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SMT Exhaust Vacuum Monitor

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#53587

SMT Exhaust Vacuum Monitor | 7 February, 2008

Does anyone use or have any simple wave/reflow oven exhaust monitors with a visual check (LED).

I was going to design something crude resembling a fan with an electric winding (electric motor of sorts)and a load (resistor maybe with a transistor if needed) attached to an LED.

I would need something that wouldn't activate the LED at low RPMs (due to heated air causing convected air flow) but would illuminate at higher RPMs signifying that the vacuum created suction is present.

If there aren't plug and play devices that are like this does anyone have any good sources/vendors that may have something close to the fan/winding assembly?

It essentially is a small windmill generator if that helps visualize what I need.

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#53588

SMT Exhaust Vacuum Monitor | 7 February, 2008

Here is another visual.

http://www.metacafe.com/watch/416435/computer_fan_generator/

Only issue with a PC fan is I'm positive that the blades will melt while enduring the heat of the reflow oven exhaust.

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#53589

SMT Exhaust Vacuum Monitor | 7 February, 2008

I would probably try to get my boss to spring for a digital anemometer (air velocity meter) and figure out what my velocity needed to be to get the specified airflow. Then just check it daily before production starts and when it starts to slow down, clean the pipe.

If you've had a failure and/or expect to have them them and want constant monitoring, you can get a pitot tube type gauge that's a lot cheaper but it still wouldn't activate an indicator light. I'm sure you could rig something like what you're doing but I don't know where you'd get a fan rated for that heat.

You could mount the fan further up the tube where it's cooler but it makes it that much more of a maintenance issue, which is why I'd avoid it altogether.

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#53601

SMT Exhaust Vacuum Monitor | 8 February, 2008

You can do what someone at heller mentioned to me to check if the exhaust is working properly. Take a baseball cap place it by the opening to the vent and if it wants to suck in the hat your good to go. Cost $12.00

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Reflow Oven

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