High temperature resistant seal is a critical functional component for ISG vertical pipeline centrifugal pumps operating with hot media, as it creates a reliable barrier between the pressurized process fluid and the external environment. Its performance directly prevents medium leakage, protects rotating shaft surfaces, and maintains stable pump operation even when fluid temperatures far exceed the limits of standard sealing configurations.

‌Thermal stability of seal face material pairs‌
The core friction pair of the high temperature resistant seal is engineered with material formulations that retain stable physical properties and consistent flatness even under prolonged exposure to elevated medium temperatures. These materials resist thermal softening, thermal deformation, and surface hardness drop that would otherwise break the critical flat seal face clearance and cause excessive leakage or accelerated wear. The selected face materials also maintain excellent self-lubricating properties at high operating temperatures, preventing direct dry metal-to-metal contact even when the liquid lubrication film between the two faces becomes thinner under high heat conditions. This design avoids sudden seal face failure that often occurs when standard seals are exposed to sustained high temperature working cycles.

‌High temperature compatible auxiliary sealing elements‌
All secondary sealing components, including O-rings, gaskets, and flexible sealing rings, are made from elastomer or special polymer materials formulated to resist thermal aging, permanent compression set, and chemical degradation in high temperature medium environments. These materials do not harden, crack, or lose their elastic recovery capability after long-term immersion in hot water or hot process fluid, maintaining consistent preload on the seal faces and static sealing points across thousands of operating hours. The geometric cross-section of these auxiliary elements is optimized to accommodate minor thermal expansion differences between metal components and sealing parts, preventing local over-compression or insufficient sealing force as system temperature rises from ambient to peak operating levels. This eliminates the common failure mode where standard elastomer seals lose elasticity and develop hidden leakage paths after repeated heat-up and cool-down cycles.

‌Heat dissipation and thermal isolation structure around the seal chamber‌
The seal assembly is integrated with a dedicated thermal isolation and heat dissipation structure that blocks excessive heat transfer from the high temperature process medium to the seal faces and auxiliary components. A circulating cooling flow path can be connected to the seal chamber to carry away frictional heat generated at the seal faces and reduce the overall operating temperature of all sealing elements, creating a stable thermal environment far below the maximum temperature of the conveyed medium. This structure also prevents localized hot spots near the seal faces that could cause vaporization of the liquid lubrication film, which would otherwise lead to severe dry friction and rapid seal failure. Even when the pump operates continuously at maximum allowable medium temperature, this thermal management system keeps the seal assembly running within its safe, stable temperature range.

‌Compensation design for thermal expansion of rotating and stationary parts‌
The entire high temperature resistant seal assembly includes built-in compensation mechanisms that accommodate differential thermal expansion between the rotating shaft, pump casing, and seal components. The spring loading mechanism maintains consistent, designed axial preload on the seal faces even when the shaft elongates thermally as temperature rises, ensuring the two friction faces remain in proper close contact without excessive gap or over-compression. All relative moving parts inside the seal assembly are designed with carefully calculated thermal clearances, preventing jamming, binding, or unexpected friction that could occur when different materials expand at different rates under high temperature conditions. This compensation design ensures the sealing system maintains stable dynamic performance through repeated thermal cycles from cold standby to full temperature continuous operation.