Abstract: A control system for an in-line, ultra-pure deionized water (UPDI) heater including a housing, at least one fluid pathway through the housing, and a resistive heating element proximate the fluid pathway for heating an operating fluid flowing through the pathway. The control system includes a mechanism for determining an actual power value which is indicative of the power being applied to the resistive heating element, a mechanism for determining a needed power value which is indicative of the power required to achieve an outlet fluid temperature substantially equal to a user-selectable preset fluid temperature, a mechanism for adjusting the actual power applied to the resistive heating element based on an offset between the actual power value and the needed power value, and a mechanism for overriding the adjusting mechanism when the offset is greater than a predetermined level.

Abstract: A new and improved end-cap for use with a fluid heater is disclosed. The end-cap includes an end wall, a first groove in the end wall for receiving a first tube, a second groove in the end wall located radially inward of the first groove for receiving a second tube, and a third groove in the end wall located radially inward of the second groove for receiving a third tube. A first side wall separates the first and the second grooves, and a second side wall separates the second and the third grooves. The first and the second side walls each are relatively thin which facilitates deformation in a radial direction in response to differential thermal expansion of the end cap in relation to the tubes. In addition, the side walls compress in a circumferential direction in response to differential thermal expansion of the end cap in relation to the tubes. An annular flange is positioned radially inward of the second side wall to facilitate centering the third tube in the third groove.

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.

Abstract: An immersion heater for corrosive fluids includes an electrically resistive material strand operative upon connection to a source of power to provide heat. A thermally conductive electrically insulating fill material is disposed around the electrically resistive material strand. An electrically conductive sheath encases the fill material. A tubular jacket of a flexible chemically inert material encases the electrically conductive sheath. A fluid flow passage is defined between the tubular jacket and the sheath for allowing a fluid to flow therethrough. The fluid is a purge gas that flows between the sheath and the jacket in order to remove any corrosive fluid which may have penetrated the jacket. A method for manufacturing an immersion heater is also disclosed.