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hydrometer

 
Dictionary: hy·drom·e·ter   (hī-drŏm'ĭ-tər) pronunciation
 
n.

An instrument used to determine specific gravity, especially a sealed, graduated tube, weighted at one end, that sinks in a fluid to a depth used as a measure of the fluid's specific gravity.

hydrometric hy'dro·met'ric ('drə-mĕt'rĭk) or hy'dro·met'ri·cal adj.
hydrometrically hy'dro·met'ri·cal·ly adv.
hydrometry hy·drom'e·try n.
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A direct-reading instrument for indicating the density, specific gravity, or some similar characteristic of liquids. Almost all hydrometers are made of a high-grade glass tubing. The main body is the float section in the bottom of which ballast, such as small shot, is secured. A small-diameter tube, the stem, extends from the upper end of the float section. Inside the stem is the scale, printed on heavy-grade paper, and well-secured within the stem so its position will not change. When the hydrometer is placed in a liquid, the stem extends vertically above the surface for a portion of its length.

Hydrometers may be classified according to the indication provided by graduations of the scale as follows: (1) density hydrometers, to indicate densities at a particular temperature, and usually for a particular liquid; (2) specific gravity hydrometers to indicate specific gravity of a liquid, with reference to water, at a particular temperature; (3) percentage hydrometers to indicate, at a particular temperature, the percentage of a substance such as salt, sugar, or alcohol dissolved in water (alcoholometers are an example); and (4) arbitrary scale hydrometers, indicating the density, specific gravity, or concentration of a liquid in terms of an arbitrarily defined scale, at a defined temperature. The last group includes the saccharimeter (indicates percentage of pure sucrose solutions); the Baumé hydrometer (measures specific gravity of liquids lighter than water); the lactometer (tests milk); and the barkometer (tests tanning extracts). See also Density; Specific gravity.


 
Columbia Encyclopedia: hydrometer
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hydrometer (hīdrŏm'ətər) , device used to determine directly the specific gravity of a liquid. It usually consists of a thin glass tube closed at both ends, with one end enlarged into a bulb that contains fine lead shot or mercury to cause the instrument to float upright in a liquid. In the glass tube is a scale so calibrated that the reading on it level with the surface of the liquid in which the hydrometer is floating indicates the number of times heavier or lighter the liquid is than water, i.e., the specific gravity of the liquid. The hydrometer is based on Archimedes' principle. The level at which the hydrometer floats depends only on the density of the liquid. Hence this level can be used to measure both the density and the specific gravity, which is proportional to it. Commercial hydrometers are usually calibrated for ordinary room temperature, which is taken to be 20°C (68°F), or for 4°C (39.2°F). Because of the variation in the depth to which the instrument sinks in heavy and in light liquids, one type is made for use in liquids more dense than water and another for use in those less dense than water. The so-called bulb hydrometer consists of a small commercial hydrometer contained in a larger glass tube into which the solution to be tested is drawn by the action of a rubber bulb. It is used to measure the specific gravity of the sulfuric acid solution in automobile batteries. The two Baumé hydrometers (invented by Antoine Baumé), one for specific-gravity determinations in liquids denser than water and the other for liquids less dense than water, are calibrated with the special Baumé scale (also constructed by him).


 
Wine Lover's Companion: hydrometer
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(high-DRAH-mih-ter) Literally meaning "water measurer," a hydrometer is an instrument comprised of a vertical scale inside a sealed glass tube weighted at one end. It's used to measure the ratio (called specific gravity) of the density of a liquid (such as grape must or wine) to that of pure water. A hydrometer floats upright in liquid; the reading is taken where the liquid's surface hits the scale-and the hydrometer floats higher in denser liquid. In winemaking, a hydrometer has many uses including measuring a must's sugar content and calculating its potential alcohol, determining how fermentation is progressing and indicating when it's finished, gauging effervescence in sparkling wines, and measuring a finished wine's alcohol level.

 
Veterinary Dictionary: hydrometer
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An instrument for determining the specific gravity of a fluid.

 
Wikipedia: Hydrometer
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Image:Hydrometer6455.png

A hydrometer is an instrument used to measure the specific gravity (or relative density) of liquids; that is, the ratio of the density of the liquid to the density of water.

A hydrometer is usually made of glass and consists of a cylindrical stem and a bulb weighted with mercury or lead shot to make it float upright. The liquid to be tested is poured into a tall jar, and the hydrometer is gently lowered into the liquid until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer is noted. Hydrometers usually contain a paper scale inside the stem, so that the specific gravity can be read directly.

Contents

Principle

The operation of the hydrometer is based on the Archimedes principle that a solid suspended in a liquid will be buoyed up by a force equal to the weight of the liquid displaced. Thus, the lower the density of the substance, the further the hydrometer will sink. (See also Relative density and hydrometers.) Some historians credit Hypatia of Alexandria with the invention of the hydrometer although there is little evidence to support this.

Ranges

In low density liquids such as kerosene, gasoline, and alcohol, the hydrometer will sink deeper, and in high density liquids such as brine, milk, and acids it will not sink so far. In fact, it is usual to have two separate instruments, one for heavy liquids, on which the mark 1.000 for water is near the top of the stem, and one for light liquids, on which the mark 1.000 is near the bottom. In many industries a set of hydrometers is used — covering specific gravity ranges of 1.0–0.95, 0.95–0.9 etc — to provide more precise measurements.

Scales

Modern hydrometers usually measure specific gravity but different scales were (and sometimes still are) used in certain industries. Examples include:

  • Baumé scale, formerly used in industrial chemistry and pharmacology
  • Brix scale, primarily used in fruit juice, wine making and the sugar industry
  • Oechsle scale, used for measuring the density of grape must
  • Plato scale, primarily used in brewing
  • Twaddell scale, formerly used in the bleaching and dyeing industries [1]

Commercial uses

A hydrometer (and thermometer) being used to check the specific gravity of a batch of homebrew beer.
A modern hydrometer in a sugar solution

Because the commercial value of many liquids, including sugar solutions, sulfuric acid, and alcohol beverages such as beer and wine, depends directly on the specific gravity, hydrometers are used extensively.

Lactometer

A lactometer is a hydrometer used to test milk. The specific gravity of milk does not give a conclusive indication of its composition since milk contains a variety of substances that are either heavier or lighter than water. Additional tests for fat content are necessary to determine overall composition.

Alcoholometer

An alcoholometer is a hydrometer which is used for determining the alcoholic strength of liquids. It is also known as a proof and traille hydrometer.

Saccharometer

A saccharometer is a hydrometer used for determining the amount of sugar in a solution. It is primarily used by brewers and winemakers.

Thermohydrometer

A thermohydrometer is a hydrometer that has a thermometer enclosed in the float section.

For measuring the density of petroleum products, like fuel oils, the specimen is usually heated in a temperature jacket with a thermometer placed behind it since density is dependent on temperature. Light oils are placed in cooling jackets, typically at 15oC. Very light oils with many volatile components are measured in a variable volume container using a floating piston sampling device to minimize light end losses.

As a battery test it measures the temperature compensated specific gravity and electrolyte temperature.

Soil analysis

A hydrometer analysis is the process by which fine-grained soils, silts and clays, are graded. Hydrometer analysis is performed if the grain sizes are too small for sieve analysis. The basis for this test is Stoke's Law for falling spheres in a viscous fluid in which the terminal velocity of fall depends on the grain diameter and the densities of the grain in suspension and of the fluid. The grain diameter thus can be calculated from a knowledge of the distance and time of fall. The hydrometer also determines the specific gravity (or density) of the suspension, and this enables the percentage of particles of a certain equivalent particle diameter to be calculated.

See also

References

  1. ^ http://chestofbooks.com/reference/Encyclopedia-Of-Practical-Receipts-And-Processes/Degrees-of-Baum-e.html

Sources




 
Translations: Hydrometer
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Dansk (Danish)
n. - hydrometer

Nederlands (Dutch)
hydrometer

Français (French)
n. - aéromètre

Deutsch (German)
n. - Hydrometer

Ελληνική (Greek)
n. - (φυσ.) αραιόμετρο, πυκνόμετρο

Italiano (Italian)
idrometro

Português (Portuguese)
n. - hidrômetro (m) (Fís.)

Русский (Russian)
гидрометр

Español (Spanish)
n. - hidrómetro

Svenska (Swedish)
n. - areometer, sänkvåg

中文(简体)(Chinese (Simplified))
液体比重计, 浮秤

中文(繁體)(Chinese (Traditional))
n. - 液體比重計, 浮秤

한국어 (Korean)
n. - 액체 비중계, 부칭

日本語 (Japanese)
n. - 液体比重計

العربيه (Arabic)
‏(الاسم) المسيل مقياس, الثقل النوعي للسوائل‏

עברית (Hebrew)
n. - ‮מד-מים, מד-צפיפות הנוזלים, הידרומטר‬


 
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Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved.  Read more
Sci-Tech Encyclopedia. McGraw-Hill Encyclopedia of Science and Technology. Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved.  Read more
Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/  Read more
Wine Lover's Companion. Wine Lover's Companion. Copyright © 2003 by Barron's Educational Series, Inc. All rights reserved.  Read more
Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.  Read more
Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Hydrometer" Read more
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