Document evLRp2XkMw0w6rB75q4vY8jM4

Lwr Latest developments in paper machine dryer fabrics Widely known expert on paper drying discusses dryer felts, open-mesh fabrics and pocket ventilation. E. Race, Research Director, Scapa Dryers, Ltd Although fabrics of very high perusability receive most publicity now* adays. and although the time may come when such fabrics become stand* art! clothing, it is worth remembering that well over 80 per cent of ail dry* ing sections throughout the world are still clothed with conventional dryer felts of low permeability Therefore, the dryei felt manufacturer must con tinue to develop and improve convert* tional felts as well a>i open-mesh fab rics. Not only Is there a trend towards the use of higher dryer surface tem peratures, but also, as more machines arc totally enclosed, there is a tend ency for conditions of higher humid ity in the dryer part. Jf, because of hooding a machine or for arty other reason, the temperature of a dryer felt in service is Increased 18kF and its moisture content Is increased only erne per cent, the rate of degradation of the cotton of the felt will be in creased five-fold. When a dramatic reduction in dryer felt life occurs and the machine at mospheric conditions causing it can not be corrected, then a dryer felt of different composition is required, Scapa Dryers, Lid., has recently mar keted a series of felts, made from a non-hydrolysable synthetic fiber, for use cm positions of high humidity. Dryer surface temperatures of 360SF, art now being employed. It cannot be expected that dryer felts made predomioantly of cotton, or even of the usual type of synthetic fiber, wifi last for Jong at such blgh temperatures. One fiber that will with stand such severe conditions of serv ice is the new Du Pont Nome* nylon. Is addition to high, strength, tough ness, abrasion-resistance and hydroly sis-resistance, Nomex ha* outstanding resistance to very high temperature*, Scapa has supplied dryer felts made partly of Nomex and partly of high quality asbestos for operation on the roost destructive dryer positions io the world. They ace running satisfactorily, and some of (Iscm have already proved themselves economically worthwhile, even though tlie initial cost is high. Other felt Improvement* An exaaiaalioci of thousands <>t used predominantly cotton dryer fcTts reveals about one-third of them have been degraded by traces of acid ac cumulating in the felts during service. Scapa has developed an anti-acid treatment which it proving successful m protecting the felt against the de structive effect oS this acid There is some evidence, too, that the* same treatment gives n measure of pioicc- iinn to cotton against heat Scapa's twin roller clipper seam is now becoming welt known ft has been developed tci overcome the abra sive effect of the metal clips on the hmge cable when the dipper seam bends round the felt rolls. In the twin roller seam, the dtps are of a special si/e and shape to take two hinge cables which lie side-by-aide. "05056 two cables are kept in rolling contact, and each set of clips is stationary with respeer to one hinge wire The Scapa twin roller seam is capable of outlast ing the lives of the longest-running dryer felts and fabrics. Eighteen years ago, Scapa Dryers initoduccd cotton dryer felts wish syutlietic edges to protect against oil damage. They have now developed a treatment, applicable to (be edges of alt types of dryer felts, which confers oil resistance to the edges. According to tests carried out in a Finnish paper milt, this same treat ment applied to ao entire Scapcrtn open-mesh fabric keeps the fabric much cleaner titan an untreated fab ric when they are run on aa aftercoating position. Open mesh fabrics Open mesh dryer fabrics, are now well-established. Scapa Dryers has supplied more than 1,800 of them from iu Blackburn plain aioBc, and they are running on machines making all types of paper from condenser tissue to newsprint and sack kraft. The expected advantages obtainable from the use of open-mesh fabrics arc: an economic service life; an in crease In machine speed; a decrease is steam consumption; and an im proved cross-machine moisture pro file. There are * few cases in which all of these advantages are claimed, yet more in which two advantages arc ob tained But ihere are numerous in stances in which open-mesh fsbncs are being run solely because of the ex tremely long life obtainable from them. U is becoimng not uncommon io hear of Scaperm fabrics running on machines for 4(X> or 500 day* and even longer. Why it is that on some machines open-mesh fabrics give the advantages for which they were designed, and on others the sole advantage (albeit an important one) is a tuw cost per ton of paper? In some cases it may be merely that the clothing of one ot (wo posi tions out of a total of four, six .or eight dryer positions on the machine is not sufficient to have a quantita tively noticeable effect. But if all o? most of the positions being clothed with fabrics do not produce a poten tial increase in machine speed ot a better moisture profile, then we mjtst ask why. Rocket ventilotieA j ii Prom the many paper-machine s ir- vcys carried out by Scapa enginei n, it would appear that the atraospbi ric conditions in and around the pa *er machine are often not"conducive to the production of the highest efflei ;n* cy from the open-mesh fabrics. Op in mesh fabrics such as Scapenijof themselves pump air into and jt jd of (he dryer pockets, and if the,[a (Cen tering the pocket has a fewer's&d&tc humidity than"that in' th log of the shitif I a* - sbisoteudd.:^Syj.mlailytLerrtyaic'i&f,i*orit * ' **' ric M'i^confto cylinder ui''1' * ` ing rfttiW with & .fell, not pi$, ' be ga(fi|d by ric ttil.&>t"t ?<sl m a!Jmm rsfo*- Actually, ventilation system, fasftircti by Seapa which presents dry,:wanij!;aij fabric passing from cylinder roll will ensure that the 'fir. into the pocket will lower tfj$' ity in the pocket and iscrea evaporation rate. The sheet Sutter that has oc when open-racsb fabrics are usfcd ap pears to be confined mainly to first sections of machines making p^pi r of newsprint or lighter weight at speeds in excess of 1,500 f.p.m, wbbnj the fabrics .on the first sections haVe a Paper Trade Joumel/November 20, 1967 PLAINTIFFS milMEXHIBIT permeability in excess of 285 c.f.tn./ sq.ft, at one-haif inch water gauge. Measurcrosots have shown that the air turbulence which causes the sheet flutter is a function of the permeabil ity of the fabric sod not of the surface roughness of the fabric. In order to combat sheet flutter, Seapa males a range of Seaperm fabrics of permea bilities ranging from more than 700 ci.na. to leas than 150 c.f.nv Again, measurements have shows that the air carrying capacities of felts or fab rics of permeabilities less than 150 c,,m, are all equal. Hence, there is nothing to be gained in the produc tion of fabrics of permeability fes9 than ISO c.f.m. Why did Seapa choose to male their open-raesh Scapcrms of multifilameat yarns, resin-treated? Initially, Scopa made both monofilament and multifilamem fabrics. Better results and greater versatility were obtained from the multifllameot fabrics. Oue important reason why multifila ments were chosen is the range of raw materials which can he used. A good illustration is the recent production of a Scapemi made wholly of Nome* multifilamcot yams, treated with a resin capable of witbstoading the most severe paper machine dryer section condition?. Adjustable speed drives eaUbg A new eigbtittge catalog covering the complete line of Ajuito-Spcdc cddy-carrem, air cooled adjustable speed drives and control systemic-products of the Dynsmatic division, Eaton Yale and Towce, Inc., is now available. Afosco* Spede drives are available in three dif ferent configurations based on horse power and speed capacities: models ACM-902-9GS (V* through 15 ftp}, models ACM-W6-9U 0 through 100 hpj. models ACM-9155-9166 <75 through 3t)G hp), Each size is presented separately in the new literature with detailed dimensions and application dma Com pleting the cutalog are cutaway iUostra. lions of die drives, application series plus details on Dynamic controllers, in. eluding (lie microelectronic controller? for Models ACM-902 through 905. Copies of the new catalog are available in response to company letterhead re quests only. Write to Eaton Yale and Townc. Inc., 100 Fiieview Plaza, Cleve land, Ohio 4U4. NEW tnflico presauru After* A new* bulletin from Fuller 6., a subsidiary of General American Tiaas- LITERATURE rortatioR Carp,, describes the company's riftlco pressure filters for water HUrjaiioo in industry, municipalities, and iaktitti- lion*. The four-page bulEelin contains information on toe factors that necessi tate the filtering of water endl the numerous abdications for the pressure filters. Other sections of the bu&etio spraying trolled by the plasma flame spray Bystem, Bulletin 142F also covers the fabrica tion of parts by spraying u refractory material on a mandrel, and lists several kinds of parts successfully produced by this technique. Copies of the btiUsria "The Metro Plasma Flame Spray Process,* ore available from Metro, ta,, describe the construction aod operation of the filters, including detailed informaik>o on backwash procedures. Informa tion Is also given on the various)tank sizes, underdraJos, and Alter medial that are available. For a copy of (uhtia N-tGO, write Falser Co., P. O. j gox 5033, Tucson, Aria. 1101 Prospect Avenue, Westbury, N. Y. 11590. Chemicals 'Hu latest &ttlqaj of Mbui- Eaton hydraulic deaurger A bulletin has been pBbiished,on Uie recently oWroduced Eaton Hj&riWk leiin, "Chemicals qrtbe Rupee is now svafta&e fro'ra i'ii Co., FWIaddj ~ desurger, a product of the Glfev&laxid Wow and Gear drriskm of ain Yale and Towns, ftie. The desurger'^fSjdeslgned to reduce pohaticflt, .v$tijjjibn, ;de6|Hi noise, and hydraulic shock Ao fltu&sys- tesss, Tt&l dpsoiger buQ^Qs, describe? frdjal&teO'.' )/ available describes plasma Same 3 ' how tic process api&crease wear rewa- Ifccfc'Sop prov oxidation and cheotical thermal barriers, and Insulate of conduct electricity, Pja5ni& flute sprayed coatings are sow behlgspplied in original manufacture of oyer 500 critical jereadne pans. A chart in the new buileufe 142F, shows eleven Metro coathigs cunsnUy fasiag used and describes tbeir fttnflrioaa. Another chart outlines 25 iypig|ljjatfs on which plasma owns sprayed coatings are being applied, in why and how of dogma flame coat ings. the means by which they're applied, and tfnar further potential applications a disewsed in the oew Metro bulletin. The basic process itself is tersely and dearly outlined. A section describes how coating' properties are precise!? con construction.&ntT operation <& product performance repetitive wtlh'Jeharla* desorger m redScTbfe f; MU pnlsafioos. A seflSi Of 'included U> aidfrin&, determining pro w demerger siae for *%? variety of uwWloos, Balletic D-lOGrf ! roadod?* .pfifline drawings and do v of all types of de- < surgera/witt jo'R. N. BUiiftlleKr, Clevc- land Worm and Gear division, 3249 Ease #(hb Street, Cleveland, Ohio 44104: ' '< * Belbit'Jpni The IotM; Switchboard iBsbimwntstlon . offers a ti tin, SB-35. General Electric tua a new 36-page bulletin describing Its juec&ozt-bult line Jones Vertifleji^ signed for rize re? of switchboard instrumentation. Included in (he bulletin are price tables, descrip dry or slurry fed gravity fed to simpl tions of optional features, ratings and calibrations, construetwo features, dimen ment. There is haodwj clearance between dii sions, specificajkroB, a section cm opera- fnm 50D to 1000 bp, uob and special designs, technical bfon&ation including wiring diagrams, and a variety of footh aad bar lures are described, together general application information, This bulletin is GEC-15078. For free copies write: General Electric Co. Distribution ServiMa, Btaidioo 6-205, I River Bead, Schenectady, N. r. 12305. Biona nod a cutaway drawing] internal cota(ruction. Cojtiae a able from: Beloit Corn. Jones SJuct information droartcni 1, Mass. 012W. m Ui S1 11(Hi, [Fitts- Paper Trade Joumel/Novefeber 2^, 1967