Abstract: In a mah jong game apparatus for a single player, a predetermined number of tiles randomly selected from a plurality of tiles are supplied to only the single player, and the player completes a hand by combining own tiles while exchanging the supplied tiles and an arbitrary tile in a randomly supplied tile, thereby going out. Thus, the player can enjoy the game while concentrating on making hands independently.

Abstract: The present invention proposes a heat pipe heat exchanger comprising a hot gas flow duct, a cold gas flow duct and a plurality of heat pipes each with spiral fins around thereof that are installed horizontally a little slanted so that an end of each heat pipe in said hot gas flow duct becomes a little lower than the other end, and that said spiral fins are winding clockwise around some of the heat pipes and counter-clockwise around some other heat pipes. This device can prevent a bias flow of the steel balls at the so-called shot cleaning process performed for elimination of dust deposited on the heat pipes by arranging a layout of the two kinds of heat pipes, namely the heat pipes with clockwise winding fins around thereof and the heat pipes with counter-clockwise winding fins, and if required, can even control the flow of the steel balls so that they gather onto the area where more dust is deposited.