Device for preventing suck-back during cleaning of filling machine

The utility model discloses a device for preventing cleaning suck-back of a filling machine, which comprises the filling machine, an overflow port of the filling machine is connected with an overflow pipe, the end portion of the overflow pipe is open, the outer side of the upper end of the overflow pipe is sleeved with an overflow cap, the upper portion of the overflow pipe is provided with a vent hole, and the vent hole is communicated with the overflow pipe. A boss is arranged at the position, close to the vent hole, of the overflow pipe and located between the outer wall of the overflow pipe and the inner wall of the overflow cap. The self-made overflow pipeline and the overflow ventilation cap are installed to balance the pressure in the system and the pressure outside the system after the filling machine is cleaned, the problem of negative pressure suck-back is avoided, the vent holes are formed in the overflow pipe, the pipeline ventilation effect is achieved, and the problem that foreign matter returns