Control Valves Training.pdf

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FIDEC
Training Center
Control Valves
http://boilersinfo.com/
Category of Valves
Valves
Manual valves
Automated
valves
These valves are
operated
automatically.
FIDEC
(Training Center)
Modulating valves
Self Operated valves
On-Off valves
On-Off valves just put
the flow “on” or “off” .
On the other word, let
the flow medium run or
stop. There types of
valves are mainly used
for sequential control
or rough control like air
conditioning.
Self-operated valves
operate receiving
energy from fluid
pressure of fluid
temperature. It has
high responsibility
but generally is not
good at accuracy.
Modulating valves are
moreover categorized
into 2 types.
Control valves
Control valves
operate receiving
energy from
compressed air,
electric power, etc.
used with controllers
and sensors. Control
valves and related
equipment realizes
most accurate control.
Control Valves
http://boilersinfo.com/
Introduction
What Is A Control Valve?
The control valve manipulates a flowing fluid, such as gas, steam, water, or
chemical compounds, to compensate for the load disturbance and keep the
regulated process variable as close as possible to the desired set point.
The control valve assembly typically consists of the:
* Valve body
* The internal trim parts
* An actuator to provide the motive power to operate the valve
* A variety of additional valve accessories, which can include positioners,
transducers, supply pressure regulators, manual operators, snubbers, or
limit switches.
FIDEC
(Training Center)
Control Valves
training@fidec.ir
http://boilersinfo.com/
Roles of control valves
Process
parameters
Flow
Pressure
Level
Temp.
Sensor
Orifice, Flow
meter
Press.
Transmitter
Level
Transmitter
Temperature
Transmitter
Orifice
FIDEC
(Training Center)
Control Valve
Controller
4-20mA
4-20mA
D.P.
Transmitter
Control Valves
http://boilersinfo.com/
Example of process control
Flow control
FC
PC
Boiler
Boiler feed pomp
Minimum flow control valve
Level control
Reactor
LC
Heat exchanger
Turbine bypass valve
T bi b
l
Temperature control
TC
Pressure control
Boiler
FIDEC
(Training Center)
Turbine
Control Valves

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