Mixer used for ventilation air methane and drawing-out methane and having automatic concentration control function

[0017] The present invention will be described with reference to the drawings and specific embodiments:

[0018] Such as figure 1 , figure 2 As shown, an exhaust air and exhaust gas mixer with automatic concentration control function, the mixer has a cylindrical shell 1; the two ends of the shell 1 are the exhaust air inlet end 10 and The mixed gas outlet end 11; the exhaust air inlet end 10 and the mixed gas outlet end 11 are provided with flanges and connected with corresponding pipes; the outer circumferential surface of the shell 1 has a plurality of exhausted gas uniformly distributed along the circumference Inlet pipe 12; the axis of the suction gas inlet pipe 12 is perpendicular to the axis of the casing 1; the number of the suction gas inlet pipes is 2-3 to ensure that the exhaust gas can evenly enter the mixer; The exhaust air inlet end 10 of the casing 1 is provided with a transition pipe with a tapered diameter. The transition pipe and the casing are connected by casting or welding. The end surface of the transition pipe is located near the exhaust air inlet end of the exhaust gas inlet pipe axis. One side; the outer side of the mixed gas outlet end 11 of the shell 1 is provided with a stepping motor mounting support, which is connected with the shell by casting or welding; the shell 1 is also provided with an inner edge Spool 3 with axis movement; combined Figure 4 , Figure 5 , The valve core 3 has a cylindrical structure, the inner diameter of the valve core 3 is the same as the inner diameter of the transition pipe, and the outer surface of the valve core 3 has a plurality of protruding guide rails 14 on the inner wall of the housing 1 There is a guide groove that matches with the guide rail on the outer surface of the valve core; there is an air inlet gap between one end surface of the valve core 3 and one end surface of the transition pipe near the exhaust air inlet end for draining gas into the mixer , And the other end of the valve core 3 is fixedly connected with the driving mechanism that drives its action; combined image 3 , The driving mechanism includes a transmission screw 5, a transmission wheel 6, a driving wheel 7 and a stepping motor 9; the stepping motor 9 is fixed on the mounting support outside the mixed gas outlet end, and the axis of the stepping motor 9 Depending on the form of the intermediate transmission, it can be arranged parallel or perpendicular to the axis of the housing 1; one end of the transmission screw 5 is threadedly fitted with the valve core 3, and the other end is fixedly connected to the transmission wheel 6. The driving wheel 7 and the stepping motor 9 are connected by a coupling 8, and the driving wheel 7 and the driving wheel 6 are connected by gear matching or a transmission belt; the driving wheel 6 is connected to the driving wheel at the output end of the stepping motor. The wheel 7 cooperates to drive the transmission screw 5 to rotate, thereby driving the valve core 3 to move along the axis of the casing in the housing 1, adjust the gap between the valve core 3 and the transition pipe, and further adjust the gas drainage Enter the gap of the mixer to achieve the purpose of adjusting the concentration of the mixer; the mixer is also provided with an air flow valve body 2 for adjusting the flow rate of the mixed gas of exhaust air and exhaust gas entering the shell; the air flow valve body 2 One end is fixed in the transition pipe by a bracket, the other end passes through the transition pipe, and the gap between the transition pipe and the valve core is located in the valve core 3; the air flow valve body 2 is formed by one side of the transition pipe Hollow drop shape with a diameter tapering to the spool side.

[0019] The outlet end of the mixed gas is connected with the outlet pipe of the mixer; a gas concentration sensor is arranged on the outlet pipe of the mixer.

[0020] The method of closed-loop control of the mixed gas concentration by the above-mentioned exhaust air and exhaust gas mixer: the gas concentration sensor set on the mixed gas outlet pipe sends the collected concentration signal to the controller, and the controller sends the collected concentration signal and setting The mixed gas concentration signal is compared, and then the control signal is output to the stepping motor. The stepping motor drives the driving wheel to realize forward and reverse rotation according to the control signal, so as to adjust the size of the exhaust gas inlet gap, thereby controlling the amount of exhaust gas entering the mixer Size; real-time measurement of mixed gas methane concentration signal to achieve closed-loop control of mixed gas concentration.