Patent GB-453651-A (GB)
Title: Improvements in continuous automatic centrifugal separating machines
IPC: B04B11/08
Filed: 1935-02-15
Abstract: 453,651. Centrifugal machines. AMERICAN CENTRIFUGAL CORPORATION, 70, Pine Street, New York, U.S.A. Feb. 15, 1935, No. 4979. Convention date, Feb. 21, 1934. [Class 23] A centrifugal machine for the treatment of sewage and like material has a basket 13 with imperforate walls and openings in its base for the discharge of separated solids. The liquid passes through a sieve plate 43 at the top to radial seepage channels, and the basket is driven through bevel gearing by a high speed motor for purging and by a low speed motor for cleaning. The bottom section 1 of the casing has inner and outer flanges 24, 25 forming an annular trough 26 for the reception of the liquid discharged from the basket; an outlet pipe 27 leads from the trough. This section 1 is supported by inclined walls 12 rising from a base with tapered end portions forming platforms 19, 20 for the support of the high and low speed motors 88, 89. A shaft 70, Figs. 1, 13 is connected by overrunning clutches 86, 87 to the motors 88, 89 and this shaft carries the sleeves and gearing through which the basket is rotated. The gearing is lubricated by oil supplied from a tank 80 by a pump 78. The clutch 86 has an outer cylindrical member 86<a>, Fig. 15, secured to the high speed motor shaft and an inner member 86<b> with a number of peripheral cam or clutch faces 86<c> for engagement with spring-pressed rollers 86<d> interposed between the two members. The clutch 87 is of similar construction. The material is supplied to the machine through the pipe 92 under the control of a valve 93 which may be operated by a hand wheel 100 or by an electric motor 101, Fig. 2. The feed pipe 92 branches into two parts 103 which form continuations of the tubes 104 in the casing part 2, and dependent tubes 105 with flattened widened nozzles 106 convey the material to the lower part of the basket 13. The branches of the feed pipe have openings 107 for cleaning purposes; they are normally closed by caps 110 and have branch pipes 111 for the supply of chemicals, steam or the like for treatment of the material in the machine. Hollow vertical shafts 113 extend into the basket in quadrature with the pipes 105 and carry hollow scrapers 114 which can be turned into engagement with the deposit in the basket. The upper ends of the shafts 113 have arms 129 with pins 131 working in openings in blocks mounted to slide transversely in openings 134 in a sliding bar 135. One end of this bar slides in a guide 137 while the other end is connected to a screw 139 engaged in a threaded sleeve 141 which can be rotated by a motor 146, Fig. 1, through bevel gearing. By these means, the scrapers 114 may be brought into engagement with the deposited solids, or brought to the centre of the basket as shown in Fig. 9. Nuts 151 limit the movement of the screw and prevent the scrapers from actually touching the basket wall. Each scraper 114 has a blade 118 detachably secured to its outer edge and provided with teeth 119. A number of jet openings 125 are provided behind each blade for the purpose of cleaning the blades and the basket wall by means of compressed air supplied through the hollow shafts 113. The top plate 30 of the basket 13 has a recess in which is fitted a screen plate 43 with a number of ribs bounding a number of radial channels which communicate with the inclined apertures 45 in the screen plate, and also with the discharge apertures 47 in the basket flange. A screen 49 is arranged beneath the plate 43 and has a group of small perforations 50 arranged beneath each aperture 45. When the vertical bolts 5 which secure the casing sections 2, 3, 4 are removed, the sections 2, 4 with the mechanism for feeding to and discharging from the basket can be lifted as a complete unit. At the commencement of the operations, the slow speed motor 89 and the motor 146 are started to rotate the basket slowly and to move the scrapers 114 towards the basket wall. The motor 146 is then reversed to restore the scrapers to the central position. The high speed motor 88 is then started and the clutch arrangement permits it to overrun the motor 89 and to drive the basket at a high speed, while the motors 88, 146 are switched off. The valve 93 is then turned on to admit material to the basket 13 and the solids are deposited on the wall while the separated liquid passes through the screen plate apertures 45 to the casing part 3, the trough 26, and the outlet 27. The valve 93 is closed after a predetermined time and the cycle of operations is repeated. When the motor 146 moves the scrapers 114 outwards the deposited solids are removed and drop through the holes 38 in the base of the basket.