The shaft seal heater is a device that recovers steam leakage from the shaft seal and uses its heat to heat the condensed water, reducing energy loss and improving the thermal efficiency of the unit. When steam turbines adopt an internal leakage type shaft seal system, a shaft seal heater (shaft seal cooler) is generally installed to heat condensate or desalinated water, recover shaft seal steam leakage, reduce shaft seal steam leakage and heat loss, and improve the environmental conditions of t