TITAn presents: Flow Measurement of High Viscosity Liquids

Titan's Oval Gear flow meters ideally suited for high viscosity liquids above 1000cSt

Flow Measurement of High Viscosity Liquids

There are few industries as demanding as the chemical and petrochemical industry when it

comes to liquid flow measurement and control.

Positive Displacement flow measurement devices, such as Titan Enterprises’ Oval Gear

(OG) flowmeters, are one of the most widely used types of flow meter for measuring the flow

of petroleum liquids and petrochemical additive injection fluids. They remain a solid choice

for many applications in today’s modern process control environment, due to the OG’s

suitability in harsh environments, high-pressure capability, and long-term reliability with

minimum maintenance. They are also ideally suited for viscous fluids.

High viscosity liquids, such as fuels, thick oils, bitumen, resin and tar, require devices that

are precision engineered to provide highly accurate flow measurement. The teeth in an oval

gear meter are used to drive the gear and seal the central path, with the differential force

being developed by the shape of the ovals rather than the gear teeth on the lobe. Oval Gears

vary in size and shape depending on the resolution and flow requirement of the process

application.

The pressure drop is essentially the limiting factor when it comes to metering high viscosity

liquids within an application. The Oval Gears within these flow measurement devices provide

a larger surface area generating a much greater driving pressure across the gears. This

results in a wider flow range capability and lower pressure drop (see graph below) compared

to other positive displacement meter types.

Neil Hannay, Titan Enterprises’ Senior Development Engineer, says: “The higher the

viscosity of a liquid, the more pressure will be required to ‘force’ the liquid into the flowmeter

and around the oval gears. It’s important to bear this in mind when selecting the correct size

of oval gear flowmeter for your application. For example, more pressure will be required to

push through resin than diesel.”

Almost immune from the effects of varying liquid viscosity, density and temperature, the

measurement accuracy of Titans’ Oval Gear (OG) flowmeters improves as liquid viscosity

increases, from a nominal 1% to around 0.1% of flow rate at higher viscosities. Titan’s standard OG models provide high accuracy up to 1000 cSt; for viscosities above 1000 cSt

Titan’s specially profiled gears are supplied to facilitate additional flow of the liquid.

Titan Enterprises offer special options and adaptive designs of its Oval Gear meters to meet

specific high-pressure requirements, aid chemical compatibility, and ensure safe operation in

potentially explosive atmospheres. Titan’s Oval Gear range of meters include ATEX

compliant IP65/NEMA 4 protection models, and devices that offer intrinsically safe options for

processes that operate within harsh environmental conditions, such as explosive or corrosive

atmospheres, where flowmeters are required to withstand tough environments whilst

maintaining accurate and reliable measurement.

Titan’s Oval Gear meters can be pressure tested in-house up to 950 bar for custom-designed

models and calibrated against diesel upon request. In the chemical industry, oval gear

flowmeters are often used in conjunction with a batch controller to allow for the automatic

dispensing of pre-set volumes of chemicals.

For further information on the full range of Oval Gear flowmeters or to discuss your specific

OEM application, please contact Titan Enterprises on