Standard Unidirectional Groove Design Optional Bidirectional Groove Design Product Description Type 28 compressor dry-running gas seals have been the industry standard since the 197s for gas-handling turbomachinery. Utilizing John Crane's patented spiral groove pattern, these seals are non-contacting in operation. During dynamic operation, the mating ring/seat and primary ring/face maintain a sealing gap of approximately.2 in./5 microns, thereby eliminating wear These seals eliminate seal oil contamination and reduce maintenance costs and downtime 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 Design Features 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 Performance Capabilities Temperature: -22 F to 6 F/-14 C to 315 C Pressure: Speed: Shaft: Up to 6,5 psi(g)/45 bar(g) across single stage Up to 66 fps/2 m/s Up to 13.75"/35mm
Type 28AT Tandem Arrangement
Type 28XP Tandem Arrangement
Type 28XP-S Tandem Arrangement
Type 28EXP Tandem Arrangement Inlet for Filtered Seal (or Process) Gas SEAL (OR PROCESS) GAS Seal (Or Process) Gas Labyrinth Outlet for 1st Stage Leakage and Buffer Gas Interstage Labyrinth Inlet for Buffer Gas (Optional) Outlet for 2nd Stage Leakage and Separation Gas Separation Gas Supply Advanced Polymer Secondary Seal BEARING CAVITY Separation Seal - contact John Crane for options 1ST STAGE 2ND STAGE MATING RING PRIMARY RING MATING RING PRIMARY RING *Typical Application pressures up to 3,25 psi(g)/22 bar(g)
Typical Single Seal Arrangement and Seal Support System 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 EXTERNAL SUPPLY *Double Seal Arrangement where hazardous gas is not permissible to leak into atmosphere. JOHN CRANE GAS SEALS Typical Tandem Seal Arrangement and Seal Support System APPROVED APPROVED *Tandem Seal Arrangement for applications requiring a safety back-up seal. JOHN CRANE GAS SEALS
Size and Speed Effect on Leakage Conditions: Air, 1,2 psig/83 bar g Leakage (SCFM) 5 4 3 2 1 15 RPM 5 RPM 1 RPM 125 1 75 5 25 Leakage (sl/min) 2.187 3.187 4.187 5.187 6.125 7.125 8.125 9.125 1.125 (inch) 5 1 15 2 25 (mm) Seal Size Pressure, Temperature and Gas Effect on Leakage Conditions: 6.187-inch Diameter Seal, 14, rpm Leakage (SCFM) 5 4 3 2 1 125 1 75 5 25 Leakage (sl/min) Hydrogen, 1 F/38 C Methane, 1 F/38 C Air, 1 F/38 C Air, 3 F/15 C 2 4 6 8 1, 1,2 2 4 6 8 Pressure (psig) (bar g) Gas Seal Power Consumption Conditions: Air, 14 F/6 C Power (KW) 5 4 3 2 1 6. 5. 4. 3. 2. 1. Power (HP) 1 rpm; 1. psig/69 bar g 1 rpm; 1 psig/7 bar g 5 rpm; 1 psig/7 bar g 2.187 3.187 4.187 5.187 6.125 7.125 8.125 9.125 1.125 (inch) 5 1 15 2 25 (mm) Seal Size *This information should not be used for specification purposes. Contact DryGasSeals@johncrane.com for more information about exact application requirements.
North America United States of America Europe United Kingdom Latin America Brazil Middle East & Africa United Arab Emirates Asia Pacific Singapore Tel: 1-847-967-24 Fax: 1-847-967-3915 Tel: 44-1753-224 Fax: 44-1753-224224 Tel: 55-11-3371-25 Fax: 55-11-3371-2599 Tel: 971-481-278 Fax: 971-488-6283 Tel: 65-6518-18 Fax: 65-6518-183 If the products featured will be used in a potentially dangerous and/or hazardous process, your John Crane representative should be consulted prior to their selection and use. In the interest of continuous development, John Crane Companies reserve the right to alter designs and specifications without prior notice. It is dangerous to smoke while handling products made from PTFE. Old and new PTFE products must not be incinerated. ISO 91 and ISO141 Certified, details available on request. 215 John Crane Revised 1/15 www.johncrane.com TD-28AT/28XP/28XPS/28EXP