DMA 35 Portable Density/Specific Gravity/ Concentration Meter - Alber

EN• Do not leave sample/rinsing containers uncovered. Clean all spillagesimmediately.• Make sure that the setup location is sufficiently ventilated. The environment ofDMA 35 must be kept free of flammable gases and vapors.• Supply a fire extinguisher.3 Measuring PrincipleDefinition of densityThe density ρ of a sample is defined as its mass divided by its volume:mρ = ----VDensity is a temperature-dependent measuring unit.The oscillating U-tube principleThe sample is introduced into a U-shaped borosilicate glass tube that is being excitedto vibrate at its characteristic frequency electronically. The characteristic frequencychanges depending on the density of the sample. Through determination of thecharacteristic frequency the density of the sample can be calculated. Due to thetemperature dependency of the density value, the temperature of the sample has tobe determined precisely.Concentration measurementIn binary mixtures, the density of the mixture is a function of its composition. Thus, byusing density/concentration tables, the density value of a binary mixture can be usedto calculate its composition.This is also possible with so-called quasi binary mixtures. These are mixturescontaining two major components and some additional ones which are present in verysmall concentrations compared to the two main components. Many decarbonated softdrinks, for example, can be considered to be quasi binary mixtures of sugar in waterbecause the concentration of flavors and acids are very small compared to sugar andwater. Thus, the sugar concentration can be measured with a density meter.12 C96IB01