ong>Answer:

WATER LIFTING DEVICES

According to power sources water lifts can be classified as manual, animal and power

operated devices. The brief description of these devices is as under:

Human Powered Devices

Man has a limited physical power output, which may be in the range of 0.08 to 0.1 hp. This

power can be used to lift water from shallow depths for irrigation. The common man powered

devices are:

1. Swing BASKET. The device consists of a basket made from the cheap materials like

woven bamboo strips, leather, or iron sheet to which four ROPES are attached. Two persons

hold the basket FACING towards each others, dip the basket in water source and by swinging,

the basket is lifted and filled in water course from where the water flows to the fields. The

device ~s useful up to a depth of O. 15m and discharge may vary from 3500 to 5000 l/h.

2. Counterpoise lift. It is also known as dhenk/i or picattach. It is generally used for

lifting of water from unlined wells, stream or pond for irrigating small fields. It consists of a

lever rod supported at a suitable point on a vertical post about which it can swing in vertical

DIRECTION. About 2000 1itres of water can be lifted from the depth of2 to 3 metres in one hour.

3. Don. The principle of operation of don is similar to counterpoise lift. The don consists

of a trough made from wooden log or iron sheet; closed at one end and open at the other. The

open end of the trough is connected to a hinged pole with a counter weight through rope. For

operation the trough is lowered by exerting pressure on it by pulling the rope and also by foot

of the operator till the closed end is submerged in water. Upon releasing pressure the trough

comes to its original position due to action of counter weight along with water. Water can be

lifted from this device from a depth of 0.8 to 1.2m.

4. Archimedean screw. It consists of a helical screw mounted on spindle, which is

rotated inside a wooden or metallic cylinder. One end of the cylinder remains submerged in

water and is placed in inclined position at an angle of 30 degrees. It is used for lifting of water

from a depth of 0.6 to 1.2 meters and may discharge 1600 1itres per hour.

5. Paddle wheel. It is also known as Chakram and is mostly used in costal regions for

irrigating paddy fields. It consists of small PADDLES mounted radially to a horizontal shaft,

which moves in close fitting concave trough, thereby pushing water ahead of them. The

number of blades depends on the size of wheel, which may be 8 for 1.2m and up to 24 for 3 to

3.6m diameters. The wheel having 12 blades may lift about 18000 litres per hour from a depth

of 0.45 to 0.6m.

Animal Powered Devices

Animal power is abundantly available in India. They are used for lifting of water, besides

other field operations and processing works. A pair of bullocks may develop approximately

0.80 horsepower. They can Ii ft water from the depth of 30m or more. Of course the rate of

discharge will go down with increase in lift. Some of the devices used for irrigation operated

by animal power are as under.

I. Rope-aDd-bucket lift: Also known as Mote. Charsa or Pur it is used to lift water from

lined wells up to a depth of 30m. The device consists of a bucket or bag made of GI sheet or

leather, and pulley arrangement. A rope is attached to the bucket-or bag, which passes over a

pulley and finally fixed to the yoke of bullocks. The bullocks walk down on an earthen ramp

sloped at an angle of 5-10 degrees to lift the water. About 9000 1itres of water can be lifted