ATM 322 – Pneumatics
Module 4
WARM
UP
VIDEO
 Explain the function of the one way flow control valve.
 Describe the main parts of the one way flow control valve.
 Adjust the one way flow control valve to the required
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actuator speed.
Explain the function of a quick exhaust valve.
Identify the main types of flow control used with double
acting cylinder
Draw the required circuit diagram that controls the speed
of the forward stroke of a double acting cylnder.
Simulate the pneumatic circuit that controls the speed of
the forward stroke of the double acting cylinder using
FluidSIM software.
Explain the difference between the one way flow control
valve and the quick exhaust valve.
Controls the flow rate in
one direction only & allows
free flow in the opposite
direction.
I.S.O Symbol
 The One way Flow Control valve consists of:
Check valve ++ Throttle valve ==
One- way FCV
If the flow is from (P) to
(A), the check valve stops
the flow passing in this
direction and the flow
then passes through the
throttle valve.
The cross-section of the
throttle is adjustable via
a regulator screw.
If the flow is in the
opposite direction
from (A) to (P), the
check valve permits
the flow freely
from (1) to (2)
• Supply Air
Throttling
• Exhaust Air
Throttling
SUPPLY AIR THROTTLING
• In the case of supply air
throttling, the one-way flow
control valves are installed
such that air being fed to
the cylinder is restricted.
• Exhaust air can escape
freely via the 5/2 way valve.
•Supply air throttling is used
for single acting cylinders
and small volume double
acting cylinders.
Control the speed of the
cylinder in the advance stroke
EXHAUST AIR FLOW
CONTROL
• In the case of exhaust air
throttling, supply air flows
freely to the cylinder and the
flow control in the exhaust
line resists the escaping air.
The piston is held between
two air cushions.
•Exhaust air throttling should
always be used for large
double acting cylinders with
long strokes. And when the
loads are not constant.
Control the speed of the
cylinder in the advance stroke
 The following items are
required to complete this
task:
1) Single acting
cylinder
2) 3/2 way valve N/C
3) One way flow
control valve
4) Pressure supply
PROCEDURES:
1-Prepare the components according to the components
list.
2- Mount all components according to the Pneumatic
circuit.
3- Connect pneumatic tubes according to the pneumatic
circuit.
4- Check all parts are connected properly with each
other.
5- Switch on the service unit.
6- Start the circuit and check the operation.
7- Turn off the service unit.
8- Dismantle and tidy up.
 In many applications especially with single
acting cylinders, it is a common practice to
increase the piston speed during retraction
of the cylinder to save the cycle time.
 This is carried out by incorporating a Quick
exhaust valve.
The Output port 2 is directly fitted on
to the working port of cylinder.
Supply port 1, is
connected to the output
of the final control
element (Directional
control valve).
The exhaust
port 3 is left
open to the
atmosphere
 Compressed air flows from
the directional control
valve to the cylinder via
the quick exhaust valve
from port (1) to port (2).
 Exhaust port 3 is closed at
this time.
 When pressure at port 1
drops, exhaust flow occurs
from port (2) to port (3).
 In order to implement
optimized quick exhaust,
the valve must be
connected directly to the
cylinder’s supply port.
 Required items for
completing this task
are:
1) Single – acting
cylinder.
2) 3/2 way valve
N\C
3) Quick exhaust
valve
Procedures:
1- Prepare the components according to the
equipments list.
2- Mount all components according to Pneumatic
circuit.
3- Connect pneumatic tubes according to the
pneumatic circuit.
4- Check all parts are connected properly with each
other.
5- Switch on the service unit.
6- Start the circuit.
7- Turn off the service unit
8- Dismantle and tidy up.
 Task Description:
A gate valve operated by
double acting cylinder is used
in controlling a filling system
for plastic pellets. The gate
valve needs to be closed
quickly during the forward
stroke of the double acting
cylinder. However, it should
be opened slowly during the
backward stroke of the
double acting cylinder. A
double pilot (memory) valve
should be used to operate
the double acting cylinder.
Task Requirements:
1. Draw pneumatic circuit diagram
2. Simulate the circuit using FluidSIM
software.
3. Assemble the circuit practically and
check its operation.
1)www.Fest-didactic.com
2)http://www.eng2all.com/vb/t289
32.html
3)http://www.logiclab.hu/lesson.ph
p?fe=2