One key challenge in maintaining clean water supplies is the potential for backflow. A situation where water flows in the opposite direction within a plumbing system creates a contamination risk.

Backflow can occur due to changes in pressure or cross-connections with non-potable water sources, posing a serious threat to public health. Sprinkler backflow preventers play a crucial role in protecting water systems.

By understanding how it works, we can maintain the cleanliness of our water supply. Let’s check how sprinkler backflow preventer work:

Inlet Connection

Pressure Differential

When the irrigation system is turned on, water flows from the main supply into the backflow preventer. The pressure of the incoming water pushes against the primary check valve. It opens the backflow preventer and allows water to enter the irrigation system. Simultaneously, the pressure on the secondary check valve keeps it closed, preventing any water from flowing backwards.

Normal Operation

During normal operation, water flows through the open primary check valve and continues moving into the irrigation system. The primary check valve remains open due to the pressure differential the water supply creates. Meanwhile, the secondary check valve remains closed due to the opposing pressure from the irrigation system.

Backflow Event

A sudden drop in water pressure in the main supply line or a backflow event may occur. A few examples are a water main break or a drop in water pressure due to firefighting activities. In such a scenario, the pressure in the irrigation system may exceed the pressure in the main water supply. This pressure reversal would normally cause water to flow backwards, potentially contaminating the potable water.

Backflow Prevention

In backflow, the pressure reversal causes the primary check valve to close. It prevents backward water flow into the main supply line. Simultaneously, the pressure created in the irrigation system pushes against the closed primary check valve. It opens the secondary check valve. It will allow the excess pressure to be released into the atmosphere. As a result, it prevents contamination of the main water supply.