New Viscometry: The Top 10 Benefits for Kinematic Viscosity Measurements

They protect your engine. They ensure safe brakes. They secure smooth gear shifts. They cool down the heat.
Every time you drive. What are they? They are the operating fluids of your car.

In a motor vehicle, the term “powertrain” describes the main components that generate power and deliver it to the road surface, water, or air.
This includes the engine, transmission, drive shafts, differentials, and the final drive (drive wheels, continuous track as in military tanks or caterpillar vehicles, etc.). In this context, the term “operating fluids” refers to fluids that comprise products designed to aid the operation of a vehicle, such as engine oil, gearbox oil, transmission fluids, etc. However, for a motor vehicle producer there are more liquids to be tested, including brake fluids, coolants, and also fuels.

Nowadays, fuel economy is becoming more and more important and the viscosity of the oils is getting lower and lower.
It is of great importance that the viscosity remains stable during the whole oil drain interval.

MAN Truck & Bus AG is one of the leading manufacturers of diesel motors for heavy duty vehicles. The MAN Department for Applied Chem.
Operating Fluids has been relying on Anton Paar’s SVM for many years now.

Innovation in Viscosity Determination: SVM™ Stabinger Viscometer™ Series

The highly precise viscometers of the SVM™ series are based on a rotational measuring principle and have an integrated density measuring cell. The small viscosity measuring cell contains a tube which rotates at a constant speed and is filled with sample fluid. A measuring rotor with a built-in magnet floats freely in the sample. The sample’s shear forces drive the rotor while magnetic effects retard its rotation. Shortly after the measurement starts, the rotor reaches equilibrium speed. This speed is a measure of the fluid‘s viscosity (Fig. 1).

Figure 1: Stabinger Viscometer™ measuring principle

As the density cell of SVM™ is integrated, the density measurement does not have to be carried out separately. In fact, one combined measuring cell covers the entire measuring range for viscosity, density, and temperature and is filled in one go. A minimum sample amount of only 1.5 mL is sufficient for multiparameter results in one fast measurement.

Here are 10 reasons why MAN Department for Operating Fluids relies on SVM™ 3001

Measuring Range

What if a sample outside the “usual” viscosity range needs to be measured from time to time? What if mostly lubricating oils are measured, but sometimes a diesel or bio-diesel sample comes in? Or in some instances the temperature of -20 °C is of interest and no circulation cooler is available?
All these scenarios are no problem for SVM™. One combined measuring cell of SVM™ 3001 covers the entire measuring range for viscosity, density, and temperature and is filled in one go. The viscosity measuring range of the cell is from 0.2 mm²/s to 30 000 mm²/s, whereby the temperature range is from -60 °C to +135 °C (-20 °C is reached without external cooling). This measuring range allows for measuring a wide range of samples of different viscosity with one integrated measuring cell. Furthermore, in combination with very fast heating and cooling rates as well as the powerful temperature scans it opens new possibilities in lubricating oil testing.

Fast Heating/Cooling Rates

With traditional bath systems for temperature control, the user normally needs to decide on the measuring temperature and never change this temperature 24/7 – until the next scheduled maintenance. This is drastically different with SVM™.

SVM™ 3001 has very fast heating/cooling rates of up to 20 °C/min. Such fast temperature changes allow for extraordinary flexibility when choosing the samples, measuring temperatures, and tests that need to be performed. With the small sample volume as low as 1.5 mL (for both viscosity and density determination) not only temperature changes but also thermal uniformity is rapidly achieved. The direct thermo-electric cooling by Peltier elements provides very sensitive and fast control of the cell temperature. So, after entering a new set temperature, it takes only a few minutes for the instrument to be ready for the next test.

With built-in air cooling, SVM™ 3001 can reach -20 °C without the need for any thermal transfer liquids or external devices.

The True Value of Temperature Scans

Have you ever been able to perform a kinematic viscosity scan in order to examine the behavior of your sample over a temperature range? Or perhaps you are interested in both viscosity and density values at different temperatures, but would prefer to obtain the values in one simple measurement? Here is how.

As fuel economy and long drain intervals are the most important requirements for trucks and buses, when developing engines the analysis of the oil is very important. One of the most important parameters is the viscosity of the oil – at different temperatures. Therefore, a temperature scan is very helpful for the construction engineers to do calculations of the bearings in order to ensure that enough protective film is available. After one injection of the sample via syringe, SVM™ 3001 can run a temperature table scan from -20 °C to +130 °C in 10 °C steps. Since SVM™ 3001 does not need any external cooling to reach -20 °C, the entire measurement is done with one stand-alone instrument in a simple manner. All data are available about 1h 25 min after the start of the scan and no operator attendance is needed in the meantime. Measurement values for kinematic viscosity are obtained, but also for dynamic viscosity and for density – all in one graph (Figures 2 and 3).

Fig. 2 Temperature scan graph


Fig. 3 Table temperature scan

Integrated Density Measurement

Due to the density oscillator integrated in SVM™, the density measurement according to ASTM D4052 or ISO 12185 is carried out simultaneously with the viscosity measurement. In other words, the density thermal coefficient of the current sample is a measured value instead of the typical value for the product group. This offers various possibilities and hence flexibility. Since density at 15 °C or 20 °C is commonly needed, a temperature table scan can be set up with the required temperatures (i.e.15 °C, 40 °C, 100 °C) as shown in Fig. 4. Another possibility would be API calculations of density over temperature, which are integrated in the instrument software and are freely selectable on the 10.4” touchscreen.

Fig. 4 Kinematic viscosity, density and VI values of various operating fluids

Viscosity Index Reloaded

Do you need Viscosity Index determination but are also interested in the density value at 15 °C? Do you need Viscosity Index but would rather measure at 40 °C and 80 °C? No problem.
In the automatic Viscosity Index mode of SVM™ 3001, temperature changes are performed automatically and the Viscosity Index is calculated in compliance with ASTM D2270. Typically, the measurements are performed at 40 °C and 100 °C, but since viscosity-temperature extrapolations according to ASTM D341 are integrated in the instrument software, the measurements can also be performed at two different temperatures and the Viscosity Index automatically calculated. The benefit of this measurement is that the actual density of the lubricating oil at both temperatures, 40 °C and 100 °C, is also measured. This means that the extrapolation of the density from these two points (lying far apart) is precise. It is sometimes also referred to as a “density-temperature slope”. For the lubricating oils tested, the extrapolations error was found to be lower than 0.0001 g/cm3.

Low Sample Volume

At MAN, used oils from the field are sometimes also sent in to be tested, as changes in the oil’s viscosity can reveal oil thinning due to fuel dilution or oil aging. In such cases often only a low sample volume is available, but a number of different tests need to be performed in the laboratory. This is why the low sample volume required for a multiparameter determination with SVM™ is very beneficial. The minimum sample volume required for SVM™ 3001 is only 1.5 mL; typical sample volume amounts to approximately 5 mL.

Low Solvent Volume

Are you interested in lowering not just solvent costs, but also the costs of the solvent disposal? With the small cell of the new SVM™, the cleaning requires low solvent amounts. At MAN this means a fraction of waste liquid is produced compared to the amount produced when using traditional methods.

Ready to Use Out-of-the-Box

SVM™ requires no complicated or time-consuming installation. No liquids need to be filled, no complex putting into service is required.
SVM™ 3001 is factory-adjusted and ready for immediate use. Just unpack it, plug it in, and switch it on.

Unbeatable Ease of Operation

Fill in the sample via syringe and press start. SVM™ is arguably the easiest-to-use kinematic viscometer in the world and gives you accurate multiparameter results within minutes. An intuitive 10.4” touchscreen with state-of-the-art PCT technology allows for easy and instantaneous selection of multiple parameters and API calculations. 

Flexibility in Measurements

What can the wide measuring range, fast heating/cooling rates, and multiparameter measurements do for you?  Having the flexibility to measure various samples with different viscosities at various temperatures with one measuring cell is perhaps one of the most striking advantages of SVM™ 3001. You do not need to worry about changing the capillaries (for a different viscosity range) or long heating-up or cooling down times to equilibrate to a new measuring temperature. You do not need to choose one measuring temperature and stick with it. You can choose the Viscosity Index mode and right after that set up a temperature table scan over a wide temperature range. You can get viscosity, density, API calculations of density over temperature, Saybolt Viscosity, Viscosity Index – and more – in one measurement. Also, you have the flexibility to choose from extremely fast, but somewhat less precise measurements for “difficult” samples, or highly precise measurement criteria. You now have a tremendous flexibility in your measurements – for the most efficient analysis of your sample.

Are you interested in the SVM™ Stabinger Viscometer™ Series?

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