Pycnometer Specific Gravity Bottle

Arthur H. Thomas Hydrometer for Liquids Lighter than Water Westphal Specific Gravity Balance Pycnometer Specific Gravity Bottle Lypkin Pycnometer... 

For non-porous solids the particle density is equal to the true, skeletal, or absolute density, Pabs which can be measured using either a specific gravity bottle or air pycnometer ... 

Determination of Specific Gravity.— The determination of the specific gravity, usually in the case of liquids only, is made by means of a pycnometer or specific gravity bottle. The pycnometer is filled with the liquid, at a definite temperature, and weighed. The weight of the pycnometer empty, and the weight of it when filled with water at a definite temperature, must also be known or must be determined. 

Figure 4.2 A A pycnometer (or specific gravity bottle ) is an accurate volumetric flask whose weight change when totally filled with liquid gives the density of that liquid. B A hydrometer measures the buoyant density of the fluid by the level at which it floats...

The determination of the specific gravity of the various distillates and residues is clearly a key element in the determination of ethanol by distillation. Such determinations by specific gravity bottle or pycnometer are well established and will not be described here. However, the use of hydrometers for this purpose now requires that only hydrometers complying with BS 5471 1977 can be used for official analyses in the UK. 

For non-porous solids, this is easily measured by a gas pycnometer or specific gravity bottle, but these devices should not be used for porous solids since they give the true or absolute density p bs the material of which the particle is made and this is not appropriate where interaction with fluid flow is concerned ... 

When greater accuracy is required or when only small quantities are available, 1 iquid densities are best obtained from the mass required to fill a vessel of accurately defined volume, e.g., a specific gravity bottle (p.217) or a pycnometer. With careful technique, the densities measured with pycnometers are precise to five significant figures. 

A preliminary step necessary to precise work with the pycnometer is the determination of its two volume constants that is, the constants of the linear equation expressing die capacity as a function of die temperature. This is done by filling with distilled water and weighing accurately several times at each of two temperatures near the ends of the range for which the pycnometer is to be used. The bottle form is also adapted to the precise measurement of densities of solids. See also Specific Gravity. 

Specific Gravity, also called absolute density, is the relation betw wt and volume of grains disregarding che air spaces. The Bofors manual(Ref 10,p 22) describes two methods Mohr-Wesrphal s balance and pycnometer methods. In the BurMines method(Ref 2,p 67), an apparatus called densimeter is used. In US Spec JAN-P-223A(Ref 11) two methods are described in which either a 25-ml bottle with a 10-g sample or a large... 

Specific gravity is the density (mass per volume) of the sample compared to the density of water (see Table Gl.5.7 in Anticipated Results). Samples are equilibrated to the same temperature and weighed using a pycnometer. The pycnometer is a sample bottle that provides a constant volume. 

There are other methods for the determination of density. These include the specific gravity balance and the use of a pycnometer (weighing bottle). 

A modified pycnometer has also been used by Schurecht for the determination of the volume of test specimens. It consists essentially of a wide-mouth cylindrical glass vessel provided with a ground in, hollow stopper which has a tube in its center. The volume of this piece is computed from the relation v — w — wi + h)/8, where V = volume of specimen w = weight of bottle plus liquid in grams Wi = weight of bottle plus liquid plus specimen b = weight of saturated test piece, and 5 = specific gravity of liquid. 

The specific gravity of milk can be used to determine the total solids (TS) content and is usually measured by either a standard hydrometer or with a pycnometer (density bottle) after gentle mixing. The effect of different temperatures can be corrected using a table. The TS of the milk can be calculated if the fat content is known by using Richmond s formula ... 

Pycnometer. A small bottle having an accurately-ground glass stopper pierced with a capillary. The bottle is of known volume and is used for the accurate determination of the specific gravity of a material. 

Specific gravity or API gravity is measured by means of hydrometers (D287), pycnometers (D941 and D1217), or the chainomatic specific-gravity balance if very many small samples (16 cc) must be tested. For viscous oils or semisolid bitumens, a pycnometer (D70) or weighing bottle may be used, for solids an analytical balance (D71) equipped with a pan straddle. 

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