MIL-HDBK-1003/7
Polluted Water. Coated carbon steel water boxes with cathodic protection is
7.3.5.3
the recommended choice for use with titanium or the new austenitic and ferritic
stainless steel tubes.
Exhaust Neck. The connection piece extending from the turbine exhaust flange
7.3.6
to the main body of the condenser and often referred to as the condenser neck is made of
the same material as the condenser shell.
7.3.7
Expansion Joints
7.3.7.1
Exhaust Neck. For bottom supported condensers, an expansion joint made of
copper, stainless steel, or rubber is located between the turbine exhaust flange and the
main body of the condenser, either as a part of the exhaust neck of the condenser or
separate component. Corrosion of copper joints has caused the use of this material to
be essentially discontinued. The use of stainless steel is satisfactory but expensive.
The majority of all condensers are now furnished with a rubber (dogbone type) expansion
joint. The rubber dogbone type is preferred because it can more easily be replaced as
compared to a stainless steel joint.
Shell. Depending upon the type of tube to tubesheet joining, there can be and
7.3.7.2
usually is a difference in expansion between the shell and tubes during operation.
Suitable means must be incorporated in the design of the condenser to provide for this
differential expansion. Both flexing steel plate and U-bend type have been used;
however, the majority of condensers are furnished with a steel U-bend type that is
usually located adjacent to one of the tube sheets.
7.4
Condenser Support
7.4.1
Bottom Support. Bottom support is the simplest method and consists of
extension piece, or condenser neck as it is commonly called is attached to the turbine
exhaust flange by bolting or welding and contains an expansion joint of stainless steel,
copper, or rubber.
Spring Support. The condenser is bolted directly to the turbine exhaust
7.4.2
flange and supported at the bottom feet by springs to allow for expansion. This avoids
the use of an expansion joint in the condenser neck. However, all piping connected to
the condenser for auxiliaries must be provided with expansion joints to permit free
movement of the condenser. This method is seldom used.
Rigid Support. The condenser is bolted to and supported from the turbine
7.4.3
exhaust.
The center of gravity of the condenser must be centered on the turbine
exhaust.
As with the spring support method, all auxiliary piping must be provided with
expansion
joints. The use of this method is restricted to small turbine generator
units.
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