GB2248304A - Monitoring load cycles on chains - Google Patents

Monitoring load cycles on chains Download PDF

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Publication number
GB2248304A
GB2248304A GB9114962A GB9114962A GB2248304A GB 2248304 A GB2248304 A GB 2248304A GB 9114962 A GB9114962 A GB 9114962A GB 9114962 A GB9114962 A GB 9114962A GB 2248304 A GB2248304 A GB 2248304A
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GB
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Application
Patent type
Prior art keywords
gauge
chains
apparatus
monitoring
strain gauge
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9114962A
Other versions
GB9114962D0 (en )
Inventor
Colin Carmichael
David Muir
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fleetfusion Offshore Ltd
Original Assignee
FLEETFUSION OFFSHORE LIMITED
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01LMEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00Apparatus for, or methods of, measuring force, e.g. due to impact, work, mechanical power, or torque, adapted for special purposes
    • G01L5/04Apparatus for, or methods of, measuring force, e.g. due to impact, work, mechanical power, or torque, adapted for special purposes for measuring tension in ropes, cables, wires, threads, belts, bands or like flexible members
    • G01L5/10Apparatus for, or methods of, measuring force, e.g. due to impact, work, mechanical power, or torque, adapted for special purposes for measuring tension in ropes, cables, wires, threads, belts, bands or like flexible members using electrical means
    • G01L5/102Apparatus for, or methods of, measuring force, e.g. due to impact, work, mechanical power, or torque, adapted for special purposes for measuring tension in ropes, cables, wires, threads, belts, bands or like flexible members using electrical means in which the sensor is located at a non-interrupted part of the member

Abstract

Apparatus for monitoring applied loads in chains comprises strain gauges 1 which are positioned on a stud 2 of a link 3 of a chain 4. The gauges 1 are arranged in two sets of two with each gauge 1 at right angles to the other of the set. The gauges 1 are wrapped in a protective coating of PTFE tape, wax, metal foil and a waterproof material. Wires 5 from each gauge 1 are connected to a data processor 6. The data processor 6 produces a signal which represents the movement of the gauges and thus the loading on the chains. <IMAGE>

Description

Apparatus for and Method of Monitoring Load Cycles Qn Metal Components This invention relates to apparatus for and a method of monitoring load cycles on metal components. The invention has particular application in the monitoring of anchor chains.

Heavy-duty metal chains are widely employed in the oil industry to moor drill ships and semi-submersibles or other equipment in position. Such chains may be subject to the most adverse weather and sea conditions, sometimes being partially under salt water and in the open air and wound through the winching apparatus as required. The cyclic changes in strain and stress to which these chains are subjected result in a continuous relaxation and stretching of the metal. It is of considerable value to be able to monitor these cycles.

According to the present invention there is provided apparatus for monitoring loads applied to chains, comprising a strain gauge, means for securing the strain gauge to a stud of a chain link, data processing means and electrical connector means connecting the strain gauge to the data processing means, the data processing means being arranged for converting information relayed from the strain gauge into a readable form.

Preferably, a number of strain gauges are provided fitted orthogonally with respect to each other, to assess strain in both axial and longitudinal directions.

Preferably, the strain gauge is protected by being wrapped against the stud with PTFE tape such as covered with wax and wrapped in metal foil such as aluminium, and the whole wrapped once more in a waterproof material such as wax.

Preferably, the data processing means includes an antononous data acquisition unit (ADU) supervisor which has interface modules to convert analogue signals from the gauge to digital signals which are processed by a microprocessor to provide a data output.

Further according to the present invention there is provided a method of monitoring applied loads in chains, comprising securing a strain gauge to a stud of a chain link, providing a protective cover for the gauge against its environment, and monitoring signals produced by the gauge to provide data from which information concerning cyclic load fluctuations may be ascertained.

An embodiment of the invention will now be described by way of example with reference to the drawings in which: Fig. 1 shows in schematic form apparatus for monitoring applied loads in chains; and Fig. 2 is a partial cross section of part of the apparatus of Fig. 1.

Apparatus for monitoring applied loads in chains comprises strain gauges 1 which are positioned on a stud 2 of a link 3 of a chain 4. The gauges 1 are arranged in two sets of two, each set being arranged generally parallel to the other. Within the set, each gauge 1 is at right angles to the other. The gauges 1 are wrapped in Teflon film (not shown), aluminium foil la and wax or waterproof material lb. Wires 5 from each gauge 1 are connected via a shielded cable 5a to a data processor 6. The junction-between the wires 5 and the cable 5a is protected by a heat-shrinkable wire splice sealant 7.

The data processor 6 comprises an ADU supervisor 8 which converts signals from the gauges 1 to digital data which is processed by a microprocessor 9 and printed out on a printer 10. The ADU supervisor 8 comprises ADU interface modules 11 which include a microcard real time logging and control module 12 and an ADU supervisor basic programme 13.

The chain 4 is carried by a winch 14 which has a load cell sensor 15 mounted between shaft and bearing to determine the preload applied to the chain 4. This information is used when making calculations as to applied loads.

The movement of the gauges is thus converted into actual loading on the chains by the computer. The print out shows the date, time and actual loading.

From this information it is possible to estimate the working life of a chain and the possibility of metal fatigue occurring.

The gauges thus monitor the changes in strain over a period of time and the printed read-out provides valuable information concerning the cyclic loads applied to the chain. The microprocessor microcard real time logging and control facility can thus monitor changes over a set period.

This information may be put to good use by the operatives in the oil industry to prevent semi-submersibles and other expensive equipment breaking free and being both a safety hazard and a loss to the operating company.

Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims (7)

1. Apparatus for monitoring loads applied to chains, comprising a strain gauge, means for securing the strain gauge to a stud of a chain link, data processing means and electrical connector means connecting the strain gauge to the data processing means, the data processing means being arranged for converting information relayed from the strain gauge into a readable form.
2. Apparatus as claimed in Claim 1, wherein a number of strain gauges are provided fitted orthogonally with respect to each other, to assess strain in both axial and longitudinal directions.
3. Apparatus as claimed in Claim 1 or 2, wherein each strain gauge is protected by being wrapped against the stud with PTFE tape, covered with wax, wrapped in metal foil and the whole wrapped once more in a waterproof material.
4. Apparatus as claimed in any one of the preceding Claims, wherein the data processing means includes an antononous data acquisition unit (ADU) supervisor having interface modules to convert analogue signals from the gauge to digital signals which are processed by a microprocessor to provide a data output.
5. A method of monitoring applied loads in chains, comprising securing a strain gauge to a stud of a chain link, providing a protective cover for the gauge and monitoring signals produced by the gauge to provide data from which information concerning cyclic load fluctuations may be ascertained.
6. Apparatus for monitoring loads applied to chains substantially as hereinbefore described and with reference to the accompanying drawings.
7. A method of monitoring applied loads in chains substantially as hereinbefore described and with reference to the accompanying drawings.
GB9114962A 1990-08-24 1991-07-11 Apparatus for and method of monitoring load cycles on metal components Withdrawn GB9114962D0 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9018678A GB9018678D0 (en) 1990-08-24 1990-08-24 Apparatus for and method of monitoring metal fatigue

Publications (2)

Publication Number Publication Date
GB9114962D0 GB9114962D0 (en) 1991-08-28
GB2248304A true true GB2248304A (en) 1992-04-01

Family

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Family Applications (2)

Application Number Title Priority Date Filing Date
GB9018678A Pending GB9018678D0 (en) 1990-08-24 1990-08-24 Apparatus for and method of monitoring metal fatigue
GB9114962A Withdrawn GB9114962D0 (en) 1990-08-24 1991-07-11 Apparatus for and method of monitoring load cycles on metal components

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB9018678A Pending GB9018678D0 (en) 1990-08-24 1990-08-24 Apparatus for and method of monitoring metal fatigue

Country Status (1)

Country Link
GB (2) GB9018678D0 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6774320B2 (en) * 2001-11-30 2004-08-10 Gerald S. Simons Standard attachment fittings for wire rope and chain enhanced to also perform load weighing functions

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4283942A (en) * 1979-05-25 1981-08-18 Fishfader Stanley S Load measuring device
GB2205411A (en) * 1987-06-01 1988-12-07 Hugh Michael O Pratt Load cell

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4283942A (en) * 1979-05-25 1981-08-18 Fishfader Stanley S Load measuring device
GB2205411A (en) * 1987-06-01 1988-12-07 Hugh Michael O Pratt Load cell

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6774320B2 (en) * 2001-11-30 2004-08-10 Gerald S. Simons Standard attachment fittings for wire rope and chain enhanced to also perform load weighing functions

Also Published As

Publication number Publication date Type
GB9018678D0 (en) 1990-10-10 grant
GB9114962D0 (en) 1991-08-28 grant

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)