||bicycle powered water pump
There is a marked need for medium head, low volume pumps in underdeveloped countries. Such pumps, however, must satisfy a number of very stringent constraints due to the environment to which they are exposed. The units must be extremely low cost, ultra-reliable and almost elegantly simple. Poverty stricken cultures that possess virtually no technical skills comprise the environment for these pumps. The pumps must be rugged enough to withstand substantial physical abuse in addition to an abrasive environment. They must be simple enough in construction that local people can be dependably trained for the maintenance and operation of these units.
Cost and the need for fuel, lubricants and maintenance eliminate commercially available gasoline powered pump units. Windmills are generally too expensive as commercial units. And, they are usually too complex and fragile when built as low cost units. A particular problem for low cost units is a mechanism to accommodate high winds, their resultant speeds and loads. This leads to the simplest power source -- human power. Various schemes have been devised for producing and coupling muscle power. But, by far the most applicable, is the bicycle and the drives derived from it. This is due to the worldwide availability of low cost bicycles. It is also due to the almost unparalleled physiological coupling efficiency of the bicycle mechanism.
HISTORY OF WATER PUMPS:
The pumping of water is a basic and practical technique, far more practical than scooping it up with one's hands or lifting it in a hand-held bucket. This is true whether the water is drawn from afresh source, moved to a needed location, purified, or used for irrigation, washing, or sewage treatment, or for evacuating water from an undesirable location. Regardless of the outcome, the energy required to pump water is an extremely demanding component of water consumption. All other processes depend or benefit either from water descending from a higher elevation or some pressurized plumbing system.
The ancient concept of the aqueduct took simple and eloquent advantage of maintaining elevation of water for as long and far a distance as possible. Thus, as water moves over great distances, it retains a larger component of its kinetic energy by spending small portions of this energy flowing down a slight gradation. Granted, a useful aqueduct system ultimately depends on a fresh water source existing at a higher elevation than the location where the water can be of use. Gravity does all the work. In all other instances, pumps are necessary.
Archimedes screw, also called the Archimedean screw or screw pump, is a machine historically used for transferring water from a low laying body of water into irrigation ditches.
The invention of the water screw is credited to the Greek polymath Archimedes of Syracuse in the 3rd century BC. Its tentative attribution to the 6th century BC Babylonian king Nebuchadnezzar II by the assyriologist Dalley or to pre-Hellenistic Egypt has been refuted on the grounds of "the total lack of any literary and archaeological evidence for the existence of the water-screw before ca. 250 BC". The German engineer Konrad Kyeser, in his Bellifortis (1405), equips the Archimedes screw with a crank mechanism. This mechanism soon replaced the ancient practice of working the pipe by treading.
Archimedes' screw consists of a screw (a helical surface surrounding a central cylindrical shaft) inside a hollow pipe. The screw is turned usually by a windmill or by manual labour. As the shaft turns, the bottom end scoops up a volume of water. This water will slide up in the spiral tube, until it finally pours out from the top of the tube and feeds the irrigation systems. The screw was used mostly for draining water out of mines or other areas of low lying water.
A test pump was built on the principle of coupling a bicycle with piston powered pump where the power was taken of pedals through a chain drive to the crankshaft.
Pistons attached to the crankshaft where inserted into pvc pipe bores which cheated the required pressure for pumping water by the linear motion of the piston.
The bores where connected to the check valves for unidirectional flow of water. From this work it was observed that the model required delicate machinery of the parts and second observation was that the model had leakage and the bores and pistons where very expensive.
The linkage and the fixtures of the driving element at the pump were undesirable. Linkages where found to be undesirable due to the complexity, wear points and size. On the basis of these observations it was decided to produce a pump which was connected directly to the bicycle without removing the rear wheel of the bicycle.
A pump was built on the principle of sliding the rear wheel of the bicycle on the input shaft of the centrifugal pump. The required force to rotate the impeller is taken from the rear wheel of the bicycle which is driven through a chain drive connected to the peddle of the bicycle. This setup is mounted on a stand which holds the pump and bicycle.
By observing the disadvantages of the existing human powered water pump the proposed model has been designed and fabricated.
This model can withstand with abrasive environment, manufacturing cost of the machine is also low, about three thousand rupees. This model can be transported anywhere on the same bicycle where it is used to power the water pump so it is portable and transportable. The potential market of the machine is quite good.
In India more than 50% population are agricultural labor force. And there are approximately 100 million bicycles in India which are being used by farmers, the need for irrigation water is predicted to rise dramatically.