How to evaluate alcohol content in font solution?

[Tarun Chopra]

Hi,

Whenever fresh font is prepared the amount of alcohol can be verified with things like "alcoholometers" hydrometers without any additives like font solutions etc and the readings are very accurate, we can accurately estimate the amount of alcohol in water and then add font solution to specifications.

The problem which I am facing is the next day... when the font level in the chiller tank falls and when fresh additive is added how to verify the alcohol content in contaminated font solution? The hydrometer actually pops out completely?

I am being told by press operators that they have to add alcohol without measurement to avoid scumming during week days!!!

How do auto-dosage systems work? Do they keep on increasing alcohol dosage to avoid scumming during week days top-ups, is there a rule to this practice?

Thanks
Tarun Chopra

[spider]

I'll try and make it as simple as possible when you use alcohol with the font solution. your alcohol will attack the Font solution
when this happens the electric charge, decreases for your Font solution which gives you a low reading for your font solution
and then you will think you have to increase your solution in other words if you don't watch what you doing you will be caught up in a big circle. putting in alcohol then font and then more alcohol and so on

During the week when the press gets hot you will have to increase your alcohol depending on the temperatures

Auto-dosing systems for your alcohol use a hydrology and should keep it to the setting required around 5% or more,

I have found by keeping the font solution set correctly by taking a reading from where it enters the main tank and not from the tank itself.
And then tried to keep the Alcohol in the tank to 5%
And not from the same place.
I hope this is what you're looking for

[jbeniston]

In automatic systems "contaminated" dampening fluid returning from the press is flitered in the main tank. Some filtration systems such as "clean flow" remove almost all contaminants. The fluid is then passed through a system which, if you're using alcohol, checks the specific gravity, comparing it to a pre set value. If necessary the level of the float (hydrometer) will cause a solenoid valve to be opened, allowing alcohol to be injected into the fluid. The float will change level with the increase in alcohol and cause the alcohol flow to be switched off. Similar events take place to introduce additives into the fluid, as the system either measures pH or conductivity or demands the addition of "raw" water,
As the fluid is circulated to the press units and back to the tank, the dampening fluid is consumed, and the tank automatically maintains the pre set levels of alcohol, fountain concentrates, and water.
The press operator or the designated maintenance guy regularly check the contamination levels, either visually or by the change in conductivity and schedule the tank to be dumped, cleaned and refilled with fresh stuff.
Hope this helps a bit.

[RGPW17100]

Depending on how high tech your system is will depend on the accuracy of the alcohol in the fountain solution. Our chiller has a built in conductance meter and that is what we use to determine how much alcohol we need. As mentioned earlier by adding alcohol the conductance will go down. We maintain between 1100 and 1500 u mhos. When the conductance exceeds that is when we either have to start turning the water up or start scumming. Seems to me when using just a hydrometer you also have to take temperature into consideration. A 5 percent solution will be different at 70 degrees then it will at 65 degrees.

[lilgap84]

For new fountain solution, you could use the conductivity as a guide. However, as you print, the fountain solution will be contaminated.
The correct way that i have learned is to use an aerometer to measure the percentage of alcohol content.
Try asking your press chemical supplier, some carries them.

Jamie Choot

[Dan Roll]

Why are you using alcohol at all?

[Cornishpastythighs]

If you can, try and get off of Alcohol. Use a 2 part Fountain Solution( Etch and Alcohol sub) You can then measure your chemistry using Conductivity and a Refractometer to measure % of Alcohol sub. If you remove Alcohol from your pressroom you must ensure your press rollers are in good condition with correct Durometer specs, Rollers settings are checked regularly, correct printing squeezes and good dampening filtration and always follow the 3 golden rules, Minimum ink, Minimum water, Minimum pressure for good print. Good luck

[Tarun Chopra]

Thanks for all the inputs.

The reason for not using alcohol replacement solutions is that its very aggressive on thermal plates and we are getting strange problems running them including run length issues.

The problem which we are facing is to evaluate the content of alcohol in font solution during the week when the chiller is topped up and fresh font is not prepared.

Due to contamination of the font solution we are unable to accurately evaluate the alcohol content in the font solution because of which the press operator has to guess the amount of alcohol to be added during the week without any measurement.

Is there a way to identify alcohol content after font solution is contaminated using any measurement device?

Thanks
Tarun Chopra

[lilgap84]

might be the thing you are looking for.
http://www.boettcher.de/PDF-Dateien-...meter-engl.pdf

[Tarun Chopra]

Hi,

Yes, but this does not work well when the font solution is contaminated. This shows very strange readings the entire thing pops out to zero percent due to contamination of font solution !!!

Thanks
Tarun Chopra