equipos sellos mecanicos

1. © John Crane
Overview of Rotating Equipment
Speaker’s name
Speaker’s role
date
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The information contained in, or attached to, this document, contain confidential information that is proprietary to John Crane.
This document cannot be copied for any purpose, or be disclosed, in part or whole, to third party without the prior approval of John Crane.

2. © John Crane
Session Agenda:
1. An Overview of Rotating Equipment
2. Prime Movers – Drivers
3. Rotating Equipment – Driven
4. Connectors – Modifiers & Couplings
Further Rotating Equipment:
5. Centrifugal Pumps
6. Positive Displacement Pumps
7. Summary and Conclusions
An Overview of Rotating Equipment

3. © John Crane
Introductory Exercise
Driver Driven
Compressors
Mixers
Wind Turbines
Hydraulic Motors
Fans
Steam Turbines
Screw Pumps
Reciprocating Pumps
Diesel Engines
Electric Motors
Can you already identify the machines
listed below as Drivers or Driven Equipment?

4. © John Crane
1. An Overview of Rotating Equipment
In most cases energy is transferred into rotating equipment, from a driving equipment
(known as the Prime Mover) to the driven equipment (known as Rotating Equipment
or the Functional Machine).
Examples of Prime Movers include:
ƒ Turbines – Steam, Gas, Water &
Wind
ƒ Internal Combustion Engines
ƒ Electric Motors
Examples of Rotating Equipment include:
ƒ Centrifugal and Positive Displacement
Pumps
ƒ Compressors
ƒ Agitators/Mixers/Reactors
ƒ Electric Generators and Alternators
ƒ Fans and Blowers
Prime
Mover
(Driver)
Rotating
Equipment
(Driven)

5. © John Crane
Typical rotating equipment fitted with mechanical seals includes:
• centrifugal and positive displacement pumps
• centrifugal gas compressors and refrigeration compressors
• turbines (steam, gas, water, wind)
• agitators / mixers / reactors
• anywhere a rotating shaft passes through a stationary housing where
product has to be contained
1. An Overview of Rotating Equipment

6. © John Crane
The term turbomachinery describes machines that transfer energy between a
rotor and a fluid, including both turbines and compressors.
ƒA turbine transfers energy from a fluid to a rotor.
ƒA compressor transfers energy from a rotor to a fluid.
2. Prime Movers – Turbomachinery
Typical Steam Turbine Typical Centrifugal Gas Compressor

7. © John Crane
2. Prime Movers – Steam Turbines
Steam turbines work on the principle of using pressurised steam to rotate turbine
blades.
This rotation is then used to drive other equipment, in a similar way as an electric
motor but utilising the heat and pressure of the steam rather than electricity as the
driving energy.

8. © John Crane
2. Prime Movers – Gas Turbines
Gas turbines work on the principle of using pressurised fuels to rotate turbine
blades, they can produce a great amount of energy for their footprint size and
weight. Their smaller footprint, low weight and multiple fuel applications make them
the ideal power plant for offshore use.
The rotation is used to drive other equipment, in a similar way as the steam turbine
utilising the heat and pressure of the fuel as the driving energy.
Hot exhaust gases can be used for steam generation, heat transfer, heating and
cooling purposes.

9. © John Crane
2. Prime Movers – Water Turbines
The water turbine converts energy in the form of falling water into rotating shaft
power. The amount of power which can be obtained depends upon the amount of
water available i.e. the flow rate, and the head or fall through which it depends.
The rotating element (`runner') of a reaction turbine is fully immersed in water and
is enclosed in a pressure casing. The runner blades are profiled so that pressure
differences across them impose a lifting force (the wings on an aircraft), which
cause the runner to rotate.
Francis Reaction Turbine Runner Typical Francis Reaction Turbine Typical Kaplan Reaction Turbine

10. © John Crane
An impulse turbine runner operates in air, driven by a jet (or jets) of water. Here the
water remains at atmospheric pressure before and after making contact with the runner
blades.
In this case a nozzle converts the pressurised low velocity water into a high speed
jet. The runner blades deflect the jet so as to maximise the change of momentum of the
water and thus maximising the force on the blades.
Typical Pelton Wheel Turbines Typical Turgo ImpulseTurbine
2. Prime Movers – Water Turbines

11. © John Crane
2. Prime Movers – Water Turbines
This type of water turbine operates in a similar manner as a wind turbine but exploits
underwater currents rather than air, based on the principle that all fluids behave the
same way.

12. © John Crane
2. Prime Movers – Wind Turbines
A Wind turbine is a machine that converts kinetic energy from the wind into
mechanical energy, and this energy can be used to produce electricity e.g. wind
generators / farms, or used to drive other machinery to do useful work e.g. windmills.

13. © John Crane
2. Prime Movers – Internal Combustion Engines
ƒ Reciprocating or Hydraulic
• Diesel / Gas Engines
• Hydraulic Motors
A Reciprocating Engine, also often known
as a piston engine, is a heat engine that
uses one or more reciprocating pistons to
convert pressure into a rotating motion.
Diesel Engines
A Hydraulic Motor is a mechanical
actuator that converts hydraulic pressure
and flow into torque and angular
displacement (rotation).

14. © John Crane
2. Prime Movers – Electric Motors
ƒ Electric Motors
• Direct on line (DOL)
• Star Delta
• Variable speed/variable
frequency
An Electric Motor converts electrical energy into
mechanical energy. Most electric motors operate
through interacting magnetic fields and current-
carrying conductors to generate force.
Electric motors are commonly started Direct On
Line (DOL) where the full line voltage is applied
to the motor terminals. This is the simplest type
of motor starter.
For Softer starts – Star Delta is preferred where
the start is controlled in two phases'
Variable Speed/ Variable Frequency allows full
control of the start up and operation.
Electric Motor

15. © John Crane
3. Rotating Equipment (Driven)
– Centrifugal Pumps
ƒ Centrifugal
• Pumps
• Compressors
• Mixers
• Fans
• Propellers
Centrifugal Driven machines are similar
to a turbine but operating in reverse.
Centrifugal force is defined as moving, or
pulling away from a centre or axis.
Typically a Centrifugal Pump uses a
rotating impeller to increase the pressure
of a fluid.
Centrifugal pumps are commonly used to
move liquids through a piping system.
The fluid enters the pump impeller along or
near to the rotating axis and is accelerated
by the impeller, flowing radially outward
into volute chamber (casing), from where it
exits into the downstream piping system.
Centrifugal Pump

16. © John Crane
3. Rotating Equipment (Driven)
– Positive Displacement Pumps
ƒ Reciprocating
or Hydraulic
• Gear Pumps
• Screw Pumps
• Piston Pumps
• Reciprocating Pumps
All Positive Displacement pumps deliver a constant
amount of fluid for each revolution or stroke.
Gear Pumps use the meshing of gears to pump fluid by
displacement. They are one of the most common types of
pumps for hydraulic fluid power applications. Gear pumps
are also widely used in chemical installations to pump fluid
with a certain viscosity.
Screw Pumps use one or several screws to move fluids
or solids along the screw(s) axis. In its simplest form (the
Archimedes' screw pump), a single screw rotates in a
cylindrical cavity, thereby moving the material along the
screw's spindle.
A Piston Pump is where the high-pressure seal
reciprocates with the piston. Piston pumps can be used to
move liquids or compress gases.
A Reciprocating Pump is a plunger pump. It is often used
where relatively small quantity of liquid is to be handled
and where delivery pressure is quite large.
Archimedes' screw pump

17. © John Crane
A centrifugal gas compressor is a
mechanical devise that increases the
pressure of a gas by reducing its volume.
As with a pump for liquids, a compressor
increases the fluid pressure, and can
transport the fluid through a pipe.
However, as gases are compressible,
the compressor also reduces the gas
volume whereas the main result of a pump
is to increase the pressure of a liquid to
allow it to be transported.
3. Rotating Equipment (Driven)
– Compressors

18. © John Crane
Centrifugal Gas Compressor Construction
Comprises a casing containing rotating shaft,
on which is mounted a cylindrical assembly of
compressor blades.
Each blade on the compressor produces a
pressure variation, similar to an aircraft
propeller airfoil.
Centrifugal compressors also do work on the
flow by rotating (thus accelerating) the flow
radially.
C
C
=
=
R
R
=
=
3. Rotating Equipment (Driven)
– Compressors

19. © John Crane
Centrifugal Gas Compressor Applications
They are used throughout industry because they:
9 have few moving parts
9 are very energy efficient
9 give higher airflow that a similarly sized
reciprocating compressor
3. Rotating Equipment (Driven)
– Compressors

20. © John Crane
Refrigerant Compressors
Designed specifically for air conditioning,
heat pumping and refrigeration applications.
They are integral components of the
refrigeration cycle, in which refrigerant gases
are cyclically evaporated and condensed,
absorbing heat from the load to be cooled, and
delivering it to an open environment where it is
dissipated.
There are 3 main types of refrigerant
compressors:
ƒScrew
ƒPiston
ƒScroll
3. Rotating Equipment (Driven)
– Compressors

21. © John Crane
Agitators / Mixers / Reactors are machines for mixing or agitating a product within
a pressure vessel. They are installed in process plants in industries such as
chemical processing, pharmaceuticals, pulp and paper processing etc.
Applications include:
9 blending
9 dissolving
9 heat transfer
9 solids dispersion
9 solids suspension
9 complete chemical reactions
9 polymerisation
9 crystallisation
9 neutralisation
3. Rotating Equipment (Driven)
– Agitators / Mixers / Reactors

22. © John Crane
Most equipment can be classified into three types of configurations:
Top Entry – the mixer is mounted through an entry port at the top of the vessel.
Bottom Entry – the mixer is mounted through an entry port at the bottom of the
vessel.
Side Entry – the mixer is normally mounted through a nozzle on the side of the
vessel (normally mounted near the bottom of the vessel, to allow mixing at low
liquid levels, and during filling and emptying).
3. Rotating Equipment (Driven)
– Agitators / Mixers / Reactors

23. © John Crane
Most agitators and mixers operate at low
shaft speeds typically around 100 – 500 RPM.
The deflection on a long overhung shaft will
affect the design of the vessel and the sealing
device. They will have to tolerate any run-out
or misalignment due to shaft deflection.
3. Rotating Equipment (Driven)
– Agitators / Mixers / Reactors

24. © John Crane
ƒ Electrical An Electric Generator is a device that
converts mechanical energy to electrical
energy. The reverse conversion of electrical
energy into mechanical energy is done by a
motor; motors and generators have many
similarities.
The source of mechanical energy may be a
reciprocating or turbine steam engine, water
falling through a turbine or waterwheel, an
internal combustion engine, a wind turbine, a
hand crank, compressed air or any other
source of mechanical energy.
An Alternator is an electromechanical device
that converts mechanical energy to electrical
energy in the form of alternating current.
Alternators in power stations driven by steam
turbines are called Turbo-Alternators.
3. Rotating Equipment (Driven)
– Electric Generators & Alternators

25. © John Crane
Industrial fans and blowers consist of shaft mounted rotor blades contained
within a casing, and are used for creating a flow of gas (air).
Fans and blowers have diverse applications in many industries for the following
typical processes:
ƒExtraction
ƒVentilation
ƒCooling
ƒAeration
ƒDrying etc.
Power Station Fly Ash Blower
Typical Industrial Fan
3. Rotating Equipment (Driven)
– Fans & Blowers

26. © John Crane
4. Connectors – Modifiers and Couplings
Whenever two pieces of rotating
machinery such as a pump and a
motor need to be connected
together, there is the possibility of a
direct or indirect connection.
Equipment can be indirectly connected by belts or chains – for example think of a bicycle as
the chain transfers pedal power to the wheel:
However indirectly coupled equipment is usually inefficient, due to frictional losses when the
belts or chains slip during power transmission.

27. © John Crane
4. Connectors- Modifiers and Couplings
The alternative solution is a direct connection between the 2 machines:
Motor (Driver) Pump (Driven)
Prime
Mover
(Driver)
Rotating
Equipment
(Driven)
Connector

28. © John Crane
4. Connectors – Modifiers and Couplings
Modifiers
Couplings
With a Direct Drive between the driver and the driven equipment, some form of
connector device is needed:
The types of driving and driven equipments being driven will affect the choice of the
suitable connector device.
There are various types of connector devices commonly in use in process industries.
Prime
Mover
(Driver)
Rotating
Equipment
(Driven)
Connector

29. © John Crane
4. Connectors – Modifiers and Couplings
Modifiers are connectors and are so described
as they ‘Modify’“ or ‘Change the input to output
transmission properties such as:
ƒ Speed
ƒ Torque
ƒ Rotational Direction
Examples of Modifiers include:
ƒ Fluid coupling
ƒ Gearbox
ƒ Belts
ƒ Chains

30. © John Crane
4. Connectors – Modifiers and Couplings
Modifier
A Fluid Coupling is a hydrodynamic device used to
transmit rotating mechanical power.
It also has widespread application in marine and
industrial machine drives, where variable speed
operation and/or controlled start-up without shock
loading of the power transmission system is essential.

31. © John Crane
4. Connectors – Modifiers and Couplings
Modifier
A Transmission or Gearbox provides speed and torque
conversions from a rotating power source to another
device using gear ratios.

32. © John Crane
4. Connectors – Modifiers and Couplings
Modifier
A Belt is a loop of flexible material used to
link two or more rotating shafts mechanically.
Belts may be used as a source of motion, to
transmit power efficiently.

33. © John Crane
4. Connectors – Modifiers and Couplings
Modifier
A Chain Drive is a way of transmitting mechanical power.
By varying the diameter of the input and output sprockets
with respect to each other, the gear ratio can be altered.

34. © John Crane
4. Connectors – Modifiers and Couplings
ƒ Disc
ƒ Gear
ƒ Grid
ƒ Chain
ƒ Diaphragm
ƒ Elastomeric
ƒ Rubber Block
ƒ Universal Joint
ƒ Rigid
ƒ Hose
ƒ Pin & Bush
All the above connectors transmit torque and
speed without change to the drive characteristics
seen with modifiers.
Couplings can be used in conjunction with
modifiers - they are not in direct competition.
The other types of connector devices are known as couplings:

35. © John Crane
4. Connectors – Modifiers and Couplings
A coupling is a device used to connect two
shafts together at their ends for the
purpose of transmitting torque.

36. © John Crane
Modifier Coupling
Universal Joint
Gear Box
Belt Drive
Chain
Pin & Bush
Chain Drive
Elastomeric
Fluid Coupling
Can you identify if the Connectors listed below
are Modifiers or Couplings?
Exercise

37. © John Crane
Pump types are generally classified according to how they transfer energy to the
fluid, and the combination of pressure and flow which they are designed to
generate:
• pumps which pass kinetic energy to the fluid by means of a rapidly rotating
impeller are known as kinetic or dynamic or centrifugal pumps
• pumps in which the fluid is mechanically displaced are termed positive
displacement pumps
Classification of pumps:
5. Further Rotating Equipment - Pumps

38. © John Crane
The Application Data Sheet will usually indicate the ‘Type’ of pump:
5. Further Rotating Equipment - Pumps

39. © John Crane
5. Further Rotating Equipment - Pumps
A pump data sheet or manufacturer’s rating plate should at least contain the following
information:
• Manufacturer
• Pump serial No
• Pump Direction of Rotation
• Duty Generated Head
• Duty Flowrate
• Pump Absorbed Power at Duty Point
• Pump Running Speed
• Pump Casing Design Pressure

40. © John Crane
5. Further Rotating Equipment - Pumps
The following data relevant to seal selection should also be included:
• Shaft Size
• Pumped Process Fluid (including temperature)
• Barrier Fluid (including temperature)
• Suction Pressure
• Discharge Pressure
• Chamber pressure
• API Piping Plan

41. © John Crane
API 610 / ISO 13709 provides a code to classify the various types:
5. Centrifugal Pumps

42. © John Crane
5. Centrifugal Pumps – OH1
Centrifugal Pump
- Horizontal, overhung,
flexibly coupled, foot-mounted (OH1)
Seal Chamber
Semi-open Impeller

43. © John Crane
5. Centrifugal Pumps – OH1
Seal Chamber Pressure (OH1)
ƒ Influenced by:
• Size of the impeller for a given shaft
• Type of Seal Chamber
1. Traditional cylindrical with throat bushing
2. Cylindrical with open throat
3. Conical or Tapered bore
• Diameter of the seal chamber bore adjacent to back of the impeller
ƒ The radially smaller the back vane ‘sweep’ the lower its effectiveness
• The larger the bore diameter the higher the chamber pressure
• The smaller the impeller size the higher the chamber pressure
ƒ Seal Chamber Pressure = Suction + K x (Differential Pressure) where K is a
relative % value
K = 10% for Chamber type 1
K = 10% to 30% for Chamber type 2 depending on impeller size
K = <= 80% for Chamber type 3 depending on impeller size and bore diameter
adjacent to back of the impeller

44. © John Crane
Many single-stage pumps are known as back pull-out designs, because of the way
that the bearing frame assembly is pulled out from the back of the pump volute:
5. Centrifugal Pumps

45. © John Crane
5. Centrifugal Pumps – OH2
Typical OH2 Process Pump
ƒ Closed impeller
ƒ Balance holes
Image: Sulzer Pumps
Seal Chamber
Typical pumping applications
from petroleum,
petrochemical and gas
processing industries

46. © John Crane
Image: Flowserve Pumps
5. Centrifugal Pumps – OH2
Typical pumping applications include
Petroleum, petrochemical and
Gas processing industries

47. © John Crane
5. Centrifugal Pumps – OH2
Seal Chamber Pressure for OH2 pumps
ƒ Strongly influenced by the position of the balance hole in relation to the impeller
blade
ƒ Typically holes in front of the blade
ƒ Chamber pressure very close to Suction pressure conditions.
Suggest the formula (Suction + 10% Differential Pressure) is used
ƒ Be careful!
• If within the blade curvature this can be below suction pressure.
• Some ‘Circulator’ pumps have no rear wear rings or balance holes. These
pumps typically operate at significant suction pressures and the ‘head’ or
differential pressure is low (2 to 3 bar). Seal chamber is at DP.
• Check if it is 2 stage. In ‘Pump language’, ‘Multistage’ means 3 stages or
more!

48. © John Crane
5. Centrifugal Pumps – OH2
Horizontal, overhung, flexibly coupled, centreline-mounted – OH2
- 2-stage design
Sulzer Ahlstom APP
Seal chamber pressure =
1st Stage DP + (10% 2nd Stage
Differential Pressure)
Typical pumping
applications include pulp
& paper and general
applications.

49. © John Crane
5. Centrifugal Pumps – OH3
Overhung, Vertical, In-Line, bearing frame Pump (OH3)
Sulzer OHV Pump
Typical pumping applications include
refineries, oil & gas production, pipeline
boosting and offshore applications.

50. © John Crane
5. Centrifugal Pumps – OH3
ƒ Seal Chamber Pressure as for OH2
ƒ Often fitted with Plan 13 which may
reduce the pressure even closer to
Suction pressure
ƒ Be careful of 2 stage designs

51. © John Crane
5. Centrifugal Pumps – OH4
Overhung, Vertical, In-Line, Rigidly Coupled Pump (OH4)
- Not commonly used
Flowserve OH4 Pump
Double Suction impeller
Typical pumping
applications include
flammable liquids,
fuel, petroleum,
petrochemicals,
light oils, hydrocarbon
booster, water and
general applications.

52. © John Crane
5. Centrifugal Pumps – OH5
Overhung, In-Line, Vertical, Close-coupled Pump (OH5)
A Shell preference DEP pump

53. © John Crane
5. Centrifugal Pumps – OH5
Overhung, In-Line, Vertical, Close-coupled Pump (OH5)
ƒ Seal Chamber Pressure as for OH2
ƒ Often fitted with Plan 13 which may reduce the pressure even closer to Suction
pressure
ƒ Be careful of 2 stage designs!
Flowserve OH5 Pump
Seal Chamber Pressure
= Suction + (50% Differential Pressure)

54. © John Crane
Multistage pumps - a ‘between bearings’ configuration:
A multistage pump is an example of a between bearings design, where the shaft
and impellers are supported on 2 sets of bearings, one at either end of the pump:
This is in contrast to an overhung design commonly used on many single-stage pumps,
where the shaft and impeller are supported on only one side, and overhang as a
cantilever. However with multiple impellers a shaft support is needed at both ends.
The 2 ends of a multistage pump are generally referred to as the drive end DE (i.e. the
motor & coupling end of the shaft) and the non-drive end NDE respectively.
bearings multiple impellers
shaft supports (bearings)
5. Centrifugal Pumps - Multistage

55. © John Crane
Horizontal split casing pumps:
Horizontal split casing pumps are versatile designs, found in a wide
variety of applications such as:
• water supply schemes
• irrigation
• industrial water supply
• oil refineries
• chemical and fertilizer plants
• electricity boards
• mining etc.
5. Centrifugal Pumps – Horizontally Split

56. © John Crane
Horizontal split casing pumps:
large axially split pumps used
on a hydropower project
(India)
hot water circulation pumps in a
district heating system
(China)
Examples of industrial applications for horizontal split casing pumps include:
5. Centrifugal Pumps – Horizontally Split

57. © John Crane
Between Bearing, single stage, axially split (BB1) Pump
ƒ Nearly always supplied with a double suction (low NPSH with high Q)
Seal Chamber
Seal Chamber
Seal chamber pressure = Suction
pressure
Flowserve BB1 single stage Pump
5. Centrifugal Pumps – Axially Split BB1

58. © John Crane
Between Bearing, 2 stage, axially split (BB1) Pump
Flowserve BB1 2 stage Pump
Chamber Balance Line
Seal Chamber
Seal
Chamber
5. Centrifugal Pumps – Axially Split BB1

59. © John Crane
Seal Chamber Pressure (2-stage BB1)
ƒ Seal chamber on Suction end (Drive End) = Suction Pressure
ƒ Seal chamber on Non-Drive end = Suction + (50% Differential Pressure)?
ƒ Is a ‘balance line’ connected from the NDE Chamber back to the suction
pressure? If so both ends = Suction Pressure
ƒ Not always done on a 2 stage pump, particularly those without a double suction
inlet impeller (already balanced axial thrust)!
ƒ The existence of a ‘balance line’ is NOT clear from the Pump Data Sheet
ƒ Recommend always assume NO balance line fitted. i.e.
Seal chamber on Second stage end = Suction + (50% Differential Pressure)
5. Centrifugal Pumps – BB1

60. © John Crane
Reducing axial thrust across the pump:
Balance line:
Another way of equalising pressure and balancing
axial loading across the pump casing is to use a
balance line. This type of design is also used in
multi-stage pumps.
The balance line consists of an external pipe,
connecting the high (discharge) side of the pump
back to the low (suction) side.
balance line
5. Centrifugal Pumps – Balance Lines

61. © John Crane
Between Bearing, single stage, radially split (BB2) Pump
ƒ Nearly always supplied with a double suction
Seal
Chamber
Seal
Chamber
Sulzer BB2 Pump
Seal chamber pressure
= Suction pressure
5. Centrifugal Pumps – Radially Split BB2
Typical pumping
applications include
hydrocarbon
processing.

62. © John Crane
Between Bearing, 2 stage, radially split (BB2) Pump
Balance Line
Seal chamber pressure
= Suction pressure
Sulzer BB2 2 stage pump
5. Centrifugal Pumps – Radially Split BB2

63. © John Crane
Between Bearing, 2 stage, radially split (BB2) Pump
ƒ Face to Face impellers
ƒ Axial Force balanced
ƒ No rear wear rings or
balance holes
ƒ Balance Line?
ƒ Seal Chamber Pressure?
ƒ Be very careful of BB1 &
BB2 seal chamber
pressure predictions
Flowserve BB2 2 stage Pump
Typical pumping applications include heavy
oil, boiler feed, oil / shale sands, hydraulic
press (metal), hydrocracking, hydrotreating,
acid transfer, industrial gases, catalytic
cracking, caustic and chor-alkali.
5. Centrifugal Pumps – Radially Split BB2

64. © John Crane
Multistage, axially split Pumps (BB3)
ƒ 4 stage back-to-back impellers
Sulzer BB3 Pump
Diffuser
Seal Chamber
5. Centrifugal Pumps – Axially Split BB3
Typical pumping applications
include refineries, petro-
chemicals, pipelines, water
injection and power generation
applications.

65. © John Crane
Multistage, axially split Pumps (BB3)
ƒ 9 stage ‘opposed’ or ‘back-to-back’ impellers
ƒ Seal chamber pressure = Suction pressure on both ends
Sulzer BB3 Pump Balance Line
Suction
Discharge
5. Centrifugal Pumps – Axially Split BB3

66. © John Crane
Radially split / stage casing pumps:
Some pump designs have the pump body radially
split (vertically split) into individual stages. Each
stage is fitted with a diffuser guiding the flow into
the next stage, thereby increasing the pressure by
the head generated in each individual impeller.
These designs are sometimes also known as stage
casing pumps.
Pumps of this design normally have a very robust
construction, for use on high pressure services. The
pump casings are held together by tie-bolts, and all
impellers are dynamically balanced.
tie-bolts
5. Centrifugal Pumps – Radially Split
Typical pumping applications include
water booster pumps, boiler feed
pumps and building services

67. © John Crane
Multistage, radially split Pumps, single casing (BB4)
ƒ Sometimes called ‘Ring Section’ or ‘Segmental Ring’ Pumps
ƒ Non preferred by API 610/ISO 13709
ƒ Seal Chamber pressure = Suction pressure if balance drum used to manage shaft
axial thrust
ƒ Be careful if design uses a balance disc to manage shaft axial thrust
• Suction end seal chamber = Suction pressure
• Other end seal chamber = Suction pressure + ?% Differential Pressure
5. Centrifugal Pumps – Radially Split BB4

68. © John Crane
Multistage, radially split Pumps, single casing (BB4)
Balance Drum
Seal chamber pressure (NDE & DE) = Suction
pressure
Flowserve BB4 8 stage Pump
Typical pumping applications
include desalination,
descaling, water supply /
distribution, crude, product
and CO2 pipelines, ground-
water development /
distribution, irrigation and
water treatment.
5. Centrifugal Pumps – Radially Split BB4

69. © John Crane
Multistage, radially split Pumps, single casing (BB4)
Flowserve BB4 4 stage Pump
Balance Disc
Seal chamber pressure (DE) = Suction pressure
Seal chamber pressure (NDE) = Suction pressure
+ ?%Pressure
Typical pumping applications
include water supply /
distribution, desalination, mining
dewatering / supply,
groundwater development
and irrigation applications.
5. Centrifugal Pumps – Radially Split BB4

70. © John Crane
Multistage, radially split Pumps, double casing (BB5)
ƒ Sometimes referred to as, ‘Barrel Casing’ Pumps
ƒ Eliminates the potential leak path between each stage segment
Balance Drum
Sulzer BB5 Pump
Typical pumping applications
include oil production, refining,
and boiler feed applications.
5. Centrifugal Pumps – Radially Split BB5

71. © John Crane
ƒ Shaft axial thrust imbalance designs as for single
casing BB4 pumps
ƒ Note the Pump Data Sheet rarely indicates the use
of a throat bushing, balance drum or disc
ƒ Normally suction inlet on DE & Seal Chamber
pressure = Suction pressure
ƒ NDE Seal Chamber pressure with balance drum =
Suction pressure
ƒ NDE Seal Chamber pressure with balance disc =
Suction pressure + ?%Differential Pressure
ƒ Wear of drum and disc increases NDE Seal
Chamber pressure; discuss with OEM the
tolerance range.
• Applies to both BB4 and BB5. Weir FK BB5 Pump
Multistage, radially split Pumps, double casing (BB5)
Typical pumping applications include sea water injection,
produced water injection, main oil lines, condensate
export, boiler feed, power plant and refinery applications.
5. Centrifugal Pumps – Radially Split BB5

72. © John Crane
Vertically Suspended, Single Casing, Column Discharge
ƒ Diffuser design (VS1)
ƒ ‘Wet Pit’ Pump
Flowserve VS1 Pump
5. Centrifugal Pumps
– Vertically Suspended VS1

73. © John Crane
Vertically Suspended, Single Casing, Column Discharge
- Diffuser design (VS1)
ƒ Seal Chamber pressure = Discharge
pressure
Flowserve VS1 Pumps
Typical pumping
applications include
chemical / petrochemical,
liquefied gas pipeline /
transfer service, offshore
crude oil loading,
lubricating oil,
condensate extraction,
seawater lift,
stormwater / drainwater
services, recovered oil,
and tank services.
5. Centrifugal Pumps
– Vertically Suspended VS1

74. © John Crane
Vertically Suspended, Single Casing, Column discharge
- Volute design (VS2)
ƒ Limited number of stages
ƒ Seal Chamber pressure = Discharge pressure
Flowserve VS2 Pump
Typical pumping applications include raw water intake,
freshwater supply / distribution, irrigation, fire protection,
condensate extraction, heater drainage, transfer, loading
and unloading, steel mill cooling and quench services,
mine dewatering and acid leaching, brine recirculation
and MSF desalination blowdown.
5. Centrifugal Pumps
– Vertically Suspended VS2

75. © John Crane
Vertically Suspended, Single Casing, Column discharge
- Axial Flow design (VS3)
ƒ Limited number of stages
ƒ Seal Chamber pressure = Discharge pressure
Flowserve VS3 Pump
Typical pumping applications include
water treatment, agriculture, power
plant cooling water, mine dewatering
and supply and groundwater,
development / irrigation.
5. Centrifugal Pumps
– Vertically Suspended VS3

76. © John Crane
Vertically Suspended, Single Casing, Sump discharge
- Line-shaft design (VS4)
ƒ ‘Sump’ Pump
5. Centrifugal Pumps
– Vertically Suspended VS4

77. © John Crane
Vertically Suspended, Single Casing, Sump discharge
- Cantilever design (VS5)
ƒ ‘Sump’ Pump
5. Centrifugal Pumps
– Vertically Suspended VS5

78. © John Crane
Vertically Suspended, Single Casing, Sump discharge
- VS4 & VS5
ƒ Liquid level in column same us sump
ƒ Seal Chamber in air or inert gas in sump
ƒ Seal Chamber at Atmospheric pressure
Typical pumping applications include flood
control, groundwater development/irrigation,
water supply/treatment for oil and gas, molten
salt transfer, waste water treatment, heavy oil
and oil sands and shale.
5. Centrifugal Pumps
– Vertically Suspended VS4 & VS5

79. © John Crane
Vertically Suspended, Double Casing Pump
- Diffuser design (VS6)
ƒ Low margin from VP at Suction (low NPSHA)
ƒ Small footprint
Balance
Chamber
Seal Chamber
Balance
Drum
Typical pumping
applications include
hydrocarbon booster,
transfer pipeline
booster, chemical /
petrochemical
transfer, condensate,
brine injection, crude
oil loading,
condensate
extraction and
cryogenic services.
5. Centrifugal Pumps
– Vertically Suspended VS6

80. © John Crane
Vertically Suspended, Double Casing Pump
- Diffuser design (VS6)
ƒ Shaft in Discharge Line
ƒ Be careful estimating Seal Chamber pressure!
ƒ Seal chamber at Discharge Pressure (Plan13)
Or alternatively:
• ‘Leak-off’ design from throat bushing to
lower Seal Chamber pressure
• Balance drum design
• Seal Chamber at Suction pressure
• Plan 11 or 14
ƒ No clarity of design in Pump Data Sheet
Typical pumping
applications include
cryogenic applications
handling such
chemicals as
ammonia, ethylene,
propylene, LPG / LNG,
methane and butane.
5. Centrifugal Pumps
– Vertically Suspended VS6

81. © John Crane
Positive Displacement Pumps
Gear Pump
Internal
Gear
External
Gear
Screw Pump
Screw
Pump
Archimedian
Screw Pump
Progressing
Cavity Pump
Vane Pump
Flexible
Vane Pump
Sliding
Vane Pump
Liquid Ring
Pump
Lobe Pump
Rotary Non-Rotary
Sealless rotary PD
Pump designs
6. Positive Displacement Pumps
Classifications of positive displacement pumps include:

82. © John Crane
Seal Chamber Pressure in Rotary Positive Displacement Pumps:
ƒ Evaluate the pressure conditions at the process entrance to the Seal Chamber
ƒ Is there a process flush to the seal (Plan 01, 11, 12, 14, 21, 22, 31, 32, 41)?
ƒ Is there a process flow from the seal chamber (Plan 13, 14)?
ƒ Is this flow liable to affect the seal chamber pressure?
6. Positive Displacement Pumps

83. © John Crane
A positive displacement pump has a cavity or cavities which are alternately filled
and emptied by the pump action, causing fluid to move in a forward-only fashion.
There is an expanding cavity on the suction side of the pump, and a decreasing
cavity on the discharge side.
Liquid is allowed to flow into the pump as the cavity on the suction side expands,
and the liquid is then forced out of the discharge as the cavity collapses.
Positive displacement pumps all operate on similar working principles, but are
generally classified into reciprocating and rotary designs. Types of positive
displacement pump design include:
• rotary lobe
• gear within a gear
• reciprocating piston
• screw
• progressive cavity etc.
Unlike a centrifugal pump, a positive displacement pump will produce the same
flow at a given speed, no matter what the discharge pressure is.
6. Positive Displacement Pumps

84. © John Crane
Rotary Positive displacement pump: Archimedian Screw Pump
Seal Chamber – atmospheric air
• Seal required?
Image: math.nyu.edu
SeaWorld Adventure Park (San Diego, CA)
Typical pumping applications
include raw and treated sewage
effluent, land drainage and
irrigation.
6. Positive Displacement Pumps

85. © John Crane
Rotary Positive displacement pump: Progressing Cavity Screw Pump
Mono Compact C
Seal Chamber
Seal Chamber = Suction Pressure
• Can be Discharge Pressure if run
backwards!
Typical pumping
applications include high
viscosity lotions / pastes
and sewage sludge etc.
6. Positive Displacement Pumps

86. © John Crane
Rotary Positive displacement pump: Screw Pump
Seal Chamber – Suction Pressure
Warren Imo Screw Pump
Typical pumping applications include lubrication oils and clean products.
6. Positive Displacement Pumps

87. © John Crane
Rotary Positive displacement pump: Internal Gear Pump
Albany HD Gear
Pump
Seal Chamber
= [Suction Pressure + (Differential
Pressure/2)]??
Typical pumping applications include
lubrication oils and clean products.
6. Positive Displacement Pumps

88. © John Crane
Rotary Positive displacement pump: External Gear Pump
Seal Chamber
Seal Chamber
– [Suction Pressure + (Differential
Pressure/2)]??
Image: Viking Pump Inc
6. Positive Displacement Pumps

89. © John Crane
Rotary Positive displacement pump: Lobe Pump
Outlet
Outlet
Inlet
Inlet
Seal Chamber (2 off)
Typical pumping
applications include
hygienic materials,
food production
and pharmaceutical
applications
6. Positive Displacement Pumps

90. © John Crane
Seal
Seal
Chamber
Seal Chamber Pressure
= [Suction Pressure + (80%
Differential Pressure)]
• Careful of pulsations!
6. Positive Displacement Pumps
Rotary Positive displacement pump: Lobe Pump

91. © John Crane
Rotary Positive displacement pump
– Flexible & Sliding Vane Pump
Image: Viking Pump Inc
Clarksol Flexible Vane Pump
Seal Chamber
– [Suction Pressure +
(Differential Pressure/2)]??
Image: Blackmer Sliding Vane Pump
Seal Chamber
Typical pumping
applications include
liquids with poor
lubricating qualities and
food handling
applications
6. Positive Displacement Pumps

92. © John Crane
Rotary Positive displacement pump: Liquid Ring Vacuum Pumps
Graham 2-stage liquid ring vacuum pump
6. Positive Displacement Pumps

93. © John Crane
ƒ Liquid for liquid ring (normally water) continually injected into the impeller cavity
and the seal chamber (Plan 32)
ƒ Injection pressure usually known but sourced from discharge separator
ƒ Assume seal chamber is discharge pressure
ƒ Statically the chamber may be full vacuum
Typical pumping applications include
forming pulp & paper products, e.g. egg
boxes / packaging, petroleum refining,
e.g. vacuum distillation.
6. Positive Displacement Pumps
Rotary Positive displacement pump: Liquid Ring Vacuum Pumps

94. © John Crane
True False
Fluid is mechanically displaced in a Kinetic or dynamic pump?
An impeller will impart kinetic energy to a fluid?
Centrifugal pump types are classified in API 610/ISO 13709?
Impellers can be classed as open, semi-open and closed?
A sliding vane pump is a type of dynamic pump?
Progressing cavity pumps can be run in reverse?
A screw pump is ideal for pumping raw sewage?
A positive displacement pump will produce the same flow at a
given speed, no matter what the discharge pressure is?
Can you answer the questions below?
Exercise

95. © John Crane
ƒ There is a huge range of rotating equipment used in process industries,
e.g. pumps, compressors, turbines, mixers and fans etc.
ƒ Rotating equipment operates in different ways to do work to a liquid or gas,
transferring energy from the driving to the driven machine
ƒ The equipment data sheet will identify the equipment type and its design / operating
criteria
ƒ The equipment data sheet can also be used to aid seal selection
ƒ For effective and reliable performance the sealing solution must integrate with the
equipment design
7. Summary / Conclusion

96. © John Crane
Further Information
Further learning on this topic can be found in the relevant Know-How curriculum:
Pump Principles