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Start-up attemperator

  • US 4,208,882 A
  • Filed: 12/15/1977
  • Issued: 06/24/1980
  • Est. Priority Date: 12/15/1977
  • Status: Expired due to Term
First Claim
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1. A control system for regulating steam temperature in a desuperheating station upstream from a prime mover wherein said desuperheating station includes an attemperator device, valve means for regulating coolant flow to the attemperator and valve positioning means;

  • said control system comprising;

    redundant temperature sensing means providing first and second temperature signals into a preset difference comparator;

    alarm means connected to the output of said preset difference comparator to indicate signal invalidity whenever the first and second temperature signals differ by a preset signal difference;

    select largest logic connected to said first and second temperature signals to provide a feedback temperature signal indicative of the highest steam temperature downstream from said attemperator;

    reference signal generating means including fixed setpoint logic having a status input from said prime mover indicating at least a cold or warm condition and ramp setpoint logic including a rate increase circuit whereby control is extended beyond said fixed setpoint logic and a reference temperature signal is generated; and

    ,a valve control module including a summing junction for determining the difference between said feedback temperature signal and said reference temperature signal;

    the output of said valve control being a valve positioning signal input to said valve positioning means.

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