Patent GB-1059781-A (GB)
Title: Pulp refiner
IPC: D21D1/30
Filed: 1963-08-08
Abstract: 1,059,781. Disc mills; mixing pulps. K. V. THOMAS. Aug. 8, 1963 [Aug. 8, 1962], No. 31306/63. Headings B1C and B2A. [Also in Division E2]. A pulp-reflining system comprises a driving assembly with a shaft 6, Fig. 1, mounted in bearings 12, 13, supported by a main frame 5 forming part of a main structure 2, of which one end has webs 25 forming a stress-receiving member to which may be bolted the casing 1 of one of a variety of interchangeable pulp refining units, the refining surfaces remaining parallel under all loading conditions. As described, the refining disc 15 has surfaces 21, 21a cooperating with fixed surfaces 20, 20a which are secured to the casing 1, and an annular loading head 17 respectively. Radially arranged webs 25 extend outwards from a bearing sleeve 11a, and forwards to support the frame 5 where it joins the front casing 1 along a line 3, so as to prevent a heavy load from misaligning the disc 15 and shaft 6 with the stationary surfaces 20, 20a. The surface 20 is adjustable closer to the surface 21, by hydraulic arms 24 and cylinders 19, and the shaft 6 is axially movable so as to equalize the pressure between the sides of the disc and the non-rotating surfaces 20, 20a. The casing and structure 1, 2 are secured at the line 3. by bolts (40, Fig. 4) and a loading-head guide (41) bolted (42) to the frame (5) holds an annular flexible diaphragm (45) attached to the loading head (17). The loading head is supported by the casing (46), which slides along the top of the guide piece when the loading head (17) is pushed or pulled. A cam follower (22) comprising a roller bearing (47) bolted to the casing (46), slides in a groove in the guide (41), so as to allow axial movement of the casing (46) and loading-head, while preventing rotational movement of the head. In a first modification, two inlets each have a screw feed for transferring material to the grinding surfaces and grinding may be carried out dry, water being subsequently added via an inlet (116 Fig. 16) so that the pulp can be discharged by a pipe (120), the length of time the material is retained between the grinding surfaces being varied by operation of a throttle valve (121). A temperature- or pressure-sensitive probe (114) controls a water valve (119) so as either to maintain a desired temperature in the space (115) between the disc (50) and the casing (1d), or to control the quantity of liquid introduced through the valve in dependence on pressure at the probe. Impellers (50b) attached to the periphery of the disc (50) ensure proper mixing of the liquid with the dry pulp issuing from the grinding surfaces. In a second modification, the shaft is hydraulically controlled but there is only one rotating and one fixed cooperating grinding surface. This type of refiner is further modified by the provision of a separately driven front force-feed-screw (80), Fig. 12, and a handwheeloperated chain-and-sprocket actuator shaft-control system (90, 93, 92). Material pushed into the inlet (81) is distributed by a spreader arm (82) connected to the shaft. The refining-disc includes inner and outer grinding surfaces (86, 85) cooperating with inner and outer stationary parts (86a, 85a). The annular surface (85a) is further manually adjustable by means of threaded shafts (84) positioned in sleeves (87) with a handle (88) and a chain and sprocket system attached to the shafts (84), so as to control the time of grinding, by control of the spacing between the surfaces. In a third modification, the front detachable casing (200, Fig. 17) and the main frame (210) have a pair of opposing annular flanges (202) (212) bolted together. Radial ribs (214) extend from the front bearing sleeve (216) to points on the frame and on the frame flange, and prevent any part of the casing becoming misaligned with the shaft (220) and the rotating disc (240). Material passes into the chamber (206), and via the flange (207) and surface (208) it flows through gaps (231, 231a) formed between the stationary grinding surfaces (230, 233) and the moving surface 242 mounted on the disc (240). It is then collected in the chamber (244) and dishcarged as previously described, the feed path being indicated by broken lines and arrows. Where the flow-pressure is sufficient to displace the disc (240) and shaft (220) a shaft extension (220a) and packing gland (222) are used, in which case the feed is indicated by solid lines with the inlet at the casing opening. Alternatively the magnitude of the pressure is sensed and used to control an hydraulic pressure system via a diaphragm head, to apply a load to the front bearing housing 20 in the forward direction. In a fourth embodiment feed of cold material is by a screw mechanism (310, 312, Fig. 18) and a flinger (314), bolted to the shaft (318), throws material outwardly between the surface of the disc (300) and a ring (320), which blocks the space between the casing (330) and the feed screw tube (311). The ring (320) is removably held by bars (324) which also locate the feed screw (310) in the centre of the refiner casing inlet (350), and support the feed screw tube (311). The ring (320) occupies only part of the area between the casing opening (330) and the feed screw tube (311), and thus provides an annular opening (322) around the inner edge of the tube (311), through which steam can escape when refining hot materials, without disturbing the chips fed to the disc (300). Where large quantities of steam are produced the ring (320) may be removed.