BIZOMAT MAKEOS · Maintenance
Coolant Concentration from Refractometer
What is the coolant concentration from this refractometer reading, and what should be added to correct it?
Coolant concentration from a Brix refractometer reading and the coolant’s refractometer factor, and the volume of concentrate or water to add to reach the target.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Refractometer reading | °Brix | Reading from a clean, calibrated refractometer at the sump temperature. |
| Refractometer factor of the coolant | Factor from the coolant data sheet (concentration = Brix × factor). | |
| Target concentration | % | Concentration recommended by the coolant maker for this operation. |
| Sump volume | L | Current volume of coolant in the sump. |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Refractometer reading
- What it is
- The reading on the refractometer scale when a drop of the working coolant from the sump is placed on the prism.
- Units and format
- Enter a number in °Brix: °Brix. The form accepts 0 °Brix to 50 °Brix. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 4 °Brix as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Concentration is the reading times the factor, so it rises in direct proportion.
- Get it right
- Zero the instrument with clean water first and remove tramp oil from the sample; oil distorts the reading.
What this means: Refractometer factor of the coolant
- What it is
- The multiplier from the coolant maker’s data sheet that converts a Brix reading into concentration for that particular product.
- Units and format
- Enter a plain number with no unit. The form accepts 0.1 to 10. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 1.6 as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Each coolant product has its own factor; using another product’s factor gives the wrong concentration.
What this means: Target concentration
- What it is
- The concentration of concentrate in water you want in the sump, as recommended by the coolant maker for the operation.
- Units and format
- Enter a number in %: percent: the number is read as a percentage, so type 8 for 8 %. The form accepts 0.1% to 50%. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 7% as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Type the percentage itself (7 for 7 %), from the coolant maker’s recommendation.
What this means: Sump volume
- What it is
- The volume of coolant currently in the sump or tank, used to work out how much concentrate or water to add.
- Units and format
- Enter a number in L: litres. The form accepts 0.000001 L to 1000000 L. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 400 L as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- The amount to add rises in proportion to the sump volume.
- Get it right
- Use the volume actually in the sump now, not the tank’s full capacity.
Method and formulas
- Concentration = Brix reading × refractometer factor.
- Too weak: add concentrate x = V (target − actual) ÷ (100 − target).
- Too strong: add water x = V (actual − target) ÷ target.
- Example: 4 °Brix × 1.6 = 6.4%; add 2.5806 L of concentrate to reach 7%.
Limitations
- Tramp oil and contamination raise the reading; check against titration periodically.
- Assumes the added concentrate is undiluted.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check daily sump concentration
- Calculate a correction addition
- Keep coolant within the maker’s range
Who it is for
- Machine operators
- Maintenance technicians
- Coolant managers
What you get
- Actual concentration
- Difference from target
- Concentrate or water to add
Interpreting the result
- Add premixed coolant at the target concentration for routine top-ups; use corrections only to fix drift.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1176–1181. Topic reference; no source tables or recommended settings are reproduced.
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Open the Coolant Concentration from Refractometer calculator