Metal working – Method of mechanical manufacture – Impeller making
Reexamination Certificate
2000-03-13
2001-11-27
Rosenbaum, I. Cuda (Department: 3726)
Metal working
Method of mechanical manufacture
Impeller making
C029S525110
Reexamination Certificate
active
06321447
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a concentric wrench for tightening or loosening a fitting at the bottom of a blind access opening in a turbine, and particularly relates to a concentric wrench for tightening or loosening a recessed fitting for a pressure tap from the outside surface of the gas turbine casing and methods of using the wrench.
BACKGROUND OF THE INVENTION
Sensing devices are typically employed in internal spaces within a turbine. For example, pressure taps are often required on nozzle segments inside a gas turbine. Pressure taps are employed to measure the pressure within internal spaces inside the casing and are connected through the casing to an external pressure measuring device. Particularly, a pressure tap consists of tubing that attaches to a portion of the turbine, e.g., a nozzle segment, and passes through a penetration in the turbine casing to a location external of the casing. The penetration is typically an elongated opening or bore for access to the pressure tap fitting. Parts of the turbine are movable relative to one another during assembly and disassembly necessitating access to the fittings to connect or disconnect the fittings within the casing as applicable. As a specific example, nozzle segments in turbines are typically rotated circumferentially in the turbine casing for assembly/disassembly. This requires the pressure tap tubing to have a pressure fitting between the nozzle segment and the outer turbine casing for tightening/loosening the fitting from outside the turbine casing. There is no access to the pressure fitting from inside the turbine casing because the turbine rotor is in place.
A pressure fitting may comprise a first sub-assembly including a female threaded collar secured to a pressure transmitting conduit, the opposite end of the conduit extending into the cavity whose pressure is to be measured. The fitting also includes a second sub-assembly including a male threaded collar for threaded engagement with the female collar, the male threaded collar also being secured to a conduit extending through the blind opening in the casing to a location external of the casing. When the collars are threaded to one another, a complete pressure transmitting passage from the cavity through the connected conduits to the external pressure sensor is provided. Consequently, a mechanism is necessary to enable tightening/loosening the fitting including connecting/disconnecting the collars relative to one another through a blind opening from a location external of the turbine casing.
BRIEF SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a concentric wrench for insertion into the blind access opening in the casing and which wrench is capable of rotating the first and second sub-assemblies of the fitting relative to one another to enable connection/disconnection or loosening/tightening without direct, i.e., with blind access to the fitting. To accomplish this, the concentric pressure tap wrench of the present invention includes an outer tube having gripping surfaces, for example, flats, along an interior surface of the outer tube adjacent one end thereof for engaging flats formed on the first sub-assembly, for example, the female threaded collar. The opposite end of the outer tube also has a gripping surface by which the tube can be gripped by a tool for holding the tube. A second elongated element has flats along one end thereof for engagement with corresponding flats on the second sub-assembly. Preferably, the second sub-assembly also includes a hex nut secured to the conduit at a location closely adjacent the male threaded collar. The second elongated element preferably comprises a tube for disposition in the outer concentric tube and likewise has gripping surfaces adjacent an opposite end for engagement by another tool.
In using the concentric pressure tap wrench hereof, the outer and inner tubes are disposed about the pressure transmitting conduit extending from the fitting through the blind access opening to a location external to the casing. The tubes are disposed in the blind access opening of the casing and the flats thereof engage the corresponding flats of the first and second sub-assemblies of the fitting. By holding the outer tube against rotation, e.g., by engaging a tool against its outer gripping surface accessible externally of the casing, and engaging another tool with the gripping surface of the inner tube to rotate the latter relative to the outer tube, it will be appreciated that the sub-assemblies and hence the collars can be rotated relative to one another in directions loosening or tightening the threaded connection between the collars.
In a preferred embodiment according to the present invention, there is provided for use in rotating machinery having a stationary outer casing and an access opening through the casing to a fitting recessed in the opening, the fitting including relatively rotatable first and second members for loosening or tightening first and second parts of the fitting relative to one another, a concentric wrench affording blind access through the access opening to the members of the fitting comprising an elongated hollow outer tube for disposition in the opening and having flats formed along an interior surface adjacent a first end thereof for engaging the first part of the fitting and an elongated inner element for disposition in the opening and within the outer tube, the element having flats adjacent a first end thereof for engaging a second part of the fitting, opposite ends of each of the tube and the element having gripping surfaces engageable by tools external to the casing for rotating the tube and the element relative to one another to loosen or tighten the first and second parts of the fitting relative to one another.
In a further preferred embodiment according to the present invention, there is provided in rotating machinery having a stationary outer casing and an access opening through the casing to a fitting recessed in the opening and wherein the fitting includes relatively rotatable first and second members for loosening or tightening first and second parts of the fitting relative to one another, a method of loosening or tightening the parts of the fitting relative to one another comprising the steps of inserting an elongated hollow outer tube into the opening, engaging a gripping surface on an interior surface portion of the outer tube adjacent one end thereof with the first member and disposing an elongated element within the outer tube, engaging a gripping surface on the element adjacent one end thereof with the second member, while holding an opposite end portion of one of the tube and the element and the first or second member engaged thereby against rotation, rotating another of the tube and the element and the first or second member engaged thereby to relatively rotate the first and second members to loosen or tighten the parts relative to one another.
Accordingly, it is a primary object of the present invention to provide a concentric pressure tap wrench enabling tightening/loosening of a pressure fitting in a blind access opening in a turbine.
REFERENCES:
patent: 3779105 (1973-12-01), Triplett et al.
patent: 4329892 (1982-05-01), Daigle
patent: 4393583 (1983-07-01), Zwald
patent: 4522090 (1985-06-01), Kittle
Drlik Gary Joseph
Gibler Edward Eugene
Laurer Kurt Neal
Cuda Rosenbaum I.
General Electric Company
Nixon & Vanderhye
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