Abstract: A refrigeration gas compressor comprises a piston reciprocably movable to effect gas compression, a motor-driven rotatable crankshaft, and a connecting rod between a crank pin on the crankshaft, and a wrist pin on the piston. A crank pin receiving hole and a wrist pin receiving hole in opposite ends of the connecting rod are connected by an oil passage. The oil passage is connected to a groove in the upper side wall in the crank pin receiving hole. The crank pin has two lubricating oil supply ports at opposite sides of its outer surface through which lubricating oil is pumped. A bearing assembly comprising semi-circular upper and lower bearing sections is disposed around the crank pin. Each bearing section has a smooth inner surface. The upper bearing section has oil well recesses near, but spaced from, opposite ends of its inner surface which receive oil from the oil supply ports each time a port moves therepast.

Abstract: The invention relates to improvements in a refrigeration system having an oil cooled screw compressor from which mixed oil and compressed refrigerant issues to an oil separator via a discharge duct, and wherein a refrigerant pump draws liquid refrigerant from the high pressure receiver and delivers it to the discharge duct to cool the oil and desuperheat the refrigerant. The refrigerant pump and a hydraulic motor that drives it are in a single sealed housing. The hydraulic motor is energized with pressure oil from the oil pump whereby oil is returned to the compressor from the oil separator. Oil flow to the hydraulic motor is throttled in accordance with output from a temperature sensor at the discharge duct, to maintain a constant temperature of oil-refrigerant mixture passing to the oil separator. A standpipe arrangement prevents cavitation at the refrigerant pump.