Turbo machine with an axial dry gas seal

A turbo machine, such as a gas turbine or a turbo compressor, having a barrier gas at high pressure, a high-speed rotating shaft in a machine housing, and including an axial shaft seal arrangement in said housing wherein said shaft seal arrangement comprises:

• at least one dry gas seal(s), which consists of a rotating sealing body rotating with said shaft and of a non-rotating sliding ring in said housing for permitting planned limited leakage of said barrier gas through a sealing gap between said rotating sealing body and said non-rotating, axially-sliding ring to a low pressure area;
• a further restriction being located between said housing and said shaft, said restriction taking the form of a circular orifice surrounding said shaft with a small clearance, but not touching said shaft, whereby said further restriction is located downstream of said dry gas seal in said low pressure area and define a chamber towards said dry gas seal, where, via a reduced pressure level, said pressure increases with increasing leakage through said dry gas seal;
• and
• a pressure inspection device, said pressure inspection device being connected to said chamber for detecting changes of said planned limited leakage by means of different pressure indications and for providing a signal when a predetermined pressure is exceeded.