HOW TO CONTROL WATER LEVEL IN BOILER // THREE ELEMENTS CONTROLLER // TWO ELEMENT //SINGLE ELEMENTS

THREE ELEMENTS CONTROL SYSTEM l: Disturbances in drum level are caused by fluctuations in main steam flow. Figure 1 shows a typical drum level controller, which measures the drum level (1), main steam flow (2), and feedwater flow (3) and manipulates the feedwater control valve to regulate the drum level. This is three-element control. This three-element controller is a so-called cascade controller in which a drum level control unit is cascaded into a feedwater flow control unit. Single-element Control: During startup of a boiler, both the feedwater and main steam flow rates remain below the measurable ranges, and this makes the three-element control with a level controller and flow controller unstable. In such cases, it is effective to use single-element control in which the feedwater controller is bypassed and the drum level controller directly controls the feedwater control valve. More videos for BOILER OPERATION AND BOE EXAM PREPARATION    • BOILER Operations And BOE exam Preparation   for FITTER TURNER WELDER DIESEL MECHANIC THOERY AND OBJECTIVES    • Fitter theory and MCQ online      • FITTER MCQ