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Welding
Clamps
The Need
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Welding and
pipefitting are related skills. While welding technology has advanced in recent years,
methods of fitting pipe remained primitive. Traditional methods of pipe fit-up which use
brute force are still common: welding lugs on pipe for alignment, knocking them off with a
hammer, cleaning up the spot, and patching the pipe. These unsafe methods cause quality
control rejections, which means lost productivity, aggravation, and frustration.
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Cage Clamp
Single Jackscrew Chain Clamp
Double Jackscrew Chain Clamp
Double Chain Clamp
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The
Technology
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In general,
clamps are used to align and reform pipe for welding. Old cage clamps are a modest
improvement from the traditional methods, but still require hammering, causing the clamps
to go out of shape. This deformity is brought to the next fit-up. Cage clamps are also
limited to one size of pipe and lack versatility. Chain Clamps from Mathey Dearman can fit-up elbows, tees, flanges and other
pipe fittings. Chain Clamps are reforming clamps, able to take out "Hi-Lo"
without wedges. Generally chain clamps are recommended for alignment and moderate
reforming of nominally standard, light, and medium wall thickness.
Universal Chain Clamps offer the most
versatility of any clamp available. Sliding jackbars allow for a wide rang of
applications. Recommended for use with miter and flange fit-ups.
Single Chain Clamps will typically align
and reform out-of-round pipe up to schedule 40 wall thickness. Where no reforming is
required, pipe over schedule 40 can be aligned with Single Chain Clamps. Depending upon
the type of pipe and the out-of-round condition, minor reforming of pipe over schedule 40
may be possible with this clamp. It features a single jackscrew on each jack bar. Optional
spacing screws allow the gap to be set quickly and precisely. Double jackscrews allow for
reforming pressure to be applied to either side of the weld.
Double Chain Clamps (vessel clamps) will
typically align and reform out-of-round pipe up to schedule 80 wall thickness, depending
on the type of pipe and out-of-round condition.
Where heavy-duty reforming is required, Rim
Clamps are recommended. The jackscrews exert pressure on specified high points for precise
alignment. Ideal for application where 100% weld and grind is needed without releasing
clamp pressure.
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The
Benefits
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Rim Clamp |
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Chain Clamps are versatile:
each clamp can fit-up elbows, tees, flanges, and other pipe fittings. All carbon steel
Chain Clamps are zinc plated to resist spatter and corrosion. On the average, one Chain Clamp costs about 40% less
and weighs about 77% less than the required number of cage clamps to cover the same range
of pipe diameter. These benefits make the Chain Clamp very portable.
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The Rim Clamp is ideal for
applications where the user needs 100 % weld and grind without releasing clamp pressure.
The Rim Clamp removes Hi-Low up to 2-1/2" wall thickness. This prevents cracking of
partially completed welds. The Rim Clamp allows the user to weld, grind, and reweld before
removing the clamp. |
Status
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Chain Clamps and Rim Clamps
from Mathey Dearman have been used in various fields and applications such as cooling
towers, air conditioning systems, refineries, power plants, environmental protection
equipment, public utilities, berths or docks, boiler equipment, offshore platforms, etc. |
Points of Contact
- Kris Boyne, Mathey Dearman, International
Sales, P.O. Box 472110, Tulsa, Oklahoma 74147-2110, Phone: (918) 258-7311 &
1-800-725-7311, Fax: (918) 251-5200, email: kris@mathey.com.
References
- Mathey Dearman Main Catalog, available on Mathey Dearman Web
site:
http://www.mathey.com/
- Mathey Dearman Chain Clamp Catalog, available on Mathey
Dearman Web site: http://www.mathey.com/
Disclaimer Statement
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Neither the Construction
Industry Institute nor Purdue University in any way endorses this
technology or represents
that the information presented can be relied upon without further investigation. |
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