A pump having an adjustable delivery volume, including: a pump housing featuring a delivery chamber which includes a delivery chamber inlet for a fluid and a delivery chamber outlet for the fluid; a delivery member, which can be rotated within the delivery chamber, for delivering the fluid; an adjusting device featuring a setting structure, which is mounted such that it can move back and forth within the pump housing in order to adjust the delivery volume of the pump, and a helical spring for applying a spring force, which acts in a setting direction, to the setting structure, wherein the windings of the helical spring are enclosed by an envelope lying on the outside of the helical spring wherein the cross-sectional area of the envelope as measured transversely with respect to the longitudinal direction of the spring changes progressively in the longitudinal direction of the spring.

A pump having an adjustable delivery volume, including: a pump housing featuring a delivery chamber which includes a delivery chamber inlet for a fluid and a delivery chamber outlet for the fluid; a delivery member, which can be rotated within the delivery chamber, for delivering the fluid; an adjusting device featuring a setting structure, which is mounted such that it can move back and forth within the pump housing in order to adjust the delivery volume of the pump, and a helical spring for applying a spring force, which acts in a setting direction, to the setting structure, wherein the windings of the helical spring are enclosed by an envelope lying on the outside of the helical spring wherein the cross-sectional area of the envelope as measured transversely with respect to the longitudinal direction of the spring changes progressively in the longitudinal direction of the spring.

A multi-channel positive displacement piston pump apparatus includes a motor and a plurality of positive displacement piston pumps driven by the motor. The plurality of pumps are aligned in a stacking direction, and each pump has an intake port and an outlet port, wherein the intake ports and the outlet ports of all pumps face in the same direction generally perpendicular to the stacking direction. In a method for retrofitting a positive displacement piston pump for use in a multi-channel pumping apparatus, an outlet port of a pump housing of the pump and a flush outlet port of the pump housing are plugged and an alternative fluid path is formed within the pump housing. The outlet port is disposed in line with an inlet port of the pump housing but on an opposite side of the pump housing. The flush outlet port is disposed in line with a flush inlet port of the pump housing but on an opposite side of the pump housing. In this way, the alternative fluid path is formed between the inlet port and the flush inlet port.

A fluid working system such as a pump for displacing a working fluid such as hydraulic fluid or a motor using a working fluid is provided. The system may have a positive displacement machine which includes one or more working chamber with displacement means such as a cylinder with a reciprocating piston. There are also two or more fluid ports to allow the working fluid to flow into and out of the working chamber. The working fluid flows from one fluid port means to another either being forced to do so when pumped or moving the piston when functioning as an engine. The fluid working system has associated therewith a non-dead compliance volume of a material such as syntactic foam. This compliance volume acts to smooth any pressure fluctuations within the working fluid system.

A fluid working system such as a pump for displacing a working fluid such as hydraulic fluid or a motor using a working fluid is provided. The system may have a positive displacement machine which includes one or more working chamber with displacement means such as a cylinder with a reciprocating piston. There are also two or more fluid ports to allow the working fluid to flow into and out of the working chamber. The working fluid flows from one fluid port means to another either being forced to do so when pumped or moving the piston when functioning as an engine. The fluid working system has associated therewith a non-dead compliance volume of a material such as syntactic foam. This compliance volume acts to smooth any pressure fluctuations within the working fluid system.

A variable displacement vane pump is described. The pump includes a control chamber provided between a housing and a control slide. A pressure-controlled relief valve is in fluid communication with the outlet path and moves to block or unblock a relief port based on output pressure of the lubricant. A feedback channel fluidly connects the control chamber to an inlet path of the pump. The feedback channel further connects to a control port that is connected to a main control valve. The relief valve and control valve are distinct and not fluidly connected. The relief valve moves once the pressure in the outlet path exceeds a predetermined amount, opening the relief port, and thus delivers a portion of the output lubricant to the control chamber via the relief port, thereby pressurizing the control chamber and reducing eccentricity of the pump by displacing the control slide.

A variable displacement vane pump is described. The pump includes a control chamber provided between a housing and a control slide. A pressure-controlled relief valve is in fluid communication with the outlet path and moves to block or unblock a relief port based on output pressure of the lubricant. A feedback channel fluidly connects the control chamber to an inlet path of the pump. The feedback channel further connects to a control port that is connected to a main control valve. The relief valve and control valve are distinct and not fluidly connected. The relief valve moves once the pressure in the outlet path exceeds a predetermined amount, opening the relief port, and thus delivers a portion of the output lubricant to the control chamber via the relief port, thereby pressurizing the control chamber and reducing eccentricity of the pump by displacing the control slide.

An electric machine (101) for use in an aircraft is shown. The electric machine comprises a casing (104) containing electromechanical components, a shaft (106) which extends outside of the casing, a seal (107) to seal the casing around the shaft, and a depressurisation system (102) configured to depressurise the casing below an external pressure to prevent electrical breakdown within gas in the casing.

An electric machine (101) for use in an aircraft is shown. The electric machine comprises a casing (104) containing electromechanical components, a shaft (106) which extends outside of the casing, a seal (107) to seal the casing around the shaft, and a depressurisation system (102) configured to depressurise the casing below an external pressure to prevent electrical breakdown within gas in the casing.

A rotary pump including: a pump housing including a delivery chamber, having an inlet and an outlet for a fluid; a delivery member which can be rotated about a rotational axis in the delivery chamber in order to deliver the fluid; a setting structure which can be moved translationally back and forth in the pump housing relative to the delivery member in and counter to a setting direction in order to adjust the delivery volume of the rotary pump; a setting device for generating a setting force which acts on the setting structure in the setting direction; a restoring spring for exerting a restoring force which acts on the setting structure counter to the setting direction; and an additional spring for exerting an additional force which acts on the setting structure in or counter to the setting direction.