Flowserve_pump_gas_seals.ppt

Flow Solutions Division

Dual Gas SealsDual Gas Sealsfor Pumpsfor Pumps


Advantages of Dual Gas SealsAdvantages of Dual Gas Seals

• No product emissions – gas pressure provides barrier to product leakage

• No product contamination– uses inert barrier gas such as nitrogen

• No seal face wear– noncontacting APGS face technology

• Protected from off-design pump operation– tolerant of vibration, cavitation, dry running


Advantages of Dual Gas SealsAdvantages of Dual Gas Seals

• Minimal power consumption, no heat generation– 15-20 times less energy loss than liquid seals

• Simplified barrier support system– unitized control panel– dead-ended gas supply– no external cooling required

• Low total operating cost– no routine maintenance– inexpensive barrier gas


Liquid Seal Support SystemLiquid Seal Support System

Pressure gage, regulator, barrier fluid,

pressure supply, compatible barrier

fluid, supply tank, cooling water,

circulating

device, barrier piping

loop, inner seal

flush, routine

supply tank filling,

disposal of used

barrier fluid


Why

• no product emissions

• vibration, dry running

• dry running

• emissions, dry running

• product contamination,

total operating cost

Typical Gas Seal ApplicationsTypical Gas Seal Applications

Where

• VOC’s

• Cavitating pumps

• Batch operations

• Replace single seal

• Replace dual seal


Technology ConsiderationsTechnology Considerations

• Groove pattern design - film stiffness, low speed lift-off, gas consumption • Secondary seal drag - seal face hang up• Operating conditions - seal face distortion,

vibration, batch operation• Product effects - solids, polymers, etc. • Gas reliability - barrier system design• Safety during upset events - pressure

reversal, reverse rotation, slow speed


Advanced Pattern Groove SystemAdvanced Pattern Groove System

Shallow TaperedSpiral Groove

Land

ShallowAnnularGroove

Sealing Dam


Advantages of APGS TechnologyAdvantages of APGS Technology

• Patented tapered depth and tapered width spiral grooves with unifying circumferential groove

• High film stiffness with low gas leakage

• Adaptable to various application types: – high speed, high pressure compressors– low speed mixers– variable speed pumps

• Over 2500 installations in pump gas seal and compressor services


Flowserve Pump Gas SealsFlowserve Pump Gas Seals

• GF-200– Face to face pusher design– Fits large bore seal chambers only– High pressure capability– Extensive exotic materials availability

• GX-200– Common rotor welded metal bellows design– Fits both small bore and large bore seal chambers– Solids resistance features– Pressure reversal product containment



1) Gas enters wide and deep grooves at OD

2) Gas is compressed through narrowing spiral grooves

3) Gas pressure is equalized through circumferential groove

12

3


GF-200 Hydraulic PrinciplesGF-200 Hydraulic Principles

Hydrostatic

Spring

Fo1 > Fo > Fo2

h1 < h < h2

h

Static: Fo < Fc, seal faces closedDynamic: Fo = Fc, seal faces separated by gap, hUpset: Fo1 > Fc, faces separated by new gap, h1 < h

APGS film stiffness provides stability to upset conditions.

h 0.0001” (2.54 m)

Closing Forces, FcOpening Forces, Fo


Robust Seal Face GeometriesRobust Seal Face Geometries

Designed with custom analytical techniques and proven by extensive correlation testing and field experience, seal face deflections are minimized for reliable performance.

Flat reaction surfaceFlat reaction surface Uniform drive loadUniform drive load Flat spring retainerFlat spring retainer

Premium quality materialsPremium quality materials


Patented LoDrag™ O-ring DesignPatented LoDrag™ O-ring Design

Canted coil spring positioned above dynamic O-ring compensates for thermal expansion and chemical swell, providing consistent loading and low friction drag to reduce seal face hang-up.

Canted coil springCanted coil spring Dynamic O-ringDynamic O-ring

Highly polished sleeveHighly polished sleeve


GF-200 Design FeaturesGF-200 Design Features

Requires large boreseal chamber

Requires large boreseal chamber

Simple installation cartridge seal is100% static tested at the factory


Dead-ended barrier gas



Solids HandlingSolids Handling

Integrating a bushing into the product end of the cartridge can reduce the opportunity for solids from the process stream to enter the seal area and cause secondary seal hang-up or erosion.

Self-cutting labyrinth bushingSelf-cutting labyrinth bushing

Teeth built into cartridge sleeveTeeth built into cartridge sleeve


GF-200 Operating LimitsGF-200 Operating Limits

Product Pressure: 500 psig (34.5 bar)

Barrier Pressure: 25 psi (2 bar) minimumover product pressure

Temperature: -40 to 500 F (-40 to 260 C)

Minimum Speed: 500 ft/min (2.5 m/sec)

Maximum Speed: 7000 ft/min (25 m/sec)

Seal Sizes: 1.000” to 6.000” (25.4 mm to 150 mm)


GF-200 Estimated Gas ConsumptionGF-200 Estimated Gas Consumption

0

1

2

3

4

5

6

7

8

0 100 200 300 400 500

Seal Chamber Pressure (psig)

Co

nsu

mp

tio

n F

acto

r (C

F)

1.125" (28 mm)

1.375" (35 mm)

1.625" (40 mm)

1.875" (48 mm)

2.375" (60 mm)

2.750" (70 mm)

4.750" (121 mm)

Barrier Gas Pressure = Seal Chamber Pressure + 50 psig

Total Gas Consumption (SCFH) = CF x RPM / 1000Total Gas Consumption (NL/hr) = CF x RPM / 35.31


GX-200 Gas Barrier SealGX-200 Gas Barrier Seal


GX-200 Design FeaturesGX-200 Design Features

Inboard seal

Stationary carbon facesStationary carbon faces

Common rotor silicon carbide with APGSCommon rotor silicon carbide with APGS

Outboard seal

Patentedoverall design

Patentedoverall design

Mounts completely outside seal chamber

Mounts completely outside seal chamber



1) Gas enters wide and deep grooves at OD

2) Gas is compressed through narrowing spiral grooves

3) Gas pressure is equalized through circumferential groove

12

3


GX-200 Hydraulic PrinciplesGX-200 Hydraulic Principles

Static: Fo < Fc, seal faces closedDynamic: Fo = Fc, seal faces separated by gap, hUpset: Fo1 < Fc, faces separated by new gap, h1 > h

APGS film stiffness provides stability to upset conditions.

h

Hydrostatic

Spring

Closing Forces, Fc Opening Forces, Fo

Fo1 < Fo < Fo2

h1 > h > h2h 0.0001” (2.54 m)


Robust Seal Face GeometriesRobust Seal Face Geometries

Designed with custom analytical techniques and proven by extensive correlation testing and field experience, seal face deflections are minimized for reliable performance.

Flat reactionsurface

Flat reactionsurface

Tangential drive loadsTangential drive loadsRectangular cross sectionsRectangular cross sections

Uniform hydraulicand spring load

Uniform hydraulicand spring load

Premium quality materialsPremium quality materials


Welded Metal BellowsWelded Metal Bellows

Patented, unitized welded metal bellows eliminate dynamic secondary seals for excellent seal face tracking and solids resistance. With an upset pressure reversal, inboard seal faces contact to contain product.

Bellows closesoff during upset

pressure reversals

Bellows closesoff during upset

pressure reversals

No drive torquethrough bellows

No drive torquethrough bellows

Interchangeable inboard and outboard capsules

Interchangeable inboard and outboard capsules


Solids ResistanceSolids Resistance

Patent pending tapered retaining plate protects bellows ID and seal face region by redirecting process solids toward the seal chamber. The bellows remain clean with no opportunity to hang-up.

Redirected process solids

Redirected process solids

Tapered retaining plate ID

Tapered retaining plate ID


GX-200 TARSEx BushingGX-200 TARSEx Bushing

The TARSEx bushing restricts solids from the seal area by creating a static and dynamic barrier through cooperation with the tapered retaining plate. TARSEx stands for Tapered Annulus Radial Solids Exclusion.

Radial vanes throw solids toward the OD

Radial vanes throw solids toward the OD

Bushing can be separate add-on or unitized into cartridge

Bushing can be separate add-on or unitized into cartridge

Sealing dam aids static solids restriction

Sealing dam aids static solids restriction


GX-200 Design FeaturesGX-200 Design Features

Fits any size seal chamber

Fits any size seal chamber






GX-200 Operating LimitsGX-200 Operating Limits

Product Pressure: 200 psig (34.5 bar)

Barrier Pressure: 25 psi (2 bar) minimumover product pressure

Temperature: -40 to 500 F (-40 to 260 C)

Minimum Speed: 500 ft/min (2.5 m/sec)

Maximum Speed: 7000 ft/min (25 m/sec)

Seal Sizes: 1.000” to 3.000” (25.4 mm to 76 mm)


0

0.5

1

1.5

2

2.5

0 25 50 75 100 125 150 175 200

Seal Chamber PressureBarrier Gas Pressure = Seal Chamber Pressure + 50 psig (4 bar)

Co

nsu

mp

tio

n F

acto

r (C

F)

1.125" (28 mm)

1.375" (35 mm)

1.625" (40mm)

1.875" (48 mm)

2.125" (53 mm)

2.375" (60 mm)

2.750" (70 mm)

Total Gas Consumption (SCFH) = CF x RPM / 1000Total Gas Consumption (NL/hr) = CF x RPM / 35.31

psig

0 2 4 6 8 10 12 14 bar

Seal/Shaft Size

GX-200 Estimated Gas ConsumptionGX-200 Estimated Gas Consumption


Barrier Gas SystemBarrier Gas System

Pressuregage

5 micronfilter

RegulatorFlow meter

From gasheader

To seal

Options:Pressure alarm

Check valveOrifice

Booster pump3-way valve


Application ConsiderationsApplication Considerations

• Barrier Gas Reliability– Pressure reversals are a primary reason for seal upset– Install alarms and emergency backup supply

• Fluids with Solids– Gas seals are not slurry seals - product at seal face ID– Gas may cause dissolved solids to come out of solution– Use bushings to keep solids from seal faces

• Reverse Rotation of Pumps– APGS gas seal faces contact when reverse rotated– Check piping, shutdown procedures, and motor wiring


Application ConsiderationsApplication Considerations

• Transient Slow Speed Cycles– Check all equipment cycles for minimum speeds– Minimize start and stop parameters on VFD’s

• Stand-by Pumps– Small static gas leakage can accumulate over time– Properly vent pump before start-up

• Low Flow / Low Suction Head Pumps– Centrifugal pumps can tolerate 1-2% entrained gas– Gas leakage expands in low pressure suction– Evaluate gas percentage at lowest pressure point


GX-200 Case HistoryGX-200 Case History

• US Navy - Fuel oil and lube oil vertical pumps– Problem: Single seals on US Navy ships could not

maintain zero emissions with dry running at startup and 0.035" axial shaft movement.

– Solution: Standard GX-200 satisfied all requirements including military shock and vibration testing. Shock testing simulated the shock wave of a conventional or nuclear weapon upon explosion - a 400 lb hammer dropped 5 feet imparting 500 gravities. Vibration testing looked for resonant frequencies from 5-50 Hz at amplitudes up to 0.030” (0.76 mm).


ConclusionsConclusions

• Flowserve Flow Solutions Division GF-200 and GX-200 noncontacting seal face gas barrier seals provide extended pump reliability solutions using proven, patented technologies.

• Zero product emissions, no contamination of the product, no seal face wear, tolerance of off-design pump operation, negligible energy consumption, simple installation, and low maintenance requirements add up to low total operating costs.



• APGS face design produces a stable gas film for consistent loading, early face separation, high film thickness, and low gas leakage.

• The GF-200 is a face to face pusher design using LoDrag™ energized O-rings to minimize secondary seal drag. Fitting only on large bore seal chambers, it is capable of sealing 500 psi (34.5 bar) with a variety of optional materials of construction.



• The GX-200 is a common rotor design which eliminates secondary seal drag altogether with Alloy C-276 or Alloy 718 bellows. It fits any seal chamber size by mounting entirely outside and has standard solids tolerance features.

• Ask Flowserve for information about gas seal solutions for other equipment such as mixers, compressors, or steam turbines where low speed, high pressure, and/or high temperature create difficult sealing environments.


Other FlowserveOther FlowserveGas SealsGas Seals


Flowserve Gas Seal ProductsFlowserve Gas Seal Products

Product Technology Arrangement Equipment Special Feature

GSD Contacting Backup API Emergency containment

GSL Wavy Backup API High duty containment

GB-200 Hydropads Double ANSI big bore Pressure reversals

GF-200 APGS Double ANSI big bore Low drag O-rings

GX-200 APGS Double ANSI small bore Metal bellows

GF-300 APGS Tandem API Flashing hydrocarbons

GTS Wavy Single Steam Turbine High temperature steam

GSS Wavy All Sundyne High speed, small size

Gaspac APGS, T-groove All Compressor High speed, large size

VRA Contacting Single/Double Mixers Low speed

ML-200 APGS Double Mixers Low speed

Flowserve_pump_gas_seals.ppt

Documents

seal faces

gas consumption secondary

single seal

seal area

seal sizes

barrier pressure

seal face hangup

inert barrier gas