| 摘要 |
A digitally controlled valve system is composed of the main fluid control valve with a displaceable flow control portion (spool) that is controllably displaced by a digital pressure generator that generates digitally incremented pressure changes which operate against a biassing pressure or spring to displace the spool in a direct relationship to the pressure provided by the pressure generator. In one version, a main valve directs flow to either a high or a low pressure-control valve each of which is biassed toward a closed position by a pressure substantially equivalent to the pressure drop of flow of fluid through the main valve which pressure closes the valve stop flow when the pressure drop is too high (i.e. flow through the main valve is throttled). The flows through the valves are selectively adjusted via the digitally-generated pressure from the digital pressure generator. In another version of the invention the two pressure control valves are replaced by a two direction control valve that directs flow to or from the main valve which is connected to an output line. The flow rate is dependent on the spool displacement of the main valve. The position of the spool of the two direction control valve in the later version is adjusted based on the pressure drop across the main valve. Properly sizing of the flow passage orifices (and biassing pressure i.e. springs) in the main valve provides a valve system where the flow varies directly with the amount of pressure applied to displace the spool of the main valve. |
