Here are the six types we'll cover:
Orifice Viscometer
Capillary Viscometer
Drop Piston Viscometer
Rotational Viscometer
Falling Ball Viscometer
Vibration Viscometer
#1 — Orifice Viscometer
Orifice plate viscometers usually consist of a cup with a hole through which a fluid flows. Viscosity is determined by timing the time it takes for the cup to empty and is measured in cup seconds. Orifice plate viscometers are easy to use manually thanks to the fact that they only need to be immersed in the fluid being processed - making them popular in the coatings industry. They include Zahn Cups, Ford Cups and more.
#2 — Capillary Viscometer
Also known as U-tube viscometers, capillary viscometers include Ostwald and Ubbelohde variants. They are simple to use and consist of a U-shaped glass tube with two bulbs (one high and one low). Fluid flows from the upper sphere to the lower sphere through capillary tubes, and viscosity is measured by timing the time it takes the fluid to travel through the tube.
#3 — Falling Piston Viscometer
According to Wikipedia, falling piston viscometers were invented by Austin Norcross, which is why they are also called Norcross viscometers. They function by drawing the fluid being measured into the piston cylinder as the piston rises; the time it takes the piston to fall (fall time seconds) due to the resistance of the fluid is used to determine viscosity. Falling piston viscometers are easy to use and maintain, and offer long product life.
#4 — Rotational Viscometer
Rotational viscometers measure viscosity by immersing a rotating spindle in the fluid being measured. The power (torque) required to turn the spindle indicates the viscosity of the fluid, and since Rotational Viscometers do not use gravity to act, their measurements are based on the internal shear stress of the fluid.
#5 — Falling Ball Viscometer
A falling ball viscometer works in a similar way to a falling piston viscometer. With this type of viscometer, a ball is dropped into a sample of the fluid being measured. The dimensions of the ball are known, so the viscosity depends on the time it takes for the ball to fall through the fluid by gravity (again, using the fall time in seconds).
#6 — Oscillating Viscometer
A vibrating viscometer uses a powered vibrating rod to measure viscosity. Different fluids are more or less resistant to vibrations depending on their viscosity. Thus, by measuring the decay of the vibration, or by measuring the rate at which the vibration of the viscometer decays, the viscosity can be determined. Vibrating viscometers are very popular because of their high sensitivity and no moving parts.
