The letdownheatexchanger reduces letdown fluid temperature to a value that is compatible with the ion exchanger resin.
下泄热交换器将流体的温度降到合适的定值，这个温度下，净化床工作允许。
2
The letdown back-pressure regulating valve maintains pressure in the section of letdown upstream or the letdownheatexchanger to prevent the letdown liquid flashing to steam.
下泄背压控制阀维持下泄流上游段或下泄热交换器处的压力，防止压力过低引起流体汽化。
3
All of the ion exchanger resins are temperature sensitive; therefore, a temperature diver valve bypasses letdown flow if the letdownheatexchanger outlet temperature rises to a predetermined value.