BACKWATER RECOVERY

353

intake pipe and intimately mixed with the back water in the nozzle. It
then passes to a wooden box (3); much froth is made in this box owing to the
excess air escaping, and the air-intake pipe is led into this froth from a

[ Watford Engineering Works Ltd.
FIG. 153.—THE ADKA PATENT SAVE-ALL
The cycle of operations is as follows:
The back water is pumped by pipe 1 through injector 2 to the tank 3 (the injector aerates the back water and by this
means carried up any loading material contained in it).
From tank 3 the back water is drawn up pipe 4 to the main tank 5. The fibres being aerated, plus the vacuum in tank 5,
causes the flow up pipe 4.
The revolving pipe 6, with its sucker 7, is the suction pipe coupled to the vacuum pump 8.
The thin layer of fibres floating upon the surface of the back water in tank 5 is sucked off by the sucker 7. After being
skimmed, the clarified water falls to discharge tank 9 by pipe 10.
The air and recovered stock are drawn towards pipe 11, the air ascending up the pipe 12 to the vacuum pump 8. The
recovered stock descends in barometric leg 11 to the centrifugal pump 13 and is pumped to the stuff chests or preferably
the mixing box. Both pumps are driven by motor 14. The compensating pipe 15 allows for a constant discharge from the
centrifugal pump 13.
Pipe 16 is to fill the tank when starting up; 17 reverses the flow of liquid for washing-out purposes.
Sight holes in cover with electric lamps allow for inspection of inside of tan? 5.