Abstract: A housing for electronic equipment having a cooling air flow passage system of first and second parts. The first part receives incoming cooling air, the air flowing through the first part and then, at one location, flowing from the first part into and then along the second part of the system. At a second location, some of the cooling air is returned into the first part of the system, the remainder of the cooling air having been expelled from the housing. Because of the return of cooling air into the first part of the system, there is an accumulation of incoming and returned air to pass along the first part of the system and this accumulation is greater than the rate at which air is entering and is being expelled from the housing. As a result, the accumulation of air travels at an extremely high flow rate through the first part of the system so as to maximize the removal of heat from electronic components.

Abstract: A device for improving air flow around shelf-based circuit cards housed within a card cage is disclosed where at least one fan is located above a rear portion of the card cage to draw air from beneath a forward portion of the card cage. The device is generally rectangular, having a forward portion, a rear portion and two side portions. A plurality of spaced parallel flanges extend from one side portion to the other side portion. Each flange, in cross-section, has an inverted L-shape, with a vertical section and a horizontal section, the horizontal section extending from the vertical section towards the forward portion of the device. Preferably, the height of the vertical section is a least 1.2 times the width of the horizontal section and the distance between adjacent flanges is at least the height of the vertical section. Also, preferably, the device is shaped from a single piece of sheet metal.