摘要 |
A transport refrigeration system of the type which holds a set point temperature via heating and cooling cycles. The system includes a refrigerant circuit which includes a compressor, condenser, receiver, evaporator, and a mode selection means for selectively directing hot compressed refrigerant gas to the condenser, or, through a hot gas conduit to the evaporator. The system includes a prime mover, typically a diesel engine for driving the compressor. The system includes a first hot gas flow control means having a predetermined, limited, refrigerant flow capability for controlling the flow of refrigerant therethrough. It further includes a second hot gas flow means having a refrigerant flow capability which is substantially greater than the predetermined limited refrigerant flow capability of the first hot gas flow control means. The first and second hot gas flow control means are disposed in parallel fluid flow relationship in the hot gas conduit. Each of the hot gas flow control means is selectively operable to an open or closed condition. The hot gas flow control means may be opened or closed in any desired combination to achieve a desired hot gas flow rate through the hot gas line. In the preferred embodiment the predetermined limited refrigerant flow capability of the first hot gas flow control means is sufficiently small so that it will limit the suction pressure rise of the compressor to a level which will not overload the internal combustion engine.
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