GB1058053A - Improvements in or relating to the treatment of blood - Google Patents

Abstract

In an apparatus for treating animal blood to render it suitable for further handling, the blood is pumped at a controlled rate from a storage tank (which may include a mechanical stirrer) to the base of a vertical duct (which provides a liquid head), where steam is injected into it from lateral apertures in a short pipe extending upwards into the duct. Steam is also admitted to a manifold surrounding a perforated part of the duct a little above the first-mentioned steam admission, and valves are provided to permit controlled inflow at either or both locations. A mixture of (a) a homogeneous mass consisting of blood solids combined with water and (b) free water, is formed, and passes from the top of the duct downwards, perferably to the interior of a rotary perforate drum rotating about an inclined axis above a trough, also inclined. Free water passes through the drum into the trough, while the remaining mixture flows down into a hopper feeding from above into a horizontal compression-and-extrusion press. The cage of the press (to the right of the hopper) preferably consists of an annular assembly of narrowly-spaced horizontal parallel bars and is closed at the outer end by a hydraulically-retractable cover (which may be perforate). Pressure is applied (by a hydraulically-actuated piston located to the left of the hopper) in two stages-first a lower pressure to express part of the water, then a higher pressure, to express further water and to cake the mass, after which the cover is retracted and the cake ejected. In another embodiment the rotary drum is omitted, the free water in that event draining away through the cage of the press. Pneumatic devices may be provided for conducting each cycle of operations in a timed sequence.