A compressor may include a shell, first and second scrolls, a seal assembly, a modulation control chamber, and a modulation control valve. The first scroll may include a first end plate having a biasing passage extending therethrough. The seal assembly may isolate a discharge pressure region from a suction pressure region. The seal assembly and the first scroll may define an axial biasing chamber therebetween that communicates with the axial biasing chamber and a first pocket between the first and second scrolls. The modulation control chamber may be fluidly coupled with the biasing chamber by a first passage. The modulation control valve may be fluidly coupled with the modulation control chamber by a second passage and movable between a first position allowing communication between the second passage and the suction pressure region and a second position restricting communication between the second passage and the suction pressure region.

A compressor may include a shell, first and second scrolls, a seal assembly, a modulation control chamber, and a modulation control valve. The first scroll may include a first end plate having a biasing passage extending therethrough. The seal assembly may isolate a discharge pressure region from a suction pressure region. The seal assembly and the first scroll may define an axial biasing chamber therebetween that communicates with the axial biasing chamber and a first pocket between the first and second scrolls. The modulation control chamber may be fluidly coupled with the biasing chamber by a first passage. The modulation control valve may be fluidly coupled with the modulation control chamber by a second passage and movable between a first position allowing communication between the second passage and the suction pressure region and a second position restricting communication between the second passage and the suction pressure region.

A scroll compressor includes a casing accommodating a rotary shaft and a driving unit, a first scroll making an orbiting movement by the rotary shaft, a second scroll engaged with the first scroll to form a compression chamber and having a bypass hole bypassing a refrigerant sucked into the compression chamber to an internal space of the casing, and a back-pressure chamber assembly pressing the second scroll toward the first scroll, wherein the back-pressure chamber assembly includes: a back-pressure space, a first valve unit allowing the bypass hole and the internal space of the casing to selectively communicate with each other, and a second valve unit opened and closed to selectively supply the refrigerant of the back-pressure space to the first valve unit to operate the first valve unit, and positioned to be fixed to the casing.

A compressor may include a shell assembly, first and second scrolls, a piston, and a piston-retention member. The piston engages the first scroll and may be partially received within a recess defined by the shell assembly. The piston and the shell assembly may cooperate to define a pressure chamber. The pressure chamber may be in selective fluid communication with a source of working fluid to control movement of the piston relative to the shell assembly. The piston-retention member may engage the piston and a rotationally fixed structure. The piston-retention member allows rotation of the piston relative to the first scroll in a first rotational direction and restricts rotation of the piston relative to the first scroll in a second rotational direction.

Disclosed is a liquid-ring compressor including a bypass pipe, in which the bypass pipe is directly mounted to a main body of the liquid-ring compressor, thereby greatly reducing costs incurred in the installation of a facility or a system including the liquid-ring compressor, and also economically reducing maintenance costs. The liquid-ring compressor includes a main body accommodating a shaft centrally mounted therein to receive rotational force from a driving motor, a rotor configured to rotate together with the shaft inside the main body, a suction port formed at a portion of the main body, a discharge port formed at another portion of the main body, a bypass pipe mounted between a position adjacent to the suction port in the main body and a position adjacent to the discharge port in the main body, and an opening/closing valve mounted in the middle of the bypass pipe.

A scroll compressor including a bypass passage to guide refrigerant from a compression chamber to a low pressure portion of the compressor; a valve located in a valve receiving portion and slideable between first and second positions in which the bypass passage is respectively closed and opened; a ring-shaped seal between an outer peripheral surface of the valve and an inner peripheral surface of the valve receiving portion; and a seal groove formed in at least one of the outer peripheral surface of the valve and the inner peripheral surface of the valve receiving portion, the seal being inserted into the seal groove, wherein at least one of the outer peripheral surface of the valve, the inner peripheral surface of the valve receiving portion, and the inner peripheral surface of the seal groove has an inclined surface that is inclined in the opening/closing direction of the valve.

Disclosed is a liquid-ring compressor including a bypass pipe, in which the bypass pipe is directly mounted to a main body of the liquid-ring compressor, thereby greatly reducing costs incurred in the installation of a facility or a system including the liquid-ring compressor, and also economically reducing maintenance costs. The liquid-ring compressor includes a main body accommodating a shaft centrally mounted therein to receive rotational force from a driving motor, a rotor configured to rotate together with the shaft inside the main body, a suction port formed at a portion of the main body, a discharge port formed at another portion of the main body, a bypass pipe mounted between a position adjacent to the suction port in the main body and a position adjacent to the discharge port in the main body, and an opening/closing valve mounted in the middle of the bypass pipe.

A two-stage oil-injected screw air compressor includes an integrated compression casing, and the integrated compression casing further includes a first stage compression chamber, an intermediate cooling channel, and a second stage compression chamber parallel stacked in the integrated compression casing. A straightforward oil injector aims at the intermediate cooling channel to spray lubricating oil into the intermediate cooling channel.

A high-pressure pump is configured to pressurize fuel. The high-pressure pump includes a relief valve device that is placed in a relief passage, which has one end part connected to a discharge passage in a housing while another end part of the relief passage is configured to be communicated with a suction passage in the housing. The discharge passage is configured to conduct the fuel, which is pressurized in and discharged from a pressurizing chamber. The relief valve device is configured to enable or limit a flow of the fuel between one side of the relief passage, at which the discharge passage is located, and another side of the relief passage, which is opposite to the discharge passage, at a valve opening time or a valve closing time of the relief valve device.

A compressor includes a housing, a partition, a first scroll, a second scroll, and a thermal protection system. The partition is disposed within the housing and defines a suction chamber and a discharge chamber. The partition includes a discharge passage in fluid communication with the discharge chamber. The thermal protection system includes a positioning body and a displacement member. The positioning body is coupled to the second scroll and translatably disposed within the discharge passage. The displacement member is disposed between the positioning body and the partition and configured to translate the second scroll relative to the first scroll between first and second positions.