The Validation Centre (TVC) Ltd

The Validation Centre (TVC) Ltd

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

When the vessel has been set up on the welding jig in the robot cell, the GPM unit sample hose is connected to the vessel and the start button is pressed. On pressing the start button, the Stage 1 gas flow solenoid is opened by the GPM providing a high purge gas flow into the vessel. The GPM has a pre-programmed high and low alarm limit so when above the high limit, the high flow solenoid is opened and the red warning light illuminates. As the monitored O2 level drops below the high limit, the traffic light warning system will turn yellow and the mid-flow solenoid will be opened reducing the purge gas flow.

When the monitored O2 level drops below the low alarm value, the traffic light warning system will turn green and the low flow solenoid is opened reducing the purge gas flow to a level that is suitable for the robotic Welding of the vessel. A ‘dwell time’ can be programmed on the GPM to allow the O2 level to stabilise, the GPM will then give a ready-to-weld signal to the robot controller and the robot will automatically start the welding process.

The GPM will continually monitor the O2 levels in the vessel during welding and if the O2 level should rise above the low limit threshold, the GPM will send a signal to the robot controller to stop the welding process. The mid-flow solenoid will also be opened to increase the purge gas flow until the O2 level drops back below the low limit alarm threshold. The GPM will again send the ready-to-weld signal to the robot controller and welding can re-start.

The 3-Stage Gas Flow Control System, traffic light audio/visual warning beacon and robot/PLC output signalling interface are all standard options on the GPM unit. The Standard GPM unit can be interfaced with any robotic or PLC-controlled automated welding processes providing simple and efficient control of your welding purge process. If you have an application that requires automated purge control, then please contact us to discuss your requirements.