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  1. #1
    Join Date
    Jan 2011
    Location
    north texas
    Posts
    3

    Testing Fountain Solution Conductivity

    Please understand I have only been a pressman for six years. I have a question about fountain solution conductivity. We have an older Goss offset press and our water system is just as old. We use two different kinds of fountain solutions (Liquid Gold and Advantage 21) We switch when each barrel is empty. but we consistantly have a problem with our paper running dirty after 20,000 copies (collect) or on restart after a sudden stop.

    We primarily use a Myron L meter to read our conductivity. But it reads in PPM and not Micromhos. One foreman says run it at 1800PPM and the other has us run it at 1200ppm or less. the first foreman has no problems with dirty runs but they only run short straight runs. the other foreman has been reading a lot of the EPA information about conductivity and has decided that lower is better.

    What I am trying to find out is the difference between PPM and micromhos. I understand that the relationship between micromhos and PPM is just that micromhos = ppm x 1.5 A lot of the reading I have done online I have noticed that most printers read their conductivity in micromhos instead of PPM. Why is that? Is a micromho reading more accurate than PPM? Should we stop using the MyronL meter and use something else?

    I care about the quality of our product and want to understand conductivity better. If someone could point me in the right direction toward learning more about fountain solutions and conductivity I would be most appreciative

    Any advice or information will be appreciated.

    Thanks

    Mitch

  2. #2
    Join Date
    Jun 2009
    Location
    USA
    Posts
    14

    I wish I had much to give you on information but I had experience with Micromhos type Conductivity readers. As I understand it, Micromhos is more accurate and give the true value of conductivity.
    What type of water system do you use? closed system? It appears that perhaps the ink is being emulsified meaning it is too hot or too much Fountain solution. It has been 15 years since I did any test. I use an dosantron system to mix % of fountain solution and water. I just had to figure the % using a tester when it was first put in. I do know that according to the instructions of the Fountain Solution, it will say, to start out at (something like) 2 oz per gallon. But you may not have the system to know the ratio.

    Thats my two cents.. and hope you find an solution

  3. #3
    Join Date
    Oct 2008
    Location
    new york city
    Posts
    386

    i dont think that theres a conductivity meter out there, or a scale of measurement available, that will be of any use to you until you standardize your pressroom chemistry. Your various foremans need to get their collective heads together and decide on both a standardized product to use, along with a target reading thats in ageement with each other. Good luck on that one!!! Before there were fountain solution dosers i was a firm advocate of large batch mixing of fountain solution for all the presses to draw from. Assuming of course they were all presses of the same brand and type.
    Only until you get all parties on the same page with a product thats known to perform and in agreement on the formula will you begin to work towards any type of solution. This would be a good time to get your suppliers involved by having them send a tech rep over to help you sort out your issues. Unfortunately you're in a sticky situation because you're not in a position to initiate this.

  4. #4
    Join Date
    Jan 2011
    Location
    north texas
    Posts
    3

    Quote Originally Posted by cjwworld View Post
    As I understand it, Micromhos is more accurate and give the true value of conductivity.
    What type of water system do you use? closed system?
    Thanks for the reply. My main desire was to get information on the relatioinship between the PPM and Micromhos so I could understand more where everyone is coming from. As far as the water system is concerned, I am fairly sure it is a closed system (it recirculates out of a tank which is resupplied automatically from a mixer). I'm sure I will get the answer I need, I just need to keep searching - I was tryinig to take the easy way out by using the forum.

  5. #5
    Join Date
    Jan 2011
    Location
    north texas
    Posts
    3

    Quote Originally Posted by turbotom1052 View Post
    . Unfortunately you're in a sticky situation because you're not in a position to initiate this.
    ....and that's the truth. But you are right, until everyone agrees we'll continue to have difficulties and us underlings will have to deal with it.

  6. #6
    Join Date
    Oct 2009
    Location
    KARACHI PAKISTAN
    Posts
    356

    micro siemens per ohm is the unit for water conductivity and ppm is the unit for water hardness.... ppm is the American measuring unit for water hardness and dH is the German unit...

  7. #7
    Join Date
    Oct 2009
    Location
    KARACHI PAKISTAN
    Posts
    356

    The level of total hardness in water can be evaluated with commercial testing kits, which measure the concentrations of calcium and magnesium. Several scales are used to describe the hardness of water in different contexts. The hardness is indicated by a calculation where both calcium and magnesium values are reported as mg/L (ppm) (Ca x 2.5) + (Mg x 4.12)= Hardness in mg/L

    * Parts per million (ppm)
    Usually defined as one milligram of calcium carbonate (CaCO3) per liter of water (the definition used below).[16]
    * Grains per Gallon (gpg)
    Defined as 1 grain (64.8 mg) of calcium carbonate per U.S. gallon (3.79 litres), or 17.118 ppm
    * mmol/L (millimoles per litre)
    One millimole of calcium (either Ca2+ or CaCO3) per litre of water corresponds to a hardness of 100.09 ppm or 5.608 dGH, since the molar mass of calcium carbonate is 100.09 g/mol.
    * Degrees of General Hardness (dGH)
    One degree of General Hardness is defined as 10 milligrams of calcium oxide per litre of water, which is the same as one German degree (17.848 ppm).
    * Various alternative "degrees":
    o Clark degrees (°Clark)/English degrees (°e or e)
    One degree Clark is defined as one grain (64.8 mg) of calcium carbonate per Imperial gallon (4.55 litres) of water, equivalent to 14.254 ppm.
    o German degrees (Deutsche Härte, °dH or dH)
    One degree German is defined as 10 milligrams of calcium oxide per litre of water. This is equivalent to 17.848 milligrams of calcium carbonate per litre of water, or 17.848 ppm.
    o French degrees (°F or f) (letter written in lower-case to avoid confusion with degree Fahrenheit — not always adhered to)
    One degree French is defined as 10 milligrams of calcium carbonate per litre of water, equivalent to 10 ppm.
    o American degrees
    One degree American is defined as one milligram of calcium carbonate per litre of water, equivalent to 1 ppm.

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  9. #8
    Join Date
    May 2011
    Location
    California
    Posts
    6

    PPM vs Micromho conversion

    Quote Originally Posted by mitchcooley View Post
    What I am trying to find out is the difference between PPM and micromhos. I understand that the relationship between micromhos and PPM is just that micromhos = ppm x 1.5 A lot of the reading I have done online I have noticed that most printers read their conductivity in micromhos instead of PPM. Why is that? Is a micromho reading more accurate than PPM? Should we stop using the MyronL meter and use something else?

    I care about the quality of our product and want to understand conductivity better. If someone could point me in the right direction toward learning more about fountain solutions and conductivity I would be most appreciative

    Any advice or information will be appreciated.

    Thanks

    Mitch

    Hi Mitch,

    I have posted a link below with some info about Conductivity to TDS conversions. The TDS to Conductivity correlation is non-linear and no single multiplier can determine the relationship. Conductivity (micromhos) gives the conductance value of the water. TDS (ppm) gives you the number of total dissolved solids in the water based on salt type.

    Link to Conversion Article: http://blog.myronlmeters.com/archives/5

    We have Myron L meters available that measure in micromhos. You can select the one that measures your range. Take a look here: http://www.myronlmeters.com/category-s/62.htm

    We have seen that most of our other printing customers use conductivity (micromhos) to measure their fountain solutions. It is not that micromhos is more accurate, but just a different type of indicator (more universally recognized).

    Let me know if this helps or if you have any other questions. Email me at technicalsupport@myronlmeters.com

    Best Regards,
    Jim Rutan
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