WHAT FLOW RATE CAUSES TURBULENCE?
Although little is published about the flow rates causing turbulence in MIG (and TIG) welding one technical paper used interesting methods to directly define turbulence in shielding gas flow. One was to measure the oxygen near the weld to define what flow created air mixing with the shielding gas stream. Other approaches were also utilized.
Need for Some Extra Gas to Purge Air Defined by Stauffer in 1982
In a 1982 Patent Stauffer defined the need for extra start gas in his shielding gas waste control device. He added a rather large starting gas storage volume element (item 112 in patent figure right) because his device also used relatively low pressure, less than the 25-psi needed to achieve choked flow. The patent states: "... air leaks back into the MIG gun and lines when welding is stopped. The air must be quickly purged and replaced with inert gas to produce high quality welds. Also, it is critical to displace the air at the weld zone of the work piece upon initiating the weld."
OUR PATENTED SOLUTION TO GAS WASTE IS INEXPENSIVE, MAINTAINS AUTOMATIC FLOW COMENSATION AND IMPROVES WELD START QUALITY
Our patented Gas Saving System solution (GSS) has no moving parts and is inexpensive. Most important, welders love the improved starts.
Yep, some fabricators understand and calculate how much shielding gas they are wasting. But a major precept of “Lean Manufacturing” states most waste is invisible. Must work to quantify. Sure fits shielding gas!
Our patented solution is straight forward and simple. It employs a custom extruded small ID, large OD gas delivery hose from flow control at the gas source cylinder of pipeline. That reduces the amount of shielding gas stored when welding stops.
To keep the peak flow from becoming excessively turbulent at each weld start it incorporates a “peak flow limiting” orifice. NOTE, it does NOT control the steady state flow only the peak flow. If welders are foolishly setting very high flows, it will limit flow to under ~90 CFH. But in that situation welders should be trained that anything over about 55 CFH is just pulling air into the shielding gas stream and making weld quality worse. The combination small ID hose and peak flow control orifice typically cut total gas use in half! That assumes leaks are monitored and fixed.
It’s simple to install. Just replace the existing gas hose from flow control at gas source to wire feeder or welder. That’s it! Set the proper flow and start welding.
EXAMPLE:
We have hundreds of users and many who have documented their savings results with careful measurement of up to 63%. However, this early customer experience defines not only the 40+% savings they found BUT most important, improved weld start quality.
This was a pipe weld repair application and as soon as the welding engineer and I installed the GSS and he was going to measure gas savings the welder said, “This is much better!” NOT in gas savings but weld start!
He was having many rejected repair welds after they were ultrasonically checked. He knew the cause was the high gas surge at the start. He would cut the wire close to the tip and keep the MIG gun high to give time for the audible gas blast to reduce. As can be seen he was facing a 3+ second problem where the flow was turbulent pulling in moisture laden air. After 6 months of use he said he was experiencing very few defects! The start quality sayings were at least as important to reduced gas waste! |