Overview of Rotating Equipment Speaker’s name Speaker’s role date John Crane Copyright 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. © John Crane An Overview of Rotating Equipment 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 © John Crane Introductory Exercise Can you already identify the machines listed below as Drivers or Driven Equipment? Driver Driven Compressors Mixers Wind Turbines Hydraulic Motors Fans Steam Turbines Screw Pumps Reciprocating Pumps Diesel Engines Electric Motors © 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). Prime Mover (Driver) Examples of Prime Movers include: Turbines – Steam, Gas, Water & Wind Internal Combustion Engines Electric Motors Rotating Equipment (Driven) Examples of Rotating Equipment include: Centrifugal and Positive Displacement Pumps Compressors Agitators/Mixers/Reactors Electric Generators and Alternators Fans and Blowers © John Crane 1. An Overview of Rotating Equipment 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 © John Crane 2. Prime Movers – Turbomachinery The term turbomachinery describes machines that transfer energy between a rotor and a fluid, including both turbines and compressors. A turbine transfers energy from a fluid to a rotor. A compressor transfers energy from a rotor to a fluid. Typical Steam Turbine Typical Centrifugal Gas Compressor © 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. © 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. © 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 © John Crane 2. Prime Movers – Water Turbines 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 © 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. © 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. © John Crane 2. Prime Movers – Internal Combustion Engines 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. A Hydraulic Motor is a mechanical actuator that converts hydraulic pressure and flow into torque and angular displacement (rotation). Diesel Engines © John Crane 2. Prime Movers – Electric Motors An Electric Motor converts electrical energy into Electric Motors mechanical energy. Most electric motors operate • Direct on line (DOL) through interacting magnetic fields and current• Star Delta carrying conductors to generate force. • Variable speed/variable frequency 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 © John Crane 3. Rotating Equipment (Driven) – Centrifugal Pumps 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 © John Crane 3. Rotating Equipment (Driven) – Positive Displacement Pumps Reciprocating or Hydraulic • • • • Gear Pumps Screw Pumps Piston Pumps Reciprocating Pumps Archimedes' screw pump 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. © John Crane 3. Rotating Equipment (Driven) – Compressors 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. © John Crane 3. Rotating Equipment (Driven) – Compressors 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 R = = © John Crane 3. Rotating Equipment (Driven) – Compressors 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 © John Crane 3. Rotating Equipment (Driven) – Compressors 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: Screw Piston Scroll © John Crane 3. Rotating Equipment (Driven) – Agitators / Mixers / Reactors 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 © John Crane 3. Rotating Equipment (Driven) – Agitators / Mixers / Reactors 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). © John Crane 3. Rotating Equipment (Driven) – Agitators / Mixers / Reactors 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. © John Crane 3. Rotating Equipment (Driven) – Electric Generators & Alternators 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. © John Crane 3. Rotating Equipment (Driven) – Fans & Blowers 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: Extraction Ventilation Cooling Aeration Drying etc. Typical Industrial Fan Power Station Fly Ash Blower © 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. © John Crane 4. Connectors- Modifiers and Couplings The alternative solution is a direct connection between the 2 machines: Prime Mover (Driver) Motor (Driver) Connector Rotating Equipment (Driven) Pump (Driven) © John Crane 4. Connectors – Modifiers and Couplings With a Direct Drive between the driver and the driven equipment, some form of connector device is needed: Prime Mover (Driver) Connector Rotating Equipment (Driven) Modifiers Couplings 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. © 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: Speed Torque Rotational Direction Examples of Modifiers include: Fluid coupling Gearbox Belts Chains © 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. © 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. © 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. © 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. © John Crane 4. Connectors – Modifiers and Couplings The other types of connector devices are known as couplings: Disc Gear Grid Chain Diaphragm Elastomeric Rubber Block Universal Joint Rigid Hose 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. © 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. © John Crane Exercise Can you identify if the Connectors listed below are Modifiers or Couplings? Modifier Coupling Universal Joint Gear Box Belt Drive Chain Pin & Bush Chain Drive Elastomeric Fluid Coupling © John Crane 5. Further Rotating Equipment - Pumps Classification of pumps: 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 © John Crane 5. Further Rotating Equipment - Pumps The Application Data Sheet will usually indicate the ‘Type’ of pump: © 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 © 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 © John Crane 5. Centrifugal Pumps API 610 / ISO 13709 provides a code to classify the various types: © John Crane 5. Centrifugal Pumps – OH1 Centrifugal Pump - Horizontal, overhung, flexibly coupled, foot-mounted (OH1) Semi-open Impeller Seal Chamber © John Crane 5. Centrifugal Pumps – OH1 Seal Chamber Pressure (OH1) 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 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 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 © John Crane 5. Centrifugal Pumps 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: © John Crane 5. Centrifugal Pumps – OH2 Seal Chamber Image: Sulzer Pumps Typical OH2 Process Pump Closed impeller Balance holes Typical pumping applications from petroleum, petrochemical and gas processing industries © John Crane 5. Centrifugal Pumps – OH2 Typical pumping applications include Petroleum, petrochemical and Gas processing industries Image: Flowserve Pumps © John Crane 5. Centrifugal Pumps – OH2 Seal Chamber Pressure for OH2 pumps Strongly influenced by the position of the balance hole in relation to the impeller blade Typically holes in front of the blade Chamber pressure very close to Suction pressure conditions. Suggest the formula (Suction + 10% Differential Pressure) is used 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! © John Crane 5. Centrifugal Pumps – OH2 Horizontal, overhung, flexibly coupled, centreline-mounted – OH2 - 2-stage design Seal chamber pressure = 1st Stage DP + (10% 2nd Stage Differential Pressure) Typical pumping applications include pulp & paper and general applications. Sulzer Ahlstom APP © 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. © John Crane 5. Centrifugal Pumps – OH3 Seal Chamber Pressure as for OH2 Often fitted with Plan 13 which may reduce the pressure even closer to Suction pressure Be careful of 2 stage designs © John Crane 5. Centrifugal Pumps – OH4 Overhung, Vertical, In-Line, Rigidly Coupled Pump (OH4) - Not commonly used Typical pumping applications include flammable liquids, fuel, petroleum, petrochemicals, light oils, hydrocarbon booster, water and general applications. Double Suction impeller Flowserve OH4 Pump © John Crane 5. Centrifugal Pumps – OH5 Overhung, In-Line, Vertical, Close-coupled Pump (OH5) A Shell preference DEP pump © John Crane 5. Centrifugal Pumps – OH5 Overhung, In-Line, Vertical, Close-coupled Pump (OH5) Seal Chamber Pressure as for OH2 Often fitted with Plan 13 which may reduce the pressure even closer to Suction pressure Be careful of 2 stage designs! Seal Chamber Pressure = Suction + (50% Differential Pressure) Flowserve OH5 Pump © John Crane 5. Centrifugal Pumps - Multistage 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: bearings multiple impellers shaft supports (bearings) 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. © John Crane 5. Centrifugal Pumps – Horizontally Split 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. © John Crane 5. Centrifugal Pumps – Horizontally Split Horizontal split casing pumps: Examples of industrial applications for horizontal split casing pumps include: large axially split pumps used on a hydropower project (India) hot water circulation pumps in a district heating system (China) © John Crane 5. Centrifugal Pumps – Axially Split BB1 Between Bearing, single stage, axially split (BB1) Pump 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 © John Crane 5. Centrifugal Pumps – Axially Split BB1 Between Bearing, 2 stage, axially split (BB1) Pump Seal Chamber Chamber Balance Line Seal Chamber Flowserve BB1 2 stage Pump © John Crane 5. Centrifugal Pumps – BB1 Seal Chamber Pressure (2-stage BB1) Seal chamber on Suction end (Drive End) = Suction Pressure Seal chamber on Non-Drive end = Suction + (50% Differential Pressure)? Is a ‘balance line’ connected from the NDE Chamber back to the suction pressure? If so both ends = Suction Pressure Not always done on a 2 stage pump, particularly those without a double suction inlet impeller (already balanced axial thrust)! The existence of a ‘balance line’ is NOT clear from the Pump Data Sheet Recommend always assume NO balance line fitted. i.e. Seal chamber on Second stage end = Suction + (50% Differential Pressure) © John Crane 5. Centrifugal Pumps – Balance Lines Reducing axial thrust across the pump: balance line 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. © John Crane 5. Centrifugal Pumps – Radially Split BB2 Between Bearing, single stage, radially split (BB2) Pump Nearly always supplied with a double suction Seal Chamber Typical pumping applications include hydrocarbon processing. Seal Chamber Sulzer BB2 Pump Seal chamber pressure = Suction pressure © John Crane 5. Centrifugal Pumps – Radially Split BB2 Between Bearing, 2 stage, radially split (BB2) Pump Balance Line Sulzer BB2 2 stage pump Seal chamber pressure = Suction pressure © John Crane 5. Centrifugal Pumps – Radially Split BB2 Between Bearing, 2 stage, radially split (BB2) Pump Face to Face impellers Axial Force balanced No rear wear rings or balance holes Balance Line? Seal Chamber Pressure? 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. © John Crane 5. Centrifugal Pumps – Axially Split BB3 Multistage, axially split Pumps (BB3) 4 stage back-to-back impellers Diffuser Seal Chamber Typical pumping applications include refineries, petrochemicals, pipelines, water injection and power generation applications. Sulzer BB3 Pump © John Crane 5. Centrifugal Pumps – Axially Split BB3 Multistage, axially split Pumps (BB3) 9 stage ‘opposed’ or ‘back-to-back’ impellers Seal chamber pressure = Suction pressure on both ends Discharge Suction Sulzer BB3 Pump Balance Line © John Crane 5. Centrifugal Pumps – Radially Split 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. Typical pumping applications include water booster pumps, boiler feed pumps and building services tie-bolts © John Crane 5. Centrifugal Pumps – Radially Split BB4 Multistage, radially split Pumps, single casing (BB4) Sometimes called ‘Ring Section’ or ‘Segmental Ring’ Pumps Non preferred by API 610/ISO 13709 Seal Chamber pressure = Suction pressure if balance drum used to manage shaft axial thrust 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 © John Crane 5. Centrifugal Pumps – Radially Split BB4 Multistage, radially split Pumps, single casing (BB4) Typical pumping applications include desalination, descaling, water supply / distribution, crude, product and CO2 pipelines, groundwater development / distribution, irrigation and water treatment. Seal chamber pressure (NDE & DE) = Suction pressure Balance Drum Flowserve BB4 8 stage Pump © John Crane 5. Centrifugal Pumps – Radially Split BB4 Multistage, radially split Pumps, single casing (BB4) Typical pumping applications include water supply / distribution, desalination, mining dewatering / supply, groundwater development and irrigation applications. Flowserve BB4 4 stage Pump Balance Disc Seal chamber pressure (DE) = Suction pressure Seal chamber pressure (NDE) = Suction pressure + ?%Pressure © John Crane 5. Centrifugal Pumps – Radially Split BB5 Multistage, radially split Pumps, double casing (BB5) Sometimes referred to as, ‘Barrel Casing’ Pumps Eliminates the potential leak path between each stage segment Typical pumping applications include oil production, refining, and boiler feed applications. Balance Drum Sulzer BB5 Pump © John Crane 5. Centrifugal Pumps – Radially Split BB5 Multistage, radially split Pumps, double casing (BB5) Shaft axial thrust imbalance designs as for single casing BB4 pumps Note the Pump Data Sheet rarely indicates the use of a throat bushing, balance drum or disc Normally suction inlet on DE & Seal Chamber pressure = Suction pressure NDE Seal Chamber pressure with balance drum = Suction pressure NDE Seal Chamber pressure with balance disc = Suction pressure + ?%Differential Pressure 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 Typical pumping applications include sea water injection, produced water injection, main oil lines, condensate export, boiler feed, power plant and refinery applications. © John Crane 5. Centrifugal Pumps – Vertically Suspended VS1 Vertically Suspended, Single Casing, Column Discharge Diffuser design (VS1) ‘Wet Pit’ Pump Flowserve VS1 Pump © John Crane 5. Centrifugal Pumps – Vertically Suspended VS1 Vertically Suspended, Single Casing, Column Discharge - Diffuser design (VS1) Typical pumping Seal Chamber pressure = Discharge applications include pressure 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. Flowserve VS1 Pumps © John Crane 5. Centrifugal Pumps – Vertically Suspended VS2 Vertically Suspended, Single Casing, Column discharge - Volute design (VS2) Limited number of stages Seal Chamber pressure = Discharge pressure 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. Flowserve VS2 Pump © John Crane 5. Centrifugal Pumps – Vertically Suspended VS3 Vertically Suspended, Single Casing, Column discharge - Axial Flow design (VS3) Limited number of stages Seal Chamber pressure = Discharge pressure Typical pumping applications include water treatment, agriculture, power plant cooling water, mine dewatering and supply and groundwater, development / irrigation. Flowserve VS3 Pump © John Crane 5. Centrifugal Pumps – Vertically Suspended VS4 Vertically Suspended, Single Casing, Sump discharge - Line-shaft design (VS4) ‘Sump’ Pump © John Crane 5. Centrifugal Pumps – Vertically Suspended VS5 Vertically Suspended, Single Casing, Sump discharge - Cantilever design (VS5) ‘Sump’ Pump © John Crane 5. Centrifugal Pumps – Vertically Suspended VS4 & VS5 Vertically Suspended, Single Casing, Sump discharge - VS4 & VS5 Liquid level in column same us sump Seal Chamber in air or inert gas in sump 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. © John Crane 5. Centrifugal Pumps – Vertically Suspended VS6 Vertically Suspended, Double Casing Pump - Diffuser design (VS6) Low margin from VP at Suction (low NPSHA) Small footprint Seal Chamber Balance Chamber Typical pumping applications include hydrocarbon booster, transfer pipeline booster, chemical / petrochemical transfer, condensate, brine injection, crude oil loading, condensate extraction and cryogenic services. Balance Drum © John Crane 5. Centrifugal Pumps – Vertically Suspended VS6 Vertically Suspended, Double Casing Pump - Diffuser design (VS6) Shaft in Discharge Line Be careful estimating Seal Chamber pressure! 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 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. © John Crane 6. Positive Displacement Pumps Classifications of positive displacement pumps include: Positive Displacement Pumps Sealless rotary PD Pump designs Rotary Screw Pump Archimedian Screw Pump Screw Pump Progressing Cavity Pump Non-Rotary Gear Pump Internal Gear External Gear Lobe Pump Vane Pump Flexible Vane Pump Sliding Vane Pump Liquid Ring Pump © John Crane 6. Positive Displacement Pumps Seal Chamber Pressure in Rotary Positive Displacement Pumps: Evaluate the pressure conditions at the process entrance to the Seal Chamber Is there a process flush to the seal (Plan 01, 11, 12, 14, 21, 22, 31, 32, 41)? Is there a process flow from the seal chamber (Plan 13, 14)? Is this flow liable to affect the seal chamber pressure? © John Crane 6. Positive Displacement Pumps 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. © John Crane 6. Positive Displacement Pumps Rotary Positive displacement pump: Archimedian Screw Pump Seal Chamber – atmospheric air • Seal required? Typical pumping applications include raw and treated sewage effluent, land drainage and irrigation. Image: math.nyu.edu SeaWorld Adventure Park (San Diego, CA) © John Crane 6. Positive Displacement Pumps Rotary Positive displacement pump: Progressing Cavity Screw Pump Seal Chamber = Suction Pressure • Can be Discharge Pressure if run backwards! Mono Compact C Typical pumping applications include high viscosity lotions / pastes and sewage sludge etc. Seal Chamber © John Crane 6. Positive Displacement Pumps Rotary Positive displacement pump: Screw Pump Seal Chamber – Suction Pressure Warren Imo Screw Pump Typical pumping applications include lubrication oils and clean products. © John Crane 6. Positive Displacement Pumps Rotary Positive displacement pump: Internal Gear Pump Albany HD Gear Pump Typical pumping applications include lubrication oils and clean products. Seal Chamber = [Suction Pressure + (Differential Pressure/2)]?? © John Crane 6. Positive Displacement Pumps Rotary Positive displacement pump: External Gear Pump Seal Chamber Seal Chamber – [Suction Pressure + (Differential Pressure/2)]?? Image: Viking Pump Inc © John Crane 6. Positive Displacement Pumps Rotary Positive displacement pump: Lobe Pump Seal Chamber (2 off) Typical pumping applications include hygienic materials, food production and pharmaceutical applications Inlet Outlet © John Crane 6. Positive Displacement Pumps Rotary Positive displacement pump: Lobe Pump Seal Seal Chamber Seal Chamber Pressure = [Suction Pressure + (80% Differential Pressure)] • Careful of pulsations! © John Crane 6. Positive Displacement Pumps Rotary Positive displacement pump – Flexible & Sliding Vane Pump Seal Chamber – [Suction Pressure + (Differential Pressure/2)]?? Clarksol Flexible Vane Pump Seal Chamber Image: Blackmer Sliding Vane Pump Image: Viking Pump Inc Typical pumping applications include liquids with poor lubricating qualities and food handling applications © John Crane 6. Positive Displacement Pumps Rotary Positive displacement pump: Liquid Ring Vacuum Pumps Graham 2-stage liquid ring vacuum pump © John Crane 6. Positive Displacement Pumps Rotary Positive displacement pump: Liquid Ring Vacuum Pumps Liquid for liquid ring (normally water) continually injected into the impeller cavity and the seal chamber (Plan 32) Injection pressure usually known but sourced from discharge separator Assume seal chamber is discharge pressure 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. © John Crane Exercise Can you answer the questions below? 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? © John Crane 7. Summary / Conclusion There is a huge range of rotating equipment used in process industries, e.g. pumps, compressors, turbines, mixers and fans etc. Rotating equipment operates in different ways to do work to a liquid or gas, transferring energy from the driving to the driven machine The equipment data sheet will identify the equipment type and its design / operating criteria The equipment data sheet can also be used to aid seal selection For effective and reliable performance the sealing solution must integrate with the equipment design © John Crane Further Information Further learning on this topic can be found in the relevant Know-How curriculum: Pump Principles © John Crane