Patent GB-340010-A (GB)
Title: Process for the preservation of bones
IPC: C09H1/02
Filed: 1929-09-07
Abstract: 340,010. British Glues & Chemicals, Ltd., and Drew, R. B. Sept. 7, 1929. Manures.-Bones are preserved by reduction while fresh to a finely divided condition, e.g. by cutting into shavings, followed by drying to substantial desiccation. The reduced bones may, prior to drying, be extracted by a solvent, e.g. water containing common salt, to remove blood, fat-splitting enzymes and other undesirable constituents. In one form, Fig. 1, the raw bones are reduced to shavings in a cutting machine a from which they pass through a shoot b to a rotating endless belt c of gauze or other porous material through which warm dry air is caused to pass. The bone material is dried on the bed c and falls into a removal shoot e. The belt c is mounted within a chamber h having non-conducting walls i, hot air being introduced through an opening k into the space enclosed by the belt c, a baffle l being preferably provided to cause the air to pass through the upper portion of the belt to effect the drying and a part f of the lower portion to remove any dried material still adhering to the belt at that point. The air passes from the chamber h through an outlet m. The hot air may be obtained from a chamber n having a heater o, with air inlets 18 on one side and a fan 19 on the other. The air circulation through chamber It may be continued a number of times until the air has absorbed a predetermined amount of moisture. The cutting machine a consists of a cylindrical chamber p divided into two compartments r by a partition q. A member t with slots to accommodate the partition q is movable vertically within the chamber p. A rotating cutter plate u locked to a shaft v closes the lower end of chamber p and is driven by the engagement with teeth on its periphery of a worm 6 rotated, e.g. by a driven pulley 21. The cutters 8, Fig. 2, are clamped by nuts 9 to the cutter plate u and extend through inclined slots 10 therein, the slots being arranged radially and at varying distances from the centre of the plate so that the entire space between the shaft v and the walls of the compartments r is traversed by a cutting edge at least once during one revolution of the plate. The cutters. have an interrupted edge so as to cut narrow shavings from the bones which are pressed thereon by member t. The means by which the member t is forced downwards comprises a screw-threaded sleeve x slidably keyed on shaft v, and engaging an internal screw thread on a toothed wheel 3 a boss 2 on which contacts with member t and forces it downwards on rotation of shaft v. A spring 4 disposed between the boss 2 and an adjustable abutment 5 on shaft v absorbs the upward reaction of sleeve x due to forcing the wheel 3 downwards. To prevent the pressure on the bones increasing beyond a predetermined value, a pinion 22 rotating on a pin supported in a bracket 24 engages wheel 3 and is provided with an adjustable braking collar 23 pivotally attached to the bracket 24 and pressed into contact with the pinion 22 by a spring 25 the pressure of which may be varied by a nut 26. When the bones have been reduced, the part t is raised by links 40, 41, and lever 42 above the inlets 38 through which a fresh supply of bones is added. In a modification (Fig. 4, not shown), the bone material is disposed during drying on a plurality of trays having gauze bottoms and disposed one above another, heated air being passed upwards through the trays. The material may be treated, before drying, with water or other solvent in a vessel 30, Fig. 5, having a perforated false bottom 31 under which the solvent is introduced through a twoway cock 34, an overflow pipe 32 having a strainer 33 and a manhole 36 for removal of the material. To allow the material to settle, the solvent is allowed to flow back at intervals by allowing it to pass away through a drain pipe 35 by operating cock 34. In another form, Fig. 6, the washing is effected in a vat 12, the material being carried through and removed from the vat by an inclined endless belt conveyer 13 made of gauze or other material from which the solvent can drain off freely and having transverse strips 14 to retain the material. The solvent enters the vat through a pipe 16 and leaves through an overflow outlet 17 having a strainer to retain solid matter. The treated bone material is odourless and may be stored for a considerable period for further treatment, e.g. for the extraction of grease or the manufacture of glue. The Provisional Specification describes the drying of the bone material by means of a vacuum.