| 摘要 |
A cascade type trim for integration into control valve and having a valve stem and a valve cage which cooperate with each other to define a plurality of fluid passageway columns, each of which extend between a valve inlet and a valve outlet. Each fluid passageway column is collectively defined by a plurality of stem passageways and a plurality of cage passageways. The stem and cage passageways are brought in and out of alignment as a result of axial movement of the stem relative to the cage. In a first position, a first fluid passageway is open, while a second fluid passageway remains closed. In a second position, both the first and second fluid passageways are open, and yet in a third position, the first fluid passageway is closed and the second fluid passageway is open. |
