Gland vent condensers play an essential role in main and auxiliary turbine systems by supporting effective shaft sealing and maintaining turbine efficiency. In steam turbines, the shaft must exit the casing to connect with driven equipment such as reduction gears, pumps and other rotating machinery. The gland sealing system helps seal the turbine at these shaft exit points, effectively keeping air out and steam in.
The primary purpose of a gland seal system is to prevent atmospheric air from leaking into the turbine casing while also preventing steam from escaping into the atmosphere. By maintaining this controlled sealing environment, the system helps protect condenser vacuum, improve turbine efficiency and support stable plant operation.
The gland sealing system supplies low-pressure steam to the turbine gland through the final sets of labyrinth packing. This assists the labyrinth seals in preventing air ingress into the turbine, which could otherwise reduce or destroy the vacuum in the associated condenser. Any excess gland seal pressure is removed through the gland seal unloader.
During operation, small amounts of steam may escape from the seals. To manage this, a gland exhaust system is provided. This system consists of low-pressure piping connected to the gland area between the outer sets of labyrinth packing, where it collects leaked steam and prevents it from escaping into the atmosphere. The collected steam is then directed to a condenser for recovery and reuse within the steam plant.
Steam leakage from the gland seal area of the shaft packing, steam leak-off from steam chest lift rods and steam leak-off from the trip throttle valve are drawn into the gland exhaust system and routed to the air ejector condenser. Within the condenser, the steam is condensed, while air and non-condensable gases are discharged to the atmosphere through a gland exhaust fan or ejector, which maintains a slight vacuum on the auxiliary air ejector condenser.
Most steam turbines use a shaft sealing system with carbon rings to isolate the rotor assemblies at both ends. Steam is injected into the sealing system to prevent air in-leakage into the turbine. If not properly controlled, this leakage can reduce turbine efficiency and flow into the downstream condenser, further affecting overall system performance. The gland steam must therefore be removed efficiently by an ejector or exhaust fan to prevent it from flowing back into the turbine.
New Field offers advanced technology and proven engineering capability in the basic and detailed design of gland steam condensers for thermoelectric and nuclear power plant applications. Our design approach includes vibration analysis, stress analysis and fatigue analysis to enhance reliability, improve operational confidence and ensure long-term equipment performance.
With 54 years of experience, New Field has extensive expertise in major international codes and standards, including ASME and TEMA, as well as regional regulatory requirements such as PED, DOSH and CSA. This enables us to deliver gland vent condenser solutions that meet demanding project specifications, international compliance requirements and the operational expectations of power generation clients worldwide.
