| 1 | O-Ring | Static flanges, hydraulic cylinders, pneumatic valves, pumps, and fittings | Static applications commonly up to about 200 bar; higher pressure requires back-up rings and suitable groove design | Approximately −50°C to +200°C, depending on elastomer | Air, water, hydraulic fluids, oils, fuels, and many chemicals when correctly compounded | Low cost, compact design, easy replacement, and wide material selection | Can extrude, twist, or wear under excessive pressure, rapid motion, poor lubrication, or incorrect sizing |
| 2 | PTFE Spring-Energized Seal | High-performance valves, pumps, rotary shafts, chemical processing equipment, and vacuum systems | Often suitable from vacuum service to approximately 300 bar, subject to design and anti-extrusion support | Approximately −70°C to +260°C for many PTFE designs | Aggressive chemicals, solvents, gases, steam, hydrocarbons, and clean process fluids | Very low friction, strong chemical resistance, broad temperature capability, and good shelf life | Higher cost; requires accurate installation, correct spring selection, and suitable surface finish |
| 3 | Hydraulic or Pneumatic Rod Seal | Cylinders, actuators, presses, injection-molding equipment, and mobile machinery | Commonly about 100–500 bar for hydraulic designs; pneumatic versions usually operate at much lower pressure | Approximately −40°C to +200°C, depending on compound and profile | Hydraulic oil, air, water-glycol fluids, and selected process fluids | Designed for reciprocating motion, effective fluid retention, and compact gland construction | Sensitive to rod damage, contamination, misalignment, extrusion gaps, and improper lubrication |
| 4 | Rotary Shaft Lip Seal | Gearboxes, electric motors, pumps, compressors, and rotating machinery | Generally low to moderate pressure, often up to approximately 0.5 bar without special support | Approximately −40°C to +200°C, depending on lip material and lubricant | Lubricating oils, greases, water, and selected low-pressure gases | Simple, economical, widely available, and effective at excluding dust and retaining lubricant | Not ideal for high pressure; lip wear increases with shaft runout, roughness, speed, and dry running |
| 5 | Mechanical Face Seal | Centrifugal pumps, mixers, agitators, compressors, and rotating process equipment | Commonly approximately 10–40 bar, depending on seal arrangement, speed, and fluid | Approximately −50°C to +250°C, depending on face and secondary-seal materials | Water, chemicals, hydrocarbons, slurry, steam, and process fluids with suitable face materials | Excellent containment for rotating shafts and much lower leakage than many packing arrangements | Requires accurate installation, controlled faces, proper cooling or lubrication, and protection from dry running |
| 6 | Metal Spiral-Wound Gasket | Pipe flanges, pressure vessels, heat exchangers, steam systems, and petrochemical equipment | Commonly suitable for high-pressure flange service, often above 100 bar when correctly selected and installed | Approximately −200°C to +500°C, depending on winding metal and filler | Steam, gases, hydrocarbons, oils, water, and many chemical process fluids | Handles high temperature and pressure; adaptable to flange imperfections and varied media | Usually single-use; requires correct bolt load, flange alignment, compression control, and surface condition |
| 7 | Braided Compression Packing | Valve stems, pump shafts, mixers, and equipment where adjustable sealing is acceptable | Typically about 10–100 bar, depending on construction, shaft speed, and service conditions | Approximately −100°C to +500°C, depending on fiber and lubricant | Water, steam, oils, chemicals, and abrasive fluids with compatible packing materials | Adjustable, repairable in place, tolerant of some shaft irregularity, and suitable for large equipment | Normally permits controlled leakage; excessive tightening can create heat, wear, and shaft damage |
| 8 | Labyrinth Seal | High-speed bearings, turbines, compressors, gearboxes, and rotating dry-gas equipment | Best for low differential pressure; pressure capability depends strongly on stages, clearances, and purge design | Approximately −50°C to +500°C, depending mainly on material and equipment design | Air, dry gases, lubricating oil environments, and applications requiring non-contact sealing | Non-contact operation, minimal friction, high-speed capability, and long service life when clearances are maintained | Not a complete zero-leakage barrier; sensitive to pressure reversal, contamination, shaft movement, and clearance changes |
| 9 | Metal C-Ring or E-Ring Seal | Vacuum chambers, aerospace-style equipment, high-temperature vessels, and precision flanges | From high vacuum to high-pressure service, subject to cross-section, plating, groove design, and flange loading | Approximately −200°C to +800°C, depending on metal alloy and coating | High-purity gases, vacuum, steam, hydrocarbons, and demanding chemical or thermal environments | Very low gas permeability, strong temperature resistance, and long-term stability in severe service | High cost; requires rigid, accurately machined sealing surfaces and carefully controlled compression |
| 10 | Inflatable Seal | Large doors, vacuum chambers, cleanrooms, containment systems, and equipment with variable gaps | Usually low differential process pressure; the inflation pressure is commonly around 1–3 bar above ambient | Approximately −40°C to +200°C, depending on elastomer and reinforcement | Air, gases, dust, water, and selected chemicals with compatible rubber compounds | Compensates for uneven or changing gaps, retracts when uninflated, and provides a broad contact area | Requires a reliable inflation system; vulnerable to puncture, excessive gap movement, and incompatible media |
