The letdown back-pressure regulating valve maintains pressure in the section of letdown upstream or the letdown heat exchanger 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。
2
All of the ion exchanger resins are temperature sensitive; therefore, a temperature diver valve bypasses letdown flow if the letdown heat exchanger outlet temperature rises to a predetermined value.