专利名称：Air-to-air heat pump 发明人：Allen Trask
申请号：US07/137164
申请日：19871223
性比赛
公开号：US04843838A
公开日：
19890704
专利内容由知识产权出版社提供
520和521
摘要：An air-to-air heat pump with improved efficiency of operation, and simplicity and economy of construction. Initiation and termination of defrost cycles during heating mode operation is controlled, in addition to the conventional clock timer, by a dual pressure switch responsive to pressure in the outdoor coil, thereby significantly reducing the length of defrost cycles with corresponding improvement in operating efficiency. The direction of refrigerant flow between the indoor and outdoor coils is established in a first line through the compressor by an electrically operated reversing valve, and alternatively through cond and third lines, depending upon whether the system is operating in the heating or cooling mode, by ries-connected check and float valves in each of such lines. When heating mode operation is resumed following a defrost cycle, the float valve has delivered all liquid-refrigerant to the indoor coil. Since there is no liquid refrigerant in the outdoor coil to be drawn into the compressor under the conditions, the usual trap type accumulator is not required and is therefore eliminated in the prent system.
双减政策申请人：TRASK; ALLEN
代理人：Charles S. McGuire洪升
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