204

MODERN PAPER-MAKING

closes a valve in accordance with the quantity of water coming through the
pipe. A great many varieties of steam traps have been put into use of late
years, but they all work on much the same principle, and, unless kept in good
order and regularly cleaned out, are more often than not steam wasters.

Steam and water nozzles without packing are now in general use. The
principal feature of these nozzles is the total absence of packing, all the joints
being carefully machined, and there is an ingenious system of lubrication by
which these joints are kept covered with a thin film of oil, which reduces the
friction to a minimum and keeps them both steam- and water-tight.

There are special patterns for drying cylinders, machine and supercalenders,

M.G. cylinders and boilers,
and they are made for func-
tioning with either water
lifters or syphons.

On a machine where the
cylinders are few and con-
stantly in use, the outlet pipes
may all be connected to one
large pipe and one long steam
trap. But the objection to
this is that the steam blows
back and overheats those
cylinders that are not re-
quired to be very hot, as it is
not advisable to have stop
valves on the outlet pipes.

Steam Circulation Plants.—
The old method of trapping
the steam from each cylinder
or section of cylinders has now
almost entirely given way to a

new method of steam circulation. There are two plants in use, the VJJB.
steam circulation system and the Holmes and Kingcome. The principle of the
VJ.B. is that it injects steam into the cylinder, traps that steam when it leaves
tbc cylinder, separates it from the water, and reinjects the uncondensed steam
again into the cylinder, thus ensuring that all the latent heat of the steam is
made use of in heating the cylinder, and until condensed water passes away
though t&e trap to be returned to the hot well.

Very large saving* in coal ha ve been effected in many mills by the ktrcKlucti
together with vastly improved drying on the paper machines,

[Bcntlcy and Jackson
Fie. 81.—DIAGRAM OF STEAM IN THE DRYING CYLINDER,

AND CONDENSATE COLLECTING TROUGH

of tfa*$