Aspects of the present invention relate to a vacuum system. The vacuum system includes a vacuum pump; and a heat exchanger for receiving a heat transfer fluid. The heat transfer fluid comprising a gas. The heat exchanger is thermally coupled to the vacuum pump and is operable to absorb thermal energy from the vacuum pump. Aspects of the present invention also relate to a method of operating a vacuum system; and a controller for controlling operation of a vacuum system.

The invention relates to a method of venting a synthetically commutated hydraulic pump (2). The connecting fluid conduits (8, 16), connecting said synthetically commutated hydraulic pump (2) with a fluid reservoir (7) is vented at least on start-up of the synthetically commutated hydraulic pump (2), using a fluid intake device (14, 17, 20) that connects to a fixed displacement pump (3).

A fuel pump includes a pump housing with a pumping chamber an inlet valve bore. An inlet valve selectively provides and prevents fluid communication between an inlet of the fuel pump and the pumping chamber. The inlet valve includes an inner housing received within the inlet valve bore such that an outer periphery of the inner housing is sealed to an inner periphery of the inlet valve bore. An outer housing circumferentially surrounds the inner housing. An annular chamber is defined radially between the inner housing and the outer housing and axially between the outer housing and the pump housing. A sealing ring is located within the annular chamber such that the sealing ring is compressed axially against the pump housing and the outer housing.

A fuel pump includes a pump housing with a pumping chamber an inlet valve bore. An inlet valve selectively provides and prevents fluid communication between an inlet of the fuel pump and the pumping chamber. The inlet valve includes an inner housing received within the inlet valve bore such that an outer periphery of the inner housing is sealed to an inner periphery of the inlet valve bore. An outer housing circumferentially surrounds the inner housing. An annular chamber is defined radially between the inner housing and the outer housing and axially between the outer housing and the pump housing. A sealing ring is located within the annular chamber such that the sealing ring is compressed axially against the pump housing and the outer housing.

Pump, in particular a high-pressure fuel pump, having at least one pump element (10) which has a pump piston (12) which is driven in a reciprocating movement by way of a drive shaft (14) with at least one cam (16; 160) and delimits a pump working chamber (24) which can be filled with delivery medium via an inlet valve (26) during the suction stroke of the pump piston (12). The at least one cam (60; 160) of the drive shaft (14) is a multiple cam with a plurality of cam delivery regions (16a, 16b) for the delivery strokes of the pump piston (12), or a plurality of single or multiple cams (160) with in each case at least one cam delivery region (160a, 160b) for the delivery strokes of the pump piston (12) are provided which are arranged next to one another in the direction of the rotational axis (15) of the drive shaft (14). The cam profiles of the cam delivery regions (16a, 16b) of the at least one multiple cam (16) or the cam profiles of the cam delivery regions (160a, 160b) of the single cams (160) are of different configuration.

An object of the present invention is to obtain a high pressure fuel supply pump capable of reducing pressure pulsation that occurs in a low pressure pipe, preventing damage to the low pressure pipe, or reducing noise due to vibrations of the low pressure pipe. The present invention provides a high pressure fuel supply pump of a type in which, from a fuel suction port connected to a low pressure pipe provided upstream of a fuel, a low pressure passage, an electromagnetic suction valve driven by an electromagnetic force, a pressurizing chamber in which the volume thereof is increased or reduced by a plunger that is reciprocatingly moved by being guided by a cylinder, and a discharge valve provided at an outlet of the pressurizing chamber are sequentially arranged, a fuel is sucked to the pressurizing chamber through the electromagnetic suction valve, the amount of a part of the fuel, which is sucked to the pressurizing chamber, to be returned to the low pressure passage side is adjusted so that the amount of the fuel to be discharged through the discharge valve is controlled, and the high pressure fuel supply pump includes a backflow suppression mechanism for suppressing backflow of fuel from the fuel from the fuel suction portion to the low pressure pipe side.

A fluid-working machine has a plurality of working chambers, e.g., cylinders, of cyclically changing volume, a high-pressure fluid manifold and a low-pressure fluid manifold, at least one valve linking each working chamber to each manifold, and electronic sequencing means for operating said valves in timed relationship with the changing volume of each chamber, wherein the electronic sequencing means is arranged to operate the valves of each chamber in one of an idling mode, a partial mode in which only part of the usable volume of the chamber is used, and a full mode in which all of the usable volume of the chamber is used, and the electronic sequencing means is arranged to select the mode of each chamber on successive cycles so as to infinitely vary the time averaged effective flow rate of fluid through the machine.

In an electromagnetically controlled inlet valve actuator provided to a high pressure fuel pump, an impinging sound which is generated at the time of operating the mechanism is reduced. In a high pressure fuel pump provided with an electromagnetically controlled inlet valve (operated by way of a plunger rod), a current supply period includes a 1st current supply period for performing an operation of attracting the plunger rod in a valve closing direction, a 2nd current supply period for alleviating a speed at which the plunger rod moves in a valve opening direction, and a limited current supply period disposed between the 1st current supply period and the 2nd current supply period in the form of spanning a pump top dead center.

Disclosed is a governor device for controlling a compressor in a pressurized air system. The governor device includes a supply port, a control port, an exhaust opening, an inlet valve between the supply port and the control port, and an outlet valve between the control port and the exhaust opening. The governor device also includes a displaceable piston and is switchable between a basic position with an open outlet valve and closed inlet valve and an actuated position with a closed outlet valve and open inlet valve. A valve arrangement is included at the piston, the valve arrangement comprising a fixed means fixed to the piston and a valve plate displaceable with respect to the fixed means.

An improved inlet valve system for a cylinder chamber of a reciprocating compressor and a method for utilizing a high pressure gas source to control an inlet valve system for a cylinder chamber of a reciprocating compressor is disclosed. The inlet valve system may include an unloader, a valve assembly including a cylindrical valve body circumferentially disposed about a central axis of the inlet valve system, and a control valve actuator including a control valve body. The valve assembly may include a plurality of inlet valve elements disposed respectively in valve element ports fluidly connected to a control valve passage. A high pressure gas source is utilized to hold open and close the inlet valve elements via the control valve passage in order to control the capacity of the reciprocating compressor.