This document outlines various hydraulic devices: hydraulic couplings transfer power between shafts using oil; torque converters multiply torque using guide vanes; hydraulic rams use water hammer to pump water to higher elevations; accumulators store hydraulic fluid under pressure to smooth demand; and jacks lift heavy objects using hydraulic force.

1. Fluid Mechanics II
Muhammad Usman

2. Outline
• Hydraulic Coupling
• Hydraulic Torque Converter
• Hydraulic RAM
• Hydraulic Accumulator
• Hydraulic Jack

3. Hydraulic Coupling
• It is a device to transfer torque or power
from one shaft to another with the help of
an oil which acts as a working medium.
• The speed of the driven shaft is always
less than the driving shaft by 2 to 4
percent.
• Used in diesel locomotives, and
automotive industry.

4. Hydraulic Coupling

5. Hydraulic Torque Converter
• A hydraulic torque converter is the
improved form of the hydraulic coupling, in
which guide ring consists of series of
guide vanes whose function is to change
the direction of the oil reacts upon the
turbine runner which multiplies the torque.

6. Water Hammer
• Water hammer (or, more generally, fluid
hammer) is a pressure surge or wave resulting
when a fluid (usually a liquid but sometimes also
a gas) in motion is forced to stop or change
direction suddenly (momentum change). Water
hammer commonly occurs when a valve is
closed suddenly at an end of a pipeline system,
and a pressure wave propagates in the pipe. It
may also be known as hydraulic shock.

7. Hydraulic Ram
• A hydraulic ram, or hydram, is a cyclic water
pump powered by hydropower. It functions as a
hydraulic transformer that takes in water at one
"hydraulic head" (pressure) and flow-rate, and outputs
water at a higher hydraulic-head and lower flow-rate. The
device uses the water hammer effect to develop
pressure that allows a portion of the input water that
powers the pump to be lifted to a point higher than where
the water originally started. The hydraulic ram is
sometimes used in remote areas, where there is both a
source of low-head hydropower, and a need for pumping
water to a destination higher in elevation than the
source. In this situation, the ram is often useful, since it
requires no outside source of power other than
the kinetic energy of water

8. • Water is run into a feed pipe (with a screen to keep out debris) from a
river or stream. As the water runs down the pipe it picks up speed
and, therefore, momentum. As the flow builds up to a fast rate, it
overcomes the mechanical spring pressure on the main valve,
causing the valve to close. This stops the flow of water through the
feed pipe, but since it has built up momentum, the pressure inside the
pump increases. This forces water through the check valve which
then momentarily compresses the air in the air chamber. The air then
decompresses, pushing the water through and out of the delivery
pipe, while the check valve prevents water from moving backwards
through the pump. As the water flows through the delivery pipe and
out of the pump, the pressure inside the pump drops, allowing the
main valve to open again. This allows the water in the feed pipe to
begin flowing again, starting the cycle all over again.
• All that is required to make a pump like this function is a minimum of
about two feet of drop in the feed pipe, although more drop is
desirable as it provides increased flow rates and greater maximum
delivery heights.

9. Hydraulic Ram

10. Hydraulic Accumulator
• A hydraulic accumulator is a device used to
store energy. It holds a hydraulic fluid that
cannot be compressed under pressure through
an external source. The external source may be
a raised weight, a spring or a gas that is
compressed. The major reason for the use of an
accumulator in hydraulic systems is to ensure
that the pump is not too large to handle the extra
demand. In this way, the supply circuit is able to
respond faster to smooth pulsations and to
temporary demand.

11. Hydraulic Accumulator

12. Hydrulic Accumulator
• An accumulator installed in line will protect
the valves, gaskets, pressure guages.
• Common applications are found in
refineries and pipelines.

13. Hydraulic Jack

14. Hydraulic Jack
• Hydraulic jacks are used in industry to lift
heavy objects. Their most well known
application is raising and supporting an
automobile to facilitate the replacement of
a flat tire. They may also be found at work
in a variety of specialized applications,
including lifting airplanes, race cars, semi-
trucks