158 MADRAS FISHERIES BULLETIN VOL. XIII, 



Where hydraulics are used the boiled fish is usually allowed 

 to drain in draining tanks, and when sufficiently drained to be 

 fairly solid, the stuff is forked out into cylindrical iron cages (tubs 

 or "curbs") on wheels running on rails; these are run underneath 

 a stationary press-head against which they are forced by a hydrau- 

 lic ram below them; after being sufficiently pressed the ram is 

 lowered, and the tub is wheeled away to discharge its press-cake 

 which falls to the basement below. The oil and water from the tub 

 fiow on to the cement floor and also pass by pipes to the receiv- 

 ing tanks in the basement. The tubs, usually about 3 feet high 

 and wide are made of stout rectangular iron rods or slats securely 

 bound together by strong hoops ; between each slat there is a 

 narrow interstice through which the oil and water are forced : in 

 the centre there is frequently a hollow core about 12 inches in 

 diameter, similarly built up of slats with interstices which 

 provides an exit for the fluids from the centre of the mass. The 

 tubs are slightly coned as to be a little wider at the bottom than 

 the top ; this enables the press cake to be readily forced out by 

 pressure from above. 



22. The continuous steam press is a horizontal tapered cylinder, 

 about 12 to 18 feet in length, built up of steel rods or slats, and 

 provided with a tapered Archimedean screw built up on a hollow 

 revolving shaft which traverses the cylinder from end to end ; as 

 the shaft revolves the screw forces the material forward from the 

 feeding hopper to the discharge end, the pressure being caused by 

 the gradual tapering of the cylinder so that the material is strongly 

 compressed and the fluids forced out through the interstices of the 

 slats; the pressure is sometimes regulated by a cone-shaped block 

 which can be so adjusted as to lessen or increase the discharge 

 aperture. The whole press is of the nature of the oil press known 

 in India as Anderson's oil expeller. Steam can be introduced by 

 the hollow shaft so that the material is kept hot and pasty. It is 

 said the larger of these presses will efficiently press up to 100,000 

 fish (weighing when raw about 30 British tons) per hour ; the smaller 

 will press half that weight. The power required is heavy, being 

 50 and 35 I.H.P., respectively. The press cake as it leaves the 

 press is said to contain about 4 per cent oil, 46 of water, and 50 of 

 scrap. 



23. The advantages of the continuous press are the saving of 

 time and labour since the cooked fish are brought directly from the 



