Conversion from 50 Cubic millimeters per hour to Cubic centimeters per minute

Information about the Cubic millimeter per hour (mm³/hour)

The cubic millimetre per hour is a unit of volumetric flow rate equal to one cubic millimetre passing a point every hour. Its symbol is mm³/h. It is one of the smallest flow rates in ordinary use: a full hour delivers a volume the size of a grain of coarse salt, so it belongs to processes measured in days rather than minutes.

Corrosion is described in these terms whenever the loss is treated as a volume rather than a depth. A steel surface corroding at 0.1 millimetres a year loses, over a square centimetre, roughly one cubic millimetre a year — and the hourly rate that produces it is a ten-thousandth of that. Cathodic-protection engineers work with such numbers because the whole point of the discipline is to make a rate small enough to ignore for decades.

Permeation and leakage testing lives here too. A sealed package, a fuel line or a medical device is tested for how much fluid crosses its wall, and the answer is often a few cubic millimetres per hour or less. A leak too small to see over a working day becomes, at this rate, a measurable volume after a month in a heated test chamber.

Slow drug delivery uses the unit directly. An implanted osmotic pump may release a few cubic millimetres of solution per hour for weeks, and an intrathecal pump can be programmed in fractions of one. Because the reservoir holds only a few millilitres, the hourly rate determines how long the implant lasts before it must be refilled.

Botany borrows it for sap and exudates. Xylem flow in a single small vessel, latex from a tapped rubber tree between collections, and phloem exudate sampled from an aphid stylet are all of this order, and researchers report them per hour because the sampling period is measured in hours.

The scale is worth stating plainly. A litre is a million cubic millimetres, so a flow of one cubic millimetre per hour would take about a hundred and fourteen years to fill a one-litre bottle. That is why the unit almost never describes a bulk transfer — it describes a process one hopes will stay slow.

One cubic millimetre per hour equals 0.001 millilitres per hour, about 0.01667 cubic millimetres per minute, or one microlitre per hour.

Information about the Cubic centimeter per minute (cm³/min)

The cubic centimetre per minute is a unit of volumetric flow rate equal to one cubic centimetre passing a point every minute. Its symbol is cm³/min, and since a cubic centimetre is a millilitre, mL/min means the same thing. It is the standard unit of controlled gas flow in laboratories and in the semiconductor industry.

That industry gave it an abbreviation of its own: sccm, standard cubic centimetres per minute. The word standard matters, because a gas expands and contracts with temperature and pressure, so a volume flow means nothing until the conditions are pinned down. A mass flow controller set to 50 sccm delivers a fixed number of molecules per minute regardless of what the downstream pressure does, which is precisely what a deposition or etching process requires.

A silicon wafer passing through a plasma etcher meets several such controllers at once — argon at a few hundred sccm, a reactive fluorine compound at tens, oxygen at a handful — and the recipe that defines the process is essentially a list of these numbers against time. Repeating a process in another factory means reproducing the same flows.

Chromatography and gas analysis use the unit at the low end. Helium carrier gas through a capillary column runs at one or two cubic centimetres per minute, a flame detector burns hydrogen at thirty and air at three hundred, and a mass spectrometer's inlet is designed around a flow the vacuum pumps can cope with.

Liquids appear here as well, particularly in analytical chemistry and medicine. A high-performance liquid chromatography pump runs at 0.2 to 2 cubic centimetres per minute, and an intravenous infusion of 100 millilitres over an hour is 1.67 cubic centimetres per minute. In both cases the small, steady rate is what allows the result to be reproduced.

Sixty cubic centimetres per minute is one cubic centimetre per second, and a thousand is a litre per minute. So a typical mass flow controller set to 500 sccm is delivering half a litre of gas a minute — about the volume of a soft-drink bottle, which is a helpful way to picture what an invisible gas line is actually carrying.

One cubic centimetre per minute equals one millilitre per minute, about 0.01667 cubic centimetres per second, or 0.001 litres per minute.