A compressor includes a first scroll and a second scroll engaged with the first scroll for performing an orbiting motion relative to the first scroll to form a compression chamber along with the first scroll. A stator is disposed at one side of the second scroll and includes a stator core. A rotor is rotatably disposed inside the stator core, and includes a rotor core. A rotary shaft has one end portion eccentrically coupled to the second scroll and the other end portion coupled to the rotor core. The rotor core is formed with at least one space portion axially recessed into the rotor core.

A rotary piston compressor/pump/blower includes a housing spatially limiting a working chamber, an intake connection for guiding fluid into the working chamber, a pressure connection for guiding the fluid out of the working chamber, and a rotor assembly having a first rotor rotatably arranged in a first working sub-chamber and a second rotor cooperating with the first rotor and rotatably arranged in a second working sub-chamber. The rotary piston compressor/pump/blower also includes a ventilation channel, formed in the housing and connected to the working chamber via a ventilation channel opening, for the temporally limited introducing of air into the working chamber, wherein the ventilation channel opening is open at least in sections, in particular completely open, in a compression phase.

A rotary piston compressor/pump/blower includes a housing spatially limiting a working chamber, an intake connection for guiding fluid into the working chamber, a pressure connection for guiding the fluid out of the working chamber, and a rotor assembly having a first rotor rotatably arranged in a first working sub-chamber and a second rotor cooperating with the first rotor and rotatably arranged in a second working sub-chamber. The rotary piston compressor/pump/blower also includes a ventilation channel, formed in the housing and connected to the working chamber via a ventilation channel opening, for the temporally limited introducing of air into the working chamber, wherein the ventilation channel opening is open at least in sections, in particular completely open, in a compression phase.

A vane-type compressor is provided. The vane-type compressor may include a cylindrical cylinder having opposite open ends along an axial direction, an inner circumferential surface of the cylinder being eccentric from an outer circumferential surface of the cylinder, a main bearing and a sub bearing, respectively, positioned at the open ends of the cylinder, a rotor coupled to a shaft supported by the main bearing and the sub bearing and installed eccentric from the inner circumferential surface of the cylinder, and a plurality of vanes coupled to the rotor to rotate along with the rotor, the plurality of vanes dividing the inner circumferential surface of the cylinder into a plurality of spaces including a suction chamber and a compression chamber when the rotor rotates. An elastic member may be installed at a point at which a minimum gap is maintained between the inner circumferential surface of the cylinder and the rotor so that a portion of the elastic member protrudes inward of the inner circumferential surface of the cylinder. An end of a discharge dimple formed in the inner circumferential surface of the cylinder extends up to the point.

A gas meter with a rated maximum flow capacity of greater than 3,000 CFH (Cubic Feet per Hour)—for example, between 3,500 CFH and 7,000 CFH—is provided with 2-inch flange connectors. One or more undercuts are provided in the meter body to promote satisfactory performance in terms of, for example, differential pressures at the meter inlet and outlet.

A pump includes a rotor and a pump housing. The rotor is rotatable about a rotation axis and comprises a rotor hub and a rotor collar. The rotor collar extends from the rotor hub in the radial direction and encircles the rotor hub in an undulating manner. The pump housing comprises a first axial housing component, a central annular housing component, and a second axial housing component. A pump duct is formed (i) in the axial direction by the first and second housing components and (ii) in the radial direction by the central annular housing component and the rotor.

It is assumed that a distance between a center portion of fixed scroll end plate and an outer peripheral portion at a distal end of fixed spiral wrap of fixed scroll is Ds, and that a distance between a center portion of orbiting scroll end plate and a portion included in a bottom face of an orbiting spiral wrap of orbiting scroll and facing the outer peripheral portion at the distal end of the fixed spiral wrap of the fixed scroll is Do. Further, assuming that an orbiting radius of orbiting scroll is ε, the orbiting radius being a distance between a center of eccentric shaft and a center of driving shaft, a relationship Ds+ε≤Do is satisfied.

A pin-ring mechanism that transmits driving force to cause a driving-side scroll member and a driven-side scroll member to perform rotational movement in a same direction at a same angular velocity is provided. A driving-side end plate includes a ring member installation hole into which a ring member is inserted and installed. The ring member installation hole includes a non-wall-side hole part and a wall-side hole part. The non-wall-side hole part is formed from a non-wall-side surface and has a diameter corresponding to an outer diameter of the ring member. The wall-side hole part is formed from a wall-side surface and has a diameter smaller than the outer diameter of the ring member.

A scroll compressor includes a fixed scroll fixed inside a housing, an orbiting scroll configured to orbit engaged with the fixed scroll, a rotary shaft configured to allow the orbiting scroll to orbit by supporting the orbiting scroll with an eccentric shaft eccentric from a main shaft, and a slide bush portion installed between a bearing of the orbiting scroll and the eccentric shaft and according to a rotational speed of the rotary shaft, configured to change a pressing force of the orbiting scroll applied to the fixed scroll by allowing an eccentricity to be changed by a gas load applied to the orbiting scroll.

A vane-type compressor is provided. The vane-type compressor may include a cylindrical cylinder having opposite open ends along an axial direction, an inner circumferential surface of the cylinder being eccentric from an outer circumferential surface of the cylinder, a main bearing and a sub bearing, respectively, positioned at the open ends of the cylinder, a rotor coupled to a shaft supported by the main bearing and the sub bearing and installed eccentric from the inner circumferential surface of the cylinder, and a plurality of vanes coupled to the rotor to rotate along with the rotor, the plurality of vanes dividing the inner circumferential surface of the cylinder into a plurality of spaces including a suction chamber and a compression chamber when the rotor rotates. An elastic member may be installed at a point at which a minimum gap is maintained between the inner circumferential surface of the cylinder and the rotor so that a portion of the elastic member protrudes inward of the inner circumferential surface of the cylinder. An end of a discharge dimple formed in the inner circumferential surface of the cylinder extends up to the point.