Abstract: A fire and corrosion resistant enameled exteriorly sealing valve which may be mounted to a nozzle of a reaction vessel, comprising: a valve housing (1) having a valve opening therein, said housing being both internally enameled and enameled at said opening; a valve shaft (3) comprising a valve head (4) proximate one end thereof, said shaft and valve head being enameled on its outer surface; said valve head having a ground seat surface (4a) for mating with a housing seat surface (2a) at said opening provided at an extension (2, 21) of the valve housing (1); a stuffing box for the valve shaft (3), containing a packing (6, 7) out of material resistant to high temperatures; a spring package (17) engaging the valve shaft (3) and biasing the valve head (4) in a closed position, and by which a sufficiently high sealing force is provided between the two ground seat surfaces (2a, 4a) to maintain a seal in the presence of a fire; and said valve further comprising an actuation device (16) for opening and closing the val