Pumps – Operated by art device – Vehicle mounted or attached
Reexamination Certificate
1998-05-11
2001-04-03
Freay, Charles G. (Department: 3746)
Pumps
Operated by art device
Vehicle mounted or attached
C417S374000, C417S319000, C074S625000, C074S044000
Reexamination Certificate
active
06210125
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to water distribution systems, and more particularly, to water distribution systems powered by human power. The history of positive displacement reciprocating pumps goes back as far as 275 BC in Ancient Rome. In the sixteenth century, great lift and force pumps, driven by water wheels became the principle method for pumping water to be piped in Europe.
As late as 1987, the World Bank estimated that, throughout the world, 1.8 billion people would need improved water supplies, and that wells equipped with handpumps would be an appropriate choice to meet the needs of this number of people. Most of the reciprocating handpumps commonly used in developing countries have their origins in designs developed during the late 19th and early 20th Centuries in the United States and in Europe. In the United States, about 42 million handpumps were made until 1920, when electric pumps began to replace them. While the basic design of the reciprocating handpump has not changed much in this century, its typical use has changed greatly. In the early part of this century, in the United States and Europe, the big market for pumps was for small backyard pumps used for ten to thirty minutes per day by individual families or farmers. In a developing country today, a single pump may have to supply more than 500 villagers and may be in continuous operation for ten or more hours per day.
What is needed in a developing country is a manually operated pump which can be easily operated by a person for relatively long periods of time and which lifts significant volumes of water with as little effort as possible. Because of the high usage requirements, and because the pump must operate as a practical device far from cities having maintenance facilities and personnel, the pump must be both reliable and easily repaired. A handpump connected with a typical well is driven by pressing the end of a lever downward and by either pulling it upward, or permitting it to return upward due to the weight of the well. The work of lifting the water occurs as the lever is pressed downward. The simplest type of reciprocating pump is the suction pump, which draws water from shallow wells by creating a partial vacuum in a suction pipe. All of the moving parts, including a plunger moved by the lever and a suction check valve, are located above ground; only the suction pipe extends downward into the well. As the lever is pushed downward, the plunger is moved upward, lifting the water above it to be discharged through a spout, and pulling water below it upward through an open suction check valve. As the lever is moved upward, the plunger is moved downward, through the water below it, creating a pressure which opens a valve in the plunger while closing the suction check valve. Two disadvantages of this type of pump are first, it must be primed with water before it can be used and, second, the suction principle, depending on atmospheric pressure to lift water, limits the usefulness of the device to wells having depths less than about seven meters.
In deepwell reciprocating pumps, the cylinder is immersed within the well below the water level, being pulled up and down by a rod extending down the well pipe. This arrangement is suitable for wells as deep as 45 meters or more, with the operating limit depending on the effort that users are willing to apply for progressively less water at increased depths. As the depth of the well is increased, more work is required to lift the column of water in the well pipe, together with the steel rod extending down the well pipe to the cylinder.
One problem with most reciprocating pumps is caused by the fact that the lever used to operate the pump, while providing an exceedingly simple mechanism, does not make particularly good use of the ability of the human body to do mechanical work. The downward force that a person can provide to lift water in this way is limited by his own weight, and the lever primarily uses the muscles moving the arms and upper body, while, in a typical person, the muscles moving the leg are much stronger and more capable of use for extended times.
Another problem with most reciprocating pumps arises from the fact that the work of lifting the water and the pump mechanism occurs only as the lever is pushed down. For example, a conventional reciprocating pump requires a force of about 20 kg 3 as the lever is pushed down, while a force of only about 4 kg is required to move the lever back upward. Thus, uneven demands are placed on the user to supply energy to the pumping process.
A number of pump configurations have been built to overcome various of these disadvantages in the way driving forces are applied. For example, a treadle type foot pedal drive, together with a pair of flywheels, has been applied to a double piston pump, Model SB-115, produced by the Water Conservancy Bureau of Shandong Province, China. The Climax handpump, manufactured by Wildon Engineering of Worcester, United Kingdom, and the Volanta handpump, manufactured by Jensen Venneboer BV, The Netherlands, are both pumps in which a reciprocating motion is developed using a connecting rod driven by a rotating crank mounted on a shaft along with a flywheel. An eccentric rod extends from the flywheel for use as a hand crank. The Climax handpump also uses a counterweight to balance the lifting force applied through the crank.
Thus, the pump from Shandong Province, China, has the advantage of using the stronger muscles moving the legs, while the flywheels of all three of these types of pumps help to spread the force requirements over the operating cycles through the storage of energy. The counterweight of the Climax handpump provides additional help in evening torque requirements of the hand crank.
Nevertheless, the posture and leg movements of bicycle riding, which are known to be both comfortable and practical for providing mechanical work over an extended period, are not used for power input in these pumps. A bicycle type seating and pedaling arrangement is used to drive centrifugal pumps, Model 1-1/2-JB, produced by the Anyue County Farm Machinery Plant, Sichuan Province, China, and Model Jinshan-402B, produced by the Zhenjiang Sprinkler Plant, Jiangsu Province, China.
What is needed is a pump incorporating the posture and pedal configuration of a bicycle for power input with the simplicity, reliability, and flexibility of application of the reciprocating pump.
The force required to lift the water and rod mechanism of a reciprocating pump varies with the depth of the well. While the counterweight of the Climax pump attempts to balance this force, it cannot be moved to compensate for differences in well depth from one installation to another. Even within one installation, it is not unusual to increase the depth of a well to compensate for a falling water table. Therefore, what is needed is a way to vary the position of the counterweight to compensate for differences in force resulting primarily from differences in well depth.
The virtues of flywheels and of counterweighting are also discussed by S. Arlosoroff, et al., Community Water Supply The Handpump Option, (The World Bank, Washington, D.C., 1987) indicating that a properly counterbalanced flywheel in a pumping application can build up considerable speed, particularly when it is operated by two people. These editors further point out that counterweights should at least balance the pull of the pump rod and the plunger.
A conventional handpump or other reciprocating pump includes a spout extending outward and slightly downward from a point a few feet above the ground, below the point at which the pump is operated. Thus, at the spout, a rod extends upward through an opening, being attached to a lever or, in the case of the Climax and Volanta pumps, to a drive crank by means of a connecting rod. Since the top of the pump is not sealed, water cannot be raised above the spout by the pump. On the other hand, the electrically powered water pumping systems in developed countries are typically se
Eller Dana J.
Eller Daren J.
Eller James David
Evora Robert Z.
Freay Charles G.
MWI Corporation
Oltman Flynn & Kubler
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