Hydrometer, Baume

Cartier s Hydrometer. This hydrometer shows a reading of 22° when immersed in a solution having a density of 22° Baume but the scale divisions are smaller than on the Baume hydrometer in the ratio of 16 Cartier to 15 Baume. 

Baume hydrometer scale phys chem A calibration scale for liquids that is reducible to specific gravity by the following formulas for liquids heavier than water, specific gravity = H5 a- — n) at 60°F for liquids lighter than water, specific gravity = 140 a- (130 + n) at 60°F n is the reading on the Baume scale, in degrees Baume Baume is abbreviated Be. bo ma hT dram-ad-ar, skal )... 

Specific Gravity.—The sp. gr. of tanning solutions is determined (usually at 150 C.) with the Westphal balance or with a hydrometer or, in industrial practice, with the Baume hydrometer.2... 

Degrees Baume Transfer about 200 mL of sample, previously cooled to a temperature below 15° into a 250-mL hydrometer cylinder. Insert a suitable Baume hydrometer graduated at 0.1 °Be intervals, adjust the temperature to 15.6°, and note the reading at the bottom of the meniscus. 

Baume hydrometers for use with this table must be graduated by the above formula, which should always be printed on the scale. 

Sprayometer (Parrot and Stewart). This hydrometer which is used in determining the density of lime sulfur solutions has two scales one scale is graduated from 0° to 38° Baume and the other scale is from 1.000 to 1.350 specific gravity. 

Twaddell Hydrometer. This hydrometer, which is used only for liquids heavier than water, has a scale such that when the reading is multiplied by 5 and added to 1000 the resulting number is the specific gravity with reference to water as 1000. To convert specific gravity at 60°/60°F to Twaddell degrees, take the decimal portion of the specific gravity value and multiply it by 200 thus a specific gravity of 1.032 = 0.032 X 200 = 6.4° Tw. See also special table for conversion to density and Baume scale. 

This table gives the relation between density (c.g.s.) and degrees on the Baume and Twaddell scales. The Twaddell scale is never used for densities less than unity. See also Sec. 2.1.2.1, Hydrometers. 

Density. Measurement of density is widely used in the sugar industry to determine the sugar concentration of symps, Hquors, juices, and molasses. The instmment used is called a hydrometer or a spindle. When it is graduated in sucrose concentration (percent sucrose by weight), it is called a Brix hydrometer or a Brix spindle. Brix is defined as the percent of dry substance by hydrometry, using an instmment or table caUbrated in terms of percent sucrose by weight in water solution. Hydrometers are also graduated in °BaumH, stiU in use in some industries. The relationship between °BaumH and density, ing/cm, is °Baumn Baum e = 145(1 — 1/d). 

Hydrometers are calibrated in density, specific gravity, and several arbitrary units such as degrees Baume (°Be), degrees American Petroleum Institute (°API), or °Brix. These units are used for specialized purposes in various industries. The relationship between the specific gravity (sp. gr.) of a liquid with a density less than water and these specialized units is given by the following equations ... 

To convert hydrometer readings or specific gravities to °Baume for liquids heavier than water, the following formula is used ... 

Antoine Baum , 1728-1804. French pharmacist and chemist. Author of a Chymie expenmentale et raisonnee in which he discussed chemical apparatus, chemical affinity, fire, air, earth, water, sulfur, gypsum, alum, clay, niter, gunpowder, borax, arsenic, glass, porcelain, and the common acids, alkalies, metals, and ores used m 1773. His hydrometer scale is still used. He was one of the first chemists to investigate platinum... 

Users of the Baum method found that the scale generally read 66 when llie float was submerged in oil of vitriol. Thus, early manufacturers of hydrometers calibrated the instruments by this method. There were variations in the Baumd scale, however, because of lack of standardization in hydrometer calibration. Consequently, in 1904, the National Bureau of Standards made a careful survey and finally adopted the scales previously given for light and for heavy liquids. 

However, a considerable number of hydrometers calibrated according to the Baume scale were found at an early period to be in error by a consistent amount, and this led to the adoption of the equation ... 

Baume (Be) units arise from an arbitrary system of graduating hydrometers in degrees for determining the specific gravity of a solution. Within the com refining industry, Baume is related to specific gravity by the following equation 6... 

The modulus of 145 is the ratio of the total volume displaced in water by the hydrometer and the volume displaced by the unit scale length of the hydrometer stem. Corn syrups are commercially available with Baume values of 42,43 and 44. 

As the density gradient along the evaporator develops, a concomitant increase in boiling temperature also is found (Isselhardt et al., 2007). Raw sap boils at 212 °F, and syrup at 66.5 °Bx boils at 219.3 °F (at standard atmospheric pressure). Most producers use a hydrometer, calibrated in Brix or Baume and corrected for temperature, to determine the finished syrup density. 

Specific Gravity Determine at 15.6° with a hydrometer, or calculate it from the degrees Baume observed in the Degrees Baume Test. 

Baum s original hydrometer for liquids lighter than water was based on a zero point given by 10 parts of salt in 90 parts of water and 10° for pure water, the hydrometer stem then being divided in equal divisions. The 15° point on the heavier than water instrument is supposed to be the specific gravity of a solution of 15 parts salt in 85 parts of water Cartiers hydrometer was probably only an infringement of Baum6 s. 

The concentration of sulphuric acid (H,SO,) can be determined by using Baume s ("Be) hydrometer. Table4.3 shows the relationship between "Be and sulphuric acid concentration. The conversion of Baume to specific gravity (SG) for liquids heavier than water can be conducted using Equation [4.6] ... 

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