Accurate drop size is an important

factor in the overall effectiveness

of spray nozzle operation. The

process of generating drops is

called atomization. The process of

atomization begins by forcing

liquid through a nozzle. Numerous

types of nozzles with different

shaped orifices produce various

spray patterns.

Figure 2

Liquid spraying systems typically

use V-jet, flood-jet or atomizing

nozzles to disperse the sprayed

Liquid.

The potential energy of the liquid

along with the geometry of the

nozzle causes the liquid to emerge

as small ligaments. These liga-

ments then break up further into

very small “pieces”, which are

usually called droplets.

Many of the products we use every

day are manufactured using sprays

in the product mix. These range

from cleaning products to snacks.

Sprays are often introduced dur-

ing the mixing phase of process-

ing.

While ingredients are being mixed

within the trough of an industrial

processing mixer, spraying sys-

tems may be applied to form parti-

cles and coat ingredients for a

wide array of applications.

Some examples and key technical

issues are as follows:

Atomization of viscous

feedstock’s for spray drying

to make dry laundry granules

and instant coffee.

Key issues: Particle-size dis-

tribution and morphology.

Coating of laundry detergent

tablets and powders.

Key issues: Proper dosing

without overspray.

Atomization of dyes, per-

fumes and liquid binder to dry

laundry particles.

Key issues: Proper drop size

and spray pattern.

Atomization of melts to form

aesthetic pills.

Key issues: Proper drop size

and spray pattern.

Figure 1

Integrally mounted injection mani-

fold systems as pictured in Figure

1 may be used to incorporate liq-

uids, gases and shortening to many

different product applications in

the Food, Plastic, Chemical and

Mineral Industries. The spray

manifold is properly distanced

from the material bed surface,

which ensures even distribution of

liquids or gases added to mixtures.

Spray systems consist of piping,

pumps and spray nozzles. Spray

nozzles, Figure 2 are precision

components designed to yield very

specific performance under very

specific conditions. Just because a

nozzle is spraying doesn’t mean it

is working properly.

Sprayed liquids have a wide range

of fluid properties, many of which

are highly viscous and contain

high fraction of solids. Viscosity

refers to "thickness". Thus, water

is "thin", having a lower viscosity,

while vegetable oil is "thick" hav-

ing a higher viscosity.

Liquid Sprays in Consumer Product Manufacturing

February 2011

Special points of

interest:

Liquid Spray System

Applications

Pumping Systems

CIP/SIP Systems

Controlling

Agglomeration

Optimization &

Automation

Case Studies

Inside This Study:

Liquid Sprays &

Consumer Products

1

Choosing the Right

Pumping System

2

CIP/SIP Systems 3

Control Agglomerates

Adjusting Spray

3

Multiple Processes in

One Mixer

3

Optimization and

Automation

4

Liquid Spray

Application Gallery

5

Liquid Spray Mixing

Systems

Combining Mixing & Liquid Spray Application

Case Studies 5

Other Resources 5

Having an effective pumping

system is essential to the overall

performance of the spraying

system. It’s important to con-

sider your pressure requirements,

flow rate and environment, espe-

cially with hard-to-handle fluids

like corrosives, viscous, shear-

sensitive or abrasive slurries.

With many types of different

spray ingredients come many

types of different pumps suitable

to the application. Some exam-

ples include: peristaltic, slurry,

air-operated, diaphragm, high

pressure and piston-type pumps.

Peristaltic Pumps - A common

pump used in many mixing ap-

plications is the peristaltic

(figure1). Peristaltic pumps are

typically used to pump clean/

sterile or aggressive fluids, be-

cause cross contamination can-

not occur. The fluid is contained

within a flexible tube fitted in-

side a circular pump casing.

These pumps are often referred

to as a hose or tube pump.

They are designed to pump liq-

uids containing particles and can

handle high solid slurries, ag-

gressive chemicals, shear-

sensitive products and products

with high viscosities and densi-

ties. For Example:

Snack Food Processing

Snack food processors often use

metered flavorings where a vari-

ety of powdered flavorings are

blended with oil and pumped

into special spray nozzles onto

snack products mixed inside a

paddle mixer. With low shear

pumping action and the ability to

totally enclose the pumped

media within the tube, his en-

sures optimum levels of hygiene

and product integrity. Also the

ability to sustain volumetric

accuracy, irrespective of changes

in viscosity of the slurry, ensures

that consistent dosage of the

flavoring is maintained at all

times.

Sanitary Food Grade

Peristaltic pumps enable prod-

ucts as diverse as soft fruit and

food ingredients, as well as sub-

stances containing high concen-

trations of hard solids in a slurry

mix to be pumped and sprayed

on ingredients mixed in a hori-

zontal mixer. By virtue of their

construction, peristaltic pumps

are easily incorporated into full

velocity CIP (clean-in-place) or

SIP (sterilization-in-place) sys-

tems without the need for a by-

pass, whilst the pumping action

ensures that the hose is fully

swept with no crevices or dead

spots where product residues can

accumulate.

Slurry Pumps - figure 2 are capa-

ble of pumping more abrasive

thickened fluids with concentra-

tions as high as 80% solids for

product mixing in industries

such as pharmaceutical and bio-

tech, chemical, waste/water

treatment, mining, pulp and pa-

per, ceramics, food and beverage

and paints and pigments. They

operate using less water and

energy consumption.

Diaphragm Pumps - A positive

displacement pump that uses a

combination of the reciprocating

action of a rubber, thermoplastic

or Teflon diaphragm and suitable

non-return check valve to pump

a fluid.

Sometime this type of pump is

called a membrane pump. They

can handle sludges and slurries

with a good amount of grit and

solid content. Diaphragm pumps

are low shear pumps that can

handle highly viscous liquids.

High Pressure Pumps - Fig. 4

High pressure pumps accommo-

date more force in a smaller

package. At lower pressures, the

pumps provide the life and per-

formance margin essential in

critical environments. They also

provide a relatively large flush-

ing path for any system contami-

nation. This makes the pumps

ideal for systems where the fluid

cannot be totally cleaned by

filtration, or where it is just not

economical.

Choosing the Right Pumping System

Page 2

Liquid Spray Mixing Systems

Figure 1 - Peristaltic Pump

Their lack of valves, seals and

glands makes them compara-

tively inexpensive to maintain,

and the use of a hose or tube

makes for a relatively low-cost

maintenance item compared to

other types of pumps.

Figure 2—Slurry Pump

Slurry pumps minimize shear

forces experienced by the fluid,

which may help to keep col-

loids and slurry fluids from

separating.

“Having an effective

pumping system is

essential to the overall

performance of

the spraying system”.

Figure 3 - Continuous horizontal mixer with peristaltic pump (yellow) &

exterior piping, valves and tubing connect to the interior spray manifold

system. This mixing system blends liquid fragrances & talc powder.

Figure 4 - Hydraulic Pump

High pressure hydraulic and

piston pumps efficiently supply

flow in a circuit with changing

flow and pressure require-

ments.

Cleaning-In-Place (CIP) and

Sterilization-In-Place (SIP) are

systems designed for automatic

cleaning and disinfecting with-

out major disassembly and as-

sembly work.

CIP and SIP is vital to many

industries including Meat &

Poultry, Dairy, Baking, Produce,

Beverage, Fish, Confectionary &

Spices, Pharmaceutical,

Nutraceutical, Plastics, Cosmet-

ics and many more.CIP and SIP

are systems designed for auto-

matic cleaning and disinfecting

without disassembly and assem-

bly. This is important to many

industries where the processing

must take place in a hygienic or

aseptic environment.

Fluid-driven trough vessel noz-

zles as shown in figure1 are

especially suited for CIP

systems—no motor source is

needed due to the reactionary

force of the cleaning liquid to

rotate the spray head. Spray

angles range from 180° to 360º

to meet most application needs.

Due to their low impact and

ability to withstand harsh

chemicals, they are best-suited

for final rinse or sanitation

applications and can be cali-

brated to a variety of flow rates

and pressures to achieve the

required impact. Other features

include:

Rotating and fixed designs

Sanitary Lances

Reduced water and chemi-cal use with high-impact cleaning.

Eliminates post-cleaning tests.

CIP/SIP Systems

Combine Multiple Processes in One Mixer

Control Agglomerates with Spray Adjustments

liquid is added. For example,

adding the liquid from multiple

points instead of just a single

point, or optimizing the liquid

stream, will help prevent lumps.

In some applications adding high

-speed shoppers will also help.

Liquid slugging will create wet

spots or lumps that need to be

dispersed or broken up. Opening

and exposing the material

surfaces will enable uniform

particle coating. If the mixer is

unable to break the lumps, try

spraying in the liquids with a

liquid spray manifold system

because smaller droplets are

easier to break up.

Specification and position of

spray nozzles is challenging.

With liquid addition, the mate-

rial may become stickier and

stick onto the equipment also

causing agglomeration.

A lump forming in a mixer is an

agglomerate, which occurs when

particles are held together by a

bridge and the bonding of the

bridge is stronger than the parti-

cle weight. You need to elimi-

nate the bridging to breakup or

eliminate lumping in a mixer.

If you are adding liquid to the

mixer, especially liquid binders

try changing how or where the

Page 3

Spraying Systems & Mixing

Figure 1 - Shows The extended CIP

trough cleaning nozzle positioned to

clean and sanitize the interior chamber

of the mixer.

“New mixer equipment

is designed to improve

productivity by

consolidating

manufacturing

processes in a single

vessel.”

Figure 2 - Shows agglomeration

caused by the mixing of improper

spray droplets and the collision of

particles.

Stop wasting…...start saving.

New mixer designs now improve

productivity considerably by

consolidating numerous proc-

esses into a single vessel. Cus-

tom design mixer manufactures

create equipment that is capable

of doing more than just blend

ingredients. This will help to

lower your capital equipment

expense budget.

The following accessories allow

processors to combine multiple

processes in one mixer:

High Intensity Choppers

ASME Code Rated Jackets

Electrical Controls

Load Cell Weigh Equipment

Pumping Systems

Bag Dumps, Surge Bins,

Weigh Hoppers

Mezzanine Structures and

Bucket Elevators

Liquid, Gas and shortening

systems

Air Supply Manifolds

Improving spray nozzle perform-

ance and extending nozzle life

through proper maintenance is

critical to optimizing any spray

system.

As nozzle orifices wear, the

liquid flow increases or the

spraying pressure drops, result-

ing in larger drop sizes. Larger

drops result in less total liquid

surface area affecting agglom-

eration. 7 reasons why spray

nozzles don’t perform properly:

1. Erosion/wear

2. Corrosion

3. High Temperature

4. Caking/Bearding

5. Accidental Damage

6. Clogging

7. Improper Assembly

Optimization:

When your spray system isn’t

performing optimally, you can

experience a wide variety of

problems—all of which will cost

you time and money. For exam-

ple, you could experience:

Quality control issues

Unscheduled Production

downtime

Increased maintenance

Increased consumption of

costly chemicals, water and

electricity

If your present mixing system

isn’t performing properly, you

could experience significant

costs in labor, increased scrap

and lost production time.

Automation:

The most efficient way to

process liquid spray applications

is with an automated system that

uses a controller to “manage”

performance, Figure 3.

Control Panels - Motor controls

are custom designed, assembled

and tested at our factory. Explo-

sion proof and wash down de-

signs are available. Each control

panel is made with various elec-

trical and safety control features

and wired for 230/460 volt 3-

phase capacity.

Each installed control panel is

energized and operated to

inspect the equipment installa-

tion and process parameters.

Optimization & Automation

Page 4

Liquid Spray Mixing Systems

Figure 1 Shows the side view of the

liquid spray manifold system in

operation.

Figure 3 - Automated control panel used

in coloring wood chips. Select functions

include: tote, conveyor, auto, color, water

and mixer.

“When your spray

system isn’t performing

optimally, you can

experience a variety of

problems costing you

time & money.”

Figure 2 Shows the top-side view of a liquid spray manifold system in operation. Multiple nozzle spray ports with

adjustable, precision-controlled spraying will canvas the product envelope for a thorough spray application.

The two ingredients used to

make pasta are semolina wheat

and water. Mixed properly

(granulometry) the absorbed

semolina will produce a high

quality glutinous consistency

suitable for pasta dough manu-

facturing.

The kneading of the dough and

the mixing of the water into the

dough are both important steps

in processing.

The liquid spray process consists

of the following components:

Liquid Addition Manifold

¾” T304 stainless steel pipe

One end fitted with ball

valve for cleanout.

Opposite end threaded to

liquid injection devise.

Two (2) stainless steel

floodjet wide angle, low

impact flat pattern spray

nozzles arranged to provide

even spray pattern across

the mixer with minimal

wetting of agitator

components.

Liquid injection devise

consists of an optional

ASME pressure dispensing

tank or connection to mu-

nicipal water source.

uid metering system, a forced air

drying system and two bulk

material conveyors. Chunks of

ground rubber are loaded into

the mixer from pre-weighed

super sacks. Undiluted, latex

paint is volumetrically metered

into the mixer. The mixer’s pad-

dle-style agitators evenly coat

the rubber. A variable speed

A Midwestern tire recycling

company uses a custom designed

mixer to coat chunks of car tire

with a latex colorant. After ap-

plying the colorant, the mixer

dries the colorant to prevent rub-

off.

The mixer includes a batch

sequencing control panel, a liq-

controller slows the speed of the

mixer shaft to avoid scrubbing

the latex chunks during the dry-

ing cycle. Air is then blown

through the materials creating a

fluidized bed of ingredients to

prevent the materials from stick-

ing together during the drying

process.

Pasta Dough Mixing Machine

Rubber Mulch Coloring & Drying Mixer

Page 5

Figure 1 Shows a 300 lb. batch Pasta

Dough machine suitable for dry or fresh

Figure 2 Shows Tire recycling mixer with

automated colorant system.

Liquid Spray Application Gallery

Flyash Conditioning Mixer

age sludge, gypsum from flue

gas desulphurization systems,

filler for construction used in

lightweight aggregates and res-

ins in the production of high-

carbon fuel.

Today fly ash conditioning sys-

tem are designed to blend bio-

solids and other biomass feed-

stock's as well as condition fly

ash with water to allow the mate-

rials to be transported at 10-15%

moisture without emitting dust in

a consistent homogenous mix.

This continuous mixer was de-

signed with a 360º cylindrical

trough, paddle-style agitator with

back mix with trough cleaning

actuators. Spray manifold uses

(2) 2” NTP nipples to discharge

an even spray of water to mixer.

In Class F and Class C fly ash

conditioning both batch and

continuous mixers can be used

for conditioning fly ash while

containing fugitive dust during

the stabilization of waste materi-

als.

Other similar applications using

liquid injection systems include:

high-grade concrete products,

fertilizer from neutralized sew-

ILASS

www.ilass.org

Spraying Systems Inc.

www.spray.com

Marion Mixers, Inc

www.marionmixers.com

Watson-Marlow Pumps Group

www.watson-marlow.com

BETE Fog Nozzle

www.bete.com

Wiley-VCH

www.wiley-vch.de

Other Rsources