Robotic Viscometer Aids in Oil Service Lab Processing

Curtis Felix, Cambridge Viscosity; Jonathan Cole, Cambridge Viscosity

A typical testing service laboratory, QC or R&D lab can process up to hundreds of viscosity samples a day. The lab may support the research and development of new products, test samples directly off a production line or provide in-service lubricant testing.

To meet these demands, manufacturers are developing automated equipment to improve productivity and sample process quality. For example, the Cambridge VISCObot is designed to seamlessly integrate into a company’s current operating practices.

Through automation, the VISCObot provides a test methodology controlled by software which maximizes the effectiveness of laboratory personnel and ensures consistency - from operator to operator and test to test.

To meet the growing demands for viscosity measu`rement, Cambridge Viscosity has developed a unique flexible tool that is beneficial for any laboratory. Utilized in a high-volume lab or in multistage screening and evaluation, the VISCObot helps customers succeed by:

  • fully automating viscosity testing
  • reducing sample process labor
  • reducing time to market
  • improving formulations
  • increasing operator flexibility

In-service Lubricant Testing

As a result of education and awareness, there is a growing demand for in-service lubricant testing. Many companies are starting their own in-house programs and/or outsourcing an increased fluid testing load.

Traditional laboratory instruments are labor-intensive, and according to recent independent interlaboratory round-robin data, are surprisingly less consistent than what is expected from traditional test methods.

This is not unexpected due to the extraordinary demands labs face today and the heavy reliance on human factors in most viscosity testing. VISCObot is a new approach to eliminating sample handling and the need for filling, cleaning or processing results. In addition, the fully automated method provides extensive statistical process control to ensure a higher level of consistency.


The expansion of specialty lubricants has increased demand for improved products. One leading chemical manufacturer faced the combined challenge of producing new and innovative products while lowering material and production costs.

The manufacturer was interested in improving formulations up to 50 cP (centipoise). The desired performance characteristics included the ability to evaluate hundreds of samples a day with an appropriate accuracy and repeatability to support efforts in screening and formulation work.

The company’s tests indicated a number of important characteristics from the VISCObot Robotic Viscometer. Specifically, the VISCObot:

  • Offers unattended operation with high throughput of less than five minutes, including sampling, measuring and cleaning.

  • Frees up valuable lab technician hours, saving money in viscosity tests.

  • Eliminates operator dependence by making the results systematically repeatable, statistically verified and therefore more robust for meeting continuous improvement objectives.

  • The Cambridge VISCObot showed accuracy of ±2 percent of reading for water based fluids and ±3.5 percent for solvent-based fluids.

  • Requires a sample size of 5 mL per measurement.

  • Works effectively with water and various solvents including methyl ethyl ketone.

  • Uses a flexible and reliable sampler that accepts trays of up to 200 samples and can be adjusted to different sampling bottles or tray layouts.

Multistage Formulation

New product development is turning into a numbers game. Successful companies will be able to efficiently identify the most promising catalysts and chemicals with minimal effort or resources. Users are gravitating to a multiphase approach, which places different demands on instrumentation.

First Stage

High-throughput screening is the first method used to identify significant differences in the desired product parameters. Detailed analysis on all formulations is impractical. Screenings use a minimum number of tests enhanced by sophisticated tools to speed up the process. At this stage, the accuracy of the instrument is typically not as critical as appropriate evidence of the targeted characteristic, sample usage and throughput time.

Second Stage

Once the number of potential formulations decreases from the thousands to a few hundred, further analysis is necessary. Candidate formulations undergo detailed tests that require larger sample sizes and more precise performance analysis.

Despite the improved performance characterization, 80 to 90 percent of the formulations will not make it out of this stage. Controlling the time spent examining each of these leads is essential. Test accuracy of two to three percent provides enough sensitivity to identify the best formulations. Tests are often performed in replicate to estimate repeatability and guard against errors.

Third Stage

The third level of high-throughput screening frequently involves the final 10 to 15 formulations. These finalists undergo detailed evaluations and are scrutinized for desired performance characteristics. The goal of this testing is to determine if any of the samples should be recommended for further development or pilot production. The primary analysis concerns for measurements at this stage are accuracy and repeatability; test time and sample size are of less significance.

Cambridge Viscometers

Cambridge viscometers are fundamentally simple, robust, accurate and repeatable with an easy user interface. A key to the company’s technology is its use of single, noncontact moving parts for measuring and cleaning. Piston motion is controlled to monitor the fluid viscosity and ensure the sensor’s measurement chamber remains clean, requiring minimum operator attention.

A temperature detector is also included in the measurement chamber, which allows both temperature and viscosity to be available for every measurement. The company’s patented self-cleaning and self-recovery characteristic enables the Cambridge sensors to operate trouble-free for in-line or in-laboratory applications.

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