1. Labyrinth seal into two halves

2. Labyrinth Seal

3. Labyrinth Seal

4. Labyrinth seal consist of a series of circumferential
Labyrinth seals
Labyrinth seal consist of a series of circumferential
strips of soft metal extending from the shaft housing
(or the rotor housing).
Labyrinth seals are used in gas turbines in two different areas:
In the turbine section, to perform sealing around the rotor.
Its job is to minimize escape of gases from high pressure
area to low pressure area.
In the bearing housing, to minimize escape of
pressurised air to outside.
If the pressurized air escapes, the lube oil will escape too.

5. RADIAL TILTING PAD
BEARING
CASING
SHAFT
Radial
Load

6. Oil Wedge
Friction Effect
Oil Wedge Effect
Shaft

7. Oil Wedge Oil adhere to the rotating shaft Oil squeeze between
shaft and bearing pad
forming a solid
oil wedge
Oil adhere to
the rotating shaft

8. RADIAL TILTING PAD BEARING
SHAFT
PIN
OIL
CASING

9. RADIAL MAGNITIC BEARING

10. THRUST MAGNITIC BEARING

12. Gas Compressors Sealing System

13. ** Centrifugal Compressor Operation
SCRUBBER
ANTI-SURGE
VALVE
SCRUBBER
ANTI-SURGE
VALVE
SCRUBBER
ANTI-SURGE
VALVE
SCRUBBER
COOLER
COOLER
COOLER
1St Stage
2 Nd Stage
3 Rd Stage

14. General aspects
1- A Complete spare balanced rotor to be ideally stored in W.H
2- Compressor will be equipped with a complete surge control system.
3- It is advisable to use dry gas seal system instead of wet seal one. 14

15. Compressor Sealing System
1- Wet seal system
( USING OIL FOR SEALING THE GAS )
2- Dry Gas Seal
(COMPRESSOR GAS USED FOR SEALING THE GAS ) 15 15

16. 1- Wet seal System 16

17. Oil sealing system CLEAN SEAL OIL GAS TO FLARE CONTAMINATED
COMPRESSOR GAS
GAS TO FLARE
CLEAN
OIL TO
RESERVOIR
Drain pot
CONTAMINATED
OIL TO DISPOSAL
CLEAN
SEAL OIL 17

18. Gas to flare Wet (Oil) sealing system Contaminated Oil to disposal
Compressor rotor
Oil Mech. seal
Heater
Oil Tank
Gas to flare
FILTERS
Drain pot
Drain pot
Contaminated
Oil to disposal
OIL PUMPS 18

19. Oil sealing system Opened Gas to flare Oil to disposal 19 REFRENCE
LINE
SEAL OIL
HEAD TANK
Opened
Gas to flare
FILTERS
Drain
pot
Drain pot
Oil to disposal
OIL PUMPS
SEAL OIL COOLER 19
SEAL OIL TANK
HEATER

20. In case of power failure
REFRENCE
LINE
SEAL OIL
HEAD TANK
Closed
Gas to flare
FILTERS
Drain
pot
Drain pot
Oil to disposal
OIL PUMPS
SEAL OIL COOLER 20
SEAL OIL TANK
HEATER

21. Typical Seal Oil Trap ( Drain pot )21

22. LUBE OIL SYSTEM To Main Lube Oil Reservoir Lube Oil Drain Header
From Lube Oil Control Valve
7000 mm Above
Machine C/L
Rundown Tank
Lube Supply Oil Header
To Lube Oil Reservoir
LUBE OIL
SYSTEM
Electric Motor
G box
Lube Oil Drain Header
To Main Lube Oil Reservoir
Centrifugal
Compressor
LSC
HSC 22

23. In case of Wet seal system
THE RECOMMENDED SEAL OIL CONSUMPTION IS ABOUT
40 LITRES PER DAY.
IF THE SEAL IS DETERIORATED, THE SEAL OIL
CONSUMPTION WILL INCREASE TO BE MORE THAN
500 LITRES PER DAY. 23

24. 2- Dry gas seal system 24

25. NO WEAR DURING ROTATION
Rotating Ring
Stationary Ring
Rotating Ring
Stationary Ring
Wet Seal
( contact faces )
Dry gas Seal
( Non contact faces ) 25

26. NO WEAR DURING ROTATION
ROTATING ELEMENT
STATIONARY ELEMENT
GAP 26

27. History of Dry Gas Seals
1925 to 1964 spiral groove bearing technology
1968 Curved face seal with spiral grooves
1970 Light duty gas seal (Type 28LD) developed for motors
1988 Light duty gas seal (Type T28) for gas compressors
1992 Introduction of a double gas seal for process pumps
1992 Big bore seal chambers
1995 Standard bore seal chambers
1995 Introduction of a metal bellows gas seal
1997 Introduction of High Pressure compressors/pumps seal
1997 Introduction of Slow Speed mixer seal 27

28. Spiral Groove
Rotary Carbon Rings 28

29. Spiral Groove Sealing Surface
Rotating Mating Ring 29

30. Spiral grooves
Carbon
Ring
Tungsten 30

31. ( Principle of operation)
Rotating or stationary ring
Rotating or stationary
ring
GAS
Spiral grooves
Sealing dam
Groove
diameter
Tungsten carbide ring
BEFORE ROTATION 31

32. GAS Spiral grooves Sealing dam AFTER ROTATION
Rotating or stationary ring
Rotating or stationary
ring
Spiral grooves
Sealing dam
Groove
diameter
AFTER ROTATION 32

33. Gas Rushes into
spiral grooves
Gas
Gas
Gas
Gas
Gas
Gas 33

34. Spiral Groove Operation
Gas Enters And is Induced Towards
the Center
Gas is Compressed and Pressure Increases to Set Sealing Gap
Sealing Dam
Rotational direction
Gas pressure rises along spiral grooves
Cushion of gas
separates sealing faces
Contact eliminated 34

35. HOW DRY SEAL WORKS 35

36. Filtered process gas inlet buffer gas to separation barrier
Supply of
buffer gas
buffer gas to
separation barrier
process gas
+ buffer gas
TO FARE
VENT P
Port 1
Separation
barrier
Port 2
Port 3
Port 4
Port 5
Inner seal
Outer seal
Labyrinths 36

37. P4 BALANCING DRUM Filtered process gas inlet Ph Ps Ps Ph Balancing
Pressure
Room
Filtered process
gas inlet P4 Ph Ps Ps Ph
BALANCING DRUM 37

38. Port 1 : Filtered process gas inlet
Separation barrier
Inner seal
Outer seal
Labyrinths
Port 4
Port 1 : Filtered process gas inlet
Port 2 : PRIMARY VENT To flare process gas + buffer gas
Port 3 : Supply of buffer gas
Port 4 : SECONDRY VENT
Port 5 : Buffer gas to separation barrier
Note 1: Maintain a differential of 0.2 bar P
Note 2: Velocity 3 – 5 m/s 38

39. REMARKS ALARM ALARM and TRIP 1- High diff. P across 2- Low pressure in
Port 1
Separation barrier
Port 2
Port 3
Port 4
Port 5
In seal
Out seal
ALARM
1- High diff. P across
filter of :
a- filtered process gas.
b- buffer gas.
ALARM and TRIP
2- Low pressure in
primary vent
(Port2 )
due to defective
secondary seal.
1- High pressure (due to excess flow)
in primary vent.
2- Low buffer gas pressure. 39

40. TO PREVENT PRODUCT GAS LEAK
1-FILTERED GAS
TO PREVENT PRODUCT GAS LEAK
2- SUPPLY OF BUFFER GAS ( N2 OR AIR )
TO PRVENT FILTERED GAS LEAK
3- BUFFER GAS TO SEPARATION ZONE
TO PREVENT JOURNAL BEARING OIL TO
GET IN MECHANICAL SEAL 40

41. Dry Nitrogen Circuit Non-Contacting Seals Pressure Gage Regulator Ball
Valve
Pressure
Gage
Regulator
Nitrogen
Source
Flow
Meter
Seal
Chamber 41

42. oil Seal gas nitrogen nitrogen
Mechanical seal and bearings arrangement
Seal gas
nitrogen
Equipment
nitrogen
oil 42

43. NO SEAL OIL CONSUMPTION
WHY TO USE DRY SEAL INSTEAD OF WET SEAL
NO SEAL OIL CONSUMPTION
NO GAS / OIL CONTAMINATION
NO WEAR
LOW POWER CONSUMPTION
PERMITS HIGHER VELOCITY&PRESSURE 43

44. Dry Gas seal is a self adjusting Seal44

45. ( Principle of operation)
Spiral grooves
Groove
diameter
Inner
Sealing dam
Rotating ring
Carbon
ring
GAS
Rotating ring
Tungsten carbide 45

46. Pressure distribution
Forces acting on the seal
Compression
Expansion
Gas film
Pressure distribution FO
Opening force
Closing force FC
FC = FO
Normal operation
Spring
load
Product
pressure 46

47. Pressure distribution
If Gap increased
Compression
Expansion
Gas film
Pressure distribution FO
Opening force
Closing force FC
Spring
load
Product
pressure
FC FO 47

48. Pressure distribution
Gap will be reduced
FC FO
Compression
Expansion
Gas film
Pressure distribution FO
Opening force
Closing force FC
Spring
load
Product
pressure 48

49. Pressure distribution
Back To Normal operation
Compression
Expansion
Gas film
Pressure distribution FO
Opening force
Closing force FC
Spring
load
Product
pressure
FC = FO
Normal operation 49