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gfglass.com
Manufacturers of Hydrometers and Thermometers Since 1907
INTRODUCTION
Hydrometers are devices for measuring the density of liquids and gases. Although hydrometers actually measure density, it is commonly expressed in the terms of specific gravity, which is the ratio of the density of the substance being measured to the density of water at the same temperature.
In exacting, scientific observations, the reference may be to pure (double-distilled) water at 40°C (39.2°F) In engineering practice, the reference frequently is to pure water at 15.6°C (60°F). A value of unity is established for water, 1.000. Thus liquids with a specific gravity less than 1.000 are lighter than water; those with a specific gravity greater than 1.000 are heavier than water.
The specific gravity for a given gas is the ratio of the density of the gas to the density of air. Since the density of air varies markedly with both temperature and pressure, exacting observations should reflect both conditions. Common reference conditions are 0°C (32°F) and 1 atmosphere.
Hydrometers scales are numerous. There are many scales in common use today in different industries and applications; such as Specific Gravity, API, Baumé, Brix, Twaddle, etc..
Greers Ferry Glass Works' (now sold as Thermo Scientific) hydrometers incorporate features which make them the finest as well as the most accurate instruments available. The degree of accuracy is guaranteed to be greater than that required by the A.S.T.M or the N.I.S.T.Our reputation in this field as makers of standard gravity testing instruments dates back to the beginning of our organization. The wide scope of our experience in manufacturing hydrometers ranges from 1907 Coal Oil Hydrometers and Gay Lussac Hydrometers; to Special Ballasted Precision Hydrometers for Nuclear Submarines and Hydrogen Peroxide Hydrometers for missile fuel.
Our NIST Certified Standards for manufacturing cover the years from the present back to 1917. We state these facts to introduce you to our capabilities.
We have a full line of catalogs that we can send at your request. Please feel free to
Phone: 501 589-2947...........Fax: 501 589-2285.........Email: gfgw@hotmail.com
