CA2029072A1 - Texturing of acoustical mineral fiberboard with wheel blast machine - Google Patents
Texturing of acoustical mineral fiberboard with wheel blast machineInfo
- Publication number
- CA2029072A1 CA2029072A1 CA 2029072 CA2029072A CA2029072A1 CA 2029072 A1 CA2029072 A1 CA 2029072A1 CA 2029072 CA2029072 CA 2029072 CA 2029072 A CA2029072 A CA 2029072A CA 2029072 A1 CA2029072 A1 CA 2029072A1
- Authority
- CA
- Canada
- Prior art keywords
- fiberboard
- particulate material
- housing
- spent
- roof
- 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.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C3/00—Abrasive blasting machines or devices; Plants
- B24C3/08—Abrasive blasting machines or devices; Plants essentially adapted for abrasive blasting of travelling stock or travelling workpieces
- B24C3/10—Abrasive blasting machines or devices; Plants essentially adapted for abrasive blasting of travelling stock or travelling workpieces for treating external surfaces
- B24C3/14—Apparatus using impellers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
- B24C1/06—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for producing matt surfaces, e.g. on plastic materials, on glass
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B11/00—Apparatus or processes for treating or working the shaped or preshaped articles
- B28B11/08—Apparatus or processes for treating or working the shaped or preshaped articles for reshaping the surface, e.g. smoothing, roughening, corrugating, making screw-threads
- B28B11/0818—Apparatus or processes for treating or working the shaped or preshaped articles for reshaping the surface, e.g. smoothing, roughening, corrugating, making screw-threads for roughening, profiling, corrugating
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
- D21J1/00—Fibreboard
- D21J1/16—Special fibreboard
- D21J1/20—Insulating board
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Structural Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Dry Formation Of Fiberboard And The Like (AREA)
Abstract
TEXTURING OF ACOUSTICAL MINERAL FIBERBOARD
WITH WHEEL BLAST MACHINE
ABSTRACT
A method for texturing the surface of an acoustical fiberboard by utilizing a wheel blast machine. The fiberboard is conveyed through a housing wherein at least one first centrifugal blasting wheel throws abrasive particles at a portion of the fiberboard surface to abrade it. A blower provided in the housing removes spent abrasive particles thrown by the first wheel(s), and then at least one second centrifugal blasting wheel in the housing throws abrasive particles at the remaining untreated surface to complete the abrasion, whereby removal of the spent particles by the blower prevents masking of the surface and allows the formation of a pleasing and uniform pattern over the entire fiberboard surface.
WITH WHEEL BLAST MACHINE
ABSTRACT
A method for texturing the surface of an acoustical fiberboard by utilizing a wheel blast machine. The fiberboard is conveyed through a housing wherein at least one first centrifugal blasting wheel throws abrasive particles at a portion of the fiberboard surface to abrade it. A blower provided in the housing removes spent abrasive particles thrown by the first wheel(s), and then at least one second centrifugal blasting wheel in the housing throws abrasive particles at the remaining untreated surface to complete the abrasion, whereby removal of the spent particles by the blower prevents masking of the surface and allows the formation of a pleasing and uniform pattern over the entire fiberboard surface.
Description
~; 1 3 ~ 2 P ~TENT
;:1./03/83 :L
TE"TIJRING OF P,CGUSTI CAI. MINERAI. FIB RBOARD
WITH WHEEI. BLAST MAOEIINE
:BAC~GROU~ OF THE INVENTION
1. Field of the Invention This invention relates to a method and apparatus for producing an acoustical ~iberboard, and more particularly is directed to the s-~rface -texturing of a mineral ceiling panel with a wheel blast machine.
;:1./03/83 :L
TE"TIJRING OF P,CGUSTI CAI. MINERAI. FIB RBOARD
WITH WHEEI. BLAST MAOEIINE
:BAC~GROU~ OF THE INVENTION
1. Field of the Invention This invention relates to a method and apparatus for producing an acoustical ~iberboard, and more particularly is directed to the s-~rface -texturing of a mineral ceiling panel with a wheel blast machine.
2. Description of the Prior Art Shaped products made from fibers and a binder, which are typically acoustical :in nature, i.e., capable of attenuating sound, are well known in the art and are widely used today. Examples of such shaped products include ceiling panels and tiles, wall boards, screen dividers, construction panels, and the like. The conventional process for making these products involves use of a ~ourdrinier-type machine wherein an aqueous mixture comprisin~ the fiber and binder is cast on a forming screen, and subsequently consolidated and dewatered. Normally, the formed board is passed to an oven for final drying.
A wide variety of processes have been employed in the past to produce a textured surface on these ~iberboards, including cutting, routing, abrading, using adhesive inks or templates, etc. Frequently, i~ has been difficult to texture the boards without considerably weakening them or otherwise disadvantageousl~ affectin~ them. A particular problem has been to carry out the texturing in such a way that a pleasing and uniform pattern is created on the board while the overall board properties are preserved.
This problem is particularly exacerbatPd when the boards are extra wide and/or produced at high line speeds.
OBJECTS OF THE INVENTION
It is therefore an object oE the present invention to provide an improved method and appara-tus for decoratively ~ 130~ PAI'ENT
11/~3/8~ 2 2 lr3 ~ ~ ! I ;;1 -lexturing the surface of a fiberboacd, whereby a pleasing and uniform pattern is formed without substantially diminishing the board's physical properties.
It is a-nothex object of the present invention to provide a method of decorativ~ly texturing fiberboard, whereby a pleasing and uniform surface pattern is produced on extra wide boards being rapidly conveyed along a production line.
I-t is still another object of the present invention to provide a fine-textured fiberboard which is characterized by a combination of desirahle physical properties, including good strength and sound-absorption properties and a highly decorative and uniform surface pattern.
Other objec~s and advantages of the ~resent invention will become apparent to those skilled in the art when the instant disclosure is read in conjunction with the accom-panying drawings.
SUMMARY OF THE INVENTION
The present invention provides a me~hod for making an acoustic fiberboard, preferably a mineral ceiling panel, in which the surface of the board is textured by a wheel blast machine. The board product may be formed continuously by conventional wet prc>cesses wherein a water slurry of the board-forming ingredients is deposited upon a moving wire scr~en. The invention may also involve an operation s~hereby boards are formed in a cast process without water drainage from the product. After consolidation and drying, the board is abraded on either one of its two major surfaces.
The wheel blast machine comprises in sequence a first abxasive discharging means, a blower means and a second abrasive discharging means. As the dried board is conveyed through an abrading zone, abrasive particles are thrown by the first discharging means against the board to abrade its top surface. After thus impacting the surface of the board, spent abrasive particles collected on the board surface are blown therefrom by the blower means, 1332 .P~T~NT
A wide variety of processes have been employed in the past to produce a textured surface on these ~iberboards, including cutting, routing, abrading, using adhesive inks or templates, etc. Frequently, i~ has been difficult to texture the boards without considerably weakening them or otherwise disadvantageousl~ affectin~ them. A particular problem has been to carry out the texturing in such a way that a pleasing and uniform pattern is created on the board while the overall board properties are preserved.
This problem is particularly exacerbatPd when the boards are extra wide and/or produced at high line speeds.
OBJECTS OF THE INVENTION
It is therefore an object oE the present invention to provide an improved method and appara-tus for decoratively ~ 130~ PAI'ENT
11/~3/8~ 2 2 lr3 ~ ~ ! I ;;1 -lexturing the surface of a fiberboacd, whereby a pleasing and uniform pattern is formed without substantially diminishing the board's physical properties.
It is a-nothex object of the present invention to provide a method of decorativ~ly texturing fiberboard, whereby a pleasing and uniform surface pattern is produced on extra wide boards being rapidly conveyed along a production line.
I-t is still another object of the present invention to provide a fine-textured fiberboard which is characterized by a combination of desirahle physical properties, including good strength and sound-absorption properties and a highly decorative and uniform surface pattern.
Other objec~s and advantages of the ~resent invention will become apparent to those skilled in the art when the instant disclosure is read in conjunction with the accom-panying drawings.
SUMMARY OF THE INVENTION
The present invention provides a me~hod for making an acoustic fiberboard, preferably a mineral ceiling panel, in which the surface of the board is textured by a wheel blast machine. The board product may be formed continuously by conventional wet prc>cesses wherein a water slurry of the board-forming ingredients is deposited upon a moving wire scr~en. The invention may also involve an operation s~hereby boards are formed in a cast process without water drainage from the product. After consolidation and drying, the board is abraded on either one of its two major surfaces.
The wheel blast machine comprises in sequence a first abxasive discharging means, a blower means and a second abrasive discharging means. As the dried board is conveyed through an abrading zone, abrasive particles are thrown by the first discharging means against the board to abrade its top surface. After thus impacting the surface of the board, spent abrasive particles collected on the board surface are blown therefrom by the blower means, 1332 .P~T~NT
3/~9 ~, '`'~.,i2~ f3 thereby removing -these particl.es from the path of the next ~ollection of particles from -the second discharging means.
More partic-ularly, the present invention provides an apparatus for applying particulate material to the sl1rface of a fiberboard to be provided with a decorative pattern comprising:
(a) a closed housing having entry and exit slots for the fiberboard;
(b) means for conveying the fiberboard to be treated throug~ sai.d housing in a horizontal pos.ition;
(c) a first abrasive discharging means disposed within the housing above the surface of the fiberboard to be treated for applying particulate material to the surface thereofi ~ d) a blower means for removing spent particulate material collected on the surface of the fiberboard after discharge from the first. abrasive discharging means; and (e) a second abrasive discharging means disposed within the housing above the surface of the flberboard for further treatment of the surfac~ with particulate material.
The first and second abrasive dischar~ing means each advantageously comprise at least one centrifugal ~lasting wheel mounted in the roof of the housing to cause a portion of the fiberhoard surface to be uniformly impacted. The second discharging means is located downstream along the produc~ion line from the first such means in order to abrade the remaining fiberboard surface untreated by said first means. Air blown from a device such as an air knife removes spent particulate material left on the surface after its abrasion by the first discharging means. This removal allows the production of a highly decorative and uniform pattern on the surface of the fiberboard, DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the accompanying drawings in which:
E> 13 0 2 3~;9r:['ENT
L~JO~19 4 ?
FIC7. 1 is a diagrammatic, side elevational view o~ an a~paratus for carryillg out the method of the present in-~ention;
FIG. 2 is an enlarged cross-sectional view of the ~h~el blast machine shown in PIG. 1;
FIG. 3 is an enlarged top view of the wheel blast machine shown in FIG. 2, with certain parts being broken away for clarity; and FIG. 4 is an enlargcd perspective view of an air knife for rcmoving abrasive particles.
D:ETAILE.D DE~SCRI~TION OF T~IE INV~NTION
In carrying out the invention, a fiberboard sheet material, which may comprise inorganic and/or organic fibrous material and preferably consists of mineral fibers, a binder and the other board-forming ingredients, is produced in a conventional manner, such as on a wet board forming machine, e.g., a Fourdrinier or a cylinder machine. Referring now to FIG . 1, there is shown a machine chest 1 containing water to which the mineral fibers, such as conventionally felted mineral wool, are first added. Then the other ingredients, which advantageously consist o aqueous suspensions of perlite and optionally clay, oi starch, and of paper, are added to the machine chest. The machine chest agitator 2 is suitably operated to keep the slurry stirred up so that the ingredients are uniformly distributed throughout the slurry. The solids content of the slurry may be from about 2 to 8 we~ght r~ ~
In an advantageous embodiment of the invention, the fiberboard is produced from a slurry con~aining mineral fibers (e.g., mineral wool) which are nodulated during wet mixing of the slurry's ingredients~ To bring about substantial formation of nodulated wool upon mixing of the slurry, the consistency must be sufficiently high~ e.~.~
about 5 to 8, preferably 5.5 to 8, and more preferably 6 to 7.5 weight %. The formation of nodules of mineral fiber during mixing of the slurry may be brought about as desctibed in U. S. patent application Serial No. 210,446, 1302 ~;~$~,5~ 3 PAT~NT
11/03j39 5 f~ f~l f il ed June 23, 1988, the disclosure of which application is hereby lncorporated by rcference. The rate and duration of a~itation for forming an appropriate content of nodulated wool in the slurry can be readily determined through routine experimentation. Generally, the slurry is mixed for about 10 to 60 minutes by means of a rotary ayita-tor (impeller) revolving at a rate oE about 100 to 150 reYolutions per minute. Alternatively, the mineral wool may be introduced to the slurry in the form of pellets of previously nodulated mineral wool.
A~ter the slurry is agitated sufficiently to uniformly distribute the solids and, when appropriate, to nodulate the wool, the slurried composition is transferred by pump 3 through pipe 4 to head box 5. The slurry is subsequently deposited on Fourdrinier wire 7 through orifice 6 of head box 5. The first section 8 of the Fourdrinier wire permits free drainage of water from the material and urther draina~e is promoted by suction boxes 9 in section 10. As the slurry is brought in contact with the Fourdrinier machine and water of the slurry drains therefrom, a wet felted mat o~ the mineral fiber composition forms on the machine. The wet laid mat is dewatered by the Fourdrinier machine ~o a solids content ~f about 20 to 40 weight percent~
The partially dried material is then prepressed to a thickness of about 0.4 to 0.8 inch by a plurality of press rolls 11. It will be appreciated that a single set of press rolls could be employed i~ desired. After being pressed, the sheet product will generally have from about 60 to about 75% water. A coating may be applied to the pressed mat by means of feed-pipe 13 and coater 14.
After passing through press rolls 11, the wet mat is transferred into dryer 12. At the ou-tlet of the dryer, there is ob-~ained a board 15 having a moisture content of about 1.0%. The board is cut into smaller panels by saw arrangement 16. Dried boards having widths of 24 in. or more, e.g., 24 to 52 in.~ can be formed for texturing by the wheel blast machine o~ the invention. The dried 1302 r~TENT
11/03/89 6 ~ s~
product can he subjected to any suitable conventional finishing apparatus, depending on the applications for which it is in~ended. Such apparatuses may include applicators for applying coatings to protect and/or decorate the product surface, such as bevel coaters, finish spray coaters, printers, multi-color decorative coaLers, and the like, and further dr-,7ing equipment.
A fine-textured appearance is created on one of the two major surfaces of ~he dried board by the wheel blaster 17 of -the inven-tion. The board may be advantageously turned over by an inverter 18 to present the smooth scre~n side for surface treatment. The board is continuously passed by suitable conveyor means (e.g., conveyor rollers 19) through the wheel blast machine located on the production line. The housing 2~ of the machine has inlet and outlet openings 25 and 26 for the board. The process can be run at a line speed ol up to 200 lineal ~eet per minute. However, for optimum pattern uniformity, the line speed through the wheel blast machine generally should be about 150-180 lfpm. It is, of course, understood that the speed of the line can be readily adjusted so that the entire board surface will be uniformly subjected to the action of the abrasive spray from the wheel blaster. Even at quite high line speeds, the present invention makes it possible to produce pleasing and uniform patterns on boards which are much wider than conventionally textured boards. Whereas a typical width of a conventionally tex~ured board is about 2 ft., boards having widths up to 52 in. or more can be readily textured in accordance with the prPsent invention.
Referring now to FIGS. 2 and 3, it will be seen that conveyor rollers 19 carry fibrous board 15 khrough the housing 20 of the wheel blast machine to abrade and thereby decoratively texture the board surface with abrasive material 21 propelled by first abrasive discharging means 22. The first abrasive discharging means advantageously comprises one or more roof mounted centrifugal blasting wheels 22 located wlthin the blasting 1302 n PATENT
1~/0~/~9 7 ~d ~ 7,:~ ~J' ~ I 'd 1~
chamber directly above the conveyor means Eor dlrecting the abrasive material downwardly upon the board as it passes -through the chamber. When more than one blasting wheel is employed, such as the two shown in FIGS. 2 and 3, the wheels 22a, 22l~ preferably are staggered in a longi-tudinally spaced apart relation and in a laterally spaced apart relation to cause the top surface of the board to be uniformly impacted by the abrasive particles centrifugally thrown by the wheels, preferably at an acute angle with respect to said board surface. The desired effect of the spacing is that abrasive thrown by the first wheel onto the board will ricochet without passing through the path of abrasive particles thrown by the next wheel thereby to minimize interferences with the particles thrown at the surfaces of the boards and also to avoid undesirable cushioning effects. Wheels 22a, 22b are advantageously located so as to abrade the outer edges of the board.
The machine includes a second abrasive discharging means located within the blasting chamber downstream from the first such means. The second abrasive discharging means advantageously comprises one or more roof mounted centrifugal wheels 23 ~two shown in FIGS. ~ and 3) similarly spaced for uniform treatment and texturing of the board surface. Wheels 23a, 23b are suitably mounted to ~reat the interior portion of the board. The ~hrowing wheels may be of conventi~nal type described in the art, and can be obtained from ~7heelabrator-Frye, Inc.
The surface-treating material 21 may be ~ny abrasive capable of texturing the surface of the board. Both "heavy" abrasives (e.g., metal grit or shot) and "light"
abrasives, which are of softer materials than the former type, may be used. "Light" abrasives include such items as glass shot, plastics, walnut shells, pecan shells, corn husks, peach pits, etc. Typically, the surface abrasion removes about 0.01-0.04, preferably .025 - .035, inch of the board surface in producing the desired look.
~epending on factors such as the type of abrasive and 11~03/89 8 ~ ?~ T~
board being treated as well as the spatial relationshlp o-E
th~ wheels and board, the wheels can be operated at various speeds, such as from about 1800 to 3600 rpm.
~ bLasive granules thrown by the first discharg:ing means against the upper surface o-f board 15 rebound therefrom and collect lnside cabinet 20 and disadvantage-ously on the board surface. If this spent blast medium is not removed from the surface of the board prlor to the surface's exposure to another dischargin~ means, an unacceptable condition known as "masking" occurs. This phenomenon results from blast medium covering the surface of the board and then being hit by subsequently thrown blast medium. The effect is lower relative abrasion from the second discharging means and, even when abrasion is e~ident, the character of the abrasion changes such that the texture of the masked area appears different from surrounding areas when painted, presenting an undesirably variable appearance.
A blower means disposed between the first and second abrasive discharging means removes from the board surface the spent abrasive particles thrown by the formex means before exposure of the surface to the second abrasive discharging means. The blower means advantageously comprises a r~of mounted device whic~ supplies air under pressure to blow the spent abrasive off the board surface.
As illustrated in FIGS. 2 to 4, air under pressure is directed from a suitable source, not shown, to a manifold 2L1, whereby air is directed downwardly at an angle of less than 90 to gently sweep the abrasive material from the surface. The air manifold may, for example, consist of a compressed air knife or a manifold connected to a centrifugal blower. In a preferred embodiment, the air is directed angularly downwardly onto the ~iberboard to blow the abrasive particles laterally outwardly from its surface whereby the particles are displaced laterally beyond the board where they can settle downwardly for return by any suita~le means to the chamber supplying the blast wheels to again be used. An especially suitable ~i 13 0 2 C~ ", ` ` ' 1 PATF.~;IT
11/ 0 3 / ~ 9 3 r.~ ~.3 ~
devlce Eor supplying air is the FIG. 4 em~odiment comprising an elongated pipe 24 having a slit and mounted in housing 20 to extend above the production line and from side to side thereof.
A final blow-off device, not shown, is lQcated within housing 20 ~o remove residual abrasive material before conventional finishing of the boards.
From the above description it is seen that the present invention provides a method and apparatus whereby Ei~erboard surfaces may be rapidly and economically textured. In addition, the invention is seen to provide a method and apparatus for texturing fiberboard with a~rasive particles by which method and apparatus the surface of the iberboard may be uniformly and decoratively abraded without complications from spent abrasive on -the board surface. Previous attempts to remove the spent abrasive from the fiberboard surface by employing wipers made of rubber or similar material were unacceptable. The dragging of these wipers across the abraded surface to scrape off used blast medium left marks on the fiberboard and resulted in product reje~ts.
The present invention is further illustrated by the following example in which all percentages are by weight.
EXAMPLE
This example illustrates with reference to the drawings the productlon of textured -fiberboard in accordance with the present invention.
The formulation utilized in manufacturing the product consists of the following ingredients in the listed percentages by weight:
Ingredient g Mineral Wool 65.0 Perlite 21.5 Newsprint 4.0 Starch 9.5 Retention Aid ~.05 The ingredients were diluted with water to form a slurry in machine chest 1. Wet mixing of the slurry, 11/03/89 10 2 ~ ? ~
~hich hacl a stock consistency oE 7 wt. %, nodulated the mineral wvol. The slurry was transformed to head box 5 and next deposited on Fourdriniex wire 7. The slurry was dewatered in a conventional manncr on the Fourdrinier machine to form a wet felt or mat of interlocked fibers.
The partially dewatered fibrous ma-t was next passed through a press section comprising pressing roJls 11, which densified the mat and provided a wet mat of uniEorm thickness labout one inch) with a moisture content of about 65~. After leaving the press section~ the wet mat was conveyed to dryer 12.
After being dried, the board product was subjected to various conventional -finishing steps, which included cutting into appropriate sizes and cleaning. After being flipped over by inverter 18, the board product was then abraded on the screen side by wheel blaster 17 and this side was coated to produce textured fiberboards of the invention.
Texturing of the boards was accomplished under the following conditions:
Line Speed 160 l~pm Wheel Speed 2400 ~ 260Q rp~
Wheel Load 18~ ps Board Thickness Removal 0.030" - 0O040"
Board products made in accordance with the foregoing procedure had the following average physical properties:
Thickness, in. 0.700 - 0.750 Density, lb/cu.ft. 14.0 - 15.5 Transverse Strength, lb 19.0 - 25.0 NRC .60 - .70
More partic-ularly, the present invention provides an apparatus for applying particulate material to the sl1rface of a fiberboard to be provided with a decorative pattern comprising:
(a) a closed housing having entry and exit slots for the fiberboard;
(b) means for conveying the fiberboard to be treated throug~ sai.d housing in a horizontal pos.ition;
(c) a first abrasive discharging means disposed within the housing above the surface of the fiberboard to be treated for applying particulate material to the surface thereofi ~ d) a blower means for removing spent particulate material collected on the surface of the fiberboard after discharge from the first. abrasive discharging means; and (e) a second abrasive discharging means disposed within the housing above the surface of the flberboard for further treatment of the surfac~ with particulate material.
The first and second abrasive dischar~ing means each advantageously comprise at least one centrifugal ~lasting wheel mounted in the roof of the housing to cause a portion of the fiberhoard surface to be uniformly impacted. The second discharging means is located downstream along the produc~ion line from the first such means in order to abrade the remaining fiberboard surface untreated by said first means. Air blown from a device such as an air knife removes spent particulate material left on the surface after its abrasion by the first discharging means. This removal allows the production of a highly decorative and uniform pattern on the surface of the fiberboard, DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the accompanying drawings in which:
E> 13 0 2 3~;9r:['ENT
L~JO~19 4 ?
FIC7. 1 is a diagrammatic, side elevational view o~ an a~paratus for carryillg out the method of the present in-~ention;
FIG. 2 is an enlarged cross-sectional view of the ~h~el blast machine shown in PIG. 1;
FIG. 3 is an enlarged top view of the wheel blast machine shown in FIG. 2, with certain parts being broken away for clarity; and FIG. 4 is an enlargcd perspective view of an air knife for rcmoving abrasive particles.
D:ETAILE.D DE~SCRI~TION OF T~IE INV~NTION
In carrying out the invention, a fiberboard sheet material, which may comprise inorganic and/or organic fibrous material and preferably consists of mineral fibers, a binder and the other board-forming ingredients, is produced in a conventional manner, such as on a wet board forming machine, e.g., a Fourdrinier or a cylinder machine. Referring now to FIG . 1, there is shown a machine chest 1 containing water to which the mineral fibers, such as conventionally felted mineral wool, are first added. Then the other ingredients, which advantageously consist o aqueous suspensions of perlite and optionally clay, oi starch, and of paper, are added to the machine chest. The machine chest agitator 2 is suitably operated to keep the slurry stirred up so that the ingredients are uniformly distributed throughout the slurry. The solids content of the slurry may be from about 2 to 8 we~ght r~ ~
In an advantageous embodiment of the invention, the fiberboard is produced from a slurry con~aining mineral fibers (e.g., mineral wool) which are nodulated during wet mixing of the slurry's ingredients~ To bring about substantial formation of nodulated wool upon mixing of the slurry, the consistency must be sufficiently high~ e.~.~
about 5 to 8, preferably 5.5 to 8, and more preferably 6 to 7.5 weight %. The formation of nodules of mineral fiber during mixing of the slurry may be brought about as desctibed in U. S. patent application Serial No. 210,446, 1302 ~;~$~,5~ 3 PAT~NT
11/03j39 5 f~ f~l f il ed June 23, 1988, the disclosure of which application is hereby lncorporated by rcference. The rate and duration of a~itation for forming an appropriate content of nodulated wool in the slurry can be readily determined through routine experimentation. Generally, the slurry is mixed for about 10 to 60 minutes by means of a rotary ayita-tor (impeller) revolving at a rate oE about 100 to 150 reYolutions per minute. Alternatively, the mineral wool may be introduced to the slurry in the form of pellets of previously nodulated mineral wool.
A~ter the slurry is agitated sufficiently to uniformly distribute the solids and, when appropriate, to nodulate the wool, the slurried composition is transferred by pump 3 through pipe 4 to head box 5. The slurry is subsequently deposited on Fourdrinier wire 7 through orifice 6 of head box 5. The first section 8 of the Fourdrinier wire permits free drainage of water from the material and urther draina~e is promoted by suction boxes 9 in section 10. As the slurry is brought in contact with the Fourdrinier machine and water of the slurry drains therefrom, a wet felted mat o~ the mineral fiber composition forms on the machine. The wet laid mat is dewatered by the Fourdrinier machine ~o a solids content ~f about 20 to 40 weight percent~
The partially dried material is then prepressed to a thickness of about 0.4 to 0.8 inch by a plurality of press rolls 11. It will be appreciated that a single set of press rolls could be employed i~ desired. After being pressed, the sheet product will generally have from about 60 to about 75% water. A coating may be applied to the pressed mat by means of feed-pipe 13 and coater 14.
After passing through press rolls 11, the wet mat is transferred into dryer 12. At the ou-tlet of the dryer, there is ob-~ained a board 15 having a moisture content of about 1.0%. The board is cut into smaller panels by saw arrangement 16. Dried boards having widths of 24 in. or more, e.g., 24 to 52 in.~ can be formed for texturing by the wheel blast machine o~ the invention. The dried 1302 r~TENT
11/03/89 6 ~ s~
product can he subjected to any suitable conventional finishing apparatus, depending on the applications for which it is in~ended. Such apparatuses may include applicators for applying coatings to protect and/or decorate the product surface, such as bevel coaters, finish spray coaters, printers, multi-color decorative coaLers, and the like, and further dr-,7ing equipment.
A fine-textured appearance is created on one of the two major surfaces of ~he dried board by the wheel blaster 17 of -the inven-tion. The board may be advantageously turned over by an inverter 18 to present the smooth scre~n side for surface treatment. The board is continuously passed by suitable conveyor means (e.g., conveyor rollers 19) through the wheel blast machine located on the production line. The housing 2~ of the machine has inlet and outlet openings 25 and 26 for the board. The process can be run at a line speed ol up to 200 lineal ~eet per minute. However, for optimum pattern uniformity, the line speed through the wheel blast machine generally should be about 150-180 lfpm. It is, of course, understood that the speed of the line can be readily adjusted so that the entire board surface will be uniformly subjected to the action of the abrasive spray from the wheel blaster. Even at quite high line speeds, the present invention makes it possible to produce pleasing and uniform patterns on boards which are much wider than conventionally textured boards. Whereas a typical width of a conventionally tex~ured board is about 2 ft., boards having widths up to 52 in. or more can be readily textured in accordance with the prPsent invention.
Referring now to FIGS. 2 and 3, it will be seen that conveyor rollers 19 carry fibrous board 15 khrough the housing 20 of the wheel blast machine to abrade and thereby decoratively texture the board surface with abrasive material 21 propelled by first abrasive discharging means 22. The first abrasive discharging means advantageously comprises one or more roof mounted centrifugal blasting wheels 22 located wlthin the blasting 1302 n PATENT
1~/0~/~9 7 ~d ~ 7,:~ ~J' ~ I 'd 1~
chamber directly above the conveyor means Eor dlrecting the abrasive material downwardly upon the board as it passes -through the chamber. When more than one blasting wheel is employed, such as the two shown in FIGS. 2 and 3, the wheels 22a, 22l~ preferably are staggered in a longi-tudinally spaced apart relation and in a laterally spaced apart relation to cause the top surface of the board to be uniformly impacted by the abrasive particles centrifugally thrown by the wheels, preferably at an acute angle with respect to said board surface. The desired effect of the spacing is that abrasive thrown by the first wheel onto the board will ricochet without passing through the path of abrasive particles thrown by the next wheel thereby to minimize interferences with the particles thrown at the surfaces of the boards and also to avoid undesirable cushioning effects. Wheels 22a, 22b are advantageously located so as to abrade the outer edges of the board.
The machine includes a second abrasive discharging means located within the blasting chamber downstream from the first such means. The second abrasive discharging means advantageously comprises one or more roof mounted centrifugal wheels 23 ~two shown in FIGS. ~ and 3) similarly spaced for uniform treatment and texturing of the board surface. Wheels 23a, 23b are suitably mounted to ~reat the interior portion of the board. The ~hrowing wheels may be of conventi~nal type described in the art, and can be obtained from ~7heelabrator-Frye, Inc.
The surface-treating material 21 may be ~ny abrasive capable of texturing the surface of the board. Both "heavy" abrasives (e.g., metal grit or shot) and "light"
abrasives, which are of softer materials than the former type, may be used. "Light" abrasives include such items as glass shot, plastics, walnut shells, pecan shells, corn husks, peach pits, etc. Typically, the surface abrasion removes about 0.01-0.04, preferably .025 - .035, inch of the board surface in producing the desired look.
~epending on factors such as the type of abrasive and 11~03/89 8 ~ ?~ T~
board being treated as well as the spatial relationshlp o-E
th~ wheels and board, the wheels can be operated at various speeds, such as from about 1800 to 3600 rpm.
~ bLasive granules thrown by the first discharg:ing means against the upper surface o-f board 15 rebound therefrom and collect lnside cabinet 20 and disadvantage-ously on the board surface. If this spent blast medium is not removed from the surface of the board prlor to the surface's exposure to another dischargin~ means, an unacceptable condition known as "masking" occurs. This phenomenon results from blast medium covering the surface of the board and then being hit by subsequently thrown blast medium. The effect is lower relative abrasion from the second discharging means and, even when abrasion is e~ident, the character of the abrasion changes such that the texture of the masked area appears different from surrounding areas when painted, presenting an undesirably variable appearance.
A blower means disposed between the first and second abrasive discharging means removes from the board surface the spent abrasive particles thrown by the formex means before exposure of the surface to the second abrasive discharging means. The blower means advantageously comprises a r~of mounted device whic~ supplies air under pressure to blow the spent abrasive off the board surface.
As illustrated in FIGS. 2 to 4, air under pressure is directed from a suitable source, not shown, to a manifold 2L1, whereby air is directed downwardly at an angle of less than 90 to gently sweep the abrasive material from the surface. The air manifold may, for example, consist of a compressed air knife or a manifold connected to a centrifugal blower. In a preferred embodiment, the air is directed angularly downwardly onto the ~iberboard to blow the abrasive particles laterally outwardly from its surface whereby the particles are displaced laterally beyond the board where they can settle downwardly for return by any suita~le means to the chamber supplying the blast wheels to again be used. An especially suitable ~i 13 0 2 C~ ", ` ` ' 1 PATF.~;IT
11/ 0 3 / ~ 9 3 r.~ ~.3 ~
devlce Eor supplying air is the FIG. 4 em~odiment comprising an elongated pipe 24 having a slit and mounted in housing 20 to extend above the production line and from side to side thereof.
A final blow-off device, not shown, is lQcated within housing 20 ~o remove residual abrasive material before conventional finishing of the boards.
From the above description it is seen that the present invention provides a method and apparatus whereby Ei~erboard surfaces may be rapidly and economically textured. In addition, the invention is seen to provide a method and apparatus for texturing fiberboard with a~rasive particles by which method and apparatus the surface of the iberboard may be uniformly and decoratively abraded without complications from spent abrasive on -the board surface. Previous attempts to remove the spent abrasive from the fiberboard surface by employing wipers made of rubber or similar material were unacceptable. The dragging of these wipers across the abraded surface to scrape off used blast medium left marks on the fiberboard and resulted in product reje~ts.
The present invention is further illustrated by the following example in which all percentages are by weight.
EXAMPLE
This example illustrates with reference to the drawings the productlon of textured -fiberboard in accordance with the present invention.
The formulation utilized in manufacturing the product consists of the following ingredients in the listed percentages by weight:
Ingredient g Mineral Wool 65.0 Perlite 21.5 Newsprint 4.0 Starch 9.5 Retention Aid ~.05 The ingredients were diluted with water to form a slurry in machine chest 1. Wet mixing of the slurry, 11/03/89 10 2 ~ ? ~
~hich hacl a stock consistency oE 7 wt. %, nodulated the mineral wvol. The slurry was transformed to head box 5 and next deposited on Fourdriniex wire 7. The slurry was dewatered in a conventional manncr on the Fourdrinier machine to form a wet felt or mat of interlocked fibers.
The partially dewatered fibrous ma-t was next passed through a press section comprising pressing roJls 11, which densified the mat and provided a wet mat of uniEorm thickness labout one inch) with a moisture content of about 65~. After leaving the press section~ the wet mat was conveyed to dryer 12.
After being dried, the board product was subjected to various conventional -finishing steps, which included cutting into appropriate sizes and cleaning. After being flipped over by inverter 18, the board product was then abraded on the screen side by wheel blaster 17 and this side was coated to produce textured fiberboards of the invention.
Texturing of the boards was accomplished under the following conditions:
Line Speed 160 l~pm Wheel Speed 2400 ~ 260Q rp~
Wheel Load 18~ ps Board Thickness Removal 0.030" - 0O040"
Board products made in accordance with the foregoing procedure had the following average physical properties:
Thickness, in. 0.700 - 0.750 Density, lb/cu.ft. 14.0 - 15.5 Transverse Strength, lb 19.0 - 25.0 NRC .60 - .70
Claims (21)
1. A method of decoratively texturing the surface of a fiberboard which comprises:
(a) conveying the fiberboard in a horizontal position through a closed housing having entry and exit slots for the fiberboard, and (b) decoratively texturing the top surface of the fiberboard while the fiberboard is within the housing by:
(i) discharging particulate material downwardly against a region of the surface of the fiberboard to abrade the surface, a portion of the spent particulate material thereby being deposited on the surface of the fiberboard, (ii) blowing the spent particulate material off the surface, and (iii) discharging additional particulate material downwardly against the surface to complete the abrasion, whereby removal of the spent particulate material from the first discharge prevents masking of the surface and contributes to the formation of a decorative and uniform pattern over the entire fiberboard surface.
(a) conveying the fiberboard in a horizontal position through a closed housing having entry and exit slots for the fiberboard, and (b) decoratively texturing the top surface of the fiberboard while the fiberboard is within the housing by:
(i) discharging particulate material downwardly against a region of the surface of the fiberboard to abrade the surface, a portion of the spent particulate material thereby being deposited on the surface of the fiberboard, (ii) blowing the spent particulate material off the surface, and (iii) discharging additional particulate material downwardly against the surface to complete the abrasion, whereby removal of the spent particulate material from the first discharge prevents masking of the surface and contributes to the formation of a decorative and uniform pattern over the entire fiberboard surface.
2. The method of claim 1 wherein the spent particulate material is blown off the surface of the fiberboard by air directed angularly downwardly onto the fiberboard.
3. The method of claim 1 wherein the fiberboard is conveyed through the housing at a speed of about 150 to 180 lineal feet per minute.
4. The method of claim 3 wherein the fiberboard has a width of about 24 inches to 52 inches.
5. The method of claim 1 wherein the particulate material in step (b)(i) is thrown by at least one first centrifugal blasting wheel mounted in the roof of the housing to cause a portion of the surface to be uniformly impacted, and the particulate material in step (b)(iii) is thrown by at least one second centrifugal blasting wheel mounted in the roof of the housing downstream from the first wheel or wheels to cause the remaining untreated surface to be uniformly impacted.
6. The method of claim 5 wherein the spent particulate material is blown off the surface of the fiberboard by air directed angularly downwardly onto the fiberboard.
7. The method of claim 6 wherein the fiberboard whose surface is to be textured is formed by a wet process comprising depositing a water slurry of the board-forming ingredients upon a moving wire screen for drainage therefrom of water to form a wet felt, and consolidating and drying the wet felt.
8. The method of claim 1 wherein the particulate material in step (b)(i) is thrown by a first pair of centrifugal blasting wheels mounted in the roof of the housing and staggered in a longitudinally spaced apart relation and in a laterally spaced apart relation to cause regions at the outer edges of the surface to be uniformly impacted, and the particulate material in step (b)(iii) is thrown by a second pair of centrifugal blasting wheels mounted in the roof of the housing downstream from the first pair and staggered in a longitudinally spaced apart relation and in a laterally spaced apart relation to cause the interior region of the surface to be uniformly impacted.
9. The method of claim 8 wherein the particulate material is a member selected from the group consisting of glass shot, plastics, metal shot or grit, walnut shells, pecan shells, corn husks, and peach pits.
10. The method of claim 8 wherein the spent particulate material is blown off the surface of the fiberboard by air directed angularly downwardly onto the fiberboard.
11. The method of claim 10 wherein the air is directed angularly downwardly from an air knife.
12. The method of claim 3 wherein the fiberboard is conveyed through the housing at a speed of about 150 to 180 lineal feet per minute.
13. The method of claim 12 wherein the fiberboard has a width of about 24 inches to 52 inches.
14. The method of claim 13 wherein the spent particulate material is blown off the surface of the fiberboard by air directed angularly downwardly onto the fiberboard from an air knife.
15. An apparatus for decoratively texturing the surface of a fiberboard which comprises:
(a) a housing having entry and exit slots for fiberboard;
(b) means for continuously conveying fiberboard to be decoratively textured through the housing;
(c) a first means for discharging particulate material in the housing against a region of the surface of the fiberboard to abrade the surface;
(d) a means for directing an air stream in the housing to remove from the fiberboard surface spent particulate material from the first discharging means; and (e) a second means for discharging particulate material in the housing against the fiberboard surface to complete the decorative texturing, whereby removal of the spent particulate material from the first discharging means prevents masking of the surface and contributes to the formation of a decorative and uniform pattern over the entire fiberboard surface.
(a) a housing having entry and exit slots for fiberboard;
(b) means for continuously conveying fiberboard to be decoratively textured through the housing;
(c) a first means for discharging particulate material in the housing against a region of the surface of the fiberboard to abrade the surface;
(d) a means for directing an air stream in the housing to remove from the fiberboard surface spent particulate material from the first discharging means; and (e) a second means for discharging particulate material in the housing against the fiberboard surface to complete the decorative texturing, whereby removal of the spent particulate material from the first discharging means prevents masking of the surface and contributes to the formation of a decorative and uniform pattern over the entire fiberboard surface.
16. The apparatus of claim 15 wherein the first discharging means comprises at least one first centrifugal blasting wheel mounted in the roof of the housing to cause a portion of the surface to be uniformly impacted, and the second discharging means comprises at least one second centrifugal blasting wheel mounted in the roof of the housing downstream from the first wheel or wheels to cause the remaining untreated surface to be uniformly impacted.
17. The apparatus of claim 16 wherein the means for directing an air stream comprises a device located in the housing above the conveying means for supplying air under pressure angularly downwardly onto the fiberboard to sweep the spent particulate material therefrom.
18. The apparatus of claim 15 wherein the first discharging means comprises a first pair of centrifugal blasting wheels mounted in the roof of the housing and staggered in a longitudinally spaced apart relation and in a laterally spaced apart relation to cause regions at the outer edges of the surface to be uniformly impacted, and the second discharging means comprises a second pair of centrifugal blasting wheels mounted in the roof of the housing downstream from the first pair and staggered in a longitudinally spaced apart relation and in a laterally spaced apart relation to cause the interior region of the surface to be uniformly impacted.
19. The apparatus of claim 18 wherein the means for directing an air stream comprises a device located in the housing above the conveying means for supplying air under pressure angularly downwardly onto the fiberboard to sweep the spent particulate material therefrom.
20. The apparatus of claim 19 wherein the means for directing an air stream comprises an air knife.
21. The apparatus of claim 19 wherein the particulate material comprises a member selected from the group consisting of glass shot, plastics, metal shot or grit, walnut shells, pecan shells, corn husks, and peach pits.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US43381389A | 1989-11-09 | 1989-11-09 | |
| US07/433,813 | 1989-11-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2029072A1 true CA2029072A1 (en) | 1991-05-10 |
Family
ID=23721620
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2029072 Abandoned CA2029072A1 (en) | 1989-11-09 | 1990-10-31 | Texturing of acoustical mineral fiberboard with wheel blast machine |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0427274A1 (en) |
| CA (1) | CA2029072A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL1015092C2 (en) * | 2000-05-02 | 2001-11-05 | Constructiewerkplaats G C Gr N | Bi-directional shot-blasting and paint spraying plant enables material to be blasted but not sprayed to be fed through in reverse direction from normal |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2434736A (en) * | 1941-03-05 | 1948-01-20 | Certain Teed Prod Corp | Apparatus for surfacing sheet material |
| GB851021A (en) * | 1957-04-25 | 1960-10-12 | Lawes Bros Ltd | Process for providing plastics material with a matt surface |
| GB898172A (en) * | 1960-01-27 | 1962-06-06 | Henry Cobden Turner | Improvements in or relating to the treatment of leather or plastic articles |
| CH374565A (en) * | 1960-01-29 | 1964-01-15 | Fischer Ag Georg | Centrifugal cleaning machine, especially for blasting strip-shaped cleaning items |
| US3269066A (en) * | 1963-01-09 | 1966-08-30 | Wheelabrator Corp | Method for production of abraded design on work surfaces |
| CH447864A (en) * | 1966-02-14 | 1967-11-30 | Fischer Ag Georg | Centrifugal cleaning machine for blasting semi-finished products, in particular rolled goods, e.g. Sheets and strips of iron |
| US3832809A (en) * | 1972-01-05 | 1974-09-03 | Carborundum Co | Method for removing wustite scale |
| CA1213768A (en) * | 1982-11-08 | 1986-11-12 | Celotex Corporation (The) | Wet-end molding method and molded product |
| US4911788A (en) * | 1988-06-23 | 1990-03-27 | The Celotex Corporation | Method of wet-forming mineral fiberboard with formation of fiber nodules |
-
1990
- 1990-10-31 CA CA 2029072 patent/CA2029072A1/en not_active Abandoned
- 1990-11-08 EP EP90121427A patent/EP0427274A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| EP0427274A1 (en) | 1991-05-15 |
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