KEVOS® MAKEOS · Maintenance
Coolant Tank Maintenance (Concentration, Correction, Make-Up Mix, Usage)
What is the coolant concentration from my refractometer reading, what do I add to correct it, what make-up mix keeps it on target, and how much concentrate will I use?
Maintenance plan for a water-mixed metalworking fluid sump: concentration from the refractometer reading and the product factor, the concentrate or water to add to bring it to target (as the refractometer concentration tool), the make-up mix strength that holds the target when water evaporates and mixed fluid is dragged out on chips and parts, the daily make-up volume, and concentrate use and cost per month.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Refractometer reading | °Brix | Reading on the refractometer scale. |
| Refractometer factor for the product | Refractometer factor of the coolant product (from its data sheet). | |
| Target concentration | % | Concentration the supplier recommends for the work. |
| Sump volume | L | Working volume of fluid in the sump. |
| Water evaporated per day | L/day | Water lost by evaporation each day (only water leaves). |
| Mixed fluid dragged out per day | L/day | Mixed fluid carried away on chips, parts and leaks each day. |
| Working days per month | Working days per month. | |
| Concentrate price | $/L | Price of the concentrate. |
| Accepted deviation from target | % | Plus-or-minus deviation from target you accept before correcting (as a share of the target). |
Method and formulas
- Concentration = reading × factor; correction to the target (as the refractometer concentration tool).
- Steady make-up strength c_m = target × drag-out ÷ (drag-out + evaporation), because only water evaporates.
- Daily make-up = drag-out + evaporation; concentrate per day = make-up × c_m; per month = per day × days.
- Example: 4 °Brix is 6.4%; add 2.5806 L of concentrate; top up with a 2.3333% mix, using 7.7 L of concentrate a month.
Limitations
- Uniform losses; tramp oil raises refractometer readings and must be removed first.
- Concentration correction assumes undiluted concentrate or clean water is added.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Correct a machine sump to its target concentration
- Set the make-up mix ratio
- Budget coolant concentrate use
Who it is for
- Machine operators
- Maintenance technicians
- Production supervisors
What you get
- Actual concentration and the correction to make
- Make-up mix strength and daily volume
- Concentrate use and cost per month
Interpreting the result
- Topping up with neat water lets the concentration fall with drag-out; with neat concentrate it climbs as water evaporates.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1176–1181. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
Open the Coolant Tank Maintenance (Concentration, Correction, Make-Up Mix, Usage) calculator
