Positive Displacement flow meters, or PD flow meter, provide an excellent solution for applications involving viscous liquids.  This flow measurement technology provides excellent accuracy, delivers readings that are unaffected by high viscosities and changing viscosities, and does not have any requirement for upstream / downstream straight pipe runs. This combination of features makes the PD flowmeter an ideal for situations with tight space constraints and high accuracy requirements. PD meter also provide excellent range-abilty / turndown ratio, making them an excellent choice for low flow measurement applications.