Abstract: The present invention is for use in measuring the amount of wear of a shroud disposed on the inner surface of a casing in a turbo machine. A sensor body enclosing a half mirror and defining a purge air intake port is mounted to a shroud disposed on the inner surface of a casing as opposed to the tip of rotor blades. A small conical hole is formed in the shroud at the end of the sensor body. The sensor body is connected to an electronics section, including a light-emitting circuit and an image processing circuit, by a light-transmitting fiber optic cable and a light-receiving multi-core fiber optic cable respectively. The electronics section calculates the amount of wear of the shroud from the amount of light reflected from the surface defining the conical hole, an opening in the end of which varies in size as the shroud wears. Therefore, the amount of wear of the shroud surface is measured without being influenced by variations in temperature and the measurement is thus highly precise.

Abstract: A hollow rotor blade of a gas turbine includes a shaped core accommodated within a hollow space formed between two skins and joined to the skins. The fatigue strength at a portion where the skins are joined to the core is enhanced. More specifically, the portions of the skins joined with the core are in the form of island-shaped protrusions, and the core is joined to these protrusions by solid-phase diffusion bonding, diffusion-brazing, liquid-phase diffusion bonding, and the like.

Abstract: A laser-optical apparatus for measuring blade tip clearance, e.g. of a compressor or gas turbine, uses a laser beam, fiber optics, a light probe and electrical circuits (14, 25) for processing data from the probe, and includes a light probe (16) having a lens (17) for making parallel a light beam from the optical fiber cable (15) for illumination, a half-mirror (18) for separating illuminating light and reflected light, a movable lens (19) for adjusting focus of the light beam on the object (12), an object lens (21), and a lens (22) for collected reflected light from half-mirror (18) and directing it to an entrance to the optical fiber cable (24) which transmits received light to the light reception circuit (25).