Nadhi Koratagere
Unit 12: Pneumatic and Hydraulic
Systems
Nadhi Koratagere
Develop pneumatic and hydraulic
circuit diagrams and simulate their
operation.
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Contents Page
Introduction – Page 3
Basic Pneumatic System- Page 3
Automated Circuit- Page 6
Pneumatic Circuit- Page 7
Iterative Process For Pneumatic Circuits-
Page 8
Hydraulic Circuits- Page 11
Introduction
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I will be drawing up circuit diagrams for a pneumatic
and hydraulic circuit using Automation Studios. This will
enable the operation the new circuits to be simulated
and refined. I will be making changes to the
components and system parameters and I will refine
the output characteristics of each circuit in order for
them to match the client brief.
Basic Pneumatic Circuit
Systems
What is Pneumatics- Pneumatics is the use of gas or
pressurized air in mechanical systems
Double Acting Cylinder
5/2 Directional Control Valves
3/2 Directional Control Valves
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manual operated double acting cylinder circuit uses manual controls to move a
piston in both directions. The circuit is made of many different components
which work together to carry out the function.
The components Include:
A Double Acting Cylinder: A double acting cylinder is a cylinder which has
two ports, ones for pushing the piston out and then one for brining the
piston back in
Directional Control Valves (3/2 and 5/2)
A manually operated double acting cylinder circuit works by using directional
control valves to direct pressurized air to either side of the cylinder which
allows it to expand and retract in both directions. The valve will be controlled
by manual actuators such as push buttons or levers. When one button is
pressed, the air will start to flow into one side of the cylinder which will cause
it to expand. By pressing the opposite button this will reverse the airflow and
therefore cause the cylinder to retract.
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Automated Circuits
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Above shows an automated pneumatic circuit which uses a 5/2 valve and two 3/2
valves. Compressed air is supplied to the system and is then routed around
based off different given signals. When the 3/2 valve is in use this then sends a
signal to the 5/2 valve which then causes it to shift and this allows direct air to
flow into the left side of the cylinder which expands it. As the cylinder starts to
reach its full expansion it then signals the 3/2 valve which then sends another
signal to the 5/2 valve which reverses the airflow and retracts the cylinder.
Pneumatic Circuit
Testing for cylinder 1.5
The circuit below is designed to transport a part from one level to another
which uses the cylinder 1.50 and then onto a separate conveyor system
using cylinder 1.70.
I am making suitable adjustments to the circuit so that the cylinder 1.50
extends in a time of 3 seconds and retracts in a quick but controlled
manner which is ready to receive the next part. Cylinder 1.70 moves the
part in a time of 1.50 seconds and then retracts in a controlled manner.
The whole operation then takes place in a time less than 15 seconds. I
have used a tolerance of 5% for all the timings.
I then recorded the results of the circuit optimisation in the table which is
shown below to show the iterative process that I have used in order to
achieve the outcome which is suggested
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This is a pneumatic circuit which has two double acting cylinders. The
circuit uses both 5/2 and 3/2 valves.
Air enters via the pneumatic pressure source; the compressed air then
starts to flow into the 3/2 way normally closed valve which in this case has
been left permanently open by a switch. The circuit begins when the
cylinder 1.50 expands due to the valve to ensure it completes it circuit in
exactly 3 seconds. Once the piston is fully extended the mechanical
sensor then sends a signal which triggers cylinder 1.70 causing it to
expand and moving the part sideways within the 1.5 seconds. Both
cylinders then retract. The movement of the cylinders is organised by the
sensor and the valves. The overall design of the circuit is that it repeats
consistently within the 15 seconds.
Iterative Process for
Pneumatic Circuit
Iterative Process Definition: The iterative process is a method of
adjustment. It involves repeatedly testing the circuit and recording results
and then making minor changes such as changing different values. This
process is commonly used in pneumatic and automated systems as timing
and sequences of the operations are highly important.
Test Results for cylinder 1.50:
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Test Orifice Size (mm) Time to extend (S)
1 5.00 00.237
2 1.00 00.447
3 0.50 01.658
4 0.25 04.76
5 0.30 03.632
6 0.33 03.02
After doing 6 tests, the double acting cylinder piston 1.50 will have an extension
speed of 03.02 seconds and the orifice size is 0.33mm. As stated within the
client brief this is within the 5% tolerance.
I used this feature to
add in the lines
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Test Results for cylinder 1.70
Test Orifice Size (mm) Time to extend (S)
1 1 0.21
2 0.5 0.27
3 0.25 6.97
4 0.45 2
5 0.53 1.52
After doing 5 tests, the double acting cylinder piston 1.70 will have an extension
speed of 1.52 seconds and the orifice size is 0.53mm. As stated within the client
brief this is within the 5% tolerance. I have used the yt plotter to find this out by
changing the dimensions on the throttle valve.
Hydraulic Circuit
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For the hydraulic circuit I need to make suitable adjustments to the circuit so
that the rotary actuator has a rotational speed of 50RPM. I will then record the
results of the circuit optimisation o show the iterative process that is used in
order to achieve the outcome suggested
above.
Above shows the hydraulic circuit. At the bottom of the circuit shows a BOM
which has the listed components. The hydraulic circuit operates via the use of a
double acting cylinder and a hydraulic motor using directional control valves it is
powered by a unidirectional pump from a hydraulic reservoir. The system begins
at the pump which then pushes the pressurised hydraulic fluid through the circuit
at the 80.3 bar. The flow first passes through the valve which will help prevent
overpressure. When the valve connected to the cylinder is in use the fluid flows
into one side of the double acting cylinder which then causes the cylinder to
expand and retract depending on the position of the valve. The second valve
then controls the fluid flow to the hydraulic motor which allows it to rotate at a
speed of 50 RPM when engaged.
Iterative test:
Test Displacement (cm3/rev) Revolutions per Minute
(RPM)
1 310.00 -5.2
2 312.00 -3.1
3 312.25 -3.6
4 315.00 45
5 315.10 48.3
6 315.20 50.5
315.19 50
From the iterative testing that I have conducted I have managed to get a RPM of
50 by changing the displacement to the suitable measurement.
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