High-flow rate miniature digital valve system
Keywords:fast switching, on/ off valve, solenoid actuator, hydraulic valve, Digital hydraulics
Digital hydraulic valve systems can offer several benefits compared to spool-type proportional valves, such as faster response, more flow capacity, better fault tolerance and individual metering. However, the digital valve systems currently available are large, heavy and slow and therefore there is a need to miniaturise them and simultaneously make them faster. This article describes the design and performance of a digital valve system which can be used to replace a proportional valve with ISO 03 (NFPA D03, CETOP 3, NG6) standard interface. The valve system consists of 32 pilot operated miniature on/off valves which form four independently controlled metering edges. The valve system has small dimensions (176 × 49 × 72 mm) even though it contains integrated control electronics, its response time is approximately 2 ms and flow capacity per metering edge is 30 l/min at Δp = 0.5 MPa. These properties are good, however, improvements are required to reduce the leakage caused by the pilot valves, which can reach 5 l/min per metering edge at 10 MPa pressure difference.
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