Own brand · Manufactured by MJS Purge Systems

Spanweld™

MJS temporary pipe-sealing and monitoring systems remove oxygen from inside the pipe during welding — delivering stronger, cleaner, void-free welds while cutting inert gas use and cost.

Why purge?

Remove the oxygen. Perfect the weld.

Oxygen inside the pipe oxidises the hot weld, causing discolouration, “sugaring” and corrosion that weaken the joint and trap contaminants. MJS systems displace that oxygen with inert gas so every internal weld comes out bright, smooth and void-free — essential for food, pharma and hygienic process lines, stainless steel pipework and nuclear industries.

By sealing only the weld zone, MJS uses a fraction of the inert gas of traditional full-length purging — saving money and reducing environmental impact.

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Inflatable pipe purge system — argon weld purge diagram

What oxygen does to a weld root

When stainless steel, duplex or titanium is heated past its critical temperature, any oxygen still present in the pipe reacts with the hot metal. The result is an oxide layer on the inside of the joint: discoloured at best, and at worst the rough, crystalline surface welders call “sugaring”.

That layer is not cosmetic. It removes chromium from the surface, destroys the corrosion resistance the alloy was specified for, and creates crevices where product, bacteria and cleaning chemicals collect. In hygienic and high-purity systems it is a rejection.

The traditional answer, and its cost

The conventional fix is to flood the entire pipe run with argon and wait. On a long spool that means a very large volume of gas, a long wait before striking an arc, and repeat purges every time the line is broken into.

The MJS approach

MJS purge systems seal only the weld zone. Two inflatable dams form a short chamber either side of the joint, inert gas displaces the oxygen inside it, and an oxygen monitor confirms when the atmosphere is ready. Less gas, less waiting, and a measurable, repeatable result you can certify.

Weld Purging, Engineered

A complete range of temporary pipe-sealing and monitoring products, proven on job sites and production lines worldwide.

Double Bag Inflatable Pipe Purge System | 2″–48″

Standard Purge

2″ – 48″

Tandem inflatable dam system for fast, low-volume purging of medium to large bore pipe, with integrated inert gas hose.

Standard Purge HR

Heat resistant

Heath resistent version for pre-heat and elevated temperature welding, protecting the dams and holding purge integrity.

Rapid Purge

8″ – 80″

Accelerated purging system that reaches low oxygen weld conditions faster, reducing downtime between joints,

Rapid Purge HR

Heat resistant

Heath resistent version of Rapid Purge for accelerated purging in pre heat and elevated temperature welding

Handy Purge 100 Monitor

Oxygen monitor

Self calibrating weld purge monitor measuring oxygen down to ppm levels for repeatable, certifiable weld quality.

Frequently Asked Questions

Weld purging, answered

How low does oxygen need to go?

It depends on the material and the specification. Many stainless applications target below 0.1% (1000ppm); titanium and high-purity work often calls for far lower. The Handy Purge 100 measures to 0.01%, so you can weld against a number rather than a guess.

Which system suits my pipe size?

The Double Bag Purge System covers 2″ to 48″ and handles around 90% of traditional purge applications. Above roughly 8″, Rapid Purge is usually the faster option, covering 8″ to 80″ with a thru-bore design that cuts purge volume dramatically.

What if the pipe is pre-heated?

Both families have a heat resistant variant. Standard Purge HT is jacketed for 350°C continuous and 500°C short-term; Rapid Purge HT is rated to 250°C.

Are the systems reusable?

Yes. The dams deflate and withdraw after each joint, and friction-free coatings let them move through bends and elbows to the next weld.

Do I still need to monitor oxygen?

Monitoring is what turns a purge into evidence. Without it you are estimating; with it you have a reading you can record against the joint.

Manufacturer

MJS Purge Systems

MJS Purge Systems Ltd is a UK designer and manufacturer of patented pipe purge systems, pipe stoppers, inflatable pipeline sealing products and oxygen monitors for welding, construction and industrial applications.

The business began in 1998, when Martyn and Julie Smith started making air bags and purge systems from their double garage in Leicester. From those early beginnings, MJS grew by working closely with customers, developing practical solutions to real site challenges and building a strong reputation for quality, reliability and innovation.

Over the years, MJS has become known for designing products that improve safety, reduce downtime and make pipe preparation and welding more efficient. A key part of that success has been listening to customers and turning real-world requirements into specialist products that deliver clear performance benefits.

In 2024, following the well-earned retirement of Martyn and Julie Smith, MJS Purge Systems Ltd was established to take the company forward. The business moved to a new factory in Peterlee, where a new team was trained to meet growing production demand and new systems were introduced to support future development.

We hold the patents and we manufacture the products ourselves.

mjspurgesystems.com

2003Patented purge technology

PPMO₂ monitoring accuracy

GlobalDistribution network

Purge Welding Products

Purge dams, monitors, tape

Spanstop™

Inflatable & mechanical plugs

Spanweld · Spanstop

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Custom-built systems are also available to meet specialist customer requirements.

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