GB721287A - Improvements in or relating to elastic fluid turbines - Google Patents

Abstract

721,287. Turbines. PARSONS & MARINE ENGINEERING TURBINE RESEARCH & DEVELOPMENT ASSOCIATION. Jan. 12, 1953 [Jan. 8, 1952], No. 588/52. Class 110 (3). An elastic fluid turbine having a separate group of by-passing nozzles or stages the exhaust of which is led to a low-pressure stage in the direct line of flow of the turbine, has the group of nozzles or stages fed with working fluid tapped from an intermediate point at a higher pressure in the direct line of flow of the turbine. In the arrangement shown, Fig. 1, two turbines A and B drive a power shaft through pinions 13, 14. At low powers the valve 7 is shut and steam is admitted at 2 and expands in the turbine A to the point 8 where it is divided, part passes through the low-pressure stages of the turbine A and part-through the same stages of the turbine B: To develop maximum power, the valve 7 is opened and part of the exhaust of the first stage 15 of the turbine A passes through the initial stages of the turbine B. Additional supply nozzles to the turbine A may also be opened. By suitable choice of the point 8 and arranging the turbine so that the flow through the early stages of the turbine B is about twice that through the bypassed stages in the turbine A, the two turbines may be arranged to deliver equal power. In a modification the low-pressure stages of the turbines A and B are arranged in one casing and the high-pressure stages in another. In a further modification, Fig. 3, nozzles controlled by a valve 24 are supplied with steam from the previous stage when extra power is required.