A silencer for vacuum pumps which allows only for unidirectional flow and which reduces the noises caused by the air discharged at the exhaust of said pump. The silencer features baffles to divert and disrupt the flow and an umbrella check valve to ensure the unidirectionality of the discharge flow.

Disclosed herein is a rotary compressor capable of maintaining the overall dynamic balance and providing low vibration and low noise even at high speed operation and capable of improving efficiency by providing a communication passage to communicate operation chambers, which are provided inside each of the plurality of cylinders for compressing a refrigerant, to each other. The rotary-type compressor includes a housing, a drive motor provided inside the housing to generate power and having a stator and a rotor, and a compression unit that receives power from the drive motor and compresses the refrigerant. The compression unit includes a plurality of cylinders in which an operation chamber to compress the refrigerant is provided. The operation chambers provided in each of the plurality of cylinders are provided to have different volumes, and a balancer provided to maintain dynamic balance is provided only in the lower side of the rotor.

A vacuum roots blower includes a rotor capable of being rotated to capture a gas from an inlet and further rotated to discharge the captured gas from an outlet. The captured gas is held within a pocket formed between lobes of the rotor and the adjacent housing within which the rotor is rotated. The vacuum roots blower includes a pressure relief system capable of delivering a pressure relief gas to the pocket. The pressure relief system includes a sonic passage structured to produce a choked flow condition as the pressure relief system fills the pocket with pressure relief gas. In one form the pressure relief gas can be a cooling gas, but other forms such as ambient air are also contemplated.

A compressor is configured such that an axis center of a rotating shaft for transmitting rotation of a rotor to a compressing unit for compressing a refrigerant is offset from a rotor center of the rotor, and, when the rotor is divided into, with respect to the rotor center, a first portion located on a side in a direction from the axis center to the rotor center and a second portion located on a side in a direction from the rotor center to the axis center, a magnetic force of the first portion is stronger than a magnetic force of the second portion. This configuration allows the rotor to generate non-uniform magnetic attractive forces during the rotation of the rotor and thereby can suppress vibration generated due to rotation of an eccentric portion of the compressing unit and reduce noise.

A vacuum roots blower includes a rotor capable of being rotated to capture a gas from an inlet and further rotated to discharge the captured gas from an outlet. The captured gas is held within a pocket formed between lobes of the rotor and the adjacent housing within which the rotor is rotated. The vacuum roots blower includes a pressure relief system capable of delivering a pressure relief gas to the pocket. The pressure relief system includes a sonic passage structured to produce a choked flow condition as the pressure relief system fills the pocket with pressure relief gas. In one form the pressure relief gas can be a cooling gas, but other forms such as ambient air are also contemplated.

Scroll compressor designs are provided to minimize vibration, sound, and noise transmission. The scroll compressor has a bearing housing, and orbiting and non-orbiting scroll members. The non-orbiting scroll member has a radially extending flanged portion with at least one aperture substantially aligned with the axially extending bore. At least one fastener is disposed within the aperture and the bore. A sound isolation member contacts at least one of the non-orbiting scroll member, the fastener, or the bearing housing, to reduce or eliminate noise transmission. The sound isolation member may be formed of a polymeric composite having an acoustic impedance value greater than the surrounding materials. The sound isolation member may be an annular washer, an O-ring, or a biasing member, by way of non-limiting example. In other variations, fluid passages are provided within the fastener and/or bearing housing to facilitate entry of lubricant oil to further dampen sound and noise.

A fluid compressor is provided. The fluid compressor includes a case including an inlet configured to introduce fluid to be compressed, a compression unit including a compression chamber configured to compress the fluid introduced into the case, and a discharge port configured to discharge the compressed fluid to the outside of the compression chamber, a motor configured to drive the compression unit, and a valve configured to open and close the discharge port. The valve includes a fastening portion coupled to the compression unit to be spaced a first distance from the discharge port.

Scroll compressor designs are provided to minimize vibration, sound, and noise transmission. The scroll compressor has a bearing housing, and orbiting and non-orbiting scroll members. The non-orbiting scroll member has a radially extending flanged portion with at least one aperture substantially aligned with the axially extending bore. At least one fastener is disposed within the aperture and the bore. A sound isolation member contacts at least one of the non-orbiting scroll member, the fastener, or the bearing housing, to reduce or eliminate noise transmission. The sound isolation member may be formed of a polymeric composite having an acoustic impedance value greater than the surrounding materials. The sound isolation member may be an annular washer, an O-ring, or a biasing member, by way of non-limiting example. In other variations, fluid passages are provided within the fastener and/or bearing housing to facilitate entry of lubricant oil to further dampen sound and noise.

A screw compressor for a utility vehicle has at least one female screw, at least one male screw that meshes with the female screw, and at least one screw compressor drive which drives the female screw.

A pair of intermeshing gears for multi-shaft vacuum pumps, comprising a first running gear and a second running gear is provided, wherein at least the first running gear comprises a first and a second gearwheel, respectively. The first and the second gearwheel are axially arranged in direct contact, wherein the first gearwheel comprises a predetermined number of first cogs of same dimension and the second gearwheel comprises a predetermined number of second cogs, wherein the predetermined number of second cogs is at least one. All of the predetermined number of first cogs have a dimension larger than the dimension of the predetermined number of second cogs to a predetermined amount. The first gearwheel is made of a material with a first elastic modulus. The second gearwheel is made of a material with a second elastic modulus, wherein the first and the second elastic modulus are different.