The Hallite 652 is a high pressure rod seal designed specifically for longwall mining applications. The seal design comprises three elements; an O ring energiser*, a polyurethane shell and a polyacetal anti-extrusion ring.The shell is manufactured in Hythane 181 to provide flexibilty for installation and responsiveness to the sealing lip. The rubber energiser ensures complete lip actuation under all pressure conditions and cushions the seal against shock loadings. The anti-extrusion ring enables the seal to withstand side loads and extreme pressure peaks during operation, even with the extrusion gaps which are the result of using remote plastic bearing strips such as Hallite 506.*In some cases a profiled energiser (as T621) is used.