SELECTION OF PUMPS

FERNANDO CHANDUVI

KINGSTON JAMAICA

MARCH 2011

TCP/JAM/3203 PROMOTING RAINWATER HARVESTING AND SMALL SCALE IRRIGATION IN SOUTH SAINT

ELIZABETH

FAO AND NATIONAL IRRIGATION COMMISSION LIMITED

IMPORTANT SUBJECT MATTERS

TYPES OF PUMPS

PRESSURE VS FLOW

SELECTING A PUMP

PUMP CURVES

SERIES AND PARALLEL

SELECTION OF PUMPS

TIPS:

1. DESIGN YOUR IRRIGATION SYSTEM FIRST, THEN SELECT THE PUMP

2. UNDERSTAND LABELS: 20 GPM AT 45 PSI OR 40 GPM AT 20 PSI

TYPES OF PUMPS

1. BY POWER: (I) ELECTRICAL AND (II) ENGINE POWERED: GASOLINE, DIESEL, PROPANE.

2. BY PRESSURE: (I) DISPLACEMENT PUMPS AND (II) CENTRIFUGAL PUMPS

TYPES OF PUMPS

ELECTRICALLY DRIVEN ENGINE DRIVEN

GAS ENGINE IRRIGATION PUMPS

GAS ENGINE IRRIGATION PUMPS

CHARACTERISTICS FOR HONDA GAS IRRIGATION PUMPS

DIESEL IRRIGATION PUMPS

DIESEL IRRIGATION PUMPS

DISPLACEMENT PUMPS

PISTON PUMPS, DIAPHRAGM PUMPS, ROLLER-TUBES, GRASSHOPPER-OIL WELL PUMPS.

USE TO MOVE THICK LIQUIDS.

THEY CREATE A VERY HIGH PRESSURE VERYPRECISE FLOWS.

USE FOR FERTILIZER INJECTORS, SPRAYS

DISPLACEMENT PUMPSA Positive Displacement Pump operating against a closeddischarge valve, will continue to produce flow until thepressure in the discharge line are increased until the linebursts or the pump is severely damaged - or both.

A relief or safety valve on the discharge side of thePositive Displacement Pump is therefore absolutenecessary. The pump manufacturer has the option tosupply internal relief or safety valves. The internal valveshould in general only be used as a safety precaution, anexternal relief valve installed in the discharge line with areturn line back to the suction line or supply tank isrecommended.

DISPLACEMENT LOBE PUMPS

CENTRIFUGAL PUMPS

Almost all irrigation pumps fall into this category. A centrifugalpump uses an "impeller" (sort of like a propeller) to spin thewater rapidly in a "casing or "housing.This spinning action moves the water through the pump bymeans of centrifugal force. Centrifugal pumps may be "multi-stage", which means they have more than one impeller andcasing, and the water is passed from one impeller to another withan increase in pressure occurring each time. Each impeller/casingcombination is referred to as a "stage". All centrifugal pumpsmust have a "wet inlet", that is, there must be water in both theintake (inlet) pipe and the casing when the pump is started. Theycan't suck water up into the intake pipe. They must be "primed"by adding water to the intake pipe and case before the first use.

CUT-AWAY OF CENTRIFUGAL PUMP

PARTS OF CENTRIFUGAL PUMPS

FLOW IN CENTRIFUGAL PUMPS

SELECTION OF PUMPS

SUBMERSIBLE PUMPS

Submersible pumps are installed completelyunderwater, including the motor. The pump consistsof an electric motor and pump combined in a singleunit. Typically the pump will be shaped like a longcylinder so that it can fit down inside of a well casing.Although most submersible pumps are designed tobe installed in a well, many can also be laid on theirside on the bottom of a lake or stream

SUBMERSIBLE PUMPS

SELECTION OF PUMPS

TWO PARAMETERS ARE NEEDED TO PROPERLY SELECT A PUMP:

1. TOTAL FLOW REQUIREMENT

2. TOTAL DYNAMIC HEAD

SELECTION OF PUMPS

TOTAL FLOW REQUIREMENT, EXAMPLES:

1. BUILDING WITH ELEVATED TANK (10 M3CAPACITY). CALCULATE THE FLOWREQUIREMENT. ANSWER:

SELECTION OF PUMPS

TOTAL FLOW REQUIREMENT, EXAMPLES:

2. JAMAICA. IRRIGATION OF 400 M2, IRRIGATIONWATER REQUIREMENT 5mm/day, 5 houroperation (solar powered pump). Answer: inliters/minute or gpm.

SELECTION OF PUMPS

TOTAL FLOW REQUIREMENT, EXAMPLES:

3. JAMAICA. WESTMORELAND IRRIGATION OF13,200 M2, CROP WATER REQUIREMENT5mm/day, irrigation every 72 hours, dripirrigating 70% of the area. Answer: inliters/minute or gpm.

TOTAL DYNAMIC HEAD

TOTAL DYNAMIC HEAD

Discharge Head: is the vertical distance between the pump datum point

and the liquid surface in the receiving tank. The pump datum is at the

center line for horizontal pumps and at the entrance eye of the impeller for

vertical pumps.

Suction Head: if the water to be pumped has its surface ABOVE the center

of the pump, then this relationship is called a "suction head". More

technically, it is the positive vertical distance between the pump datum and

the liquid surface in the suction well.

Static Head: "Static head is the distance that the water is to be lifted."

Therefore, if the liquid level is above the datum, then it is a "positive value",

as the water does not need to be pumped to that elevation. In the

calculation:

(Static Head, ft) = (Discharge Head, ft) - (Suction Head, ft)

SELECTION OF PUMPS

TOTAL SUCTION LIFT

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SOLAR POWERED PUMPS

SUMERSIBLE SOLAR PUMPS

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VERTICAL TURBINE PUMP

SUBMERSIBLE PUMPS

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TOTAL DYNAMIC HEAD: http://www.mcnallyinstitute.com/07-html/7-01.html

http://www.rainforrent.com/Training/PumpTraining.pdf

Irrigation pumps selection

http://www.ag.ndsu.edu/pubs/ageng/irrigate/ae1057w.htm#Propeller

http://www.ag.ndsu.edu/pubs/ageng/irrigate/ae1057w.htm#Pump%20Selection

SELECTION OF PUMPS

PLEASE REVIEW CATALOG:

http://issuu.com/webdox/docs/pedrollo_2010_catalogue

PUMP SCHOOL:

http://www.pumpschool.com/index.htm

http://issuu.com/webdox/docs/pedrollo_2010_cataloguehttp://issuu.com/webdox/docs/pedrollo_2010_cataloguehttp://issuu.com/webdox/docs/pedrollo_2010_cataloguehttp://issuu.com/webdox/docs/pedrollo_2010_catalogue

THANK YOU VERY MUCH