Abstract: A heat exchanger tube is constituted by a flat tube body 14 shaped like a plurality of cylindrical tubes arranged mutually proximally in a plane and connected together at mutually proximate portions of the tubes as communicating portions 13. Cylindrical portions 15 corresponding to the cylindrical tubes of the flat tube body 14 have inner peripheries formed with swirling-flow-forming protrusions 16 directed along spiral trajectories coaxial with central axes O of the cylindrical portions 15 so that the respective cylindrical portions 15 may have individual swirling flows of the exhaust gas 10.

Abstract: A cooling-water temperature is detected at startup of an engine. When the detected temperature falls below a set water-temperature, a water pump is stopped independently of a normal control on rotational frequency of the water pump depending on engine operational state. Calculated is a total heat amount required for raising the current water-temperature to the set water-temperature, and integrated is an heat amount lost by the cooling water from the engine from the startup. When an integrated value reaches the total heat amount, the water pump is operated for a required time to uniformize temperature distribution of the cooling water. Then, the cooling-water temperature is detected again. If the detected temperature is still below the set water-temperature, the same control is repeated; if the detected temperature is equal to or greater than the set water-temperature, the normal control is restored.

Abstract: A method for manufacturing a flat pipe 1 with concave-convex shapes on inner and outer surfaces includes making incisions with an expanded shape of the flat pipe 1 in a metal thin plate 2 such that intermediate portions 4 (middle portions) in the expanded shape of the flat pipe 1 widthwise of the expanded shape are left uncut from the thin plate 2, machining the concave-convex shapes in a range of the expanded shape of the flat pipe 1 and raising the expanded shape of the flat pipe 1 from the thin plate 2 as cut-and-raised pieces 8 with the uncut intermediate portions 4 in between, closing tips of the cut-and-raised pieces 8 together to form an overall shape of the flat pipe 2, and separating the uncut intermediate portions 4 from the thin plate 2 to obtain the flat pipe 1.

Abstract: A cooling-water temperature is detected at startup of an engine. When the detected temperature falls below a set water-temperature, a water pump is stopped independently of a normal control on rotational frequency of the water pump depending on engine operational state. Calculated is a total heat amount required for raising the current water-temperature to the set water-temperature, and integrated is an heat amount lost by the cooling water from the engine from the startup. When an integrated value reaches the total heat amount, the water pump is operated for a required time to uniformize temperature distribution of the cooling water. Then, the cooling-water temperature is detected again. If the detected temperature is still below the set water-temperature, the same control is repeated; if the detected temperature is equal to or greater than the set water-temperature, the normal control is restored.

Abstract: A method for manufacturing a flat pipe 1 with concave-convex shapes on inner and outer surfaces includes making incisions with an expanded shape of the flat pipe 1 in a metal thin plate 2 such that intermediate portions 4 (middle portions) in the expanded shape of the flat pipe 1 widthwise of the expanded shape are left uncut from the thin plate 2, machining the concave-convex shapes in a range of the expanded shape of the flat pipe 1 and raising the expanded shape of the flat pipe 1 from the thin plate 2 as cut-and-raised pieces 8 with the uncut intermediate portions 4 in between, closing tips of the cut-and-raised pieces 8 together to form an overall shape of the flat pipe 2, and separating the uncut intermediate portions 4 from the thin plate 2 to obtain the flat pipe 1.

Abstract: A heat exchanger tube is constituted by a flat tube body 14 shaped like a plurality of cylindrical tubes arranged mutually proximally in a plane and connected together at mutually proximate portions of the tubes as communicating portions 13. Cylindrical portions 15 corresponding to the cylindrical tubes of the flat tube body 14 have inner peripheries formed with swirling-flow-forming protrusions 16 directed along spiral trajectories coaxial with central axes O of the cylindrical portions 15 so that the respective cylindrical portions 15 may have individual swirling flows of the exhaust gas 10.

Abstract: An exhaust gas recirculation (EGR) cooler includes a plurality of tubes and a shell enclosing the tubes. During use, cooling water is supplied to and discharged from the shell, and exhaust gas is guided from a diesel engine into the tubes to be heat exchanged with the cooling water. An inner periphery of each of the tubes is formed with three streaks of spiral protrusions running without crossing and with phases peripherally shifted to each other. A pitch P ratio of each of the spiral protrusions to an inner diameter of each of the tubes is 2.0-4.0, and a ridge height H ratio of each of the spiral protrusions to the inner diameter of each of the tubes is 0.1-0.2.

Abstract: An EGR cooler is provided which is satisfactorily applicable to a diesel engine with no substantial lowering in performance. With respect to the EGR cooler which is provided with tubes 3 and a shell 1 enclosing the tubes 3, cooling water 9 being supplied to and discharged from the shell 1, exhaust gas 10 being guided from a diesel engine into the tubes 3 to be heat exchanged with the cooling water 9, an inner periphery of each of the tubes 3 is formed with three streaks of spiral protrusions 12, 13 and 14 running without crossing and with phases peripherally shifted to each other, a pitch P ratio (P/D) of each of the spiral protrusions 12, 13 and 14 to an inner diameter D of each of the tubes 3 being 2.0-4.0, a ridge height H ratio (H/D) of each of the spiral protrusions 12, 13 and 14 to the inner diameter D of each of the tubes 3 being 0.1-0.2.

Abstract: A pusher which pushes up semiconductor wafers has wafer fixing grooves to which they are fixed. Wafer detecting sensors which detect whether the semiconductor wafers are present are positioned in side walls of the wafer fixing grooves. The pusher is composed of an grounded aluminum base material and a resin coat formed on the base material. The surface of the aluminum base material is alumite-treated. The resin coat has a thickness of approximately 20 .mu.m. The resin coat is made of Teflon.