Hemanth Karmali & Deepak Pai- Fomento

8/14/2019 Hemanth Karmali & Deepak Pai- Fomento

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PIT WATER MANAGEMENTPIT WATER MANAGEMENT

MENSURATION

PUMP SELECTIONSTATUTORY REQUIREMENT



• RAINFALL V/S PIT VALUE DATA• LEVELWISE AREA AND VOLUME

• CATCHMENT AREA

• WATER LEVEL TO ACHIEVE

• TIME FRAME

• SEEPAGE

• PUMP SELECTION

MENSURATIONMENSURATION



Rainfall measurement, Catchment area give the idea about the Quantity.

Rise in pit water level at particular contour can be used to ascertain quantity.

Difference in quantity from catchment area and in pit at that level givesSeepage.

In fair season to ascertain seepage, stop the pump for 24 hrs(at least 8hrs),rise in water level can be used to calculate the quantity.

Pit bottom shall be surveyed up to date(summer) to calculate the quantity in

the pit.

Mine plan for the season shall determine the level up to which dewatering is tobe done. This will give the quantity. Quantity is devided by no of hrs (say within

2 to 4months as the case may be) to give per hour discharge required.

MENSURATIONMENSURATION contdcontd……



1) Application Oriented: Domestic pump, industrial pumps, agriculture

pumps, lift pumps, submersible pumps, metering pumps,vaccum pumps,

dozing pumps, fire fighting pumps

2) Flow and discharge capability: Axial, mixed, radial

3) Material handling Capacity: Acid,slurry,concrete,oil,waste

4) Construction Oriented: Jet Pumps, gear pumps, screw pumps, piston

plunger pumps, rotary pumps

5) Types of drives:Engine,electric,pneumatic,hand pump

TYPES OF PUMPSTYPES OF PUMPS



A centrifugal pump is one of the simplest pieces of

equipment. Its purpose is to convert energy of anelectric motor or engine into velocity or kinetic

energy and then into pressure of a fluid that is being

pumped. The energy changes occur into two mainparts of the pump, the impeller and the volute. The

impeller is the rotating part that converts driver

energy into the kinetic energy. The volute is the

stationary part that converts the kinetic energy into

pressure.

CENTRIFUGAL PUMPCENTRIFUGAL PUMP



Liquid enters the pump suction and then the eye of the

impeller. When the impeller rotates, it spins the liquid

sitting in the cavities between the vanes outward andimparts centrifugal acceleration. As the liquid leaves the

eye of the impeller a low pressure area is created at the

eye allowing more liquid to enter the pump inlet.

CENTRIFUGAL FORCECENTRIFUGAL FORCE



CENTRIFUGAL PUMPS

RADIAL FLOW MIXED FLOW AXIAL FLOW

Radial Flow - a centrifugal pump in which the pressure is developed wholly bycentrifugal force. Pressure developed by centrifugal force onlyMixed Flow - a centrifugal pump in which the pressure is developed partly bycentrifugal force and partly by the lift of the vanes of the impeller on the liquid.Pressure developed by centrifugal force and kinetic energyAxial Flow - a centrifugal pump in which the pressure is developed by thepropelling or lifting action of the vanes of the impeller on the liquid. Pressuredeveloped by kinetic energy

CENTRIFUGAL PUMPS ARE CLASSIFIEDCENTRIFUGAL PUMPS ARE CLASSIFIED

INTO THREE GENERAL CATEGORIESINTO THREE GENERAL CATEGORIES



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 dischargefrom the pump converting velocity to pressure. This is accomplished by offsettingthe impeller in the volute and by maintaining a close clearance between theimpeller and the volute at the cut-water. P lease note the impeller rotation. A

centrifugal pump impeller slings the liquid out of the volute. It does not cup theliquid.

CENTRIFUGAL PUMP COMPONENTSCENTRIFUGAL PUMP COMPONENTS



A Centrifugal Pump is a variable displacement pump.The actual flow rate achieved is directly dependent on

the Total Dynamic Head it must work against.

The flow capacity of a centrifugal pump also dependson three (3) other factors:

Pump DesignImpeller Diameter

Pump Speed

CAPACITYCAPACITY



The specific speed determines the general shape of a centrifugal pumpimpeller. As the specific speed increases, the ratio of the impeller outletdiameter to the inlet of the eye diameter decreases. This ration becomes1.0 for an axial flow pump. Radial flow impellers develop head through

centrifugal force. Radial impellers are low flow high head designs. Pumpof higher specific speeds develop head partly by centrifugal force andpartly by axial force. A higher specific speed indicates a pump design

with head generation ore by axial forces and less by centrifugalforces. An axial flow or propeller pump with a specific speed of 10,000 or

greater generates its head exclusively through axial forces. Axial flowimpellers are high flow low head designs.

Specific speed (Ns) identifies the approximate acceptable ration of theimpeller eye diameter (D1) to the impeller maximum diameter (D2) indesigning an impeller:

Ns 500 to 5000 D1/D2 > 1.5 - radial flow pump

Ns 5000 to 10000 D1/D2 < 1.5 - mixed flow pumpNs 10000 to 15000 D1/D2 = 1 - axial flow pump

SPECIFIC SPEEDSPECIFIC SPEED



life cycle cost

1

2

3

ener cost

main costin. cost



Throttling: Most common sloution.Flow is controlled by increasinglosses in system.Which means losses of energy.

On and off control: Used incases where stepless control is not

necessary for instance when keeping pressure in tank betweenpre set limits. The pump is either running or stopped.

Variable speed Control: Reduce the speed of the pump and withthat flow generated which results in staggering energy savings

LIFE CYCLE ENERGY COST SAVINGLIFE CYCLE ENERGY COST SAVING



A Pump Performance Curve is produced by a pumpmanufacturer from actual tests performed and shows

the relationship between Flow and Total Dynamic Head,

the Efficiency, the NPSH Required, and the BHP Required.

Higher Head = Lower FlowLower Head = Higher Flow

Lower Flow = Lower HorsepowerHigher Flow = Higher Horsepower

PUMP PERFORMANCE CURVEPUMP PERFORMANCE CURVE



The capacity and pressure needs of any system can be defined with

the help of a graph called a system curve . Similarly the capacity vs.Pressure variation graph for a particular pump defines its characteristic

pump performance curve . The pump suppliers try to match the system

curve supplied by the user with a pump curve that satisfies these needs

as closely as possible. A pumping system operates where the pump

Curve and the system resistance curve intersect. The intersection of the

two curves defines the operating point of both pump and process.

However, it is impossible for one operating point to meet alldesired operating conditions. For example, when the discharge

valve is throttled, the system resistance curve shift left and so

does the operating point.

UNDERSTANDING CENTRIFUGALUNDERSTANDING CENTRIFUGAL

PUMP PERFORMANCE CURVEPUMP PERFORMANCE CURVE



The system resistance or system head curve is the change in flow withrespect to head of the system.It must be developed by the user based upon the conditions of service.These include physical layout, process conditions, and fluid characteristics.

It represents the relationship between flow and hydraulic losses in a systemin a graphic form and, since friction losses vary as a square of the flow rate,the system curve is parabolic in shape. Hydraulic losses in pipingsystems are composed of pipe friction losses, valves, elbows and other

fittings, entrance and exit losses, and losses from changes in pipe size byenlargement or reduction in diameter.

DEVELOPING A SYSTEM CURVEDEVELOPING A SYSTEM CURVE



A pump's performance is shown in its characteristics performance

Curve where its capacity i.e. flow rate is plotted against its developedhead. The pump performance curve also shows its efficiency (BEP),required input power (in BHP), NPSHr, speed (in RPM), and other

information such as pump size and type, impeller size, etc. Thiscurveis plotted for a constant speed (rpm) and a given impeller diameter(or series of diameters).

It is generated by tests performed by the pump manufacturer.Pump curves are based on a specific gravity of 1.0. Other specificGravities must be considered by the user.

DEVELOPING A PUMP PERFORMANCE CURVEDEVELOPING A PUMP PERFORMANCE CURVE



A typical performance curve (Figure D.01) is a plot ofTotal Head vs. Flow rate for a specific impeller diameter.

The plot starts at zero flow. The head at this point correspondsto the shut-off head point of the pump. The curve then decreasesto a point where the flow is maximum and the head minimum.This point is sometimes called the run-out point. The pump

curve is relatively flat and the head decreases gradually asthe flow increases. This pattern is common for radialflow pumps. Beyond the run-out point, the pump cannot

operate. The pump's range of operation is from the shut-offhead point to the run-out point. Trying to run a pump offthe right end of the curve will result in pump cavitationand eventually destroy the pump.

NORMAL OPERATING RANGENORMAL OPERATING RANGE



The affinity laws lay down the relationship between hydraulic characteristics and rotational speed ofcentrifugal pumps.Specific cases can use the general rule as follows:

1st Model Law

2nd Model Law

3rd Model Law

Q = flowH = headP = power input

N = speed

Affinity Laws

H1

H2

N1

N2



Impeller Trimming

Impeller trimming means the reduction of the impeller diameter to adjust the pump performance to theduty point.

Q = flow rate

H = headD = impeller sizeThe indices relate to the respective impeller diamete



NET POSITIVE SUCTION HEADNET POSITIVE SUCTION HEAD



A liquid cannot be towed in a suction pipe like a wheeled VIP

suitcase. To make it flow it must be pushed from behind by someexternal energy, force or head. Atmospheric pressure provides thishead on the free surface of liquid from which the pump draws theliquid.

FACTORS DEPENDS

1)Atmospheric pressure.

2) Absolute vapor pressure of liquid at pumping temperature.

3)Friction losses in suction pipe.

4) Suction Lift.

NET POSITIVE SUCTION HEADNET POSITIVE SUCTION HEAD



NPSH(NET POSITIVE SUCTION HEAD)

NPSH= Ha- hvp+ hst

Ha= atmospheric pressure in mwc

hvp= vapour pressure

hst= Total suction lift/ suction headNPSH(A) : NPSH AVAILABLE IS A FUNCTION OF THE SYSTEM.

NPSH(R) : NPSH REQUIRED IS THE FUNCTION OF PUMP DESIGN

FOR SATISFACTORY PUMP OPERATION

NPSH(A) > NPSH(R)

8 WAYS TO MURDER8 WAYS TO MURDER



OVERWORK IT: Run pump at higher capacities, head, speed.

STARVE IT: Do not feed pump with oil/grease.

STAB IT: Open the suction cover, fill it with sand, grit.

POISON IT: Change the fluid you are pumping.

CHOKE IT: Make NPSH available less than required by the pump.

FRY IT: Operate the pump at shut off for a long time.

SHAKE IT TO PIECES: Run the pump in misaligned condition.

NEGLECT MEDICICAL CHECK UPS: Avoid periodical check ups.

8 WAYS TO MURDER8 WAYS TO MURDER

MAINTAINANCEMAINTAINANCE



DAILY CHECKS

1. PRESSURE GAUGE READINGS

2. BEARING TEMPERATURE

3. OIL LEVEL/GREASE IN BEARING HOUSING

4. NOISE & VIBRATIONS

5. VOLTAGE & CURRENT

6. PUMP SHOULD NEVER RUN DRY

PERIODICAL CHECKS

1. CHECK THE ALIGNMENT OF PUMPSET

2. CHECK THESEALING CONNECTIONS

MAINTAINANCEMAINTAINANCE

CHECK S DURING RUNNING/OPERATIONCHECK S DURING RUNNING/OPERATION



1. PUMP IS RUNNING SMOOTH. CHECK

2. NO MECHANICAL FRICTION IN PUMP

3. POWER CONSUMPTION WITHIN LIMIT

4. HEAD AND CAPACITY DEVELOPED BY THE PUMP IS AS SPECIFIED ON THENAME PLATE

5. BEARINGS ARE NOT GETTING HOT

6. GLAND LEAKAGE IS NORMAL

7. PUMP SHOULD SWITCHED OFF ONLY AFTER CLOSING THE DELIVERYSIDE VALVE

CHECK S DURING RUNNING/OPERATIONCHECK S DURING RUNNING/OPERATION

PRE COMMISSIONG CHECK SPRE COMMISSIONG CHECK S



PUMP ROTATES FREELY

DIRECTION OF ROTATION OF MOTOR/PUMP IS CORRECT

OIL LEVEL IN BEARING

ENSURE PRIMMING

VALVE ON DELIVERY SIDE IS CLOSED

PUMP SET LEVELLED PROPERLY

ALLOW ENOUGH SPACE AROUND PUMP

FOUNDATION SHOULD BE SUFFICIENTLY RIGID TO ABSORB SHOCKS

PROPER PIPE SIZES

PROPER SUPPORTS

PROVIDE NRV AND GATE VALVE IN DELIVERY LINE

PRE COMMISSIONG CHECK SPRE COMMISSIONG CHECK S

SAFETY REQUIREMENTSSAFETY REQUIREMENTS



• LAND BASED and PONTOON PUMPS

• CLEAN AND TIDY ARRANGEMENTS

• FENCING

• LIFE GUARDS & JACKETS

• LIGHTING

• FIRE EXTINGUISHER

• CERTIFICATION CONSTRUCTION OF PONTOON

• LIFE GUARD & JACKET

• CODE OF PRACTICE

• ELECTRICAL SAFETY

• VOCATIONAL TRAINING FOR OPERATORS

• FIRST AID BOX

SAFETY REQUIREMENTSSAFETY REQUIREMENTS



Code of practice: is the document which gives thecomprehensive topic wiseaspects to be followed during operation, maintenance of the

pontoon andpumps.

Construction and certification of Pontoon: pontoon shouldhave more than onetanks, Pressure testing is required, Draught levels should be

noted andwatched for any change, Man holes for inspection, stabilitytests, Certificatefrom Naval architect.

PUMPING AND COSTSPUMPING AND COSTS



• Pumping is inevitable for mining below water table

• In one of our cases it goes 10% of per ton digging cost

• Cost can be controlled by

• Selection of right pumps

• Operating the pumps in the curve range

• Minimizing friction loss in delivery pipeline

• Efficient prime movers

• Operating the pumps round the clock

PUMPING AND COSTSPUMPING AND COSTS



PIT TO PIT DEWATERING



PIT TO PIT DEWATERING

• USE OFSUBMERRISBLE

PUMPS

Hemanth Karmali & Deepak Pai- Fomento

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