Are you familiar with orbital welding? When using this technique, the welding tool undergoes a rotation of 360˚ around a workpiece that’s static, such as a pipe.
Purging is an indispensable aspect of this technique, as it involves oxygen evacuation from pipes and tanks. It impedes oxygen from affecting the weld by reducing its quality and corrosion resistance.
Purge plugs are essential for obtaining the best possible welds. These are made of top-notch plastic resisting high temperatures and silicone rings.
Such plugs are placed on one side of the tube, whereas the exhaust is put on the other side. We hope the guide below explains everything you need to know about this topic.
These products are used for welding connections by allowing users to spin the workpiece while keeping a consistent purge. They feature two seal grooves to hold silicone foam rings in place.
Purging is of the utmost importance in orbital welding, referring to the removal of oxygen from the inside of pipes before the process begins. Argon shielding gas is usually used in the course of the process. Click here to learn more about the applications and properties of shielding gases.
Welders trying to perform a weld with no purging face problems because of the presence of oxygen. If oxygen is not removed, there’s a high risk of imperfections and discolorations that affect the weld’s integrity. This oxidation process is also known as sugaring, causing a multitude of problems in different industries.
In addition, oxidation is especially damaging in the piping industry, as it encourages bacteria growth in the interior of welded pipes, through which the product is flowing. Purging is also helpful in preventing the weld from sinking by keeping pipe pressure optimal.
There is a wide assortment of purge products that facilitate orbital welding. For example, purge plugs for pipes come with various features and are available in custom sizes. They have a silicon rubber bladder to enable heat resistance, a wing nut for achieving expansion inside tubes, and a hinged design that allows fast setup.
Furthermore, purge plugs are also armed with rapid disconnect for purge gas and a gas diffuser for an even gas distribution. The largest number of TechSouth purge plugs are constructed properly and priced reasonably. In contrast, stainless steel purge caps are armed with a silicon disc for a positive seal and a stainless diffuser for creating soft flow.
Purging for pipe welds is useful for creating the desired weld environment while welding corrosion-resistant materials like titanium, stainless steel, etc. In the course of welding, the heated seam is susceptible to oxidizing unless it’s properly protected.
Therefore, oxidation should be ideally prevented in order not to be treated later. Purging equipment is hence necessary to make sure the process is completed successfully.
Purge wands are essential tools for rapid aligning of sanitary ferrules of different sizes and types. There’s an aluminum backplate used for attaching a tool called an oxygen analyzer. These devices use an oxygen sensor that measures oxygen concentrations, which range between 0.05 % and 100%.
Weld purging requires welders to follow some safety tips to stay safe while performing this process. They must be aware of the hazards of argon and nitrogen gas, as both are colorless, tasteless, and odorless, hence impossible to be detected without using proper equipment. The asphyxiate nature of these gases makes people exposed to them lose their consciousness in less than a minute.
Brain damage, on the other hand, can take place within three minutes, while death is likely to occur in less than five minutes. Oxygen deprivation in a period longer than ten minutes minimizes the chances of survival. Normally, argon and nitrogen hazards are emphasized when working in enclosed spaces like pipes. See this URL, https://www.livescience.com/29023-argon.html, to discover some useful facts about argon.
Argon is much heavier than air, meaning it settles close to the bottom, whereas nitrogen is lighter and settles near the top. Both argon and nitrogen create pockets, which turn into a threat if they are disturbed by workers’ movements. Workers aren’t advised to enter pipes while a purge is ongoing.
Moreover, equipment inspections should be conducted prior to every purge, including all gear like purge dams and bladders, gas hose lines, and gas flow regulators. A tear or hole in the gas hose line is a high risk for a gas leak, as gas will leak into the work area, not flowing into the purge chamber. This not only results in the use of more gas but also nitrogen and argon buildup.
Another thing to check is the gas flow regulators in terms of frozen meters and cracks. If the regulator is broken, the amount of used nitrogen and argon will increase. A stable chamber is only feasible when there is a controlled gas flow. When the flow rate is high, there could be a disturbance in the vessel, which creates an unstable environment.
Dams and bladders should be inspected for punctures and tears. If a dam or a bladder is damaged, a stable environment cannot be achieved. Each equipment piece is specific regarding use instructions, meaning it requires controlled gas flow to function properly.
Workers should also follow some of the best practices for confined space entry. These spaces shouldn’t be entered without having a permit. Such permits are only supposed to be issued to employees who have the proper training for working in confined areas. You should be cautious about the procedure and timing for exiting the space.
Prior to entry, any physical hazards should be identified, such as unstable footing. Before entering and while inside, workers must monitor oxygen content and toxicity. It’s vital to keep in touch with the supervisor via two-way radio or phone for your own safety. The supervisor can order evacuation and rescue in case of a present hazard.
Purge plugs are crucial in orbital welding. They are small but effective!
Purge plugs are crucial in orbital welding. They are small but effective!