Abstract: A measurement of the pressure of hydraulic fluid in a fluid working machine can be determined from the timing of the movement of valves which selectively seal a working chamber of cyclically varying volume from a fluid gallery. The timing of opening of a low pressure valve, to connect a working chamber to a low pressure fluid gallery, following the closure of a high pressure valve to seal a working chamber can be used to estimate the pressure in the high pressure fluid gallery at the moment of closure of the high pressure valve.

Abstract: A valve unit for a fluid working machine comprise a valve having a valve member (and optionally a valve seat), a valve actuator coupled to the valve member, and an electronic actuator controller which is integral to the valve unit and configured to actively control the valve actuator to thereby control the valve member.

Abstract: A measurement of the pressure of hydraulic fluid in a fluid working machine can be determined from the timing of the movement of valves which selectively seal a working chamber of cyclically varying volume from a fluid gallery. The timing of opening of a low pressure valve, to connect a working chamber to a low pressure fluid gallery, following the closure of a high pressure valve to seal a working chamber can be used to estimate the pressure in the high pressure fluid gallery at the moment of closure of the high pressure valve.

Abstract: A method of detecting an object is disclosed, comprising generating a transmission signal by generating a carrier signal and digitally modulating the carrier signal with a transmission modulation signal, and transmitting the transmission signal. A reflected signal is received, the reflected signal having been reflected from the object, and demodulated to extract a received modulation signal. The received modulation signal is correlated with the transmission modulation signal and a range of the object is determined from the correlation of the received modulation signal and the transmission modulation signal.

Abstract: A valve unit for a fluid working machine comprise a valve having a valve member (and optionally a valve seat), a valve actuator coupled to the valve member, and an electronic actuator controller which is integral to the valve unit and configured to actively control the valve actuator to thereby control the valve member.

Abstract: The device to water Christmas tree according to the present invention includes an elongated transparent water bottle connected by a flexible transparent hose to an elongated tubular water feed conduit. The bottle has a hanger element on a bottom end and a closure cap having a tubular nipple on the top end. One end of the hose is connected to the cap nipple and the other end connected to a tubular nipple on the closed upper end of the tubular water feed conduit. The lower end of the tubular water feed conduit is cut at an angle forming a lower opening providing fluid communication between water in the water feed conduit and water in the reservoir of a Christmas tree stand. Securing elements are provided for securing the device to the branches and trunk of a Christmas tree.