TWIN SCREW PUMPS - Насосное оборудование для всех ... · 2016-11-25 ·...

3P Prinz Pump Manufacturing Company

TWIN SCREW PUMPS

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Lucca, 15 June 2016


TABLE OF CONTENT

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1) INTRODUCTION TO THEORY OF TWIN SCREW PUMPS

2) FEATURES AND ADVANTAGES

3) BASIC EXECUTIONS

4) APPLICATION FIELDS

5) 3P PRINZ TWIN SCREW PUMP RANGE

6) 3P PRINZ MODEL DE-CODIFICATION

7) MATERIALS SELECTION

8) SIZING OF TWIN SCREW PUMPS

9) FLUIDS HANDLED

10) NPSHr AND SUCTION LIFT

11) PUMP EXECUTIONS FOR THE MAIN SECTORS

12) CRITICAL APPLICATIONS

13) PERFORMANCE TEST STANDARDS

14) API 676 COMPLIANCE AND DEVIATIONS

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The PERA-PRINZ® Screw Pumps are Rotating Positive Displacement Pumps, externally or

internally supported.

One or Two Pairs of Screws, which operate without being in contact with each other,

ensure a constant flow, pulsation-free, together with a high suction lift capability with

very low NPSH values.

Horizontal Installation is supplied as standard while Vertical Installation is supplied on

request.

External supports and gears is supplied as Standard while Internal supports and gears

can be supplied on request, in case the pumped fluid is sufficiently clean and lubricating.

PERA-PRINZ® TWIN SCREW PUMPS

SINGLE AND DOUBLE END POSITIVE DISPLACEMENT PUMPS

Series HM – HR – HD – UD – JD – SR – SD

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The Screws Pair rotates inside the Pump Enclosure, creating several separate chambers and pushing the fluid

trapped inside in accordance with the progression of the screws pitch.

The flow rate is particularly uniform and pulsation-free, and the pumped fluid flows in an axial direction (not

circumferentially, as it happens in the centrifugal pumps).

Fluids that are sensitive to shear forces or turbulent flows are subject only to very limited stresses during the

pumping phase:

Thanks to the absence of pulsations, to the low flow internal velocities, to the minimization of the centrifugal

movements and to the absence of contact between the screw rotors, the pumped product does not suffer of

changes of volume, texture, aspect and properties.

Thanks to the low inertia of the rotating parts, the Screw Pumps can

work at rotating speeds higher than other Positive Displacement Pumps

of equivalent volume chambers.

PERA-PRINZ® TWIN SCREW PUMPS WORKING PRINCIPLE

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Timing Gears

PERA-PRINZ® TWIN SCREW PUMPS WORKING PRINCIPLE

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2 Opposite Screws mounted on 1 Shaft

Bearings


BY APPLICABLE STANDARD:

• Manufacturer Standard

• API 676

PERA-PRINZ® TWIN SCREW PUMPS EXECUTIONS

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• The Radial and Axial Loads are balanced on the Double Volute Twin Screw Pumps.

• Only the Radial Loads are balanced on the Single Volute Twin Screw Pumps.

BY MOUNTING:

• Overhung Twin Screws

/ Single Volute (Single End)

/ Single Pair of Screws

• Between Bearing Twin Screws

/ Double Volute (Double End)

/ Double Pair of Screws


BY INSTALLATION:

• Horizontal Shaft (Side – Top Flanges)

• Vertical Shaft (Side – Side Flanges)

• Horizontal Shaft (Side – Side Flanges)


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BY LINER:

• Non-Replaceable Liner

- Cast Body

• Replaceable Liner

– Welded Fabricated Steel Body


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• Self Priming

• They ensure a constant flow, pulsation-free

• High Suction Lift Capability – the pump NPSH being very low

• Suitable to pump fluids with low, medium, high and very high viscosity.

Very well suited to pump very viscous liquids, sensitive to shear forces and turbulences thanks to the low Internal

velocities given by the screws movement.

• Low Noise Level and Low Vibrations

• The Screws are Contactless and Wear out is minimized

PERA-PRINZ® TWIN SCREW PUMPS ADVANTAGES

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PERA-PRINZ® TWIN SCREW PUMPS ADVANTAGES ON TANK STORAGE

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CENTRIFUGAL PUMPS FOR TANK STORAGE:

- Capable of pumping fluids only up to approximately 150 cSt

- Generate pressure in accordance to their characteristic Curve

- Not well suitable to variable speed operation

TANK STORAGE

PRODUCTS OFFLOADING

BB1 Centrifugal Pump:

1500 m3/h @ 100 mwc

Max 150 cSt

CRUDE OIL CARRIER

BB1 Centrifugal Pump:

800 m3/h @ 100 mwc

Max 150 cSt

OIL TANK BARGE

OH1 Centrifugal Pump:

150 m3/h @ 100 mwc

Max 150 cSt

OIL TRUCK - RAILCAR

PUMP 1

PUMP 3

PUMP 2


PERA-PRINZ® TWIN SCREW PUMPS ADVANTAGES ON TANK STORAGE

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TWIN SCREW PUMPS FOR TANK STORAGE:

• Capable of Operating at High Angular Speeds thanks to the screws low inertia, allowing a high range of flow rates if

the pumps are driven by a Variable Speed Drive or by an Inverter

• Constant Flow regardless pressure changes (in particular when viscous fluids are pumped)

• Capability of handling a Wide Range of viscosities and pressures

TANK STORAGE

PRODUCTS OFFLOADING

1500 m3/h @ 100 mwc

Max 500 cSt

CRUDE OIL CARRIER

800 m3/h @ 100 mwc

Max 1000 cSt

OIL TANK BARGE

150 m3/h @ 100 mwc

Max 2000 cSt

OIL TRUCK - RAILCARONE PUMP FOR ALL SERVICES

ONLY ONE INSTALLATION:

Less installation costs

Less pipe work


• Flow can be reversed (reversibility) in low pressure applications, upon request

• Entrapped Air or Gas in the Liquid are tolerated up to 50-60% volume (multi-phase service on request)

• Capability of Dry Running for a limited period and in particular conditions

• Compact Design and Dimensions

PERA-PRINZ® TWIN SCREW PUMPS ADVANTAGES

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• CAPACITY: from 1 m3/h up to 3.500 m3/h [from 4.5 GPM up to 15,500 GPM]

• CASING PRESSURE: up to ANSI 900 - 149 barg [2160 Psig]

• DIFFERENTIAL PRESSURE: up to 60 bar [870 Psi]

• NPSHr: down to 1,5 meters [5 ft]

• VISCOSITIES: from 0,5 cSt up to 50.000 cSt (up to 250.000 cSt in special execution)

• PUMP NOISE LEVEL: up to 85 dB for small and medium sizes

• GAS/AIR HANDLING: Gas/Air Content up to 50% (dissolved, not slug)

• TEMPERATURE: up to 300°C [573°F]


GENERAL FEATURES AND PERFORMANCES

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PERA-PRINZ® TWIN SCREW PUMPS MAIN APPLICATIONS

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FLUIDS HANDLED:

- CRUDE OIL (RAW OR REFINED)

- CRUDE OIL MIXED WITH WATER

- CRUDE OIL MIXED WITH WATER AND GAS

- ALL TYPE OF HYDROCARBONS, LIGHT AND HIGH VISCOSITY (FROM GASOLINE TO BITUMEN)

- OIL / WATER EMULSIONS, INCLUDING SLOPS, PRODUCED WATER

- CHEMICALS (METHANOL, INHIBITORS)

OIL FIELDS

OFFSHORE PLATFORMS

FPSOs & FSOs

OIL & GAS

UPSTREAM



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FLUIDS HANDLED:

- CRUDE OIL (RAW OR REFINED)

- CRUDE OIL MIXED WITH WATER

- CRUDE OIL MIXED WITH WATER AND GAS

- ALL TYPE OF HYDROCARBONS, LIGHT AND HIGH VISCOSITY (FROM GASOLINE TO BITUMEN)

- OIL / WATER EMULSIONS, INCLUDING SLOPS, PRODUCED WATER

- CHEMICALS (METHANOL, INHIBITORS)

OIL PIPELINE

OIL TANKER / BARGE

REFINERY

PETROCHEMICAL PLANTS

TANK STORAGE TERMINALS

OIL & GAS

MIDSTREAM

DOWNSTREAM



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FLUIDS HANDLED:

- CRUDE OIL

- ALL TYPE OF HYDROCARBONS, LIGHT AND HIGH VISCOSITY:

- GASOLINE

- DIESEL / NAPHTA

- LUBE OIL

- HEAVY FUEL OIL / MAZOUT

- BITUMEN / ASPHALT / TAR

- OIL / WATER EMULSIONS, INCLUDING SLOPS

- TANK STRIPPING FOR ALL FLUIDS

OIL TANKERS

BARGES

CARRIERS

CRUISE SHIPS

NAVY SHIPS

SUPPORT VESSELS

MARINE &

SHIPBUILDING



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OTHER APPLICATION FIELDS

Power Plants Light and Heavy Liquid Fuels Fuel Burner Oils Lube Oil

Food & Beverage and Pharmaceutical

Dairy Products (Yogurt, Cream) Fruit Juices, Pastes, Jam Syrups and Molasses

Vegetable and Animal Oils / Fats Pastes Processed Meat

Alcohol / Liquors Chocolate Caramel and Fudge

Sauces / Concentrates Dough Beer and Wines

Chemical Industry

Acids and Concentrated Acids Solvents Lubricating Oils

Aliphatic Acids Additives Wax

Glycerin Latex Lye

Glues Alkaline Solutions Emulsions

Soaps Caustic Soda Solvents

Liquid Sulfur Rubber Suspensions Paraffin

Polymers / Fibers Suspensions Polyester Resins

General IndustryColouring & Pigmented Pastes Thickeners Additives

Enamels and Paints Emulsions Hydraulics


PERA-PRINZ® TWIN SCREW PUMPS SERIES

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TWIN SCREW PUMP CAPACITY RANGE DESIGN PRESSURE MARKET

HM Series

Single Pair of Screws,

External Timing Gears up to 80 m3/h 20 Bar Oil&Gas, Industrial, Marine

HR Series

Double Pair of Screws, Light & Compact Design,


HD Series

Double Pair of Screws, Heavy Duty Design,


UD Series

Double Pair of Screws, High Pressure Design,


JD Series

Double Pair of Screws, Very High Pressure Design,

External Timing Gears up to 600 m3/h 100 Bar Oil&Gas, Industrial

SD Series


Internal Timing Gears up to 1200 m3/h 25 Bar Oil&Gas, Industrial, Marine

SR Series

Double Pair of Screws, Light & Compact Design,

Internal Timing Gears up to 1200 m3/h 14 Bar Oil&Gas, Industrial, Marine

VDC Series


Vertical Submerged,

Internal Timing Gears up to 1000 m3/h 50 Bar Oil&Gas, Marine


PERA-PRINZ® TWIN SCREW PUMPS COVERAGE CHART

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0

500

1000

1500

2000

2500

3000

3500

0 10 20 30 40 50 60 70

Ca

pa

cit

y(m

3/h

)

Differential pressure(bar)

Twin screw pump coverage chart

3P Prinz Pump Manufacturing Company21

Pump type TWIN SCREW PUMPS – EXTERNAL TIMING GEARS

Pump Series HR Series: HRV Series

Installation Options: Horizontal Vertical

Executions:Standard & API 676 with deviations - Timing Gears - External Gears and

Bearings

Optimized for Applications in: Petrochemical, Chemical, Shipbuilding, General Industry, Oil&Gas

Suitable to Fluid having the following properties:

Abrasive and not Abrasive

Corrosive (Alkaline / Acid / Aggressive) and not Corrosive

Low / Medium / High / Very High Viscosities

Not Lubricating or Lubricating

Medium / High percentage of Gas or Air dissolved in Liquid

Slightly Dirty (small soft particles)

Pump Series HR Series:

Maximum design pressure: 14 bar (standard) [204 psig]Flow rates: up to 3500 m3/h [15400 GPM]Viscosity of the pumped fluid: up to 35.000 cSt

Pipe Nominal Size DN: from 50 to 750 [from 2’’ up to 30’’]Rotation speed: from 200 up to 2200 rpm

Temperature range: -46 / +300 °C [-51 / +572 °F]Pulsations: Minimized (almost zero)

Bearing types: External Bearings and Gears in oil bath / grease


Pump type TWIN SCREW PUMPS - EXTERNAL TIMING GEARS

Pump Series HD Series: HDL Series: HDV Series

Installation Options:Horizontal (Cast Casing)

Horizontal (Fabricated Steel Casing, with ReplaceableLiner) Vertical

Executions: Standard & API 676 - Timing Gears - External Gears and Bearings

Optimized for Applications in: Oil&Gas, Petrochemical, Chemical, Shipbuilding, General Industry






Medium / High percentage of Gas or Air dissolved in Liquid (Multiphase versions available)

Slightly Dirty (small particles)

Pump Series HD Series:

Maximum design pressure: 20 bar (standard) [300 psig]Flow rates: up to 3500 m3/h [15400 psig]Viscosity of the pumped fluid: up to 35.000 cSt

Pipe Nominal Size DN: from 50 to 750 [from 2’’ up to 30’’]Rotation speed: from 200 up to 2200 rpm


Bearing types: External Bearings and Gears in oil bath


Pera Prinz® - Comparison between HR and HD Series

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Pera Prinz® - Some HD Series pumps dimensions

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Pump type TWIN SCREW PUMPS - EXTERNAL TIMING GEARS

Pump Series UD Series:UDL Series &JDL Series

UDV Series &JDV Series:

Installation Options:Horizontal (Cast Casing)

Horizontal (Fabricated Steel Casing, with ReplaceableLiner) Vertical


Optimized for Applications in: Oil&Gas, Petrochemical, Chemical, Shipbuilding








Pump Series UD Series: JD Series_

Maximum design pressure: 50 barg [730 psig]149 barg [2170 psig]max ANSI 900 rating

Flow rates: up to 1000 m3/h [4000 GPM] up to 600 m3/h [2650 GPM]Viscosity of the pumped fluid: up to 35.000 cSt up to 35.000 cSt

Pipe Nominal Size DN: from 50 to 400 – from 2’’ to 16’’ from 50 to 400 – from 2’’ to 14’’

Rotation speed: from 200 up to 2200 rpm from 200 up to 2200 rpm

Temperature range: -46 / +350 °C [-51 / +662 °F] -46 / +350 °C [-51 / +662 °F]Pulsations: Minimized (almost zero) Minimized (almost zero)

Bearing types: External Bearings and Gears in oil bath External Bearings and Gears in oil bath


SD Series: High Capacity Double End Twin Screw Pump

– Internal Gears and Bearings (Wetted and cooled by the Pumped Fluid);

Maximum Pressure 16 barg [232 psig] ;

Higher Pressures Executions available on request;

Suitable only to Clean and Lubricating Fluids (no Abrasive Particles)

SD-V Series: Vertical Installation Version of SD Series

SR Series: High Capacity Double End Twin Screw Pump

– Internal Gears and Bearings (Wetted and cooled by the Pumped Fluid);

Maximum Pressure 14 barg [204 psig] ;

Suitable only to Clean and Lubricating Fluids (no Abrasive Particles)

SR-V Series: Vertical Installation Version of SR Series

Pump type TWIN SCREW PUMPS - INTERNAL TIMING GEARS


Pump type VERTICAL TWIN SCREW PUMPS - INTERNAL TIMING GEARS

Pump Series VDC Series:

Installation Options: Vertical - Submerged


Optimized for Applications in: Oil&Gas, Petrochemical, Shipbuilding








Pump Series VDC Series:

Maximum design pressure: 50 barg [730 psig]Flow rates: up to 600 m3/h [2650 GPM]Viscosity of the pumped fluid: up to 35.000 cSt

Pipe Nominal Size DN: from 50 to 400 – from 2’’ to 16’’

Rotation speed: from 200 up to 2200 rpm


Bearing types: Bearings and Gears wetted by Pumped Fluid


Pump typeSCREW PUMPS - TIMING EXTERNAL GEARS

OVERHUNG SCREWS – SINGLE VOLUTE

Pump Series HM Series: HM-V Series:

Installation Options: Horizontal Vertical


Optimized for Applications in:

Oil&Gas, Petrochemical, Chemical, Shipbuilding, Power Generation, General Industry




Low / Medium / High Viscosities


Medium percentage of Gas or Air dissolved in Liquid


Pump Series HM Series:

Maximum design pressure: 20 bar (standard)

Flow rates: up to 80 m3/h [353 GPM]Viscosity of the pumped fluid: up to 35.000 cSt

Pipe Nominal Size DN: from 40 to 100 [from 1.1/2’’ to 4’’]Rotation speed: from 200 up to 3600 rpm


Bearing types: External Bearings and Gears in oil bath


PERA-PRINZ® TWIN SCREW PUMPS – HM250


PERA-PRINZ® TWIN SCREW PUMPS – HM200 VERTICAL (OFFSHORE / MARINE)


PERA-PRINZ® TWIN SCREW PUMPS WITH ELECTRIC MOTOR – HD PUMPS WITH DRAIN

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PERA-PRINZ® TWIN SCREW PUMPS WITH ELECTRIC MOTOR – HD PUMPS WITHOUT DRAIN

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PERA-PRINZ® TWIN SCREW PUMPS WITH ELECTRIC MOTOR – HM PUMPS

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PERA-PRINZ® TWIN SCREW PUMPS MODEL DE-CODIFICATION:

HD, HR, UD, JD, SD, SR Series

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HD 0 12 G2 C2 0 T01 NZ

PUMP SERIES:HD, HR, UD, JD, SD, SR

PUMP SIZE MODEL:

HD, UD, JD, SD:06, 07, 10, 12, 14, 17, 20, 22, 25, 30

HR, SR:09, 14, 18, 23, 30, 37, 50

MATERIAL OF BODY

MATERIAL OF SCREWS + SHAFTS

LINERMATERIAL

TYPE OF MECHANICAL SEAL:T01: component typeT02: single, cartridge API 682T03: double, cartridge API 682T04: single cartridge, not APIT0B: Packing type sealOthers: please contact 3P Prinz

ACCESSORIES / OPTIONS

PUMP EXECUTION:0 (no liner)L (with liner)V (vertical)


PERA-PRINZ® TWIN SCREW PUMPS MODEL DE-CODIFICATION:

HM Series

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HM 050 G2 C2 T01 NZ Z

PUMP SERIES:HM

PUMP SIZE MODEL:

HM: 050, 100, 200, 250, 300

MATERIAL OF BODY

MATERIAL OF SCREWS + SHAFTS

TYPE OF MECHANICAL SEAL:T01: component typeT02: single, cartridge API 682T03: double, cartridge API 682T04: single cartridge, not APIT0B: Packing type sealOthers: please contact 3P Prinz

ACCESSORIES / OPTIONS

PUMP EXECUTION:Z (no liner)V (vertical)


PERA-PRINZ® TWIN SCREW PUMPS MAIN MATERIALS USED

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MATERIALS DESCRIPTION MATERIAL INTERNATIONAL CODE

Cast Iron GG25 (G25)

Ductile Cast Iron GJS-400 (GGG400)

Carbon Steel (Casting) ASTM A216 WCB

Carbon Steel (Fabricated) ASTM A105 / ASTM A516 Gr.60

Carbon Steel (Barstock / Forging) ASTM A105

Low Temperature Carbon Steel (Casting) ASTM A352 LCB

Low Temp. Carbon Steel (Barstock/Forging) ASTM A350 LF2

Nickel-Aluminium Bronze ASTM B148 type

Stainless Steel 12% (Cast) CA6NM

Stainless Steel 12% (Barstock/Generic) AISI 420

Stainless Steel 316 grade (Cast) ASTM A351 CF8M (1.4408)

Stainless Steel 316L grade (Cast) ASTM A351 CF3M (1.4404)

Stainless Steel 316/316L grade (Barstock) ASTM A479 or A276 316 or 316L

Stainless Steel 17-4PH grade (Barstock) ASTM A564 630 or commonly 17-4PH (1.4542)

Stainless Steel 431 grade (Barstock) AISI 431 (1.4057)

Duplex stainless steel 22% Cr (Cast) ASTM A890 Grade 4A or A995 Gr.4A (1.4462)

Duplex stainless steel 22% Cr (Barstock) ASTM A479 F51 / UNS S31803 (1.4462)

OTHER MATERIALS: PLEASE CONTACT 3P PRINZ


PERA-PRINZ® TWIN SCREW PUMPS MAIN MATERIALS COMBINATIONS

HD, UD, JD, SD Series

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REFINED HYDROCARBON PRODUCTS (not corrosive, low water content):

GASOLINE, DIESEL, NAPHTA, MAZOUT, HEAVY FUEL OIL, LUBE OIL

Casing Material Screws Material Shafts Material Stuffing Box Material

GG25 GJS-400 or AISI 4140 AISI 4140 A105 / A516 Gr.60

GJS-400 GJS-400 or AISI 4140 AISI 4140 A105 / A516 Gr.60

BITUMEN, TAR (WITH HEATING JACKET)


Fabricated Carbon Steel

+ GG25 Liner AISI 4140 AISI 4140 A105 / A516 Gr.60


+ GG25 Liner AISI 431 or AISI 420 17-4PH A105 / A516 Gr.60

SWEET CRUDE OILCasing Material Screws Material Shafts Material Stuffing Box Material

ASTM A216 WCB

(GG25 or GJS-400 when allowed) AISI 4140 AISI 4140 A105 / A516 Gr.60


+ GG25 Liner AISI 431 or AISI 420 17-4PH A105 / A516 Gr.60




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SOUR CRUDE OIL


ASTM A216 WCB,

NACE MR-0175 AISI 420 or AISI 316 17-4PH A105 / A516 Gr.60


+ A216 WCB Liner , NACE MR-0175

AISI 431 or

Duplex 22% Cr 17-4PH A105 / A516 Gr.60

AISI 316/316L (Cast or Fabricated) Duplex 22% Cr Duplex 22% Cr AISI 316 / 316L

Duplex 22% Cr (Cast)

Duplex 22% Cr or

Superduplex 25%Cr

Duplex 22% Cr or

Superduplex 25%Cr Duplex 22% Cr

CHEMICALS


AISI 316/316L (Cast or Fabricated)

AISI 316/316L

or AISI 431 or 17-4PH 17-4PH AISI 316 / 316L

Bearing Housing and Timing Gear Housing: Cast Iron or Fabricated Steel




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CHEMICALS


AISI 316/316L (Cast or Fabricated)

AISI 316/316L

or AISI 431 or 17-4PH 17-4PH AISI 316 / 316L

HYDROCARBONS WITH SEAWATER CONTENT / SEAWATER (Example: Slops)


GG25 or GJS-400 Duplex 22% Cr 17-4PH A105 / A516 Gr.60

Nickel-Alum Bronze Duplex 22% Cr Duplex 22% Cr AISI 316 / 316L

Super Duplex 25% Cr

(Cast) Super Duplex 25%Cr Super Duplex 25%Cr Super Duplex 25% Cr

Bearing Housing and Timing Gear Housing:

Cast Iron or Fabricated Steel



HR, SR Series

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REFINED HYDROCARBON PRODUCTS (not corrosive, low water content):

GASOLINE, DIESEL, NAPHTA, MAZOUT, HEAVY FUEL OIL, LUBE OIL

Casing Material Screws Material Shafts Material

Stuffing Box Material (including Bearing

Housing and Timing Gear Housing)

GG25 GJS-400 or AISI 4140 17-4PH A105 / A516 Gr.60

GJS-400 GJS-400 or AISI 4140 17-4PH A105 / A516 Gr.60

SWEET CRUDE OIL




GG25 AISI 4140 17-4PH A105 / A516 Gr.60

GJS-400 AISI 4140 17-4PH A105 / A516 Gr.60

HYDROCARBONS WITH SEAWATER CONTENT / SEAWATER (Example: Slops)




GG25 Duplex 22% Cr 17-4PH A105 / A516 Gr.60

GJS-400 Duplex 22% Cr 17-4PH A105 / A516 Gr.60


PERA-PRINZ® TWIN SCREW PUMPS – INFLUENCE OF VISCOSITY

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LOW VISCOSITY FLUIDS EFFECTS:

- Backflow (Slippage) increases

- Volumetric Efficiency decreases

- Less friction losses / Higher Mechanical Efficiency

- Speed should be increased up to 1450 - 1800 rpm (or even more)

- It is not recommended to run the pump at low speeds with low viscosities (limited differential

pressures and capacity)

LOWER DIFFERENTIAL PRESSURE LIMITATION

LOWER CAPACITY



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HIGH VISCOSITY FLUIDS EFFECTS:

- Backflow (Slippage) decreases

- Volumetric Efficiency increases

- Higher friction losses / Lower Mechanical Efficiency

- Speed should be decreased to low speed in order to fill up the chambers without formation of

vacuum in the suction

- It is not recommended to run the pump at high speeds with high viscosities (risk of malfunctioning

of the pump because of vacuum in the suction)

HIGHER DIFFERENTIAL PRESSURE POSSIBLE

HIGHER CAPACITY



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FLUIDS BEHAVIOUR:

- NEWTONIAN FLUIDS: Viscosity is not influenced by the shear force

Viscosity remains constant when the fluid flows through the pump

- NON-NEWTONIAN FLUIDS: Viscosity is influenced by the shear force (time dependent viscosity

Viscosity drops if higher shear is applied when fluid flows through the pump

FLUID TEXTURE MAY CHANGE AFTER SHEAR IS APPLIED



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SHEAR SENSITIVE FLUIDS:

- SOME NON-NEWTONIAN FLUIDS

- EMULSIONS (water+oil, water+oil+air)

TWIN SCREW PUMPS HANDLE THE FLUID WITH A LOW SHEAR :

- The main part of the fluid is pumped with an axial movement (not centrifugal, not turbulent), without

acceleration and with low shear

- The small part of the fluid that back flows

through the gaps between screws

and liner is pumped with higher shear

HIGH SHEAR / TURBULENCE CAUSES FOAM


CENTRIFUGAL PUMPS OR OTHER HIGH SHEAR PUMPS (example Gear Pumps)

HIGH SHEAR / TURBULENCE CAUSES FOAM

when oil/water emulsions are pumped;

Light hydrocarbons may become gas

when depressurized

TWIN SCREW PUMPS AVOID THE FORMATION OF FOAM AND INCREASE PRODUCTIVITY

Foam decreases productivity

and may cause downtimes

Production Costs increase


PERA-PRINZ® TWIN SCREW PUMPS – GAS HANDLING

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Twin Screw Pumps can handle a reasonable percentage of Gas dissolved in the liquid

Depending on the application, they can handle up to 50% of Gas!

An analysis of the application shall be executed in order to confirm suitability:

- Type of application (Upstream or Downstream)

- Availability of all the Process Parameters

- How the Gas is mixed in the Fluid: Dissolved? Gas Bubbles? Gas Slugs?

MULTIPHASE PUMPS


PERA-PRINZ® TWIN SCREW PUMPS – HANDLING SAND PARTICLES

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Twin Screw Pumps can handle a small quantity of sand dissolved in the liquid.

It is important to know the Sand Particle Size Distribution.

The Sand Particles will increase wear on the screws / liner.

The pump performance may lower due to increased clearance

that increases backflow.

It is not possible to predict the wear out caused by sand particles, but some actions can be taken

during offer and design stage:

Examples: - Hardening of Screws and Liner (including Tungsten Carbide Overlay)

- Replaceable Liners

- Increased clearances between screw/screw and screws/liner


PERA-PRINZ® TWIN SCREW PUMPS – HANDLING SAND PARTICLES

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WORST CONDITIONS FOR PUMPING SAND PARTICLES:

- Fluid Viscosity is Low

- High Pump RPMs

- Higher Differential Pressures

- Percentages of Solid Particles higher than 0,01% in volume

Pumping low viscosity liquid with sand particles at high speeds increases sensitively the abrasion

effect

PUMP PERFORMANCES MAY DECREASE QUICKLY

Frequent maintenance and spare parts replacement

It is important to select the right pump execution and materials


PERA-PRINZ® TWIN SCREW PUMPS – SELF PRIMING – DRY RUNNING

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SELF PRIMING

Twin Screw Pumps are Self Priming if the internal chamber is wet

(slightly filled with fluid)

DRY RUNNING

Twin Screw Pumps, thanks to the non-contacting screws, can run dry

Standard mechanical seals will heat up quickly during dry running:

- Select proper facing materials of the mechanical seals

- For longer dry running periods, select quenching on double mechanical seals

Twin Screw Pumps (except FMH hygienic pumps, that are self-draining) are designed

to retain some liquid inside the pumping chamber


PERA-PRINZ® TWIN SCREW PUMPS – SUCTION & NPSH

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Twin Screw Pumps have high suction lift and low NPSHr pumps.

Generally, Centrifugal Pumps have worse suction lift.

If the Fluid Pressure in a major cavity of the pump drops down the vapor pressure, then the liquid will

vapourize (formation of vapor/gas bubbles in the liquid).

The Fluid enters the Pump Suction Flange and, because of frictions and hydraulic effects (changes

of flow, turbulences etc.), the hydrostatic pressure of the fluid drops down.



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SUCTION LIFT PERFORMANCES DEPEND ON:

- PUMP CONSTRUCTION: Geometry of the Chamber and Suction Port

- FLUID VAPOUR PRESSURE: fluids with high vapour pressure need pumps with Lower NPSHr in order to

avoid cavitation

- PUMP SPEED: Higher Speed = Higher Vacuum on Suction = Higher NPSHr

- PUMP CAPACITY: Higher Capacity on the same pump = Higher Hydraulic Losses = Higher NPSHr



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CAVITATION

If the Pressure in any part of the Pump Chamber falls below the Fluid Vapour Pressure, the Fluid will

vapourize (formation of bubbles of gas/vapour inside the liquid).

The implosions are so strong that they can damage the

wetted metallic surfaces of the pumps and create a

particular erosion effect.

The effects of Cavitation may destroy a pump quickly

Cavitation will directly decrese the Pump Performances

On other part inside or downstream of the pump, because of the pumping effect, the fluid pressure will be

over the Vapour Pressure again, and the gas bubble will implode suddenly and become liquid again.

This implosion is very fast and a multitude of collapsing bubbles generates a noise similar to «Cracking»

«Small stones passing inside the piping»



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EFFECTS OF CAVITATION

CENTRIFUGAL PUMPS



54

NPSHr = Net Positive Suction Head required

This is the difference between the Pressure at the Suction Flange of the Pump and the Fluid Vapour

Pressure

This is the Minimum Head required by the pump, calculated at the Suction Flange, in order to avoid

Cavitation at a certain Flow Rate and with a certain Fluid.

In order to avoid Cavitation, NPSHa must be higher than NPSHr:

NPSHa = Net Positive Suction Head available

NPSHa > NPSHr



55

How to improve (=increase) NPSHa:

Reduction of Friction Losses and Hydraulic Losses:

- Larger Diameter Piping

- Reduction of Piping Elbows

- Smoother rugosity values of the Piping

- Less Valves (or Full Bore Valves)

- Reduction of the Velocity of the Fluid and avoidance of Turbulent Flow

- Avoid changes of diameter of the Piping

- Position of the Pump below the suction tank (example, in an underground Pit)



56

- Select a pump with low NPSHr (for example, a Twin Screw Pump)

- Select an optimal geometry of the Pump Suction

- Run the pump at the optimal speed (=not too fast speeds)

- Select a pump slightly oversized for the required flow rate

How to improve (= lower) NPSHr:

Very good realistic values of NPSHr are around 1,5 meters



57

Typical Suction Head Curve:

When the capacity loss is

higher than 3%, then it is

assumed that Cavitation has

started

Gas entrained in the liquid

(bubbles) will be degassed:

The Performance Loss is

smoother than in the

Cavitation effect


PERA-PRINZ® TWIN SCREW PUMPS – PUMP EXECUTIONS FOR HIGH TEMPERATURES

58

- Cooling of the Timing Gearbox and of the

Bearing Housing may be required

- It is recommended to use a longer shaft for

better cooling on the ends

- Cast Casing Pumps with Heating Jacket

- Fabricated Steel Pumps with Welded Heating Jacket

- Pumps with Electric Tracing Coils


PERA-PRINZ® TWIN SCREW PUMPS – SHAFT DEFLECTION

59

It is important to assure high stiffness / rigidity of the shaft costruction, in order to minimize the

deflection

- Short Width and

Compact Pump

- Short Distance between the

Bearings

- High Elastic Module Materials

(high rigidity)

- Less deflection means smaller

clearance between screws

and liner


PERA-PRINZ® TWIN SCREW PUMPS – SPEED VARIATION

60

Twin Screw Pumps are often operated by motors at fixed speed.

The usage of a Speed Variation Device (for example Variable Frequency Drive) can give some advantages

like:

- Change of Capacity

- Possibility of pumping a wide range of viscosities

- Soft / Smooth Start-Up and Cold Starts

- Improvement of Suction Capability (for example during Stripping)


PERA-PRINZ® TWIN SCREW PUMPS – PUMP INSTRUMENTATION

61

Twin Screw Pumps can be mounted, on request, with the following accessories:

- Temperature Sensors / Transmitters on Pump Bearings and / or Casing

- Vibration Sensors on Pump Supports

- Valves and Piping

- API PLAN Seal Panels

- Pressure Sensors / Transmitters on Pump Suction and / or Discharge Ports

- Bearing / Gear Boxes Cooling Systems (by water or by air/oil), with natural and

forced re-circulation

- Dry Running Protection (Oil Pot)

- All Motor Options and Executions in accordance to major Suppliers


PERA-PRINZ® TWIN SCREW PUMPS – MARINE & SHIPBUILDING

62

Twin Screw Pumps for Marine & Shipbuilding:

- Vertical Executions: More common because of space saving;

different executions can be offered;

Non Submerged Versions and Submerged Versions available

- Horizontal Executions (example some Cargo Loading/Unloading, Slops)

The following Class Certification and Inspections are available



63

VERTICAL EXECUTIONS

Submerged Vertical

Twin Screw Pump

supported by mounting

stool

Submerged Vertical

Twin Screw Pump with

Double Cardanic Shaft

Vertical Twin Screw

Pump, not submerged



64

PUMP WITH BULKHEAD:

The pump is in an hazardous area

The motor is in a safe area;



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Applications for Twin Screw Pumps for MARINE AND SHIPBUILDING:

- Engine Room Pumps

- Cargo Pumps

- Stripping and ballast water Pumps

- Bitumen tanker Pump

- Slops

- Stripping of Tank

ADVANTAGES:

- Ideal for pumping low and high viscosity products and oil&water mixes


PERA-PRINZ® TWIN SCREW PUMPS – TANK STORAGE

66

Applications for Twin Screw Pumps for TANK STORAGE:

- Pumping high or low viscosity products

- Loading / Unloading with high or low capacity

- Pumping at high or low pressure

- Pumping at high or low pressure

- Circulation from Tank to Tank

- Stripping of Tank

ADVANTAGES:

- Installation of 1 inlet pipe (reduced installation costs)

- Easier operation and higher safety due to variable operation



67

3 SCREW PUMPS UNDER DEVELOPMENT

THREE SCREW PUMP CAPACITY RANGE

DESIGN

PRESSURE MARKET

MT Series Universal Mid-Pressure Three Screw Pump 50 m3/h 25 Bar Oil&Gas, Industrial, Marine


PERA-PRINZ® TWIN SCREW PUMPS – CRITICAL APPLICATIONS

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PROBLEM SOLUTION

Sand Particles Content Replaceable Liner, Hard Coatings

Corrosive Elements

( Salt / H2S and Sulfides / Chlorides) NACE material, Duplex, Superduplex

Gas Content Mech Seals + API PLAN or Multiphase

Toxic Fluids Double Mech Seals + API PLAN 52, 53, 54

Wax, Paraffin Mech seals heating / cold start issues

Hydrocarbons, Aromatic Hydrocarbons Proper Elastomer Material

High Temperatures (example Bitumen, Tar) Heating Jacket, Longer Shaft, cooled gears



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PROBLEM SOLUTION

Dry Running Double Seals with Quench, Oil Pot with Sensor

Low NPSHa Right pump selection, optimize speed

High Discharge Pressure Increase Casing Design Pressure (UD, JD)

High Differential Pressure Longer Shafts, Increase Gap with Liner

Low Environment Temperature Low Temp Materials and Lubrication

High Environment Temperature Sunshades, Gearbox Cooling, Derated Motor

High Elevation (Altitude) Motor derating



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PROBLEM SOLUTION

API 676 requirements

Separate Relief Valve, Special Materials,

API 682 Seals, API Baseplate

ATEX requirements (Zone 0? Zone 1? Zone 2?) ATEX motor, ATEX Pump

Other Hazardous Area Requirements (UL/FM, CSA) Suitable Motor certification

Multi Pump Skid Package

Clarify the Operational Requirements

and Scope of Supply (Piping, Valves, Sensors, Inverter, PLC)


PERA-PRINZ® TWIN SCREW PUMPS – PUMP TESTING

71

Our Twin Screw Pumps are 100% tested.

Minimum Testing Standards:

- Casing Hydrostatic Test: 1.5 times the casing design pressure for 10 minutes

- Performance Test at Rated Conditions or at Re-calculated Conditions with Test Fluid Viscosity –

Standard VDMA 24 284

- Functional Running Test (no load) for checking Accessories Functionality (when included)

Other Testing Standards:

On request, we can perform tests in accordance to the major Standards



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VDMA 24 284 Standard

Permissible deviations for the capacity

According to the Standard VDMA 24284, the reading of the capacity value performed with the

instrument may deviate from the contract value according to the following values:

Q (l/h) ≤100 +20% / -10%

100≤ Q (l/h) ≥1000 ±10%

Q (l/h)>1000 +10% / -5%



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VDMA 24 284 Standard

Permissible deviations for the power

According to the Standard VDMA 24284, Table 5, Group 2, the reading of the power value performed

with the instrument may deviate from the contract value according to the following values:

P (kW) ≤5 +25%

5≤ P (kW) ≥10 +20%

10≤ P (kW) ≥50 +15%

P (kW)>50 +10%



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API 676 Standard

- Permissible deviations for the Capacity:

Tolerance at 100% speed : +3% / -0%

- Permissible deviations for the Power:

Tolerance at rated pressure + capacity: +4%

- Permissible deviations for the NPSHr:

Tolerance at rated capacity: +0%


PERA-PRINZ® TWIN SCREW PUMPS – API 676 STANDARD

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Our Twin Screw Pumps can comply with API 676 Standard (2nd and 3rd edition) on request

Some of the most important design conditions requested by API 676:

- Relief Valve shall be external (we generally supply it «loose»)

- Baseplate shall be provided with lifting lugs, earthing bosses, levelling screws;

it shall be suitable for grouting,

it shall extend below the drive train components and accessories,

and drain pipe shall extend up to baseplate edge

- Mechanical seals shall be API 682, with suitable API PLAN as applicable



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MAIN EXCEPTIONS / DEVIATIONS POSSIBLE FROM API 676 3RD ED.

PARA 6.9.4 (Last Sentence)

Depending on the interaxis lenght between the 2 axis, there may not be sufficient space to assemble 2

API 682 Cartridge Seals;

API 676 accepts that Cartridge type seals should be used when not unpractical:

“NOTE: Space or design parameters for some pump types, sizes, or applications make the use of API

682/ISO 21049 seals impractical”

SO THIS IS AN ACCEPTABLE DEVIATION FOR SMALL SIZE PUMPS (HD06, HD07, HR09, HR14)



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PARA 6.8.2.1

Timing Gears of the Twin Screw Pump will be designed as per ISO Standards, not as per AGMA

Standard.

PARA 6.8.1.9

Rotors for twin screw pumps shall be dynamically balanced to ISO 1940-1 Grade 2.5.

We generally propose Grade 16 in order to avoid costly calibration or more expensive double profile

screws.



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PARA 6.12.9 and 6.12.10

Pressure lubrication system for Timing Gear Box and Bearing Housing is not generally to API 614,

unless explicitally required (because of the major price impact)

PARA 6.1.1.

Uniterrupted years of operation does not generally exceed 2 years (instead of the 3 years required)

because of Mechanical Seals Service Life



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PARA 7.5.1 and 7.5.2

Pressure Limiting Valves (Relief Valves), in downstream applications, may be supplied not fully as per

API 520 and 526 standards.

PARA 6.13.2.1.

API 676 requires that «Unless otherwise specified, the materials of construction of the pressure-

containing casing shall be carbon steel as a minimum».

When technically possible, we propose as alternative Cast Iron Casing, unless Carbon Steel is

specifically required on the Data Sheets.



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PARA 8.3.6

Test Tolerances proposed are in accordance with VDMA 24 284 Table 5 group 2.

PARA 8.2.2.1.1

Radiographies are not offered, in case Purchaser request for them.

As alternative, we propose other NDE tests.



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END

TWIN SCREW PUMPS - Насосное оборудование для всех ... · 2016-11-25 ·...

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Transcript of TWIN SCREW PUMPS - Насосное оборудование для всех ... · 2016-11-25 ·...