A compressor includes: a shell forming an outer portion thereof and having lower part in which an oil pan is formed to store oil; a motor provided in the shell; a compression unit provided in the shell to compress a working gas when being driven by the motor; a frame fixed to the shell and supporting the compression unit; a shaft supported by the frame, connecting the motor and the compression unit, provided to transmit a turning force of the motor to the compression unit, and including an oil passage; and an oil pump provided at lower part of the shaft to draw oil from the pan and supply the oil into the oil passage. The pump includes a bypass valve that is opened, when a pressure of oil flowing in the oil passage is higher than a threshold pressure, to return part of the oil to the pan.

A lubricating oil supply apparatus having a structure in which a valve is forced in a direction for opening a bypass hole by a centrifugal force, and a spring presses the valve in a direction in which the valve closes the bypass hole. When the above-described structure is applied to an oil pump in which an oil (lubricating oil) supply amount increases in proportion to an operation speed, it is possible to secure a sufficient oil (lubricating oil) supply amount in a low speed operation mode, and prevent oil from being supplied more than necessary in a high speed operation mode.

An oil supply system for a compressor according to an embodiment includes an oil separator connected to a discharge pipe of the compressor, an oil tank for receiving oil from an oil sump of the oil separator, an oil pipe disposed between the oil separator and the oil tank, a pressure reducing valve disposed on the oil pipe, an oil supply pipe for supplying the oil to an oil line for supplying the oil to the compressor from an oil sump of the oil tank, and an agitator disposed on the oil pipe.

A method for monitoring an oil-injected screw compressor configured to compress aspirated air by returning oil from an oil separator vessel (11) to a compression chamber (12) of a compressor block (30), for condensate formation in the oil circuit due to a too low compression discharge temperature (VET), determines a water inlet mass flow {dot over (m)}.sub.ein(t) and a water outlet mass flow {dot over (m)}.sub.aus(t) for a point in time t and determines generated condensate flow Δ{dot over (m)}.sub.w(t)={dot over (m)}.sub.ein(t)−{dot over (m)}.sub.aus(t) on the basis of difference formation.

A portable vacuum pump with a lubricating oil system having a quick oil change system. The oil change system includes at least two containers of oil and a switch mechanism operable to initially place the first container in fluid communication with the vacuum pump to serve as the primary oil reservoir while isolating the second container from such fluid communication. Then in a snap action, the switch mechanism can be flipped to place the second container with clean oil in fluid communication with the vacuum pump to serve as the primary oil reservoir and isolate the first container from fluid communication when its oil becomes dirty, all while the vacuum pump is still operating to evacuate an AC/R system. The first container can then be removed, refilled with clean oil, and returned in place and the switch mechanism flipped back to it when the second container of oil becomes dirty.

A method for monitoring an oil-injected screw compressor configured to compress aspirated air by returning oil from an oil separator vessel (11) to a compression chamber (12) of a compressor block (30), for condensate formation in the oil circuit due to a too low compression discharge temperature (VET), determines a water inlet mass flow {acute over (m)}.sub.ein(t) and a water outlet mass flow {acute over (m)}.sub.aus (t) for a point in time t and determines generated condensate flow Δ{acute over (m)}.sub.w (t)={acute over (m)}.sub.ein(t)−{acute over (m)}.sub.aus (t) on the basis of difference formation.

An internal gear pump for forward and reverse operations, including: a pump housing which includes a first fluid port and a second fluid port, wherein in a first rotational direction, the first fluid port is formed as a fluid outlet and the second fluid port is formed as a fluid inlet, and in a second rotational direction, the first fluid port is formed as a fluid inlet and the second fluid port is formed as a fluid outlet; an internal gear and an external gear which together form delivery cells in order to deliver a fluid; a first rotary bearing which mounts the internal gear; and a second rotary bearing which mounts the external gear; and includes a lubricant feed which sets a fluid flow between the fluid ports through the two rotary bearings in both rotational directions.

A compressor includes a casing that stores lubricant at a bottom, a compression mechanism disposed in the casing to suck and compress a refrigerant, and an oil return member forming an oil return flow path that extends in a top-to-bottom direction to guide the lubricant discharged from the compression mechanism downward. The oil return flow path includes a uniform-cross-section flow path, and a varying-cross-section flow path continuous with a lower end of the uniform-cross-section flow path. A lower end of the varying-cross-section flow path forms an outlet of the oil return flow path and lies along an inner surface of the casing. A the lower end of the varying-cross-section flow path has a greater width than an upper end of the varying-cross-section flow path, and the lower end of the varying-cross-section flow path has a smaller thickness than the upper end of the varying-cross-section flow path.

The present invention provides a vertical, axial flow oil pump (10). The oil pump includes: a casing (11), the casing having a cylindrical shape as a whole and being able to rotate around its own central axis (O); a suction port (12), located at a lower end of the casing in an axial direction, and configured to suck oil into the oil pump; a discharge port (13), located at an upper end of the casing in the axial direction, and configured to discharge the oil from the oil pump to outside; and an impeller (14), provided in and formed integrally with the casing. The impeller rotates together with the casing when the casing rotates, so that the oil is flowed from the suction port to the discharge port. The present invention also provides a scroll compressor having the oil pump.

Disclosed are an oil supplying mechanism, and a horizontal compressor having same. Disclosed is an oil supply mechanism for a horizontal compressor, the horizontal compressor including a housing, a motor, a rotating shaft driven by the motor, and a bearing pedestal supporting the rotating shaft. The oil supply mechanism includes a separating member, the separating member being in the form of a ring having a central hole for allowing the bearing pedestal to pass therethrough, and the separating member being configured to separate the housing into an oil storage chamber and a motor chamber with the motor provided therein. The separating member is constructed to have an annular groove opening into the oil storage chamber. The oil supply mechanism and the horizontal compressor having the oil supply mechanism can reduce or minimize free space in the motor chamber and/or facilitate a quality inspection on the structure of a pump.