Light table apparatus and methods for inspecting heat exchanger plates for defects using light

An inspection method for detecting fluid-transmitting defects in a heat exchanger plate, the method comprising:

• positioning a heat exchanger plate on top of a support frame of a light table apparatus, the support frame containing a plurality of illumination units configured to produce light energy, and the heat exchanger plate including peripheral portions surrounding a central portion;
• positioning a gasket-like template on top of the support frame of the light table apparatus before the step of positioning the heat exchanger plate, the gasket-like template including a light-transmissive base panel and a resilient light seal coupled to the base panel and facing upwardly away from the support frame, wherein the gasket-like template is configured to block light energy transmission around or through the peripheral portions of the heat exchanger plate;
• engaging the resilient light seal with contours defined along the peripheral portions of the heat exchanger plate as the heat exchanger plate is positioned on top of the support frame, such that the central portion and corrugations located on the central portion are circumferentially surrounded along one side of the heat exchanger plate that faces towards the gasket-like template and towards the support frame;
• darkening an ambient environment around the light table apparatus and operating one or more of the plurality of illumination units to produce light energy and thereby irradiate the one side of the central portion of the heat exchanger plate that faces towards the top of the support frame;
• visually inspecting an opposite side of the central portion of the heat exchanger plate while the ambient environment is darkened and the plurality of illumination units are operated, wherein light energy from the plurality of illumination units will escape through the central portion of the heat exchanger plate only through fluid-transmitting defects present in the central portion and thereby will illuminate such defects in a manner that enables accurate identification and location of any such defects in the heat exchanger plate.

A light table apparatus for detection of fluid-transmitting defects in a heat exchanger plate, the light table apparatus comprising:

• a support frame defining an enclosed space, the support frame including a bottom wall and sidewalls defined by a non-light-transmissive material and a top wall defined by a light-transmissive panel, the top wall being sized to receive an entirety of one or more heat exchanger plates laid manually by a user onto the light-transmissive panel so as to be tested for defects;
• a plurality of illumination units enclosed within the enclosed space of the support frame;
• a control mechanism for selectively operating one or more of the plurality of illumination units to irradiate light energy through the light-transmissive panel at the top wall;
• and
• at least one light shielding element positioned in engagement with the heat exchanger plate by the user when the heat exchanger plate is positioned onto the light-transmissive panel, the at least one light shielding element configured to block light energy transmission around or through peripheral portions of the heat exchanger plate such that light energy irradiated from the plurality of illumination units is directed to one side of a central portion of the heat exchanger plate, which faces towards the support frame,
• wherein when the heat exchanger plate and the at least one light shielding element are placed on top of the support frame, and the plurality of illumination units are activated to produce light energy, an environment surrounding the light table apparatus can be darkened and light energy will escape only through defects in the central portion of the heat exchanger plate such that a user visually inspecting an opposite side of the central portion of the heat exchanger plate, which faces away from the support frame, will be able to identify and locate any defects revealed by such transmission of light energy through the defects in the heat exchanger plate.