In some industry sectors, it is commonplace to use welded duplex vessels for waste management. Any vessels manufactured using robotic welding need to be purged prior to commencing the welding process.
To ensure the setup and robotic welding of the vessels works 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.
Pre-programmed Limits
When the vessel has been set up on the welding jig in the robot cell, the GPM gas sample hose is connected to the vessel. The start button on the GPM is pressed and the Stage 1 gas flow solenoid is opened by the GPM providing a high purge gas flow into the vessel. The GPM has pre-programmed high and low alarm limits. When values are 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 give a ready-to-weld signal to the robot controller and the robot will automatically start the welding process.
Robotic Control
The GPM continually monitors the O2 levels in the vessel during welding. If the O2 level should rise above the low limit threshold, a signal is sent 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 restart.
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. Thus providing simple and efficient control of your welding purge process. If you have an application that requires automated purge control, contact us to discuss your requirements.