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Issue Five of Weld Purging World - September 2019

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Published by marketing, 2019-09-11 04:42:04

Weld Purging World - September 2019

Issue Five of Weld Purging World - September 2019

Keywords: weld purging,weld purging world,huntingdon fusion,purgeye,weld purge monitor

ISSUE 5 September 2019

In September’s Issue:

• NEW Ask the Expert
• 2019 Calendar of Exhibitions and Events
• HFT® News: Pipestoppers® Division, SPE Offshore Europe

and more....
• Product News: PurgEye® 100, Weld Purge Plugs and Rubber

• Technical Article: Seven Tips for Weld Purging


Huntingdon Fusion Techniques HFT® are proud members of:



Ask the Expert 3
HFT® News: HFT® Pipestoppers, Offshore Europe and more 4-5
Product News 6-7
More Product News
Technical Paper: Seven Tips for Weld Purging 8


Dear Reader,

Welcome to September’s Weld Purging World.

In this month’s issue we turn your questions into answers
with our new ‘Ask the Expert’ feature.

Our Chairman, Ron Sewell also gives us details on how
our Pipestoppers® Division became part of our science of
Weld Purging.

If you have any news or would like to be featured in our
magazine, then please get in touch.

Thank you for reading!

Best wishes,

Marketing and Social Media Manager
[email protected]



HFT®’s Technical Sales Manager: Luke Keane

In this month’s Weld Purging World, we take your questions to our
experts! We ask Technical Sales Manager Luke Keane, ‘What is the
difference between PurgeNet™ and PurgeLog™?

Luke: “PurgeNet™ is the internal
software, which is built into most
of our Weld Purge Monitors. This
allows us to control the relay
signal, meaning we can connect
to other devices, like a welding
power source etc.
PurgeLog™ is a program for a
PC, which we supply on a USB stick that allows data from the
monitor to be downloaded to a PC/windows format.”
Got a question you’d like one of our experts to answer? Then get in touch!
We might also feature the question in an up and coming issue to share with others.



Ron Sewell, Chairman for HFT® tells us how the Pipestoppers®
Division came to be part of the HFT® science of Weld Purging
and the technology that has since evolved.

“In the 1970’s as we were beginning to develop our expertise
in Weld Purging, we were selling a lot of our white Nylon Plugs
for simple weld purging applications. As our business grew and
numbers started to increase, the company manufacturing our
Nylon Plugs came up for sale, due to the retirement of the owners.

HFT purchased that organisation and took over a large customer
list of companies buying the plugs for other applications.

One of the largest customers was Cob Industries, a USA
based company who had a large business in supplying pipe
plugs all over the US and to many companies overseas as

It was soon evident to HFT as well as Cob that many of our
customers were the same, especially in the international
petrochemical field, so an arrangement was made to work
with Cob as our Weld Purging Products Distributor in the
USA. Since then Cob has continued their close relationship
with HFT to become our largest international customer.

The size of HFT started to increase quickly throughout our formative years and it was necessary to
create a separated division to look after sales of plugs to the non-welding industry.

So, we created a separate Pipestoppers Division, leaving
the welding related products in our Weld Purging Division.

There are thousands of applications our Pipestoppers®
can support for so many industries. Some of these
include: Construction of refineries and similar large oil
and gas related plants, where plugs are required to block
open ended pipework with leak tight seal. Construction
of factories and housing for plugs used to test leak
tightness of foul water systems. Boating, yachting and all
marine businesses where holes are frequently there to
be blocked and an endless supply of water trying to enter. Use in aircraft construction and repair of
submarines. The list really is endless, from very high tech to very low tech applications.”


SPE Offshore Europe

Earlier this month, HFT® CEO Georgia Gascoyne and Technical Sales
Manager Luke Keane travelled up to Aberdeen in Scotland to visit Offshore
SPE Offshore Europe is recognised by offshore E&P professionals as
Europe’s leading E&P event.
Georgia said: “It was another great show! We we able to network with
potential customers as well as catch up with our Distributors and customers!”

88” Low Profile Stoppers

Our Pipestoppers® Division recently manufactured 3 x 88’’ Low
Profile stoppers for a customer in Holland to stop fumes travelling
down a pipeline during welding.
Manufactured from tough, robust fabric, these Low Profile
Inflatable Stoppers are available in sizes 6 to 88” (150 to 2,235
mm) and provide excellent grip inside the pipe, with an effective
airtight seal.


16 – 21 September 18– 20
EMO Hannover September
Hannover, Germany

Bangkok, Thailand

Exhibiting! Distributor Exhibiting!

11 - 14 November 26 - 28th November
Fabtech Stainless Steel World
McCormick Place, Chicago, IL, USA MECC Maastricht, The Netherlands

27 - 28 November Exhibiting!
Ifema, Madrid, Spain 11 - 14 November
Adnec, Abu Dhabi


1. Weld Purge Monitor for On-Site Conditions


Inert gas welding requires the elimination of oxygen from the
weld zone during the welding of reactive metals including
stainless steel.

Before the welding process begins, the oxygen level must be
reduced to a required minimum, which is less than 100 ppm
when welding stainless steel.

The low cost, hand held, battery operated PurgEye® 100,
designed and developed by Huntingdon Fusion Techniques
HFT® is perfect for obtaining zero colour, oxide free welds in stainless steel, reading accurately from
atmospheric oxygen level (20.94%), right down to 100 ppm (0.01%).

The PurgEye® 100 is IP65 rated and comes with long life sensor, leak-tight push buttons, auto
calibration and a vacuum-sealed leak-tight probe assembly. The monitor has a clear, easy to read
LCD screen with features such as a low battery icon as well as the low sensor icon. When the
monitor is not in use, an automatic sleep mode activates to conserve battery life.

The Weld Purge Monitor® was invented by HFT® in the 1970s and with over 40 years of innovation,
design and manufacturing experience, the company now has a Family of PurgEye® Weld Purge
Monitors® to measure oxygen levels from atmospheric content (20.94%) down to 1 ppm (accurate
to 10 ppm).

Ron Sewell, Chairman for HFT® said: “All of Huntingdon Fusion Techniques HFT®’s Weld Purge
Monitors® and Inflatable Tube, Pipe and Pipeline Weld Purging Systems are manufactured in the
UK. We do not sacrifice on quality. We guarantee to help you achieve zero colour welds, time and
time again.”

It is important not to use alternative low cost oxygen analyzers or other oxygen safety monitors as
they are calibrated under ambient conditions and therefore unsuitable for measuring purge levels
down to 0.01% as the PurgEye® 100 does.



Due to tight budgets, welders sometimes have to construct their own Weld Purging Equipment,
often made from materials such as paper, card, sponge or foam. Homemade dams made from such
materials can often lead to weld failures when they leak or slip from
position thus flooding the welding zone with air.

The Pipestoppers® Division of Huntingdon Fusion Techniques
HFT® manufactures a range of low cost, lightweight Weld Purge
Plugs for a variety of applications where the pipe sizes are 0.5 to 6”
(12 to 150 mm) diameter.

Ron Sewell, Chairman for HFT® said: “Our Weld Purge Plugs are
a great barrier for purging pipes when welding alloys and stainless
steel. Manufactured with a hollow shaft, these plugs can be used for weld purging smaller diameter
pipes and miscellaneous stubs.”

“They are available in a number of ready-made kits containing plugs ideally suited for the most
popular size of pipes, all of which are available for immediate delivery.”

The rubber seals are made of natural black rubber but can be manufactured with sealing rings made
of silicone, viton or nitrile rubbers, which make them suitable for use with petrochemical fluids, high
temperatures or any other conditions that might arise during use.


Lightweight Inflatable Rubber Plugs are available from the Pipestoppers® Division at Huntingdon
Fusion Techniques HFT® for sealing, stopping and blocking pipes where oils, hydrocarbons and
petrochemicals are present.

Luke Keane, Technical Sales Manager for HFT® said: “Our
Rubber Plugs are manufactured from high quality materials,
ensuring a long life span of each Plug. They serve many
purposes for a range of different industries and are highly
resistant to oils, hydrocarbons and petrochemicals.”

HFT®’s Rubber Plugs can withstand temperatures from
-40°C (-40°F) to 70°C (158°F) and are available in sizes
from 2 to 78” (51 to 1,981 mm) with each Plug having a
wide degree of flexibility in diameter.

Typical applications include: Blocking pipes, tubes, dams, inlets, storage tanks, manholes and
channels. For use in water, sewage, fluid production (milk, beer, chemicals), petrochemical,
pharmaceutical, gas pipeline systems. Restricting, diverting and bypassing flow during pipeline
maintenance or modification. Keeping pipelines free of dirt and contaminants by capping and
blocking the ends.


Effective weld purging is only achieved by making sure that oxygen is displaced from the purge zone
prior to and during welding. Any residual oxygen can cause significant loss of corrosion resistance
and a reduction in joint strength. It is therefore essential to seal the pipe either side of the joint and
maintain this seal throughout the process. The residual level of oxygen in the purge zone needs to
be consistent with the welding procedure so continuously monitoring to ensure compliance is crucial.

1 Choose a dependable sealing material

The cheapest is seldom the best so examine the options available.

Don’t be tempted to use sealing discs made from polystyrene foam, wood and cardboard - at best
they leak or emit contaminants and at worst they catch fire during the hot weld cycle.

Fig 1. These examples from the QuickPurge® range are
representative of proven purge systems. They employ

components made from materials that are stable, thermally
resistant, durable and non-toxic. They cover the entire pipe
size range between 150 and 2400 mm diameter giving an

effective seal in each case and a low purge volume.

2 Use a complete purging system

Don’t try to economise by making use of whatever happens to be around at the time. Separate seals
for the pipe and rubber tubing for the inert gas, all held together with bits of tape seldom succeeds.
Invariably this is time consuming and can only be used once.

Find systems using inflatable dams. Commercial equipment is now available in which gas flow
and pressure and purge gas quality are all pre-set. Complete monitoring instrumentation can be
incorporated to ensure a high level of quality control. These systems have been designed for multiple
use and are rugged enough to cope with site conditions whilst still reducing overall purging and
welding time very significantly.

Fig 2. These PurgElite® 1 systems employ the latest
advances in technology and are fully integrated to keep
purge times and cost to a minimum. Sizes between 25 and
600 mm diameter are available. The hoses are completely
flexible and allow the systems to transverse 90º bends.

3 Establish what level of oxygen in the purge gas is acceptable

There is plenty of published information available that establishes what the maximum oxygen content
needs to be to prevent loss of mechanical and physical properties in the weld. This depends on the
material being welded but generally, some stainless steel welding requires a low level whereas most
carbon steels are much less sensitive.


4 Take care with gas flow
Whatever system is selected ensure that the inert gas enters gas slowly. Argon is heavier than air
so introduce it slowly at the bottom of the weld purge space and discharge from the highest point.
Helium is lighter than air and needs to be inserted at the top of a cavity and removed at the base.

Fig 3. Inflated system in place
showing gas flow.

5 Don’t rush into the welding sequence
Wait until all the air has been displaced before welding. For many metals this means ensuring a
residual oxygen level below 100 ppm.
Traditionally, and a practice still followed even by major fabricators, this is based a pure guesswork.
If the oxygen content is too high, or varies during welding, oxidation occurs and this often means
rejection with the expense of re-machining, and therefore production delays. It can also lead to loss
of corrosion resistance in stainless steels.
6 Use a purge gas oxygen monitor
Don’t assume that allowing ‘plenty of time’ for purging will remove all the oxygen. If there are leaks
in the system, turbulence or simply poor quality purge gas then oxygen levels could be way above
those necessary to prevent contamination. The best solution is to use a device capable of accurate
and reliable measurement of oxygen level.

Fig 4. Purge gas oxygen monitor. These instruments
have been specially designed for rugged use during
site welding and can measure oxygen content as low
as 10 ppm. They may be hand held, desk mounted or

boxed for “ON SITE” use.

7 Read published information about purging
There’s plenty of it and examples are shown below. Learn from the experience of others rather than
using trial and error methods that could cost time and necessitate re-welding.

Argweld products from
Developments in weld purge gas oxygen monitoring technology. Stainless Steel World. March 2015.
Guide to weld discoloration levels in stainless steel. American Welding Society. AWS D18.2:1999
Choosing an effective weld purging technique. Stainless Steel World. May 2013
Danger of Corrosion when Welding Stainless Steel Food Safety Magazine Digest Nov 2014
Major Advances in Weld Purge Technology World Pipelines 2014
Latest developments in weld purging


Inflatable Tube and Pipe
Weld Purging System

For purging when pre and post
weld heating is required



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