PURPOSE: To supply the inside of a shaft seal chamber with an oil impregnating refrigerant in an effective manner, by projectingly installing a choke part between a suction chamber part and a suction passage opening part or a suction chamber facing other bores.
CONSTITUTION: Since the quantity of refrigerant gas flowing from a suction passage 18 to a suction chamber part 17b is restricted in volume by means of a choke part 19, inflow resistance in the refrigerant gas by the choke part 19 does not so matter in time of operation at a low speed whereby the suction of refrigerant gas into a bore 3 is sufficiently achieved but in time of high speed operation, the inflow resistance grows larger due to action in the choke part and thereby the refrigerant gas flowing in from the suction passage 18 gets decreased so that differential pressure lying between the suction chamber part 17b and a sub-suction chamber 17a increases, causing the refrigerant gas flowing in from the sub-suction chamber 17a to the suction chamber part 17b to be increased as well, thus lubrication and cooling for a shaft 23 inside a shaft seal chamber 14 sufficiently take place.
MORI SHIGEO
OONO MAKOTO
