Perforated Plate Scallop

Johnson Screens^® perforated plate scallops are an economical approach for retaining catalyst and protecting against catalyst leakage in a radial flow unit. The perforated scallops are light weight and easy to install in your reforming unit.

Scallops are installed as a partner to a centerpipe in a reformer. As thermal expansion and contraction of the vessel occurs, loads are exerted on the surfaces of the scallops and centerpipe. Perforated scallops are designed to deform under extreme load, acting as a safety valve to protect the centerpipe and reduce the chance for catalyst leakage into heaters or exchangers. Proper functioning as a safety device requires the scallop to be fabricated to specific tolerances and uniform shape. Johnson Screens scallops meet all these requirements.

 

Each licensor of radial flow units has critical perforation size specifications and characteristic end assembly details. Scallops are typically fabricated from 18 ga. (1.2 mm) sheet in 321H SS material and custom built for your particular unit's needs. Scallops fabricated from 16 ga. (1.57 mm) sheet are available for operators looking for a more rugged design. Johnson Screens is fully qualified for all licensors' scallop specifications.

 

Material in 321H SS is maintained in inventory to allow emergency replacement of components damaged during operation. Our field service crews are also available maintain your perforated scallops to quickly get your unit back on line.