Installation comprising steam turbine modules with optimized efficiency

Abstract

An installation includes a high pressure steam turbine module, a medium pressure steam turbine module, and at least one low pressure steam turbine module, sealing devices being positioned between a rotating turbine shaft and corresponding casings of the various turbine modules, each of the modules include a main chamber in which the turbine is housed. The installation also includes a first collection chamber positioned in the casing of the high pressure module to collect the steam leaks leaving the high pressure module through its sealing device at a pressure greater than atmospheric pressure, and an injection chamber positioned in the casing of the low pressure module and connected by a first circuit to the first collection chamber such that the steam is transferred from the first collection chamber toward the injection chamber, and then toward the main chamber of the low pressure module through its sealing device.

What is claimed is: 
     
         1 . An installation comprising a high pressure steam turbine module, a medium pressure steam turbine module, and at least one low pressure steam turbine module, sealing devices being positioned between a rotating turbine shaft and corresponding casings of the various turbine modules, each of the modules comprising a main chamber in which a turbine is housed, the installation further comprising:
 a first collection chamber positioned in the casing of the high pressure module to collect steam leaks leaving said high pressure module through its sealing device at a pressure greater than atmospheric pressure, and   an injection chamber positioned in the casing of the low pressure module and connected by a first circuit to the first collection chamber such that the steam is transferred from the first collection chamber toward the injection chamber, and then toward the main chamber of the low pressure module through its sealing device.   
     
     
         2 . The installation as claimed in  claim 1 , wherein a second collection chamber is positioned in the casing of the medium pressure module so as to collect steam leaks leaving said medium pressure module through its sealing device at a pressure greater than atmospheric pressure, and transfer said leaks, via said first circuit, toward said injection chamber. 
     
     
         3 . The installation as claimed in  claim 1 , wherein a third collection chamber is positioned between the main chamber of the high pressure module and said first collection chamber in such a way that the steam leaks leaving said high pressure module through its sealing device at a pressure greater than atmospheric pressure are collected and said leaks are directed, via a conduit, toward the main chamber of the medium pressure module or toward an inlet of the main chamber of the low pressure module. 
     
     
         4 . The installation as claimed in  claim 3 , wherein the pressure in the third collection chamber is kept at a pressure level between a pressure in the main chamber of the high pressure module and a pressure in the first collection chamber. 
     
     
         5 . The installation as claimed  claim 1 , wherein each sealing device of the various steam turbine modules has a fourth collection chamber positioned in the casing of the module concerned, said fourth collection chamber having a pressure lower than atmospheric pressure, so as to collect not only the leaks of steam leaving said module through its sealing device but also air entering from outside the casing concerned. 
     
     
         6 . The installation as claimed in  claim 5 , wherein each fourth collection chamber is connected by a conduit to a second circuit at a pressure lower than atmospheric pressure. 
     
     
         7 . The installation as claimed in  claim 1 , wherein said first circuit has a pressure control device which keeps its pressure at a level above atmospheric pressure. 
     
     
         8 . The installation as claimed in  claim 1 , wherein each of said chambers communicates directly through at least one channel with a leak passage between said turbine shaft and the respective casings. 
     
     
         9 . The installation as claimed in  claim 8 , wherein each of said channels opens into said leak passage between two annular sealing gaskets.