Metal shops all over the world use Dosatron to dispense metalworking fluids because the volumetric proportioning principle controls exactly how much fluid is used — none is wasted, and none is left to guesswork. Some operations have cut chemical, energy and maintenance spend by as much as $100,000 a year after switching from manual mixing to a Dosatron fluid-management system.
A Dosatron unit is a positive-displacement, water-driven metering pump. Water entering the pump drives a piston or diaphragm motor; each motor cycle displaces a fixed, adjustable charge of concentrate through a dosing piston into the water stream. Because the concentrate charge is indexed to the volume of water passing through the pump — not to line pressure or instantaneous flow rate — the delivered ratio holds constant across the pump's whole operating range:
V_concentrate = D × V_water → C_out = D × C_stock
A 10% dosing setting, for example, delivers a solution of 10 parts concentrated product to 100 parts water. In absolute terms this works out to 9.09% (10 ⁄ 110) — a distinction that matters when a chemical supplier's data sheet specifies an absolute percentage rather than a mixing ratio, and one worth checking before you select a model.
Metalworking fluid concentrates are typically prepared in one of three ways. Only one of them holds a fixed ratio independent of pressure, flow, and operator variability.
Method | How it doses | Where it fails in a metal shop |
Manual mixing | Operator measures concentrate by volume or by eye, adds to water in a bucket or sump | Measurement error varies by operator and shift; mixing order is often reversed (water into concentrate instead of concentrate into water), producing an unstable emulsion instead of a proper oil-in-water mix |
Venturi / eductor injector | Pressure differential across a constriction draws concentrate into the water stream | Ratio is a function of inlet pressure and back-pressure — both of which vary as other machines draw water, as hose length and fluid viscosity change, and as concentrate viscosity shifts with workshop temperature. There is no feedback to the operator when the ratio drifts |
Dosatron proportional injector | Positive-displacement piston/diaphragm motor driven by water flow; concentrate charge indexed to water volume, not pressure | Ratio holds constant across the flow range; no electricity, no controller, no operator measurement step; self-priming to 4 m |
Application | Typical chemistry dosed | Why proportional dosing matters here |
Cutting & stamping | Soluble-oil, semi-synthetic or synthetic cutting/stamping emulsions | Concentration directly sets tool life, chip evacuation and surface finish at the cutting or blanking edge |
Grinding | Semi-synthetic and synthetic grinding coolants | High heat load at the wheel-workpiece interface demands tight, repeatable concentration control |
Coolant systems | Central sump fill and top-up stations feeding one or several machines | Central stations must hold ratio even as simultaneous demand from multiple machines varies total flow |
Drawing / forming | Drawing and stamping lubricants, including higher-viscosity concentrates | Deep-draw and forming operations are especially sensitive to under-lubrication and galling |
Vibratory finishing (vibro-abrasion) | Finishing compounds and rust-inhibitor slurries for mass-finishing bowls and tubs | Compound starvation causes inconsistent finish; over-dosing wastes compound on every cycle |
Parts washing / industrial cleaning | Alkaline or acidic industrial cleaners and degreasers | Under- or over-dosing directly affects cleaning efficacy and rinse-stage chemical carry-over |
Die casting (poteying / mold release) | Release-agent and lubricant emulsions metered to the shot-cycle water line | Consistent release-agent film is required for repeatable part quality and die life |
Metalworking fluid — soluble-oil emulsion, semi-synthetic, or fully synthetic — has to cool the tool and workpiece, lubricate the cutting or forming action, flush away chips, and protect machined surfaces from corrosion, all at once. Every one of those functions depends on the fluid being mixed to the concentration its manufacturer specified.
A Dosatron installed on the water supply line feeding the sump or a central mixing station draws a fixed proportion of concentrate and injects it directly into the water flow as it fills — automatically, without an operator measuring anything or a separate concentrate-addition step. Because the ratio is set by the pump's stroke volume rather than by pressure or flow rate, the same setting delivers the same concentration whether the sump fills quickly or slowly.
Dosatron's own metal-processing application guidance flags a detail that is easy to miss on the shop floor: the initial %Brix reading from a refractometer is not the same as the volumetric percentage set on the pump. To confirm actual concentration, either calibrate the refractometer to the specific fluid or apply the equivalence curve published in the concentrate manufacturer's technical data sheet — most suppliers publish this curve at a reference temperature (commonly 20°C).
Pump selection is driven first by the fill-rate/flow requirement, then by the dosing rate the chemistry calls for.
Industrial Plumbing Kits (IPK) bundle everything needed to install and protect a Dosatron injector (sold separately) on the water supply line:
Kit | Matched to |
IPK34-3GPM | D07RE |
IPK34-14GPM | D14MZ |
IPK34-9GPM | D14MZ520 |
Each kit includes ball valves (to open and close the line), a 200-mesh filter (stops large particles), a pressure regulator with gauge, a flow restrictor (prevents excessive flow), a check valve, unions (for easy injector removal), a roll of Teflon® tape, fittings and an instruction card.