CA1176423A - Apparatus for laying a mat of wood strands - Google Patents
Apparatus for laying a mat of wood strandsInfo
- Publication number
- CA1176423A CA1176423A CA000412025A CA412025A CA1176423A CA 1176423 A CA1176423 A CA 1176423A CA 000412025 A CA000412025 A CA 000412025A CA 412025 A CA412025 A CA 412025A CA 1176423 A CA1176423 A CA 1176423A
- Authority
- CA
- Canada
- Prior art keywords
- rolls
- strands
- pile
- spike
- spreader
- 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
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
- E04C2/02—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials
- E04C2/10—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products
- E04C2/16—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products of fibres, chips, vegetable stems, or the like
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/08—Moulding or pressing
- B27N3/10—Moulding of mats
- B27N3/14—Distributing or orienting the particles or fibres
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Architecture (AREA)
- Manufacturing & Machinery (AREA)
- Forests & Forestry (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Dry Formation Of Fiberboard And The Like (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An apparatus for laying a mat of wood strands, particularly long strands, in the process of producing a composite product such as waferboard is disclosed. In the past it has not been possible to lay long wafers in an oriented mat except by hand. The present invention provides a means for forming a pile of wood strands of substantially uniform depth, a plurality of spike rolls located at one side of the pile of wood strands to pull the wood strands out of the pile and form a uniform curtain of falling strands and a conveyor to force the pile of wood strands against the spike rolls. Beneath the spike rolls are a pair of counter-rotating spreader rolls spaced apart to receive the curtain of strands and having spikes to distribute the strands in an even mat beneath. A horizontal adjustment is provided to position the spreader rolls beneath the curtain and vary the distance between the rolls.
An apparatus for laying a mat of wood strands, particularly long strands, in the process of producing a composite product such as waferboard is disclosed. In the past it has not been possible to lay long wafers in an oriented mat except by hand. The present invention provides a means for forming a pile of wood strands of substantially uniform depth, a plurality of spike rolls located at one side of the pile of wood strands to pull the wood strands out of the pile and form a uniform curtain of falling strands and a conveyor to force the pile of wood strands against the spike rolls. Beneath the spike rolls are a pair of counter-rotating spreader rolls spaced apart to receive the curtain of strands and having spikes to distribute the strands in an even mat beneath. A horizontal adjustment is provided to position the spreader rolls beneath the curtain and vary the distance between the rolls.
Description
APPARATUS FOR LAYING A MAT OF WOOD STRANDS
This Invention relatss to the manufacture of a composite produci- of wood strands such as waferboard.
Most specifically the Invention provldes an apparatus for laylng wood strands In a mat of uniform th1ckness.
The term wood strands includes wood wafers, flakes, partlcles and chlps havlng a length equal to or greater than the width, and havlng a thlckness not greater than 3 mm (1/8 Inch). Wood strands for compo-slte panelboards are generally made In lengths of from 12 mm (1/2 inch) to 76 mm t3 Inch) widths of up to 38mm (1-1/2 Inch) and a thlckness not greater than 3 mm.
In the preparatlon of waferboard, wood wafers are first blended wlth resln and wax and then lald 1n a mat of unlform thlckness on an advanclng conveyor whlch conveys the mat to a hot press for curlng the resln to make a waferboard product. The wafers are generally lald In several layers one on top of the other. in some cases certaln layers have ~he strands orlented.
In one case the two outer layers have the strands orl en-i-ed In -i-he lengthwlse directlon of the board and the Inner layers hava the strands randomly orlented. Other types of waferboard have the strands orlented along the length of the board In some layers and across the width of the hoard In other layers.
~L7~2~3 At the present time, the maximum length of wafers In the preparatlon of waferboard has been not greater than 76 mm (3 inch)~ However, there is con-sideratlon today of produclng a waferboard wlth wafer lengths of 305 mm (12 Tnch) or longer. Such a board has greater strongth propertles than exlsting waferboard.
Waferboard utillzes more of a tree than plywood and thus Is a more efflclent use of wood. Furthermore, the wa1ght of waferboard ~ade from long wafers 1s substan-t1a11y the same as the we1ght of a plywood havlng equlvalent strength properties.
Although the applicat1on is prlmar11y con-cerned w1th warerboard, other types of wood strands may be used w1th the apparatus of ths present Invention.
The composlte product may 1nc1ude external veneer sheets w1th wood strands 1n between, the wood strands may be la1d tn an orlented pat~ern.
It is the purpose of the present lnventlon to provlde an apparatus for 1ay1ng wood strands up to at least 305 mm 1n length In a mat of substant1ally unl-form th1ckness. The wood strands may ba lald In an orlented pattern or In a random pattern, The apparatus spreads the wood strands In a unlform manner to provIde a mat havlng substantlally even thlckness.
The present Inventlon provldes an apparatus for contlnuously laylng wood strands In a mat of sub-stant1ally even thlckness, the mat advanc1ng at a substantlally constant speed, comprlslng means for formlng a plle of wood strands of substantlally uni~orm depth, a plurallty of splke rolls rotatlng about sub-stantlally horizontal, parallel axes spaced vertlcally apart and located at one slde of the plle of wood strands, the splke rolls adapted to pull wood strands out of the plle and form a unlform curtaIn of falllng strands, advancing means for the pile of wood strands to force the plle agalnst the spike rolls, a palr of counter-rotating spreader rolls, side by slde In the same horizontai plane, -ihe spreader rolls havlng axes substantially parallel to the spike ro r I axes and located beneath the splke rolls to recelve the curtain of fallTng strands, each of the spreader rolls havlng a plurallty of radlally extendlng spTkes to dlstrlbute the strands evenly In a mat beneath, and horlzontal adjustment méans for the spreader rolls to adjust the locatton of the spreader rolls beneath the curtain of falllng strands, and provlde a predetermlned dlstance between tlps of the splkes on one spreader roll and tlps of the splkes on the other spreader roll.
In a preferred embodlment the means for form-lng the plle of wood strands Includes a rake back conveyor located at the top of the pile to convey wood strands at the top of the plle away from the splke rolls, and wher01n the advanclng means Includes a conveyor at the bottom of the plle to advance the plle towards the splke rolls. The splke rolls are prefer-ably located between the rake back conveyor at the top of the plle of wood strands and the conveyor at the bottom of the plle, the axes of the splke rolls are In a substantlally stralght llne sloplng upwards towards the rake back conveyor. The preferred angle of slope is in the range of about 55 to 60 degrees to the horl-zontal.
In another embodlment an orlentlng means Is located baneath the spreader rolls and above the mat to provlde an orientatlon of strands In the mat. In one embodtment the spike rolls adjacent to each other have splkes wh}ch intermesh and overlap, or alternatlvely the spikes are In Itne9 and a space Is provlded between tlps of the splkes on one spike roll and tlps of the splkes on the adjacent spike roll~ The spikes on the splke rolls and on the separatlng rolls, In one embodlment are formed from flat strlps havlng a rectangular cross-sectlon.
In drawings which illustrate embodlments of the Invent5On - Flgure 1 is a slde elevatlon showlng one embodlment of an apparatus for laylng a mat of wood strands accordlng to -the present Inventlon.
- Flgures 2 and 3 are schematlc partial elevatlons showlng different conflguratlons of the arrangement of splkes on adjacent splke rolls.
- Flgure 4 Is a partlal Isometric vlew of a splke roll or a spreader roll havlng one type of splkeO
~71~2~
Referrlng now to the Flgure 1, th0 formlng apparatus lO has a bin 11 with a top entrance 12~ The wood strands pass through the top entrance 12 to form a plle 13 whlch rests on an apron conveyor belt 14. When the strands enter the bin 11 they pass through a rake back conveyor 15 whlch rakes the top of the plle 13 backwards in such a manner that the level of the pile Is maintalned at substan-tlally the same helght as it advances on the apron belt 14. The rake back conveyor 15 moves wood strands backwards and the apron belt 14 moves the plle 13 forwards.
At the end of the apron belt 14 and between the apron belt 14 and the rake back conveyor 15 are a pluralIty of spike rolls 16. The spike rolls 16 have horizontal parallel axes whlch extend In a substantl-31 Iy straight line sloping backwards towards the rake back conveyor 15. The dlstance between each splke roll Is sutflclent so that radial spikes 17 extendTng radi-ally from the splke roll 16 gently puli the strands out of the plle 13 -to meter the flow of strands, and form a unlform curtaln of falllng strands whlch drop onto two spreader rolls 18 located slde by slde In the same horlzon-tal plane, and wlth axes substantlally parallel to the axes of -the splke rolls 16. A space is provlded between the spreader rolls 18, the space belng In the approxlmate center of the curtaln of falllng strands, Some s-trands fall through the space between spreader rolls 1~. The two spreadar rolls 18 are counter rota-tlng so that the ~ood strands that fall on the spreader rolls 18 are thrown outward of each roll 18 and fatl In ~7~
a substantlally even layer to form a mat 19 restlng on a mat conveyor 20. The speed of the apron belt 14 and fhe rota-i-lonal speed of the spike rolls 16 can be in-dependently var1ed to control the flow of strands.
Each of the spreader rolls 18 has a pluralIty of radially extending splkes 21 to aid Tn distrlbutlng the strands In a mat havlng an even th1ckness. As shown in Flgure 1, each of the spreader ro`lls 18 is mounted on a trunnlon block 22 which has a horizontal movement, and a threaded rod 23 and lo~king nut 24 provlde adjustment for each spreader roll so that a predeterm!ned space can be provlded between tips of the splkes 21 on one spreader roll 18 and tips of the sp1kes 2t on the acijacent spreader roll 18. Further-more, the spreader rolls 18 can be positioned an equal distance apar-i- from the centar of the falling curtaln of strandsO The rotatlonal speed of the spreader rolls 18 can be adjusted to ald tn the even distribution of the strands. These adjustments are necessary to take into account different lengths and dimenslons of wood strands belng formed in a mat. The strands fall onto the mai 19 from both sldes of ihe spreader rolls 18 and through the space between the spreader rolls 18.
In one embodlment, an orlentlng devlce Is provlded so that as the strands fall from the spreader rolls 18, they are orlented elther In the longltudlnal dlrectlon of the movlng mat or crosswise across the mat. There are varlous types of orlentlng devlces sultable for orlentlng strands. Such devlces Include rotatlng discs, vlbratlng plates and eiectrostatic orlenting systems.
In one partlcular orlentlng devlce, a serles of plates 30 are hung vertlcally by wlres or cables 31 In line and spaced across the mat conveyor 20 to form an orlenting grld. The spacing of the plates 30 is de-pendent on the size of the wood strands. The elevation of every other plate 30 is hlgher than the adjacent plate to avoid the strands brldglng across the plates 30 and a vlbratlng mechanlsm 32 vlbrates the plates 30 as they hang from the strands 31 to ensure that strands do not get hung up on the plates when falllng from the spreader rolls 18.
In operation, wood strands drop through the rake back conveyor 15 into the bln 11 restlng on the apron belt 14. The helght of the plle 13 Is determlned by rake back conveyor 15 whlch ensures that the plle Is at a substantially even height when advanclng to the splke rolls 16. The apron belt 14 always moves slowly so that the plle 13 is pushed agalnst the splke rolls 16, and the splke rolls then gently pull the wood strands from the plle 13 and meter the flow of strands falllng In a unlform curtaln on and between the spread-er rolls 18. The spreader rolls 18 throw the wood strands on elther slde where, If an orlentlng devlce Is provlded, the strands are orlented and then lald onto a mat 19 on a mat conveyor 20. The mat conveyor 20 Is contlnuously movlng and the mat 19 Is formed wlth a substantlally unlform or even thlckness. Flgure 1 11-lustrates the mat 19 being lald directly on a conveyor~O. However, If several layers are formed, the mat can be laid dlrectly on a prevlous mat.
Figure 2 illustrates two adjacent spike rolls 16 wlth splkes 17 In line, A space is provlded between tips of the spikes 17 on one spike roll 16 and tips of the splkes 17 In the adjacent sptke roll 16. Flgure 3 illustrates two adJacent splke rolls 16 wlth splkes 17 Intermeshed so that the sptkes 17 on one spike roll 16 overlap the splkes 17 on the adjacent roll; It has b0en found that for long wafers less breakage occurs In the wafers when the splkes 17 are arranged in line, however a better coefficient of variatlon in the resulting mat 19 occurs when the splkes 17 are intermeshed. In as much as there Is no overlapplng of the splkes 22 In the two spreader rolls 18, it does not matter if the splkss In one roll are In line or In between the splkes on the other roll.
One type of roll, either splke roll 16 or spreader roll 18 Is shown in Flgure 4 wherein a roll 40, mounted on a shaft 41 has a serles of splkes 42 whlch are formed from flat strlps having a ractangular cross-s~ct!on wlth th0 flat face in llne wlth the roll axls. The flat splkes 42 are attached to the face of the roll 40~ One method of attachlng the splkes 42 to the roll 40 Is by angle sectlons 43 extended axlally along the face of the rotl. Four, slx or elght splkes 42 may extend radlally around the roll, splkes may ba staggered In radlal extenslons wlth four or six splkes ~7~23 42 In one circumferentlal piane and the same number in an adJacent plane but offset.
Tests were carrled out for formlng a mat in a formlng llne 1.2 meters wide uslng an apparatus similar to that shown In the figure. The strand flow rate waS
set at 45 kgfrnln representlng the strands fed into the bin 11 and the mat conveyor 20 speed was 18.3 m~min.
As shown ln Flgure 1, f1ve splke rolls 16 were provTded and speeds of 110, 180 and 215 rpm ~ere used for the splka rol 1s7 The angle of slope of the sprke roll axes was varled from 55 to 60 d0grees to the horizontai, sloplng back towards the rake back conveyor 15. Spa-clng between the splkes 17 on the splke rolls 16 was 20 cm and the splkes 17 on adjacent splke rolls 16 were Intermeshlng wlth slx rows of splkes per row and an overlap of 7 cm. The diametar of each spike roll 16 was 40 cm and each splke 17 extended 10 cm from the surface of the roll. The splkes 17 were made from flat strlps 2 cm wlde. The spreader rolls 18 were accordlng to tha conflguratlon shown In Flgure 4, tlp to tip of the sptkas 21 was 30 cm wlth the length of each splke 21 7 cm.
When the llne had settled down and was run-nlng contlnuously, a sample collectlon board 1,220 mm long and 1,320 mm wlde was placed on the mat conveyor 20 and run under the formlng apparatus of the present Invent1On. The collectlon board was dlvlded Into ten equal slze compartments S10 x 264 mm for long strands (305 mm) and twenty equal slze compartments 305 x 264 _ 9 _ ~7~ 3 mm for shorter strands (152 mm). After each run the welght of wafers In each compartment was weighed to the nearest .1 of a gram. Four runs of the shorter strands and eight runs of the longer strands were measured for each test condltlon givlng 80 indivldual sample welghts per test condltlon, In the fIrst tests wood strands 305 mm long were run wlth the spreader rolls 18 havlng a separation of 38.1 and 49.5 cm gap between splkes 21. The spreader roll speed was 215 rpm. The spike rolls f6 rotated at 215 rpm also and had a spike roll axes slope angle of 60 degrees. The apron belt speed was 0.6 m~min. After each run the we7ght of wafers In each compartment was welghed to the nearest ~1 of a gram. Elght runs were measured for each test condltion of the long strands glving elghty Indivldual sample welghts'per test c.ondi-tlon. Table I shows the overall mat weight coefflclent .
of varlatlon for elghty measurements and the mean of flve coefficlents of varlation calculated for each of flve columns measured In direction of movement of mat belt 200 TABLE 1.
._ _ ____ Slope of Splke Roll Axes _ . _ , to Horlzontal, degrees 60 60 Splke Roll Speed, rpm 215 215 Spreader Roll Separation, cm 38.1 49.5 Mat CoeffIclent of Varlatlon, %
Overall 14.1 18.2 Along Mat 11.9 10.9 _ _ _ ~7~2~
Slmllar t0sts were run wlth wood strands of 152 mm t6 Inch) In length uslng a collection board wlth 20 equal compartments 305 x 264 mm In slze. Rasults of the tests are shown In Table llo TABLE ll.
__ Slope of Spike Roll Axes _ to Horizontal, degrees 60 60 60 55 Splke Roll Spaed, rpm 180 120 215 215 Spreader Roll Separatlon,cm38.138.1 38.1 38.1 Mat Coefficient of Varlation, %
Overall 18~7 12.611~5 14.8 Along Mat13.3 8.4 9.4 11.2 L
Orientatlon tests wara run with 76 mm grld spaclng with the setup as shown In the figure. The grid was set at a helght of 38 mm above the mat belt 20, measurements were taken after the llne was runnlng contTnuously wlth 152 mm long wood strands belng formed Into a mat. Mean wafer orlentation angle obtained was 8.9 degrees and the orlenting grid was able to hancila the 45 kg/min flow rate of the wood strands in these tests. Thls orlentatlon angle Is consldered to be a hlghly orlented product. Further tests were run wlth 152 mm grld spaclng for wood strands 305 mm In length.
The mean wafer orientatlon angle obtalned was 9 degrees whlch Is consldered a hlghly orlented mat.
Varlous changes may be made to the apparatus shown wlthout departlng from the scope of the present Invantlon which Is llmlted only by the followlng claims
This Invention relatss to the manufacture of a composite produci- of wood strands such as waferboard.
Most specifically the Invention provldes an apparatus for laylng wood strands In a mat of uniform th1ckness.
The term wood strands includes wood wafers, flakes, partlcles and chlps havlng a length equal to or greater than the width, and havlng a thlckness not greater than 3 mm (1/8 Inch). Wood strands for compo-slte panelboards are generally made In lengths of from 12 mm (1/2 inch) to 76 mm t3 Inch) widths of up to 38mm (1-1/2 Inch) and a thlckness not greater than 3 mm.
In the preparatlon of waferboard, wood wafers are first blended wlth resln and wax and then lald 1n a mat of unlform thlckness on an advanclng conveyor whlch conveys the mat to a hot press for curlng the resln to make a waferboard product. The wafers are generally lald In several layers one on top of the other. in some cases certaln layers have ~he strands orlented.
In one case the two outer layers have the strands orl en-i-ed In -i-he lengthwlse directlon of the board and the Inner layers hava the strands randomly orlented. Other types of waferboard have the strands orlented along the length of the board In some layers and across the width of the hoard In other layers.
~L7~2~3 At the present time, the maximum length of wafers In the preparatlon of waferboard has been not greater than 76 mm (3 inch)~ However, there is con-sideratlon today of produclng a waferboard wlth wafer lengths of 305 mm (12 Tnch) or longer. Such a board has greater strongth propertles than exlsting waferboard.
Waferboard utillzes more of a tree than plywood and thus Is a more efflclent use of wood. Furthermore, the wa1ght of waferboard ~ade from long wafers 1s substan-t1a11y the same as the we1ght of a plywood havlng equlvalent strength properties.
Although the applicat1on is prlmar11y con-cerned w1th warerboard, other types of wood strands may be used w1th the apparatus of ths present Invention.
The composlte product may 1nc1ude external veneer sheets w1th wood strands 1n between, the wood strands may be la1d tn an orlented pat~ern.
It is the purpose of the present lnventlon to provlde an apparatus for 1ay1ng wood strands up to at least 305 mm 1n length In a mat of substant1ally unl-form th1ckness. The wood strands may ba lald In an orlented pattern or In a random pattern, The apparatus spreads the wood strands In a unlform manner to provIde a mat havlng substantlally even thlckness.
The present Inventlon provldes an apparatus for contlnuously laylng wood strands In a mat of sub-stant1ally even thlckness, the mat advanc1ng at a substantlally constant speed, comprlslng means for formlng a plle of wood strands of substantlally uni~orm depth, a plurallty of splke rolls rotatlng about sub-stantlally horizontal, parallel axes spaced vertlcally apart and located at one slde of the plle of wood strands, the splke rolls adapted to pull wood strands out of the plle and form a unlform curtaIn of falllng strands, advancing means for the pile of wood strands to force the plle agalnst the spike rolls, a palr of counter-rotating spreader rolls, side by slde In the same horizontai plane, -ihe spreader rolls havlng axes substantially parallel to the spike ro r I axes and located beneath the splke rolls to recelve the curtain of fallTng strands, each of the spreader rolls havlng a plurallty of radlally extendlng spTkes to dlstrlbute the strands evenly In a mat beneath, and horlzontal adjustment méans for the spreader rolls to adjust the locatton of the spreader rolls beneath the curtain of falllng strands, and provlde a predetermlned dlstance between tlps of the splkes on one spreader roll and tlps of the splkes on the other spreader roll.
In a preferred embodlment the means for form-lng the plle of wood strands Includes a rake back conveyor located at the top of the pile to convey wood strands at the top of the plle away from the splke rolls, and wher01n the advanclng means Includes a conveyor at the bottom of the plle to advance the plle towards the splke rolls. The splke rolls are prefer-ably located between the rake back conveyor at the top of the plle of wood strands and the conveyor at the bottom of the plle, the axes of the splke rolls are In a substantlally stralght llne sloplng upwards towards the rake back conveyor. The preferred angle of slope is in the range of about 55 to 60 degrees to the horl-zontal.
In another embodlment an orlentlng means Is located baneath the spreader rolls and above the mat to provlde an orientatlon of strands In the mat. In one embodtment the spike rolls adjacent to each other have splkes wh}ch intermesh and overlap, or alternatlvely the spikes are In Itne9 and a space Is provlded between tlps of the splkes on one spike roll and tlps of the splkes on the adjacent spike roll~ The spikes on the splke rolls and on the separatlng rolls, In one embodlment are formed from flat strlps havlng a rectangular cross-sectlon.
In drawings which illustrate embodlments of the Invent5On - Flgure 1 is a slde elevatlon showlng one embodlment of an apparatus for laylng a mat of wood strands accordlng to -the present Inventlon.
- Flgures 2 and 3 are schematlc partial elevatlons showlng different conflguratlons of the arrangement of splkes on adjacent splke rolls.
- Flgure 4 Is a partlal Isometric vlew of a splke roll or a spreader roll havlng one type of splkeO
~71~2~
Referrlng now to the Flgure 1, th0 formlng apparatus lO has a bin 11 with a top entrance 12~ The wood strands pass through the top entrance 12 to form a plle 13 whlch rests on an apron conveyor belt 14. When the strands enter the bin 11 they pass through a rake back conveyor 15 whlch rakes the top of the plle 13 backwards in such a manner that the level of the pile Is maintalned at substan-tlally the same helght as it advances on the apron belt 14. The rake back conveyor 15 moves wood strands backwards and the apron belt 14 moves the plle 13 forwards.
At the end of the apron belt 14 and between the apron belt 14 and the rake back conveyor 15 are a pluralIty of spike rolls 16. The spike rolls 16 have horizontal parallel axes whlch extend In a substantl-31 Iy straight line sloping backwards towards the rake back conveyor 15. The dlstance between each splke roll Is sutflclent so that radial spikes 17 extendTng radi-ally from the splke roll 16 gently puli the strands out of the plle 13 -to meter the flow of strands, and form a unlform curtaln of falllng strands whlch drop onto two spreader rolls 18 located slde by slde In the same horlzon-tal plane, and wlth axes substantlally parallel to the axes of -the splke rolls 16. A space is provlded between the spreader rolls 18, the space belng In the approxlmate center of the curtaln of falllng strands, Some s-trands fall through the space between spreader rolls 1~. The two spreadar rolls 18 are counter rota-tlng so that the ~ood strands that fall on the spreader rolls 18 are thrown outward of each roll 18 and fatl In ~7~
a substantlally even layer to form a mat 19 restlng on a mat conveyor 20. The speed of the apron belt 14 and fhe rota-i-lonal speed of the spike rolls 16 can be in-dependently var1ed to control the flow of strands.
Each of the spreader rolls 18 has a pluralIty of radially extending splkes 21 to aid Tn distrlbutlng the strands In a mat havlng an even th1ckness. As shown in Flgure 1, each of the spreader ro`lls 18 is mounted on a trunnlon block 22 which has a horizontal movement, and a threaded rod 23 and lo~king nut 24 provlde adjustment for each spreader roll so that a predeterm!ned space can be provlded between tips of the splkes 21 on one spreader roll 18 and tips of the sp1kes 2t on the acijacent spreader roll 18. Further-more, the spreader rolls 18 can be positioned an equal distance apar-i- from the centar of the falling curtaln of strandsO The rotatlonal speed of the spreader rolls 18 can be adjusted to ald tn the even distribution of the strands. These adjustments are necessary to take into account different lengths and dimenslons of wood strands belng formed in a mat. The strands fall onto the mai 19 from both sldes of ihe spreader rolls 18 and through the space between the spreader rolls 18.
In one embodlment, an orlentlng devlce Is provlded so that as the strands fall from the spreader rolls 18, they are orlented elther In the longltudlnal dlrectlon of the movlng mat or crosswise across the mat. There are varlous types of orlentlng devlces sultable for orlentlng strands. Such devlces Include rotatlng discs, vlbratlng plates and eiectrostatic orlenting systems.
In one partlcular orlentlng devlce, a serles of plates 30 are hung vertlcally by wlres or cables 31 In line and spaced across the mat conveyor 20 to form an orlenting grld. The spacing of the plates 30 is de-pendent on the size of the wood strands. The elevation of every other plate 30 is hlgher than the adjacent plate to avoid the strands brldglng across the plates 30 and a vlbratlng mechanlsm 32 vlbrates the plates 30 as they hang from the strands 31 to ensure that strands do not get hung up on the plates when falllng from the spreader rolls 18.
In operation, wood strands drop through the rake back conveyor 15 into the bln 11 restlng on the apron belt 14. The helght of the plle 13 Is determlned by rake back conveyor 15 whlch ensures that the plle Is at a substantially even height when advanclng to the splke rolls 16. The apron belt 14 always moves slowly so that the plle 13 is pushed agalnst the splke rolls 16, and the splke rolls then gently pull the wood strands from the plle 13 and meter the flow of strands falllng In a unlform curtaln on and between the spread-er rolls 18. The spreader rolls 18 throw the wood strands on elther slde where, If an orlentlng devlce Is provlded, the strands are orlented and then lald onto a mat 19 on a mat conveyor 20. The mat conveyor 20 Is contlnuously movlng and the mat 19 Is formed wlth a substantlally unlform or even thlckness. Flgure 1 11-lustrates the mat 19 being lald directly on a conveyor~O. However, If several layers are formed, the mat can be laid dlrectly on a prevlous mat.
Figure 2 illustrates two adjacent spike rolls 16 wlth splkes 17 In line, A space is provlded between tips of the spikes 17 on one spike roll 16 and tips of the splkes 17 In the adjacent sptke roll 16. Flgure 3 illustrates two adJacent splke rolls 16 wlth splkes 17 Intermeshed so that the sptkes 17 on one spike roll 16 overlap the splkes 17 on the adjacent roll; It has b0en found that for long wafers less breakage occurs In the wafers when the splkes 17 are arranged in line, however a better coefficient of variatlon in the resulting mat 19 occurs when the splkes 17 are intermeshed. In as much as there Is no overlapplng of the splkes 22 In the two spreader rolls 18, it does not matter if the splkss In one roll are In line or In between the splkes on the other roll.
One type of roll, either splke roll 16 or spreader roll 18 Is shown in Flgure 4 wherein a roll 40, mounted on a shaft 41 has a serles of splkes 42 whlch are formed from flat strlps having a ractangular cross-s~ct!on wlth th0 flat face in llne wlth the roll axls. The flat splkes 42 are attached to the face of the roll 40~ One method of attachlng the splkes 42 to the roll 40 Is by angle sectlons 43 extended axlally along the face of the rotl. Four, slx or elght splkes 42 may extend radlally around the roll, splkes may ba staggered In radlal extenslons wlth four or six splkes ~7~23 42 In one circumferentlal piane and the same number in an adJacent plane but offset.
Tests were carrled out for formlng a mat in a formlng llne 1.2 meters wide uslng an apparatus similar to that shown In the figure. The strand flow rate waS
set at 45 kgfrnln representlng the strands fed into the bin 11 and the mat conveyor 20 speed was 18.3 m~min.
As shown ln Flgure 1, f1ve splke rolls 16 were provTded and speeds of 110, 180 and 215 rpm ~ere used for the splka rol 1s7 The angle of slope of the sprke roll axes was varled from 55 to 60 d0grees to the horizontai, sloplng back towards the rake back conveyor 15. Spa-clng between the splkes 17 on the splke rolls 16 was 20 cm and the splkes 17 on adjacent splke rolls 16 were Intermeshlng wlth slx rows of splkes per row and an overlap of 7 cm. The diametar of each spike roll 16 was 40 cm and each splke 17 extended 10 cm from the surface of the roll. The splkes 17 were made from flat strlps 2 cm wlde. The spreader rolls 18 were accordlng to tha conflguratlon shown In Flgure 4, tlp to tip of the sptkas 21 was 30 cm wlth the length of each splke 21 7 cm.
When the llne had settled down and was run-nlng contlnuously, a sample collectlon board 1,220 mm long and 1,320 mm wlde was placed on the mat conveyor 20 and run under the formlng apparatus of the present Invent1On. The collectlon board was dlvlded Into ten equal slze compartments S10 x 264 mm for long strands (305 mm) and twenty equal slze compartments 305 x 264 _ 9 _ ~7~ 3 mm for shorter strands (152 mm). After each run the welght of wafers In each compartment was weighed to the nearest .1 of a gram. Four runs of the shorter strands and eight runs of the longer strands were measured for each test condltlon givlng 80 indivldual sample welghts per test condltlon, In the fIrst tests wood strands 305 mm long were run wlth the spreader rolls 18 havlng a separation of 38.1 and 49.5 cm gap between splkes 21. The spreader roll speed was 215 rpm. The spike rolls f6 rotated at 215 rpm also and had a spike roll axes slope angle of 60 degrees. The apron belt speed was 0.6 m~min. After each run the we7ght of wafers In each compartment was welghed to the nearest ~1 of a gram. Elght runs were measured for each test condltion of the long strands glving elghty Indivldual sample welghts'per test c.ondi-tlon. Table I shows the overall mat weight coefflclent .
of varlatlon for elghty measurements and the mean of flve coefficlents of varlation calculated for each of flve columns measured In direction of movement of mat belt 200 TABLE 1.
._ _ ____ Slope of Splke Roll Axes _ . _ , to Horlzontal, degrees 60 60 Splke Roll Speed, rpm 215 215 Spreader Roll Separation, cm 38.1 49.5 Mat CoeffIclent of Varlatlon, %
Overall 14.1 18.2 Along Mat 11.9 10.9 _ _ _ ~7~2~
Slmllar t0sts were run wlth wood strands of 152 mm t6 Inch) In length uslng a collection board wlth 20 equal compartments 305 x 264 mm In slze. Rasults of the tests are shown In Table llo TABLE ll.
__ Slope of Spike Roll Axes _ to Horizontal, degrees 60 60 60 55 Splke Roll Spaed, rpm 180 120 215 215 Spreader Roll Separatlon,cm38.138.1 38.1 38.1 Mat Coefficient of Varlation, %
Overall 18~7 12.611~5 14.8 Along Mat13.3 8.4 9.4 11.2 L
Orientatlon tests wara run with 76 mm grld spaclng with the setup as shown In the figure. The grid was set at a helght of 38 mm above the mat belt 20, measurements were taken after the llne was runnlng contTnuously wlth 152 mm long wood strands belng formed Into a mat. Mean wafer orlentation angle obtained was 8.9 degrees and the orlenting grid was able to hancila the 45 kg/min flow rate of the wood strands in these tests. Thls orlentatlon angle Is consldered to be a hlghly orlented product. Further tests were run wlth 152 mm grld spaclng for wood strands 305 mm In length.
The mean wafer orientatlon angle obtalned was 9 degrees whlch Is consldered a hlghly orlented mat.
Varlous changes may be made to the apparatus shown wlthout departlng from the scope of the present Invantlon which Is llmlted only by the followlng claims
Claims (11)
1. Apparatus for continuously laying wood strands in a mat of substantially even thickness, the mat advancing at a sub-stantially constant speed comprising:
- means for forming a pile of wood strands of substantially uniform depth, - plurality of spike rolls rotating about substantially hor-izontal parallel axes spaced vertically apart and located at one side of the pile of wood strands, the spike rolls adapted to pull wood strands out of the pile, and form a uniform curtain of falling strands, - advancing means for the pile of wood strands to force the pile, against the spike rolls, - a pair of counter-rotating spreader rolls side by side in the same horizontal plane, the spreader rolls having axes substantially parallel to the spike roll axes and located beneath the spike rolls to receive the curtain of falling strands, - each of the spreader rolls having a plurality of radially extending spikes to distribute the strands evenly in a mat beneath, - means to rotate the spreader rolls in counter-rotating directions such that strands distributed by the spikes are directed outside the spreader rolls and not in between and, - horizontal adjustment means for the spreader rolls to adjust the location of the spreader rolls beneath the curtain of falling strands, and provide a predetermined distance between tips of the spikes on one spreader roll and tips of the spikes on the other spreader roll, and ensure that the tips of the spikes on one spreader roll do not overlap with the tips of the spikes on the other spreader roll.
- means for forming a pile of wood strands of substantially uniform depth, - plurality of spike rolls rotating about substantially hor-izontal parallel axes spaced vertically apart and located at one side of the pile of wood strands, the spike rolls adapted to pull wood strands out of the pile, and form a uniform curtain of falling strands, - advancing means for the pile of wood strands to force the pile, against the spike rolls, - a pair of counter-rotating spreader rolls side by side in the same horizontal plane, the spreader rolls having axes substantially parallel to the spike roll axes and located beneath the spike rolls to receive the curtain of falling strands, - each of the spreader rolls having a plurality of radially extending spikes to distribute the strands evenly in a mat beneath, - means to rotate the spreader rolls in counter-rotating directions such that strands distributed by the spikes are directed outside the spreader rolls and not in between and, - horizontal adjustment means for the spreader rolls to adjust the location of the spreader rolls beneath the curtain of falling strands, and provide a predetermined distance between tips of the spikes on one spreader roll and tips of the spikes on the other spreader roll, and ensure that the tips of the spikes on one spreader roll do not overlap with the tips of the spikes on the other spreader roll.
2. The apparatus according to claim 1 wherein the means for forming the pile of wood strands includes a rake back conveyor located at the top of the pile, to convey wood strands at the top of the pile away from the spike rolls and wherein the advancing means includes a conveyor at the bottom of the pile to advance the pile towards the spike rolls.
3. The apparatus according to claim 2 wherein the plur-ality of spike rolls are located between the rake back conveyor at the top of the pile of wood strands and the conveyor at the bottom of the pile, the axes of the spike rolls are in a substantially straight line sloping upwards towards the rake back conveyor.
4. The apparatus according to claim 3 wherein the straight line slopes upwards at an angle in the range of about 55 to 60 degrees to the horizontal.
5. The apparatus according to any of claims 1, 2 or 3 including an orienting means located beneath the spreader rolls and above the mat, to provide an orientation of strands in the mat.
6. The apparatus according to claim 1 wherein the spike rolls adjacent to each other have spikes which inter-mesh and overlap.
7. The apparatus according to claim 1 wherein the spike rolls adjacent to each other have spikes in line, and a space is provided between the tips of the spikes on one spike roll and tips of the spikes on the adjacent spike roll.
8. The apparatus according to claim 1 wherein the rotational speed of the counter-rotating spreader rolls may be varied.
9. The apparatus according to claim 1 wherein the spikes on the spike rolls and on the separating rolls are formed from flat strips, each of the spikes having a rectangular cross-section with a flat face attached to angle sections, extending axially along the face of the roll.
10. The apparatus according to claim 1 wherein the rotat-ional speed of the spike rolls may be varied.
11. The apparatus according to claim 2 wherein the speed of the conveyor at the bottom of the pile may be varied.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000412025A CA1176423A (en) | 1982-09-23 | 1982-09-23 | Apparatus for laying a mat of wood strands |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000412025A CA1176423A (en) | 1982-09-23 | 1982-09-23 | Apparatus for laying a mat of wood strands |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1176423A true CA1176423A (en) | 1984-10-23 |
Family
ID=4123646
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000412025A Expired CA1176423A (en) | 1982-09-23 | 1982-09-23 | Apparatus for laying a mat of wood strands |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1176423A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102015118881A1 (en) * | 2015-11-04 | 2017-05-04 | Dieffenbacher GmbH Maschinen- und Anlagenbau | Discharge roller for discharging material, device with a Austragungswalze and a manufacturing system for the provision of material in the course of the production of material plates |
| WO2017207449A1 (en) * | 2016-05-31 | 2017-12-07 | Dieffenbacher GmbH Maschinen- und Anlagenbau | Distributing apparatus and method for supplying particulate material continuously to a forming belt |
| CN111918754A (en) * | 2018-03-28 | 2020-11-10 | 辛北尔康普机器及成套设备有限责任公司 | Dispensing device |
-
1982
- 1982-09-23 CA CA000412025A patent/CA1176423A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102015118881A1 (en) * | 2015-11-04 | 2017-05-04 | Dieffenbacher GmbH Maschinen- und Anlagenbau | Discharge roller for discharging material, device with a Austragungswalze and a manufacturing system for the provision of material in the course of the production of material plates |
| DE102015118881B4 (en) * | 2015-11-04 | 2017-07-13 | Dieffenbacher GmbH Maschinen- und Anlagenbau | Discharge roller for discharging material, device with a Austragungswalze and a manufacturing system for the provision of material in the course of the production of material plates |
| WO2017207449A1 (en) * | 2016-05-31 | 2017-12-07 | Dieffenbacher GmbH Maschinen- und Anlagenbau | Distributing apparatus and method for supplying particulate material continuously to a forming belt |
| CN111918754A (en) * | 2018-03-28 | 2020-11-10 | 辛北尔康普机器及成套设备有限责任公司 | Dispensing device |
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