The extraction condensing turbines are used when a constant pressure steam flow has to be extracted for process purposes. The constructional characteristics of these turbines are very similar to condensing
turbines From the second admission valve chest it is possible to inject low pressure steam, available in the plant to supply the power required by the plant.
These turbines are typically used for co-generation where the turbine meets both the power and steam demand of the process plant. In these type of turbines the power generated can be maintained more or less at a steady level despite variation in process steam demands. In some cases it may be necessary to have both bleed and controlled extraction steams from the condensing turbine. These turbines are of bleed cum extraction condensing type.