Let's take a look at the classification of viscometers

A viscometer is an instrument used to measure the viscosity of fluids (liquids and gases)
.

Viscosity is a physical quantity that indicates the internal friction inside the fluid when the fluid is flowing.
It is the ability of the fluid to resist deformation.
It is an important indicator used to identify some finished or semi-finished products
.

Viscosity varies from fluid to fluid and varies with temperature
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There are mainly three types of capillary viscometers, rotational viscometers and falling ball viscometers
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When a liquid is flowing, the property of internal friction between its molecules is called the viscosity of the liquid.
The viscosity is expressed by viscosity, which is a resistance factor used to characterize the properties of the liquid
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The viscosity of insulating oil is the same as that of general liquid, that is, the internal friction of the liquid, that is, when the insulating oil moves relative to laminar flow under the action of external force
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The properties of insulating oil molecules that generate internal frictional resistance
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The greater the internal friction of the insulating oil, the greater the viscosity, the more difficult the flow, and the poorer heat dissipation performance
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According to the operation mode, there are 3 types: capillary type, rotary type and vibration type
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Capillary Viscometer: A capillary viscometer is usually a Saybolt viscometer, which is a common viscometer
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Its working principle is: the sample container (including the outflow capillary) is filled with the sample to be tested, and it is in a constant temperature bath, and the height of the liquid column is h
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Open the cock, the sample begins to flow to the liquid receiver, and the time is calculated until the sample liquid level reaches the mark
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The more viscous the sample, the longer this period of time
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Therefore, this time directly reflects the viscosity of the sample
.

Rotational viscometer: A common rotational viscometer is the cone and plate viscometer
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It mainly includes a flat plate and a cone plate
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The motor drives the plate to rotate at a constant speed through the variable speed gear, and the sample to be tested is kept between the two plates by capillary action, and the friction between the sample molecules drives the cone to rotate
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Under the action of the torsion spring in the torque detector, the cone and plate no longer rotate after the angle of rotation
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At this time, the torque exerted by the torsion spring is related to the internal molecular friction (ie viscosity) of the tested sample: the greater the viscosity of the sample, the greater the torque
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There is a variable capacitor in the torque detector, and its moving piece rotates with the cone and plate, thereby changing its own capacitance value
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The torsion spring torque reflected by this capacitance change is the viscosity of the tested sample, which is displayed by the meter
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Vibration viscometer: The working principle of this viscometer is that when the object in the fluid vibrates, it will be hindered by the fluid, and the magnitude of this effect is related to the viscosity of the fluid
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Commonly used vibrating viscometers are ultrasonic viscometers, which have a shrapnel in the detector
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When excited by a pulsed current, the shrapnel produces mechanical vibrations in the ultrasonic range
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When the shrapnel is immersed in the sample to be tested, the amplitude of the shrapnel is related to the viscosity and density of the sample
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With a known density, the viscosity value can be derived from the measured amplitude data
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