Ultra low temperature split door freezer

An upright freezer comprising:

• a freezer chamber contained by insulated peripheral walls including a pair of side walls, a top wall, a bottom wall and a rear wall, the front edges of said top wall, bottom wall and side walls including resilient three-bulb gaskets;
• an insulated mullion extending across a front opening of said chamber and mounted between said pair of side walls, said mullion including a pair of upper and lower two-bulb gaskets attached on an outside surface thereof;
• a self-regulating heating strip extending generally along an outside surface of said mullion between said pair of upper and lower two-bulb gaskets;
• an upper insulated door and a lower insulated door hingedly secured to one of said side walls and, in closed positions, said upper door sealing against the three-bulb gaskets of said pair of side walls and said top wall and against the upper two-bulb gasket of said mullion, said lower door sealing against the three-bulb gaskets of said pair of side walls and said bottom wall and against the lower two-bulb gasket of said mullion;
• and
• a refrigeration unit connected to said freezer which cools said chamber to a substantially uniform temperature.

An upright, ultra low temperature freezer comprising:

• a freezer chamber contained by insulated peripheral walls including a pair of side walls, a top wall, a bottom wall and a rear wall;
• a mullion extending horizontally across a front opening of said chamber and mounted between said pair of side walls;
• an upper door and a lower door hingedly secured to one of said side walls and having respective lower and upper edges thereof sealing against said mullion when in closed positions;
• and,
• a refrigeration unit connected to said freezer and including evaporator coils contained within peripheral walls of said chamber which cool said chamber to a substantially uniform temperature below about -50.degree. C. to -90.degree. C.