Gas-based bridge crane lifting rope detection device

The invention discloses a gas-based bridge crane lifting rope detection device. A bridge crane comprises a lifting rope, a trolley fixedly connected with one end of the lifting rope and a lifting appliance fixedly connected with the other end of the lifting rope. The detection device comprises a swing angle detection unit, a rope length detection unit and a signal processing unit, wherein the swing angle detection unit is arranged at the end, close to the lifting appliance, of the trolley, and the lifting rope penetrates through the swing angle detection unit, and is connected with the lifting appliance; the swing angle detection unit is filled with gas so that a corresponding gas volume concentration and corresponding gas pressure can be acquired when the lifting rope swings; the rope length detection unit is arranged at the end, close to the trolley, of the lifting appliance, is connected with the swing angle detection unit, and is used for acquiring gas diffusion time corresponding to the length of the lif