2. MECHANICAL SEALS

3. 2 I - TECHNICAL ASPECTS OF MECHANICAL SEALS

4. 3 2- MECHANICAL SEALS PUMPING SEALS 1- PACKING SEALS

5. 4 1- Packing seals

6. 5 Equipment PACKING WITHOUT SLEEVE Wear is directly on shaft GLAND THROAT BUSH FOLLOWER PACKING LANTERN RING

7. 6 Equipment GLAND THROAT BUSH FOLLOWER PACKING LANTERN RING SLEEEVE PACKING WITH SLEEVE PACKING WITH SLEEVE * Wear is on the sleeve

8. 7 Horizontal Surface wear Shaft wear Equipment Now it essential to find a solution to avoid shaft wear, Such as finding another surface of another parts to be worn but easy and cheap to be replaced, It is the MECHANICAL SEAL

9. 8 2- Mechanical Seals

10. 9 Equipment Vertical surface wear Scarifying elements

11. 10 Equipment Rotary Elements 1- Carbon ring 2- Snap Ring 3- “O” Rings 4- Springs 5- Sleeve Stationary Element Tungsten Carbide ring Or Silicon Carbide ring Single mechanical seal

12. 11 SINGLE IMPELLER PUMP MECHANICAL SEAL

13. 12 MULTI STAGE PUMP DRIVE END NON-DRIVE END IN-BETWEEN TWO BEARINGS IMPELLER IN-BETWEEN TWO BEARINGS IMPELLER MECHANICAL SEALS

14. 13 Mechanical seal and bearings arrangement oil Equipment

15. 14

16. 15 Mechanical seal Mechanical seal Thrust Bearing

17. 16 Bellow Type Mechanical Seal

18. 17

19. 18 Bellow Mechanical Seal BELLOW Rotary ring Stationary ring

20. 19 Double Mechanical seal Bellow type BELLOW

21. 20 Bellows –Uniform uniform stress distribution Bellows – 45° tilt for enhanced fatigue strength –Three sweep radius

22. 21 Bellows Benefits For higher pressure Generally have light spring loads –Less heat –Low power consumption –Longer seal life Pressure balanced by design For high temperature applications >260°C/500°F

23. 22 Split Type Mechanical Seal

24. 23 Split Seals

25. 24 Cartridge Split Seal

26. 25 Plant Operations Rotating equipment maintenance costs can be about 20 % of the total maintenance budget. Rotating equipment is taken out of service 70% of the time due to a leaking Mechanical seal.

27. 26 Split Seals –Reduced man hours / improve productivity Benefits Over Mechanical Seals : –No Dismantling of Equipment –Fast maintenance / high equipment availability –Reduced complexity

28. 27 Time Production Maintenance Budget Manpower Split Seals merits

29. 28 Rival Sealing Technology Split Seals -All the advantages of mechanical seals. -Plus, they are easier and quicker to install Mechanical seals Are the dominant technology in many industries.

30. 29 Cost Benefit Analysis

31. 30 Split Seals Target Applications – Shaft size greater than 3 ” / 76 mm – Vertical pumps – Side entry agitators Limitations of Split Seals –Not recommended for applications where emissions will be a dangerous to the environment or humans

32. 31 Hydraulic Balance

33. 32 Balanced mechanical seal Carbon ringStationary Product +Springs Contact face pressure > STRESS S PRESSURE P

34. 33 Unbalanced mechanical seal StationaryCarbon ring Product + Springs Contact face pressure < PRESSURE P STRESS S

35. 34 FACE AND SEAT AREA EQUAL 100% BALANCE F = P * A F = S * A P * A = S * A P = S A = Contacted Surface area S = Contacted Surface stress P = Product + Spring pressure F = Acting force S P = 100 % A P Carbon ring A S Stationary ring

36. 35 HYDRAULIC BALANCE OF SEALS 50 % BALANCE F = P * A 1 F = S * A A S P * A 1 = S * A S P = 50 % 0.5 AA1A1 P P P = S P A1A1 A A = Contacted Surface area A 1 = Projected area of P S = Contacted Surface stress P = Product + Spring pressure F = Acting force

37. 36 HYDRAULIC BALANCE OF SEALS 75 % BALANCE F = P * A 1 F = S * A A S P * A 1 = S * A 0.75 AA1A1 P S P = 75 % = S P A1A1 A A = Contacted Surface area A 1 = Projected area of P S = Contacted Surface stress P = Product + Spring pressure F = Acting force

38. 37 OPTIMUM HYDRAULIC BALANCE Above 85 % ------------- WEAR Below 65 % ------------- LEAK Optimum Balance 75 % for medium pressure seals. Balance percentage is a compromise :

39. 38 P S A 1 ( projected area of P) (product + spring pressure) (contacted surface stress) = A ( contacted surface area) 120 cm2 230 cm2 = Mechanical seal has the following data: A = contacted surface area = 230 cm2 A 1 = ( projected area of P) = 120 cm2 Calculate the hydraulic balance Percentage SOLUTION = 0.52 *100 = 52 % Hydraulic balance % is less than 65 % This Mechanical is prone to leak Hydraulic balance % is less than 65 % This Mechanical is prone to leak

40. 39 P S A 1 ( projected area of P) (product + spring pressure) (contacted surface stress) = A ( contacted surface area) 180 cm2 200 cm2 = Mechanical seal has the following data: A = contacted surface area = 200 cm2 A 1 = ( projected area of P) = 180 cm2 Calculate the hydraulic balance Percentage SOLUTION = 0.9 *100 = 90 % Hydraulic balance % is more than 85 % This Mechanical is prone to wear Hydraulic balance % is more than 85 % This Mechanical is prone to wear

41. 40 P S A 1 ( projected area of P) (product + spring pressure) (contacted surface stress) = A ( contacted surface area) 24 cm2 30 cm2 = Mechanical seal has the following data: A = contacted surface area = 30 cm2 A 1 = ( projected area of P) = 24 cm2 Calculate the hydraulic balance Percentage SOLUTION = 0.80 *100 = 80 % This Mechanical is hydraulic balanced as it is in between 65 % and 85 % This Mechanical is hydraulic balanced as it is in between 65 % and 85 %

42. 41 Hydraulic Balance - Benefits Increased pressure range for the seal –this simple modification allows much higher pressures to be sealed. Reduced heat generation –ideal for unstable and low SG fluids –less heat to be dissipated - less cooling required Reduced wear rate –longer life Reduced power required to drive the seal –lower running costs

43. 42 II-OPTIONAL FEATURES

44. 43 Quenching Circulation Flushing Ancillaries

45. 44 Quenching “ IN " Plant Steam 0.1 - 0. 2 bar To Drain “ OUT " 1. Block Valve 2. Pressure Gauge 3. Check Valve PI ATM 3 PREVENT PRODUCT TO BUILD UP PRESSURE ON ATMS. SIDE PREVENT PRODUCT TO BUILD UP PRESSURE ON ATMS. SIDE WATER L.P. STEAM OR

46. 45 Flushing Quenching ATMOSPHERE

47. 46 Flushing Flushing liquid : *Filtered Product *Solvent *Water *Compatible liquid BUT NOT Gas Pump product Steam Flushing liquid : *Filtered Product *Solvent *Water *Compatible liquid BUT NOT Gas Pump product Steam Flushing Liquid Pressure = S tuffing Box Pressure + 1 bar min Flushing Liquid Pressure = S tuffing Box Pressure + 1 bar min T1 P1 Flushing Liquid

48. 47 Quench fluid Flush fluid

49. 48 Quench fluid Flush fluid

50. 49 Quench –low pressure (0.5 bar g) –low flow (0.5 litres/minute) –external to main seal –no contamination –no dilution Quench –low pressure (0.5 bar g) –low flow (0.5 litres/minute) –external to main seal –no contamination –no dilution Flush –high pressure ( > 1.0 bar above seal pressure) –injected into seal chamber –cools pumped product –dilutes pumped product. Flush –high pressure ( > 1.0 bar above seal pressure) –injected into seal chamber –cools pumped product –dilutes pumped product.

51. 50 Circulation CYCLONE

52. 51 Heat control / removal API Plan 21

53. 52 System must be above, and within 3 metres of pump. Fluid circulates by thermosyphon. May need small pump or pumping scroll to assist flow. Thermosyphon Cooling

54. 53 Circulating liquid Barrier fluid QuenchfluidQuenchfluid

55. 54 Multiple Seals Other arrangements - Concentric; Face-to-Face; etc. Two common arrangements - Tandem - low pressure barrier fluid - Inboard seal lubricated by product - Double ( Back-to-Back ) - Pressurised barrier fluid - Inboard seal lubricated by barrier fluid

56. 55 Tandem Seal Clean barrier fluid lubricates this seal Outboard Seal Barrier fluid is at low (atmospheric) pressure. Use API Plan 52 Inboard Seal Product fluid lubricates this seal

57. 56 Double seals : Back-to-back Pressurised barrier fluid is circulated barrier fluid lubricates both sets of seal faces. Use API Plan 53

58. 57 Double seals : Face-to-face Stationary seals Rotating Mating Ring

59. 58 Barrier fluid Circulation Product Circulation Equipment Tandem Seal

60. 59 Tandem Seal Barrier fluid Circulation Product Circulation Equipment PpPp Barrier fluid Circulation Barrier fluid Circulation P BF = 1 bar max P BF

61. 60 Barrier fluid Circulation Product Circulation Flushing Liquid Equipment Double Seal

62. 61 P BF Barrier fluid Circulation Product Circulation Flushing Liquid Double Seal Barrier fluid Circulation Barrier fluid Circulation (Min) P BF = 1.1 P p Not less than ( 2+ P p ) bar

63. 62 BALANCING DRUM P 4 – P 0 P4P4 P0P0 P1P1 P2P2 P3P3 P4P4 P4P4 Balancing Pressure Room Balancing Pressure Room BALANCING LINE P0P0 P0P0

64. 63 Barrier fluid Type Temperature Range Barrier fluid - 120 to - 90 Propanol 0 C - 90 to - 30 Methanol 0 C -30 to + 20 Kerosene or Hydraulic oil 0 C + 20 to + 200 L.G.O. or H.G.O. 0 C

65. 64 Coolers for circulating liquids Flow controllers for circulating liquids ( adjustable orifices ) Cyclones for circulating liquids Strainers for circulating liquids Magnetic filters for circulating liquids Ancillaries

66. 65 MULTI STAGE COMPRESSOR