Patent ID: 8435014
Filing Date: 2013-05-07
Classification: F04C

Abstract:
1. A hermetically sealed scroll compressor for compressing a gas, comprising, a compression mechanism including a fixed scroll having a disk shaped mirror plate, a spiral wrap projecting from the disk shaped mirror plate, an intake port for taking the gas into the compression mechanism, and a discharge port for discharging the compressed gas from the compression mechanism, and an orbital scroll which is capable of orbiting with respect to the fixed scroll while being prevented from rotating on an axis of the orbital scroll and which has another disk shaped mirror plate and another spiral wrap projecting from the another disk shaped mirror plate to engage with the spiral wrap so that a first compression chamber is formed between a radially outer side surface of the another spiral wrap and a radially inner side surface of the spiral wrap, a second compression chamber is formed between a radially inner side surface of the another spiral wrap and a radially outer side surface of the spiral wrap, and each of the first and second compression chambers moves radially inward to decrease in its volume to compress therein the gas taken from the intake port to be discharged from the discharge port, an electric motor for driving the compression mechanism so that the orbital scroll orbits with respect to the fixed scroll, a hermetically sealed container containing therein the compression mechanism and the electric motor, and an injection mechanism including an injection port opening on the disk shaped mirror plate to supply a fluid into the gas in the first and second compression chambers, wherein the gas includes helium, the fluid includes oil, the injection port has first and second injection port portions juxtaposed to each other so that the another spiral wrap is movable between the first and second injection port portions while the spiral wrap is prevented from extending between the first and second injection port portions, the radially outer side surface of the another spiral wrap at a radially outer end portion of spiral shape of the another spiral wrap contacts the radially inner side surface of the spiral wrap at a first contact point to make a volume of the first compression chamber maximum, the radially inner side surface of the another spiral wrap at the radially outer end portion of the spiral shape of the another spiral wrap contacts the radially outer side surface of the spiral wrap at a second contact point to make a volume of the second compression chamber maximum, a winding angle of the spiral wrap at the first contact point is extended angularly by a predetermined angle with respect to a winding angle of the spiral wrap at the second contact point, and each of a winding angle of the another spiral wrap at the first contact point and a winding angle of the another spiral wrap at the second contact point is angularly identical to the winding angle of the spiral wrap at the first contact point so that a rotational phase difference of 180 degrees is generated between timings of intake completions of the first compression chamber and the second compression chamber; and wherein an arc radius Rs