Compressed Air Work And Diving 1909

Ö2 COMPRESSED AIR WORZI when resting at both ends 011 rock or other hard ground and unsupported in the middle. Above 26 ft. 6 in. the caisson was a shell only, and therefore hacl to be strutted with timbers varying from 15 by 15 in. to 12 by 12 in. Access to the working chaniber was obtained by three shafts. The shafts were of novel design, being, in fact, two shafts run into one (see Figs. 10 and 11) and separated by an iron ladcler constructed of 2-in. wicle flats riveted to the sides of the shaft by angle bars running the whole length of the shaft on one side, and by short cleats on the other. By this ladder the men descendecl inside the small shaft, which was 2 ft. in diameter. The other portion, 4 ft. in diameter, was for material. An angle bar ran the length of the laclcler riveted to the centre of the flats, and acted as a protection to the fingers and feet of the men, should they happen to be in the shaft at the same time as a bucket. The lock (see Fig. 11) was circular, 8 ft. 6 in. in diameter by 6 ft. high. The entrance chamber was D-shaped, and boltecl on to the outsicle of the lock, the joint between the two being made with red lead. The air pressure was raisecl and lowered from the outsicle by levers, and from the inside with keys by persons authorised to use them. The special feature of the lock was the bucket chamber, which was 3 ft. in diameter and 5 ft. 6 in. high. This chamber hacl a cloor which opened downwards, and which was closecl after a bucket hacl enterecl by a wire bonel and hook, which was fastened to a lug 011 the cloor by hand each time the cloor was closecl. The bond passed round a drum which was fixed on a shaft driven by a motor placed on the outsicle of the lock and put into gear by a friction clutch. The boncl 011 which the bucket was hung was 1 in. diameter, and passed through a stuffing box in the lid of chamber. This