Degrees twaddell

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. 

As regards strengths of solution, in some factories the use of Baum6 degrees is preferred, whilst in others Twaddell degrees are the custom, and we have therefore given the two figures in all cases. 

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. 

A scale for expressing the specific gravity of liquids, named after William Twaddell, whereby 200 degrees Twaddell equates to a sg of 1. 

TABLE 1-13 Specific Gravity, Degrees Baume, Degrees API, Degrees Twaddell, Pounds per Gallon, Pounds per Cubic Foot ... 

In this table there is opposite a list of different densities, the quantity of dry acid per oent., either diy or monohydrated. To bring the degrees of T Waddell s hydrometer to those of the real specific gravity, it is only necessary to multiply the first by five, and add one thousand thus, supposiug a sample of vitriol to stand t50° on TWaddell s hydrometer, multiply this 150° by 5s, and one has 750° to this add 1000°, and the specific gravity 1 750° is obtained. Now, to ascertain the amount of real sulphuric acid in this sample, it is only necessary to run through the table and hud the density 1-750°, or the nearest approach to it which in this ease is 1 746°, It will be found then that the sample would contain eiglity-three per cent, of the monohydrated acid, or 67 68 per cent, of dry acid. 

Note Special density units called degrees Baume (°Be), degrees API (°API), and degrees Twaddell (°Tw) are occasionally used, particularly in the petroleum industry. Definitions of and conversion factors for these units are given on p. 1-20 of Perry s Chemical Engineers Handbook. 

Tw. Abbreviation for Twaddell, used in reporting specific gravities for densities greater than water, as degrees Tw. A twaddell reading, multiplied by five and added to 1000, gives specific gravity with reference to water as 1000. 

Twaddell s hydrometer is used in England for liquids heavier than water. Its degrees are converted into speoi fio gravities by multiplying them by 5, adding 1,000, and dividing the sum by 1,000, Thus —... 

COMPARISON OP DEGREES, TWADDELL AND BAUME, WITH ACTUAL DENSITIES. 

Degrees 1 Twaddell. Specific gravity. Per cent, by weight of Lb. of actual NaOH contained in 1 gallon ot lye made from commercial caustic of ... 

Comparison of Degrees, Twaddell and BaumiS, with Actual Drnkitieh. 147... 

This is a hydrometer used for meeisuring density (specific gravity) of industrial liquids which are greater than one. Measures of specific gravity between 1 and 2 are divided into 200 equal parts, and each division is 1 degree. The specific gravity of a solution equals the number of degrees on the Twaddell scale multiplied by 5 and divided by 1,000. The Twaddell is named for its inventor. 

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