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STATIC AND DYNAMIC SEALS
• DEFINITIONS
• MECHANICAL AND GAS SEAL
• IDENTIFYING SEAL PROBLEMS
• SEAL ENVIRONMENTAL CONTROL
STATIC SEAL DEFINITION
• O-rings Elastomers
• O-rings Graphite, Teflon®, Kalrez®...
• Gaskets Flexitallic®…
• Not very effective with relative motion between adjacent surfaces.
• More details in O-ring section
SEAL DEFINITION
Used where there is relative motion between adjacent surfaces
Mechanical seals
Lip and labyrinth seals
Circumferential seals
SEAL CAVITY PRESSURE
BETWEEN IMPELLER AND SEAL FACE
HIGHER THAN SUCTION AND LOWER THAN DISCHARGE PRESSURE
SOMEWHAT HIGHER WITH INDUCER
MUCH HIGHER THAN SUCTION ON FULL EMISSION
APPROXIMATELY 70% OF DISCHARGE PRESSURE
SEAL CAVITY PRESSURE
SEAL CAVITY PRESSURE IMPORTANT FOR SEAL SELECTION
CALCULATED VALUE ON SPECIFICATION SHEET
ACTUAL VALUE MAY BE SOMEWHAT DIFFERENT
CAVITY PRESSURE CONTROLLED BY SPEED, FLOW, IMPELLER AND INDUCER
WITH INDUCER
WITHOUT INDUCER
FLOW - GPM
SEA
L C
AV
ITY
PR
ES
SU
RE R
ISE
TYPICAL CURVE SHAPE FORSEAL CAVITY PRESSURE RISE vs. FLOWRATE
(FOR ILLUSTRATION ONLY)S
EA
L C
AV
ITY
PR
ES
SU
RE R
ISE
WITH INDUCER
WITHOUT INDUCER
SPEED - RPM
TYPICAL CURVE SHAPE FORSEAL CAVITY PRESSURE RISE vs. SPEED
(FOR ILLUSTRATION ONLY)
EFFECTS OF FLOW AND SPEED ON SEAL CAVITY PRESSURE
MECHANICAL SEAL CROSS SECTION
STATIONARY FACECARBON
ROTATING FACE(TUNGSTEN CARBIDE)
RETAINER
SPRINGS
SECONDARY SEALTEFLON WEDGE OR
O-RING
PRIMARY SEAL(SEAL INTERFACE)
aca o
Mechanical Seal Cross Section
PROCESS MECHANICAL SEALS
SEALS ARE BALANCED
Mathematical definition b=Ac/Ao
“EXTERNALLY” PRESSURIZED : HIGHER PRESSURE AT NOSE O.D
HARD FACE ROTATES
FLEXIBLE ELEMENT IS STATIONARY
API 682
PRIMARY AND SECONDARY SEAL
“PRIMARY” RELATES TO INTERFACE OF NOSE AND ROTATING FACE
“SECONDARY” RELATES TO O-RING OR WEDGE RING
PRIMARY SEAL INSPECTED WHEN PROBLEMS ARISE
SECONDARY SHOULD ALSO BE CAREFULLY INSPECTED
SEAL TYPE AND ARRANGEMENT
ROTATING FACE IN A SUNDYNE IS THE HARD FACE
SEAL NOSE IS STATIONARY PART
CONTRARY TO PRACTICE IN MOST CENTRIFUGALS
SEAL TYPE CATEGORIZED 8AB, 9AB OR BELLOWS
9AB=WEDGE RING8AB=O-RING
SEAL FACE MATERIALS
CARBON VS TUNGSTEN CARBIDE. BY FAR MOST COMMON
OTHER MATERIALS SUCH AS SiC AVAILABLE
RA = PURBIDE 658RC OR EQUIV
RW = P-75 EXTREME CORROSIVE. ie HF
RH = P-87 HOT WATER>300F
ROTATING FACE MATERIALS
RE = TUNGSTEN CARBIDE WITH COBALT- WIDE RANGE USE
RJ = TUNGSTEN CARBIDE WITH NICKEL- WATER, AMMONIA AND OTHERS
DISCLAIMER
THE SEAL ARRANGEMENTS MENTIONED AND DISPLAYED WITHIN THIS SECTION ARE CONSIDERED TO BE STANDARD
THERE ARE VARIATIONS TO THESE ARRANGEMENTS WHICH MAY BE APPLICABLE, BUT NOT MENTIONED
SUNDSTRAND IS CONTINUALLY ENGINEERING NEW SEAL TECHNOLOGY
ARRANGEMENTS
SINGLE
TANDEM - DUAL UNPRESSURIZED –
DOUBLE
EASILY CHANGED
ACCOMMODATE CHANGE OF OPERATING CONDITIONS OR SERVICE
SINGLE SEAL
MOST SIMPLE OPTION , LEAST EXPENSIVE OPTION
CLEAN PROCESS, CLEAN FLUSH OR SEPARATOR NEEDED
THROTTLE BUSHING STANDARD - DIRECTS LEAKAGE TO DRAIN PORTS, NEEDED WHEN QUENCH OR PURGE IS USED
SINGLE SEAL
SINGLE SEAL
SLINGERSLEEVEASSEMBLYTHROTTLE
BUSHING
SPRING
WEDGE RING
STATIONARYFACE
ROTATINGFACE
TANDEM SEALS - DUAL UNPRESSURIZED -
USE WHEN PRESSURE EXCEEDS SINGLE CAPABILITY, OR TO MEET EMISSION STANDARDS
PROVIDE SHUTDOWN SIGNAL OR A BACK-UP SEAL
API PLAN 52 OR 53 BUFFER SYSTEM WITH LIQUID SEAL
(except if upper seal is gas seal in case of volatile components)
OPTIONAL UPPER GAS SEAL ARRANGEMENT ELIMINATES NEED FOR API 52 BUFFER SYSTEM
PRESSURIZE WET END (PUMP) FIRST, THEN SEAL
GEARBOX SEAL
UPPER SEAL
LOWER SEAL
GEARBOX MATING RING
UPPER SEAL
MATING RING
LOWER SEAL
MATING RING
TANDEM SEALS - DUAL UNPRESSURIZED -
TANDEM SEAL
STATIONARYFACE
ROTATINGFACE
ROTATINGFACE
LOWERSHAFTSLEEVE
UPPERSHAFTSLEEVE
TANDEM SEALS - DUAL UNPRESSURIZED -
DOUBLE SEALS- DUAL PRESSURIZED -
CLEAN FLUSH NOT AVAILABLE, PROCESS FLUID CONTAMINATED
HAZARDOUS/TOXIC PROCESS - NO OVERBOARD LEAKAGE TOLERATED
MINUTE BUFFER LEAKAGE INTO PROCESS
COMMON ROTATING FACE
API PLAN 53 PRESSURIZED BARRIER SYSTEM.(2-3BAR>SCP)
PRESSURIZE BUFFER FIRST, THEN WET END (PUMP)
GEARBOX SEAL
UPPER SEAL
LOWER SEAL
GEARBOX MATING RING
PROCESS SEALS
MATING RING
DOUBLE SEALS- DUAL PRESSURIZED -
DOUBLE SEAL
STATIONARYFACE
SPACER
ROTATINGFACE
LOWERSHAFTSLEEVE
UPPERSHAFTSLEEVE
DOUBLE SEALS- DUAL PRESSURIZED -
DOUBLE SEALSON SITE CASE
API 53B PROVIDED
CUSTOMER SUCTION PRESSURE = ± 10 Barg
BUFFER RECOMMANDED PRESSURE = 40 Barg
PROCESS LINED UP FIRST IN THE PUMP CASING AND THEN PRESSURIZING BUFFER POT
SEALS ARE NOT ABLE TO RETAIN BUFFER LIQUID. WHY?
SHAFT SLEEVES
• ALL SUNDYNE UNITS FEATURE DRY SHAFT DESIGN
• TORQUING OF IMPELLER IS MOST IMPORTANT
• SLEEVES- CORROSION RESISTANT MATERIAL. SEALED AT BOTH ENDS WITH O-RINGS. NO PROCESS FLUID ON SHAFT
• AXIAL COMPRESSION OF SLEEVES, MATING RINGS AND IMPELLER
• SLEEVE ENDS MUST BE PARALLEL AND FLAT
SHAFTROTATING FACEG.BOX OIL SEAL
SLEEVE
ROTATING FACE(OUTBOARD)
ROTATING FACE(INBOARD)
IMPELLERINDUCER
WHAT IS WRONG WITH THIS PICTURE?
HIGH-SPEED SHAFT ASSEMBLY
WHAT IS RIGHT ?
NO ‘O’-RING BETWEEN HSS AND GEARBOX SEALROTATING FACE
YES, ‘O’-RINGS ARE INSTALLEDBETWEEN ALL OTHERS HS
ASSEMBLY STACK UP PARTS
GAS SEALS
SIMILAR TO PUMP SEALS- FIT THE SAME ENVELOPE
BALANCED SEALS
DIVIDED INTO LOW AND HIGH PRESSURE TYPES
SPRINGS MAY BE NESTED COIL OR GARTER
SPRING FORCE IS 25% OF WHAT IT IS IN PUMP SEALS
GAS SEALS
ALL HAVE SOME FORM OF LIFT-OFF PAD OR SCROLL TO PROVIDE GAS FILM LUBRICATION
ACTUALLY A CONTROLLED LEAKAGE DEVICE. MUST LEAK IN ORDER TO PERFORM SATISFACTORILY
GAS SEALS
NEVER APPLY LUBRICANT TO GAS SEALS
KEEP FINGERS OFF THE SEAL FACES!
MAKE SURE SLEEVES ARE PARALLEL AND FLAT
CHECK FREEDOM OF SEAL NOSE IN RETAINER. SPRING LOAD IS VERY LOW. NOSE MUST BE FREE
FLATNESS
1"1"
POINT OFCONTACT*
POINT OFCONTACT*
The light bands are curved. The curve is one whole light band in one inch so the flatness is in error 11.6 millionths of an inch (.295mm) in one inch (25µm) length. Since the lines curve toward the point of contact the surface is concave.
The light band curve shows two light bands between the end of the arc and the crown which means this part is out of flat 23.2 millionths of an inch (.589 µm). Since the lines curve away from the point of contact the surface is convex two light bands in one inch or four light bands in two inches, six light bands in six inches, etc. In other words the error of the light band is directly proportional to the length.
CONING
POSSIBLEEDGECHIPPING
HEAVY TO MODERATECONTACTNO CONTACT
SIMILARPATTERN ONPRIMARY RING
DEFLECTION OF PRIMARY RING DUE TO PRESSURE
POSSIBLEEDGECHIPPING
HEAVY TO MODERATECONTACT
NO CONTACTSIMILARPATTERN ONPRIMARY RING
DEFLECTION OF MATING OR PRIMARY RING DUE TO TEMPERATURE
THERMAL DISTORTION(Positive Rotation)
MECHANICAL DISTORTION
NO CONTACT
HIGH SPOTS
POSSIBLE EROSION OF THE PRIMARY RING (WIRE DRAWING) IF ALLOWED TOREMAIN STATIONARY
POSSIBLE EROSION OF THE PRIMARY RING(WIRE BRUSHING) IF ALLOWED TO ROTATE. OUT-OF-FLAT MATING SURFACE WILL CAUSE DIRT TO ENTER THE SEAL AREA
EXCELLENT CONDITIONAFTER SHORT STATICAND DYNAMIC TESTS
HIGH WEAR OR THERMALLY DISTRESSED SURFACE
SURFACE CRACKSREFERRED TO ASHEAT CHECKING
POSSIBLE EDGECHIPPING ON OD AND ID
POSSIBLEWEAR AT DRIVENOTCHES
PATCHES OF THERMALLY DISTRESSED SURFACES
GOOD CONTACTPATTERN
DISTRESSED SURFACEOR HOT SPOT
POSSIBLE WEAR ATDRIVE NOTCHES
HIGH WEAR AND GROOVING
DEPTH OF GROOVE
FULL CONTACT PATTERN
POSSIBLE EDGE CHIPPING OF SOFT CARBON PRIMARY RINGS. EDGES WILL BE ROUNDED FOR HARD MATERIAL OF CONSTRUCTION LIKE TUNGSTEN CARBIDE
POSSIBLE WEARAT DRIVE NOTCHES
OUT OF SQUARE MATING RING
HIGHLY POLISHED AREA POSSIBLE. SLIGHTLY WIDER CONTACT
AREA ON MATING RING
WEAR ATDRIVENOTCHES
SEAL RETAINER INSPECTION
INSPECTFOR WEAR
SPRINGS
SECONDARY SEAL BACKUP DISC
INSPECT FOR RUBS
CHECK ANTI-ROTATION PIN FOR WEAR
CHECK SEAL RETAINER CAREFULLY.
CENTER POST, SECONDARY CONTACT AREA, RETAINER I.D., SPRINGS AND ETC.
API PLANS
• IMPORTANT TO CREATE A SEAL ENVIRONMENT THAT IS:
• COOL
• CLEAN
• LUBRICATING
• WITHIN PRESSURE CAPABILITY OF SEAL
• PROCESS COMPATIBLE
API PLANS
Insure seal system is properly installed and functioning
See API Plan Schematics in The SEAL BULLETIN
API flush, buffer, cooling plans should be properly handled at manufacturing and installation
GEARBOX SEAL
UPPER SEAL
PROCESS SEAL
GEARBOX
DRAIN CAVITY
BUFFER CAVITY
SEAL CAVITY
PUMP SUCTION
PUMP DISCHARGE
PORT 1
PORT 2
PORT 6
PORT 7
PORT 5
PORT DESIGNATION
311 / 3311: DRAIN2: BUFFER OUT3: COOLING MANTEL IN4: COOLING MANTEL OUT5: SEAL CAVITY (IN)6: SEAL CAVITY (OUT)7: BUFFER IN
3221: DRAIN2: BUFFER IN3: N/A4: N/A5: SEAL CAVITY (IN)6: SEAL CAVITY (OUT)7: BUFFER OUT
API PLAN 11
DISCHARGE
65
1
7 2
SUCTION
DRAIN CAVITY
GEARBOX
BUFFER CAVITY
SEAL CAVITYPROCESS SEAL
UPPERSEAL
GEARBOX SEAL
FLUSH INTO PORT 5 OR 6
API PLAN 11
API PLAN 21
DISCHARGE
65
1
7 2
SUCTION
DRAIN CAVITY
GEARBOX
BUFFER CAVITY
SEAL CAVITY
PROCESS SEAL
UPPERSEAL
GEARBOX SEALAPI PLAN
21 COOLED FLUSH INTO PORT
5 OR 6
API PLAN 13
DISCHARGE
65
1
7 2
SUCTION
DRAIN CAVITY
GEARBOX
BUFFER CAVITY
SEAL CAVITY
PROCESS SEAL
UPPER SEAL
GEARBOX SEALAPI PLAN 13
API PLAN 31
SUCTION
DISCHARGE
65
1
7 2
DRAIN CAVITY
GEARBOX
BUFFER CAVITY
SEAL CAVITY
PROCESS SEAL
UPPER SEAL
GEARBOX SEALAPI PLAN 31
API PLAN 41
DISCHARGE
65
1
7 2
SUCTION
DRAIN CAVITY
GEARBOX
BUFFER CAVITY
SEAL CAVITY
PROCESS SEAL
UPPER SEAL
GEARBOX SEALAPI PLAN 41
API PLAN 52
DISCHARGE
65
1
72
SUCTION
DRAIN CAVITY
GEARBOX
BUFFER CAVITY
SEAL CAVITY
PROCESS SEAL
UPPER SEAL
GEARBOX SEAL
API PLAN 52
ADDITIONAL COOLINGIMPROVES
THERMOSYPHONEFFECT (OPTIONAL)
API PLAN 53
DISCHARGE
65
1
72
SUCTION
DRAIN CAVITY
GEARBOX
BUFFER CAVITY
SEAL CAVITY
PROCESS SEAL
UPPER SEAL
GEARBOX SEAL
ADDITIONAL COOLINGIMPROVES THERMOSYPHON
EFFECT (OPTIONAL)
API PLAN 53
RECIRCULATION FROM PRESSURIZED OR UN-PRESSURIZED RESERVOIR TO SEAL HOUSINGWITH PROCESS COMPATIBLE BUFFER FLUID
(THERMOSYPHON/FORCED CIRCULATION WITH ROTATING SEAL FACE)
API PLANS 52 & 53
SLOPING LINES
AVOID ELBOWS
LIQUID TO ENTER BUFFER VESSEL IN LIQUID SIDE
PROPERLY SIZED LINES
SELECT PROPER PUMP CONNECTION PORTS
API PLAN 52/53REQUIREMENTS
DRAIN PORT CONNECTIONS
TO FLARE
OIL DRAIN
Discharge
65
1
72
Suction
DRAIN CAVITY
GEARBOX
BUFFER CAVITY
SEAL CAVITY
PROCESS SEAL
UPPER SEAL
GEARBOX SEAL
TO FLARE
OIL DRAIN
DISCHARGE
65
1
72
SUCTION
DRAIN CAVITY
GEARBOX
BUFFER CAVITY
SEAL CAVITY
PROCESS SEAL
UPPER SEAL
GEARBOX SEAL
COMBINATION OF PLANS
TYPICAL SEALS CONFIGURATIONS
Serial number Item number Duty ModelSeal
configurationLower seal Upper seal
O-ring material
D-870217-1-A/B 14-G-022/S Wash water LMV-311 Single SE04AA47R 11 61 UDD-870217-3-A/B 15-G-020/S Lean Amine LMV-311 Dual Pressurized SE04AA47R SE04AA48P 53 UDD-870217-4-A/B 15-G-021/S Slop oil LMV-322 Dual Pressurized SE04AA12T SE04AA18S 53 UCD-870217-6-A/B 402-G-004_A/B Wash water LMV-322 Single SE04AA12A 11 61 UCD-870217-8-A/B 409-G-004_A/B Wash water LMV-322 Single SE04AA12A 11 61 UCD-870217-10-A/B 413-G-003_A/B Hydrocarbon LMV-322 Dual UnpressurizedSE04AA10A SE04AD08F 13 UCD-870217-12-A/B 415-G-004_A/B Wash water LMV-311 Single SE04AA12A 11 61 UCD-870217-14-A/B 415-G-005_A/B Lean Amine LMV-311 Dual Pressurized SE04AA47R SE04AA48P 53 UDD-870217-16-A/B 415-G-009_A/B Hydrocarbon LMV-322 Single SE04AA12A 11 61 UCD-870217-18-A/B 415-G-010_A/B Condensate LMV-802 Single SE044AA47M 11 61 UDD-870217-20-A/B 418-G-107_A/B Butane LMV-322 Dual UnpressurizedSE04AA10A SE04AD08F 13 UC
Serial number Item number Duty ModelSeal
configurationLower seal Upper seal
O-ring material
C-240021-1-A 413-K-102 Blower LMC-311P Single SE04AA07F UC
API plans
API plans
COMPRESSOR
PUMP
List of pumps / compressorTAKREER -- Technip Italy
TO REMEMBER
What are the 3 seals configurations ?What is the working height of the mechanical seal? How to
measure it?
TRUE OR FALSE:1. The seal cavity pressure rise is higher on a full emission pump.
2. The seal selection is not related to the seal cavity pressure.
3. The stationnary face of the seal is the hard face.
4. It is necessary to change the seal housing to modify the seal configuration.
5. All Sundyne seals can handle reverse pressure.
6. Port 1 must be always opened.