The Horizontal Steam Turbine For Stationary Plants 1920

the springs (2). The pipe (5) is a steam connection permitting the employment of live steam for sealing purposes. A small Fig. 5. Carbon packing amount of cylinder oil is introduced into this giand to prevent wear of the shaft and to improve the sealing effect of the packing. Labyrinth Packing (Fig. 6) There is a labyrinth packing at the high pressure and another at the low pressure or exhaust end of the turbine. Labyrinth packing consists of rings (1) on the shaft (F), which alternate with sta- tionary rings (2) fixed in the surrounding Fig. 6. Labyrinth packing casing (3). The clearance is small between the stationary rings and the shaft. Leakage is prevented by the small spaces (clearances) between the rings, which makes it difficult for leaking steam from the turbine to pass all the rings in a zigzag way. The high pressure steam that leaks past the rings as far as the pipe (4) is led away through that pipe connection to the condenser, or to an intermediate stage of the turbine. Any of the condensed steam in the form of water that passes the packing is deflected by the baffle ring (Fio, Fig. 4), which throws it by centrifugal force from the revolving shaft. Water is thus prevented from working into the bear- ings, where it would mix with the oil. In a condensing turbine the pipe (4) is used for introducing steam at low pressure into the low pres- sure packing. This is to prevent the leakage of air into the turbine. Air leak- age into the turbine greatly decreases its operating effi- ciency. Water Seal (Fig. 7) The disk (1) is fixed on the shaft (F) and revolves inside the casing (3) into which a constant supply Fig. 7. Water seal packing of water is admitted by means of a pipe con- nection (4). Due to the centrifugal force of the revolving disk the water is thrown to the outside of the circular chamber and forms a water seal (6) making it impossible for steam or air to pass from one side of the disk to the other side. PRINCIPLE OF OPERATION Steam is admitted through the stop valve (Hy, Fig. 4) and passes into the turbine at the high pressure end. It first passes through the blades (A2) of the first stationary disks—the set of smallest diameter—and impinges on the blades (F7) of the first set of revolving disks; it then passes to the second set of stationary disks which directs the flow of steam to the second set of revolving disks—and so on throughout the whole series of blades. In its passage through the turbine the flow of expanding steam loses its pressure 9