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[attachment=3491]
[attachment=3492]
Components
The system comprises a Transmitter, converter module, float chamber, a feedline modulating control valve and an electronic microprocessor based PID/FUZZY controller.
Operation
A positive change of water level in the boiler alters the level transmitter inductance value of coil causing an imbalance in the system. This signal is transmitted through the electronic control box and connected to PID controller. Then the microprocessor-based PID level controller transmitted an electrical signal to the pneumatic positioner to position and adjusts the position of control valve.A additional low/high water level alarm or burner cut out contact are also provided in the microprocessor-based level controller with the adjustable setting position.
Operating principle:
Transmitter - Detect the water levels in the drum and send signal to the digital controller. Digital controller - With the signal given by the Transmitter and the controller will show the level on the meter (Process value) and it requite a Set Value to control the level. The signal converted and it sends to control valve to give an indication.
Control Valve - The control valve work depend on the signal given by controller and after done the job it send a feed back signal to controller for confirmation. The valve open is depending on supply air with the signal given by controller and the Positioner then adjustment opening of valve will be make.
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06-06-2010, 12:51 AM
please could you send to me this poject because I need it
Thank you
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BOILER CONTROL SYSTEMS
TYPES OF CONTROLS:
Control systems may be pneumatic, analog, digital, or a
combination of the three.The present industry standard is for a
distributed control system (DCS), a programmable logic controller (PLC), or a direct
digital controller (DDC). These work based on the information gathered from sensors.
CONTROL SELECTION:
-Microprocessor digital type of controls (e.g. PLC, DDC, or DCS) are used where a large number of control loops are involved.
-Pneumatic control devices should be used in hazardous areas
-Analog logic devices are outdated.
Boiler level control system
a system for controlling the fluid level in a boiler drum has been described here. a feedwater controller is described where the steam flow measurement and water flow measurement are not recognized if they attained the equilibrium condition. the controller provides an improved response in attaining drum level equal to drum level set point. the feedwater control valve (FWCV) controls the level of water in the boiler drum in accordance with a signal output from a control station. Three-element control scheme is implemented. It can maintain water-flow input equal to feedwater demand. The Actual drum level (DL) is sensed by a level transmitter which is then subtracted from a drum level set point (DLSP) as determined by the plant operator.proportional K plus integral action is applied to the error between the drum level and its set point. The summation of the drum level error signal and the steam flow signal becomes the feedwater-demand signal.
for more details, refer this link:
http://freepatentsonline4242989.html
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