Patent GB-209674-A (GB)
Title: Improvements in or relating to the production of leather
IPC: C14C15/00
Filed: 1923-06-13
Abstract: 209,674. Forselles, A. J. L. af. June 13, 1923. Impregnating-apparatus for, vacuum; vats, construction of; extracts, making and treating; treatment preliminary to tanning. - Apparatus for making leather comprises a series of tanning drums connected to containers for tanning extract in such a way that the drums can be filled either by pumping or, by means of a vacuum-producing apparatus, by sucking, or by both. The tanning extract is prepared in a series of vessels in communication with one of the extract-containers, which is connected to a vessel in which extract may be concentrated in vacuo, this vessel in turn being connected to minor containers attached to the tanning drums so that concentrated extract can be introduced into each drum as desired. The tanning drums are of special construction, and both they and the extraction-vessels are heated by steam from a common source. The tanning drums 168 are connected by pipes 170, 171 with the exhauster 165, a collector 172 being interposed from which extract withdrawn by the vacuum can be drained by suitable manipulation into the basin 186, in which tanning extract prepared in the vessels 176 - - 178 is also collected. The drums are filled with extract from the basin 186 either by means of the pump 199 and pipes 198, 200, 201, or by suction through the pipes 204, 206. Extract from the basin 186 can also be drawn by way of pipe 193 into the vessel 195 for concentration, the concentrated extract being either returned to the basin 186 by way of pipe 197 or transferred to the drums by way of pipe 209 or pipe 215. The pipe 209 communicates with the pipes 200, 201 and by suitable manipulation of the valves enables concentrated extract to be sucked into the drums by the vacuum prevailing therein. The pipe 215 is provided with branches 217, Fig. 4, which convey the concentrated extract to minor containers 212, one of which is attached to each drum and from which extract is sucked into the drums by way of pipes 213 and valves 214. The pipe 215 communicates also with another extract-container 208 in which stronger extract is stored than in the basin 186, and a pump (not shown) is provided to enable the containers 212 to be filled from the basin 208, if desired. Extract from the drums 168 can be drained into either of the basins 186, 208. Tanning extract is prepared in vessels 176 - - 178, Fig. 2, water passing through the vessels in the order named and the extract finally discharging into the basin 186. The vessels are heated by coils 192 through which steam or hot water is passed by way of pipe 188 from the boiler 187. A series of extract-concentrators 181 - - 183, Fig. 3, connected to the exhauster and the boiler, is provided in which extract produced in excess of requirements may be concentrated to any desired extent. The boiler 187 serves also as the source of heat for the tanning drums 168, a branch 219, Fig. 4, leading from the pipe 188 into the lower part of each drum beneath the false bottom 317. Each drum is further provided with a thermometer 351, a pressure gauge 352, illuminating means 353, and an apparatus 350 from which the strength of the extract in the drum is read off ; a glass disc 315 is arranged in the lid 304. The hides are supported in the drums from rods 354 forming part of frames 1, Fig. 7, which rest on supports 2 and vary in shape according to whether whole or half hides are being treated. Prior to tanning the hides may be subjected to lime treatment in a vessel 167, Fig. 1, connected to the exhauster 165, and similar drums for washing the hides may be provided.