Abstract: A surge control system (16) is provided for a compressor (14) which anticipates the actual surge condition and initiates anti-surge protection in proportion to the magnitude of the anticipated surge condition. This is done by providing a feed forward signal (20) to a summing station (48) along with a normally generated surge control line point (44) to offset this point (44) by an amount determined by the feed forward signal (20). This offset point (50) is used as an input to a controller for controlling the bypass valve (28) in a bypass loop (30) around the compressor (14).

Abstract: A surge control system (16) is provided for a compressor (14) which anticipates the actual surge condition and initiates anti-surge protection in proportion to the magnitude of the anticipated surge condition. This is done by providing a feed foward signal (20) to a summing station (48) along with a normally generated surge control line point (44) to offset this point (44) by an amount determined by the feed forward signal (20). This offset point (50) is used as an input to a controller for controlling the bypass valve (28) in a bypass loop (30) around the compressor (14).

Abstract: A control system for a heat exchanger, such as a superheater in a fossil fuel fired steam generator, uses a multivariable non-linear regression equation to develop a feed forward signal that continuously adapts itself to changes in system variables to adjust the enthalpy of the steam entering the superheater and maintain a substantially constant enthalpy of the steam discharged from the superheater. The system develops a feedback signal responsive to changes in the temperature of the steam discharged from the superheater to readjust the enthalpy of the steam entering the superheater as required to maintain the steam leaving the superheater at a predetermined set point temperature.

Abstract: A controller for close positioning or modulating control of an electric motor is disclosed. The controller compares a signal representative of the demand on the system with a signal representative of the actual position of the motor or a valve associated therewith, and if the difference between the signals exceeds a "deadband" and no action has been taken within a first time interval, and if the last movement of the valve was in the same direction and a second time interval has elapsed, a motor run pulse is generated. If the last movement of the valve was in a direction opposite to that desired, the motor run pulse is extended to overcome "backlash" resulting from the reversal of motor rotation.

Abstract: A system for controlling the bed level of a fluidized bed independent of the density of the bed material using a minimum number of pressure sensors is disclosed. A pressure sensor is positioned at the base of the bed, at approximately eight feet above the distributor plate, and at one or more intermediate locations therebetween. The measurements from the foregoing sensors are selectively processed through the use of a specific logic arrangement to produce an output signal representative of the bed level of the fluidized bed.

Abstract: A method of identifying a parameter of a model for a rate of loss of boiler efficiency due to a sootblowing operation, in a boiler or other convection heat transfer device having a plurality of heat traps, comprises measuring a time since a last sootblowing operation in the heat trap in question, measuring an overall boiler efficiency at the beginning of sootblowing for the heat trap in question, measuring a change in efficiency due to the sootblowing operation and calculating the parameter using an equation. According to the equation, the ratio of efficiency change over overall boiler efficiency equals the time factor since the last sootblowing operation times the parameter minus a summation of factors for each of the other heat traps and their associated sootblowing operations.

Abstract: A load control for a system comprised of a plurality of energy converters wherein a System Control Signal proportional to system load is developed and utilized to simultaneously adjust the rate of energy conversion of each of the converters in parallel in accordance with changes in system load. The rate of energy conversion for each converter, while operating under stead-state conditions for a predetermined period of time, is readjusted until its actual incremental cost of production is equal to a desired incremental cost.