Provided is an internal gear pump. The shape of any one of a plurality of external teeth and a plurality of internal teeth of the pump is formed on the basis of formulae (1)-(5). Formula (1): r=ro−dr.Math.cos θ, Formula (2): Px=(ro−dr)+1/4 dr{1−cos (2θ)}, Formula (3): Py=1/4 dr{−2θ+sin (2θ)}, Formula (4): Qx=Px−r.Math.cos θ, Formula (5): Qy=Py+r.Math.sin θ.

A pumping installation includes at least one first positive-displacement machine and one second positive-displacement machine, as well as a control module, in which installation a gas is evacuated from an enclosed volume by means of the first positive-displacement machine and/or the second positive-displacement machine. The pumping installation includes at least one control valve controlled by the control module and a pressure sensor for sensing the value of the pressure at the outlet of the first positive-displacement machine and/or a temperature sensor for sensing the value of the temperature at the outlet of the first positive-displacement machine in order to control the flow of gas between the enclosed volume and the outlet of the pumping installation.

A pumping installation includes at least one first positive-displacement machine and one second positive-displacement machine, as well as a control module, in which installation a gas is evacuated from an enclosed volume by means of the first positive-displacement machine and/or the second positive-displacement machine. The pumping installation includes at least one control valve controlled by the control module and a pressure sensor for sensing the value of the pressure at the outlet of the first positive-displacement machine and/or a temperature sensor for sensing the value of the temperature at the outlet of the first positive-displacement machine in order to control the flow of gas between the enclosed volume and the outlet of the pumping installation.

A scroll compressor includes an orbiting bedplate. The orbiting bedplate has: an oil passage through which oil supplied from an oil supply passage flows outward in a radial direction of the orbiting bedplate; a lap-side oil supply hole that causes the oil passage to communicate with a lap-formation surface of the orbiting lap at which the orbiting lap is formed; and a thrust-surface-side oil supply hole that causes the oil passage to communicate with a thrust surface of the orbiting bedplate that is opposite to the lap-formation surface of the orbiting bedplate. In the oil passage, an opening and closing mechanism is provided. The opening and closing mechanism closes the thrust-surface-side oil supply hole when the pressure of oil that is drawn from an oil sump by an oil pump and supplied into the oil passage is low, and opens the thrust-surface-side oil supply hole when the pressure of the oil is high.

A scroll compressor includes an orbiting bedplate. The orbiting bedplate has: an oil passage through which oil supplied from an oil supply passage flows outward in a radial direction of the orbiting bedplate; a lap-side oil supply hole that causes the oil passage to communicate with a lap-formation surface of the orbiting lap at which the orbiting lap is formed; and a thrust-surface-side oil supply hole that causes the oil passage to communicate with a thrust surface of the orbiting bedplate that is opposite to the lap-formation surface of the orbiting bedplate. In the oil passage, an opening and closing mechanism is provided. The opening and closing mechanism closes the thrust-surface-side oil supply hole when the pressure of oil that is drawn from an oil sump by an oil pump and supplied into the oil passage is low, and opens the thrust-surface-side oil supply hole when the pressure of the oil is high.

A hermetic compressor includes a casing, a cylinder in the casing, a first bearing and a second bearing defining a compression space together with the cylinder, a roller located at an eccentric position with respect to an inner surface of the cylinder and configured to vary a volume of the compression space, and a vane inserted into the roller to rotate together with the roller, and drawn out toward the inner surface of the cylinder to divide the compression space into compression chambers. An inlet port in communication with the compression space is defined in the first bearing, and an intermediate plate is located between the cylinder and the inlet port and defines a suction passage connected to the inlet port, where a peripheral length of an inner peripheral surface of the suction passage is greater than a peripheral length of an outer peripheral surface of the suction passage.

A hermetic compressor includes a casing, a cylinder in the casing, a first bearing and a second bearing defining a compression space together with the cylinder, a roller located at an eccentric position with respect to an inner surface of the cylinder and configured to vary a volume of the compression space, and a vane inserted into the roller to rotate together with the roller, and drawn out toward the inner surface of the cylinder to divide the compression space into compression chambers. An inlet port in communication with the compression space is defined in the first bearing, and an intermediate plate is located between the cylinder and the inlet port and defines a suction passage connected to the inlet port, where a peripheral length of an inner peripheral surface of the suction passage is greater than a peripheral length of an outer peripheral surface of the suction passage.

A hermetic compressor includes a casing, a cylinder in the casing, a first bearing and a second bearing defining a compression space together with the cylinder, a roller located at an eccentric position with respect to an inner surface of the cylinder and configured to vary a volume of the compression space, and a vane inserted into the roller to rotate together with the roller, and drawn out toward the inner surface of the cylinder to divide the compression space into compression chambers. An inlet port in communication with the compression space is defined in the first bearing, and an intermediate plate is located between the cylinder and the inlet port and defines a suction passage connected to the inlet port, where a peripheral length of an inner peripheral surface of the suction passage is greater than a peripheral length of an outer peripheral surface of the suction passage.

A hermetic compressor includes a casing, a cylinder in the casing, a first bearing and a second bearing defining a compression space together with the cylinder, a roller located at an eccentric position with respect to an inner surface of the cylinder and configured to vary a volume of the compression space, and a vane inserted into the roller to rotate together with the roller, and drawn out toward the inner surface of the cylinder to divide the compression space into compression chambers. An inlet port in communication with the compression space is defined in the first bearing, and an intermediate plate is located between the cylinder and the inlet port and defines a suction passage connected to the inlet port, where a peripheral length of an inner peripheral surface of the suction passage is greater than a peripheral length of an outer peripheral surface of the suction passage.

A hermetic compressor includes a casing, a cylinder in the casing, a first bearing and a second bearing defining a compression space together with the cylinder, a roller located at an eccentric position with respect to an inner surface of the cylinder and configured to vary a volume of the compression space, and a vane inserted into the roller to rotate together with the roller, and drawn out toward the inner surface of the cylinder to divide the compression space into compression chambers. An inlet port in communication with the compression space is defined in the first bearing, and an intermediate plate is located between the cylinder and the inlet port and defines a suction passage connected to the inlet port, where a peripheral length of an inner peripheral surface of the suction passage is greater than a peripheral length of an outer peripheral surface of the suction passage.