COUCH ROLLS

191

The board may be used without a cover, but though the wear of the jacket
is less and the joint is more water-tight, the jacket fills up with size, loading
and fine fibres, and requires frequent cleaning and blowing with the force jet.
The efficiency of the couch roll is greatly reduced, and any saving in covers
is nullified bv the waste of time and extra 'broke'. The flow of water

is

[Robert Fktther md Stm Lit.
PIG. <59.—SUCTION COUCH Ron WORKING ON A MAOTMR MAXJNQ FTME TISSUES AT HIGH SPEED
«
supplied by a spray-pipe close to the guard board, but the spray must not play
on the couch-roll cover, or it will raise the nap and the fibres will be pulled
off by the board. A frequent cause of damage to the cover is that, wfccn
shutting down or starting the machine, bits of pulp or foreign matter stick
to the roll, and become jammed in the board, cutting or scoring the cowt m