Lobe Pump Overview

Lobe pumps are used in a variety of industries including, pulp and paper, chemical, food, beverage, pharmaceutical, and biotechnology. They are popular in these diverse industries because they offer superb sanitary qualities, high efficiency, reliability, corrosion resistance, and good clean-in-place and sterilize-in-place (CIP/SIP) characteristics.

Rotary lobe pumps range from industrial designs to sanitary designs. The sanitary designs break down further depending on the service and specific sanitary requirements. These requirements include 3-A, EHEDG, and USDA. The manufacturer can tell you which certifications, if any, their rotary lobe pump meets.

These pumps offer a variety of lobe options including single, bi-wing, tri-lobe, and multi-lobe. Rotary lobe pumps are non-contacting and have large pumping chambers, allowing them to handle solids such as cherries or olives without damage. They are also used to handle slurries, pastes, and a wide variety of other liquids. If wetted, they offer self-priming performance. A gentle pumping action minimizes product degradation. They also offer reversible flows and can operate dry for long periods of time. Flow is relatively independent of changes in process pressure, so output is constant and continuous.

How Lobe Pumps Work

Lobe pumps are similar to external gear pumps in operation in that fluid flows around the interior of the casing. Unlike external gear pumps, however, the lobes do not make contact. Lobe contact is prevented by external timing gears located in the gearbox. Pump shaft support bearings are located in the gearbox, and since the bearings are out of the pumped liquid, pressure is limited by bearing location and shaft deflection.

lobe pump diagram

As the lobes come out of mesh, they create expanding volume on the inlet side of the pump. Liquid flows into the cavity and is trapped by the lobes as they rotate.
Liquid travels around the interior of the casing in the pockets between the lobes and the casing -- it does not pass between the lobes.
Finally, the meshing of the lobes forces liquid through the outlet port under pressure.

Lobe pumps are frequently used in food applications because they handle solids without damaging the product. Particle size pumped can be much larger in lobe pumps than in other PD types. Since the lobes do not make contact, and clearances are not as close as in other PD pumps, this design handles low viscosity liquids with diminished performance. Loading characteristics are not as good as other designs, and suction ability is low. High-viscosity liquids require reduced speeds to achieve satisfactory performance. Reductions of 25% of rated speed and lower are common with high viscosity liquids.

Advantages

Pass medium solids
No metal-to-metal contact
Superior CIP/SIP capabilities
Long term dry run (with lubrication to seals)
Non-pulsating discharge

Disadvantages

Requires timing gears
Requires two seals
Reduced lift with thin liquids

Applications

Common rotary lobe pump applications include, but are not limited to:

Polymers
Paper coatings
Soaps and surfactants
Paints and dyes
Rubber and adhesivesPharmaceuticals
Food applications (a sample of these is referenced below)

Food and cosmetic products capable of being pumped by lobe rotor pumps.

From Dickenson, T. C. 1995. Pumping Manual, 9th Ed. Elsevier Advanced Technology:

Alcohol

Apple purée

Apricots

Baby food

Batter

Beans

Beer

Beetroot

Biscuit Cream

Blackcurrants

Brine

Broth

Butter fat

Caramel

Castor Oil

Cat food

Cheese curd

Cheese whey

Cherries

Chicken paste

Chili con carne

Chocolate

Chutney

Cockles

Coconut oil

Cod oil

Coffee liquor

Cordials

Corn oil

Corn syrup

Cottage cheese

Cotton seed oil

Cranberry juice

Cream

Cream cheese

Custard

Dog food

Dough

Eggs - whole

Egg yolk

Essences

Evaporated milk

Fish

Flavorings

Fondants

Fruit juice

Fruit pulp

Fruit - whole

Fruit yogurt

Gelatin

Gherkins

Glucose

Glycerin

Gooseberries

Gravy

Hand cream Honey

Horseradish

Ice cream

Icings

Iodine ointment

Jams

Jelly

Ketchup

Lard

Liquid sugar

Lotions

Malt

Maple syrup

Margarine

Marmalade

Marshmallow

Marzipan

Mascara

Mayonnaise

Milk

Mincemeat

Molasses

Mousse

Mussels

Mustard

Nail polish

Nail varnish

Offal

Olive oil

Onions

Palm oil

Pastes

Peanut butter

Pectin

Perfumes

Piccalilli

Pie fillings

Pizza toppings

Plasma

Potato salad

Preserves

Purées

Quinine

Rice pudding

Salad dressing

Shrimps Soap

Solvents

Sorbitol syrup

Soup

Soya sauce

Spirits

Starches

Stews

Strawberries

Sugar

Syrup

Tapioca

Tea

Tomato ketchup

Tomato paste

Tomato purée

Toothpaste

Vaseline

Vegetables

Vinegar

Water

Wines

Wort

Yeast

Yogurt

Materials of Construction / Configuration Options