A flat heat exchanger plate typically used in a bulk material heat exchanger having an improved construction which increases heat transfer and service period by reducing bulk material accumulation. The flat heat exchanger plate is designed to operate under a negative internal pressure to eliminate depressions or dimples that are typically formed into the sides of these types of heat exchanger coils during the manufacture process. The dimples are created to reinforce the heat exchanger plate from positive internal pressures that other wise would cause the heat exchanger plate to bow due to internal positive pressures. With the removal of the depressions or dimples the tendency for bulk material to accumulate to the exterior surface of the plate is reduced, thereby increasing the service period of the plate and heat transfer. The flat heat exchanger plate tapers from wide to narrow along the direction of flow of bulk material across the plate to further reduce accumulation of bulk material.