01 - 1 Pump - Floater vs Compression

7/18/2019 01 - 1 Pump - Floater vs Compression

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S ch l um b er g er P

r i v a t e

Centrifugal Pump




r i v a t e

Centrifugal Pumps

The term “centrifugal pump” has been used todescribe a wide variety of pumping applicationsand designs throughout the years.




r i v a t e

Centrifugal Pump

The REDA centrifugal pump is amultistage pump, containing a

selected number (application

dependent) of impellersequipped with vanes, inside a

closely fitted diffuser, located

in series an axial shaft, drivenby the electrical motor.




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Centrifugal Pump

A centrifugal pump creates pressure by the

rotation of a series of vanes in an impeller.

The impeller’s job is to transfer energy byrotation to the liquid passing through it, thusraising the kinetic energy.




r i v a t e

Centrifugal Pump

The diffuser section then converts this energy topotential energy, raising the discharge pressure.




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Centrifugal Pump

From there, the rotation of thehigh-speed impeller throws

the liquid into the diffuser.




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Centrifugal Pumps

Each "stage" consists of an impeller

and a diffuser. The impeller takes thefluid and imparts kinetic energy to it.

The diffuser converts this kinetic

energy into potential energy (head or

pressure).

UpthrustUpthrustUpthrustUpthrust WasherWasherWasherWasher

ImpellerImpellerImpellerImpeller

Down Thrust WasherDown Thrust WasherDown Thrust WasherDown Thrust Washer

DiffuserDiffuserDiffuserDiffuser



S ch l um b er g er P r i v a t e

• Curves for centrifugal

pumps are normallyshown as flow versushead in feet, meters, or

some other consistentunit.

Head: The height

to which the pumpwill "lift" the fluid

HEAD




• A centrifugal pump produces "constant head".

– This means that, regardless of the fluid being

pumped, it will be lifted to the same height asany other fluid for the same flow rate.

Propane Water Oil




0 2000010000 30000

20000

10000

0 T o t a l D y n a m i c H e a d - F

e e t

15000

5000

Flow Rate - BPD (60 Hz)

Maximum Head-Capacity

5.5" Casing7" Casing

4.5" Casing




• From this curve we can determine the head head head head

produced, brake horsepower required brake horsepower required brake horsepower required brake horsepower required andhydraulic efficiency hydraulic efficiency hydraulic efficiency hydraulic efficiency at any flow rate.

REDA

Rev. B

SN2600 60 HZ / 3500 RPM Pump Performance Curve 538 Series - 1 Stage(s) - Sp. Gr. 1.00

Optimum Operating RangeNominal Housing DiameterShaft Diameter

Shaft Cross Sectional AreaMinimum Casing Size

1600 - 32005.38

0.875

0.6017.000

bpd inches inches

in2 inches

Shaft Brake Horsepower Limit:

Housing Burst Pressure Limit:

StandardHigh StrengthStandard

ButtressWelded

256410N/A

60006000

Hp Hp psi

psi psi

0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000

REDA

Rev. B

SN2600 60 HZ / 3500 RPM Pump Performance Curve 538 Series - 1 Stage(s) - Sp. Gr. 1.00

Optimum Operating RangeNominal Housing DiameterShaft Diameter

Shaft Cross Sectional AreaMinimum Casing Size

1600 - 32005.38

0.875

0.6017.000

bpd inches inches

in2 inches

Shaft Brake Horsepower Limit:

Housing Burst Pressure Limit:

StandardHigh StrengthStandard

ButtressWelded

256410N/A

60006000

Hp Hp psi

psi psi

EffHpFeet

Capacity - Barrels per Day

10%

20%

30%

40%

50%

60%

B.E.P.Q= 2581H = 46.75P = 1.31E = 68.09

10

20

30

40

50

60

0.50

1.00

1.50

2.00

2.50

3.00




Pump Descriptions and Names

The series designations are defined as:

Type Series Outside

Diameter

Minimum

Casing SizeA 338 3.38” 4 ½”

D 400 4.00” 5 ½”

G 540 5.13” 6 5/8”

S 538 5.38” 7”

H 562 5.63” 7”

J 675 6.75” 8 5/8”

L 738 7.25” 9 5/8”

M 862 8.63” 10 ¾”

N 950 9.5” 11 ¾”950 10.00” 11 ¾”

P 1125 11.25” 13 3/8”

DN 1300




Pump Descriptions and Names:

• Other Letters (Suffix only) used in PAD to

describe special pumps

• H (Extrude Honed)

• E (Epoxy Coated Stages) SN3600E• C (As Cast)

• Other letters may be used from time to time,

but these should be considered asexperimental and not used in pump selections.




Pump Nomenclature:Frequently Used TermsFrequently Used TermsFrequently Used TermsFrequently Used Terms

Abbreviation Definition

ARZ Abrasion Resistant: Zirconia bushings and sleeves

ARZ-S Abrasion Resistant: Silicon Carbide sleeves

ARZ-SS Abrasion Resistant: Silicon Carbide bushing and sleeves

ARZ-T Abrasion Resistant: Tungsten-Carbide sleeves

ARZ-TT Abrasion Resistant: Tungsten-Carbide bushings and sleeves

ARZ-ZS Abrasion Resistant: Zirconia bushing bushings and Silicon sleeves

ARZ-ZT Abrasion Resistant: Zirconia bushing bushings and Tungsten sleeves

C Compression

CT Center Tandem

C-CT Compression-Center Tandem

C-LT Compression-Lower Tandem

CR Compression Ring

CR-CT Compression Ring-Center Tandem

CR-LT Compression Ring-Lower Tandem

ES Enhanced StabilityFL Floater

FL-CT Floater-Center Tandem

FL-LT Floater-Lower Tandem

FL-S Floater-Single section

HB Hydraulic Balance

HSG Housing

S Single

SS Stainless Steel

SS H and B Stainless Steel Head and BaseCS Carbon Steel

M-Trim Monel Trim

Rloy Redaloy

SLB Self Lubricating bearings (Graphalloy)

HSS High Strength Shaft




Pump naming conventions

A DN1400 indicates:

D = 400 series, therefore, 4.0” in diameter

1400 = the best efficiency flow rate

(60 Hz : 3500 RPM) in barrels per day.

N = the material of the stage, in this case ni-resist.



S ch l um b er g er P r

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Pump naming conventionsA D950 indicates:

D = 400 series, or 4.0” diameter

950 = 950 bpd flow rate

“N” is missing from the description so the

impellers are Ryton (thermo plastic)




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Centrifugal PumpsThere are two types of impellers that determine the

amount flow available for the specific design.




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Centrifugal Pumps

The difference between these two types of designs

is described by the pump

impeller vane angles and the size and shape of the

internal flow passages.




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Centrifugal Pumps

A mixed flow impellerhas vane angels at

close to 45 degree, and

therefore, are usuallyfound in pump ranges

for higher flow rates.




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Centrifugal Pumps

A radial flow(pancake) impeller has

vane angels at close

to 90 degree, and therefore, are usually

found in pump ranges

for lower flow rates.




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Pump Construction

There are two types of pump stage construction

for ESP oil field applications:

Floater - TypeCompression - Type




2 Types of Stage Construction

PumpDown

ThrustCarried

here

Impeller

ThrustCompression

Floater

ProtectorThrust

Bearing

Motor

ThrustBearing




"Compression" Pumps

In a compression pump, all the impellers are rigidly fixed to the shaft

so that if an impeller wants to move up or down, it will take the shaft

with it.

The impeller is normally sitting down on its lower diffuser during

assembly due to gravity. Because of this, the pump shaft is "raised"

with shims in the coupling so that the impeller is not allowed to touch the diffuser after final assembly. This allows all thrust

developed in the pump shaft to be transferred to the protector shaft

directly.




There is a small amount of free play in the coupling

such that the pump shaft can fall down to where theimpellers ride directly on the lower diffusers or on the

downthrust washers if available.

Impeller is in full down position

Pump Shimming




When shimming 675 Series pumps

and larger (which do not have

down thrust washers), Impeller is

lifted slightly off diffuser.

Shims placed in

coupling to raise

the shaft

Pump Shimming




If we are shimming 562 Series

pumps and smaller (which

have downthrust washers) wematch the shafts flush.

Shims placed incoupling to match

the shafts

Pump Shimming




Why use Compression Pumps?

• Some stages generate too much thrust to be handled by a thrust washer in

the stage.• Some fluids (e.g. liquid propane) do not have enough lubricity to properly

lubricate a thrust washer.

• If abrasives or corrosives are present, it may be beneficial to handle the

thrust in an area lubricated by motor oil rather than well fluid.• Occasionally in very gassy wells, the flow volume changes so drastically

within the pump that parts of a floater pump could be in very severe thrust

while others are not so a compression pump could be one alternative.

• Since all the thrust is handled in the protector, as long as the protector has a

great enough capacity, the pump operating range can be extended over amuch wider area without any increased wear or reduced life.




"Floater" Pumps

Why use a floater pump?

Let's look at a floating impeller in detail.




Floating Impellers:

Since a floating impeller is free to move up and down the shaft, the only thing to stop

it is either the upper or lower diffuser. "Thrust washers" are provided at all mating

surfaces between the impeller and diffuser to absorb any thrust generated.

Thrust

Washers



S ch l um b er g er P r i

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Floating Impellers:

The blue area shows the "upthrust" washer between the

impeller and upper diffuser.

Force

Upthrust isUpthrust isUpthrust isUpthrust is

absorbedabsorbedabsorbedabsorbed

herehereherehere




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Floating Impellers:

The blue area shows the "downthrust" washers between the

impeller and lower diffuser.

DownthrustDownthrustDownthrustDownthrust

is absorbedis absorbedis absorbedis absorbed

herehereherehere

Force




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Floating Impellers:

Seal hereSeal hereSeal hereSeal here

preventspreventspreventsprevents

abrasivesabrasivesabrasivesabrasives

from gettingfrom gettingfrom gettingfrom gettinginto washerinto washerinto washerinto washer




We lose efficiency in the upthrust position because of the

fluid's ability to recirculate from the high pressure to lowpressure eye area. In addition to loss in efficiency, this can

promote erosion in the diffuser in abrasive fluids.




Why use floater pumps?

• Since each stage handles its own thrust, a very large

number of stages can be put in a pump without having to worry about protector bearing capacity.

• Floaters are also very good with mild abrasives since they prevent material from getting into the radialbearing area.

• Floaters are much more forgiving in manufacturingsince tolerance stack-up is not a concern.

• Easier field assembly - no shimming required.

Documents

01 - 1 Pump - Floater vs Compression