Seal removal jig, seal removal method, and seal portion

A seal removal jig used for removing a seal portion from a casing of a rotary machine, the seal removal jig comprising:

• a jig body configured to be pushed up from below in a vertical direction by a jack;
• and
• a jig fixing portion configured to detachably fix the jig body to the seal portion,
• wherein the casing includes a casing inside surface configured to internally accommodate an impeller rotatable about an axis, the casing inside surface opposing an outside surface of the impeller in a radial direction with respect to the axis,
• the seal portion is disposed on the casing inside surface, and is configured to seal a gap with the impeller by opposing the outside surface of the impeller from an outer side in the radial direction,
• the casing further includes
• an upper half forming an upper part in the vertical direction with respect to the axis and having a cross section perpendicular to the axis formed in a semicircular arc shape, and
• a lower half forming a lower part in the vertical direction with respect to the axis and having a cross section perpendicular to the axis formed in a semicircular arc shape,
• the seal portion includes
• an upper half seal portion configured to be attached to the upper half, and
• a lower half seal portion configured to be attached to the lower half,
• the jig body includes
• a jig contact portion configured to come into contact with an end surface of the upper half seal portion or the lower half seal portion in a circumferential direction about the axis, and
• a jig protrusion protruding outward in the radial direction with respect to the jig contact portion and configured to be pushed up from below in the vertical direction by a jack, and
• a ratio of a first distance to an outside diameter of the upper half seal portion or the lower half seal portion is 0.01 or more and 0.1 or less when a distance in a horizontal direction between a fixing center position of the jig fixing portion with respect to the end surface and a loaded position of the jig protrusion that the jack comes into contact with and to which a force from the jack is applied is the first distance.