24. AIR FLOW MEASURED BY USING AEROFOIL WHOSE DIFFERENTIAL PRESSURE IS SENSED BY THE AIR FLOW TRANSMITTER SQ. ROOTED IS COMPENSATED TO THE AIR TEMPERATURE AT FUNCTION BLOCK. THE COMPENSATED AIR FLOW ACTS AS PROCESS VARIABLE TO. THE OUTPUT OF FIC POSITIONS THE FD FAN DAMPER ACTUATOR
27. HERE S.H I STAGE ‘TIC’ ACTS AS A FEED FORWARD CONTROLLER. ‘TI’ FIRST SENSES ANY VARIATION IN TEMPERATURE AND ‘TIC’ TAKES THE CORRECTIVE ACTION. WHATEVER DEVIATION IS PASSED ON TO, IS SENSED BY I STAGE & II STAGE ’TE’s AND II STAGE ‘TIC’ WILL TAKE THE CORRECTIVE ACTION BY CHANGING THE OUT PUT,- - THAT GOES AS REMOTE SETPOINT TO I STAGE S.H.‘TIC’ WHICH FURTHER CORRECTS THE TEMPERATURE.
28. THE TRANSFER SWITCH WHEN SELECTED, ENABLES THE OUTPUT OF T.I.C - -TO TRACK THE SIGNAL WHEN THE S.H. OUT LET TEMP. IS < THAN THE RATED TEMPERATURE, SO AS TO AVOID TIC SIGNAL GOING >100%. THE FEED WATER FLOW FOR ATTEMPERATION IS MEASURED & INDICATED IN ‘FI’. THE TOTALISER ‘FQ’ INDICATES THE TOTALISED FLOW.
29.
30. Deaerator Pressure & Level Control THE CONTENT OF DISSOLVED OXYGEN IN FEED WATER ESCAPES DURING BOILING AND OXEDISES /RUSTS THE INNER WALLS OF BOILER TUBES AND DRUMS. TO REMOVE THIS ‘ O 2 ’, WATER IS BOILED IN THE DEAIRATOR BEFORE FEEDING IN TO BOILER.
37. ECONOMY AND SAFETY OFA NATION MUCH DEPENDS UPON GOOD MEASURING AND MONITORING SYSTEM IT EMPLOYS. Have a measure 0n every step To have total control On our target