Abstract: A turbomachine includes a rotary shaft, an impeller, a casing, a prime mover separated from the impeller in an axial direction, and a seal portion sealing between the impeller side and the prime mover side. The impeller has an impeller suction portion into which fluid is sucked and an impeller discharge portion from which the fluid is discharged. The seal portion has a rotary seal portion provided on the rotary shaft and a fixed seal portion provided on the casing. The rotary seal portion and the fixed seal portion are spaced apart from each other in a radial direction, extend in the axial direction, and form a leakage flow path through which the fluid discharged from the impeller discharge portion leaks from the impeller side to the prime mover side. The maximum seal diameter of the leakage flow path is greater than the inlet diameter of the impeller suction portion.

Abstract: A casing of a centrifugal compressor has a first wall facing a back surface of an impeller. A back gap is formed between the back surface of the impeller and the first wall. A specific speed of the impeller is set to be less than 0.1. A ratio of an axial width s of the back gap to an impeller radius r satisfies a relationship of 0.008?s/r?0.5, where the axial width s is a width of the back gap in an axial direction of the shaft, and the impeller radius r is a radius of the impeller.

Abstract: A compressor includes a rotary shaft, a motor to rotate the rotary shaft, and a gas bearing to support the rotary shaft. A passage is provided between a coil of the motor and a housing of the gas bearing. The passage carries a flow of refrigerant to cool the coil of the motor.

Abstract: A turbo-type fluid machine includes a shaft configured to be rotationally driven, a compression mechanism having an impeller, and a coupling portion coupling an end portion of the shaft and the impeller with each other. The coupling portion is provided with a balance adjustment mechanism.

Abstract: A turbo-type fluid machine includes a shaft configured to be rotationally driven, a compression mechanism having an impeller, and a coupling portion coupling an end portion of the shaft and the impeller with each other. The coupling portion is provided with a balance adjustment mechanism.

Abstract: A chromene compound of this invention, as shown in the following formula: characterized by having an indeno(2,1-f)naphtho(1,2-b)pyran structure as a basic structure, and having a substituent which is a substituted or unsubstituted aryl group such as methoxyphenyl group, or a substituted or unsubsterituted heteroaryl group such as thienyl group bonding to a carbon atom at the seventh position of the indeno(2,1-f)naphtho(1,2-b)pyran structure. The photochromic compound exhibits a color tone of a neutral tint when it develops a color, features a high color-developing sensitivity and a high fading rate, and has a good photochromic resistance.

Abstract: A chromene compound of this invention, as shown in the following formula: characterized by having an indeno(2,1-f)naphtho(1,2-b)pyran structure as a basic structure, and having a substituent which is a substituted or unsubstituted aryl group such as methoxyphenyl group, or a substituted or unsubstituted heteroaryl group such as thienyl group bonding to a carbon atom at the seventh position of the indeno(2,1-f)naphtho(1,2-b)pyran structure. The photochromic compound exhibits a color tone of a neutral tint when it develops a color, features a high color-developing sensitivity and a high fading rate, and has a good photochromic resistance.