1. GE Power Systems
Oil & Gas
STEAM SEALING CONDENSERS CM&Us
CM&Us
STEAMTURBINESSTEAMTURBINES
• eliminate lube oil contamination due to condensing
water migration into the oil from the seals and achieve
longer operational life before oil change.
SELECTION AND OPTIONS
Two options are available to the customer.
1) use of a steam driven ejector to obtain the needed vacuum
2) use of a vacuum pump driven by an electric motor.
In the first case the system must supply the necessary
steam conditions (pressure, temperatures and flow) for the
ejector.
The size of the Gland exchanger (figure 3) is selected
based on the type of steam turbine because seal steam
flow has already been calculated for each model.
SCOPE OF SUPPLY
Complete preassembled skid (for figure 2a version) consist-
ing of:
• Steam ejector
• Gland condenser exchanger
• Gland condenser supports
• Condensate tank (50 lt) capacity
• Motive steam inlet Y filter
• Motive steam regulating valve
• Motive steam manometer
INTRODUCTION
The Gland Sealing and Leak-Off System is currently
required on all new steam turbines by API 612 (American
Petroleum Institute) fourth edition June 1995 to increase
the quality of installations. A complete preassembled kit to
update steam turbines designed in accordance with the
previous API version and not equiped with this system is
described here.
TECHNICAL DESCRIPTION
The preassembled kit use a vacuum generated by a
Venturi tube fied by medium or low pressure steam usually
available as surplus from other auxiliaries system. It is pos-
sible to use a vacuum pump powered by an electric motor
to obtain the required vacuum if prefered by customer. The
steam coming from steam turbine extremity seals is diverted
into an under vacuum heat exchanger sized in accordance
with ASME VIII-1 or to meet special requirements of the
final installation country on customer request. Condensing
steam is collected in a suitable tank instead of being
exhausted from the machine as polluted steam. The skid is
completed whit manometers, inlet steam Y filter and a steam
regulating valve before the ejector. A pressure switch is also
provided for customer control room interconnection for
detection of loss of vacuum.
Steam turbine running without Gland Condenser
Figure 1 shows how steam coming from seals can migrate
and condense in the bearing lube oil system causing degra-
dation of lube oil characteristics. Pollution due to the release
of toxic vapours containing additives from the machine is
also shown.
Steam turbine running with Gland Seal System
Figures 2a and b present two configurations of the Gland
Sealing System (use of a steam ejector or refrigerated vac-
uum pump and eletric motor). The figures show how water
migration to the lube oil system is eliminated and contami-
nation of the lube oil by steam leakage is avoided.
APPLICATION
The system can be used on all back pressure and con-
densing steam turbines including those of other manufac-
turers and can be installed near the turbine skid.
BENEFITS
The Gland And Vacuum Seal System is able to:
• eliminate steam vapours around the machine which
are usually toxic due to additives found in the machine
• reduce the humidity around the machine resulting in
safer operation of all electric devices installed in the
area
CM&Us TU/VA05-9/2002
