Document n9jBe5dZG1R44xMOyYL31VvZw

FILE NAME: Sprayed Asbestos (SPRA) DATE: 1952 July 22 DOC#: SPRA010 DOCUMENT DESCRIPTION: US Patent - Process for Damping Mineral Fibers to be Sprayed in Air / / > j; | i J . Patented July 22, 1952 I 2,604,416 UNITED STATES PATENT OFFICE ' ) 2,604,41G PROCESS F O R DAMI'INC, MINERAL FIB ER S TO BE SPRAYED IN AIK, Norm an L. Dolbcy, Anility, Leeds, England, a s signor to J. \Y. Roberts Limited, Aririley, Leeds, England, a British company Application September 30, 1947, Serial No. 77G.9C4 / . 4 Claims. (CL 117-- 100) ! 1 2 A very effective way of forming insulating agent while -t is travelling in a thin layer and con tings on walls, ceilings or oth e r surfaces is before it is suspended in air. I control the darao- to spray asbestos fibre v/ith or without other m a- ing in accordance with the'flow of fibre and in teiial and with an adhesive or ingredients which feeding the damped fibre particles into'the air I react to form an adhesive. 5 cu n e n t I pievent suction being exerted to any Tins process can advantageously be <-.irried out substantial ex ten t on such dust as is formed so in the manner and with the apparatus described th at practically no such dust is drawn into the in United S tates P a te n ts Nos. 1,990,584 an d air c u rre n t 1,990,585 issued to me on February 12, 1935, the I t is im portant th a t the damping should be as fibre being suspended in air and th e n subjected 10 uniform as possible an d for this reason th e fibre to suction but when this is done there is one should be spread out into a th in layer, th a t is to practical drawback. Tins drawback is th a t dust say, one th.nner th a n is usual a t the present escapes into the atmosphere during the spray time. Tne damping agent sprayed on to this ing operation and, in order to overcome it, many layer may be w ater in atomised form, oil or any expedients have been tried. The drawback can IS appropriate liquid. I t is simplest to use water, be overcome by the method described in my and the water je t should be as fine as possible. United States application Serial No. 603,616, I n addition to dam ping the th in layer of fibre, July 7, 1945, p a te n t No. 2 533,457 issued August f..eh a j e t a No creates %. fog-like atmosphere 7, 1951, th a t is to say, by mixing th e asbestos wnich tends to cause any dust form ed to settle with a predetermined quanrity of w ater or other 20 v.itliin th e apparatus. damping material In such a way that in the I prefer to effect the damping in a casing, course of the mixing substantially every particle through which the thin layer travels and which of asoestos is damped and the dam ping m a is substantially closed, and it is an important terial is so uniformly distributed th roughout the feature th a t the interior of this casing ;; not in asbestos th a t there is no tendency for particles 25 com munication w ith a n y space under low p res to stick together by reason of different moisture contents. In m y said application No. 003,61c I sure such that dust in suspension in the casing would he drawn out of it by suction. have also described apparatus by which tms process can be carried out, this apparatus in - ; corporating a ro ta ry mixing drum ad a p te d to 30 carry the asbestos upwards as the drum lotah's and a rotary brush mounted within the drum to In carrying out the process I prefer to employ an apparatus such as that shown ill my Patents 1,990,584 a n d 1,990,585 w .th a conveyor belt to carry the fibre upwards past a brush which ie -ves to remove all the fibre except the desired engage the asbestos which is carried upwards tn .n layer and to modify this apparatus by pro and by a beating action to open up fibre bundles viding means for spraying atomised water onto end. ihng the particles through the drum to fall '-1 e th in layer while it is still on the conveyor to the bottom and be carried upwards again. bi t, U e layer being removed from the belt by Such a n apparatus serves_to tre a t batches cf a -tripping brush. T he thinner the layer of asbestos fibre. Now it is desirable to be able to flbia which is sprayed with the water th e'better work continuously, th a t is to say. to ieed dry the results, as the fibre and water become more asbestos to an a^ poratus sucli as th a t m o w n in 4D uniformly mixed. I t is possible to make the layer my P atents Nos. 1,990,584 and 1,990,585 a n d to th in n e r w ithout reducing the capacity of a given spray it without having to damp the fibre in apparatus by increasing the speed of the con / batches. An object of this Invention is to enable veyor and making the first brush approach the ! asbestos or other m ineral fibre, e. g. glass fibre, conveyor closely. I find it impossible to dam p \ to be supplied in a cu rren t of air to a spraying 45 die fibre absolute!} uniformly while it is on the i \ device substantially free of dry and loose dust. ' conveyor and accor-Iingly a little dust is produced Another object of the invention is to provide by the action of t i e stripping brash and con improved means for damping' asbestos or other veyed to th e spray r device. However, this dizrt fibres. As a result of m any researches, I have is r latively small :r am ount .aid to keep it t c f o u r i t h a t the dust c a n be reduced to such a n 60 a m inim um the sp< ed of th e stripping brusfa- extent t h a t th e drawback of dust escaping into shojJd be made as 1( w as possible. the atmosphere is largely overcome, although the In th e apparatus described in ray P ate n ts Nosl t forms,tion and spraying of c u r t m a y n o t be com 1,990,504 an d 1,990,585 the a ir Into which the pletely eliminated. In the present invention I particles are projected is drawn into the uctlon- spray- th e fibre w ith water or o th e r dam ping B8 inlet of a fan, so in effect tr.e particles form a- ( 2,604,410 suspension In a moving current of air and this drum forms the upper roller for an endless belt suspension is conveyed forward by the fan. I n conveyor II, which also passes over a roller 12 t h a t a p p a ra tu s it is the f a n which produces th e carried in bearings 13 supported by the members neatest p a r t of th e dust. I n th e present inven G an d 6'. T he conveyor ( I is driven fcy an elec- tion I may still use a f a n but by the tim e the 6 trie motor IG m ounted on the base members I. fibre arrives a t the fan it Is already sufficiently the m otor being connected by a driving belt 16 damped to prevent any appreciable form ation of to drive a wheel 17 keyed to a sh a ft 18 which further dust in the fan. passes through the drum 10. This s h a ft IS is So f a r as possible, no dust should be draw n carried in bearing brushes within sleeves 19 and forward with the fibre and, to this end, I prefer 10 19'. which en ter the drum (as shown in Figure to modify th e apparatus further. In the first 4) and which are themselves Jourr.alled in the place, when I employ a f a n to convey the sus bearing plates 9. T he sleeve 19 is secured to a pension forwards, I prefer to cause th e f a n to transverse a n n u la r plate 20 which is fixed inside draw hr air from th e atm osphere so th a t the the drum. T he sleeve 19' is secured to the casing suction which it produces is not exerted to any 18 of a gear 21 of the cpicyclic type, 'which is itself substantial extent upon th e interior of the casing. secured to an o th er an n u lar plate 22 fixed inside This result is preferably a tta in e d by splitting the drum. T he gear 21 connects the s h a ft 18 into two p a r ts a duct th ro u g h which th e fibre an d a sh a ft 23 to which a wheel 24 is keyed. falls from th e stripping brush, th e upper e r d of This wheel h as a series of holes 25 around its the lower p a r t surrounding an d overlapping th e 20 periphery and these can be engaged by a plunger lower end of the upper p a r t so as to leave a space 28 m ounted to slide in a cylinder 2f fixed to the through which air can be drawn in from the side of the apparatus. When the plunger enters surrounding dust-free atmosphere. one of toe holes 25 the s h a f t 23 cannot rotate: Instead of causing the particles to pass in these circumstances the sh a ft 18 drives the through a f a n I m ay entra in th e m In a n air c u r 25 drum 10 through the gear 21. If, however, the re n t which m ay itself be produced by a fan. For win el 24 is free to rotate as a result of the with- Instance, the particles on being projected Into air diawal of the plunger 25 from the hole 25, the by a stripping brush may fall down a funnel-like frictional resistance of toe drum 10 and con duel to a continuously r o ta tin g valve of the s ta r veyor 11 causes the gear to drive the s h a ft 23 or gate type, through w hich the particles pass 30 preferentially an d the drum and conveyor stop. into a pipe in which the air current is flowing. Above toe conveyor II there is a sheet m etal Such a valve serves to break any suction which hopper 28 which is kept charged with asbestos would otherwise be applied to the interior of the fibres and has a lid 31 hinged a t 32 to a fixed casing. cross-piece 38. B eneath the lower ru n of the As stated above, the spraying of the dam ping 35 conveyor there is a sheet metal plate 33 which agent m ust be controlled in synchronism with spans the two side members 3. the movement of the fibre. In existing appa Tiie central p art of the conveyor II carries a ratu s for spraying asbestos fibre, it is usual to series of spikes 34 a n d jan each side of these the provide a pneumatically operated clutch for the belt is smooth a n d projects laterally beyond the conveyor belt and to operate this by a device 40 hopper 28, so t h a t in effect the bottom of toe fixed to the spraying nozzle so th a t the belt is hopper is formed by the spiked p art of the con stopped whenever spraying is stopped. In the veyor. When the conveyor is running the spikes present invention the spray of atomised water, 34 pick up asbestos and carry it upwards. I t is oil or other damping agent may be stopped simul . im portant th a t only a thin uniform layer of as- taneously under the same control. 45 bestos should rem a in on the conveyor a t toe top T he preferred form of a p p a r a tu s according to of the upward run, and a brusn 35 is provided the invention will now be described by way of to sweep over the conveyor und detach and r e example with reference to the uccotnpan.ung turn to toe hopper any asbestos in excess of this drawings in which: thin layer. This brush is carried in bearings Figure 1 Is a som ew hat diagram m atic eleva 50 which are fixed to the fram e members 2, the tion of toe apparatus, partly in section; shaft of the brush passing through bushings In Figure 2 is a section cn toe line II--n in Fig the side walls of the hopper. ure 1; T he thin uniform layer of asbestos which is Figure 3 Is a central vertical section through left on tiie conveyor by the brush 35 passes be- th e p a r t of th e a p p a ratu s shown In the upper 55 n e a th a plate 43 winch spans the interior of the r ig h t- h a n d p a r t of Figure 1; hopper 28 a n d forms one wall of a dam ping Figure 4 is an enlarged section on the line chamber 4t, tiie bottom of which is formed by IV--IV in Figure 3; an d the conveyor t l . The sides of this chamber are Figure 5 is a perspective view of p a r t of th e constituted by walls 53 which are offset from interior of toe apparatus; and 60 the walls of the hopper 28 an d Joined to them by Figure G is a diagram m atic view of the m e c h a curved walls 58. T he chamber 41 Is th u s wider nism for controlling the damping. th a n the hepper 23 and In fact it Is nearly tiie T he a p p a ra tu s is carried by a n angle-iron full w idth of the belt II. / long toe walls 53 the framework having two side frame- each com side members 2 arc made narrower as shown in posed of a base member I, inclined side members 65 Figure 4, and the walls of the hopper 28 an d 53 2 a n d 3, a vertical m em ber 4, a top m em ber 5, are united by cross parts 64 which stop s h o rt of two members G an d G' s p a n n in g the members 2 toe smooth edge surfaces of the conveyor II. find 3 an d a n inclined m em ber 7 uniting the T he result Is to form openings 59 a t <i ch side of members 5, 3 and 4. T h e two side fram es are to e cham ber 41, these openings leading onto the united by cross-members (not shov.m) a t the 70 members 2 outside the hopper 28. The top of th e base an d top. Tile space a t eacli side between cham ber 41 is constituted by a lid hmged a t 43 the members 2, 3. 5 cmd 7 is closed bv cheek to toe cross-piece 38. plates 8 and 9, the plate 8 a t each side being of I n the damping cham ber 41 there is a spray sheet metal an d the plate 9 being t. casting which nozzle 44 held between semi-circular p arts 45 of serves as a m a in bearing for a dru m 10. Tire 75 two straps 45 which are welded together a n d to ,2 60^,413 \cJr th e side wills of th e chamber 41. This nozzle quent fan-like effect it produces. T he purpose j 44 Is fed with w ate r through a pipe 47 and with of the invention is to reduce to a minimum the ; compress:d air th ro u c h a pipe 48. I t Includes a n orifice 49 which can be dosed by a needle valve amount of d'lst delivered to the spraying d e v ic e ! 85, and the ap p a ratu s shown in Figure 1 can If! 50. W hen air is a c i n i ted through the pipe 43 it acts on the underside of a diaphragm 51 which is secured to the stem of the needle valve 50 and so moves the valve away from the crillce 49. At the same time the air passes throuch a narrow 5 necessary be put where dust escaping from It l&( not deleterious. Ifowevei any dust produced In) tiie hopper, 25 will In the m ain stay In the h opjxir. Dust directly produced by the brush 37 Is for the most part directed into Ihe hopper. Dust an n u la r passage 52 to the orifice and atomises n> in the damping cham ber 4) will either stay in water flowing to the orifice fiom the pipe 47. The nozzle then delivers an atomised fan-shaped spray of water which when it strikes J.e con veyor is of the sam e width as the p a rt covered suspension or become damped by the moisture in the atmosphere. So long as it. Is in fuisuenslaq in the chamber it is harm less. Once it has becciffeTruii'p enough to'fall out of the suspension by the spikes 34. T he am ount of water may, for 15 it is no longer h a rm fu l oust b u t la th e r dam p example, be fiom 5 to 10`;i by weight of tile as bestos. The spray damps the asbestos substan tially uniform ly tend produces a moist atmosphere ir. the damping chamber 41. particles of asbestos which can be allowed to fall to the ground to be swept up later if they pass out through the openings 52 or 75. T he layer of asbestos Is not lifted fiorn the conveyor unti As the convey or begins its downward run the 20 it has been damped, so only little dust i; pro asbestos is removed by a shipping brush 0 which duced by the stripping brush 60. the part of is m ounted on a s h a ft 61 carried in bearing the cham ber 70 below the brush 60 is not under brackets 62 which are fixed to the fram e m em - low piessure, there is no tendency for dust to bers 7. This s h a ft Gl is driven by a belt 64 from be d : a r n in and p a s t the brush 60 from any p a rt the sh a ft 18 and m tu r n it drives the sh a ft of the 25 of the interior of th e casing by suction. Instead \ brush 35 through a belt 65. the brush merely detaches damp fibie fre n the I T he brush 60 works in, and in cUect constitutes conveyor a n d conveys onwards dam p particles \ a wall of, a cha m be r 70 having side walls 71 which are already falling in the upper p a rt of the \ aligned with the side walls of the hopper 28 and c h a m b 'r 70 an d which, because they art. falling, f secured to the members 7 This cham ber 70 Is SO are n e t h arm fu l dust. ~ --------> closed by a curved lid 72 L . ;ed a t 73 and it Is narrow er th a n the cham ber 41. W here the two chambers meet th e re is a cross-plate 74 which stops short of the smooth edges of the conveyor The compressed a ir supplied to the nozzle 44 is small iii volume. I t is supplied under a pressure of, say 30 lbs. per square ir.cli an d it sets up very little pressure in tire damping cham ber 41. E .e n an d eaves openings 75 through which any m a - 35 this pressure is largely relieved beneath the lower terial cn the smooth edges can pass. T h e chamber 70 m tu ; n merges into the top ol a chute 76 into which the particles of asbestos detached by the brush 50 fall. This chute has edge of the plate <7, and the turbulence In the damping chamber is actually advantageous in maintaining dust in suspension until it is damp enough to fall down onto the conveyer. side walls 77 which overlap tne lower p a r t of the brush GO, a wall 78 which neaily touches the spikes 34 on the conveyor II and a wall 79 which extends far enough upwards to lorm an abut m e n t for the lower edge of the lid 72. 40 T he provision of th e smor.tr; cJgcs of the con veyor belt II allows the wetting spray to cover the fibre adequately, w.thout imping.ng directly on the side plates 53. I n time the rid: plates 63 become dam p and when ,. certain deci ee of dam p- Hie chute 76 k; continued as tlie first half 80 15 r.ess Is r e a d ie d there Is t tendency for small p e r of a t'w o-part d' uct', t"he iccond' p a rt of- whic-h, tions of air-borne fibre to cling to the dam p s u r 81, has a n outlet registering with the suction inlet of a fan 82 m ounted to rotate about a h o ri zontal axis. This fan is driven through a belt faces and build up as clots. W hen these small clots become overwetted they fall onto the smooth edges ol' th e belt II en d roll back down 83 bythe motor J 15. I i receives the particles of 50 these smooth edges and out through th e open ' ins w.h..i.c..h.....f..a..l.l....d. own t..h..e....d...u..c..t....a..n...d....d...e.l.ivers hips 59. them through a pipe 84 to a spraying device 8'. Thus it will be se .n th a t the Interior of the ] From this device the asbestos is sprayed at the casing is s u b s t a n tia ', j closed and n o t subjerred io j .'..ime time ns an emulsion of rubber in water suction, so t h a t very lithe dust escapes fiom it 1 which r. supplied to the orvlce through a pipe 55 and the fibre corweyed to the spraying device is j EC, the r>,;>e tos and emi Ision being projected si bstanllally dust-fiee. ' onto a will or other surface la be coated. The The operator controls the whole operation emulsion Is sprayed and atomised under the ac through a ; ingle operating handle 35 v l.'c h is tion of eompres'i d air d - 'tvejvd ihrough a pipe connected to r. double valve which controls the El and I', acts an adhesive for the asbestos. fi0 i.ow in both The pipes 86 an d 87. A pipe 96 I t i 1.1 be ob e rved th a t the lower end of Ibe blanches lrom the pipe 86 and runs to the cylin P -t 11` of the d i d lies wholly within th e mouth der 27. Tills contains a piston S8 which is of in" pint ill. which is itself surrounded by a moved against i spring 89 w hen a ir is allowed to lea si '0 .so as !o leave an annular o p.nlng 81 flow in tire pipe 96 an d which carries the plung i h n . ; U which the air can be drawn in. Jiv G5 er J 8. As a ic.su l, whenever th e handle 95 is ip ho: imh a kronen duct the mu for, ex ;rted by turn ed to stop the spraying of th e asbestos the tl r ! a app', rd .Minshmilaliy entirely to the s a.:* *'' i*.j>' `h the openlnp 61. plunger 16 i; w ithdraw n, th e wheel 24 tu rn s and tiro belt is stopped. It v . 1 i,a sin a th a t in the appaintus shown the M'1 1. . tiuvD. ; ' h i o i r l i a substantially closed 70 T he pi,x. 18 i o.is from th e cylinder 27 to the ( . Ii:,;' *dl!' h 1. (In iked into (or constituted by) nozzle 'If, and v h e n e v e r th e conveyor is stopped the h . 'I .IV ! the rli.c.ib'Ti 41 and 70. I t Is the supply of air tc the nozzle 44 is else, stopped. III!". 11 .' ' Ul.'.t r v (iii; t will be foir.ied within T he water Epray Is Dien stopped because the 1- tb's i \ Ivy, If v y bee,.use of the high spefd at sphrugm 51 moves th e needle valve 50 to close ,v` h b il c b l".'h 95 must rotate rind the eons':- 75 th e orifice 19. ..',6 0 4 ,4 1 0 t I claim: 1. I n a process for delivering' loose mineral 8 fibers from each o th e r as they are received into said air space and simultaneously scattering and fibers to a spraying device having a high velocity projecting said separated fibers In the ucoer part air stream, the steps of arranging the mineral of said air space, establishing a current of air fibers Into a relatively tnin, flat layer on a mov 5 flowing downwardly from said intermediate air able su pposing surface, advancing said layer inlet to the open lower end of said air space by continuously by moving the surluce, dampening creating a partial vacuum at said lower end, said fibers with an atomized liquid as the layer whereby as said separated fibers fall through the advances, substantially separating the dampened upper p art of said air space and into the flowing fibers from each other as the layer advances and 10 c u rre n t of air In the lower p a rt of said air space simultaneously scattering said separated floors th e fibers are forcibly delivered by said current into the upper part of an enclosed air spate of air Into the high velocity air stream of the which Is opened a t Its lower end and which has spraying device. Intermediate its upper and lower ends a restrict 4. A process as s:t forth in claim 3 and which ed opening to the atmosphere, establishing a 15 includes the step of m aintaining said partial downwardly flowing current of air in the lower vacuum at the lower end of sa. i air space of such p a r t of said air space by creating a p artial low intensity t h a t substantially no air or dust Is vacuum at the lower end thereof, whereby as said drawn from th a t p art of the enclosed air space separated fibers fall through the upper c a r t of which Is above said intermedite air inlet. said air space an d into the flowing c u rre n t of air 20 NORMAN L. DOU1EY. in the lower p a rt of the air space they are for cibly delivered by said current of air into the high REFERENCES CITED velocity air stream of the spraying device. The following references are of record In the 2. A process as set forth in claim 1 and in which file of this paten t: the mineral fibers are asbestos. 3. In a process for delivering loose m ineral 23 UNITED STATES PATENTS fibers to a spraying device having a high velocity Number Name Date air stream, the steps of arranging the mineral 1,072,530 N o v a k _______________ June 5, 1923 fibers Into a relatively thin, flat layer on a mov 1,718,507 Wenzel et a l . _______ Ju n e 25, 1929 able supporting surface which leads into th e top 30 1,870,094 C a r l i n _______________ Aug. 2, 1932 of a n enclosed air space which is open a t its 1,990,584 D o l b e y ______________Feb. 12, 1935 lowei rn d and has a restricted air inlet in te r m e 2.438,471 Bail _______________ Mar. 23, 1948 diate its upper and lower ends, advancing said layer progressively into said air space by moving said surface, dampening said fibers while on said 35 N um ber surface with an atomized liquid as said suiface 388,924 FOREIGN PATENTS Countly Date G r e a t B r i t a i n ________ Mar. 9, 1933 advances, substantially separating the dampened