S. S. Welch and Co
S. S. Welch and Co, maker of triple expansion engines, of Plymouth
1888 Description and engravings of non·condensing
triple - expansion marine engines, fitted by
Welch Co., of the Docks Iron Works,
in the new Millbrook steamer Iolanthe.
These engines presented some remarkable features,
'amongst which, it may be mentioned, that packing
rings have been entirely dispensed with both in the
piston val ves and pistons ; the latter, however, have a
series of grooves turned on them to check leakage.
The piston valves are designed so that the glands
through which the valve-rods, pass a r exposed to the
pressure of exhaust steam from the cylinders only, and
do not, therefore, require as tight packing as would
otherwise be necessary. By these devices the engine
friction has been reduced to a minimum and the
engines have run with 24lb. of steam pressure only in
the boiler; though the normal working pressure is
160 lb.
The reversing gear is peculiar, all the valves being
worked off two eccentrics only, rendering the engine
very compact in a fore-and-aft direction. Reversing is
effected by an ordinary spiral slotted sleeve which
alters the position of the eccentrics realtively to the
cranks. ....'[1]
Later became the Millbury Pier Engineering Co.