. Railway mechanical engineer . h roads the ferrulesbetween the tubes and the tube sheet, it is not the practiceon the North Eastern. The tubes extend through the copper Al-gvst, RAILWAY MECHANICAL ENGINEER 511 tube sheet ^ in for beading, and about U i- through the piece as it would be impossible to place the valve in posi front tube sheet. Tlie tubes are rolled by a three rollerexpander driven by a pneumatic portable machine and arebeaded on the iirebox end only, with the exception of thestay tubes which are beaded on both ends. The ends ofthe superheater flues extending through th
. Railway mechanical engineer . h roads the ferrulesbetween the tubes and the tube sheet, it is not the practiceon the North Eastern. The tubes extend through the copper Al-gvst, RAILWAY MECHANICAL ENGINEER 511 tube sheet ^ in for beading, and about U i- through the piece as it would be impossible to place the valve in posi front tube sheet. Tlie tubes are rolled by a three rollerexpander driven by a pneumatic portable machine and arebeaded on the iirebox end only, with the exception of thestay tubes which are beaded on both ends. The ends ofthe superheater flues extending through the firebox tubesheet are machined on the outside and care is taken to pre-vent any scale or foreign matter from working in betweenthe sheet and the flue. These flues are then expanded bya special five roller expander and beaded as in the case ofthe small tubes. The Xnrtli Eastern has a particularly well equipped boiler tion. This is overcome in the Lockyer valve by passingthe Idwer portion of the vah-r through the opening at the. Fig. 12- ■Lockyer Double Beat Valve Showing Assembled Valveand Separate Parts shop which is of sufticient capacity to more than take careof the needs of the road. Special AttachmentsAmong the attachments to this locomotive may be men-tioned the Lockyer double-beat throttle valve, designedby N. C. Lockyer, the works manager at Darlington. Thisis shown in Figs. 12 and 13. The purpose of this valveis to obtain a more nearly balanced valve than is possiblewith the ordinary construction of double seated valve. Inorder to do this it has been necessary to split the valve bodyinto two parts as indicated in the drawing and joint between these two parts is a carefully made steamtight fit. In this particular case the diameter of the upperand lower valve seats are exactly the same, being 6^ , of course, could not he obtained with the valve in one
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
