Card cage having an air cooling system

A card cage comprising

• a housing defining an upper compartment and a lower compartment which are separated by a sheet member, wherein the upper compartment defines a chamber receiving a plurality of vertically disposed spaced apart parallel printed circuit cards having heat-developing electrical components;
• a plurality of openings in said sheet member, each opening defining an air inlet having a minimum cross-sectional area and communicating with a space between a respective pair of printed circuit cards, wherein each inlet is located adjacent to a first end of each of said respective pair of printed circuit cards;
• a plurality of plate members, each plate member being disposed in a respective air-inlet to limit the cross-sectional area of the respective air-inlet, the position of each plate member being adjustable to vary the cross-sectional area of a respective air-inlet, and wherein each plate member is integrally formed from said sheet member;
• at least one fan for blowing air into the lower compartment and through each said air-inlet into said chamber to flow across the printed circuit cards such that the air passes from the first end of each printed circuit card received in said chamber to a second end of each printed circuit card, said second end being opposite said first end, said fan being in fluid communication with each said air-inlet;
• and
• an outlet in said housing communicating with said chamber to exhaust air therefrom after passing over the printed circuit cards, said outlet being located adjacent to the second end of the printed circuit cards.