Accurate measurement of viscous liquid with low pressure drop

A Dutch manufacturer of polyurethane foam, also known as PU foam, was looking for a flowmeter with excellent accuracy over a wide measurement range in order to ensure a consistent product quality of the foam.

To ensure a consistent product-quality of foam, the foam must be measured accurately. Previously, the manufacturer used a bent-tube mass flowmeter from another manufacturer for this application. Due to the high viscosity of the foam, this resulted in a less accurate measurement.

The installation for foam liquid (Polyol) is built to supply a max. pressure up to 40 bar. A delta P of up to 8.5 bar is acceptable for this purpose. The required accuracy for this installation is < 0.5%. At the minimum flow, however, the accuracy may be max 2% of the measured value.

KROHNE offers with the OPTIMASS 7400 T15 coriolis mass flowmeter, with straight measuring tube, the solution. This allows an accurate and long-term reliable measurement of Polyol, according to customer requirements. This enables the customer to produce high quality polyurethane foam. The low pressure loss of the straight measuring tube, eliminates the need for an increase in pump capacity. Thus, the manufacturer saves on purchase as well as energy costs.

With this mass flowmeter, the customer achieves the desired accuracy (<0.5%) over the largest measurement range and meets customer requirements for minimum flow for this high viscosity fluid (~20,000 mPa.s).

The single straight measuring tube limits the pressure drop to 8.5 bar at maximum flow. The customer can thus use a pump diameter of his choice. When applying a mass flowmeter with a bent measuring tube, a larger pump is required due to a pressure drop of 40 bar. With a larger diameter bent-tube mass flowmeter, the pressure drop will remain within the specified requirement, but will decrease in accuracy.
For the manufacturer, the OPTIMASS 7400 is the best solution for this application: a  substantial costsavings on both purchase and energy costs.

Highlights OPTIMASS 7400

• Coriolis mass flowmeter with single straight tube for advanced applications with viscous media

• Mass, density and volume flow of gases and liquids; maintains operation even with entrained gas up to 100%.

• Extensive sensor and process diagnostics (incl. NE 107)