When backflow conditions occur, the Flood-Gate closes automatically, providing positive shut-off and property protection.

A sewerage backflow into a building/house will result if a stoppage or similar problem in the municipal/street sewer or septic system occurs, causing the water level to rise above the top of the building/house drain. As the backflow occurs, the trapped air in the sewer line is forced into the expansion chamber through a port in the backflow valve. As the expansion chamber fills with air and expand, the knife gate rises until the 4" or 6" drainage opening is completely sealed off. Once complete closure is attained, all backflow is prevented from entering the structure.

Once the backflow subsides and the water level returns to normal, the air is forced out of the expansion chamber, allowing the knife gate to open, resetting the valve.

The Flood-Gate is designed to work in residential basements, commercial and institutional buildings, industrial applications, and restaurants.

Depending on individual circumstances, the Flood-Gate can be installed in a ventilated pit in the horizontal drain line between the building and the sewer main. although this provides complete protection from flooding, all of the plumbing fixtures in the building will be out of service once the valve is activated.

The valve could also be installed where the below grade (as in a basement) fixtures are connected on the upstream side of the valve, and the above grade fixtures connected on the downstream side. This allows continued use of the above grade connected fixtures, while protecting the below grade areas from flooding.

Each valve has been inspected and tested to a 45-ft. head, or 19.3 psi, without any signs of leakage or weepage. The valve conforms to ASME A112.14.1-1975 backwater valve requirements, has a certificate of compliance from CSA and is IAPMO listed. Jay R. Smith Mfg. Co.