The invention discloses a low-resistance
backflow preventer, and relates to the technical field of
backflow preventers, the low-resistance
backflow preventer comprises a main valve body, two elastic sealing check valves and a hydraulic differential type
water escape valve, a sliding seat is slidably sleeved outside a valve rod between a
valve seat and a valve plate, and an annular sealing air bag
cushion is sleeved outside the sliding seat; a first spring is arranged between the sliding seat and the valve plate, a buffering
assembly is arranged between the sliding seat and the
valve seat, a plurality of water guide pipes are arranged between the
water storage device and the sliding seat, an air guide
pipe is arranged between the air inflation device and the sliding seat, the sealing air bag
cushion is communicated with the air guide
pipe through a mounting ring and the sliding seat, and annular protrusions are arranged on the inner surface of the first groove and the inner surface of the second groove. According to the elastic sealing
check valve, the situation that impurities are clamped into the two sides of the sealing air bag
cushion in the closing process of the elastic sealing
check valve can be prevented, the sealing performance of the elastic sealing
check valve can be effectively improved, liquid back seepage caused by poor sealing is prevented, and the purpose of automatically cleaning the impurities attached to the sealing air bag cushion can be achieved.