Catalogs >
John Crane >
Type 28AT_2012

Type 28AT_2012
6Pages

Catalog excerpts

Dry-Running, Non-Contacting Gas Seals Standard Unidirectional Groove Design Optional Bidirectional Groove Design Product Description Type 28 compressor dry-running gas seals have been the industry standard since the 1970s for gas-handling turbomachinery. Utilizing John Crane's patented spiral groove pattern, these seals are non-contacting in operation. I Shrouded mating ring prevents secondary damage in the event of a mating ring fracture Low-level leakage can be vented to a safe area, used as fuel to drive equipment, or returned to process via a low-pressure ejector During dynamic operation, the mating ring/seat and primary ring/face maintain a sealing gap of approximately 0.0002 in./5 microns, thereby eliminating wear These seals eliminate seal oil contamination and reduce maintenance costs and downtime Performance Capabilities Single, double opposed, and tandem cartridge seals are capable of handling a wide variety of gas sealing applications in the gas collection/transmission, refining, chemical and petrochemical processing industries Up to 6,500 psig/450 bar g across single stage *Contact DryGasSeals@johncrane.com for more information about exact application requirements. TYPE 28 Compressor Seals

Open the catalog to page 1

Seal (or Process) Gas Labyrinth Outlet for 1st STAGE Leakage and Buffer Gas PRIMARY RING MATING RING Inlet for Filtered Seal (or Process) Gas Type 28AT Tandem Arrangement Inlet for Buffer Gas (Optional) Outlet for 2nd STAGE Leakage and Separation Gas Separation Seal contact John Crane for options BEARING CAVITY O-Ring Secondary Seal *Typical Application pressures up to 1,800 psig/125 bar g PRIMARY RING 2nd STAGE MATING RING Interstage Labyrinth Dry-Running, Non-Contacting Gas Seals TYPE 28 Compressor Seals

Open the catalog to page 2

Seal (or Process) Gas Labyrinth Inlet for Filtered Seal (or Process) Gas Outlet for 1st STAGE Leakage and Buffer Gas MATING RING PRIMARY RING Type 28XP Tandem Arrangement Inlet for Buffer Gas (Optional) MATING RING Outlet for 2nd STAGE Leakage and Separation Gas Polymer Secondary Seal Separation Seal - contact John Crane for options BEARING CAVITY *Typical Application pressures up to 3,000 psig/200 bar g PRIMARY RING Interstage Labyrinth Dry-Running, Non-Contacting Gas Seals TYPE 28 Compressor Seals

Open the catalog to page 3

Seal (or Process) Gas Labyrinth Outlet for 1st STAGE Leakage and Buffer Gas PRIMARY RING MATING RING Inlet for Filtered Seal (or Process) Gas Type 28EXP Tandem Arrangement Inlet for Buffer Gas (Optional) MATING RING Separation Seal - contact John Crane for options BEARING CAVITY Advanced Polymer Secondary Seal Outlet for 2nd STAGE Separation Gas Leakage and Supply Separation Gas *Typical Application pressures up to 6,500 psig/450 bar g PRIMARY RING Interstage Labyrinth Dry-Running, Non-Contacting Gas Seals TYPE 28 Compressor Seals

Open the catalog to page 4

TYPE 28 Compressor Seals Dry-Running, Non-Contacting Gas Seals Size and Speed Effect on Leakage Conditions: Air, 1,200 psig/83 bar g 5 Leakage (SCFM) Leakage (sl/min) Seal Size Pressure, Temperature and Gas Effect on Leakage Conditions: 6.187-inch Diameter Seal, 14,000 rpm 5 125 100 3 Leakage (sl/min) Leakage (SCFM) Gas Seal Power Consumption Conditions: Air, 140°F/60°C 5 Seal Size *This information should not be used for specification purposes. Contact DryGasSeals@johncrane.com for more information about exact application requirements.

Open the catalog to page 5

TYPE 28 Compressor Seals Dry-Running, Non-Contacting Gas Seals Typical Single Seal Arrangement and Seal Support System VENT JOHN CRANE GAS SEALS *Single Seal Arrangement for applications not requiring a safety back-up seal. Typical Double Opposed Seal Arrangement and Seal Support System VENT EXTERNAL SUPPLY JOHN CRANE GAS SEALS *Double Seal Arrangement where hazardous gas is not permissible to leak into atmosphere. Typical Tandem Seal Arrangement and Seal Support System VENT APPROVED VENT APPROVED VENT JOHN CRANE GAS SEALS *Tandem Seal Arrangement for applications requiring a safety back-up...

Open the catalog to page 6