| Milliliters per minute (mL/min) | Fluid ounces per minute (fl oz/min) |
|---|---|
| 1 Milliliter per minute | 0.0351950797279 fl oz/min |
| 2 Milliliters per minute | 0.0703901594557 fl oz/min |
| 3 Milliliters per minute | 0.105585239184 fl oz/min |
| 4 Milliliters per minute | 0.140780318911 fl oz/min |
| 5 Milliliters per minute | 0.175975398639 fl oz/min |
| 10 Milliliters per minute | 0.351950797279 fl oz/min |
| 20 Milliliters per minute | 0.703901594557 fl oz/min |
| 25 Milliliters per minute | 0.879876993196 fl oz/min |
| 50 Milliliters per minute | 1.75975398639 fl oz/min |
| 100 Milliliters per minute | 3.51950797279 fl oz/min |
| Reference | Milliliters per minute (mL/min) | Fluid ounces per minute (fl oz/min) |
|---|---|---|
| A domestic shower | 9000 mL/min | 316.756 fl oz/min |
| A kitchen tap | 10000 mL/min | 351.951 fl oz/min |
| A garden hose | 15000 mL/min | 527.926 fl oz/min |
| The Amazon river | 1.254 × 1013 mL/min | 4.41346 × 1011 fl oz/min |
The millilitre per minute is a unit of volumetric flow rate equal to one millilitre passing a point every minute. Its symbol is mL/min. It is the working unit of clinical medicine and of analytical chemistry, two fields in which the quantity delivered matters far more than the speed of delivery.
Intravenous infusion is the clearest case. A drip is set in millilitres per hour for slow fluids and in millilitres per minute for fast ones, and an infusion pump is programmed with a rate and a volume. A litre of saline given over four hours runs at about four millilitres per minute; the same litre given rapidly in an emergency may run at a hundred.
Liquid chromatography works in the same range. A conventional analytical column is run at one millilitre per minute, a figure so standard that it appears as a default in almost every published method. Narrower columns run proportionally slower, and the flow must be held steady to within a fraction of a per cent, because the time at which a compound emerges depends on it.
Anaesthetic and oxygen delivery use the unit too, though there the fluid is a gas. Oxygen therapy is prescribed in litres per minute, and the small adjustments within that are made in hundreds of millilitres per minute. In each case the rate is a prescription, and the equipment exists to hold it constant.
Sixty millilitres per minute is one millilitre per second, so the conversion between the two is the same factor as between minutes and seconds. That relationship makes it easy to move between the fast and slow ends of the same equipment: a pump specified in millilitres per minute can be reasoned about in millilitres per second by dividing by sixty.
For everyday scale, a millilitre per minute would fill a teaspoon in five minutes and a cup in four hours. It is a rate slow enough that watching it is uninformative, which is why the instruments that use it display a totalised volume as well as a rate.
One millilitre per minute equals about 0.01667 millilitres per second, 60 millilitres per hour, or 0.001 litres per minute.
The fluid ounce per minute is a unit of volumetric flow rate equal to one imperial fluid ounce passing a point every minute. Its symbol is fl oz/min. At 28.413 millilitres to the ounce, a minute at this rate delivers a small glass, which places the unit among the deliberate, controlled flows of food, drink and light industry.
Beverage dispensing is its steadiest employer. A post-mix drinks tower is set so that each nozzle delivers a fixed number of fluid ounces per minute, and the ratio of syrup to carbonated water — commonly one to five — is maintained by matching the two rates. A coffee machine's brew rate, a beer line's pour rate and a juice dispenser's throughput are all quoted this way.
Small dosing and metering pumps in food processing carry the same units. Flavourings, colourings, brines and preservatives are injected into a product stream at so many fluid ounces per minute, and the ratio to the main flow is what determines the finished recipe. A pump that drifts by five per cent changes the taste of every package made that shift.
Cleaning and chemical injection follow the same pattern. A dairy or brewery cleaning system meters detergent and sanitiser into circulating water at a rate in fluid ounces per minute, chosen so that the concentration in the loop matches what the supplier specifies for the temperature and contact time being used.
Laboratory and pilot-plant work in Britain and the Commonwealth still meets the unit in older equipment and older standard methods. Rotameters graduated in fluid ounces per minute remain in service, and a technician reading one must remember whether the scale is imperial or American, since the two ounces differ by four per cent.
For orientation, 60 fluid ounces per minute is one fluid ounce per second, 35 fluid ounces per minute is about a litre per minute, and 160 fluid ounces make an imperial gallon. So a dispenser running at 32 fluid ounces per minute fills a gallon in five minutes exactly.
One fluid ounce per minute equals about 28.41 millilitres per minute, about 0.02841 litres per minute, or about 0.01667 fluid ounces per second.