Clock Spring Company, LP

Clock Spring Specifications

admin — Tue, 21 Feb 2012 20:41:27 +0000

Clock Spring Specifications

Clock Spring specifications show its design to repair/reinforce damaged or corroded sections of pipe with up to 80% wall loss.

Sleeve Specification:

Number of wraps: 8 layers full cured laminate structure. Each layer 0.06” thick.
Nominal thickness: 0.500 inches (13mm) when installed.
Service temperature: -29°C to +77°C.
Material: E-glass continuous strand fibre all aligned in hoop direction and held within a polyester resin matrix.
Width: 11.5” ⁺/_- 0.5” (292mm ⁺/_- 13mm).
Service life: >50 years.

Adhesive Specification:

Lap shear strength: 1200 psi (8.27 MPa).
Shelf life: 12 months from date of manufacture.

Filler Specification:

Compressive strength: >8000 psi (55 MPa).
Shelf life: 12 months from date of manufacture.

Mechanical Values

Note: All mechanical properties are measured on specimens that have been subject to an accelerated ageing process (in line with standard aerospace procedures) and saturated with water at elevated temperatures.

	Circumferential	Axial
Tensile modulus	35.5 GPa (5 x 10⁶ psi)	9.7 GPa (1.4 x 10⁶psi)
Tensile strain to failure	1.6%	0.4%
Tensile strength	469 MPa (68 ksi)	40 MPa (5.8 ksi)
Thermal expansion coefficient	6.02 x 10^-6	32.6 x 10^-6
Poisson’s ratio	0.31	0.07

Shear modulus	0.86 GPa (125 ksi)
Shore A hardness	Minimum 40
Glass transition	104°C (220°F)
Lap shear strength to steel	10.3 MPa (1500 psi)
Aged lap shear strength	8.3 MPa (1200 psi)
Pipe survival tests	151 tests completed
Performance testing	20,000 hour tests completed (2.3 years duration) which are more representative of long term behaviour than the 1000 hour (42 days tests) required by ISO and ASME. In-service monitoring of repairs, subsequent removal and testing for durations up to 7 years completed and reported.20 ksi (138 MPa) long-term allowable stress derived for 50 year life.

Installation Tips – Offshore HP Riser Repair

admin — Tue, 21 Feb 2012 16:03:27 +0000

HP Riser Repair

The following report is a pictorial and text account of procedures and operational techniques employed for the export riser repairs. The report is not meant as a technical report but serves as a QA/QC document for the installation of the Clock Spring system.

A HP riser has experienced extensive corrosion with wall loss of 82%, which is centered around the splash zone area.

A series of UT and visual inspection was conducted on the riser by the operator. The result was up to 82% wall loss is experienced by the riser, especially at the splash zone area. The previous coating has failed allowing the seawater to interact with the riser’s metal surface, causing extensive corrosion.

Engineering Analysis at Clock Spring Reinforced Area

B31 Assessment / Deepest Defect

Defect Depth 8.1mm
Defect Length ~250mm
Wall Loss % 82%
Pristine Yield Pressure of the Pipe 343.36 Bar
Failure Pressure of Reinforced Pipe 421.2 Bar
Reinforced Failure to Pristine Yield Ratio 1.06
Suitability of Clock Spring Repair √

Pipe Diameter: DN 200 mm
Nominal Thickness: 10.00 mm

Site Installation

The installation of the Clock Spring® was conducted within 2 days in approximately 8 hours.

Installation Photos

Field Report- Tight Clearance – Hydrocarbon Line Corrosion – Offshore

admin — Wed, 15 Feb 2012 22:54:34 +0000

Offshore Repair Tight Clearance

Location:

West Malaysia
Offshore

Pipe Details:

8” diameter operating at 10 bars containing hydrocarbon at ambient temperature.

Defect Details:

The defect is external corrosion with wall loss of 40%.
Tees are located both before and after the defect.
A 3” pipe hangs above the repair section with a tight clearance of only 3 inches.

Repair Application:

Clock Spring reinforcement sleeve is used and applied using the hand spool technique to meet the tight clearance restriction.

Repair Time:

The repair took 45 minutes to complete.

Field Report – Offshore Riser Repair

admin — Wed, 15 Feb 2012 22:36:38 +0000

Offshore Riser Repair

Completed Repair (Center of Photo)

Location:

West Malaysia
Offshore Riser

Pipe Details:

8” diameter
40 Bar operating pressure
30°- 40°C ambient temperature

Defect Details:

Extensive external corrosion up to 82% wall loss covering circumferential area, especially at the mean sea level (splash zone).

Repair Application:

Clock Spring reinforcement sleeve with marine type chemicals utilised. These chemicals have been tested for sub-sea application and will cure even when submerged. The total length of riser being repaired is 5.2 meters.

Repair Time:

Installation was completed within 9 hours, spanning 1 ½ days.
The splash zone section of the riser was repaired within one hour as the crew only had a one hour window at low tide.

Field Report – Offshore Tight Clearance Repair

admin — Wed, 15 Feb 2012 19:51:08 +0000

Offshore Tight Clearance Repair

Location:

West Malaysia
Offshore (Top Side)

Pipe Details:

8” diameter operating at 10 bars containing hydrocarbon at ambient temperature.

Defect Details:

Piping located at cellar deck with wall loss of 50% at 6 o’clock position.
The length of the defect is approximately 200mm long.
Repair section of the piping is located in close proximity to another 12” pipe.

Repair Application:

Clock Spring® reinforcement sleeve was used as a repair method using the hand spool technique.
Clock Spring® is able to be used even in areas with tight clearance restrictions.

Repair Time:

The repair took 40 minutes to complete.

Field Report – Process Plant Pipe Corrosion Repair

admin — Wed, 15 Feb 2012 17:26:43 +0000

Process Plant Corrosion Repair

Location:

Malaysia
Process plant

Pipe Details:

2” – 18” diameter
Process pipelines

Repair Application:

Major rehabilitation program of over 654 pipe support locations.
Corrosion issues due to water entrapment and galvanic conditions as well as erosion due to pipeline movement.
Pipe was lifted at each support location and the pipe surface manually cleaned using power brush techniques.
Pipe supports installed within 15 minutes and once cured (within 1 hour) the pipe was lowered back onto the support.

Field Report – Discharge Pump Leak Repair – Contour

admin — Wed, 15 Feb 2012 17:00:53 +0000

Discharge Pump Repair with Contour

Location:

West Africa
Offshore

Component Details:

6” inlet pipe on discharge pump
5 bar pressure

Repair Application:

Small pin hole leaks close to “tee” girth weld.
Temporary shut down of the pump whilst area manually cleaned and pin hole sealed with leak sealing compound.
Clock Spring Contour application over the complete complex tee geometry and all affected girth welds. Repair designed in accordance to ISO TS24817.

Field Report – High Temperature Pipeline Girth Weld Repair

admin — Wed, 15 Feb 2012 16:15:53 +0000

High Temperature Pipeline Girth Weld

Location:

West Africa
High temperature pipeline

Pipe Details:

30” main oil export line
70 bar operating pressure
+70°C operating temperature

Repair Application:

General external corrosion at girth welds due to poor application of field joint coatings.
Standard girth weld bridging technique utilised with high temperature Clock Spring system, suitable for up to 120°C service temperature.

Field Report – New Pipeline Construction with Pipe Support Application

admin — Wed, 15 Feb 2012 15:46:45 +0000

New Pipeline Construction – Installation of Pipe Support Sleeves

Location:

Luxembourg

Pipe Details:

12” domestic water line

Repair Application:

Design guidelines requested protection of the pipe at each support location.
Pipe supports fitted during the line construction to prevent all future problems associated with crevice, galvanic corrosion and erosion.
After installation corrosion coating was applied and the pipe support fabrication then completed.

Field Report – Offshore Structural Repair with Snap Wrap

admin — Wed, 15 Feb 2012 15:19:30 +0000

Offshore Structural Repair using Snap Wrap

Location:

Middle East
Offshore

Pipe Details:

14” heavy wall structural cross member.
8 metre repair length.

Repair Application:

Severe external corrosion (up to 80%) metal loss on structural member designed to hold riser support clamps.
Engineered heavy wall composite sleeve, manufactured in 600mm widths using bi-axial glass architecture.
Extensive filler application and molding to rebuild pipe surface to original outer diameter and sleeves installed and cut to length in a brick wall fashion.
Once completed riser holding clamps reinstated over the offshore structural repair area.