The question frequently arises regarding what occurs if there is a failure of the inner Element Well. The Element Well is a pressure containment component of the HTP/HTX. If it becomes broken, vessel gases are free to travel into the purge outlet vent cavity. If and when this occurs, the reactor gases will immediately begin to flow to the outlet vent port leading to the flowmeter/valve of the HFS. In Claus service, the exiting leaking gases will immediately be cooled as they pass to the outlet purge port and begin to precipitate into liquid/solid sulfur, which over a short time will clog the outlet purge port orifice as it flows towards the downstream flowmeter/needle valve assembly. Prior to the sulfur totally clogging the outlet port, this flow of sulfur gas remains limited to the low flow purge rate set by the flowmeter needle control valve located downstream of the outlet vent port. The proper flow rate is approximately 10 lph. Actually, if the Element Well has failed, this flow rate will be much lower than the set purge flow rate since the gas pressure is now equal to the lower operating pressure of the vessel, not the elevated purge pressure set at the regulator. If there is evidence of element well failure, manually close the needle valve on the flowmeter to stop the gas flow.