DRY FELTS

as condensation on any cold parts of the machine frame and roof and walls
of the machine house. This causes damage to steel work, and falling drops of
moisture, which are very troublesome when they fall on to the paper machine.

Several methods have been put forward to tackle this question of the con-
ditioning of dry felts, but the one which seems to be the most successful and
which is very satisfactory in use is that known as the 'Happer' patent felt drying
roller. These rollers, which are illustrated in Fig. 85, can be put on in con-
venient places among the drying cylinders, and their construction is such that,
as the felts pass over the roller, the heat and moisture-laden air are drawn
right through the felt into the inside of the roller and conveyed by fan and

fttAJUM*

FIG. 85.— THE 'HATOBR* PATENT Day RBLT DKING CTUNDEB
(The iBnstratksn shows a complete section of the rcfl)

delivery duct out of the machine house. In addition, the rollers are wound
with a bronze wire in such a way that wandering of the felt is greatly reduced.

It will thus be seen that this method not only conditions the felt, but has
the added advantage of removing some of the moisttire4aclen air from the room,
or at least it does iK>t allow this moisture-laden air to be blown into the room.

By placing a number oŁ these rollers at suitable positions among the drying
cylinders the felts are maintained at a modi higher average standard of dryness

than can possibly be attained by some heated cylinders, and there is not so much
danger of the browning or burning of the felts. The felts are evenly dried
across the fbB width of the web, and the moisture is drawn right through
thereby keeping the felt in much better condition, and more open and porous.