Patent GB-902899-A (GB)
Title: Improvements relating to the degreasing of bones
Inventor: SCHELLENBERG CLIFFORD ROBERTSH
IPC: C09H1/02
Filed: 1957-11-28
Abstract: Cleaned and degreased bones suitable for subsequent use in the production of ossein <PICT:0902899/III/1> <PICT:0902899/III/2> <PICT:0902899/III/3> gelatine are obtained by first fragmenting the bones to dimensions of one-quarter to threequarter inch, cleaning the bones from adhering tissue and reducing the fat content to 5 to 6%, and thereafter circulating the partly degreased fragments in a flow of hot water at 140 DEG -190 DEG F., preferably not above 170 DEG F. from, into, and through a large body of hot water, residual fat being separated by flotation and particles of tissue by settling.  If required, a little caustic soda or detergent may be added to the water.  As shown in Fig. 1, raw bones are fed to crusher 2 and thence to a second crusher 4 before being passed by elevator 5 to preliminary cleaning and degreasing vessel 6 where the fat content is reduced to 5 - 6%.  The partly degreased bone fragments are collected in receptacle 7 and then fed to hopper 10, whence they pass, by elevator 11 to vibrating screen 12.  Small fragments pass out through 13 to be made into meal, fragments of the correct dimensions pass through 17 into receptacle 18, and oversize fragments pass through 14 on to conveyer 15 to be returned to crusher 16 and so once more to hopper 10.  The correctly sized fragments are transferred from container 18 into the main cleaning and degreasing vessel 19, shown in greater detail in Fig. 14. The bone fragments are charged into upper part 71 so that they are supported by perforated plate 73 and are then covered with water of the required temperature.  Stirrer blades 82 maintain the fragments in motion in the water, and arcuate blade 79 serves to sweep fat and scum floating on the surface towards overflow box 80.  The hot water is continuously and vigorously withdrawn through conduit 85 by pump 20 and returned through 88. Trapezoidal blade 83 maintains fine bone and tissue which has passed through screen 73 in motion, and after the fragments have been adequately degreased a slurry of the water with the fine bone and tissue is run off through 91, the cleansed fragments being removed through 70.  A preferred form of cleaning and degreasing vessel is shown in Fig. 2.  In this case the bone fragments are charged through doors 35 and 36 into perforated drum 34 mounted for rotation or oscillation on vessel 31 which is filled with hot water to level 59. Water is withdrawn through 44 by pump 20 and reintroduced through 51. After the fragments have been adequately degreased, normally 30 minutes, the slurry of bone meal, tissue and water is run off through 62.  Doors 35 and 36 in the drum are opened and the fragments contained spilled out through door 64. In general the bone fragments are treated with about three times their weight of water, and the entire volume of water is circulated in about 1 1/2 minutes by the pumps.  The preliminary cleaning and degreasing vessel 6 (see Fig. 1) is suitably similar in construction to the vessel shown in Fig. 2, the pump and conduits for circulating the water being omitted.