GB168946A - Improvements in or relating to steam turbines - Google Patents

Abstract

168,946. Guy, H. L., and Metropolitan- Vickers Electrical Co., Ltd. May 10, 1920. Cooling parts. - In steam turbines, wherein some or all of the moving blades of a section or element are unsymmetrical, special pipe connections are provided so that the pumping action of s u c h blades, which occurs when the section is rotating idly and in the opposite direction to its normal one, is utilized to provide a continuous circulation of cooling steam through the idly running sections in a direction opposite to that in which the driving steam is caused to flow. For example, in a turbine having forward and reverse turbines 1, 2 of the. reaction type on the same shaft, a valved pipe 6 connects the inlet end of the turbine 1 with the exhaust casing 5 so that when the reverse turbine 2 is being normally operated and the ahead turbine 1 is rotating idly, the pumping action of the turbine 1 causes steam to circulate therethrough from the exhaust casing 5 to the inlet and back through the pipe 6 to the exhaust casing, the valve 7 being opened for that purpose. For cooling the reverse turbine when running idly, similar means may be provided, or leakage steam may be used, or the means described in Specification 131,428. The steam led away from the idly running turbine section may in some cases be led to the exhaust of another turbine, or to a feed-water heater, or to a low-pressure stage to do work. The cooling steam supplied to the idly running section may be drawn from a low-pressure stage or the exhaust of another section. Specification 135,102 also is referred to.