API/ASTM ThermoHydrometers and Plain Hydrometers are devices for measuring the density of liquids and gases. Although API 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.
API/ASTM Hydrometer scales are numerous. There are many scales in common use today in different industries and applications; such as Specific Gravity Hydrometers, API/ASTM Hydrometers, Baumé Hydrometers, Brix Hydrometers, Twaddle Hydrometers, Plain Form Hydrometers, etc..
Certified Hydrometers are available upon request. API/ASTM hydrometers are certified at three points on the hydrometer scale as specified by NIST (formerly NBS). On the combined form, the thermometer is provided with a 60 degree F test point correction. Each API/ASTM ThermoHydrometer is accompanied by a document of certification that includes the correction of each point tested.
All API/ASTM hydrometers are made in accordance with API specifications and calibrated to API scale Modulus 141.5 at 60 degrees F. All API/ASTM hydrometers are of precision grade. The API hydrometers are constructed with a solid alloy ballast and designed to permit quick penetration to the settling point, creating no air bubbles. The API hydrometer scale is sealed in place by a red glass strap fused to the stem of the hydrometer and the top of the gravity scale even with the last number line.
Hydrometer Cases for carrying three 15 inch hydrometers. It is made of plastic with separate compartments, for each compartment lined with felt. The lid has a 37-degree angle cut, which allows it to arc away from the hydrometers when open, thus preventing stem breakage. There are two models to choose from. One model has a spring loaded hinge that holds the lid open or closed under spring tension and the other model is equipped with a standard hinge and a positive tension-type latch which holds the lid securely closed until released.
Hydrometer Cylinders are ideal for use in testing the gravity of crude oil. The hydrometer cylinders are transparent and light weight. The graduated hydrometer cylinder is calibrated to contain/deliver at 20 degrees C. Single molded-in metric scale, transparent with pour-out spout. This hydromer cylinder is compatible with virtually any chemical for typical brief use. Hydrometer cylinder is shatterproof with large base.