What is a typical application of a back pressure or surplussing valve?

The application of a back pressure or surplussing valve is primarily associated with managing the pressure within a system to ensure efficiency and safety. In the context of flash steam recovery and flash tank pressure control, these valves play a crucial role by allowing excess steam or pressure to escape, thereby maintaining the desired pressure levels in various components of a steam system.

When utilizing flash steam recovery, the temperature and pressure of the steam can significantly impact the efficiency of the system. A back pressure valve helps in controlling the pressure within the flash tank, allowing for optimal steam recovery. By regulating the pressure effectively, it ensures that the recovered steam can be redirected or utilized without causing overwhelming pressure that could lead to system failures.

In contrast, mixing two steam sources typically does not require the precise pressure control associated with a back pressure valve. Regulating gas pressure is generally handled by different types of valves specifically designed for gas applications. Maintaining a constant flow of water involves different mechanisms and controls rather than back pressure management. Thus, the role of a back pressure or surplussing valve is most aptly demonstrated in the context of flash steam recovery and pressure control within steam systems.