Oval Gear Meters are a member of the Positive displacement flowmeter family.  They operate by repeatedly filling and emptying compartments of a known volume with a liquid. The flowrate is then calculated based on the number of times these compartments are filled and emptied.

Construction/Design Principle:
The design of the oval gear flow meter is relatively simple; oval shaped gear-toothed rotors rotate within a chamber of specified geometry. As these rotors turn, they sweep out and trap a very precise volume of fluid between the outer oval shape of the gears and the inner chamber walls with none of the fluid actually passing through the gear teeth .

Advantages:  Given it's immunity to the most viscous of fluids, oval gear meter are  ideally suited for measurement of viscous fluids or those with varying viscosities such as oils, syrups and fuels.  

Ease of installation is another advantage of the oval design. Because no straight pipe runs or flow conditioning are required, oval gear meters can be installed in tight areas where alternate technologies would fail

Disadvantages:  Oval-gear meters are generally not recommended for water or water-like fluids, because the increased risk of fluid slippage between the gears and chamber walls. Fluids should be clean and non-corrosive, preferably medium to high viscosity.

Typical Applications: