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.

A fluid machine includes a bladed wheel, a resolver, a first fastener, and a second fastener. A resolver rotor is held between the first fastener and the rotary shaft and fixed to a large-diameter portion of the rotary shaft. The bladed wheel is held between the second fastener and the rotary shaft and fixed to a small-diameter portion of the rotary shaft. While the resolver rotor is fixed by the first fastener in a same direction as the bladed wheel is fixed by the second fastener along an axial direction of the rotary shaft, and the resolver rotor is fixed by the first fastener at a position away in a radial direction of the rotary shaft from a position where the bladed wheel is fixed by the second fastener so that the resolver rotor does not receive an axial force from the second fastener.

A fluid machine includes a projection, projecting from one surface toward the other surface, is provided in at least one gap among a gap between an outer peripheral surface of a rotary shaft and an inner peripheral surface of a through hole, a gap between a rear surface of a first impeller and a first facing surface of a partition wall, and a gap between a rear surface of a second impeller and a second facing surface of the partition wall. The projection cooperates with the other surface to form therebetween a clearance smaller than a first tip clearance between the first impeller and a first shroud surface of a housing and a second tip clearance between the second impeller and a second shroud surface of the housing. The projection has a collision surface that collides with the other surface when the first impeller and the second impeller vibrate.

A sealing device includes a sealing main body surrounding a rotor shaft rotating about an axis from an outer periphery side. The sealing main body includes an inside surface facing an outside surface of the rotor shaft with clearance and a plurality of hole parts formed recessed to an outer side in a radial direction from the inside surface and arrayed in a circumferential direction of the inside surface and in a direction of the axis. The hole parts have an inner peripheral wall in which a spiral groove extending twisting toward the outer side in a radial direction is formed.

A compressor includes a rotor including a plurality of disks, a shaft portion connected on a downstream side of the disks; and rotor blade rows fixed to the plurality of disks; a stator including a compressor casing; and a plurality of stator vane rows each provided between corresponding adjacent ones of the rotor blade rows; an outlet guide vane including blade main bodies disposed at an interval in a circumferential direction on the downstream side of the disk located most downstream, and inner shrouds connecting the blade main bodies in the circumferential direction, on an inner side in a radial direction; and an inner casing disposed on the downstream side of the disk located most downstream with a gap between the disk and the inner casing. The inner casing includes an outer peripheral wall surface having recesses accommodating the inner shrouds and forming, together with an inside surface of the compressor casing, a diffuser on the downstream side of the recesses, and an inner peripheral wall surface forming an air extraction cavity. An air extraction hole is formed in a portion, in the recesses, on the downstream side.

In some aspects, the techniques described herein relate to a refrigerant compressor, including: a stator; a rotor configured to rotate with respect to the stator; and at least one step seal between the rotor and the stator, wherein the step seal includes a first tooth and a second tooth extending from the rotor toward the stator, wherein a downstream surface of the first tooth and an upstream surface of the second tooth are arranged at an angle relative to one another, wherein the angle is less than 90°.

A centrifugal compressor includes a high-speed shaft, an impeller, a housing having a partition wall and a discharge passage, and a sealing member. The centrifugal compressor includes a bypass that is formed in the partition wall and has an inlet connected to the discharge passage and an outlet connected to a space between a back surface of the impeller and the partition wall. The inlet is located outward of the outlet and the outlet is located outward of the sealing member in a radial direction of the high-speed shaft. The bypass includes an outlet passage that extends to the outlet outwardly in the radial direction of the high-speed shaft. Air introduced from the inlet flows out of the outlet through the outlet passage so as to form a flow of air flowing away from the sealing member in the space.

Provided is a boil-off gas compressor for LNG-fueled vessels using LNG as fuel for a propulsion engine thereof. The boil-off gas compressor includes: compressor housings in which impellers are rotatably arranged; a motor housing in which a motor is disposed to drive the impellers; and a bearing for rotatably supporting rotation shafts, which transfer rotation drive force of the motor to the impellers. The compressor housings may be integrally formed with the motor housing.

Compressor rotor structure for turbomachinery, such as a compressor, is provided. Disclosed embodiments may involve a flow loop that at least in part flows through the interior of the tie bolt or by way of a venting arrangement that at least in part extends through one of the rotor shafts of the rotor structure. Disclosed embodiments may further benefit from seal elements that may be arranged to inhibit passage onto respective hirth couplings of the process fluid being processed by the compressor. In operation, the flow loop may be appropriately pressurized to keep any residual seal leakage that may develop in one or more of the seal elements from travelling onto the hirth couplings.

A vacuum pump that is suitable to achieve uniformity of pressure in the chamber and improve the compression ratio, and a vacuum exhaust system using the vacuum pump. A vacuum pump includes: a cylindrical inner housing; a cylindrical stator placed outside the inner housing; a cylindrical shaft rotationally disposed between the inner housing and the stator; a motor configured to drive and rotate the shaft about an axis thereof; rotor blades in multiple stages disposed on an outer circumference surface of the shaft; and a cylindrical outer housing that is disposed outside the rotor blades in multiple stages and has an inlet port and an outlet port. A seal mechanism is provided in a gap between an outer circumference surface of the inner housing and an inner circumference surface of the shaft to inhibit an inflow of gas into the gap.