Patent GB-655786-A (GB)
Title: Improvements in and relating to the lifting of salt in salterns or salt gardens
IPC: E21C47/00
Filed: 1948-11-19
Abstract: 655,786. Endless conveyers. COMPAGNIE SALINIERE DE LA CARMARGUE. Nov. 19, 1948, No. 30081. Convention date, Jan. 8. [Classes 78 (i) and 78 (iv)] In an installation for lifting salt in salterns, the layer of salt is lifted by means of one or more shovels mounted on a travelling structure which moves backwards and forwards to remove the salt in strips and convey it away. The travelling structure consists of an endless track vehicle R, Figs. 7 and 8, which is provided with two shovels P and P<1> facing in opposite directions, each shovel being mounted by means of a pair of freely articulated links d, Fig. 2. The shovels have a flat base p and upwardly curved upper surface p<3> flanked by side shields p<2>. The curve of the surface p<3> is such as to cause a strip of salt lifted by the shovel to break at the point e. The side shields p<2> are tapered to a point at the leading edge and to further reduce friction have a laterally enlarged portion at the leading edge shown at p', Fig. 4. The nose p<1> of the shovel is also pointed, the point being disposed upwardly above the ground level so as to avoid digging any ground due to slight deformations therein. The exact height of the point is important as it must not dig upwardly into the salt layer. The optimum height for ground surface withstanding a maximum pressure of about 4.3 lbs./sq. inch is in the order of # inch. Each shovel delivers the salt to an endless belt R<1> which passes it to a transverse belt R<2> also supported by the vehicle R. The salt passes from the latter belt to a long sectioned belt T mounted on transverse endless tracks, which delivers the salt via a loading conveyer C into trucks W outside the salt bed, Fig. 8. The procedure for operating on a salt bed is first to cut two long lanes a7, a<6> transverse to the subsequent direction of cutting, these being disposed the length of the vehicle R from each side of the bed. The vehicle R is then operated in accordance with the arrows 0 to 9, Fig. 8, so as to remove all the remaining salt without waste, by proceeding in this fashion from one end of the bed to the other. As the long conveyer sections T are arranged parallel with the cutting edge of the salt layer the end of belt R<2> will be above conveyer T during the whole of a travel of the shovels but will move away on shifting the shovels to detach a following strip. The conveyer sections T and the loading conveyer C may be shifted to follow this movement by means of electric motors operated in synchronism and deriving power from a generator E associated with the conveyer C. However, in order to avoid moving these conveyers at the end of every travel, the belt R<2> is provided at its delivery end with a rotatable directing shoot r<6>, Fig. 12. A cable attached at one end to the belt conveyer frame is passed over a pulley on a depending arm r7 pivoted at its upper end to the frame, the cable thereafter being passed around the shoot and secured to a drum on a shaft geared to a counterweight. The arm r<7> is thus pressed against a longitudinal rail t<1> on the sections T and as the shovelling vehicle moves away arm r<7> swings so as to rotate the shoot to direct the salt further back, so that it still falls on to the conveyer T. The loading conveyer C, Fig. 15, has a hopper at both ends and the discharge hopper c<4> is provided with two oppositely directed shoots c<5> and c<6>, Fig. 17. These shoots have valves controlled by trip levers c<9> and c<10> which are operated by the trucks in passing so as to maintain a constant flow of salt while preventing salt being fed between two trucks. When one salt bed is completely cleared the equipment is moved across to another prepared bed, the conveyer sections T being preferably provided with bogies t<2>, Fig. 11, for this purpose, the bogies being normally retracted but capable of being lowered so as to operate at right-angles to the endless tracks.