an autobiography-第99章

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eting　of　the　British　Association　at　Ipswich　in　1851。　　These　were　afterwards　published　in　the　Mining　Journal。　　The　consequence　is　that　many　of　my　Suction　Ventilating　Fans　are　now　in　successful　action　at　home　and　abroad。


1845。　An　improvement　in　the　Links　of　Chain　Cables。



1845。　An　Improved　Method　of　Welding　Iron。

One　of　the　most　important　processes　in　connection　with　the　production　of　the　details　of　machinery；　and　other　purposes　in　which　malleable　iron　is　employed；　is　that　termed　welding；　namely；　when　more　or　less　complex　forms　are；　so　to　speak；　〃built　up〃　by　the　union　of　suitable　portions　of　malleable　iron　united　and　incorporated　with　each　other　in　the　process　of　welding。　　This　consists　in　heating　the　parts　which　we　desire　to　unite　to　a　white　heat　in　a　smith's　forge　fire；　or　in　an　air　furnace；　by　means　of　which　that　peculiar　adhesive　〃wax…like〃　capability；　of　sticking　together　is　induced；so　that　when　the　several　parts　are　forcibly　pressed　into　close　contact　by　blows　of　a　hammer；　their　union　is　rendered　perfect。

But　as　the　intense　degree　of　heat　which　is　requisite　to　induce　this　adhesive　quality　is　accompanied　by　the　production　of　a　molten　oxide　of　iron　that　clings　tenaciously　to　the　white…hot　surfaces　of　the　iron；　the　union　will　not　be　complete　unless　every　particle　of　the　adhesing　molten　scoriae　is　thoroughly　discharged　and　driven　out　from　between　the　surfaces　we　desire　to　unite　by　welding。　　If　by　any　want　of　due　care　on　the　part　of　the　smith；　the　surfaces　be　concave　or　have　hollows　in　them；　the　scoriae　will　be　sure　to　lurk　in　the　recesses；　and　result　in　a　defective　welding　of　a　most　treacherous　nature。　　Though　the　exterior　may　display　no　evidence　of　the　existence　of　this　fertile　cause　of　failure；　yet　some　undue　or　unexpected　strain　will　rend　and　disclose　the　shut…up　scoriae；　and　probably　end　in　some　fatal　break…down。　　The　annexed　figures　will　perhaps　serve　to　render　my　remarks　on　this　truly　important　subject　more　clear　to　the　reader。

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Fig。1　represents　an　imperfectly　prepared　surface　of　two　pieces　of　malleable　iron　about　to　be　welded。　　The　result　of　their　concavity　of　form　is　that　the　scoriae　are　almost　certain　to　be　shut　up　in　the　hollow　part；as　the　pieces　will　unite　first　at　the　edges　and　thus　include　the　scoriae；　which　no　amount　of　subsequent　hammering　will　ever　dislodge。　　They　will　remain　lurking　between；　as　seen　in　Fig。2。　　Happily；　the　means　of　obviating　all　such　treacherous　risks　are　as　simple　as　they　are　thoroughly　effective。　　All　that　has　to　be　done　to　render　their　occurrence　next　to　impossible　is　to　give　to　the　surfaces　we　desire　to　unite　by　welding　a　convex　form　as　represented　in　Fig。　3；　the　result　of　which　is　that　we　thus　provide　an　open　door　for　the　scoriae　to　escape　from　between　the　surfaces；as　these　unite　first　in　the　centre；　as　due　to　the　convex　form；　and　then　the　union　proceeds　outwards；　until　every　particle　of　scoriae　is　expelled；　and　the　union　is　perfectly　completed　under　the　blows　of　the　hammer　or　other　compressing　agency。　Fig。　4　represents　the　final　and　perfect　completion　of　the　welding；　which　is　effected　by　this　common…sense　and　simple　means；that　is；　by　giving　the　surfaces　a　convex　form　instead　of　a　concave　one。

When　I　was　called　by　the　Lords　of　the　Admiralty　in　1846　to　serve　on　a　Committee；　the　object　of　which　was　to　investigate　the　causes　of　failure　in　the　wrought…iron　smith　work　of　the　navy；　many　sad　instances　came　before　us　of　accidents　which　had　been　caused　by　defective　welding；　especially　in　the　vitally　important　articles　of　Anchors　and　Chain　Cables。　In　the　case　of　the　occasional　failure　of　chain　cables；　the　cause　was　generally　assigned　to　defective　material；　but　circumstances　led　me　to　the　conclusion　that　it　was　a　question　of　workmanship　or　maltreatment　of　what　I　knew　to　be　of　excellent　material。　　I　therefore　instituted　a　series　of　experiments　which　yielded　conclusive　evidence　upon　the　subject；　and　which　proved　that　defective　welding　was　the　main　and　chief　cause　of　failure。　　In　order　to　prove　this；　several　apparently　excellent　cables　were；　by　the　aid　of　〃the　proving　machine；〃　pulled　to　pieces；　link　by　link；　and　a　careful　record　was　kept　of　the　nature　of　the　fracture。　　The　result　was；　that　out　of　every　100　links　pulled　asunder　80　cases　clearly　exhibited　defective　welding；　while　only　20　were　broken　through　the　clear　sound　metal。　　This　yielded　a　very　important　lesson　to　those　specially　concerned。


1845。　Introduction　of　the　V　Anvil。

In　connection　with　my　Steam　Hammer；　when　employed　in　forging　great　cylindrical　shafts；　I　introduced　what　I　termed　my　V　anvil。　Its　employment　has　most　importantly　contributed　to　secure　perfect　soundness　in　such　class　of　forgings。

In　the　old　system　of　forging　cylindrical　shafts；　the　bar　was　placed　upon　a　flat…faced　anvil。　　The　effect　of　each　blow　of　the　hammer　upon　the　work　was　to　knock　the　shaft　into　an　oval　form　（see　Fig。　1）；　and　the　inevitable　result　of　a　succession　of　such　blows　was　destruction　of　the　soundness　of　the　centre　or　axis　of　the　shaft。

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In　order　to　remedy　this　grave　defect；　arising　from　the　employment　of　a　flat…faced　anvil；　I　introduced　my　V　anvil　face　（see　Fig。　2）；　the　effect　of　which　was；　that　the　dispersive　action　of　the　blow　of　the　hammer　was　changed　into　a　converging　action；　which　ensured　the　perfect　soundness　of　the　work；　while　the　V　or　fork…like　form　of　the　angle　face　kept　the　work　steadily　under　the　centre　of　the　hammer；　allowing　the　scale　or　scoriae　to　fall　into　the　apex　or　bottom　of　the　V；　which　thus　passed　away；　leaving　the　faces　of　the　angle　quite　clear。

This　simple　and　common…sense　improvement　was　eagerly　and　generally　adopted；　and　has　been　productive　of　most　satisfactory　and　important　results。


1847。　A　Spherical…seated　Direct…weighted　Safety　Valve。

Having　been　on　several　occasions　called　to　investigate　the　causes　of　steam　boiler　explosions；　my　attention　was　naturally　directed　to　the　condition　of　the　Safety　Valve。　　I　found　the　construction　of　them　in　many　cases　to　be　defective　in　principle　as　well　as　in　mechanical　details；　resulting　chiefly　from　the　employment　of　a　conical　form　in　the　valve；　which　necessitated　the　use　of　a　guide　spindle　to　enable　it　to　keep　in　correct　relative　position　to　its　corresponding　conical　seat；　as　seen　at　A　in　Fig。　1。　　As　this　guide　spindle　is　always　liable　to　be　clogged　with　the　muddy　deposit　from　the　boiling　water；　which　yields　a　very　adhesive　encrustation；　the　result　is　a　very　riskful　tendency　to　impede　the　free　action　of　the　Safety　Valve；　and　thereby　prevent　its　serving　its　purpose。

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With　a　view　to　remove　all　such　causes　of　uncertainty　in　the　action　of　this　vitally　important　part　of　a　steam　boiler　I　designed　a　Safety　Valve；　having　a　spherical　valve　and　corresponding　seat；　as　seen　in　B　C；　Fig。　2。　　This　form　of　Safety　Valve　had　the　important　property　of　fitting　to　its　bearing…seat　in　all　positions；　requiring　no　other　guide　than　its　own　spherical　seat　to　effect　that　essential　purpose。　　And　as　the　weight　required　to　keep　the　valve　closed　until　the　exact　desired　maximum　pressure　of　steam　has　been　attained；　is　directly　attached　to　the　under　side　of　the　valve　by　the　rod；　the　weight；　by　being　inside　the　boiler；　is　placed　out　of　reach　from　any　attempt　to　tamper　with　it。

The　entire　arrangement　of　this　Safety　Valve　is　quite　simple。　　It　is　free　from　all　Lever　Joints　and　other　parts　which　might　become　clogged；　and　as　there　is　always　a　slight　pendulous　motion　in　the　weight　by　the　action　of　the　water　in　the　boiler；　the　spherical　surfaces　of　the　valve　and　its　seat　are　thus　ever　kept　in　perfect　order。　　As　soon　as　the　desired　pressure　of　steam　has　been　reached；　and　the　gravity　of　the　weight　overcome；　the　valve　rises　from　its　seat；　and　gives　perfectly　free　egress　to　any　farther　accumulation　of　steam。　　It　is　really　quite　a　treat；　in　its　way；　to　observe　this　truly　simple　and　effective　Safety　Valve　in　action。　　After　I　had　contrived　and　introduced　this　Safety　Valve；　its　valuable　properties　were　speedily　acknowledged；　and。　　its　employment　has　now　become　very　general。


1847。　A　Machine　for　cutting　out　Cottar　Slots　and　Key…Groove　Recesses　in　　　　　　　Parts　of　Machinery　by　a　Traversing　Drill。

One　of　the　most　tedious　and　costly　processes　in　the　execution　of　the　detail　par