Viscosity of a Fluid
Viscosity is the measurement of a fluids internal resistance to flow. It is usually represented in centipoise (cps) or poise (100 Centipose = 1 poise). The higher the viscosity of a liquid, the thicker it is and the greater the resistance to flow; temperature will also affect the viscosity of most materials.
There are several categories of fluid viscosities which include:
Newtonian: At a fixed temperature their viscosity does not change through agitation or pumping. Water and oils are classed as newtonian.
Thixotropic: At a fixed temperature these reduce their viscosity with agitation or pressure increase. Ketchup and mayonnaise are good examples as they appear thick but pump quite easily.
Paste: Some paste viscosity materials will seek their own level or flow slowly. The shorter the time it takes the easier they are to pump. Some do not seek their own level or flow at all and require pressure to move them. To reduce the viscosity of paste materials usually heat is applied. Special consideration needs to be given during the design to ensure they remain at the correct temperature in all stages of the process.
Common Material Viscosities at Various Temperatures (Approximate):
| Liquid | Specific Gravity @ 16°C | Absolute Viscosity cP | Temperature C° | Viscosity Type
N = Newtonian
T = Thixotropic |
|---|
| Cocoa Butter | 0.87 | 0.5 | 100 | N |
| Milk | 1.02-1.05 | 1.0 | 52 | N |
| NaOH 20% | 1.22 | 1.0 | 18 | N |
| NaOH 30% | 1.33 | 1.0 | 18 | N |
| Isopropyl Alcohol | 1.11 | 1.9 | 85 | N |
| Milk | 1.02-1.05 | 2.0 | 18 | N |
| Turpentine | 0.86 | 2.0 | 16 | N |
| Cresol Crystals | | 10 | 18 | T |
| Coffee Liquor 30-40% | | 10-100 | 20 | T |
| Vinegar | | 12-15 | 20 | N |
| Cream 30% Fat | 1.0 | 14 | 16 | N |
| Ethylene | 1.12 | 18 | 21 | N |
| Butter Fat | | 20 | 65 | N |
| Yeast Surry | | 20 | 18 | T |
| NaOH 40% | 1.43 | 20 | 18 | N |
| Sperm Oil | 0.88 | 24 | 38 | N |
| Cotton Seed Oil | 0.93 | 24 | 52 | N |
| Whale Oil | 0.93 | 25-39 | 38 | N |
| Corn Oil | 0.92 | 28 | 57 | N |
| Linseed Oil Raw | 0.93-0.94 | 29 | 38 | N |
| Coconut Oil | | 30 | 38 | N |
| Cod Oil | 0.93 | 32 | 38 | N |
| Diethylene | 1.12 | 32 | 21 | N |
| Castor Oil | | 36 | 80 | N |
| Peanut Oil | 0.92 | 38 | 38 | N |
| Olive Oil | 0.91 | 40 | 38 | N |
| Triethylene | 1.12 | 40 | 21 | N |
| Lard Oil | 0.91-0.93 | 40-47 | 38 | N |
| Butter Fat | | 42 | 43 | N |
| Palm Oil | 0.92 | 43 | 38 | N |
| Butter Deodorised | | 45 | 50 | N |
| Bone Oil | 0.92 | 48 | 54 | N |
| Cream 45% Fat | 0.99 | 48 | 16 | N |
| Latex Emulsion | | 48 | 65 | T |
| Cocoa Butter | 0.92 | 50 | 60 | N |
| Propylene | 1.04 | 52 | 21 | N |
| Cream 50% Fat | | 55 | 32 | N |
| Fruit Juice | 1.04 | 55-75 | 18 | N |
| Coconut Oil | 0.93 | 55 | 24 | N |
| Lard | 0.96 | 62 | 38 | N |
| Cotton Seed Oil | 0.88 | 62 | 24 | N |
| Soya Bean Oil | 0.93 | 60 | 24 | N |
| Edible Oil | 0.9 | 65 | 20 | N |
| Soap Solution | 1.03 at 60°C | 82 | 60 | T |
| Orange Juice Concentrate | 30 Brix | 91 | 80 | N |
| Gravy Slurry | 1.0 | 110 | 80 | T |
| Sulphonic Acid | 1.04 | 125 | 30 | T |
| Whole Egg | | 150 | 4.5 | T |
| Yoghurt | 1.15 | 152 | 40 | T |
| Tomato Paste 30% | | 195 | 18 | T |
| Sorbitol | 1.29 | 200 | 20 | N |
| Latex Emulsion | 1.0 | 200 | 24 | T |
| Chocolate | | 280 | 49 | T |
| Pectin | | 300 | 38 | N |
| Chinawood Oil | 0.94 | 300 | 21 | N |
| Pectin | | 345 | 27 | N |
| Brewers Yeast | | 368 | 18 | T |
| Broth Mix | | 430 | 18 | T |
| Sauce – Apple | 1.1 | 500 | 80 | T |
| Wax | 0.9 | 500 | 93 | T |
| Castor Oil | 0.96 | 580 | 27 | N |
| Citrus Fruit Pulp | 1.27 | 600 | 20 | T |
| Soap Arylan | 1.0 at 40°C | 630 | 60 | T |
| Orange Juice Concentrate | 30 Brix | 630 | 20 | N |
| Glycerine 100% | 1.26 at 20°C | 648 | 20 | N |
| Printers Ink | | 238-660 | 54 | T |
| Hand Cream | | 780 | 18 | T |
| Resin Solution | | 880 | 24 | T |
| Resin Solution | | 975 | 21 | T |
| Tomato Ketchup | | 1000 | 30 | T |
| Gelatine 37% Solids | | 1190 | 43 | T |
| Mousse Mix | | 1200 | 5 | T |
| Acetate Glue | | 1200-1400 | 20 | T |
| Baby Food | | 1400 | 93 | T |
| Detergents | | 1470 | 70 | T |
| Carob Bean Sauce | | 1500 | 30 | T |
| Custard | 1.6 | 1500 | 85-90 | T |
| Beet Sauce | | 1950 | 76 | T |
| Condensed Milk 75% Solids | 1.3 | 2160 | 20 | T |
| Orange Juice Concentrate | 50 Brix | 2410 | 20 | N |
| Salad Cream | | 1300-2600 | 18 | T |
| Malt Extract | 1.4 | 3000 | 60 | T |
| Paraffin Emulsion | 1.2 | 3000 | 18 | T |
| Shampoos | | 3000 | 36 | T |
| Lacquer 25% Solids | | 3000 | 18 | T |
| Polyester | 1.1 at 30% | 3000 | 30 | T |
| Glucose | 1.3 | 4300-8600 | 25-30 | T |
| Soya Bean Slurry | | 5000-10,000 | 50-90 | T |
| Process Cheese | | 6500 | 80 | T |
| Resin Solution | | 7140 | 18 | T |
| Jam Garnish | | 8440 | 16 | T |
| Malt Extract 80% | | 9500 | 18 | T |
| Rice Pudding | | 10,000 | 100 | T |
| Polyisobutylene | 1.09 at 85° | 12,500 | 85 | T |
| Mayonnaise | | 20,000 | 20 | T |
| Condensed Milk | | 40-80 | 40-50 | N |
| Orange Juice Concentrate | 50 Brix | 330 | 80 | N |
| Plastisol | 2.5 | 28,000 | 18 | T |
| Biscuit Cream Premix | | 29,200 | 18 | T |
| Batter | | 29,500 | 30 | T |
| Cottage Cheese | | 30,000 | 18 | T |
| Process Cheese | | 30,000 | 18 | T |
| Triacetate Dope | | 48,000/60,000 | 40 | T |
| Toothpaste | | 70,000-100,000 | 18 | T |
| Mincemeat | | 100,000 | 30 | T |
| Polypropylene | | 240,000 | 50 | T |