Test Procedure and Evaluation
The specimen material is filled into a glass beaker which must be large enough to enable the density ball to be immersed up to the middle of the neck section of the holding rod.
The density ball and specimen material are then heated to a temperature of 20 ± 0,5°C using either a temperaturecontrolled chamber or a water bath.
The beaker with the specimen material is then placed on a laboratory balance.
The holding rod of the density ball is clamped onto the support in such a way that the ball can easily be moved upwards and downwards by hand.
The beaker with contents must be weighed to an accuracy of ± 10 mg in the case of Model 475/I, or ± 1 mg in the case of Model 475/III.
The beaker with the specimen material remains on the balance whilst the sphere is slowly lowered into the liquid by hand and immersed up to the middle of the holding rod neck.
The weighing procedure is then repeated.
The following equation is applied to calculate the density ρ of the specimen in g/ml at test temperature t:
W1: Weight in g of beaker filled with specimen material prior to immersing the sphere
W2: Weight in g shown on balance after the sphere has been immersed
V: Volume in ml of the spherical body up to the middle of the neck of the holding rod
ρL: Air density = 0.0012 g/ml
The determined density should be specified to an accuracy of 0.001 g/ml and the reference temperature stated.
Note:
Care should be taken that air bubbles in the test liquid are eliminated by allowing it to stand or by stirring it carefully. Bubbles on the sphere can be removed by rotating the same.
The density ball method is not suitable for testing specimens with rapid sedimentation properties. In such cases the density should be determined by using a Pycnometer, Model 290.
Important Notice:
Due to the relatively high weight of approx. 780 g of the balls (the balls are turned on a lathe from solid material) the holding rod with the ball should always been held in a vertical position to avoid an unnecessary stress of the neck section.
For the same reason do not shake off the liquid measured from the ball or charge the ball laterally, e.g. when cleaning it with a brush.
Reference Class:
All versions of Model 475 are supplied with a Manufacturer’s Certificate M in accordance with DIN 55 350-18 that includes among others the following information:
Test temperature, ball’s volume, product identification, test equipments used with calibration status, date, name of inspector.
It is proved that the deviation of the ball’s volume from the setting value is less than 0.1 %.
The density balls can also be supplied with a certificate issued by the Official Bureau of Weights and Measures.
Order Information
Order No. Name of Product
101-0010.01.31 Density Ball, Model 475/I, Volume 100 ml ± 0.1 % (at 20°C)
101-0010.03.31 Density Ball, Model 475/II, as Order No. 101-0010.01.31, but with certificate issued by the Official Bureau of Weights and Measures
101-0010.02.31 Density Ball, Model 475/III, Volume 10 ml ± 0.1 % (at 20°C)
101-0010.04.31 Density Ball, Model 475/IV, as Order No. 101-0010.02.31, but with certificate issued by the Official Bureau of Weights and Measures
Accessories
Order No. Name of Product
101-0020.02.32 Holding device
101-0020.01.32 Table stand with swivel arm
