14
(8).
23. Cylinders, Fistons & Piston Rods. The cylinders, with
their piston valves, are to be outside the frames.
The stoam ports and passagos are to be designed with
special attention to securing a free and unobstructed
palth for exhaust steam, all sharp bends and sudden
The Fiston Changes of c100s-section alc to be avoided.
Heads are to be of picescd stool, Litted with two cast
iron rings. The piston-rods which aic to have tail
Guds, arc to be of class "" stoci, the seats for thic
piston heade are to be folmed with a taper of 1 in 6,
straight though with no collars, and the seats to the
crossheads are to be tapered i in 20. The pistol leads
are to be secured on the rods with gumetal nuts and
steel cottars, similar to those shown on Drgs. Nos..4472
1100
156 & 137 Requ. No. 251/1 modified to suit the smaller
didacter of cylinders. The tail-rod glands, bushes,
packing, covers etc., and also the cylinder cover cat ings
which are to be finished biight are to be si uilar to those shown on Drg. No.4472/136, Reg. No. 251/1, mouifiod
as necessary to suit the smaller lacter of cylinders.
24. Metallic Facking. mütallic packing at su¡ piiod by the
United ingdom Fatout Metallic Facking Company, is to
bo litted lol the piston rods. The packing 101 the
valve spinales it to be the samc at that shown on Drg.
No.. 4472/138, Requ. No.20lj 1.
25. Fiston Valves. The design of the piston valves is to
follow that shown on Dig. No.2.4472/ 145, Reym. 251/1.
Renowable limers of tough cast iron arc to be fitted
in the steam chests and the steam poite in the limore
are to bc tiiangular in Shape similar to those choWII
o Dig. No. 4472/144.