A four-stroke internal combustion engine comprising an inlet cam configured to open and close an inlet valve, a No. 1 exhaust cam configured to open and close an exhaust valve, a No. 2 exhaust cam configured to open and close the same exhaust valve, wherein the No. 2 exhaust cam is angularly adjustable relative to the No. 1 exhaust cam in response to input from an operator, so that the No. 2 exhaust cam is able to be selectively engaged; wherein the No. 1 exhaust cam is configured to open and close the exhaust valve during the compression stroke, so that a selected quantity of air drawn in during the intake stroke is expelled during the compression stroke; and wherein the No. 2 exhaust cam is configured to optionally close the exhaust valve when engaged.

A closed cycle plant for converting thermal power to mechanical or electrical power including: a closed circuit inside which a working fluid circulates according to a predetermined circulation direction, a volumetric expander configured to receive at the inlet the working fluid in a gaseous state. The volumetric expander includes: a jacket having an inlet and an outlet for enabling the introduction and discharge the working fluid; an active element housed in said jacket and suitable for defining, in cooperation with said jacket, a variable volume expansion chamber; a main shaft; a valve active that opens and closes the inlet and outlet, and a generator connected to the main shaft. The valve includes a regulation device configured to vary the duration of the introduction condition, or the maximum through cross-section of the inlet.

A four-stroke internal combustion engine comprising an inlet cam configured to open and close an inlet valve, a No. 1 exhaust cam configured to open and close an exhaust valve, a No. 2 exhaust cam configured to open and close the same exhaust valve, wherein the No. 2 exhaust cam is angularly adjustable relative to the No. 1 exhaust cam in response to input from an operator, so that the No. 2 exhaust cam is able to be selectively engaged; wherein the No. 1 exhaust cam is configured to open and close the exhaust valve during the compression stroke, so that a selected quantity of air drawn in during the intake stroke is expelled during the compression stroke; and wherein the No. 2 exhaust cam is configured to optionally close the exhaust valve when engaged.

An energy recovery system in a seawater desalination plant uses a reverse-osmosis membrane method for removing salinity from seawater. The system is configured to supply high-pressure water produced by pressurizing raw water with a high-pressure pump to a reverse-osmosis membrane cartridge, and to supply concentrated water discharged from the cartridge to an isobaric energy recovery device to recover pressure energy of the concentrated water whereby part of the raw water supplied to the isobaric energy recovery device is pressurized, and then to allow the pressurized raw water to merge into the high-pressure water pressurized by the high-pressure pump. The system includes a booster pump for boosting a pressure of the concentrated water discharged from the cartridge, and an energy recovery turbine for recovering energy by using the pressure head difference between the pressurized raw water from the isobaric energy recovery device and the high-pressure water discharged from the pump.

An energy recovery system in a seawater desalination plant uses a reverse-osmosis membrane method for removing salinity from seawater. The system is configured to supply high-pressure water produced by pressurizing raw water with a high-pressure pump to a reverse-osmosis membrane cartridge, and to supply concentrated water discharged from the cartridge to an isobaric energy recovery device to recover pressure energy of the concentrated water whereby part of the raw water supplied to the isobaric energy recovery device is pressurized, and then to allow the pressurized raw water to merge into the high-pressure water pressurized by the high-pressure pump. The system includes a booster pump for boosting a pressure of the concentrated water discharged from the cartridge, and an energy recovery turbine for recovering energy by using the pressure head difference between the pressurized raw water from the isobaric energy recovery device and the high-pressure water discharged from the pump.

A pulse-width-regulating valve is for the regulation of a fluid flow or a fluid pressure. The pulse-width-regulating valve comprises a cut-off valve connected in series with an inflow valve, at least one of the cut-off valve and the inflow valve being provided with an axially displaceable or rotatable valve element which has an opening position or a closing position at a distance from a starting position of the valve element. A method of operating a pulse-width-regulating valve comprises: regulating a valve gear device by a valve synchronizer, in accordance with at least two displacement curves; and by one or more valve actuators, displacing or rotating corresponding valve elements arranged in the pulse-width-regulating valve.

A pulse-width-regulating valve is for the regulation of a fluid flow or a fluid pressure. The pulse-width-regulating valve comprises a cut-off valve connected in series with an inflow valve, at least one of the cut-off valve and the inflow valve being provided with an axially displaceable or rotatable valve element which has an opening position or a closing position at a distance from a starting position of the valve element. A method of operating a pulse-width-regulating valve comprises: regulating a valve gear device by a valve synchronizer, in accordance with at least two displacement curves; and by one or more valve actuators, displacing or rotating corresponding valve elements arranged in the pulse-width-regulating valve.

An energy recovery system in a seawater desalination plant uses a reverse-osmosis membrane method for removing salinity from seawater. The system is configured to supply high-pressure water produced by pressurizing raw water with a high-pressure pump to a reverse-osmosis membrane cartridge, and to supply concentrated water discharged from the cartridge to an isobaric energy recovery device to recover pressure energy of the concentrated water whereby part of the raw water supplied to the isobaric energy recovery device is pressurized, and then to allow the pressurized raw water to merge into the high-pressure water pressurized by the high-pressure pump. The system includes a booster pump for boosting a pressure of the concentrated water discharged from the cartridge, and an energy recovery turbine for recovering energy by using the pressure head difference between the pressurized raw water from the isobaric energy recovery device and the high-pressure water discharged from the pump.