Zematra manufactures a density unit which is fully in accordance with the specifications as mentioned in ASTM D1298 and IP 160. The sample is poured into a density tube and this tube is then placed in a thermostatic controlled heater column to heat up the sample to 50ºC.
After checking the temperature a hydrometer is placed in the sample. Together with the hydrometer reading and a graph, one can now determine the density of the sample (fuel oil or lube oil) at 15ºC.
The density unit of Zematra consists of the following equipment:
- Density heater (thermostatic controlled heater column)
- ASTM 12C thermometer
- 4 hydrometers, range from 0,850 - 1.050 kg/cm3
- 2 density tubes
Why test for Density:
The most important thing to test the density of the received bunkers is money. The fuel ordered to bunkered is always in metric tones of in other words volume, however the owner is receiving the invoice of the bunkers by weight. A representative drip sample during the whole bunker period is tested on its gravity with a result of 985,0 kg/m3. The bunker suppliers receipt is showing e.g.
Ordered bunkers 1500 m/t, with a density of 995,0 kg/m3, actual delivered 1507,54 m3 due to the difference in density you received shortage of about 15,07 m/t, assuming bunker price of USD 650,00 m/t you have paid USD 9,795 too much for this bunker, please note that an official independent laboratory must also test for density. Calculation as follows; 1500 x ((995-985)/995= 15,07 m/t. Fuel can also be tested for density to calculate the proper density ring for your separators in order for optimum performance of the separators.
Density with heating