The present disclosure relates to an electric pump including a housing defining an inlet and an outlet. The electric pump includes a rotor and stator within the housing. The rotor is liquid cooled by working fluid of the pump and the stator is positioned in a dry chamber that is sealed to prevent the working fluid from entering the dry chamber. A heat exchanger is used to cool the stator. An impeller driven by the rotor draws working fluid into the housing through the inlet. The working fluid passes through the heat exchanger to draw heat from the stator before reaching the impeller. The working fluid is discharged from the housing through the outlet by the impeller.

Systems and features for improving sand control in pumps are provided. These features can be used in centrifugal pumps employed in a variety of oilfield applications, such as in electric submersible pumping systems positioned downhole in a wellbore to pump oil or other fluids. Such features include shielded anti-swirl ribs positioned in the balance chamber.

An electric submersible pump assembly with upthrust protection is described. The described pump assembly, modules, and components may be used for operating an electric submersible pump at high speeds as well as over a wide range of speeds and flowrates without replacing downhole equipment. The described pump assembly may be shorter than comparable pump assemblies and may be assembled offsite, thereby leading to faster and easier installation with less down time. By operating over a wide range of speeds, the disclosed pump assembly allows the operator to reduce overall inventory, reduce down time for the well, and avoid other complications associated with replacing a pump assembly or other downhole components.

An electric submersible pumping system is constructed with an outer housing which contains an integrated pump and motor. The pump may comprise an impeller disposed within a stator of the motor to form an integrated pump and the motor. An electric submersible pumping system includes a stator having a passage extending longitudinally through the stator. A plurality of stages, including impellers and diffusers, are disposed within the passage.

An electric submersible pumping system is constructed with an outer housing which contains an integrated pump and motor. The pump may comprise an impeller disposed within a stator of the motor to form an integrated pump and the motor. An electric submersible pumping system includes a stator having a passage extending longitudinally through the stator. A plurality of stages, including impellers and diffusers, are disposed within the passage.

A tool includes a device including a housing and a rotor, the rotor to rotate about a longitudinal axis, and an axial gap generator including a stator assembly positioned adjacent to the rotor. The axial gap generator generates a voltage signal as a function of a gap spacing between the stator assembly and the rotor, the gap spacing being parallel to the longitudinal axis.

A tool includes a device including a housing and a rotor, the rotor to rotate about a longitudinal axis, and an axial gap generator including a stator assembly positioned adjacent to the rotor. The axial gap generator generates a voltage signal as a function of a gap spacing between the stator assembly and the rotor, the gap spacing being parallel to the longitudinal axis.

A compressor that vibrates a rotary shaft or changes an operating frequency of a motor, in response to a vibration frequency of a discharge passage falling outside of a normal range. The compressor may include one or more impeller configured to draw in and compress refrigerant; a motor configured to rotate the one or more impeller; a rotary shaft, to which the one or more impeller and the motor are coupled; at least two thrust bearings that limit vibration of the rotary shaft; a vibration measuring sensor configured to measure a vibration frequency of a discharge passage; and a controller configured to control the at least two thrust bearings based on the vibration frequency. Upon determining that the vibration frequency falls outside of a normal vibration frequency range, the controller controls the at least two thrust bearings to vibrate the rotary shaft a predetermined number of times.

A multistage centrifugal pump for conveying a fluid includes a pump housing, two first stage impellers, a last stage impeller and a shaft. The two first stage impellers and the last stage impeller convey the fluid from a housing inlet to a housing outlet. The shaft rotates each impeller about an axial direction, each impeller comprising a suction side to receive the fluid and a discharge side to discharge the fluid. The last stage impeller is a double suction impeller, having a first suction side and a second suction side, and the last stage impeller is arranged between the two first stage impellers with respect to the axial direction. Each impeller of the two first stage impellers is arranged with the suction side of a respective first stage impeller facing one of the first and second suction sides of the last stage impeller.

Apparatus comprising and methods are described including a blood pump that includes an axial shaft, and an impeller disposed on the axial shaft. The impeller is configured to pump blood of the subject by rotating. The impeller and the axial shaft are configured to undergo axial back-and-forth motion during operation of the impeller. A distal tip element is disposed at a distal end of the blood pump. The distal tip element defines an axial-shaft-receiving tube, configured to receive at least a portion of the axial shaft during forward motion of the axial shaft. The distal tip element additionally defines an atraumatic distal tip portion disposed distally of the axial-shaft-receiving tube. Other applications are also described.