Gas replacement chamber and roller kiln

The utility model discloses a gas replacement chamber which comprises a replacement chamber shell and a heat exchanger. An inlet of a gas transmission channel in the heat exchanger communicates with a gas source, and an outlet is provided with a main pipe; the main pipe is used for conveying gas into the replacement chamber shell from the bottom; the heat exchanger is used for cooling gas in the gas transmission channel to a preset value. In the gas replacement chamber, the heat exchanger cools the gas input into the replacement chamber shell to the preset value, so that the density of the gas is larger than that of original gas in the replacement chamber shell, the specific gravity difference of the gas and the original gas is obvious, and the original gas in the gas replacement chamber automatically flows to the upper space and is discharged; compared with the mode of replacing original indoor gas with input diluted gas in the prior art, the ventilation effect is better, the ventilation efficiency can be im