SYSTEM OPERATORS running a process from a gas cylinder source sometimes may observe a puzzling phenomenon — on the downstream side of a pressure-reducing regulator the outlet pressure increases lor no apparent reason. As the cylinder drains, inlet pressure to the regulator will decrease. Simple logic suggests the outlet pressure also should decrease. However, in fact, the outlet pressure rises, leading many an operator to think the regulator is malfunctioning. This phenomenon may have a number of possible causes. The most likely one isn't a malfunctioning regulator but is the supply pressure effect (SPE), which sometimes is referred to as "dependency." It's best to minimize SPE. If a regulator's SPE is too high, the pressure change may impact the effectiveness of the system.
展开▼
