Evaporation closed chamber for detecting hazardous substance

An evaporation closed chamber for detecting a hazardous substance, comprising a closed chamber (1) and an intake device (2), wherein the intake device (2) is communicated with the interior of the closed chamber (1), the closed chamber (1) is connected with an exhaust pipe (3), and sampling openings (4) are opened in the closed chamber (1);

• wherein the closed chamber (1) is provided with a gas compensation device (5) configured for performing gas volume compensation on the interior of the closed chamber (1) in a gas sampling process, the gas compensation device (5) is arranged on one or more surfaces of the closed chamber (1), the gas compensation device (5) comprises an orifice plate (6), a pressure plate (7), a drive device (8) and an elastic film (9), the orifice plate (6) is mounted on any surface or multiple surfaces of the closed chamber (1), the elastic film (9) is arranged on an outer side face of the corresponding orifice plate (6), the pressure plate (7) is arranged on an outer side face of the corresponding elastic film (9), and the drive device (8) is in transmission connection with the corresponding pressure plate (7) so as to drive the pressure plate (7) to move forwards and backwards to press the elastic film (9) to be in contact with the orifice plate (6), the intake device (2) comprises a first fan or pump (16), a filter (17) and a valve (18), and the first fan or pump (16), the filter (17) and the valve (18) are communicated with the interior of the closed chamber (1).