i4o MODERN PAPER-MAKING
the shortest possible time, as it is often necessary to shut off stuff in a hurry.
Sometimes a pipe is led from the stuff box to a convenient position, and the
stuff gate made more accessible, but this entails another pipe to clean, or another
source of scale and slime. Very often very large, elaborate stuff boxes are
provided, but all that is really required is a box about 3 feet deep and 3 feet
wide, tile- or copper-lined. Larger than this means waste of stuff when running
out or changing colours.
The overflow from the box should be wide, so that there will not be a great
change in the level of the stuff with the possible variations of the stuff pump.
The overflow shute runs to the chests, with a slide or gate to direct the stuff
to either chest. The whole box and overflow pipes or shutes need very frequent
cleaning. The waste valve of the stuff box should be replaced carefully and
examined by the machineman before he starts to pump up stuff A problem
which confronts the machineman is how he can deal with the stuff in the box
when it is left from Saturday to Monday. The stuff left in the box may be
found to have lost its water by leakage through the stuff gate. He must then
either lift it out or risk having the overflow block up by pumping up fresh stuff
On the other hand, if the stuff gate is quite watertight, the thick stuff will
He on the bottom of the box and may-block the valve after he has started up
the machine.
If the stuff pump has a loose pulley he may stop the pump and let the stuff
run out of the box. If not, he risks broken valves if he shuts the chest valves
to stop the supply of stuff To empty the box after the machine has been shut
down means wasting valuable material.
With a centrifugal pump the chest valve may be shut without risk of any
damage, but in both cases there still remains the contents of the pipe from the
pump to the stuff box. This shoots up, on starting again, in a thick column
and makes a mess all over the place.
The best way out of the difficulty is to try to run a chest empty when shutting
down on Saturday. The hose-pipe may then be run into the chest, or the
beaterman may put down a flush of water and clear the stuff through the pipe
and pump, and run it over the machine. In any case, when running out a
chest and changing colours, when it is necessary to shut and wash up, the pipes,
pump, stuff box, etc., should always be emptied and all the fibre possible
run over the wire. The fibre recovered in this way may be run up the press
rolls and taken back to the beating room. A very valuable help is a water
connection between the chest valve and the stuff pump; the valve may be
shut and the water run into the pipe, thus driving the stuff in front of it to
the stuff box.
The Stuff Gate.—This important valve is not apparently considered worthy