Say Something about Viscosity Testing

Hello Anyone who read this article.

I write this article because i have received many question about how to operate our machine.

Why need viscosity testing.

What can viscometer do.

Let’s learn something first.

What is viscosity?

The viscosity of a fluid is the measure of its resistance to gradual deformation by shear stress or tensile stress.-------Wikipedia

 

What is Ubbelohde viscometer?

An Ubbelohde type viscometer or suspended-level viscometer is a measuring instrument which uses a capillary based method of measuring viscosity.

A liquid is introduced into the reservoir then sucked through the capillary and measuring bulb. The liquid is allowed to travel back through the measuring bulb and the time it takes for the liquid to pass through two calibrated marks is a measure for viscosity.

The Ubbelohde device has a third arm extending from the end of the capillary and open to the atmosphere. In this way the pressure head only depends on a fixed height and no longer on the total volume of liquid.-------Wikipedia

Why testing viscosity?

Gathering viscosity data on a material gives manufacturers the ability to predict how the material will behave in the real world. For example, if toothpaste does not have the correct viscosity, it can either be too difficult to pump out from the tube, or pump out too much. 

Knowing the viscosity of a material also affects how the production and transportation processes are designed. 

Newtonian and Non-Newtonian fluids.  

Isaac Newton, the man to discover this formula, thought that, at a given temperature and shear stress, the viscosity of a fluid would remain constant regardless of changes to the shear rate. 

He was only partly right. A few fluids, such as water and honey, do behave this way. We call these fluids Newtonian fluids. Most fluids, however, have viscosities that fluctuate depending on the shear rate. These are called Non-Newtonian fluids.

There are five types of non-Newtonian fluids: thixotropic, rheopectic, pseudoplastic, dilatant, and plastic. Different considerations are required when measuring each of these fluid types.

How many accessories required for Viscosity testing?

Simple, follow the stander.

For example, if we testing the PET viscosity, we following the stander GB 17931 or GB/T 14190 or ASTM D4603 or ISO 1628-5.

All the details and progress were listed on the stander.

Take GB 17931 for example,it’s process as following:

I have oranisged the accessories list as below.

Instruments and Solvent for PET Viscosity Measuring Project
Prepare the sample			Function
	Stander
Sample Bag	12cm*17cm（Suggest）		Prepare the sample
Prepare the sample
	Stander
Sessior	11.5cm Scissors		cut sample small for dissolving
Sample Preparation
	Stander
Analytical Balances	Precision 0.1mg		Sample weighing
Dissolving Bottle	50ml or 100 ml Volume	Based on ISO1042 stander，With ground glass stopper	Hold sample and solvent
Weighing paper	120mm*120mm（Suggest）
Conical flask	100ml
Pipette	25ml		Transfer fix volume liquid
Filter appliance	Sand core funnel	40um～100um diameter or Stainless steel mesh plug，0.075mm2	Filter impurities
Sample Dissolving	Temp range 0～120℃		Dissovling the sample
Electric blast drying box			Drying flask with
Vacuum drying oven	Pressure＜100kPa		If the sample moisture exceeds the standard for drying
Solvent
Weight 1:1 or 3:2 phenol/tetrachloroethane solution, accurately weighed at least 1%.			The density ranges are 1.280 ± 0.003 g/cm3 and 1.235 ± 0.003 g/cm3, At 25 degrees ± 0.02
Water
Chromic acid lotion			cleaning the ubbelohde tube
Glass bottle	Brown，5000ml		solvent storage
Dryer and silicone			Hold stander PET chips
Ethanol	AR Stander		Cleaning and dry the tubes
Phenol	AR Stander
Tetrachloroethane	AR Stander
Ear wash ball
Environment Required
	Stander
Fume hood	able acid and alkali corrosion resistance		Toxic and hazardous reagents must be operated in a ventilated environment
Air conditioning			The experimental environment should be controlled at 25°C
Tips: the reagent having toxicity test method should avoid contact with skin and inhalation of vapors.                                                                                     Operators should take appropriate safety and health precautions.

How to choose the viscometer?

First,know what sample you are going to test? It’s it PET or Food?

Our viscometer only applied to test the viscosity of Newtonian liquid

How to use the viscometer？

For more details,please refer to our YouTube Video.

https://www.youtube.com/watch?v=QgPfbsyvHxQ&t=59s

For more details,please feels free to contact.

Kent

lei@zonwon.com

WhatApp/Wechat: +86 13388604020