Tài liệu treadle pumps for irrigation in africa doc

The operator stands onthe teas, resing the pistons up and down in a rhythmic motion ‘Two pumps have developed rom this ides, The first was suction pump cit water From a shallows source a

International Programme for

ws

) Technology and Research in

= Irrigation and Drainage

International Programme for Technology and Research in

Irrigation and Drainage

TREADLE PUMPS FOR IRRIGATION

IPTRID Secretariat

Food and Agriculture Organization of the United Nations

Rome, 2000

ii IIIIIIIII 85LR-Y

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Trade pans for irigation ia Africa ụ

Contents

Trae paps for ierigation Aiea

+ Felicity Chanceloe, HR Wall

social and gender issues

ton, for additional materalon Zambia and for her helpful discussions on + Colin Oram Development Technologies Unit, University of Warwick UK foris comments on altemative approaches io weadle pump design

+ Jon Kilgour, agricultural engineering consultant (uni ecently at Silsoe College in the United Kingdom), for is most help comments on reade pump mechanics and power outputs from human beings

‘+ Arumugam, Programme Manager, IPTRID, FAO, Rome, who assisted in the preparation ofthis report,

‘vith support from the IPTRID team,

Trade pps or iegation in Afric

Are treadle pumps a viable option for Africa?

Tao runes = nae An sey?

Over the past decade, a

revolution has been taking pÌ

ircigation in the developing world with the

introduction of the treadle pump This simple,

human-powered device can be manufactured and

‘maintained at low cost in rural workshops in

developing countries Its aceptance in Bangladesh,

‘where it was frst developed inthe early 1980s, has

been described as extraordinary, Over 500 000

‘pumps ae now in daily se in that county

How teadle pumps work is desribed in detail

inthe relevant chapter The principle is based on

suction ft using a cylinder and piston to draw water

from a source below ground level, for example a

river or shallow groundwater Originally developed

Forhand pumps for domestic water pumping it has

been skiflly adapted for use in irgation, where

much greater volumes of water are needed, by

changing the diving power from arms and hands

feet and legs These have much mote poverful

ruseles and so are capable of lifting much more

‘water Two pistons are used, each connected 10 &

‘weal The operator stands onthe teas, resing

the pistons up and down in a rhythmic motion

‘Two pumps have developed rom this ides, The

first was suction pump cit water From a shallows

source and discharge itovera spout into acanal for

_ravty irigation This was developedin Bangladesh

were farmers needed to if large quantities of water

through shallow lifts of 1-2 m The second

development was the pressure pump This works

‘on exactly the same principle asthe suction pump

butthe delivery end was modified sothat water could

be fed into pipe under pressure for sprinklers or

hoses Is also beter at iting water from deeper

sourees than the suction pump This development

‘came from the neds of African farmers who often

have o lit water from deeper sources in excess of

4m and ergate undulating land with sprinklers or

hosepipes

Whe ress ai avan.anbe ts APteN?

‘Both suction and pressure pumps ae available and

are in use in many countries throughout AVtica In

this report are details ofthe pumps used in Zambia,

Zimbabwe the Niger and Kenya,

"there isnot enough information availabe onal the design modifications to enable effective comparisons tobe made between pumpso the same type There are differences in design, ¢.g the

‘materials used, dimensions of components andthe

‘andards of workmanship and inthe methods of testing A more appropriate question, and one that

‘cane answered, is: Which is the best pomp for Paticuta site conditions? In Afiea, eadle pump development has been largely based on the Bangladesh pump with

‘modifications to suit Afsican conditions Ths is

‘essentially auction pump redesigned so that itean also be used as & pressure pump ApproTEC (Appropriate Technologies for Enterprise Creation)

1 non-goveramenta organization (NGO) based in Kenya, developed new designs for both uetion and pressure pumps, which i believess beer suited to

‘Alia lsdesign are based on the need to ift water fom deeper sources, irrigate more hilly lands and

be portable for security Essentially they exploit the principle of mechanical advantage (the lever principle) very effectively 1 get higher pressures

A recent design by a Swiss organization has Imroduced a suction pump that exploits the same principe

‘The frst choice is thus between suetion and pressure pumps The second choice is between the Bangladesh design and the Kenya design

Suction pumps

These ae designed fr lifting large volumes of water from relatively shallow water sources (1-2 m) Pressure is not usually an issue The Bangladesh suction pump mode s the most appropriate in this situation, because this isthe job it was designed to dda, When water sources are deeper, however the

‘ApproTEC and the Swiss suction pump designs,

‘with addtional leverage, tart come nto their own,

Average discharges based on sustainable

pumping over the day for one operatos would be in

the range of 1-2 litetsecond for shallow sources

‘This vould increase if there were W40 operators

working together, For the deeper sousces, lower

sustainable diseharges can be expected: | iret

Secon or less woul be more reais

wre pumps

“These are signed ta create pressure, othe volume

of ate ies less important Tey ae used when

‘water sources are deep (more than 4 m) and there

‘need to deliver water under pressure to sprinklers,

Adappers or toa header tank Tis requirement may

also be the result of ivjgating undulating or steply

sloping land The ApproTEC pressure pump model,

‘which exploits high mechanical advantage, is more

propriate in this situation, Total pumping

pressures up to M4 m can be obtained but the

tischarge wil be low this evel of pressure about

(0341 lire/second The Bangladesh model will sill

doa good job bat itis less appropriate andi will be

Aiicut to operate atthe higher pressures This is

rot the jb it was designed todo,

‘When quoting pressures, itis the otal pumping

pressure head that mates, This isthe sun of the

ston head ar the delivery ead Tey cannot be

Separated IF # pump produces a total pumping

pressure of Ld then witha Seton it of 31, thề

elivery pressure will be IT 2, Ite suction it

increases co 5m, the delivery pressure wil TA to

9m,

Ít showl! be noted that tease pump desiga is

ot an exact signee, because of the difinlty of

standardizing dhe power input which depends both

fn the physical stength of the operator and the

ability to sustain this power over a period of dine

‘Beware of comparing pup performance data

from diferent manufacturers, Some are tested in

laboratories, some in the feld, There are also

tunanswered questions about the operators used in

testing, Were they heavy or light? Was there ope ot

‘were thereto? How fast dl they teadle apd for

hhow long? Unless there is a common basis for

‘esting, «detailed comparison between pumps on 4

performance bass will ced care interpretation Finally, deciding whieh pump is bes isnot just

4 question of technical performance Judgement

‘ust be based on a wide range of factors including

costs and benefits, reliability maintenance,

vailahlity of spares and a complex range of local

social issues The experince of others in dealing

Are eae paps a able option for Africa?

with these issues forms an important part of this report

‘Pump prices in Africa vary from county o country but are in the range USSS0-130 (see Table 1) The ferences are due t he different costs of labour

‘and mates in each country

“Table 4, Pump prices

‘entry Sutton pomp Pressure ne

ff martcup for pimps sld in Keay,

‘The mark-up by ApproTEC pays fortheservices they pat into the marketing efor, which is akey puunp sas,

In Zambia, prices vary at present, depenting on the way pumps are supplied Most retailers are tunable to get credit 0 boy pumps directly trom

‘manufacturers and so the majority of pumps are bought by an NGO, International Development Enterprises (IDE), ho pass them onto teilerson

‘scommission basis, IDE cates the financial burden land the retailer receives commission when pumps ate sold Ths out is move expensive than the more teNonal direct route fom manufacrerto etal, soIDE has intoduced a temporary subsidy to bring Prices int lin see How ae they soi to farmers),

yy stsay neve sess son?

“The data in Table 3 show that significant numbers have been sid on acommercal basis and give some idea of he kely uptake of tele pumps hused on the substantial levels of matksting thst have been used to promote them The majority ofthese pumps are reported tobe sil n se

The numbers give some indication oF the manufacturing capacity tha must be bil upto mest

‘he demand for pumps once promotional work begins

‘Nate that no all he pumps made in Kenya ae actually sold in Kenya They ave distributed theoughout Uganda and the United Republic of Tanzania as wel

One ofthe prerequisites for successful uptake socal

‘manufacturing capacity In most of the country

reviews pumps were snitilly imported into the

auntey {0 take advantage of well-established

esigns, Ths, however, quickly replaced with

Tocal manufacture All the pumps deseribed in this

report need sposialst SKIS and nls 10 produce

thom 404 good anda In most eases, NGOs have

taken onthe responsibility forappnoaching potential

manufacturers gwoviding them with desig

materials ists and specialist sols and hen raining,

thêm lơ cnsruet the puns

[In many counties, manuracturers proce only

the metalwork components known asthe pus ead

The NGO then takes onthe tsk of bringing to

the other components, before a pump is realy for

detivery to farmers These componcas include the

‘wooden treads rapes and the pump seals which

say be imported injection products, locally

praduced leather or ruber from tees, This Final

pump assembly process is potentially weak ink

inthe local supply chain al the nomen, although

strengthened hy the NGOs, To be sastainabe,

assembly wil nest 0 he earied oat locally bythe

‘anfactrer or the distributor

Most sorkshops ean manufaetore teedle pars

‘once staff are tained and have the right toa,

Manulaeteing precision ix importante pumps

ate to be durable and perform reliably and el

the tcl Consequendy smiporant aspects of local

production are quality and quality contol ever all

Aspects of the manafacturing pravess Because

Imamafacorers are fe) not Tai ith this, i

hecame necessary for the NGOs to introduce

stents oF quality eon an to in tain the

procedures, The process rejects all falty pups,

‘experienced early difficulties, Manufacturers really were no very customer orient it will

be so ine bere they realize thal gi quay rrnbct creates sisted customers and can bring

in more business This is the heginning of si sustainable supply chain

“The emphasis here ison selling pumps to farmers

‘96a commercial hass, rather than supplying them

2 gills The connection between the farmer as & feestomer and the manulacturer as supplier is generally nota good one A distribution network or upply chan is =senualto link the farmer ith the

‘anufactorer, It consists of manufacturers wholesales reales, NGOsfpariers and customers Gamers, In Zambia there are eight manufacturers 2Wretser snd 3Oaetise collaborating pares who

“real inwolved inthe dssibuton and sae of teadie pumps TIDE has een the expt or setting ap soppy ins in Zambia, This involves IDE ating a & distributor linking manutactuzers 4 retailers, hosaase many retailers dono have the capital or the aveess (0 credit to work directly with Imanofactrers, IDE established agreements with

‘manulactores to alles punnps wo be supplied on 3 cconsigament hssis for seat their offiees and through regisered setile, Reiikrsonly by IDE,

forpomps when they are sol for which they receive

‘econmission incentive The mone is then paid

the manutactorers to preuce more purps, In spite

fof few teothing problems, the aerangement

reported a he working wel

This input from IDE is only temporary resins are slowly being encouraged to go direct 9

ranulucturers and establish a more conventional

‘hin Some nleidy do thin are able to negotiate

ore competitive prices Once it has hecome mee

established, IDE intends 10 concentsate on

emotions aad mark

Retclers were selected because oftheir strategie

postin in major provincial towns, for their bevel

‘of eommitaeat to the programme, the sength and

reputation oftheir business and their accountability

and willingness 1 accept the Taw price mash-ups

that were being recommended, Agresments Were

‘made with theta to alere tothe pricing structure

Arreturn, cealers received pursps ona consignment

basis, together with promotional Lterdtofe and

‘operation an maintenance manuals, They were also

trained to use the pumps and in methods of

pronation

‘A group of sales ents was recruited to promote

tind sell pumps diretly to farmers and receive

payment on a commision basis

Tn Kenya, AppeoTEC takes responsibility for

‘onlerng and buy pumps from manufacturers an

forsale and delivery to etailrs or deers, Dealers

‘ust purchase a minimum of ten pumps but

APBtdTEC allows the first hatch of ten toe sold

‘on consignment This arrangement fs common for

re products in Kenya an eame aout from the

unjlingResv af many dealers take the Financial

Fisk of investment without proven local aks Later

btehes ar purchased with SO percent paid up trom,

although some dealers are paying in ull at delivery

INGOs who purchase pumps fom AppesTEC are

treated as dealers: they pay the wholesale price foe

tho paps

Sales through dealerships have proved to he by the bes! mode of distribution, Commissioned sales people fwd itil to make a iving solely

from pump sales, ApproTEC onginaly targeted

hardware stores in urhan or peri-urban cones as

pomp dealerships, However focus was ser shited

Toagriculaal and veterinary (ar-vet inp stones

‘small (o medivm-sized lows, because these

proved to have beter aeeess to customers There

ae at present over 80 dealerships in Kenya, The

United Republic of Tanzania and gan,

Ae wae pumps a abt ope for Africa?

Av the time of purchase buyers fill out siarglee am ghing degil oftheir location and Planned use, which allows them to be tracked for extension serves an manioring, Comprehensive regalarsurveysof randomly selected pup owners fare mde to determine the use and impact of the pumps

Inthe Niger there are cash los problems similar

tw those im Zambia, In such eases, manufacturers vide ered wo gardeners, especialy a ses where Thepumpsare no ell known A contract sarang with a gardener, who agrees to make a down payment (negotiable, but usually 50 pereenf) and gees 10 pay the halance y a mutually acceptable date the gardener defaults on payment, the

‘manufacturer can repossess the pump and keep the down paymtent ae hức (e, The village chief or another responsible member of the community

‘witnesses the conic

The supply chain must as function as a edit for spares maintenance services und feedback to manfactorrs Inthe Niger as part ofthe alters fare all the gardeners are visited at lest three

‘umes after one week, one month and si months —

by & field agent and a representative ot the ntaufacurer Dring the Fst visit aqui control check is made to ensure that manufacturers

‘continuing to follow the recommended norms for Imatrils and procedures The pup installation is

‘checked and site-specific suggestions may be made

to improve pump performance, The Fist visit i spacial important forthe fist fe punspsat anew site, Once several gardeners in an area ave some experience, they ae able to help thei aeihbours

‘ith installation problems Ha major manetactring Aetec is identified, the mantfuturer 6 contacted tnd obliged to correct the problem

‘The lick of an effective supply chain in Zimbabwe is undoubtedly linked othe poor uptake

‘pumps there They are well own in te unity but no single agency as taken it upon itself

‘murket them on wide scale and production i nat

If farmers want pumps let them come and huy them was « cammnn aide This isnot such & problem with well-known products bút more

Troe pops on eit in Mec

ressive marketing strategy is needed for new

Products farmers are going to bene

In Zambia, eadle pumps have been promoted

principally theovgh practical demonstrations on

farmer’ fied days atagsculual stows at markes,

jn farmers Fields ana IDE offices Dermonsiraion

tren have been established in ta

‘where rapid adoption cosld he expected These have

provide! Farmers with the opportunity iy out the

pump in thera time In these ease paps,

Jeaflts al brochures were distibuted to provide

information about the pumps and where they ean

be purchase

Other marketing activities have ineluded

advertising rt outlets and the pumps shxoueh

radio programmes, elevision and newspapers 1s

planned ost printing calendars and T-shirts that

show teadle pumps in se and proside details of

‘he beneis Village theatre performances too, have

trad very favour pat on sles,

May Partner organizations have also been

‘reerited to participate in promotion NGOs such

ais CARE Intemational, Africare, the US Peace

‘Corp many ethers have not ony promote the

use tee pam ut ive als porhased pans

For se in their own programmes,

Inthe Niger, publicity hasbeen an important pa

‘of masketing, The first slep in 4 malifaceted

bli’ campaign was to choose name fe the

pump Staft chase Nigya da Kokari, a phrase

meaning willingness and courage tats understood

‘vas commissioned lo wile ø song extolling the

ites ofthe pump and pubicz

Whas heen included in radio and television

swnnmenial and the brand name Niyya da Koka

is now el awn thao the coi:

exinion has heen a major factor in ereating

brand name eengnition, The same local taupe 8

commissioned to perform in a commercial for

television, preiuced in Hause and Dyerma, tha

clearly conveys the advantages of the pun in

comparison to witional roped eke iigtion

systems, Although this kind of publicity is

expensive the visual impact of seeing the pumps in

foton creates avery positive impression, The large

‘humier of people in rar areas who hase reported

Secing the television commercial has surprised

rot sta ‘Audiacasserte tape manals using the local

Tanguages of Hausa and Djerma are used in

ee 10 writen sinus and have find g

Ai TÌM PP UNNHHU ri PK?

Enterprise Works in the Niger investigated precondition for uptake parcel terial ses

fn the use of teeadle pumps They su

‘order for a technology to be commercialized nd doped, it shouldbe produced as cle tothe end- tse as posible I mast be lfordable forthe buyer and profitable forthe pralucer The technology must als funtion rsiably and the purchaser amust be satisfied [nly tikes ew dissatisfied eustomers

to vin the market for a new product, Bot ne technology can be eonsidered appropriate for ll conditions, This is where the identification af appropriate sites becomes imporiat, Appropriate criteria inst

st market lor vegetable products

44 Water source shin 6 m of the ground sarface fan adequate water supply 1 hireSecond per

— AAconcenieation of market gardeners rộng trai Tio watering methods

adequate lind avilable for ganlen expansion

‘The best way ta determine where there are concentrations of market gardeners iso stat at the markets By asking the vendors where the peaduce

‘was grow, the more important gardening ses ean

be identified Visits 0 markets also provide an

‘opportunity fr practical pump demonstrations

This depends om the erops, the climate and the effectiveness ofthe way the Farner uses ater, lạ trol terms assming an igation time of 20hours

er cok, erp water reguiement of 25 mim per week, typical of dry season in south Aiea, and @ power input of SO watts tony ane person

‘pumping water the ara tha can be rigated using

a twadle pump is approximately 0.28 ha Using watering ens under sar candiions would reduce

‘he ayeato0.03a, Surveys of snl scale igation

in Kenya indicate an average area of 1 ha for steton pany and 0.27 ha for pressure pumps 1

‘more than one operator is working the por the

Feigated area can be mich grees,

“Thereportd impacts farming prstices have been

substantial and includ:

Increased and aca under irigation:

* educod work tine compared with hucket in

+ adiional and new erops grown exch season:

+ inereased number of grossing cycles, as erops

ave ale grow faster with Full igaien, Witr si tp nu SH meses?

Theeconomic benoit of iniouing teal pumps

can be significa In Zambia, comes have sen

‘more than sifold trom USS125 achieved with

ocketidigalon ox035 haoflandlo USS8S0.] 700

‘sing weadle pumps This was atibuted to ineeased

‘top yields and t being ube oineoase the area of

land imigated Cropping intensity also rose some

cases upto 30D percent (three crops Year), with

roticeableinerecses i the vane of erops grown,

With mone water available, farmers were more

ili take risks with new erops Silas bent

have Been epee in other counties where Weal

pumps have been introduced

In adkition to the direct benelis for farming families there isthe positive effect on the whole

supply chain of manulacores, eaier and selling

agents, Employment is increased in rural areas

‘where artisans ae mansatuting pumps, carpenters

ae peodueing teadles and an increased worklorce

's noeded on the farm 0 cope with the adil

produce

‘ut « ord of waming The increase in erop rics cam bring with it the problem of market slat

‘shen supply exceeds demnd, This is particular

problem sith common household crops and itis

‘exacerbated by the tendency of Farmers to gr08 the

‘ame cops athe same time of yea The seach foe

new, pore distant markets may solve this difficulty

Fut it can efeate different problems Transports

‘costly and dificult find in remote ura ares with

Poorly developed feeder rads Lis als unreliable

Are weaile pumps a viable option fr Affoa?

A farmormay have to wait days or transport, whieh ray result i deterioration of perishable proce, win tr eces profits,

Strategies to avoid the glu problem include option of allerative cropping patterns uptake of contract farming

linking with bulk: buying compa

and food process

opting altrmative low-cost transport such as beyete-posred cars to gett distant markets Waterresourcesean also init economic growth

in small-scale igation & fos farmers pumping from a small seam or sallow grondwter may

ot cause much of «problem hut large nurses of farmers operating inthe same area could result

‘erexploiation ofthe resource to the dtsiment of everyone, Ifthe laa wtertahle dropped by one or

‘so meee, for example, this eould pa the water

‘beyond the rach oF teadle paps

‘migating crops, weeding erlizing and harvesting

of vegetables are gencrally considered In he Women's sctivites Women operate teale pumps

‘without any traditional or religious constraints and sce hiss an apportmity for empowerment Women fre largeted hy organizations promoting idle Dumps and used in publicity materi thas been feported that women find the pumps harder to

‘operat than men da They do, however find suction pumps easier to use than pressure pumps OF al the

‘pumps sold in 1999 in Zambia, oly our wer prchised by women, thanh wonte age the min ses of teadle puns

Tn Zimbabwe although teadle purops are nso widely used, che improvement of family nation aca rest of the inereace in garden produce has been noted in many areas There is lite esomontic benefit however, s most communities produce just enough for their own consumption, Very Tew farmers use read purnps to preduce vepetaes for marketing

“The cost of pumps is til heyond the reach of|

1 oinary communal farmers Mone than hal fof the pumps in use were donated, and are thus community property It has heen observed that

Treae paps for ieigtion in Afi

individually owned pumps are much better

‘maintained than those owned by the whole

community:

Pumps are mostly operated by women and

children, a they tend to do all work in the garden

Because an operators elevated above the ground

‘women do not feel comfortable standing on the

pumps for long periods They feel exposed and

consider it undignified A sensitive issue has been

‘men trying to discourage their wives from using the

pumps, because they become overired in the

evenings This issue is difficult to verify, although

some people helieve it is more speculation than

reality

Tn Kenya although men buy most ofthe pump

‘women mainly manage them and then contol and

benefit fom the additional income, However, most

‘of the pumps are actually operated by young men

hired by women managers In contrast o this, men

buy and operate most of the puraps used inthe Nir

‘Training forall vhose involved inthe supply’ chain

is essential if treadle pumps are to succeed,

Suggested taining needs for various groups are

Government extension staff who work directly

‘with ivigation farmers

‘+ Training to build up capacity in eigation in ex-

tension services, including horticultural methods

+ Igation techniques

+ Water management, including crop water re

(quirements and scheduling

+ ‘Treadle pam operation and maintenance

+ Stripping and assembling 2 pump to highlight

technical aspects and the importance of proper

insalation procedures and maintenance of each

Agronomic practices + Basic market economies of supply demand and the effects on prices

‘commercial hasis seem to be eal or the small farmer in this situation The evidence avaiable to date indicates that there is much to be gained by {aking up this type of technology

‘Altempts to use teadle pumps in Aftica inthe aly 1990s were les succesful than in Bangadesh Conditions in Aiea are very differen from those

in Bangladesh, however The groundwater s much deeper and the irgated land much more hilly so the water must be pushed much further from is source tothe pont of us, Development of pressure

‘pumps has helped to overcome this constraint and

"ha transformed the situation, resulting in significant

‘es of pumps in many countries inthe past fee years

Ics important to bear in mind the social and luca implications of intodcing pumps ofthis kin, if the economic benefits are tobe realized,

‘There will also bea great deal of work tobe done in setting up the supply chains and ensuring tha there

is sufficient manufacturing eapacity of a high

‘enough quality to meet the demand As demand usually needs to be stimulated when new tech- nologies ae inteoduce, ther isthe opportunity 0

‘combine marketing activities with the development

‘of supply chain fn this way it may be possible to halanee the level of expectation crested among farmers with the means of satisfying it

Al the purmps described in this report require specialist machine tools and parts to ensure pruction of efficient refible units Ther re those

‘who argue thatthe specials tools and components bring with hem an unaccepeable level of dependence

‘on others Ifspare parts ae not available ori local

skills are insufficient ta cope with routine

‘nainteanve ad repair the system sualibey tobe

‘stainable in the long term,

“Ta be profitable, echnology mus have a ly

‘overall cost — lo enough aot to onerexpose the

‘vue to debs, Ie mas then make money” Fear af

Faure as often driven people towanls high tech

solutions to avoid the problems of breakdown, Alt

machinery failseventaly In developing couse,

however, failure tends to veut sooner becuase

‘maintenance is uerer and the conditions are mone

hostile, The result ste machinery graveyards that

cam he seen surounding many towns and villages

For this reason, the nes for ston supply chains to

support the supply of spare pars and maintenance

nus ft he underestimated

‘A final comment rom experience in East Attica

indicates that four preconditions are vital forthe

sustained sueces of teal pumps:

‘+ 8: marker-driven demand and suitable envio

‘ental aml csonomic condiions and a signi

‘cant population ble wo lord the pomp and ss

‘ain loca demand fo hariculuee

Averell papa vibe pion fr fia

+ awellalesgned pump thts appropriate For the Foca arming conan and manuctring ss +L Tocal private sector capability foe mass pro

‘duction and quality conto + effective peivate-sectordsributon networks for agricultural inputs and equipment, including Transport nfastrastre ad

Donors and NGOs ca take ation vo Filia and cehance teadle pump use Donors ean fund vile projets where the four preconlions for sustained

‘success are met, NGOs can play an important re indemonsraion and promotion, Donors and NGOs, however, should not dane or sell pumps below retail cow, They should support he private sector tun! avoid ations which a skew the market and result i detrimen impacts on consumerdiven demand

esate pups for irgation i Mca

pumps — what are

?ysntraduction ofthe trealepusip, which ean

nanuaetured and maintained at low cost in rral

workshops, represents significant revolution in

small-scale itvgation i the developing woe ts

sgeoprance in Bangladesh, where it was frst

developed inthe early 1980s, has heen deavihelas

atsordinuy,\10toker S00 8 pumps now indy

tse in hat county

“The costs of huying running and mintaining

engine-driven pumps for iigation are prohibitive

for mast small lamers inthe developing world The

‘majority rely on tational human-powered water

ing devices but these to have ter deasbacks,

They are essentially bucket-liting technologies

‘operated fan, sch as shadoots and soaps, eich

fare slow and cumbersome und reine high labour

inpatstoinigate very smal plots of land Water iting

ales are at hex 3-10 mh Trea pumps ave

been changing alts They we the less, which have

‘much ionger muscles than dhe arms, They work i

comfortable, ythmic walking motion ling up

{o 25:5 mlthe by sustion from rivers or shallow

aroundivater~ enough to isigate between 03.04

‘hain most topics sand arid courte,

‘The first weadle pnp was designed and

developed hy Gunnar Barnes, « Nonevian agi

cultural engineer working forthe Rangpur Dinsipor

Rehahitation Service i Bangladesh in 1981, The

cay designs wheeled tapak-tapak pumps the

farmers, because f the sound they made

‘Treaale pumps of various designs ate now

available in many African cousties Various NGOs

introduced aor of hese From Asia Manafactring

has tended toe sall-sale, by blacksmith o small

centerprises, with an emphasis on Tow eos Prices

‘ary’ from country to country ut most pops are

Skt to farmers al bebwsen USSSULUN The Food

an Agriculture Organization ofthe United

{080 has promoted then rough is vatioas Special

Programe for Fad Sect (SPFS) initiatives A

"The lmteratonal Programm for Technology and Research in Irigation and Drainage (PTRID)

‘commissioned this report on the satus prospects Fortteadle pumps in Africa, particularly concerning

rw smaloldersean take upsuch devices to suppor itrigation la view ofthe fat tha real pumps ae

ho beiag used in many African counties, this document sastae-o-the arp identi what needs 10 he done by agencies danors, NGOS and

‘manufacturers to make such pumps seceptable and eeesiBle for smallholders fs emda iigation Proesionals, donors, decision makers ankd NGOs Promoting small-scale iigation in Ai

Information has been provided trom many sources Particulae reference is mua othe nations experts ho werecomtmissoned by FPTRID tocolact Uupiodate information from a number of lecan

“The root begins with a eview ofthe different teeadle pumps curcently in use in Attica and the information sailble onthe ecnieal performance, witha view totrying answer the question - Which

is the best treadle punip? OF perhaps more appropriately ~ Which is the best for a given

‘station? This is fellowed by repeats prepared by national experts onthe esperienee of sing tredie Dumps in ferent cous across Aiea, These

"` " snd social impact ofthis techtelogy chabge, is avcepeabiity and susainality This experience Should bop those whe ae just hoginning to thiak about cade pumps, wondering they are sght for

‘em and, if, haw best to inne the ino tir

Trae pps for ierigaion tn Africw

How mey won

A treadle pump comprises a cylinder fted witha

pistonand some means of pushing the piston up and

down (Figure 1)_ pipe connects the pump 10 the

Water source and atthe end of this pipe is 8 aon

Feturn valve that allows water o enter the pipe and

Stopsit from lowing back int the source The piston

and the cylinder must havea very close fit so that

‘shen te piston said, treats vacuum in the

cylinder and wate is sacked ito the pump When

the piston is pushed dow, the water is pushed

tyough a smal valve inthe pison oll upthe space

boveit, When the pistons raised agai, it is his,

‘water unit pours et over the rim af the esinder

and ito an ieigation channel or tank At he same

time, more water is dawn ito the space below the

piston, The downward stoke ofthe piston one again

pushes ater tech the smal valve ito the spice

above the piston andthe process is repeated

How treadle pumps work

“Thisisa very simple principe that hasbeen used forcentries for lifting water from steams and wells

“The amount that can be ited in this way is usualy small, however because pumps that use this idea

re normally hand operated and the effort required

to lft water is considerable, This has generally strcied thei wse to domestic purposes and for

‘watering animals This dea has now been skilfully adapted for se

Sn ierigation, where much greater Volumes of water

ed The mostimportant innovation has hoen to-change the driving power from arms and hands 0 feet and legs These have much more povwerful muscles and so are capable of lifting mich mone water Two cylinders ate used instead of one They are positioned side by side and chain or ope, which passes over pulley ora rocker bar, connects the

‘wo pistons so that when one piston i being pushed down, the other one is coming up Each piston is

‘connected 10 a real, The operator stands on the

treads and presses themupand down inarbythmic

‘motion lik pressing the pedalsonu bicycle Some

have also deseribed i a siniar to walking, This

*ythmic meted of devin the pam hs ined wide

ekepiinoe emongfarmsr and seems to be preter

‘oan mechanism that equies only one foot or as

sd ands

‘This pump has become known asthe suction

pump ani isused oda water vp from a wel oF

siver and discharge it into a canal fr irgaton But

Since its advent another fora of weadle pump has

‘heen developed which is commonly known as the

‘rcisure pump, Tia operies exacily Gc sume

Principle a the sution pup but the delivery end

Ts been modified so that water can be Fed imo a

pipe rather than an open channel Instead of water

owing over the tp ofthe eyinders into 3 channel,

the upward movement of te pistons pushes wate

lyoughasecond vale intoa deliver pips This valve

‘lores nde dovnvard stroke to tp the fl rom

Feversing In this way it possible to maintain 3

Presure inthe delivery pipe that an be sed to drive

Sprinklers or drippers o deliver water toa header

tank Hence die name pressure pup

‘These nol he ideal names, becuse they imply

thatthe two pumps are differen whem in realty the

both work onthe same suction principle, However,

these the names hathave been generally ocepted

ml so inaecordarce with common we they reuse

toughon this mana

Many professionals without an engineering

bbuckground often do nothave a good understanding

fof basic hydraulics and parping This section is

‘designe to clarify some othe important sis sch

as pressure, head and disearge and what is meant

‘ay sc terms a ston fil and Ueivery head,

Pressure and head

Prossre is defined ss force aeting uniformly aver

sanare [is normally measured in klo-Newtons per

sayare metre KN) some European cousties,

ingrams force per square centimetre kgtfem) is

sll used, Another common units the har One Bar

isthecquivalent atmosphere pressure and sequal

to T ket Many non-engincering professionals,

find ilo-Newtons confusing and much prefrto work

inkilograms lorcet), a itcan be easily related a

theeummon understanding of Klages sa measne

How eadle pumps work

fof weight This isthe unit of measurement used

‘trough the manual Pressure soften rlered to as ead of water

‘Tounderstand ths imagine along vertical abe, in

‘which the pressure is oe measured, connected ot pipe Water wllise up te tube, because of te water -ressre inthe pipe The height to which i sil is isa measure ofthe pressure, This is called the ead ands anther way in which pressure isexpressed It has the advantage of allowing changes inland topography that ean affect pumping pressure 1 be taken easily into agcount when working out presse requirements, ims, however, be lined tothe Nid inthe pipe, a diferent Mund would seo iferen hoights because of thet diferent densities, So the songetterm iouseis head of water The teatonship hotween pressure ad head is simple one

Head of water am)

0.1 pressure (Nie) 1" pressure (kgfent)

10 pressure char)

Asamexample, a pressure of Sar or keen)

‘would result in wate sing toa eight of 30min he tube, (For more explanation of pressure and other axpeets af heals, see Ki, 1998,

‘Aumospheric pressure, which is importa for pumping water, is equal 10 mead of water The easons for its importance are discussed in the next

Sietion tf Foroporating convenience pumps ae usally located shove the water source and a shot lent of pipe is sed to dra water into the pump This sealed the suetion pipe The dtference in height hoween the

‘water surface andthe pump isle the sero if

“The idea of set if and its imitations fone that

Js not well understood, so a woed of explanation i Peshops appropiate ere

Pumps donot actually suck water as is often imagine A pump takes water Irom the source in

‘much the same Way as you would suck up water theough drinking sw Tn fet you donot atuly suck up the water; you suek out the air fom the Straw and create a vacuum, Atmospheric pres des the est pushing doinon the water surface and forcing water up the straw 10 ill the vaewum, Atmosphere pressure thus provides the devin free but pats a limit on ow high water ean be hited in

‘his way H dues not depend om the ability of the person sucking At sea level, atmospheric pressure

ae pons

is approximately 10 m head of wate, so in theory it

‘an push water up to 10m Butif you were relying

tăng draw TÔ long for your water nes yos wou

dhol thirst! A7 mstraw would improve your chances

of survival and ¥ mo would be even beter ln other

‘words the shore the seas, the easier becomes to

201 water:

“This principle applies to all pumps, including

otcezed pumps and weal ums lel iho

te possible tit water by stetion upto 1 m,n

patie a sensible Finis 7m, ees of retion

Fosses in the svtion pipe and te efont required

sate vacuum under these conditions Even at his

love, here will be fils inoeping out ai fons

leaky pipe jimi and seats to maintain the vaca,

“The lower the suoton il, the easier will be to

‘operate the pomp,

The gueston othow to hilt water from a borehole

leper than 7m ovten arses, Clery in his situation

water cant be ited by any purnp operating at

_roand level Theol way to deal with this problem

‘sto lower the pap into the ground, so that ts ess

{hin 7m above the water surace This ean Be done

cither by using sabmersible pumpin hich ese

‘the pum is below the water level so thec ly ga

suetion~ or excavating down ad placing the pump

‘na shelf within 7 m ofthe water sfuce

For pursps operating at hish altudes, where

atmospheric pressure i less than a sea level, the

practical lini wl he lower tha 7,

otal pumping head

Tonal punping hcadisamoer wer at need eae

se This thes of the suction if an the delivers

Feu and is ore important for the pressure pump

‘The delivery head isthe pressure rested on the

elivery side of the puri is measured from the

nuniptothe point of water-delivery, Soi the suction

Tits ism and she pomp then delivers a7 m hea lơ

sone prilers hse pipe the ppg ead wild

be 11 my This represents the total height Une

hich the water must be fed rom source lo delivery

Point 17H m were ne maximum that a pump could

‘deliver, any change inthe sueton it wold dfseL

the delivery head For example if dhe suction hit

increased 08m then he delivery head would reduce

to Sm resting the same tot pumping head oF

Hm Just quoting delivery heads without any

reference 1 suction lit daes no provide enough

information about what a pump cand in tems of

‘pws tagh filters an Valves, Flow through edie pumps is To so for simply these effects have boon ignore

Remember: Tis pumping maa is he suc ơn 14 plus

tho every hea,

Ts myst

Although there are diferent desigso tread pup tvalabl, there ate several components which he} all have incommon (F

Pump eytiiery

‘Tho wse of to pump cylinders provides neatly coninuous low of waler Alttotgh this sot sở Smportant for gravity irrigation it can be an advantage for pressurized iigation, where the build

up of pressure is important to ereate a spraying sation, Cylinders ae normaly Between 75 man and 1mm indiaete A common darter is T00 mm,

“Materials used include stel plate bent into

«plinder, PVC pipe concreteand bamboo, The choice fof matesaisstronly influenced by loeal availabilty sandcont Steels good choice there a suficent shill machinery avaiable to bend iitnotheright shape, Bamboo hasbeen used wheres plentiful

—_ level butt does have a short working ile It not still fir pressure pumps

Pistons mose upd down in te cylinders when the

‘operator presses down on the weadles Steel rods

‘one the pistons athe eas, Te pistons eat

be made of stel, wood or plastic with leather or rubher cups or rings to form the seal with the eylnders The seals mast alsostand uptorthe gous

ff continually moving up and down against the

<ylinder wall (see Table 5 for lesson seal),

“The manifold is a ste! bos in a pressure pump tha

‘connects the inlet and outlet pipes tothe pump

“ylides, comprises to pars the inlet side, hich allows water ini the esliners, andthe outlet side Uwhich allows water to ent rom the cylinders tos delivery pipe The suction pomp only hay an nel

Figure: The base components of treacle pump

‘manifold 38 ater pis over the tp ofthe eylinders

aa spout and discharges into a channel

[Non rewum valves allow water to flow one way and

Stop i fom flowing back to the source, Teadle

pumps have several non-etun valves One ean

be located atthe entrance of the scion pipet top

it from draining every time pumping stops

Interestingly very few pumps se this valve, which

‘means that the pump must be e-prmed every time

pumping begins A second valves located atthe top

‘ofthe ston pipe in theinlt maifolt stp reverse

flow during pumping Pressure pumps havea thd

non-ftum vale inthe oat manifol to stopovers

Treadles

The operator stands onthe reales and poshes thems

‘upand downto work the pump They can be about I

‘metre long hinged atone end and supported at the

‘ther by a rope or chain running over pulley They

reconnected tthe piston dss hat the mevement

‘of the weadles is transferred tothe pistons Teeadles

{ean be made from see, wood or bamboo Teeadles

nos tobe strong enough t take the forces applied

by the weight ofthe operator

‘usually made of wood soaked in oil o reserve it and tolubricate the movement Analtemative tothe pulley farocking bar which s pivoted inthe middle (see ApproEC pumps ~ Kenya),

Frame

“Thecomponentsofthe teade pnp are mounted on frame, which keeps all the parts together and provides support forthe operator Some pump frames are made trom wood and are very portable This ean

‘be important when security isa problem and pumps

‘cannot be lft inthe fel overnight However, some

‘designs use sturdy metal frames which can standup tothe rigours of continual use; one design isencased imconerete see Swiss "eonerets” pump which makes itdificult to moxe and hence difficult ose

Poor peste FRATURES

“Treade pumps provide one ofthe best ways of using human powerto it water Sizing of the components tnd careful design are essential to ensure that hiss done in the most efficient manner Pomp output equirements of discharge and pressure must be

resale psn or eiotion i Ar

malchal vi) the mechanical components, sch as

the diameter ofthe pistons thet stroke Tenth the

‘weight ofthe operatorand the cadence tbe equeney

With whit the teadles are pushed up and down,

‘This process of design is complicated by the wide

‘araons of posible puri nocd ferent sites

athe wide range an ability operators wo mus

be comfonable when using the pm an not bent

‘overinsome awkward postion The design must be

8 simple as possible in terms of is minufcare

fd maintenance This section looks at these sues

‘nd explains, for example, why’som rele pups

have smal damitereylindessile hers have large

Haman power —w vet?

nis generally accepted that u reasonably fit, well

fed human being hetween 20 an AD years ol ean

praxluce& steady power auiput of around 73 alts

for long periods acne, 1986), This my not be

the cane in many developing countries so 2 more

reastceapt may be atosnd 30 0 40 wats, This

powers transfered tothe pump when the operator

‘ads with oe oat on each trea an pushes them

Lup and dow ina reciprocal motion This is 3 very

atoral moveriet or the human body it ean be

‘isan oe several hour ihe paramersof sake

Jeneth and the cadence are matched wi the abi

ofthe operator

A steady ouput of 75watts is ne cower ot

walking up sir thong 20 csocnze Tre may,

noses sith Sid lak bt by ng

ontnuoesiy fr 4-6 hours wach dy

Assuming a 75 watt ouput, iL possible to

ealedlste wht can be Jone with this human pose

Tn theory, if ction pup has a set it of LO

rn, then 75 watts sould produce a discharge of 7.5

liwesAeconsd, Mt 2.5:m suetion, this Would fall 193

Tigesecond anda Smit would he 1.2 Hivevsecond,

A the sustion lift inreases, the discharge ta ean

be achieved decreases, Its ns possible to conven

all he 75 watts into useful water pumped: some will

{nevitaly be lost theough retion nthe pipes and in

the punipand valves Inedicingan eficieey factor

fof $0 percent forthe conversion of human power

Jno water power woul reduce the discharge at 25

‘vsti from 8limevecomlt6 L5 irevSeeond

Fraenkel (1986, p.137) summaizes this by

cleulting he dsr and head Foran inp power

(of 75 wants a 50 percent eficensy ss shown in

‘bly the input poser an the ost in rms oF ress and discharge wil be mach greats

“This puts upper limits on what can be reality achieved with human paser

Remember! Ther so such ting as Hee ne you want tei sven auanty of wae Fore a ven opin yoo mis prod he Pan power foo Tho

up ut provides @ moe eit maane ot Eenverting homan poaer lo wøtepowar Dự

Pump ergonomics Ergonomics the science of matching people with Imachines ~ inthis case matching operators with ma izes ann dimensions are chosen to get the bes out of the Thumsan power input an ensure dat the pumps ae

‘norte to operate:

Pistontstinder diameter Pion and eslinder diameters range between 75 50mm, ith [0-meeigg common choice Psion sianter puts an upper init on de pressure that can beachieved toe Discharge

Stroke length

‘Thete are wo stroke lengths to consider the foot stoke length and the piston stroke length The Foot

‘teoke length ste vertical distance betwen the eet

‘wllen one fot is raise and the others at lowest point, Ite stoke i 00 shor, the leg muscles tre

‘uickl:ifitistoo long the lez muscles are staining ofthe best known ways of using

‘human leg power, The distance between hieyele pedals approsinitaly 340 aim, which would bea Jong stukefors read pump andthe pumping speed Aeadences woul be slo, The stroke i governed by

‘what isa comfortable spec to operat the pump A stroke length of 100-350 mane ypicl range bat it depends om how the pump wil he use Given

‘Shes, an operator would normally choose a shor Stroke length for high heads and a longer stoke for loss heads

“The piston stoke length is the vertical distance

"Imough which the piston moves during pumping, On

6

some pumps thisis the same asthe Fo stroke length

but this is not always the ease (see Mechanical

aavaniage),

Piston stroke volume

‘This the volume of waterifted during each stoke

‘ofthe pump Itcanbe calculated by multiplying the

“area of the piston by the piston stroke Feng

Cadence

“This isthe requency with which the reales move

Uupand down, A cadence up 6Deyeles per minute

's a comfortable speed for most operators This

determines the pump discharge which can be

calculated by mulplying the piston stroke volume

by thecadence tis important to make sre the units

fae all the same to get an accurate result in ites!

Second Pump cadence is variable, ast depends on

{he individual operator Pump discharge wil vary as

result ofthis,

oot force

“The total pumping head is created by the Force on

the piston from the operator pushing down om the

‘readle For comfortable pumping this downward

Force should not exceed 80 percent ofthe operators

\weightand not more than 70 percent for shoe periods

For the pump to be suitable for men, women and

<hikdeen and for a range of pumping heads, it should

hedesigned fora foot force of 15-30 kgf (150-500)

“The piston Force must also overcome the friction in

the eylinders nd in the pipes

Mechanical advantage

On many pumps, its possible For operators to move

thie position along the wads, so that they can

change the force needed on the pistons while

‘maintaining a steady and comforable oat ace, This

‘movement also means thatthe pump ean accom

‘modate operators of different weehts each able to

find a suitable and comfortable pumping position,

‘This is an important aspect of pumping: it can he

‘much less tring when operators can change their

position rather than trying to produce a particular

force at fixed position on the reads

Tn mechanical terms, this positioning of an

‘operator relative tothe piston is based onthe lever

principle When an operator is standing on the

‘neadles immediately above the pistons the pushing force is directly transferred to the pistons An

‘operator's downward force of 30 kgf (300 N) thus

transfers directly a force of 30 kgf to the piston

(Figure 3-1) tae operator moves away from this,

Hew tea pany work

Figures: Using mechanical advantage piston force = Foot force

‘on the piston (Figure 3-2), The converses also tue

Tí the operator moves to reduce the distance tothe pivot paint Smy the downsardforson the piston sls redices 024 kf (Figure 3-3), This ato the distance ofthe operator and the piston Fem the pivot points know asthe mechanical advantage In the Fist ease it has aval of 12 and in the second 0

"Although mechanical advantage is deseribed above in tems othe position of an operator ithas a direct bearing on the movement ofthe operator in terms of foot stroke length and piston stoke length (Figure A mechanical advantage of | means that the foot stroke length is equal to the piston stroke length I the mechanical advantage is increased to

3 the piston stroke would be only one thd of the footstroke length Asthestroke length ofthe operator {slimitedto approximately 350 mim the piston stroke Jength would be one third of this 115 mm,

In proctial terms, this means that light operator such asa child, could operatea pump by standing as

“readle pumps for ivgation in Aico

Figure tect of mechanical advantage on foot

and piston stroke longth

faraway as posible from the pivot totake vantage

of the extra leverage A heavy oF strong operator

could move closer to the pivot for a comfortable

pumping postion also means that greater pumping

pressures can be achieved because of the greater

ores but this isthe expense of volume lifted per

stroke, because ofthe reduced piston stroke length,

‘Suggested mechanical advantage ranges between

(0.5 to 4, But there isa practical upper limit to this

vantage asthe pump might overtum ifthe operator

Sands atthe extzeme end of the reales

A suunmary of desirable features

AA summary of the range of desirable design features

‘The concept of discharge i familia to most people

who deal with water, Almost the fst question thats

asked ofa pump is~ Wha discharge cant produce?

Discharge can be measured in many differen units,

eg, liteIsecond, cubic metres per hour (7B) oF gallons per minute tis measure of the volume of Water flowing per unit of time For readle pumps, the same question is asked but the answer isnot so straightforward This is because most eadle pumps đảo not produce & continuous steady flow and the

‘put depends so much on the operator Tosa that aireadle pump can produce 2 ltessecond needs to

be qualified with how the operator achieves this It may be a heavy ora ight operator It may even be two operators working together on the same pump may be a continuous steady flow but is it sustainable overlong periods ors it high low only achievable in short bursts of high power input? Did the operator work a typical day of, say six hours and take tests for ten minutes every hour or swap

‘with another operator?

‘Theteisclearlya need o standardize the meihod

‘of measuring discharge iit sto have meaning for comparing pump performance and for choosing one that is suitable fora particular job This is not the

‘resea situation In this manual diferent ways of assessing discharge values are used by different investigators Some discharges are measured under laboratory conditions wih information given about

‘the operators abil Some are measured in the field

‘nd make allowances for rest periods giving an average discharge over the day Some quote the ischarge based on the amount of water pumped over longer period of time and work outhe sustainable discharge over that period This is motto say that fone method isthe right way There ae several ways fof doing it and so one must be careful to compare ike with ike

‘One way to compare pumps is ta look atthe volume per stroke This indicates what canbe lifted bout does not include the ability of the operator

Remember! Discharge values quote for treacle

‘pumps canbe miseaing Nea how ey are

‘moasured and sof thy ae sustanabie over Teng periods, blo bang ve gato statagy onthe values gen Achievable pressures

“The range of desirable features and the limits on

‘human power restrit what can be achieved in terms

‘of pressure The maximum pressure or head that can

be achieved by an operator depends on the dovenwvard Force onthe piston and its area Pressure isthe force per unit of area so fora given force, i the area is increased, the pressure decreases and vice versa A

65 kgf operator sanding on a teale immediately

ove a piston of 100 mm diameter could only

provuce a maximam pressure of 6 mbead, no mater

hos aad he tiesto push, IF the diameter sere

reduced i 75mm the maximum presse could be

inreased to 1S m hea,

Anoter and more elficient way of increasing te

pressures to increase te mechanical advantage, This

js the approach that ApproTEC and the Swiss have

used in the design of their pumps (see ApproTEC

pumps - Kenya and Swiss "conerste™ pump)

Increasing the mechanical advantage from I toon

2-100) mm diameter piston with the same 68 ke

‘operator would increase the maximum achievable

pumping pressure to 2m,

The presses quoted above ue somewhat higher

‘hun can be achieved in practice hese ae simp

{demonstration caelations based om HK) percent

font raster of force from operator to wate In

fie there ae losses Fits it ot possible in

owmal paniping situation to transfer all the bady

‘weight to cach ead: iis pethaps aly 70 percent

“tot Second, there ae Feton loses the pump

toovercome The masimuns pumping heal 34m

referred to above woul, in practice, only be Hm

presse is important, by far the Dest way oÌ

schieving isto increase the mechanical advantage

This is alaned by lower volume per stroke

When pump is is sedi must be primed This

Ssaprocess of removing al the ac fom the suction

pie and the cylinders, It this snot propery done

Fckets of ait kh in the spstem ll impair the

performance ofthe pup

Priming ean be achieved in a numberof says

The simplest way isto dra the air out by nor

pumping action, Some pumps have anon return alse

‘the entrance tothe suction pipe, sothat tdaes not

{rain shen tisnotin use, When the pump Sart p

again, is already primed and ready © go

Unfortunately very Few treadle pups have this

Feature, Another approach ist GM he pumpand the

suction pipe with water prior paring

‘Whichever way priming is achieved, the ain

“objective is 0 get al he si ut ofthe sytem, This

‘ean be difficult, because during pump start-up the

Seals ally Air eas more easily past acy seat

‘hata wet one so wetting the seals before pumping

can greatly improve priming

Small quantities of arin the cylinders can stopa

pemp from priming, particulary when the sacton

Tits high, This i hecause ar several thousand

Hw eae poops war

times move compressible than wate Dating pining,

‘ston a piston is ais lowest position, the space

‘petwovn the piston and the bottom of the eylinder

‘willbe ull far (Thomas, 1993), Ths sealed the dead space When the piston begins wo tse, the pressure below the piston falls but it does not immediaely start to suck up water Ther starts 0

‘expr ind the ar pressure drops (Boyles a pV constant) Only when the piston has moved 3

‘casiderable distance will he pressure have dred

“enough tobe below the suction pressure an soon the inlet valve to allow water into the pump,

“Thereale the piston does «use job dosing air {and below it ater) up the suet pipe This means that if there is significant volume of ir in the der shigh suction il, the operator may not beable to draw water but will simply be expanding

‘nd compressing the air inthe cylinder The operator

‘ny never be alt gt the pressure low enough to draw water,

Thispmblem is most acute during priming when the pump isd, The volume of ai relative tothe

‘wept volume ~the volume sept by the piston = can he gitehigh- For piston pups his

{exceed the volume of airs cal tothe vome

‘swept bythe piston, In such cases, st wll not be possible 1 prime the pump when the suction ead

‘excends 5 ets priming depends om keeping the ratio below T andthe suction fit as Tow as possible

Some manufactures quote operating aetna its

as high as 8 m but for many pumps it will he cally impossible to pine tem by norms)

‘ction methods at this depth, Only those puns

‘manufactredtoa very hgh standarl wil be abet scbiove this,

‘When th pump is primed and running normally the whole eylinder filled with wate andthe sels fare wet, so the air volume will disappear oF Be

‘onsiderably reduced At ths pont he phenoinero will no longer be a problem It does however highlight the problems of priming and the need for aiighe connections in the suction pipes Every litle leak ean athe problem of primi

‘the ston if the greater will be the problems of leakage

Tree any for ein i Arie

bpoeause of the uifficulty of standacdizng the power

input, which depends on the physical siengdh of

‘erator ni heirabity to sustain this power over

Period of time Comparison betwen paris from

tlferen suppliers is also made ctficul ecause af

Aitferencesin design, e.g materials use dimensions

‘of components and standards of workmanship,

“This seston reviews sever differem pumps

available in Affe, bringing together the information

svailabiontheir performance, A summary

isthen made to ry andansver the question: whichis

the bes pup? Or neve appepistely: whieh isthe

host pomp fr me? The fers she more inportant

mà depends on

tho circumstances in whl the pun wil be wed

“This will become clearer asthe review proceeds

“There are many weale pumps i se throughout

tho work, Many designs have been mesiied from

thecaly Bangladesh move tote adantageof oc

sonditons a maverias, Data te presented Here a

Six pumps = the original wreadle pump feom

Banglades, four that are boing widely usedin Ao

and econ innowation From Saszerind

© Banglades’ pumps

SADE Pusnps = Zambia

+ Masvingo pumps Zimbabwe

Enterprise Works pumps ~The Niger

© ApproTEC pumps — Kenya

*ˆ Swiss"sonerete” poms

These pumps have bem included in this re

‘necase hey were the ist real pumps on which

llth others were based, They were develope in

the late 1980s sn Bangladesh and as already

mentioned previously were called tapaktapak or TT

pips because ofthe nose they mil, The original

pups were constructed predominant trom bsibon

at the very low cost of USSS (at 1986 prices) An

improved version of this early meade pump wes

{developed inthe Palipinesy the [mematonal Rice

Research nsiute IRD which increased the pice

1 USS25 (at 1987 prices,

Several improved modes were built with wre

‘obust materials and tested in Bangladesh, Cylinder

ome ages Hones enryipenars i, wes

diameters ranged fom 76 mm 0178 sum with a Piston stroke length of approximately 290 mơ Exinsive esting was done by the Rangpur Dinajpor ura Service (RDRS) an the results published in (On et al,1991 They indicated Đạt out eor pump depended on a variety of factors, ineluding uetonif,cplinler diameter variations in ineral {rition, occasional ar eaks inthe installation, hans filters, skills and care ofthe installation team and the weight and agility of he operator

Asummaty of the text tain Table 6 shows the

hy increased discharge, The sstainahle discharge

of the larger pumps, up 10 5 lisressecond is significant hat the sho sess tha this i only achievable a very low suetion heads Only suction Ties quoted and nox pumping head, because this pump i not ñ pressure putnp and so in effet the delivery head is zero

“Thote was nandiaton ofthe piston stroke length

in these dats, Constrtion detils shows that the splinder length is 303 mm, soaseoke Feng of 290 fia heen used inca the volume of water [pumped fom each esinder por stoke, Orr defines sustainable discharge a6 the Dow praduced by two 0 thre mest weight operators pumping in shifs all day long, The authors report

‘hat higher dichargescanbesehieved using heavier

‘operators and increasing the speed ot pumping The beaver operators would beable to exploit the anger pumps that eguire more efor they Would also he able o use them at greater suctions Greater sischarges canbe expected when to people operate {pump atthe same ime, as is offen the ease in Banglades

(Onrrepored onan independent World Bank sud (gineering and power consultants, 987) that etn the effort need to work renlle pimsim terms of power input ALSO Field sites throughout Bangladesh engincers messed the power required

104896 a.redle up, sxjYesjng itn Wats over the Basic Metabolic Rate BMR) Theaverge BMR,

is 62 watts, This i the barest minimum demand,

How eae pangs wok

“Table Discharges for ferent pump elinderdameters (rel, 19) tong ginaramarinm) —

‘equivalent ying in Bed and doing pating The

resulls shoes that a comfonable pumping avy

required « power of 30 to 50 watts above BM.”

Pumping continoousy for 20 minutes aden resting

for 10 mines, healthy adult te could wrk

comfortably fot 56 hones day, So pumping ie

Second with a saction fit of m for 40 minutes in

even hour produces a average discharge of 0.65,

Jigewsecond (2.4 mM) Working at is ete for 6

hours a day would mean dat up t 14 a of water

‘ul be pumped When the suction ii ws ineease

oS mormoce, however, the average discharge fell

by 50 percent, 10 0.85 hitfes/second (1.2 m0%y),

because of the inereased etfort This eleazly

demonstrate the importance of the suction lift in

<decermining the pump discharge

‘Although Orr's report does not discuss the

cant difference between the RDRS cischrge

results and those oblsined in the Field tess, the

explanation might simply be the difference between

‘what happens inthe sboratry snd what happens ia

th eld Or does quse details Fom the Fld sty

which sesined to be que compechsnsive trom the

rasuroments taken On this ass, t would be best,

to make judgements on performance fom the field

dau, bearing in mind that more canbe achieved if

the contin are favourable

One aspect ofthe Bangladesh sation isthe

tendency fortwo operators to be working the pump

ste same time, This wouldclesly make a ference

te pump performance and would account fr some

of hehigh discharges repented Remember hat there

is iit o what an individual can achieve in terms

‘of powerontpu and therefore water itd see Homa power what ean he achieved

‘The Bangledesh design has alow mechanicat advantage beweon 8 ad 2 Generally, operators stand close to the pistons, so the piston and foot seokes are approximately the same at 2901 mm, Hiweverthe mechanical advantage range des allo for operators to ove thet position eelative fo the pivot point in order to find a more comfortable pumping postion, depending oa tbeir weight and the

‘ead an seharge required

IDE pumpr= Zambia IDE inwoduced the Bangladesh pump into Zambia

ss pant of project ta supped develop sl

se igation (see The Zambia experience oh 28), They now produce our differen ypesor weal pump the Tube well, Modified, River and Pressure Pumps to meet various needs The performance dats

‘obtained fom IDE in Zab are shoe in Table 7 {Cylinder diameter i 89 mm an stoke lenethis anpeox, 300mm tbased on the eylindr length of SIF mm, This means that the volume of water pumped pe stakes 1.78 les

“The Tube ell, Modified and River pumps as they are known, ate suction pumps tht ave been

‘mos to sit the site cenditions aroun the water ounce Toy have rwin 8mm cylinders with aspont

‘outlet on the delivery side, The pressute pump sa

‘mosifiation wo the suotion pap ha allows i 10 deliver a pressurized flow Its similar to the Biclebery pump (se Entaprise Works pups the [Nigeron p40) IDE quote range of recommend suction iftsandlscharses that canbe expected They indicate that anaverage adult can operate the pumps

Trae pops fr iergaion Africa

Figure S:IDE modMHed dưer pump, Zambla

cay for ve to six hours in a day Optimally, the

pumps discharge about 15 itzedsecond between |

Smsuction it anda maximumof2livevsecond at

Tower suction lifts, In emphasizing the importance

of the operator in achieving the desired output IDE

say thatthe pumps do become hard to operate at

suction lifts preater han 6m,

IDE recommend the pressure pump fo se only

at ow suetion lifts, between tm,

The suction pumps have a cylinder diameter of

89 mm, Assuming a stroke length of upproximately

300mm the volume of water pumped per stroke is

178 les The stroke lengths estimated from the

cplinder length of 313 mm,

“The pressure pump has a eylinder diameter of

100/mm, which inreases the volume per stroke 10

2.28 Ties Reports suggest that this pump ilficult

twoperate because of the ihiness fits eather seals

and it sometimes needs two operators t0 Work it

property Judging by the igh volume per stroke and

the small mechanical advantage it may wel be that

the pump isnot so well designed fr ths purpose i

‘only oe operators avaiable, Two operators working

Alte same time would make the pump much easier

to se, parculrly when higher pressures are needed

Operators can also mave tei postion onthe eadles

to vary the mechanical advantage but this fmited

to between 08 and 1.2

[Nomreturn valves are not ited the entrance

‘the suction pipe on the IDE pumps, so tere will be

slficulisin maintaining prime between periods of

Pump use, Priming the pressuce pump has been

describedas very cumbersome,

a

Masvinga pumps Zimbabwe

-Masvingo pumps are pressure pumps very simi

in construction to the IDE pump used in Zambia,

“The cylinder diameter is 100 mm but the eslinder length, and hence the stoke length issighly shor:

‘They are manufactured in Masvingo ~ hence the name = and several have been thoroughly tested by the Insiute of Agricultural Engineering in Harare (1988), The resulting performance data are summarized in Figure 6, The pumps are reported to

‘raducea discharge between 1-2 Ties second with

‘pump is ofthe pressure type

‘One othe main abjectives ofthe ess was tosee

‘how various pump modifications stood up 6 long

Figure 6: Pump performance data for Masvingo pump, zimbabwe

Figure 7: Masvingo treacle pump (pressure delivery),

closeup of underside

hours of use, Three types of piston and sea were

tested: leather cup with metal spacer eather eup

with a wooden spacer anda PVC end cup with two,

0" ring seals, All were tun for 800 hours and the

performance measured every 50 hours The results

showed that there was little difference in the

Aischarge-stion lit characteristics anthal his was

‘maintained over the 80 hours Differences inthe

performance of the pistons were observed however

Table 8),

Data are not available on the power inputs,

although itis assumed that only one operator was

‘sing the machine at any onetime No measurements

Ihave yet Been made-on performance inthe field

‘This pomp allows an operator to change position

and so vary the mechanical advantage between 0.8

‘and use a tread irrigation pnp pbishedin 1995

by FT Publications (sce References) The Enterprise

‘Works pumps are based on the Bangladesh model

‘but modified for pressure delivery

8 Comparative performance of diferent piston ype omen roaletem

Noma oben chanel bi ae are —

‘Shemini ahr asprin aca

aps for iergaion i rc

Figure 9

lengberg pump, Niger

‘The Bielenbere pump, named afer one of the

authors, was developed from a pump designed for

the United States Agency for International

Development (USAID) by Dan Jenkins and known

as the Universal teadle pump, This in turn was

<erived from the Bangladesh suction treadle pump

‘The early Bielenberg pumps were designed for

suction Fit a well as pressure but the publication

refered above describes only the presure version

‘They were designed for easy manulactute im small,

African workshops using commonly available

‘materials and equipment, and tobe light enough 0

be carried by one person between wells or different

fields

“Thestandad Bielenhergpurmphas cylinders with

diameter of 100 mm I canbe inexpensively rero-

fied with smaller cylinders by inserting high-

pressure PVC Finers inthe eylinders and installing

smaller diameter pistons and eather cups This makes

it easier to operate when the total pumping head

exceeds 10m,

“The pumps being use in the Niger are based on

the Bielenberg suction and pressure pump designs

Pressure pumps are not so important in the Niger,

because of the limited range of topography

Improvements have been made to the valves to

‘enhance pump operation, The suction pumps haves ron-retum valve inthe base of the eylinder and ã valve in the piston During the downward stroke, ater passes through the valve 10 fill up the space ove the piston, On the upward stoke, the water pours ove lip into canal

‘Thre 100 mm diameter eylinder models are produced: a suction pump, a pressure pump and a hhand-operated pump Alf them ean be wed by one

‘orto operators The foot and piston stoke ofthe pumps is approximately 280 mm, with mechanical advantage between 0,8 and 1.2 bu in practice most

‘operators do not use the full stoke and are most

‘comfortable using a stroke length between 150 and 200mm

Enterprise Works’ metho of testing is based on fieldrials asivis sugested that this isthe only way inhicha tue measur of sustainable output an be

‘obiained Fie testing overan extended period also allows forthe averaging othe variable power input from he operators For ths reason, Enterprise Works characterize readle pups by measuring thewverage discharge that can be susinably pưmped by an

‘operator under practical field conditions over an fextended time period, Pamp performance was measured at field sites with varying watertable depths varying suction lifts Preliminary results show that sustained discharges of 14-19 lites! second (5-7 mh) are possible with ane or wo

‘operators from waterable depths ranging from 3m

‘down to 6 m The operators can also aljust their Postion on the pump to increase the leverage and lake account ofthe increased efor needed t greater suction its,

'No measurements of maximum pressure have heen made on the pressure pumps, a this has not heen an issue inthe Niger However itis anticipated that he pressure pumps can produce total pumping head in excess of 8

Enterprise Works is developing and testing a tecale pump for use in wells where the wate evel isdeeper than 7 m below ground level, eis reported tobeableto lftupto I ielsecond (3.6) from

18 depth of 15 m I uses wo pistons lated 9m below ground level butitdoes reuire two operates,

‘A larger 150 mm diameter pump isalbo being ested, which produces a discharge of approxinatey 3 fires second (11 7a) but the suetio it needs to Be ess than 2 m, Beyond this itis reported ibe very tring

2

Figure 10: ApproTEC super Money Maker (prossuredalvery)

Pressure irigation pump

nos

Unit each nd) SAR” ute Poe

niet Pipe Rigi suction pipe

Outlet Pipe Foot valve Rubber Valve inside)

Tel ppt origin tu Atrio

ApproTEC pumps—Keayit

ApproEC, the Nuirobi-hased NGO, designs and

‘manufactures is own suction and pressure teal

pumps (see The Kenya experience These pumps

‘operate nthe same pineple as the wer pani bu

‘ere several design etre that are inifcanily

ferent, AppeaTEC sysithas looked into the ely

{designs of treadle pumps rom an engincering point

‘of view and have produce design which considers

aremore appropriate tote eoniions prevailing in

Kenya and other pats of Africa, This parieulaly

related tothe neo fr larger suction fils becatse of

the lower waterables in Kenya and the ned for

pressurized delivery systems to overcome the ralling

‘eran on many Ftms Portability is another ise

spun lt in the eld aren danger being sole,

‘One oxteome of thị redesign was» pur with

«an increased mechanical wlvantage ~up 10 4 — as

‘compared to the oer pumps hich range only

betwcen 08 and 1.2 The distance ofthe operator

From the pivot point can be as mueh as four times

the stance fom the pivot othe pistons This ans

that there is considerable leverage applied to the

istons, even by light aperatrs, The eesult i hat

Tange pressures eam be achieved, which sa desired

‘ouput for both high sti i pamps snd presse

Pips The increase in mechanical ante means

thatthe piston stroke length is sorter — 121 ra for

the suction pamp and only 73 mm fr the pressure

pump compared wih 250-300 rm froher pars

‘Thisresls in uct ess waterbeing filed per stoke

oth pumps have the same eylinder diameter, 121

rp, so the volumes per stroke are 1.32 lites and

‘hiss mean thi spare are specialist items made

‘unde factory condos, Extensive tests of both suction and presse pumps have been undertaken under controlled Taboratory conditions results are short below in Figures 12 and 13 Figure 12 shows how the ischarge varies with suction i forboth pump pes

‘Tosryandovercome he operator prblem, ests were undertaken with several ifetent operators weighing around 6Skg Each ws asked 1 pump comfortably,

ig ata pace that they could sustain for several bos, ApproTEC report that it designs thee punnps For 3 posse input of 75 wats, This is sim to Figures

“quoted aries For the per that canbe generated by

‘reasonably fit aul male buts auch higher tan the power inputs by farmers in Banglades

‘The maxim discharge is similar for both pumps reaching approximately 12 lressecond

‘when the suction ft is fess than am Ashe suction litt moreases, discharge decreases rapid

of theextr efor needed There isan interesting and onsite pin both curves hoteen 2 ad $m AS xyotthere sna physical explanation avilable fo đức Interns of practical eld aperatin, the dip is ot sient

The performance ofthe pressure pump seems ta

be slghly beer than te stetion pump, sn spite of the fact thatthe valves are more rigid than inthe sotion pump to withstand the backpressere from

Figure 12: Performance of ApproTEC pumps fora65 kg user