Abstract: An apparatus for controlling a discharge pressure of a fluid includes: a pump configured to suck the fluid through an inlet or to discharge the sucked fluid through an outlet; a distributor connected to the pump and to an injection nozzle provided by a sensor and configured to distribute the fluid discharged from the pump to the sensor; and a controller. The controller is configured to control the pump to operate selectively in accordance with detection of contamination of the sensor and to control operation of the distributor to be forcibly delayed during operation of the pump such that the fluid distributed to the sensor, when detected as being contaminated, is controlled to reach a selected required discharge pressure of different required discharge pressures selected in accordance with water amount information and a degree of contamination of the sensor.

Abstract: An embodiment according to the present invention is to provide a control method of a refrigerator that can operate a compressor before a start of a defrost operation and during a predetermined time to supply a high-temperature hot gas to an evaporator. With the control method of the refrigerator according to the embodiments of the refrigerator, the compressor is driven immediately before the defrost operation and the blower fan cooling the compressor stops, such that the high-temperature hot gas can be supplied to the evaporator, thereby increasing the defrost efficiency.

Abstract: A refrigerator is provided. The refrigerator includes a compressor, a condenser, an expansion valve, an evaporator, a bypass pipe, and a valve device. The condenser condenses refrigerant discharged from the compressor, and the expansion valve expands the refrigerant condensed in the condenser. The evaporator evaporates the refrigerant expanded in the expansion valve, and the bypass pipe allows the refrigerant discharged from the compressor to move toward an inlet of the evaporator. The valve device allows the refrigerant discharged from the compressor to selectively move toward the bypass pipe or the condenser. The valve device comprises an inlet, a first outlet, and a second outlet. The refrigerant discharged from the compressor flows into the inlet. The refrigerant is discharged toward the condenser through the first outlet, and is discharged toward the bypass pipe through the second outlet. The first outlet has a diameter larger than that of the second outlet.