Abstract: An apparatus for heating a fluid such as ultra-pure de-ionized (UPDI) water is disclosed. The fluid heater includes an intermediate body portion, a bottom end cap assembly secured to one end of the intermediate body portion, and a top end cap assembly secured to the other end of the intermediate body portion. The intermediate body portion includes a number of concentric quartz tubes wherein a first quartz tube is spaced radially inwardly of a second quartz tube to define an inner fluid pathway for heating UPDI water while flowing through the inner fluid pathway. A third quartz tube is spaced radially outwardly of the second quartz tube and radially inwardly of a fourth quartz tube to define an outer annular fluid pathway for further heating the UPDI water received from the inner fluid pathway. A resistive heating element is interposed between the second and third quartz tubes for heating the UPDI water by means of conduction, convection and heat radiation with a heating efficiency approaching 100%.

Abstract: A purge manifold assembly, which can be used in a gas purged immersion heater, includes a housing having a vessel wall having an aperture extending therethrough. A purge manifold is located adjacent the vessel wall. The purge manifold includes an aperture extending therethrough and colinear with the vessel wall aperture, a bore extending in the purge manifold, in a direction approximately normal to the purge manifold aperture, and a port communicating the bore with the purge manifold aperture. A fitting body extends into the vessel wall aperture and the purge manifold aperture. The fitting body includes a longitudinally extending through bore and a port communicating with the through bore. The port also communicates with the port of the purge manifold. In this way, a purge gas is allowed to flow through a sheath enclosing a heater wire held in the housing of the gas purged immersion heater.