Continental Oil Company

Conoco Inc.

Donald H Oertle

Marvin L Peterson

Norman W Hein, Jr

Frederick J Radd

Fred J Radd

Burton M Casad

Randall G Ivie

Louis H Wolfe

Steven E Hawkins

Richard M Vennett

Early detection of cracks in structural members subject to stress is accomplished before cracks traverse the member by

Crack detection by electrical resistance

At least two types of reflective or emissive materials are applied in alternating manner to a pile or other object to be moved. Ultraviolet energy is emitted toward the materials and reflections or emissions therefrom are received by appropriate detector elements which convert the different respective reflected or emitted energy spectra into corresponding electrical signals for use by a processor device to determine the distance and rate which the pile or object is being moved. The calculated information is channeled to a suitable display and a permanent recording device.

Displacement measurement device and method

A dual element strain gauge is placed near a welded or otherwise constrained joint on a structural member so as to provide a constraint factor. The location for the strain gauge must be selected to provide constraint factor that is preferably near either maximum or minimum value. The strain gauge is monitored to detect a change in the initial constraint factor, which indicates failure has begun or is imminent.

Constraint factor for structural monitoring

Initiation and propagation of cracks in materials is detected and monitored by (a) adhering an acoustical emitter to the area of the material to be monitored, and (b) monitoring for acoustical signals emitted by the adhered emitter, said signals produced by cracks in the material initiating in or propagating into the acoustical emitter. An acoustical emitter such as brittle plastic, glass rods or strips and metal such as tin or cadmium can be used.

Acoustic emission for detection and monitoring of crack initiation and

Crack initiation in metallic structural members subject to cyclic loading is predicted by sensing metallurgical changes taking place as a result of the cyclic loading. Fatigue loading produces a cycle comprising a condition described as fatigue relaxation followed by fatigue intensification. By monitoring this cycle, measured strain for a known applied load will increase or decrease. By monitoring the change in strain load, crack initiation can be predicted as fatigue relaxation becomes fatigue intensification. In a preferred embodiment, the strain gauge is mounted beneath a patch excluding ambient atmosphere during monitoring of the structural members.

Structural failure detection method

Early detection of cracks in non-permeable, structural members subject to stress is effected before the cracks traverse the member by:

Early crack detection

The integrity of corrosion prevention sheaths of corrosive-resistant metal employed to prevent member corrosion on off-shore platforms is monitored by incorporation of a pressure sensing line sealed into the zone between the sheath and the member. This apparatus allows monitoring members in the splash zone as well as stressed areas such as weld joints which are subject to corrosive environments.

Method of preventing corrosion of joints of steel structures submerged

Corrosion at the interface of concrete and reinforcing steel in a concrete structure is determined by placing a hollow hydrogen-permeable probe in the concrete, connecting a getter-ion pump to the probe, and monitoring the output current of the getter-ion pump. An increase in output current is indicative of corrosion occurring at the probe-concrete interface, which in turn is indicative of corrosion at the interface of concrete and steel reinforcing members at comparable locations in the structure.

Method of detecting corrosion at interface of concrete and reinforcing

This invention provides a method for monitoring early formation of cracks in permeable or porous materials which comprises affixing a frangible fluid impermeable enclosure to the permeable or porous surface to be monitored such that a crack forming in the permeable material will destroy the integrity of the frangible fluid impermeable enclosure and provide a passage for a fluid to flow between the environment and the enclosed space, then sealing a fluid passageway in fluid communication from the enclosed space to a source of pressure different than ambient at the permeable material and to a pressure sensor; then imparting a pressure different than ambient to the enclosed space through the fluid passageway and thereafter monitoring the internal pressure in the enclosed space and fluid passageway with a pressure sensor such that a crack in the permeable material will destroy the integrity of the enclosed space and allow passage of fluid between the environment and the enclosed space which is detected by the pressure sensor.

Porous material crack detection

Early detection of cracks in nonpermeable, structural members subject to stress is effected before the cracks traverse the member by forming a plurality of cavities in the member or adjacent thereto in which a plurality of fluids at differing pressures are confined and monitored, such that a crack in the structural member penetrating between at least two cavities allows passage of fluid between the cavities and is thus detected by a pressure sensor. The apparatus and process is particularly applicable to early detection with vacuum of cracks in the heat affected zone adjacent to welds on critical stressed members of an offshore platform. A strain gauge system may be employed in conjunction with the crack detection system.

Early crack detection with multi-pressure system

An insertion-type hydrogen probe with a defined active length is described. The probe is formed of a thin-walled, hydrogen-permeable material, and a hydrogen-impermeable liner inside the probe blocks out all but the defined active section of the probe. The interior of the probe is subjected to high vacuum, and the hydrogen permeation through the active portion of the probe is determined, for example, by the current output of an ion pump used with the probe. To prevent bimetallic cell interface effects, the probe is constructed so that only a single metal is exposed to the primary environment being studied.

Hydrogen probe with limited active area

A low profile port closure apparatus which consists of a port positioned on the vessel to be sealed, a threaded sealing means for effecting fluid-tight closing of said port, and pressure retaining manifold structure which enables sealing positioning and removal of the sealing means in said port, and which manifold means is removable from operative position.

Port closure apparatus for differentially pressured vessels

A process change sensor comprising a tubing means, a first electrode positioned at one end of the tubing means for contact with a process medium, a second, permeable electrode positioned inwardly in the tubing means from said first electrode, a porous body separating said second electrode from said first electrode, means for supplying electrolyte through said tubing means to said second electrode whereby said supplied electrolyte can flow through said porous body to said first electrode, and means for measuring the change in EMF between said first and second electrodes as a result of changes in the process medium at said first electrode.

Process change sensor

Apparatus for connecting the open end of an elongated hollow probe member to a chamber whereby the interiors of the probe member and the chamber can be evacuated while the probe member and chamber are disconnected from each other and then the probe member sealingly connected to the chamber while maintaining the evacuation.

Diffusion monitoring apparatus

A simple apparatus and process for monitoring a selected component of a fluid system are provided wherein the apparatus comprises a simple diffusion probe, an electronic pumping means and a reading means whereby the diffusion and pumping rate are read directly as electrical current.

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Ponca City, OK, United States of America

Donald H Oertle