary to subject these molds, as is the case with metal molds, to thorough cleans- 15 ing before they can be re-used.
There are numerous other advantages attending the use of the rubber mold, tray or palette in the manufacture of moldable products of the character set forth. By the use of rubber,'I can 20 obtain very intricate surface designs, also duplicate all sorts of fabric designs, wood grain or other patterns of a like nature. The use of rubber in the mold formation also permits of convenience in the casting of these intricate designsand the 25 stripping of the molded article from the mold.
Furthermore, it allows one to cast models in relief where under-cutting is necessary and gives a high degree of density and surface ilnish. These advantages are true whether the material 0 is employed for uses other than as an acoustical wall material.
It will be noted that the peg-like projections 8 are extended upwardly from the bottom of the mold a sufficient distance to penetrate into the 35 mass of the acoustical body material. The facing material, it would seem, apparently increases the total sound absorbing capacity of the material rather than to decrease it. 'I'his undoubtedly is due to the fact that once the sound wave has 40 penetrated through the perforations 9 into the inter-communicating cells or pores of the body material, and the solid facing holds a greater percentage of the sound wave within the mass of the body material until it finally dies. By this 45.method and construction, an improved sound absorbing material is produced both from the standpoint of its capacity to absorb sound and in addition, the improvement in appearance and cleanliness afforded the product by the outer facing. 50 ,as stated, this racing may be made up in a variety of patterns or to produce dierent color eifects, which fact materially contributes to its usefulness as a wall material.
In the form of our invention disclosed in Figs. 55 6 and "I, the block or panel is indicated by the numera1 I0 and is 'formed by first producing a primary fluid-like mixture composed principally of sand, cement and water so that it may readily flow over the bottom of a pan-shaped mold, simi- 60 lar to that disclosed in Fig. 4 with the exception that the upstanding pegs or projections are omitted. This primary mixture is distributed over the bottom of the mold in the form of a relatively lshallow layer of approximately the same 6* depth or thickness as the facing layer 3 in the previously described form of block. We then substantially fill the balance of the mold with the porous body mixture which corresponds to that employed in the making of the body 2 with the exception that it is in a somewhat drier state so that this body material which is indicated by the numeral II, while the primary or facing layer is indicated by the numeral I2, will absorb moisture from the facing layer at such a rate as to produce a multiplicity of relatively small irregular openings or passages in the primary layer, which extend completely through the latter in order to establish sound communication between the exterior of the block and the internal voids of the body layer. 'Ihis form of block or panel, like the panel I, also presents a smooth finished exterior surface which may be readily cleansed by being washed or otherwise renovated. So far as we are aware, a sound absorbing materialhaving this property of being readily lcleansed or renovated is generically new and the claims herein- Iafter made are therefore to be construed ac-l cordingly.
What is claimed is:
1. A molded wall unit for acoustical regulation comprising a porous base formed from a plastic molded composition of small uniformly sized crushed mineral particles united by a cementiousbinder and having formed therein a multitude of interstitial passages or voids between the mineral particles, and a facing layer having a smooth exterior surface integrally bonded onits inner side with said base, said facing layer being composed of sand and cement and having molded therein a large number of relatively spaced transversely extending openings for the transmission of extraneous sound to the sound absorbing voids and interstices ofsaid base.
2. A molded wall unit for acoustical regulation of fixed determinable dimensions, comprising a base composed of uniformly sized mineral particles united by a cementitious' binder to form a homogeneous material having disposed therein a multitude of interstitial passages or voids betweensaid particles, and a facing layer integrally bonded on its inner side with said base, said facing layer being composed primarily of sand and cement and having molded therein a large number ofk relatively spaced transverselyfextending openings for the passage of sound energy through said facing layer.
3. A building unit of predetermined dimensions comprising a base composed of crushed substantially uniformly graded limestone particles and a cementitious binder permanently joining said particles to produce a homogeneous composi-l tion having throughout its structure a multitude 4
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US751021A US2076994A (en) | 1934-11-01 | 1934-11-01 | Sound absorbing material |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US751021A US2076994A (en) | 1934-11-01 | 1934-11-01 | Sound absorbing material |
Publications (1)
Publication Number | Publication Date |
---|---|
US2076994A true US2076994A (en) | 1937-04-13 |
Family
ID=25020138
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US751021A Expired - Lifetime US2076994A (en) | 1934-11-01 | 1934-11-01 | Sound absorbing material |
Country Status (1)
Country | Link |
---|---|
US (1) | US2076994A (en) |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3007539A (en) * | 1957-10-04 | 1961-11-07 | Reeves Bros Inc | Sound shield |
US3132714A (en) * | 1962-01-02 | 1964-05-12 | Aerojet General Co | Acoustic panel |
US20050211500A1 (en) * | 2004-03-26 | 2005-09-29 | Wendt Alan C | Fibrous faced ceiling panel |
US20070209867A1 (en) * | 2006-03-08 | 2007-09-13 | Jin Suk Kim | Soundproof panel for impact sound insulation |
USD848035S1 (en) * | 2015-07-03 | 2019-05-07 | Arktura Llc | Architectural fixture |
USD849275S1 (en) * | 2015-07-03 | 2019-05-21 | Arktura Llc | Architectural fixture |
USD849969S1 (en) * | 2015-07-03 | 2019-05-28 | Arktura Llc | Architectural fixture |
USD859696S1 (en) * | 2015-07-03 | 2019-09-10 | Arktura Llc | Architectural fixture |
USD965183S1 (en) * | 2020-03-03 | 2022-09-27 | Mitsubishi Chemical Corporation | Vibration control and noise insulation material |
USD976448S1 (en) * | 2020-03-03 | 2023-01-24 | Mitsubishi Chemical Corporation | Vibration control and noise insulation material |
-
1934
- 1934-11-01 US US751021A patent/US2076994A/en not_active Expired - Lifetime
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3007539A (en) * | 1957-10-04 | 1961-11-07 | Reeves Bros Inc | Sound shield |
US3132714A (en) * | 1962-01-02 | 1964-05-12 | Aerojet General Co | Acoustic panel |
US20050211500A1 (en) * | 2004-03-26 | 2005-09-29 | Wendt Alan C | Fibrous faced ceiling panel |
US20070209867A1 (en) * | 2006-03-08 | 2007-09-13 | Jin Suk Kim | Soundproof panel for impact sound insulation |
USD848035S1 (en) * | 2015-07-03 | 2019-05-07 | Arktura Llc | Architectural fixture |
USD849275S1 (en) * | 2015-07-03 | 2019-05-21 | Arktura Llc | Architectural fixture |
USD849969S1 (en) * | 2015-07-03 | 2019-05-28 | Arktura Llc | Architectural fixture |
USD859696S1 (en) * | 2015-07-03 | 2019-09-10 | Arktura Llc | Architectural fixture |
USD965183S1 (en) * | 2020-03-03 | 2022-09-27 | Mitsubishi Chemical Corporation | Vibration control and noise insulation material |
USD976448S1 (en) * | 2020-03-03 | 2023-01-24 | Mitsubishi Chemical Corporation | Vibration control and noise insulation material |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2045099A (en) | Cellular material and method of making same | |
US2018192A (en) | Method of producing cementitious tile | |
US1560450A (en) | Artificial stone and process of making | |
US1769519A (en) | Acoustical material and method of manufacturing same | |
US3077413A (en) | Ceramic fiber products and method and apparatus for manufacture thereof | |
US2076994A (en) | Sound absorbing material | |
US3247294A (en) | Concrete products and methods for making same | |
US2668123A (en) | Method of producing acoustical tile | |
US2172466A (en) | Mold | |
US2008718A (en) | Structural material and method of making the same | |
US1862688A (en) | Process for making a fibrous building material | |
US2021359A (en) | Preformed sound-absorbing unit and method of making the same | |
US3595947A (en) | Method of manufacturing structural elements | |
US2017587A (en) | Masonry faced wall board and process of producing the same | |
US2332703A (en) | Cement-fiber board | |
US2124086A (en) | Sound absorbing construction | |
US1344324A (en) | Light-weight artificial cement stone for building purposes | |
US1869367A (en) | Sound absorbing material and method of making the same | |
DE1508945B1 (en) | Method and device for the production of molded elements for lining block heads | |
US1952766A (en) | Sound absorbing material and method of making the same | |
US2006425A (en) | Process for the production of cementitious masses | |
US1578091A (en) | Process of manufacturing building blocks | |
US1358830A (en) | Sound-absorbing and heat-insulating material, and process for making the same | |
US1960440A (en) | Wall covering and process of making same | |
US1910844A (en) | Acoustical material |