Van-stone flanges

Lap-joint flanges are sometimes known as Van-stone flanges . 

A Van Stone flange is formed on the ends of the process tube. 

The inner surface of the Van Stone flange forms a gas seal with the end of the gunbarrel while the outer end, with a gasket, forms a water seal with the nozzle. Thus, as the process tube expands due to heating, the gunbarrel moves relative to the shield. If tubes arc replaced relatively frequently, the gunbarrel setting balance between expansion and contraction can be readjusted. 

Van Stone or welded flanges, corrugated steel gaskets... 

For purposes of this chapter, the process tube assembly starts with the inlet connector and ends with the outlet connector. It includes the connectors, nozzles, caps, plugs, process tube, gunbarrels, thermal shield blocks, donuts, gas seals, temperature detectors, orifices or venturis. Van Stone gaskets and gunbarrel flanges, plus miscellaneous bolts. The functions of this assembly are to 1) support the fuel, 2) channel the coolant, 3) seal the reactor atmosphere, 4) facilitate charge-discharge and 5) serve as a channel for control splines. 

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