At Poly Processing, we’re are often asked how do we bottom discharge a double wall polyethylene tank, our SAFE-Tank®, and still maintain the integrity of the containment. We’ve developed a unique bellows transition fitting, which allows for flooded suction to a pump or head pressure build-up to bottom-discharge while maintaining containment integrity.
Our primary tank connections contain an inner wall flange with an expansion joint, which allows for volume and temperature variances that cause the polyethylene tank to expand and contract. Additionally, we have a bellows transition fitting that slides over the fitting connection and onto the outer wall of the tank. The bulkhead and gasket maintain the integrity of the transition fitting at the bottom outlet of the safe tank. Customers also wanted the ability to extend the containment beyond the fitting itself. We designed our bellows transition fitting to have an ANSI bolt hole pattern which accommodates a six-inch flange and extends the containment beyond the tank. You’re still going to have your primary line, your feed line, and now you can add a flange on the outer, extended double wall pipe. Containment is only limited by how far you want it to go.