Abstract: A cushioning structure may be provided that utilizes multiple layers of differing materials, each providing a different aspect of comfort, cooling, and support. In one aspect of the invention a first layer comprises an elastomeric gel supported in a foam structure. In another aspect an additional layer comprises a liquid gel-infused viscoelastic foam. In a further aspect, an additional layer comprises a high-density polyurethane foam. In a further aspect, an additional layer comprises a foamed latex.

Abstract: A Phase Locked Loop system (10) provides the signals UP and DOWN for a charge pump (14). The charge pump (14) supplies a biasing signal to a voltage controlled oscillator (18). The phase and frequency relationship between a feedback signal from the voltage controlled oscillator (18) and a clock signal are used by a compensating phase-frequency detector (12) to generate the signals UP and DOWN. The pulse width of the signal DOWN is limited when a transition of the clock signal is missed. An error detector (36) provides a signal BADCLK after detecting that multiple transitions of the clock signal have been missed. The signal BADCLK generates the signal UP having a pulse width that compensates for the last signal DOWN and keeps the biasing signal to the voltage controlled oscillator (18) relatively constant when the clock signal fails.

Abstract: In a combined cycle electrical power generator plant, the shut-down process includes a cooldown control period which is minimized before shutting down the gas turbine by detecting first whether a non-steaming condition has been reached and whether the gas turbine has been reduced to minimum load.

Abstract: The invention relates to a combined heat recovery steam generator and steam turbine. An adaptive temperature controller establishes a target temperature for controlling the boiler temperature so that the steam admitted on the boiler follows a constant enthalpy when trying to match temperature of steam and rotor temperature.

Abstract: In a combined cycle plant boiler an inlet temperature is adjusted or controlled while concurrently modulating the IGV's and the load of the gas turbine and the attemperator of the boiler, and concurrent modulation of the IGV's, the gas turbine load, the attemperator is effected as upon three independent control variables to adjust and/or maintain the boiler outlet temperature independently of steam turbine operation and to maximize gas turbine load control range. Control of the output temperature of one boiler is also managed in relation with the mixed temperature of steam from other boilers fluidly connected to the steam turbines.

Abstract: A coupling controller opens a dump valve at the outlet of a heat recovery steam generator when such generator is to be coupled to another generator being in operation with a steam turbine on a common header. The controller gradually permits pressure build-up until the pressure at the outlet of the new generator matches the pressure behind the header. The controller also responds to critical conditions in the superheater as well as in the high pressure drum of the generator in the operation.

Abstract: In a combined steam generator-turbine system, a drain type is provided in front of the stop valve to drain the first steam supply with the stop valve closed until the temperature of the valve and/or the temperature of the steam exceeds the temperature of saturation by a predetermined amount, and logic circuitry is provided to generate permissive signals which combine to allow successive admission of steam to the gland seal and to the steam turbine.

Abstract: In a combined cycle steam generation power plant, until steam extraction can be used to reheat the deaerator, the economizer and/or the pegging recirculation are controlled so as to track the pressure upwards of the autocirculation reheater from the low pressure evaporator with a certain lag in pressure, and to establish pressure in the deaerator on the decreasing trend of the autocirculation reheater at a slower rate and without lowering below a minimum pressure so as to prevent the occurrence of bubbling and cavitation effect.

Abstract: Boiler feedpump net positive suction head (NPSH) control is performed in a heat recovery steam generator including a deaerator inserted between steam turbine condensate and steam boiler. To this effect apparatus is provided responsive to temperature at the output of the deaerator, to fluid flow therefrom, and to temperature at the input of the boiler feedpump for providing a signal representative of the anticipated suction head pressure, and the NPSH margin is derived by comparison with actual pressure to control the pegging valve, or other heat source control to the deaerator.

Abstract: A combined cycle power plant includes a gas turbine and an afterburner to which fuel is supplied for speed and load control. Water is injected into the turbine combustors by a controlled water injection system to control total NOx emissions from the turbine and the afterburner as a function of turbine load corrected for changes in inlet air temperature and inlet guide vane position.

Abstract: A gas turbine and an afterburner are operated with a dual liquid fuel system. During protective stops, logic controls are provided for initiating a transfer from operating fuel to a flushing fuel after predetermined conditions are satisfied. After fuel transfer, shutdown is completed without setting trips and restart can be achieved without special prestart preparation of the fuel system.