Abstract: The present invention relates to an electric acoustic converter used as a speaker or a receiver of a mobile communication device such as a portable telephone or the like. In the electric acoustic converter according to the present invention, the size reduction and thinning of the thickness of the electric acoustic converter can be promoted by providing surface-like rear surface terminals 81 and 82 on the exposed surface 33 which is a rear surface of the yoke 3.

Abstract: An oil recovery system for a closed type centrifugal refrigerating machine. The refrigerating machine includes a compressor that has an oil sump below the suction side thereof, a condenser that liquefies compressed refrigerant gas by cooling, an evaporator that evaporates the liquefied refrigerant, a suction volume control valve that controls the volumetric flow of refrigerant gas sucked into the compressor from the evaporator, recovery means for recovering oil from the oil sump to an oil tank in a lubricating system, and control means for starting or stopping the compressor in accordance with the magnitude of refrigeration load. The oil recovery system comprises valve opening control means for controlling the opening of the suction volume control valve such that a decrease in the amount of oil recovered to the oil tank is compensated for when the number of times of start or stop of the compressor per unit of time exceeds a set number.

Abstract: A liquid filled evaporator of the shell and tube type is disclosed which is capable of distributing refrigerant liquid over an overall heat exchanger tube nest to significantly improve the heat exchanging and substantially decreasing the overall dimensions of the evaporator. The evaporator comprises a drum shell formed into substantially a rectangular shape in vertical section and to extend in the lateral direction.

Abstract: A device for collecting lubricating oil in the turbo-refrigerator comprising an evaporator, a condenser, a compressor, a suction vane arranged in front of the compressor to control the amount of refrigerant gas sucked, a mechanism for returning the lubricating oil, which remains in a space located downstream the suction vane, back to an oil reservoir, and a tube for communicating the space located downstream the suction vane with a space on the evaporation surface of the evaporator.

Abstract: A motor cooling apparatus for use with the refrigerator which includes an evaporator, a condenser, a compressor and a main motor adapted to actuate the compressor and connected to the condenser at the internal space thereof. The motor cooling apparatus includes a refrigerant liquid guide passage for guiding refrigerant liquid condensed in the condenser to the internal space of the main motor by means of a refrigerant pump; a first opening formed in the condenser and connected to the internal space of the main motor; and a second opening formed at the bottom of the condenser and connected to the evaporator. The condenser has a reservoir at the bottom thereof to stock the refrigerant liquid. The reservoir is located between the first and second openings in the longitudinal direction of the condenser and connected to the refrigerant liquid guide passage on the suction side of the refrigerant pump. The reservoir may be formed at the same position as where the second opening is formed.