Ductile Iron Backflow Preventer DF41X-16Q

Product Description

A backflow preventer is a hydraulic control assembly that strictly limits water flow in a pipeline to unidirectional flow. Its function is to prevent the backflow of the medium in the pipeline under any operating conditions, thereby preventing backflow contamination.

Product Features

How the backflow preventer works: As the medium flows through the inlet check valve, the pressure is reduced due to mechanical resistance and head loss from flow, causing the inlet pressure to exceed the pressure in the relief valve chamber. The pressure above the relief valve diaphragm is equal to the inlet pressure. The pressure above the diaphragm exceeds the pressure in the relief valve chamber and the spring-loaded resistance, keeping the relief valve closed and allowing the medium to flow normally. When the pressure difference between the inlet and the relief valve chamber is less than 0.02 MPa, the medium reaches a critical state for backflow, at which point the pressure above the relief valve diaphragm is less than the combined pressure of the relief valve chamber and the spring-loaded spring. The relief valve automatically opens, expelling the backflowing medium out of the pipe. Simultaneously, a large volume of air enters the valve chamber, forming an air barrier that prevents backflow of the medium. When the pressure difference exceeds 0.02 MPa, the relief valve automatically closes.

Product Specifications

Product Size Guide