This refers to strength of details, accuracy of foundry work, accuracy of alignment, accuracy of fits, quality of steam joints and flanges, construction of steam pistons and slide-valves, etc., and does not apply particularly to exterior finish.
2. Duplex Only.
a. Only “Standard Duplex pumps” are acceptable.
So-called “Duplex” pumps consisting of a pair of pumps with “steam-thrown valves” actuated by supplemental pistons are not acceptable.
Experience shows that duplex pumps are more certain of starting after long disuse. The whole power of the main cylinder is available for moving a corroded valve or valve rod, whereas on a single pump with a “steam-thrown” valve no such surplus of power is available.
Further, the direct acting duplex has the great advantage over a fly-wheel pump of not suffering breakage if water gets into steam cylinder.
3. Sizes of Pumps.
a. Only the four different sizes given on the [next page] will be recognized for “National Standard” pumps.
The multiplicity of odd sizes of “Trade Pumps” is confusing, and different makers have, in the past, estimated the capacity in gallons according to different arbitrary standards.