Patent ID: 6945071
Filing Date: 2005-09-20
Classification: B60H,F25D

Abstract:
1. A refrigeration unit for conditioning and circulating air in a trailer, said refrigeration unit including an evaporator fan located downstream of an evaporator and a microprocessor for controlling and recording conditions in said trailer, said refrigeration unit further including: said fan producing a suction pressure upstream thereof and a discharge pressure downstream thereof; two flow paths between the interior of said trailer and ambient atmosphere surrounding said trailer; a first one of said two flow paths is for supplying atmospheric air to air circulating in said trailer and extends from a point which is just upstream of said fan and which is at suction pressure and said ambient atmosphere whereby atmospheric air is supplied to circulating air; a second one of said two flow paths is for discharging circulating air from said trailer to said ambient atmosphere and extends to said ambient atmosphere from a point which is just downstream of said fan and which is at discharge pressure; valve means normally biased to a position preventing fluid communication between either of said two flow paths and said ambient atmosphere; and means for moving said valve means to a position permitting fluid communication between the interior of said trailer and said ambient atmosphere via both of said flow paths responsive to said microprocessor.