System for supplying a pressurized liquid for machines for preparing beverages comprising a first cylinder (2a) and plunger (2b) assembly (2), said plunger (2b) defining inside its cylinder (2a) a chamber (5) for housing said liquid, said plunger (2b) being able to accumulate, in an active position, potential energy from the compression force applied to a fluid, said potential energy being susceptible of being transmitted as a pressure to the liquid inside said chamber (5), and it is characterized in that it comprises a second cylinder (3a) and plunger (3b) assembly (3), said second plunger (3b) defining inside its cylinder (3a) a chamber (4) for housing said fluid, said first (2) and second (3) assemblies of plunger (2b, 3b) and cylinder (2a, 3a) being associated so that the plunger (2b) of the first assembly (2) is susceptible of accumulating, in its active position, potential energy from the compression force applied to the fluid housed inside the second assembly (3). Method for supplying pressurized liquid comprising the following steps: a) moving by continuous or discrete steps the plunger (2b) of said first assembly (2) to an active position in which said plunger (2b) accumulates potential energy from the compression force applied to the fluid housed inside the chamber (4) of the second assembly (3), b) charging liquid from a tank (14) in the chamber of the cylinder (2a) of said first assembly (2), said charging being done preferably during step a), when the plunger (2b) of the first assembly (2) is moved, the inline valve (15a) of the liquid distribution duct (11) remaining closed during said charge, and c) driving the push-button (16) associated with the liquid distribution duct (11) for opening the inline valve (15a) of said duct (11) and permitting the exit of pressurized liquid.

The invention relates to a fluid compression apparatus comprising a first and a second compression chamber, an intake system communicating with the first compression chamber, a transfer system communicating with the first and second compression chambers, and a mobile piston for ensuring the compression of the fluid in the first and second compression chambers. The apparatus further comprises a discharge port which communicates with the second compression chamber and is configured to allow the outlet of compressed fluid, wherein the second compression chamber is defined by a part of the body of the piston and a fixed wall of the apparatus, the piston being translationally mobile according to a longitudinal direction, the piston having a tubular portion mounted around a fixed central guide, a terminal end of the central guide forming the fixed wall defining a part of the second compression chamber. The apparatus further comprises a sealing system formed between the central guide and the piston according to the longitudinal direction of translation of the piston, the intake system being located at a first end of the apparatus, the discharge port being located at a second end of the apparatus and the transfer system being located between the intake system and the discharge port.

A piston pump for a traction-controlled hydraulic vehicle braking system includes a pump piston and an annular piston that is arranged as a second piston in a resiliently loaded manner on the pump piston. As the delivery pressure increases, a resilient element is compressed and a stroke of the second piston is shortened so as to reduce a delivery quantity. This configuration enables a higher delivery pressure to be achieved for a given driving force. With low delivery pressure, the pump piston and the second piston deliver together so as to achieve a rapid build-up of pressure.

A variable displacement hydraulic device comprising: a housing having an inlet for receiving hydraulic fluid and an outlet for outputting the hydraulic fluid, the housing having a reciprocation axis; a first cylinder positioned in the housing along the reciprocation axis, the first cylinder having a first input for receiving the hydraulic fluid on a first intake stroke and a first output for ejecting the hydraulic fluid on a first exhaust stroke; a first piston positioned for a first reciprocal motion within the first cylinder, the first piston having a first main end exposed to the hydraulic fluid and a second main end coupled to an actuator, the actuator for driving the second main end when coupled to the actuator for causing the first reciprocal motion to induce a first portion of said outputting of the hydraulic fluid; a second cylinder positioned in the first piston along the reciprocation axis, the second cylinder having a second input for receiving the hydraulic fluid on a second intake stroke and a second output for ejecting the hydraulic fluid on a second exhaust stroke; a second piston positioned for a second reciprocal motion within the second cylinder, the second piston having a first secondary end exposed to the hydraulic fluid and a second secondary end coupled to the actuator, the actuator for driving the second secondary end when coupled to the actuator for causing the second reciprocal motion to induce a second portion of said outputting of the hydraulic fluid; and a locking mechanism for inhibiting the first reciprocal motion of the first piston; wherein when engaged the locking mechanism inhibits the first portion of said outputting of the hydraulic fluid by decoupling the first piston from the actuator while continued operation of the actuator provides the second portion of said outputting of the hydraulic fluid by the second piston.

A reciprocating jetting water pump primarily for use on a vacuum truck is disclosed. The jetting water pump includes a pair of reciprocating pistons that are each movable within an outer cylinder mounted to a center block. Each of the outer cylinders is mounted to the center block by a plurality of tie-rod that each extend between the center block and an end plate. An airflow passageway is formed in the center block to vent air trapped within the open interior of the first outer cylinder during reciprocating movement of the piston in the first outer cylinder. A control system mounted to the vacuum truck senses the pressure of water leaving the jetting water pump and controls the supply of pressurized hydraulic fluid to the jetting water pump to maintain the water pressure at an operator selected value.

A linear compressor is provided that may include a cylinder, to which a discharge valve may be coupled; a first piston, which may be provided to enable a reciprocating motion in an inside of the cylinder; a second piston, which may be provided to enable a reciprocating motion in an inside of the first piston; a first compression chamber formed between the discharge valve and the first piston; and a second compression chamber formed between the first piston and the second piston. The first piston and second piston may move in opposite directions with respect to each other.

The invention relates to a fluid compression apparatus and method comprising first and second compression chambers, an intake system into the first chamber, a transfer system from the first chamber to the second chamber, a piston for ensuring the compression of the fluid in the first and second chambers, and an orifice for discharging the compressed fluid, the intake system comprising one or more valves, the apparatus further comprising a discharge orifice allowing communication between the first compression chamber and the bath to allow surplus liquid trapped in the first compression chamber to leave during a compression movement of the piston in the first compression chamber, the apparatus comprising a discharge valve configured to control the discharge of liquid via the discharge orifice and to prevent fluid from entering the compression chamber via the discharge orifice.

The invention relates to a fluid compression apparatus (1) comprising a sealed enclosure (13) intended to contain a bath (16) of cryogenic fluid, a first (3) and a second (4) compression chambers, an intake system (2) for admission into the first chamber (3), a system (6) for transfer from the first (3) to the second (4) chamber, the apparatus (1) further comprising a communicating discharge orifice (7) for compressed fluid to leave the second chamber, the apparatus (1) further comprising a discharge orifice provided with a valve (9) for discharge from the first compression chamber (3) to the bath (16) so as to let surplus liquid leave during compression of fluid in the first chamber (3), the discharge orifice communicating with the enclosure (13) via at least one flow retarder (10) configured to attenuate the speed and/or intensity of the discharged liquid flow by limiting its pressure drop.

A double acting two stage piston type pump includes a pump housing having a piston arrangement connected to a driving shaft which, when driven, sets the piston arrangement into movement. The piston arrangement has at least two primary stage pistons, the primary stage pistons being slidably seated in respective primary stage cylinders formed in the pump housing. The piston arrangement also includes at least two secondary stage pistons slidably seated in respective secondary stage cylinders formed in the primary stage pistons. The primary stage pistons and the secondary stage pistons are mounted on, and directly driven by, eccentrics mounted on the driving shaft.

A reciprocating piston pump includes a pump module, a drive, and an auxiliary piston. The pump module includes a cylinder head, a cylinder and a piston that form a conveying chamber. The piston converts a drive movement of the drive into conveying and suctioning stroke movements. The auxiliary piston is between the drive and the piston. The cylinder, the piston and the auxiliary piston convert the drive movement into auxiliary conveying and suctioning stroke movements, and convert the auxiliary conveying stroke movement into the conveying stroke movement of the piston via a lubricating medium in a lubricating chamber formed by the cylinder, the piston and the auxiliary piston head. A head surface of the auxiliary piston is smaller than a head surface of the piston, so that, during the auxiliary conveying stroke movement, a pressure in the lubricating chamber is greater than a pressure in the conveying chamber.