How To Choose A Rotor For A Rotational Viscometer
Selection of a rotational viscometer spindle usually depends on the nature of the sample to be measured and the expected measurement range. Different types of rotors are suitable for different types of liquids or slurries. Here are some common rotational viscometer spindle types and their suitability:
1. Rotating ball rotor (Spheres): suitable for most fluids, especially in the medium to high viscosity range. The diameter of the ball is often used to adjust the measuring range.
2. Blade rotor (Spindles): There are blades of various shapes and sizes, suitable for samples with different viscosity ranges. Smaller blades are suitable for low viscosity liquids, while larger blades are suitable for high viscosity liquids.
3. Conical rotor (Cones): suitable for high viscosity liquid or slurry. The conical rotor provides greater shear force and is suitable for measuring high-viscosity samples, such as colloids, glues, etc.
4. Cup rotor (Cups): suitable for measuring the viscosity of liquids, especially the surface tension of liquids. Cup rotors are often used to measure the viscosity of liquids such as paints and greases.
5. Cylindrical rotors (Cylinders): suitable for the measurement of non-flowing samples such as powders, granules, and colloids.
When selecting a spindle, you need to consider the characteristics of your sample (e.g. viscosity, particle size, flowability, etc.) and the required measurement range.
Common rotor numbers:
The choice of spindle number for a rotational viscometer usually depends on the nature and viscosity range of the sample to be measured. Different rotor numbers represent different rotor sizes and shapes, suitable for different ranges of viscosity measurements. Here are some common rotor numbers and their applicability:
1. #1 Spindle: Suitable for lower viscosity range, usually used for liquid samples, such as water samples.
2. #2 Spindle: Suitable for medium viscosity range, often used to measure samples like solutions and coatings.
3. #3 Spindle: Suitable for higher viscosity range, suitable for slurry and colloidal samples.
4. #4 Spindle: Suitable for very high viscosity ranges, typically used for slurries, colloids and non-flowing liquids.
5. #5 Spindle: For extremely high viscosity samples such as pasty or semi-solid materials.
6. 0# rotor: It is suitable for the measurement of many medium to high viscosity liquids and is one of the relatively commonly used rotors. The following are sample types suitable for using 0# rotor:
a. Liquid coatings and paints: 0# rotor is often used to measure the viscosity of liquid coatings and paints. Samples of this type typically have medium to high viscosity.
b. Resin and glue: Liquid resin and glue usually have relatively high viscosity and are suitable for measurement with the 0# rotor.
c. Cosmetics: Certain cosmetic products, such as lotions, creams and cosmetic bases, usually fall into the medium viscosity range and are suitable for testing with the 0# spindle.
d. Food and beverages: For example, food products such as jam, syrup, honey, and some thick beverages can use the 0# rotor for viscosity measurement.
e. Chemicals: Some chemicals, such as solutions, certain colloidal solutions, etc., can be measured using the 0# rotor.
A sample adapter is an accessory for a rotational viscometer that is typically used to measure samples with less viscosity, or when only a small amount of sample is available. Small sample adapters can help ensure accurate viscosity measurements with small sample volumes.
Sample adapters are suitable for the following types of samples:
1. High viscosity samples: When dealing with high viscosity liquids or slurries, usually only a small amount of sample is required for testing. Sample adapters can help obtain accurate viscosity data with small sample volumes.
2. Explicit non-Newtonian fluids: The viscosity of some liquids changes significantly when shear force is applied. This phenomenon is called non-Newtonian fluids. Sample adapters are available for testing this type of fluid, providing accurate rheological data.
3. Limited sample size: In some cases, such as in the pharmaceutical industry or laboratory research, the number of samples may be very limited. The sample adapter ensures minimal sample use and still enables accurate viscosity measurements.
4. Samples with high accuracy requirements: For samples that require extremely high measurement accuracy, using a sample adapter can help reduce the sample volume, thereby improving the accuracy of the test.