Variable throttle device

Abstract

A variable throttle device comprises at least two fixed throttle orifices and one switch device. The at least two fixed throttle orifices are connected in series; and the switch device is connected in parallel with at least one of the at least two fixed throttle orifices. In another implementation, a variable throttle device comprises at least two throttle passages and one switch device, each of the at least two throttle passages has at least one fixed throttle orifice or a plurality of fixed throttle orifices connected in series, the at least two throttle passages are connected in parallel, and the switch device is connected in series with at least one of the at least two throttle passages to selectively open or close the at least one throttle passage. The variable throttle device can increase or decrease the throttling resistance to meet the requirements of the valve seating velocity under different operating conditions.

Dependencies are inferred from the claim text.