Heat preservation device

The utility model relates to a heat preservation device which comprises a constant-temperature box, the constant-temperature box comprises a box body, a box cover covering the opening end of the box body and a heat conduction block arranged in the box body, a plurality of containing holes are formed in the end, facing the opening end, of the heat conduction block, the containing holes extend alonga straight line, and injectors are inserted into the containing holes. The heat preservation device is arranged; the heat conduction block is arranged in the box body; the end, provided with the containing hole, of the heat conduction block faces the open end of the box body, a plurality of injectors with reagents pumped at the beginning can be placed in the containing hole, the heat conduction efficiency of the heat conduction block is larger than that of air, the heat conduction block placed in the constant-temperature box occupies most of the internal space, and therefore the exchange efficiency of air in the cons