PUMPS TECHNOLOGY2

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PUMPS TECHNOLOGY:

5/7/2011 1 PUMPS TECHNOLOGY GENERAL COURSE FOR ENGINEERS For more PPT presentations: http://www.y-ebooks.com

INTRODUCTION:

5/7/2011 2 INTRODUCTION PUMPS DEFINATION PUMPS HISTORY PUMPS APPLICATIONS PUMPS TERMINOLGY

MAIN TOPICS :

5/7/2011 3 MAIN TOPICS PUMPS CLASSIFICATION PUMPS APPLICATION MAJOR COMPONENTS OF CENERIFUGAL & RECIPROCATING PUMPS CALCULATION & PERFORMANCE OPERATION & TROUBLESHOOTING

PUMPS:

5/7/2011 4 PUMPS Pumps are machines that are used to move liquids from one place to anther through pipelines. Pumps handle all kinds of liquids. Pumping rates can vary from a few gallons to a million/day

:

5/7/2011 5 Pumps are made of different materials in different sizes and shapes Pumps are the second common machine in the world Pumps are used in all power plant

Pumps applications:

5/7/2011 6 Pumps applications Examples of pumps application in power plants: Boiler circulation Feed water Fuel oil Chemical Feed Condensate Circulation water Vacuum

THEORY OF PUMPS:

5/7/2011 7 THEORY OF PUMPS Pump Head Static Suction Lift Static Section Head Total Static Head Static Discharge Head Cavitations Net Positive Suction Head

A) Pump Heads:

5/7/2011 8 A) Pump Heads Hss & Hsd : represent the pressure heads at suction and discharge ports of the pump if the flow rate is zero Hss= h1+Pa/y Hsd= h2+Pb/y Hst=hsd - hss Pb Pa h1 h2 S D DATEM LINE p

PUMPS TERMES:

5/7/2011 9 PUMPS TERMES Fig. a Suction Lift – Showing Static Heads in a Pumping System Where the Pump is Located Above the Suction Tank. (Static Suction Head)

PUMPS TERMS:

5/7/2011 10 PUMPS TERMS Fig. b Suction Head – Showing Static Heads in a Pumping System Where the Pump is Located Below the Suction Tank. (Static Suction Head)

Suction Head:

5/7/2011 11 Suction Head Suction Head A Suction Head exists when the liquid is taken from an open to atmosphere tank where the liquid level is above the centerline of the pump suction, commonly known as a Flooded Suction.

Suction Lift:

5/7/2011 12 Suction Lift Suction Lift exists when the liquid is taken from an open to atmosphere tank where the liquid level is below the centerline of the pump suction

Pump Heads:

5/7/2011 13 Pump Heads Pump suction head (hs) Hs represents the pressure head at the pump suction nozzle Hs= Pa/y+h1-v2/2g-hLs hL=f(L/D)v2/2g F=friction factor D=diameter V=velocity L= length of pipe up to the point required Pa h1 P hs S D EGL HGL

Pump Heads:

5/7/2011 14 Pump Heads Pump delivery head (hd) The pump delivery head represents the pressure head at the pump discharge nozzle (d) Hd= Pb/y+h2-v2/2g+hLd p S D h2 b

Head Total Dynamic :

5/7/2011 15 Head Total Dynamic Total Dynamic Head (TDH) = Elevation (ft) + Friction (ft)

Atmospheric Pressure :

5/7/2011 16 Atmospheric Pressure The Pressure of the Atmosphere on the Earth Atmospheric Pressure at Sea Level

Absolute Pressure:

5/7/2011 17 Absolute Pressure Absolute Pressure is the sum of the available atmospheric pressure and the gage pressure in the pumping system Absolute Pressure (PSIA) = Gauge Pressure + Atmospheric Pressure Absolute Pressure = 150 PSIG (Gauge Pressure) + 14.7 PSI (Atmospheric Pressure) = 164.7 PSIA

Pump capacity:

5/7/2011 18 Pump capacity Capacity (Q) is normally expressed in gallons per minute (gpm). Since liquids are essentially incompressible, there is a direct relationship between the capacity in a pipe and the velocity of flow. This relationship is as follows: Q=A*V Where A = area of pipe or conduit in square feet. V = velocity of flow in feet per second.

PUMPS CLASSIFICATION:

5/7/2011 19 PUMPS CLASSIFICATION Dynamic pump Displacement

CENTRIFUGAL CLASSIFICATION:

5/7/2011 20 CENTRIFUGAL CLASSIFICATION

Slide 21:

5/7/2011 21 Centrifugal Pumps are classified into three general categories: CENTRIFUGAL PUMPS RADIAL FLOW MIXED FLOW AXIAL FLOW

Slide 22:

5/7/2011 22 Axial Flow - a centrifugal pump in which the pressure is developed by the propelling or lifting action of the vanes of the impeller on the liquid. Radial Flow - a centrifugal pump in which the pressure is developed wholly by centrifugal force. Mixed Flow - a centrifugal pump in which the pressure is developed partly by centrifugal force and partly by the lift of the vanes of the impeller on the liquid.

CENTERIFUGAL PUMP:

5/7/2011 23 CENTERIFUGAL PUMP OPERATE ON THE PRINCIPLE OF CENTERIFUGAL FORCE DRIVEN BY ELECTRIC MOTOR STEAM TURBINE GAS TURBINE

Axial Flow:

5/7/2011 24 Axial Flow

Radial Flow Types:

5/7/2011 25 Radial Flow Types The flow parallel to the axis (the center line) of the shaft

AXIAL FLOW:

5/7/2011 26 AXIAL FLOW Axial flow pumps are propeller pump The arrangement of the pump is usually vertical Ability to operate at high speed Lift capacity, discharge and the head are low There are to type: single stage & multistage

RADIAL FLOW:

5/7/2011 27 RADIAL FLOW Flow at 9 0 angle to the center line of the shaft

MIXED FLOW:

5/7/2011 28 MIXED FLOW Mixed flow pump is a pump that uses both axial-flow and radial flow components in one impeller The head developed by centrifugal force and partly by the lift of the impeller vanes on the liquid Is used mainly on low head high capacity.

MAJOR COMPONENTS OF CENTERIFUGAL PUMP:

5/7/2011 29 MAJOR COMPONENTS OF CENTERIFUGAL PUMP SUCTION INLET IMPELLER SHAFT CASING(HOUSING) DISCHARGE OUTLET BEARINGS SEALS

Centrifugal Pump Components:

5/7/2011 30 Centrifugal Pump Components The two main components of a centrifugal pump are the impeller and the volute . The impeller produces liquid velocity and the volute forces the liquid to discharge from the pump converting velocity to pressure.

CENTRIFUGAL PUMP:

5/7/2011 31 CENTRIFUGAL PUMP

CENTERIFUGAL PUMPS:

5/7/2011 32 CENTERIFUGAL PUMPS

SUCTION INLET:

5/7/2011 33 SUCTION INLET Liquid enter the pump through the suction The side of flow entering is called UPSTREAM The discharge side is called the DOWNSTREAM The pipeline that carries the liquid is bolted or screwed the suction flange

1)SUCTION INLET:

5/7/2011 34 1)SUCTION INLET

SUCTION NOZZLE:

5/7/2011 35 SUCTION NOZZLE

2. IMPELLER & SHAFT:

5/7/2011 36 2. IMPELLER & SHAFT Impeller is the main part of a centrifugal pump. It move the liquid through the pump It is vary considerably in design It can be classified according to specific speed

IMPELLER TYPES:

5/7/2011 37 IMPELLER TYPES There are three types, depend upon the pump size or type of liquid and required discharge pressure. Open Partially open Enclosed

IMPELLER:

5/7/2011 38 IMPELLER

IMPELLER CAVITATION:

5/7/2011 39 IMPELLER CAVITATION Cavitation : The formation and collapsing of bubbles inside the pump casing

COLLAPSE OF VAPOR:

5/7/2011 40 COLLAPSE OF VAPOR

PARTS OF IMPELLER:

5/7/2011 41 PARTS OF IMPELLER

3. PUMP CASING:

5/7/2011 42 3. PUMP CASING Centrifugal pump casing (Housing) encloses the rotating parts The suction and discharge nozzles are usually in the lower casing The upper have can be easily lifted for inspection There are many types of casing, ex. Volute and split.

4. DISCHARGE OUTLET :

5/7/2011 43 4. DISCHARGE OUTLET The liquid leave the pump under pressure through the discharge outlet The discharge outlet is the downstream side of the pump The discharge flange is located at the large end of the volute.

5. SEALS:

5/7/2011 44 5. SEALS All pumps developed pressure to pump the liquid. The pressurize liquid must be contained by a seal to prevent leakage around the drive shaft . There are many types of seals that are used in many types of pump. Ex Wearing ring Packing Mechanical seal

Wearing Rings:

5/7/2011 45 Wearing Rings Centrifugal pumps contain rotating impellers within stationary pump casings.   To allow the impeller to rotate freely within the pump casing, a small clearance is designed to be maintained between the impeller and the pump casing.   To maximize the efficiency of a centrifugal pump, it is necessary to minimize the amount of liquid leaking through this clearance from the high pressure or discharge side of the pump back to the low pressure or suction side.

Slide 46:

5/7/2011 46 Some wear or erosion will occur at the point where the impeller and the pump casing nearly  come  into  contact    This  wear  is  due  to  the  erosion  caused  by  liquid  leaking through this  tight clearance and other  causes.   As  wear occurs, the  clearances  become larger   and   the   rate   of   leakage   increases. Eventually,   the   leakage   could   become unacceptably large and maintenance would be required on the pump. To minimize the cost of pump maintenance, many centrifugal pumps are designed with wearing rings.

STUFFING BOXES:

5/7/2011 47 STUFFING BOXES In almost all centrifugal pumps, the rotating shaft that drives the impeller penetrates the pressure boundary of the pump casing.  It is important that the pump is designed properly to  control  the  amount  of  liquid  that  leaks  along  the  shaft  at  the  point  that  the  shaft penetrates  the  pump  casing.    There  are  many  different  methods  of  sealing  the  shaft penetration of the pump casing.  Factors considered when choosing a method include the pressure  and  temperature  of  the  fluid  being  pumped,  the  size  of  the  pump,  and  the chemical and physical characteristics of the fluid being pumped. One  of  the  simplest  types  of  shaft  seal  is  the stuffing  box

Slide 48:

5/7/2011 48 The stuffing  box is  a cylindrical space in the pump casing surrounding the shaft.   Rings  of packing material are placed in this space. Packing is material in the form of rings or strands that is placed in  the  stuffing  box  to  form  a  seal  to  control  the  rate  of  leakage  along  the shaft.    The packing rings are held in place by a gland.   The gland is, in turn, held in place by studs with  adjusting  nuts.   As  the  adjusting  nuts  are  tightened,  they  move  the  gland  in  and compress  the  packing.   This  axial  compression  causes  the  packing to  expand  radially, forming a tight seal between the rotating shaft and the inside wall of the stuffing box.

Slide 49:

5/7/2011 49 The  high  speed  rotation  of  the  shaft  generates  a  significant  amount  of  heat  as  it  rubs against the packing rings.   If no lubrication and cooling are provided to the packing, the temperature of the packing increases to the point where damage occurs to the packing, the  pump  shaft,  and  possibly  nearby  pump  bearings.    Stuffing  boxes  are  normally designed  to  allow  a  small  amount  of  controlled  leakage  along  the  shaft  to  provide lubrication and cooling to the packing.   The leakage rate can be adjusted by tightening and loosening the packing gland

CENERIFUGAL PUMP OPERATION:

5/7/2011 50 CENERIFUGAL PUMP OPERATION

LANTERN RING:

5/7/2011 51 LANTERN RING The leakage rate can be adjusted by tightening and loosening the packing gland. Lantern  Ring It is not always possible to use a standard stuffing box to seal the shaft of a centrifugal pump.  The pump suction may be under a vacuum so that outward leakage is impossible or the fluid may be too hot to provide adequate cooling of the packing.  These conditions require a modification to the standard stuffing box. One  method  of  adequately  cooling  the  packing  under  these  conditions  is  to  include  a lantern ring.

LANTERN RING:

5/7/2011 52 LANTERN RING A lantern  ring is  a perforated hollow ring located near the  center of the packing box that  receives  relatively cool, clean liquid  from either the discharge  of the pump or from an external source and distributes the liquid uniformly around the shaft to provide lubrication and cooling.  The fluid entering the lantern ring can cool the shaft and packing, lubricate  the packing,  or seal the  joint between the  shaft and  packing against leakage of air into the pump in the event the pump suction pressure is less than that of the atmosphere

MECHANICAL SEAL:

5/7/2011 53 MECHANICAL SEAL Is used in high pressure pumps Is used in chemical pumps and liquids such as gasoline, acids and ammonia. There are two types: Rotating seal Stationary seal

ADVANTAGES OF DISADVFUGAL PUMPSANTAGE OF CENTER:

5/7/2011 54 ADVANTAGES OF DISADVFUGAL PUMPSANTAGE OF CENTER They are the least expensive of pump to build They have only one moving part. They do not need a lot of maintenance The main disadvantage is must be primed before they are started

II. DISPLACEMENT PUMPS:

5/7/2011 55 II. DISPLACEMENT PUMPS Introduction Displacement pump types Reciprocating & Rotary Pumps Major parts Describe the operation Advantages & Disadvantages Drawing symbol

INTRODUCTION:

5/7/2011 56 INTRODUCTION Rotary &Reciprocating pumps are positive displacement pumps. Positive displacement pump can be classified by the type of motion of internal elements The motion may be either rotary or reciprocating

Basic Types:

5/7/2011 57 Basic Types

a) Rotary pumps:

5/7/2011 58 a) Rotary pumps

Major Parts of Rotary Pumps:

5/7/2011 59 Major Parts of Rotary Pumps The major parts of rotary pumps are the: Suction Inlet Pumping Element/Drive shaft* Housing Discharge Outlet * The pumping elements in each of the four types are different.

Gear pumps:

5/7/2011 60 Gear pumps

1)External pumps:

5/7/2011 61 1)External pumps The pumping element in external pump consist of two gear wheels inside the housing. One gear is driven by the motor (Drive gear) The driven gear connected directly to the drive shaft

External Pumps Operation:

5/7/2011 62 External Pumps Operation

External Pumps Operation:

5/7/2011 63 External Pumps Operation From the figure : Liquid enters the pump through the suction inlet. As the gears rotate, liquid is trapped between the gear teeth and the housing. In suction side, volume expand In discharge, volume decrease When the gear teeth mesh, the liquid is squeezed out through the discharge outlet

2) Internal Gear Pumps:

5/7/2011 64 2) Internal Gear Pumps This design consist of internal spur gear and external housing. As a power is applied to either gear, the motion of the gears draws fluid from tank and forced it around both sides of the crescent seal (seal between S & D)

3) Lobe Pumps:

5/7/2011 65 3) Lobe Pumps The pumping element in this pump consists of two close-fitting parts, which are called rotors. The lobe trap the liquid and carry it around to the discharge outlet.

4)Screw pumps:

5/7/2011 66 4)Screw pumps Gear pumps use toothed gears turning inside a close tolerance housing to draw-in liquid and then squeezing it out ahead of them. Paddle steamers used the same principle of operation. These pumps are positive displacement pumps and anything drawn into them will be forced out. As a consequence they can generate very high discharge pressures. Materials of construction vary from metals of various types and hardness through to plastics of various types and hardness.

Advantages & Disadvantages of Rotary pumps:

5/7/2011 67 Advantages & Disadvantages of Rotary pumps High pressure capability (up to 10,000 psi) Small, compact size. High volumetric efficiency. Small change in efficiency through the design pressure range Great flexibility of performance. Only the disadvantage is the gear must fit close together.

Reciprocating Pumps:

5/7/2011 68 Reciprocating Pumps Introduction Major Parts Pump Operation Main types Drawing Symbol Advantages & Disadvantages

Introduction:

5/7/2011 69 Introduction Reciprocating pumps, like rotary pumps, are positive displacement pumps. Reciprocating means to move with a back and forth motion. The main parts are piston and cylinder The main types : Axial design Radial design

Major Components:

5/7/2011 70 Major Components Main Parts Suction Inlet Valve Cylinder Piston Discharge Outlet Valve Housing

Disadvantages:

5/7/2011 71 Disadvantages There are two main disadvantages of this type of pumps : Expensive to repair Deliver liquid with pulses pressure

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