Cylinders used to open the master switch, and then clockwise rotating low pressure regulator screw table to compress the main spring and transmission film, pad, and push-rod spring open the trap door.

• 使用时先打开钢瓶总开关，然后顺时针转动低压表压力调节螺杆，使其压缩主弹簧并传动薄膜、弹簧垫块和顶杆而将活门打开。