Abstract: A heating coil includes a plurality of loop portions disposed coaxially along an axis, a first lead portion and a second lead portion which electrically connect to a power source, and a connection portion which connects the plurality of loop portions, the first lead portion, and the second lead portion in series.

Abstract: A heating apparatus and a heating method are provided. The heating apparatus includes a coil configured to receive AC power to form a magnetic field that inductively heats a workpiece, a spray unit configured to spray cooling fluid including a liquid to the coil in a form of mist at least during a period in which the AC power is supplied to the coil. Alternatively, the spray unit may be configured to spray the cooling fluid in the form of mist to a heating target portion of the workpiece placed in the magnetic field at least during the period in which the AC power is supplied to the coil.

Abstract: A heating apparatus and a heating method are provided. The heating apparatus includes a coil configured to receive AC power to form a magnetic field that inductively heats a workpiece, a spray unit configured to spray cooling fluid including a liquid to the coil in a form of mist at least during a period in which the AC power is supplied to the coil. Alternatively, the spray unit may be configured to spray the cooling fluid in the form of mist to a heating target portion of the workpiece placed in the magnetic field at least during the period in which the AC power is supplied to the coil.

Abstract: A heating coil is configured to inductively heat an inner surface of a tubular workpiece. The heating coil includes a head portion configured to be inserted into the workpiece and to inductively heat the inner surface of the workpiece, and a pair of lead portions connected to one end of the head portion and the other end of the head portion respectively. The head portion and the lead portions are configured as pipe members forming a series of flow channels through which coolant flows. A cross-sectional area of the flow channel inside each of the lead portion is greater than a cross-sectional area of the flow channel inside the head portion.

Abstract: An induction heating coil (3) has a primary coil (4) to which electric power is supplied and a ring-shaped secondary coil (5) forming a closed circuit. The primary coil (4) has a base-side portion that covers an outer periphery of the secondary coil (5) and a distal-side portion extending from the base-side portion in the center axis direction of the secondary coil (5) in a state in which the base-side portion covers the secondary coil (5). The opening width of the base-side portion is greater than the opening width of the distal-side portion. The secondary coil (5) is provided such that it can be inserted into and removed from the inside of the primary coil (4) from the base-side portion of the primary coil (4).