Density meter

Fig. 25. Nuclear density meter for on-line measurement of slurry density (6).

The proof content is determined by the use of a standardized hydrometer with a standardized thermometer. The alcohol content can also be determined by the use of an immersion refractometer, a pycnometer, or a density meter. 

With this relationship for all samples was calculated from ninh This M is used for evaluating the reaction data. The ultracen rifuge (u.c measurements were carried out in a Spinco model E analytical ultracentrifuge, with 0.4% solutions in 90% formic acid containing 2.3 M KCl. By means of the sedimenta- ion diffusion equilibrium method of Scholte (13) we determine M, M and M. The buoyancy factor (1- vd = -0.086) necessary for tSe calculation of these molecular weights from ultracentrifugation data was measured by means of a PEER DMA/50 digital density meter. 

To predict the composition, a density meter is installed beside the column. Samples from the feed, distillate, bottoms, and trays 2, 4, 6, 8, 10, and 12 are sent to this density meter through a sampling pump. The samples can be selected from different points by the use of several valves available on the sampling lines. In order to make this sampling continuous, a Taylor Control Language program has been written in... 

Density (the mass of liquid per unit volume at 15°C) and the related terms specific gravity (the ratio of the mass of a given volume of liquid at 15°C to the mass of an equal volume of pure water at the same temperature) and relative density (same as specific gravity) are important properties of petroleum products as they are a part of product sales specifications, although playing only a minor role in studies of product composition. Usually, a hydrometer, pycnometer, or digital density meter is used for determination in all these standards. 

Fig. 3. Chain-balanced float or plummet-type specific gravity or density meter Differential-pressure Method...

Any combination of flowmeter and suitable specific gravity (density) meter (Section 6.6) can in theory be employed to produce a mass rate of flow. However, these so-called indirect meters have a limited range and accuracy and require careful and frequent calibration and maintenance. An instrument based on the turbine flowmeter (Volume 1, Section 6.3.9) and acoustic density meter (Section 6.6.1) has been employed with good results<8) (see Fig. 6.5). 

The vibrating cylinder version of this type of transducer employs a sensing element of the straight tube type and is similar to the vibrating cylinder density meter (Section 6.6.1). The cylinder is maintained in oscillation by a feedback amplifier/limiter combination and its frequency of oscillation varies with the pressure of the fluid within it, which alters the hoop stress on the cylinder. As with the vibrating wire, the frequency of oscillation increases with the fluid pressure. In order to be able to use the sensor for the measurement of absolute pressures, it is surrounded with a cylindrical housing and the annular space between the two is evacuated. Such sensors give excellent repeatability and have a relatively low temperature sensitivity. 

Fig. 6.34. U-Tube specific gravity (density) meter and pneumatic transmitter...

Eqau Calibration constant for acoustic gas density meter kg/m3s2 ML 3T ... 

Elam Transducer constant for acoustic liquid density meter kg/m3 ML 3... 

The use of a precision digital density meter as supplied by Mettler Instruments (Anton Paar, Ag.) appeared attractive. Few references on using density measurements to follow polymerization or other reactions appear in the literature. Poehlein and Dougherty (2) mentioned, without elaboration, the occasional use of y-ray density meters to measure conversion for control purposes in continuous emulsion polymerization. Braun and Disselhoff (3) utilized an instrument by Anton Paar, Ag. but only in a very limited fashion. More recently Rentsch and Schultz(4) also utilized an instrument by Anton Paar, Ag. for the continuous density measurement of the cationic polymerization of 1,3,6,9-tetraoxacycloundecane. Ray(5) has used a newer model Paar digital density meter to monitor emulsion polymerization in a continuous stirred tank reactor train. Trathnigg(6, 7) quite recently considered the solution polymerization of styrene in tetrahydrofuran and discusses the effect of mixing on the reliability of the conversion data calculated. Two other references by Russian authors(8,9) are known citing kinetic measurements by the density method but their procedures do not fulfill the above stated requirements. 

The Jerguson gage is immersed in a constant temperature bath with silicon fluid as the heat-transfer medium, that also thermostats the density meter. The bath temperature is controlled to . 01 K with a Thermomix 1460 temperature regulator and temperature is measured with a calibrated mercury-in-glass thermometer to within. 01 K. The lines external to the bath are maintained at the bath temperature with the help of heating tapes and temperature at several points is monitored with thermocouples. Pressure is measured with two calibrated Heise pressure indicators to within .16 bar for pressures up to 160 bar and to within .4 bar for pressures up to 350 bar. 

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