Nut for use in fire protection device for ventilation duct has outer ring made of heat-resistant material. bonded to inner ring made of material which melts at high temperature

摘要

The nut has an outer ring (10) made of heat-resistant material. This is bonded to an inner ring (11) made of material which melts at high temperature and which has an internal thread (12). An Independent claim is included for a fire protection device for a ventilation duct comprising a spring-loaded bolt and a nut as described above.