Temperature Measurement - Seal Ribbon on Vacuum Implulse Sealer

Hello Dennis

First i will assume that you are not the manufacturer of the impulse vacuum sealer.

If you are sure that your seal problem relates to voltage fluctuation and not some other problem such as uniform pressure of sealing components then you need to regulate the voltage.

This will eliminate the need of trying to measure the temperature so all you will have to deal with is the impulse seal time.

Here are a couple of sites with information about regulators. I would also contact the manufacturer of the machine you are using to find out if they have a regulator solution that you can easily incorporate.

http://www.globalspec.com/reference/11060/Technical-Article-Double-Conversion-Electronic-Voltage-Regulator-Operation

http://www.tsipower.com/Automatic-voltage-regulator-precision-ac.htm

The prices have come down and technology has improved so you should be able to find a regulator at a decent price that will perform to your requirements.

Hope this helps and good luck to you.

Regards

Jeff

Assuming you can not attach thermocouples to the heating ribbon, or use an infrared pyrometer, the next best thing might be to create a dummy load e.g. a thermocouple instrumented representation of the part you are attempting to seal. If voltage fluctuations are responsible for variable results, it should show in your data. You then have the options of either providing temperature regulation, or showing your data to the manufacturer of the sealer and requesting assistance.

Pardon me but I think you'll still have problems even if you were able to put a thermocouple in your sealing ribbon. Yes, you'll probably reduce the occurrence but you will definitely not eliminate it. The proper solution will be to regulate or control your voltage fluctuations.

So I'm with snygolfgs on this (along with a GA from me). Solve your voltage fluctuations and you'll only have to deal with the sealing time.

In our factory, we use sealing jaws instead of ribbons. These are steel bars with cartridge heaters and thermocouples inserted in them. The thickness of the bars make this possible. Since your machines use sealing ribbons, putting thermocouples is going to be difficult if not impossible.

regards,

Vulcan

Thanks for all your comments. Actually, we have an AVR already that were installed in the system to address the voltage flactuation. However, when we conducted a PQA on the power source, we have a lot of voltage spikes observed for as low as 10volts within a second. Does this spikes being corrected by an AVR? On the data also, we found out that %THD on current was at 87.4% and 2% for the %THD on voltage. Does this data affects the heating temperature of the seal ribbon? or the seal integrity? What equipments does best suit to address both voltge spikes and the %THD (if it really affects the sealing) for our impulse sealers? Will a UPS adrress these?

Looking for forward for your inputs and recommendations.

Regards,

Dennis

Hello Dennis

The THD (total harmonic distortion...in case anybody's reading) should not effect a resistive load such as your ribbon sealer so shouldn't influence your seal integrity.

When you state that you have voltage drops as low as 10volts in one second, do you mean 10volts below nominal voltage or the voltage drops to 10 volts?

Most good AVRs will handle voltage fluctuations of +/- 20 to 25% of normal input voltage. I like the newer PWM type AVRs because they switch much faster without any dead time.

A really good line-interactive UPS will regulate your voltage about the same as an AVR, +/- 20 to 25% but has the added ability to switch to battery with-in 15ms if the voltage drops below its regulation range or drops to '0'. This might help your situation but it probably won't be very cheap.

Also, wildly fluctuating input voltages may also adversely effect your seal timer circuit.

Where are you located? Is this something you've been fighting with for a long time or just recently occuring?

Jeff

Hi Jeff,

Really appreciate your quick response.

Thank you, at least for now, we are free of the effect of high %THD... thus, eliminating that factor. Actually, we have a plan to have a seperate generator set just for the seal ribbon, for us to address the %THD, voltage flactuations and spikes.... BUT, still looking into a much simplier solutions...

On the voltage spikes, i have attached the graph monitor of the volteage that we have taken. It shows here that it drastically drops from 432 to 422 injust a second and back again to 431...

We are int he Philippines and thes problem occured early last year...

Thank you all. I really found this site very helpful.

Regards,

Dennis

Voltage transients, spikes, dropouts, fluctuations, whatever you call them are best eliminated even if they don't seem to be causing problems.

I once recommended a company install an AVR on one of their equipment since they couldn't or didn't want to solve their voltage fluctuations. Later they called to say that it didn't help much. To my dismay they had gone and bought a motorized AVR. My fault I guess since I didn't go a step further and suggest what type to purchase.

One possible reason for your voltage fluctuation is a motor or device that consumes a lot of power when it starts (since your voltage drops - not a spike by the way). One other possible reason is a bad connection.

If eliminating the voltage fluctuations doesn't solve your problems, it still isn't a bad idea. For all you know, it's causing other problems that you're not aware of.

regards,

Vulcan

Hello Dennis,

Sometimes the solutions aren't as easy as we would like. Other than power regulation, the dedicated power source you stated would probably make a big difference with the quality of the seal of your packages.

As Vulcan said, if you are using a motorized AVR, that may not be the best solution as they are slower to react to voltage spikes or drops. A PWM AVR would be much better for your situation.

Vulcan is there in the Philippines with you so I'm sure would understand your power situation better than I so I would give his comments extra credence as they are correct. There is probably something in your facility nearby or a part of this machine that is causing your sudden voltage drops. Also, as was stated, check all connections to make sure nothing is loose or corroded.

Also, make sure that you are not experiencing changes in the quality or thickness of the packaging material that you are using. Don't be afraid to check and reject rolls of material that does not conform to your specifications. We would sometimes receive rolls of material that would vary in thickness on the same roll and this would cause seal problems. After we started rejecting large quantities of film from the manufacturer for out-of-spec variences, they began producing a more consistant product that also reduced our sealing problems. Just something to consider.

I'm glad that you found this site useful. Please keep in touch and let us know how your situation turns out and what worked to correct the errors you are experiencing as this may also help others who read this with a similar situation.

Kindest Regards,

Jeff