초록 ▼

Boiler outlet temperature in a sliding pressure operation is controlled in a routine way by varying the fluid or heat distribution in the boiler. The effect a change in pressure has on steam temperature is anticipated by supplying a feedforward signal to the temperature control system from drum pres

Boiler outlet temperature in a sliding pressure operation is controlled in a routine way by varying the fluid or heat distribution in the boiler. The effect a change in pressure has on steam temperature is anticipated by supplying a feedforward signal to the temperature control system from drum pressure so as to minimize temperature variations at the boiler outlet.

대표청구항 ▼

In a drum type boiler having a superheater and a control system for modifying the operation of said boiler to control the temperature of the steam at the outlet of said superheater wherein the control system includes a controller responsive to the difference between said outlet temperature and its s

In a drum type boiler having a superheater and a control system for modifying the operation of said boiler to control the temperature of the steam at the outlet of said superheater wherein the control system includes a controller responsive to the difference between said outlet temperature and its set point for controlling the outlet temperature, the improvement which comprises: means for producing a feedforward signal proportional to the drum pressure in the boiler; and means for applying said feedforward signal to said controller in such sense as to modify the control so as to tend to minimize changes in the temperature at said outlet due solely to drum pressure changes. A method for controlling the temperature of the steam at the outlet of the superheater of a drum type boiler operating in the sliding pressure mode, comprising the steps of: automatically controlling the fluid distribution or the heat distribution in the boiler in response to the deviation of outlet temperature from its set point so as to tend to maintain said outlet temperature at its set point; and modifying said control in response to the magnitude of a feedforward signal proportional to the pressure of the steam in said drum, said modification being in sense to tend to reduce the temperature change expected solely as a result of changes in drum pressure.