Slovenia City Uses Duckbill Check Valve for Backflow Prevention

Backflow, the undesirable reversal of flow in a pipeline system, was a problem plaguing the city of Zalec in Slovenia. This was a long-term ordeal that presented itself along the Savinja River and prompted the city to take action.

In early 2013, the city of Zalec approached Nivo Eko, d.o.o. Co. to help solve this problem. The company’s engineering director made it his mission to study and purchase a variety of backflow preventers, in particular, check valves. After much time and money spent, he decided the best choice for Zalec would be a duckbill-style check valve due to its long life and maintenance-free design. Once this decision was made, five check valves were purchased from various companies located in North America and China.

The valves then needed to be tested. Nivo Eko designed and manufactured a testing apparatus that allowed each valve to be tested under flow conditions, head pressure and continual back pressure. This testing was necessary because the valves installed in Zalec would be subject to each of these conditions. After many hours of testing each check valve for both functionality and durability, the ProFlex duckbill check valve manufactured by Proco Products Inc. of Stockton, Calif., was selected.

Proco designs and supplies rubber expansion joints, penetration seals and duckbill check valves. Since the start of this project, it has supplied Nivo Eko with more than 150 check valves ranging in size from 6 to 78 in. These valves have been installed in Zalec and other municipalities across Europe to combat backflow issues.