TRI designs, manufactures, and supplies upgraded hydrogen seal ring assemblies for GE Generators of all sizes and speeds. Major advantages are that they provide improved sealing and lower hydrogen gas usage which means that higher gas pressures can be used. This provides improved cooling of the stator and rotor, which in turn permits higher MW generation, higher MVAR operation, and higher reliability and availability.
The critical features and upgrades include:
- The upper outer housing is removable, permitting direct access to the garter spring and the hydrogen seal rings. This makes seal ring and spring installation very easy and reliable.
- TRI seal rings are made of heat treated alloy steel with Babbitt lined bore. Because the steel seal rings and the generator rotors are very similar alloy steels, the diametral clearance that is set when cold remains relatively constant for all operating temperature conditions. TRI specifies clearances that are larger than the clearances for Bronze rings because the clearances for bronze rings get measurably larger with increasing temperature and the clearances for steel rings remain relatively constant. The objective is for the steel ring clearances to match the bronze ring clearances at normal operating temperatures.
- The original GE bronze seal rings are made in quarter sections. The butt joints where the sections of the bronze rings meet do not always seal as intended and leak oil and hydrogen gas. Many of these seals are still in service and are substantial candidates for replacement.
- TRI's steel and Babbitt seal rings are made in halves and the joints include tight dowel pins and separate screws. There is no clearance within this joint, making a very tightly sealed joint with no losses. Another consequence is that there is NO STEP at the joint, so the oil film is continuous across the joint. A consequence of a step that can easily occur in the GE steel ring design is that it can scrape the oil film off the journal which causes the seal ring to contact the journal resulting in overheated and wiped seals.
- Under high vibration conditions of the generator rotor, bronze seals sometimes separate at the joints causing severe leakage. This cannot happen with steel rings because they have screws and dowel pins to hold them together tightly at the joints.
- Each seal housing contains an insulating ring made of NEMA Grade G-10 Industrial Laminate to mate to the generator frame. The screws that retain the seal housing to the frame have a wound epoxy-fiberglass insulation that duplicates the G-10 material, along with insulating and hardened steel washers. Removable jack screws to align the seal housing to the journal are included.
- TRI can also provide inner oil deflectors that are steel backed and have numerous aluminum strips to minimize oil getting into the generator itself. These TRI Inner Oil Deflectors are insulated and have alignment screws for easy alignment to the rotor.