Online Viscometer Selection Guide

In industrial processes, in-line viscosity measurement is a key link in ensuring product quality and process optimization. Different processes and environments have put forward diverse requirements for the selection of viscometers, and this article provides a detailed set of online viscometer selection processes and key factors to help engineers choose the right equipment for various application scenarios.

1. Understand the application requirements

(1) Fluid description

The accuracy of viscosity measurement is closely related to the characteristics of the liquid to be measured, so the physical properties of the liquid need to be determined before selecting the model. These features include:

• Viscosity (unit: cP, cSt, SSU, CUP, etc.)

• Temperature in °C/°F

• Pressure (in PSI/BAR/mmHg)

• Flow Rate (Unit: LPM/GPM)

• pH

• Particle size (in microns/micron or mesh/mesh)

• Solids content (in percentage)

(2) Production conditions

In production, the viscosity of a liquid fluctuates with changes in conditions such as temperature and pressure. In order to adapt to the needs of the production process, it is advisable to record the minimum, normal and maximum viscosity values of the liquid in order to select a viscometer with the appropriate measuring range.

2. Be clear about how to install it

The way the in-line viscometer is installed affects the stability and accuracy of the measurement. According to the installation location, it can be divided into:

• In-pipe: suitable for continuous flow processes.

• In-tank installation: suitable for batch production and use in mixing tanks.

Bypass installation: In-line sampling measurement is possible, which is suitable for situations where direct installation in the main process pipeline is not possible.

Confirm during installation:

• Installation location (e.g. reactor, vessel, piping, etc.)

• Mounting method (thread, flange, etc.)

• Installation insertion depth, insulation thickness, whether heat tracing is required

• Whether there is an outer jacket or inner coil structure

3. Determine data output requirements

Viscometers typically offer a variety of data outputs to meet the needs of a process control or monitoring system, common data outputs include:

• Real-time display

• RS-232 or RS-485 serial output (for transmission to computer or PLC)

• 4-20mA signal output (for process control)

• The right type of data output needs to be selected according to the plant's control system for seamless integration into the existing system.

4. Determine the environment and installation needs

(1) Environmental requirements

The installation environment places specific demands on the durability of the viscometer. If it is installed outdoors or in a specific area (e.g. hazardous area), it is necessary to choose equipment with a higher level of protection, such as:

NEMA4 wall-mounted enclosure (for dustproof and waterproof environments)

Explosion-proof enclosures (for areas with hazardous gases)

(2) Cable length

Confirm the cable length from the probe to the viscosity controller to ensure stable signal transmission. In general, the distance between the field measurement and the control system can be met by means of a custom-length cable.

5. Temperature compensation and data correction

In many industrial applications, viscosity varies with temperature. If accurate viscosity data is required, it is recommended to choose a viscometer with temperature compensation to automatically correct the effect of temperature on viscosity to ensure the consistency and accuracy of the data.

6. Choose the right brand and model

According to the actual needs and budget, select the mainstream brands and models in the market, and determine the suitable in-line viscometer by referring to their technical parameters. Common brands provide detailed application examples and support services to help solve problems in installation and commissioning.

In-line viscometer selection is a multi-dimensional decision-making process that takes into account factors such as fluid characteristics, installation methods, environmental conditions, and output requirements. Through these steps, engineers can select the best in-line viscometer for their production line, improving the stability of the measurement and the accuracy of the process control.