GE Power SystemsOil & Gas

STEAM SEALING CONDENSERS CM&UsCM&Us

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• eliminate lube oil contamination due to condensingwater migration into the oil from the seals and achievelonger operational life before oil change.

SELECTION AND OPTIONSTwo options are available to the customer.1) use of a steam driven ejector to obtain the needed vacuum2) use of a vacuum pump driven by an electric motor.

In the first case the system must supply the necessarysteam conditions (pressure, temperatures and flow) for theejector.

The size of the Gland exchanger (figure 3) is selectedbased on the type of steam turbine because seal steamflow has already been calculated for each model.

SCOPE OF SUPPLYComplete 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

INTRODUCTIONThe Gland Sealing and Leak-Off System is currentlyrequired on all new steam turbines by API 612 (AmericanPetroleum Institute) fourth edition June 1995 to increasethe quality of installations. A complete preassembled kit toupdate steam turbines designed in accordance with theprevious API version and not equiped with this system isdescribed here.

TECHNICAL DESCRIPTIONThe preassembled kit use a vacuum generated by aVenturi tube fied by medium or low pressure steam usuallyavailable as surplus from other auxiliaries system. It is pos-sible to use a vacuum pump powered by an electric motorto obtain the required vacuum if prefered by customer. Thesteam coming from steam turbine extremity seals is divertedinto an under vacuum heat exchanger sized in accordancewith ASME VIII-1 or to meet special requirements of thefinal installation country on customer request. Condensingsteam is collected in a suitable tank instead of beingexhausted from the machine as polluted steam. The skid iscompleted whit manometers, inlet steam Y filter and a steamregulating valve before the ejector. A pressure switch is alsoprovided for customer control room interconnection fordetection of loss of vacuum.

Steam turbine running without Gland Condenser Figure 1 shows how steam coming from seals can migrateand condense in the bearing lube oil system causing degra-dation of lube oil characteristics. Pollution due to the releaseof toxic vapours containing additives from the machine isalso shown.

Steam turbine running with Gland Seal System Figures 2a and b present two configurations of the GlandSealing System (use of a steam ejector or refrigerated vac-uum pump and eletric motor). The figures show how watermigration to the lube oil system is eliminated and contami-nation of the lube oil by steam leakage is avoided.

APPLICATIONThe 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.

BENEFITSThe 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 thearea

CM&Us TU/VA05-9/2002

Nuovo Pignone S.p.A.

via F. Matteucci, 2 - 50127 Florence (Italy) Tel. +39-055-423-211- Fax +39-055-423-2800E-mail: info.service@np.ge.comwww.gepower.com/geoilandgas

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• Coupling• Coupling guard• Gland condenser exchanger• Gland condenser supports• Condensate tank (50 lt) capacity• Vacuum manometer• Vacuum pressure switch• Vent and drain valves on water side of exchanger• Drain valve on condensate tank

• Vacuum manometer• Vacuum pressure switch• Vent and drain valves on water side of exchanger• Drain valve on condensate tank

Complete preassembled skid (for fig 2b version) consisting of:• Vacuum pump with self cooling• Electric motor with terminal strip

Vent

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STEAM SEALING CONDENSERS