Myron L Litho-Kit - Manual (Page 4)

Because contaminants in water are often ionized,
conductivity has long been recognized as a good
overall indicator of water quality. Portable conductivity
instruments and/or in-line conductivity monitor/
controllers are normally included in industrial reverse
osmosis and deionization water treatment systems.
If the system in your plant did not include a Myron L
portable instrument, the instrument in your Litho-Kit ™
can be used to check:
1. System Efficiency
2. Tap Water Quality Fluctuations
Other models designed specifically for water
treatment equipment testing can be found in the
REPLACEMENTS/OPTIONS section of this Guide.
ACCESSORIES IN YOUR LITHO-KIT ™
Calibration solutions ensure continued instrument
accuracy. Information on the procedures and frequency
of recalibration will be found in your instrument
Operating Instructions booklet. The small bottles
included in the kit can be refilled with the 1 L/32 oz.
solutions found in REPLACEMENTS/OPTIONS.
The syringe included in your kit is the easiest way to take
a dampening solution sample. This is especially true
when the sample is drawn from the fountain pan (the
most representative source). Carefully transfer solution
directly into the meter's cell cup for testing. Make sure to
always rinse the syringe with clean water after use.
Using the thermometer to check dampening solution
temperature regularly during a run is important for
continued quality printing. Dampening solutions,
especially alcohol-free types are more viscous (therefore,
more effective) when chilled to 10-13º C/ 50-55°F.
Since it is normal for the temperature to increase slightly in
the fountain pan, it is preferable to check temperature there,
rather than in the recirculator. The temperature difference
between the recirculator and pan usually should not be
more than + 1 °C/2 °F. If the difference is greater, and pan
solution temperature is not within the ideal range, steps can
be taken to reduce the differential. These include insulating
solution supply and return lines and moving the recirculator.
For advice on ideal solution and how to maintain it, see
your local supplier.
RECOMMENDATIONS FOR USING YOUR
LITHO-KIT ™
PLOTTING A CONCENTRATION GRAPH
One of the most useful benefits your Litho-Kit™ can
provide is a solution concentration graph. After plotting
various mixtures of etch with your water, it will be very
easy to later check the strength of your dampening
solution on the press. Then, you can see which
concentration results in the best quality printing.
The following procedure can be accomplished using the
blank graph form at the end of this guide. This form may
be copied for future use.
1. Measure the conductivity and pH
of water normally used to make the
dampening solution. Fill a clean
3,8 L /1 gallon bottle with water.
2. Add 29,6 mL/1 oz. of fountain solution
concentrate. Remeasure both conductivity
and pH. Record these values.
3. Add another ounce (59,15 mL/2 oz. total) of
fountain solution concentrate and
remeasure both conductivity and pH.
Repeat this process (in 14,79 mL/1/2 oz.
additions, if preferred) until the amount
of fountain solution added exceeds the
manufacturer's recommendations.
4. Plot these values on the graph form
provided.
5. Make new charts when changing
brands of dampening solution, or tap
water quality changes more than
+ 50 microsiemens (micromhos).
ADDITIONAL RECOMMENDATIONS
1.
Discuss your printing requirements with your
chemical supplier to obtain the best dampening
solution for your local water and other conditions.
2. Carefully follow the manufacturer's mixing
instructions.
3. Run the recommended mixture of dampening
solution and monitor its printability. Communicate
this information back to the dampening solution
manufacturer.
4. Check dampening solutions regularly with your
Myron L instrument and thermometer. Paper
coating, ink bleed, and blanket or roller cleaners
can contaminate dampening solution. Take
temperature, pH and conductivity readings after
every 1-3 hours of press operation. Record these
readings in the press log book. Keep the solution
at the concentration you have found works best.