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DEVELOPMENT TECHNOLOGY UNIT Working Paper No. 34 The Treadle Pump 1991 Development Technology Unit Department of Engineering, University of Warwick Coventry CV47AL UK, Tels +44 (0)203 £23573 extn 2339 Foe: (203-418922 Telex: 311904 UNIVWK G THE TREADLEPUMP ‘A homan-powered pump for saalt-seale irigalion Poe Developing Counties DTU Working Paper 24 prepared for The Ramat- Warwick Linkage Programme, Sub-Prograraran 4 ‘under the North ast Ard Zone Develapa.ent Progeamme ‘Boma State, Niger “Tae Development Technology Unit, Department of Engineerieg ‘University of Warwick, Coventry, CV4 TAL, THK. SUMMARY Using a eadlepa tof water to a heightof 5 metres ii postbie fora farmer to gate approeamately 0.23 bectaes of Lind: the pump can be used for onp periods of ue because oF soot ergonomic design. The costo dontrction is iow andthe Dap can provide an appropri technology for amallnoders with Tinie cpa fo spend on igo ‘THE TREADLEPUMP A human-powered pump for small-scate irrigation in Developing Countries page SUMMARY 1.0 INTRODUCTION 1 20 THE NEED POR TREADLEPUMPS- A comparison of pumping 2 ‘technologies for small-scale iripaion 3.0 TREADLEPUMPS- A description 3 3.1 Pomp Cylinders 3 32 Pump Manifold a 33 Nonsrecum Vatves a 34 Piston Assembly 5 35 Treadles 5 36 Pulley Wheel 5 37 Frame 5 38 Summary of Treadlepump Components 7 40 THE ERGONOMICS OF TREADLEPUMPS 7 41 Ciilising Human Power 1 42° Stole Length 7 43° Cadence 8 44 Foot Force 8 43 Mechanical Advantage a 46 Treadle Spacing 3 47 Summary of Frgonomic Features 5.0. AVAILABLE DESIGNS OF TREADLEPUMPS 10 $1 The Bellow pump, Philippine 19 52 ‘The Tapak-Tapak, Bargladesh 2 33 The USAI mreadiepamp, lary Const 4 $14 The Harare readleporap. Zimbabwe 18 33 The Warwick tesdlepump, (Nigeriay 18 60. THE WARWICK TRFADLEPUMP- The neod for anew design 2 6.1 ‘Table of Specification: The Warwick Treilepump % 62 Stamus of the Warwick Treadlepump 7 BIBLIOGRAPHY 2” APPENDIX A Drawings of the Warwick mesdleparap with ‘constractian noes 29 APPENDIX B The Treadleptasp for North Homo State, Nigeria 2 19 INTRODICTION ‘This repact has heen prepared hy the Development Technology Unit cf the University of ‘Warwick, Caventry, CK. [Cis part of the studies carried out under an EEC funded linkage programme between the University of Warwick and Ramat Polytechnic, Bono State, Nigeria. ‘Tar linkage isa sub-pmgramme of the North East Arid Zone Development Programne (NFAZDP) which ell seeks to promote the development of rural people in the region and romoue long-term sustainability ‘The subject this enor is teadlepumps and their use for small-scale inigation in Developing Connrries. The readlepump isa human-powered water pump that can lift irigation water from, grourd or surface sources. ‘The pumtp consists of two pumping cylinders that are worked Frcipreeally by the action af the operator sanding on two teadle bars. This system gives a near ‘ponstant flow of watee and a comfortable pumping actior. forthe user, The design of the pump allows operators to shift theteposicion along the treadles und so vary ie feroe on the cylinders ‘thie way a range of pumping heats can be achieved “The principle advantage of the meadlepump over other forms of human-powered water pump i that it makes hest use of tbe muscles of the body: The treaule action uses the large muscles of the leps, buttocks, and back. This allows ausiained use of the pump and the paroping of large volumes of water that are needed for imation, ‘Tete are curently several designs of teadlepamp produced, and a section of the report details thei principal features, strengths, and weaknesses. For interested patics there are conuact ‘addresses for all the prups described. ‘The mport goes an to describe why it was thought valuable to develop a new design 00 cater the special needs of African counmies. The result was the Warwick teadlepumnp and the original design specification is included with a discussion af the pump’s construction and performance. ‘Complete constuction details of the Warwick weudlepump. engineering drawings and aotes, are given inn appendux. A second appendix discusses the use of the teadiepump inthe context of Homo Siate, Nigeria 20 THE NFED FOR TRRADIFPUMPS: 8 Comparisan of Punnpiag Techaniogies for Developing Countries ‘As the haman population increases at an ever faster rate the need for increased food praductan is ‘presting. ‘Tae greatest need jz in Daveloping Counisies where populations are groving fastest fand the land availabe for the growth of saple crops ix shrinkiag, One of the best ways this can be achieved is by making appropriate irigation technology availabe to che small fanmer. Tn Developing Countries much ofthe land is famity-owned in small pls. Ibis not uncommon for the majority af farming land ta be owiaed in units of less chan 2 hectares. These small lows are often worked solely by the cers and their families. and extemal inputs, inthe form of ‘mectanisation and feruliser, ae Tow. “The wy to increased prodaction has often been seen through incorporating smallholdings inte larger unit and iuroducing mechanization and large-scale erigation. ‘This approach, while seezesh carly hgh out olen pendoes many pblems he di a oo {odigeoous farming methods salizaton, lari-panning, and loss offer. Often this Qe of farming proves to be fess efficient than tadiiona maths. ‘Modern thinking for the development of aericultura! production in Developing Counmrics looks to retain the taditional cwnership ofthe land and suppor: the indigenous farmer by providing educational aed appropriate technica! Suppor. Irrigation is ane ofthe principle ways to increase production in agriculture elher by extending the growing seacnn on existing land or by bringing fureher land into production. Providing small farmers with ivigation water from lagge Schemes can be very expensive: The cost of civil engineering works must be subsidised by the goverument, cr another agony, as the cost is ‘heyond the reach of the rural poor. ‘The collection of water fees from s large mumbec of users is also dificalt. Such schemes often achieve only low efficiencies (high water wastage). ‘Tae aleraiive fs small scale imigarion uxing appropriate, locally maintzinable technology this directly conteclled by the farmer, As a stabhelder can only afford a small capital sum ard [ow runeing cons the options for technological inputs are mite. A Tow init cost eliminates the the of a renewable energy such as solar ot wind evea though these technologies offer very 1Ow ‘ots ia the long ten. The cost of petrol of diesel engines is alsa high snd although fuel is cheap inne counties sch at Maes seppl cap be uncer an pce eo a ae, Ds cxpersive, at Worst unobtainable. This leaves the use of animal oc human labour for wale [Pomping acGviien. In areas where daft animals ae already used animal power is a good option, Fioweverif the animal cused solely tor iigation sctivides its unlikely at the extra rea sained ic sufficient to justly the expense of keeping the animal. In this case joint ownership ‘would seem tobe the answer bur this brings wih ita furher set of problems rezaing ‘he Upkeep ofthe ania. Human (abour on the other hand can be used for irigacion when not covapied with other tasks, and although the power ouput of @ human is low, when compared i other energy sources. the farmer can decide exactly when and how sauch to iigate the fields. This level of control given to the farmer can significantly inctease yields. For these reasons sniall, human-powered water pumps for irrigation are very uscful to the snualtholder with few resources. Pampes that can be operated und maintsined at village level alo have the advantage reducing the dependence of farmers on outside support services and increasing their self reliance. ‘The meadlepump is designed with these criteria in find and as will be thown ia Secon 40 nukes best we of te apubis ofthe aman bay n providing per for water pumping. 30 TREADLEPUMPS- A Description “Toe sadlesump jew human-powered water pump tha sued principally for gai stalloldings of land. in forms waters ppd by twa dueetlsplacement isons ‘wich ae operted reciprocally bythe wallan/sepping maton of ie use ‘A general layout of ke weadlepump is shown in Fig 3.1. The rage of wendlepump designs can fe Spit ins two groupe Those tat wilt water from lower evel to the hight of te pu and hose that wl bath ch water om at Tower level und ir fre ow grester eight un te amp hee ores canbe dee as ston pomp, sd usin nd eae pap enpecively. ‘The besic components of any eadlepump are described below 34 Pump Cylinders “Theo pumping cylinder re operated reciprowally and ive amet continoons ow of wate. Depending ou the operating feu te diameter of ie pup cynders fs normaly between ?Snzz ((orhigh heads) an 150mm Gorlow hewis) most ofen 190mm diameter is chosen. & eyinder Gmc of {Oban sseabie for pomping water to heal of betwuer 9 ad Sin Sins nr ay const uo tp pe. Chie oat pgs Sup dae sec nbs Bee Gee of at Sey reso pai a Sl al Ge te an spl mehnen ia pe nmr ple pecan Hanon lay pl pon air ie rag fmartand HELLO GEISER ay See pul lest q 32 Pump Manifoid ‘The manifold vonnects the inlet and outlet pipes tothe eylinders (in a stetion pump :tis not necessary). Itis separated into tw: water enters the pump atthe cutry side of tre manifold, arc se ashing tou ihe ylides, Tevet onthe discharge sie, The warfold nomally houses the non-return valves which prevent backflow in the pump. ‘The manifold vn be constructed from sicel sheet welded into the form of a box. or nove easly. in pump with pvc cylinders, from pipe fing or straight pipe. ‘The design of the nnifsld must allow forthe removal of the adn-retum valves for enanienince, 33 Non-Rewar Valves In a suction only punmp the non-resnra valves ace sitsated inthe piston heads and inthe inlet pipe. Ina suction and pressure pump there ae fw pairs, one on the inet side of the pump and one on Ue oullel, The valves allow waler fo aavel rough the pump but prevent its backflow to the source, The valves open and clase due to the positive and negative pressures developed during. pumping, ‘Various types of nen-rebura valve are usod in teadlepuanp designs, these include mubber faps, swinging £488, and poppe! valves, ‘The Warwick design uses a new type of valve that ces on the steithing ofa rubber flap over a patter of Boles and is unique in ari involves no moving, pas, FIGURE 2.1 Main Components of the Treadlegunp See 344 Piguom Aspemsbly, ‘The pistons are driven up and down within the cytinders by the weight of the operator on the uweadies. The piston tod is connected (othe readies by a hinge that allows the piston to sty veréval in the cylinder as the teadles are moved up and down, This is important to maintain a {ood seal between the piston cupsand the cylinder ‘The piston rods are normally of round stee! bar and are threaded at ane end to atach the piston cups or rings. The piston cups can be made of rubber or feather but must provide a good water Sealand sustain the rigours of coaviaual ftiedion against the cytinder wall. 35 Treadles ‘The pum operator stands oa the teadles and pushes thems up and down to work the pump. They sare formally binged at one end but ia one bazaboo version the hinge is between the cylinders sna the operator. Atthe opposite end, ie teadles are supported by a pulley wheel and rope ora bar. The range of movement is dictated hy the stroke length ofthe pistons ed enn ‘zaportantly by the confortable operaciag step ofthe operator, ‘The readles can be made fom wood. bamboo, of steel. Steel is only normally used when the ‘reales are lo be cranked 1o bring the cperater closer 6 the graurel 36 Pulley Wheel ‘The pulley wheel allows the cylinders to move reciprocally and so provides # natural operning syle for the user. ‘The wheel has a centra: axle mounted to a framet a simple axle, such a5 a ‘6mm diameter bot, s normally used. ‘The wheel can be made from hard woot and boiling the ‘wheel in oil reales the wood ane lubricates the bearing for a substantial cime, ‘An ahernative to the whee! is a rocking bar which is pivate in the midlcle. This rangement is ‘harder to balance bat miay be eatier © construct in same instances, 37 Fraime ‘The compotent parts of the treadlepump are mounted ona frame or in sorne designs buried in the wpound. A amt ows he pum io ecard te where its mont med Alhngh an xpentive part of the pump, portability adds significantly to its value inirsigation. Angle icon or box section are mast often used (9 make a frame thas wil stand the weight of the ber und the rigours of ransportacion, Hf the pump does not need to maved regularly it may be acceptaie to dispense withthe frame and support the weadle hinges and the pulley shel on sakes knipcked inta the growed. This sell reduce the cost of the pump. in Bangladesh the Tapak-Tapak pump uses this setup but it ix ‘hat the pump is caried back to the house each wight for secarity, obvinusly hore the ark of a frome has 10t stopped the punsp being portable! 32 Snmmiry of Tradleponp Components the pats just described ae well designed and matched, she pump will operate smootkly and ‘efficiently, Tes end this section here isan stempt tn describe the action of powering the trea leparip: ‘The mation af the operator's legs ont the treailes is simiar toa combination of walking on the ‘spot and of climbing 2 ladder. Operators can become accuscorsed to this movement very quickly and in 4 well designed pomp wil find chat it ean be sustained for several hours a day with, appropriate ress. A folldeserigeicm of the ergancrtic design af the pump is given ie Section 4.0.