Hi, I have a problem with manufacturing brass LPG gas jets... These jets have a hole diameter of 60microns or about 2½ thousandths of an inch, they are drilled by a tiny drill!!
These jets are used in a handheld heating item for high volume sale.
The Problem: At present the jets are drilled and finished to give a air flow reading which shows they are flowing the correct amount of gas at a set pressure. Unfortunately, after being assembled into the item and only at the final testing stage 30% of the items fails final checking for correct heating characteristics... This is unacceptable!
I have designed an accurate flow measuring instrument which has partially solved the problem but secondary effects now need to be analysed.
Because the jet flows gas into a venturi of accurate dimensions to give an exact gas - air mix ratio, I am sure that its not just the flow rate that needs testing, we need to measure the shape of the gas plume from the jet outlet...
The gas plume might be off to one side or possibly of a turbulent nature which may effect the gas - air mix ratio...
What's Needed: I believe that if we could flow a gas which is visible through the jet at the same time as measuring the flow the operator could check that the gas plume was not offset and was satisfactory....
So how would I make the tiny gas flow visible?
On larger jets I have designed an array of thermisters which when hit by the gas flow show a change in resistance and can be displayed... BUT as these jets only flow about 50cc per minute this is not possible...
Is there a gas that can be used which is visible to the human eye maybe under certain lighting conditions that could be used??
Or have you any other way that could be investigated?
John.