Mariotte's bottle is a device that delivers a constant rate of flow from closed bottles or tanks. It is named after French physicist

Edme Mariotte Edme Mariotte (; ; c. 162012 May 1684) was a French physicist and priest (abbé). He is particularly well known for formulating Boyle's law independently of Robert Boyle. Mariotte is also credited with designing the first Newton's cradle. Biog ...

(1620-1684). A picture of a bottle with a gas inlet is shown in the works of Mariotte, but this construction was made to show the effect of outside pressure on mercury level inside the bottle. It further misses a

siphon A siphon (; also spelled syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in an inverted "U" shape, which causes a liquid to flow upward, abo ...

or an outlet for the liquid.

Invention

The design was first reported by McCarthy (1934). As shown in the diagram, a stoppered reservoir is supplied with an air inlet and a

. The pressure at the bottom of the air inlet is always the same as the pressure outside the reservoir, i.e. the

atmospheric pressure Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1,013. ...

. If it were greater, air would not enter. If the entrance to the

is at the same depth, then it will always supply the water at atmospheric pressure and will deliver a flow under constant head height, regardless of the changing water level within the reservoir. This apparatus has many variations in design and has been used extensively when a constant water pressure is needed, e.g. supplying water at constant head for measuring

water infiltration Infiltration is the process by which water on the ground surface enters the soil. It is commonly used in both hydrology and soil sciences. The infiltration capacity is defined as the maximum rate of infiltration. It is most often measured in meter ...

into

soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...

or supplying the mobile phase in

chromatography In chemical analysis, chromatography is a laboratory technique for the Separation process, separation of a mixture into its components. The mixture is dissolved in a fluid solvent (gas or liquid) called the ''mobile phase'', which carries it ...

. The drawback of the design is that it is sensitive for gas inlet leakage and that during operation liquid cannot be added, since it would change the pressure control. Accurate control is nowadays provided by electronic devices.

Applications

Constant head is important in simplifying constraint when measuring the movement of water in soil. Several measurement techniques employ the Mariotte's bottle to provide constant head. The Guelph Permeameter measures unsaturated hydraulic conductivity in the field and uses this principle to create a constant head. Single and double ring infiltrometers can also use the Marriotte's bottle.Herrick, J. E., Van Zee J.W., Havstad, K.M., Burkett, L.M., Whitford, W.G. Monitoring Manual for Grassland, Shrubland and Savanna Ecosystems, Volume II: Design, Supplementary Methods, and Interpretation. Chapter 8, Single-ring infiltrometer (for water infiltration). https://jornada.nmsu.edu/files/Volume_II.pdf#page=141 Another application is a similar arrangement in some fuel tanks used in

control line Control line (also called U-Control) is a simple and light way of controlling a flying model aircraft. The aircraft is typically connected to the operator by a pair of lines, attached to a handle, that work the elevator of the model. This allo ...

model airplanes, where it is called a "uniflow" tank, where the tank venting tubing goes to the end of the prismatic tank, close to the fuel pick-up tube that feeds the engine; thus, when fuel is consumed, the uniflow tank supplies approximately the same pressure, regardless of the quantity of fuel that remains in the tank for the rest of the flight, which keeps the same carburetor calibration and air-fuel ratio.

References

External links

*{{Commons category-inline, Mariotte bottle Fluid dynamics Soil physics

Invention

Applications

See also

References

Further reading

External links