Since the process fluid does not touch the flange, selection of the back-up flange is based upon:
¤ Operating Pressure/Temperature
¤ External Corrosion
¤ Economy

Unique back-up rings are computer designed with a configuration engineered for maximum performance. The combination of hubs and back-up flange rings represent the most innovative two piece (Van Stone) style flange available today.

¤ Ductile Iron
¤ Dimensions are given in inches.
¤ Prime Painted or Hot Dipped Galvanized.
¤ O.D. and drilling are 150# class.
¤ Sizes larger than 36" available on request.
¤ Stainless Steel available on request.

Types of Back-Up Flanges are