GB378803A - Improvements in and relating to overload steam turbines - Google Patents

Abstract

378,803. Turbines. BROWN, E., 8, Bahnhofweg, Baden, Switzerland. Feb. 24, 1932, No. 5498. [Class 110 (iii).] To reduce friction and ventilation losses in the overload low-pressure sections 5 of a steam turbine which are run in parallel with one or more normal load low pressure sections 3 in series with high pressure sections 1, 2 when running idle with the valve 6 closed, the condenser, preferably a surface condenser, at least during non-operation of the overload low pressure sections, is subdivided into a primary condenser 8, into which the normal load sections 3 exhaust, and a secondary condenser 9, with which the overload sections 5 are in sole connection and in which, by specifically low heat loading or by supply of cooling water at lower temperature than that supplied to the primary condenser, a higher vacuum is formed and maintained. The secondary condenser 9 may be wholly or partly cooled by cold make-up water from cooling towers. When the overload sections 5 are not operating, the cooling water pumps of the secondary condenser 9 are partly or wholly supplanted by those of the primary condenser 8, cooling water being diverted from the latter through the connection 15, the valve 18 being closed. The air extractors of the secondary condenser 9 during normal load running deliver to an intermediate vacuum, preferably to that in the primary condenser or in the connection of the latter with its air extractor or in an intermediate stage of the extractors of the primary condenser 8. Cooling steam from the secondary condenser 9, or from a main low pressure exhaust, or a stage of the normal load low pressure sections, is circulated, preferably by the fan action of the blading, through the non-operative L.P. sections and over the cooling surfaces of the condenser to remove the heat generated by the idle running rotors. The initial volume of the cooling steam is proportioned to the blade areas of the idle overload low pressure section that the kinetic energy derived from the heat drop between the primary and secondary condensers, or between an operative low pressure stage and the secondary condenser, as to eliminate a part or the whole of the ventilation &c. losses.