US 11,994,127 B2
Multistage compression system
Daisuke Okamoto, Osaka (JP); Naoto Tomioka, Osaka (JP); Mikio Kajiwara, Osaka (JP); Yohei Nishide, Osaka (JP); Yousuke Ohnishi, Osaka (JP); and Masaaki Adachi, Osaka (JP)
Assigned to Daikin Industries, Ltd., Osaka (JP)
Appl. No. 17/280,078
Filed by DAIKIN INDUSTRIES, LTD., Osaka (JP)
PCT Filed Sep. 25, 2019, PCT No. PCT/JP2019/037669
§ 371(c)(1), (2) Date Mar. 25, 2021,
PCT Pub. No. WO2020/067194, PCT Pub. Date Apr. 2, 2020.
Claims priority of application No. 2018-185073 (JP), filed on Sep. 28, 2018; application No. 2018-221585 (JP), filed on Nov. 27, 2018; application No. 2018-233787 (JP), filed on Dec. 13, 2018; and application No. 2018-233790 (JP), filed on Dec. 13, 2018.
Prior Publication US 2021/0340981 A1, Nov. 4, 2021
Int. Cl. F04C 23/02 (2006.01); F04C 18/356 (2006.01); F04C 23/00 (2006.01); F04C 29/02 (2006.01); F04C 29/04 (2006.01); F25B 1/04 (2006.01); F25B 1/10 (2006.01); F25B 13/00 (2006.01); F25B 31/00 (2006.01)
CPC F04C 23/02 (2013.01) [F04C 18/356 (2013.01); F04C 18/3564 (2013.01); F04C 23/00 (2013.01); F04C 23/001 (2013.01); F04C 23/008 (2013.01); F04C 29/02 (2013.01); F04C 29/04 (2013.01); F25B 1/04 (2013.01); F25B 1/10 (2013.01); F25B 13/00 (2013.01); F25B 31/004 (2013.01); F04C 2210/222 (2013.01); F04C 2240/30 (2013.01); F04C 2240/804 (2013.01); F25B 2400/04 (2013.01); F25B 2400/072 (2013.01); F25B 2400/13 (2013.01); F25B 2400/23 (2013.01); F25B 2700/21152 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A multistage compression system using refrigerant and oil, the multistage compression system comprising:
a low-stage compressor configured to compress the refrigerant;
a high-stage compressor configured to further compress the refrigerant compressed by the low-stage compressor; and
an oil return pipe configured to return the oil discharged by the high-stage compressor e oil in the high-stage compressor to the low-stage compressor,
the low-stage compressor having
a compression part configured to compress the refrigerant, the compression part being a rotary compression part, the compression part including a compression chamber, the refrigerant being introduced into and compressed in the compression chamber,
a motor configured to drive the compression part, the motor being disposed above the compression part, and
a container housing the compression part and the motor, and
the oil return pipe being connected to a space below the motor inside the container, and the oil return pipe being connected above the compression chamber to the container.