GB131428A - Improvements in or relating to Steam Turbines. - Google Patents

Abstract

131,428. Guy, H. L., and British Westinghouse Electric & Manufacturing Co. Aug. 16, 1918. Motor power plant; cooling parts. - In turbines comprising sections adapted at times to rotate idly, steam for cooling is supplied to these idly rotating sections by a special pipe or passage, as distinguished from a channel in a packing-gland through which leakage steam can be supplied from one section to another. The cooling steam may be taken from an operative turbine section in which it has been cooled as a result of doing work. Fig. 1 shows highpressure ahead and reverse sections 4, 5 on one shaft and low-pressure ahead and reverse sections 6, 7 on another shaft. A pipe 10 having a handcontrolled or non-return valve 11 permits steam to pass from the operative section 4 to the idle reverse sections 5, 7. When the reverse sections are operative, a valved pipe 13 leads steam to an intermediate stage of the idle ahead section 4. Another valved pipe 14 may supply steam to the idle ahead section 6. In some cases, a valveless pipe 17 may be arranged to supply steam for cooling from the ahead to the reverse sections or vice versa, depending on which sections are operative, the ends of the pipe 17 being so positioned that a greater quantity of steam is passed from the reverse sections to the idle ahead section when the turbine is going astern than when the opposite conditions prevail, assuming that the disk friction and windage of the ahead section is greater than that of the reverse section. The pipe 10 may be dispensed with by designing the gland 21 to provide sufficient leakage steam to cool the smaller reverse sections when running idle, additional steam for cooling the larger ahead sections when running idle being supplied by a pipe such as 13. Applications of the invention to a turbine comprising cruising and full power sections and to a combination of a back-pressure turbine and a high-pressure turbine are described.