Updated on 18/6/2015
Basic Principle Of Fluid Amplifier
Basic Principle Of Fluid Amplifier
Most popular application of fluidics
is amplifiers. A fluid amplifier is basically a flat piece of metal or plastic
in which shallow passages are engraved for the flow of fluid.
The
arrangement of these passages differs for each type of fluid amplifiers, but in
principle all the amplifiers have a main power stream, which changes its
direction of control jet.
The tendency of fluid to chose one
side of a symmetrically diverging channel and flow in an asymmetric way is
called “Conda effect” in honor of the first man (in 1930’s) to observe and
utilize the phenomenon. Subsequent work has shown that, if symmetrically placed
splitter is very close to the entrance part of the main power jet, then this
jet is divided equally in both channels.
Fluid
Amplification
Amplification function can be achieved
by employing fluid amplifier. The amplifiers may be electronic or fluidic.
Amplifier is a device which gives a large change in output of either pressure
or both as a result of small change in control input. In other words we can say
that amplifies its input signals.
Generally amplifiers
are of following types.
1. Digital amplifiers
2. Analogue amplifiers
Timing
This
method is used to blow the whistle at pre adjusted time and employs NOT-AND
logic functions.
Supply
tubes are counted to the clock from the rear at 12 points (at 5 minute
intervals). The output tubes are fixed in the clock glass exactly opposite to
the supply tubes. The minute hand moved in the gap between these supply tubes
and output tubes. These minute hands interrupt the passage of the jet.
Air
is supplied to all the 12 supply tubes and to any one of the output tubes. The
output tube is connected to the NOT element through a flexible pipe. In the
normal position (when minute hand is not interrupting the jet) input signal
remains on’ which results switching off the output. Thus the NOT element
normally remains ‘off’ and it starts when the minute hand interrupts the air
system.
When
the lever valve is on position and supply from it is on, AND element will not
operates until NOT elements also supplies the output as shown in the figure.
Thus when both signals are supplied (i.e. at the point when minute hand
interrupts the air system) the AND unit will operate the step up relay which
then blow the whistle.
Thus
the whistle can be blow at any preset time, by providing the interruptible jet
at that particular position on the dial. Timing –with the minute hand
interrupting the jet, output tube at 3 (at 15 minute position) and lower valve
is in on position, AND function is complete, whistle is blowing.
Logical Function NOT
This
logic function can also be achieved by employing one turbulent amplifier. If
one input signal is used, the result is NOT i.e. No output will be available.
This is also known as ‘signal inversion’.
Logical Function
OR
This
logic function can be achieved by two turbulent amplifiers. If an input signal
either A or B or C or D is applied to turbulent amplifier X, then output from
this amplifier will be off. As shown in figure this will cause the input signal
E to turbulent amplifier T to be off. This will result in output from the
amplifier.
Applications
2. Industrial application:-Sewing machine
control.
3. Marine application:-Turbine speed
sensors.
4. Medical application: - Artificial heart
and lung ventilators.
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