The invention in question pertains to the technological field of refrigeration compressors. A hermetic compressor for positive displacement is disclosed whose airtight housing is specially altered so that its natural frequencies of vibration are distributed at frequencies above 4200 Hz and whose “capacitance density” is greater than 160 W/L.

Systems and methods to isolate a vibration source (e.g., a compressor) externally are disclosed. The embodiments generally include preventing/reducing vibration and/or pulsation transmission from the vibration source by one or more functional/structural isolating members, and preventing/reducing sound radiated from the vibration source by one or more sound enclosures.

A pump apparatus which can more accurately determine the occurrence of an abnormal vibration. The pump apparatus includes: a pump; an electric motor for driving the pump; an inverter as a speed changing means for the electric motor; a vibration detector for detecting at least one of a vibration of the pump, a vibration of the electric motor and a vibration of the inverter; and a controller for controlling the pump. The controller includes a storage unit for storing a measured vibration value measured by the vibration detector. The storage unit has a storage table which, when the rotational speed of the pump is increased stepwise to a predetermined rotational speed, stores the measured vibration value measured at each step.

An apparatus for applying a vacuum during a surgical procedure can include a vacuum pump assembly having a port, a first housing, a second housing, a first silencer or tubular magnet and a second silencer. The first housing can define a first cavity receiving the vacuum pump assembly therein. A portion of the first housing can be formed by a portion of the port. The second housing can define a second cavity receiving the first housing therein. A portion of the second housing can be formed by a second portion of the port. The first silencer or tubular magnet can be coupled to the first housing and can have a longitudinal extent along a longitudinal axis. The first silencer or tubular magnet can extend from the first housing within the second cavity. The second silencer can be coupled to the second housing and can have a longitudinal extent along a longitudinal axis. The second silencer can extend from the second housing within second cavity.

An electrically-driven compressor is installed on an engine. Refrigerant is compressed with rotation of a rotating shaft in a compression unit. An electric motor is coupled to the rotating shaft and drives the compression unit through the rotating shaft. A housing accommodates the compression unit, the electric motor, and the motor drive circuit aligned in the listed order in the axial direction of the rotating shaft. The housing is internally provided with the discharge chamber through which the refrigerant compressed by the compression unit is discharged. A weight is attached to the housing and disposed in the discharge chamber in a manner that a resonance frequency of the electrically-driven compressor is shifted relative to a resonance frequency of the engine, the weight including a material having a specific gravity greater than a specific gravity of a constituent material of the housing.

The present disclosure relates to a compressor including a branch part for reducing vibration and noise caused by a refrigerant flowing inside a muffler by expanding an enclosed space formed by a compression part and the muffler in the direction of a rotation axis.

Systems and methods to isolate a vibration source (e.g., a compressor) externally are disclosed. The embodiments generally include preventing/reducing vibration and/or pulsation transmission from the vibration source by one or more functional/structural isolating members, and preventing/reducing sound radiated from the vibration source by one or more sound enclosures.

A method for selecting drilling parameters for drilling a borehole penetrating the earth with a drill string includes: varying a frequency of an excitation force applied to the drill string using an excitation device controlled by a drill string controller and measuring vibration-related amplitudes of the drill string due to the applied excitation force using a vibration sensor to provide amplitude measurements. The method further includes determining one or more modal properties comprising one or more eigenfrequencies of the drill string using the amplitude measurements and selecting drilling parameters that apply an excitation force at a frequency that avoids a selected range of frequencies that bound the one or more eigenfrequencies.

Systems and methods to isolate a vibration source (e.g., a compressor) externally are disclosed. The embodiments generally include preventing/reducing vibration and/or pulsation transmission from the vibration source by one or more functional/structural isolating members, and preventing/reducing sound radiated from the vibration source by one or more sound enclosures.

An electric compressor and a refrigeration device having the same are provided. The electric compressor includes: an electric motor having a stator and a rotor; a compressing mechanism having an eccentric shaft rotatably and slidably connected to the rotor and defining a compressing chamber therein, the compressing chamber being configured to perform a compression by the eccentric shaft; and a torque damping device configured to connect the rotor with the eccentric shaft, in which during the compression of the compressing chamber, a difference between a rotation angle of the eccentric shaft and a rotation angle of the rotor is a phase angle which is increased and decreased.