Product category:
Seals
News Release from: FTL Seals Technology | Subject: Custom sealing systems
Edited by the Engineeringtalk Editorial
Team on 13 November 2001
New elastomeric sealing system for hot
tapping
Working with Advantica Technologies, FTL Seals Technology has developed and patented a primary elastomeric sealing system for use with a process known as hot tapping
Working with Advantica Technologies, FTL Seals Technology has developed and patented a primary elastomeric sealing system for use with a process known as hot tapping Natural gas is transported from on-shore terminals to regional distribution points at high pressure by large bore underground pipelines
This article was originally published on Engineeringtalk on 5 Jun 2008 at 8.00am (UK)
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From time to time in order to connect an off-take or branch connection to the main pipeline, a Tee connection is made to the main pipeline, this process is known as "hot tapping".
Engineers from Advantica Technologies developed the system, which removes the need for all site welding and hot work.
A split sleeve assembly, which incorporates a flanged connection, is clamped to the parent pipe at the point where the tee connection is to be introduced.
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Prior to the tapping process the annular space between pipe and split sleeve assembly is filled with a special epoxy grout, this grout is used to carry the combined loads generated by internal pressure, temperature variation and pipeline loads such as bending and torsion.
Tony Snowdon, Marketing Director for FTL Seals said: "The design of the seal was particularly challenging as it to had to seal operational pressures up to 7 MPa, on a convex pipe surface and with variations in eccentricity of up to 5mm.
"An extended seal life of up to fourty years was a design requirement, so material choice was critical.
Extensive material testing and FEA analysis has been undertaken to determine material compatibility, resistance to explosive decompression, compression set characteristics, before a suitable material was chosen." The flanged connection is used as a location for a sliding gate valve on top of which a standard "tapping drill" machine is mounted.
A pilot drill, within the tapping machine, penetrates the pressurised pipeline, filling the machine with gas.
Air is then purged from the tapping machine.
A cutting head makes the tap into the line, retaining the cut coupon of pipe and withdrawing through the gate valve.
The gate valve isolates the tapping machine from the pipeline, which is removed.
The branch connection is added and the gate valve opened, allowing gas to flow into the branch line.
This "hot tap" technique will enable Advantica to offer a new lower cost technology to oil and gas pipeline operators worldwide, a specialist area where FTL Seals Technology is already working on many new and challenging projects. Request a free brochure from FTL Seals Technology ...
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