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In this method steam is passed through a restricted passage thereby reducing its pressure across the governing valve. [2] The flow rate is controlled using a partially opened steam control valve. The reduction in pressure leads to a throttling process in which the enthalpy of steam remains constant. [1] Figure1: 2-D schematic of throttle governor
A governor, or speed limiter or controller, is a device used to measure and regulate the speed of a machine, such as an engine.. A classic example is the centrifugal governor, also known as the Watt or fly-ball governor on a reciprocating steam engine, which uses the effect of inertial force on rotating weights driven by the machine output shaft to regulate its speed by altering the input flow ...
The balls swing out as speed increases, which closes the valve, until a balance is achieved between demand and the proportional gain of the linkage and valve. A centrifugal governor is a specific type of governor with a feedback system that controls the speed of an engine by regulating the flow of fuel or working fluid, so as to maintain a near ...
Driver input switches - cruise control, idle increase /decrease, engine/exhaust brake; Injector needle movement sensor - monitors the actual injection time and feeds the information to the ECU (as used on VM Motori 2.5 and 3.1 engines) Electronic Control Unit. EDC control unit. The ECU collects and processes signals from various on-board sensors.
Two classic mechanical examples are the toilet bowl float proportioning valve and the fly-ball governor. The proportional control concept is more complex than an on–off control system such as a bi-metallic domestic thermostat, but simpler than a proportional–integral–derivative (PID) control system used in something like an automobile ...
The control action is the switching on/off of the boiler, but the controlled variable should be the building temperature, but is not because this is open-loop control of the boiler, which does not give closed-loop control of the temperature. In closed loop control, the control action from the controller is dependent on the process output.
Where a governor controls such a throttle valve, as for the Watt governor, the speed of the engine depends on a complex and unpredictable relation between the engine load, the valve position and the varying efficiency of the engine. Such governors must use a closed-loop control if they are to maintain an effective and precise regulation.
A control valve is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller. [1] This enables the direct control of flow rate and the consequential control of process quantities such as pressure , temperature , and liquid level.