The present embodiments disclose a mechanical shaft lock for use in electric submersible pumps. The mechanical shaft lock can include one or more shear pins. When an end of the shear pin, e.g., shear pin head, lines up with one or more shearing slots on the MSL or pump shaft, the shear pin engages and stops the rotation of the pump shaft and motor attached to the pump. The shaft lock can be engaged for installing an ESP, disengaged for production after installing by breaking the shear pin upon start-up, and re-engaged for removing the ESP from the wellbore. In some embodiments, the MSL may be configured to be disengaged and re-engaged to deal with well kicks.

A method for leak detection in a system including a compressor. A first pressure differential is determined in the system via a first pressure differential indicator (PDI). The first pressure differential is converted into a first flow measurement. A second flow measurement is determined downstream of the compressor using a second PDI. The first flow measurement and the second flow measurement are compared to determine whether a leak exists between the first PDI and the second PDI.

An illustrative example embodiment of a compressor assembly includes a compressor housing having a suction inlet and a discharge outlet. A flow restricting valve allows unrestricted fluid flow in a first direction into the housing through the suction inlet and out of the discharge outlet during a first operating condition. The flow restricting valve allows a restricted fluid flow in a second, opposite direction into the housing through the discharge outlet in a second operating condition.

A control device includes: a variation command unit that changes a command value, which is a command value sent to a system including a compressor, affecting an operating state of the compressor; a proportional coefficient calculation unit that calculates a proportional coefficient of a variation in a parameter, which indicates a state of the compressor or an electric motor that drives the compressor when the system is operated based on the command value, with respect to the command value; and a control unit that performs control for avoiding or suppressing surging in the compressor, based on a value of the proportional coefficient.

An HVAC system includes an unloading device, a centrifugal compressor, a gas foil bearing, a VFD and a controller. The controller is programmed to start the centrifugal compressor from a stopped condition by operating the unloading device to remove a load from the centrifugal compressor, accelerating the motor to a first speed above a liftoff speed of the gas foil bearing and below an operating speed of the centrifugal compressor, running the motor for a period of time, operating the unloading device to apply the load to the centrifugal compressor, and accelerating the motor to the operating speed.

A control system for a gas turbine includes a processor. The processor configured to access one or more operating parameters of the gas turbine. The operating parameters are configured to specify how the gas turbine operates. The processor is configured to predict a rate of degradation to one or more parts of a compressor of the gas turbine due to one or more effects on the parts by operating the gas turbine according to the one or more operating parameters. The processor is configured to send an alert to an electronic device based at least in part on the rate of degradation of the compressor.

A blade includes an aerodynamic portion (21) and an assembly of the aerodynamic portion to a blade shank retaining the aerodynamic portion in a radial direction (23). The blade shank includes at least one passage restriction in at least one retention direction orthogonal to the radial direction, having a restricted width allowing the aerodynamic portion (21) to pass through. The base of the aerodynamic portion (21) has an overall dimension which is strictly greater than the restricted width so that, in the event of rupture of the assembly, the base is able to come into abutment against the passage restriction so as to retain the aerodynamic portion (21) in the blade shank (20).

A ventilation fan includes a shaft, a rotor, a motor housing, a bearing housing, and an air bearing. The shaft has a shaft body that extends between a first shaft end and a second shaft end. The shaft body defines a first port and a bore. The rotor is disposed about the shaft. The motor housing is disposed about the shaft and is axially spaced apart from the rotor. The bearing housing is disposed about the shaft. The air bearing is disposed proximate the second shaft end and is disposed between the bearing arm and the second shaft end.

A state observation device (30) uses an ADC (37) to digitize a detection signal from a gap sensor (21) at a low-speed sampling period and uses a separation unit (38) to separate the digitized detection signal into vane detection signals considered to be for the detection of a vane of a compressor impeller and non-vane detection signals considered not to be for the detection of a vane. Further, the determination unit (39) extracts a vane peak detection signal considered to be for a vane peak by comparing a vane detection signal with vane detection signals corresponding to other vanes and non-vane detection signals, and a shaft vibration and tip clearance are determined as states of the compressor impeller on the basis of the extracted vane peak detection signal. Thus, the state observation device (30) is capable of observing the state of a rotary machine without carrying out high-speed sampling.

A seal includes a mating ring that rotates relative to a porous carbon primary ring at a seal interface. A buffer gas is provided into the seal and passes from the back of the primary ring to the seal interface. The seal can be used as a separation seal or in combination with another seal.