A pressure relief passage includes a first pressure relief passage and a second pressure relief passage. A pressure relief hole is provided in an upper part of the first pressure relief passage in the direction of gravitational force. The second pressure relief passage merges with the first pressure relief passage to form a merging portion. The cross-sectional flow area of a stagnation portion, which is the maximum cross-sectional flow area of the second pressure relief passage, is smaller than the cross-sectional flow area of a connection passage, which is the minimum cross-sectional flow area of the first pressure relief passage.

First and second pressure relief passages extend from an oil pan in a branching manner, and merge with each other to form a merging portion. A pressure relief hole is arranged above the merging portion, and a first pressure relief passage is arranged below the merging portion. The minimum cross-sectional area of the second pressure relief passage is smaller than the minimum cross-sectional area of the first pressure relief passage. The second pressure relief passage includes a bent portion formed by bending the second pressure relief passage. The bent portion is configured to perform gas/liquid separation by crushing bubbles. When reaching the merging portion from the bent portion, oil is returned to the oil pan via the first pressure relief passage. When reaching the merging portion from the bent portion, gas is discharged to the outside of the housing via the pressure relief hole.

A vaneless contra-rotating compressor with multiple contra-rotating interfaces and application of the vaneless contra-rotating compressor is provided, which includes at least two vaneless contra-rotating interfaces. For each of the at least two contra-rotating interfaces, the contra-rotating interface corresponds to two of vaneless contra-rotating rotors. A rotating direction of an upstream rotor of the two vaneless contra-rotating rotors and a rotating direction of a downstream rotor of the two vaneless contra-rotating rotors are opposite. Rectifier stator vanes are not provided among all the rotors to supply sufficient inlet negative pre-swirl for the downstream rotors through the upstream rotors. Only the outlet guide vanes of the last stage, of the vaneless contra-rotating rotors are provided. The number of stages and the number of vaneless contra-rotating interfaces may be set flexibly according to the actual pressurization requirements.

The present invention is directed to a load bearing direct-drive system and a variable process control system for efficiently managing the operation of fans in a cooling system such as a wet-cooling tower, air-cooled heat exchanger (ACHE), HVAC system, blowers and centrifugal blowers, mechanical towers or chiller systems. In one embodiment, the load bearing direct-drive system comprises a load bearing torque multiplier device having an output rotatable shaft connected to a fan, and a load bearing motor comprising a rotatable shaft that drives the load bearing torque multiplier device.

A compressor system includes a driving unit having a drive shaft, a plurality of compressors which compress a gas, and a transmission mechanism which increases a speed of a rotation of the drive shaft and transmits the rotation to the plurality of compressors. The transmission mechanism includes a main shaft which rotates together with the drive shaft and a plurality of gear mechanisms which transmit a rotation of the main shaft to the corresponding one compressor. The gear mechanism includes an auxiliary shaft which rotates together with an auxiliary gear meshing with the main gear, a plurality of first gears which rotate together with the auxiliary shaft, an output shaft to which an output gear meshing with the first gear is fixed and which is connected to the compressor, and a first bearing which rotatably supports the auxiliary shaft, and a second bearing which rotatably supports the output shaft.

A transmission includes a transmission housing member, a ring portion, a high speed shaft, a third roller, and a third plate bearing, which rotatably supports the third roller. The transmission housing member includes a first supporting surface, which restricts the third roller to a first position, and a second supporting surface, which restricts the third roller to a second position. The third roller is moved within a movement range from the first position to the second position. The movement range includes a specified range in which the third roller is not supported, in a radial direction of the high speed shaft, by the transmission housing member with the third plate bearing in between, but is supported by being held between the ring portion and the high speed shaft.

A rotary machine includes a plurality of shafts that extend in an axial direction, in which an axis extends, around the axis, are disposed such that at least parts of positions in the axial direction of the plurality of shafts overlap each other, and are rotatable relative to each other around the axis; a plurality of seal members that are disposed at intervals in the axial direction to seal gaps between the plurality of shafts in a radial direction with respect to the axis; and a seal gas supply unit configured to supply a seal gas from outside to a space surrounded by the plurality of shafts and the plurality of seal members.

First and second pressure relief passages extend from an oil pan in a branching manner, and merge with each other to form a merging portion. A pressure relief hole is arranged above the merging portion, and a first pressure relief passage is arranged below the merging portion. The minimum cross-sectional area of the second pressure relief passage is smaller than the minimum cross-sectional area of the first pressure relief passage. The second pressure relief passage includes a bent portion formed by bending the second pressure relief passage. The bent portion is configured to perform gas/liquid separation by crushing bubbles. When reaching the merging portion from the bent portion, oil is returned to the oil pan via the first pressure relief passage. When reaching the merging portion from the bent portion, gas is discharged to the outside of the housing via the pressure relief hole.

An oil passage of a centrifugal compressor includes a first oil passage that communicates with an oil pan and a speed increaser chamber to supply oil to a speed increaser and the seal. A second oil passage communicates with the speed increaser chamber. A third oil passage extends upward in a gravitational direction from an end of the second oil passage. A fourth oil passage extends in a horizontal direction and causes the oil pan and an end of the third oil passage to communicate with each other. A pressure relief passage that communicates with an outside is arranged in at least one of a portion of the fourth oil passage through which a gas layer passes and a portion of the oil pan in which the gas layer is stored.

A fan wheel with a hub is centrally supported with respect to a drive and coaxially rotatable with the hub between stops relative to the hub. The fan wheel having fan blades extending radially from the hub are rotatable about their axes in a range delimited by the stops. Overlaying the rotational support between the stops of the hub, a rotational support between the hub and the drive is provided including a planetary drive in operative arrangement with an adjustment control ring of the driven hub. The fan blades are rotatable in the hub about their blade axes, and adjustment of the blade angles of the fan blades via drive connections to the adjustment control ring, which connections operate in a manner superimposed on one another starting from the drive of the fan wheel.