Abstract: X-ray tube noise is reduced by coupling the stator mass to the neck section of the glass vacuum tube so that vibrations are dissipated by the stator and not transmitted to the bulk of the vacuum tube. The coupling is accomplished with a non-magnetic sealing material such as an epoxy sealant. The sealant will generally fill the gap between the stator and the neck section of the vacuum tube. Alternatively, the coupling can be done with a mechanical clamping device.

Abstract: Noise is reduced in an X-ray tube by inserting a non-glass insert between sections of the glass vacuum tube. The non-glass insert has an impedance which is significantly different than the impedance of the glass tube sections. This impedance mismatch inhibits vibration energy from passing from one glass section to the other. In addition to having a different impedance than the glass sections, the non-glass insert can be made of a heavier material, thus presenting sufficient mass to dissipate vibration energy. The non-glass insert is connected to the glass sections by a pair of connecting members, each of which has a coefficient of thermal expansion closely matching that of the glass sections. Each connecting member has a ring with an annular flange extending perpendicularly therefrom. The ring of each connecting member is attached a respective one of the glass sections and each flange is attached to the insert.

Abstract: An arrangement for reducing noise in an X-ray tube uses a ring mass disposed on the bearing shroud. The ring mass dissipates vibrational energy which would otherwise be transmitted to the glass envelope of the vacuum tube within the casing of the X-ray tube. The ring mass, which is tightly coupled to the bearing shroud, is mounted adjacent the neck of the glass envelope of the vacuum tube. The ring mass is made of lead and may have two ends at a split so that a bolt may tighten the ring around the bearing shroud.

Abstract: Noise reduction is provided in a rotary compressor by selecting the location of the opening of the discharge port so as to minimize the transmission of noise by the discharge compressed gasses. In particular, the discharge port opening is located in the middle (i.e., in an axial direction) of the cylinder wall of the rotary compressor corresponding to a node in a first thickness mode standing wave. This corresponds to 1/4 wavelength relative to the thickness mode standing wave from the end plate. Additionally, the opening is located 1/4 wavelength from the corner or edge at which the sliding vane is positioned, this ensuring that the opening is at a node in a first cylindrical mode standing wave set up in the compression chamber. The discharge port includes a passage extending through the cylindrical wall and a passage extending through the end plate.

Abstract: A Helmholtz resonator is used in communication with the compression chamber of a rotary compressor in order to attenuate noise. The resonator concentrates the attenuation of noise in a frequency band around 4 kHz corresponding to the concentration of noise produced by a particular rotary compressor, this band also corresponding to the frequencies which the human ears are most sensitive to. The resonator branches off from the discharge port in an end wall of the compressor. The resonantor uses an easily machined cylindrical resonance cavity on the surface of the end wall, the resonance cavity also being bounded on one side by a cylindrical wall of the rotary compressor. The resonator significantly reduces the noise in a rotary compressor of a specific type commonly used for compressing refrigerant gases in a refrigerator.