Floating bead is a kind of can float to the surface of fly ash hollow ball, are pale, thin wall hollow, composition is given priority to with silica and 3 oxidation 2 aluminium, with fine grain, hollow, qualitative light, high strength, wear resistance, high temperature resistant, thermal insulation, insulation, flame retardant and other functions, is now widely used in refractory materials, lightweight castable production and oil drilling.

　　In the application of floating bead, density, static strength, floating rate is one of the important indicators to measure drift beads quality value, due to the special physical properties drift beads, traditional impregnation cannot effectively density measurement of drift beads, mostly using pycnometer for testing, but as a result of drift beads material is qualitative light, often there are some subtle powder materials, the powder easy to be vacuum suction, and then to improve the test precision floating bead density test precision, make up for the inadequacy of pycnometer method, real density analyzer, using the method of gas displacement, accurate measuring the density of the drift beads.