Abstract: An exhaust gas latent-heat recovery device includes: a heat transfer tube disposed inside a duct through which exhaust gas flows, the heat transfer tube having a water supply inlet into which water to be heated for recovering latent heat of the exhaust gas is supplied and a water supply outlet through which the water to be heated is discharged; and a water supply control part configured to control supply of the water to be heated to the water supply inlet. The water supply control part is configured to control supply of the water to be heated from the water supply inlet so that an outlet temperature being a temperature of the water to be heated at the water supply outlet is at a set temperature.

Abstract: An exhaust gas latent-heat recovery device includes: a heat transfer tube disposed inside a duct through which exhaust gas flows, the heat transfer tube having a water supply inlet into which water to be heated for recovering latent heat of the exhaust gas is supplied and a water supply outlet through which the water to be heated is discharged; and a water supply control part configured to control supply of the water to be heated to the water supply inlet. The water supply control part is configured to control supply of the water to be heated from the water supply inlet so that an outlet temperature being a temperature of the water to be heated at the water supply outlet is at a set temperature.

Abstract: A cutting head having a tapered shaft portion, a helical flute, and a flat shoulder surface is fastened to a shank having a front end surface, a tapered hole, and a helical flute through a fastening attachment in the form of a helical coil. The fastening attachment has a sectional shape substantially analogous in shape to a space defined between the helical flutes. The fastening attachment is fitted in one of the helical flutes, and is threaded into the other of the helical flutes until the shoulder surface is brought into close contact with the front end surface of the shank, and the outer peripheral surface of the tapered shaft portion is brought into close contact with the inner surface of the tapered hole, thus fastening the cutting head to the shank.