The Validation Centre (TVC) Ltd

The Validation Centre (TVC) Ltd

News in Blog

Making Sense: O2 Sensors

July 14, 2021

O2 Sensor Types

For many years, the Welding industry has used simple handheld meters to measure the level of O2 in inert gas used for the back purging of pipes and vessels prior to and during welding. The cheapest and simplest sensor type had always been the Chemical Cell. However, in recent years new sensor types have become available which offer better accuracy, repeatability, and sensor life span. (more…)

Water Tank Manufacture with Flow Control using Forming Gas

December 3, 2020

Automated GTAW Water Tank Manufacture and Gas Wastage

TVC was approached by a company who manufacture Duplex water tanks and use a forming gas for back purging the tanks. As the welding process is automated GTAW, the operation process involves setting up a tank to purge whilst a pre-purged tank is being welded.

Prior to purchasing TVC Oxygen monitoring and flow control equipment, the initial purge was carried out by ensuring that the purge, at a high flow rate, was maintained for a set period of time. The drawback to this method was, however, that the time the tank was on purge could often exceed the nominal time required to fully purge the vessel and, therefore, wasted a large volume of gas. (more…)

Duplex Container Manufacturing with Robot Interface

October 22, 2020

In some industry sectors, it is commonplace to use welded duplex vessels for waste management. The vessels can be manufactured using robotic welding and need to be purged prior to commencing the welding process.

To ensure that the setup and robotic welding of the vessels work with maximum efficiency, TVC has included additional robot signalling on the Gas Purge Monitor (GPM) units together with a 3-Stage Purge Gas Flow Control System.


GPM and Audible/Visual Traffic Light Beacon


Wireless Remote O2 Sensor for Pipeline Welding fitted to Internal Line Up Clamp

October 15, 2020

Wireless Remote O2 Sensor for Pipeline Welding fitted to Internal Line Up Clamp

In the pipeline welding industry, it is commonplace to use an Internal Line Up Clamp (ILUC). This will align the two pipe sections using internal hydraulic or pneumatic rams so that external automatic welding equipment can be used to weld the root pass. When welding duplex or Inconel clad pipes, the ILUC will also have a purge dam fitted.

O2 Sensor

3D Model of Wireless Remote O2 Sensor


Purging Manual Tie-In Welds on Pipe Spools with Wireless Remote

October 8, 2020

Purging Manual Tie-In Welds on Pipe Spools with Wireless Remote

TVC was approached by an offshore oil and gas pipeline fabrication company to assist with purging manual tie-in welds on 1 Km duplex and Inconel clad pipe spools. The welding specification stated:

• the internal back purge had to be maintained for the root, as well as the hot pass
• the level had to be less than 50ppm

The client had previously been using an internal purge dam with an external purge O2 monitor; however, this was not a suitable solution because they had to test the O2 content through the open root gap. This meant that they were unable to monitor and verify the O2 levels as stated in the welding specification when closing the root pass and whilst welding the hot pass. Another issue was the time taken to purge the joint as they were supplying the purge gas from the open end of the pipe over 1 Km; even with an initial flow rate of 40 LPM, the preliminary purge took considerable time. (more…)

VE Day: WWII Innovations Pt. 2

May 12, 2020


Last time we took an in-depth look at Project PLUTO and the issues surrounding fuel supplies during WWII. In this post, we have investigated specific areas of Non-Destructive Testing and the innovations within them.



VE Day: WWII Innovations Pt. 1

May 7, 2020

VE Day

This week, 75 years ago, the Allies formally accepted the unconditional surrender of Nazi Germany’s armed forces.

As we approach the Bank Holiday here in the UK celebrating this special 75th anniversary of VE Day, we have investigated what industry technologies were discovered and/or developed during the Second World War.

Remembrance_Day (more…)