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Balanced-Pressure Fillers. The ﬁrst three of the seven

mentioned above are balanced-pressure ﬁllers, in which

product ﬂows through a valve into the container from a

tank of liquid located above the container, and air from the

container is vented back to the headspace in the tank

through the same valve. The typical embodiment of such a

ﬁlling system, gravity ﬁlling—one of the simplest and

most reliable—is illustrated in Figure 1. As the ﬁlling

takes place through the sleeve-type valve illustrated,

liquid ﬂows from the tank through the liquid port into

the container, and air within the container ﬂows up the

vent tube to the top of the tank. The container ﬁlls product

to an exact level determined by the position of the vent

port relative to the bottle. Any liquid in the vent from a

previous ﬁlling cycle is returned to the product in the tank

by the air ﬂowing up the vent tube. If necessary, air or

vacuum may be used to clean the vent before the start

of ﬁll.

A modiﬁcation of pure gravity ﬁlling is the gravity–

vacuum ﬁller. In such a system, a low vacuum is main-

tained in the headspace in a sealed tank. When the

container is brought into sealing contact with the ﬁlling

valve and the valve is opened, the pressure of air in the

container helps force any product in the vent back into the

tank, accelerating the start of the ﬁlling process. The use

of gravity–vacuum ﬁllers also prevents the loss of product

that would occur if a chipped or slightly broken container

were ﬁlled. This savings is of particular advantage when

ﬁlling more expensive products.

To ﬁll thin-walled plastic containers, such as 1-gal (3.8-L)

milk bottles , a pulsating vacuum in the tank is sometimes

used to cause the container walls to ﬂex in and out, assisting

the foam in moving up the vents . The pulsations must be

timed so that a container is not ﬂexed inward at the position

at which it is ready to break away from the ﬁlling valve,

because this could cause underﬁll.

Thousands of different styles of ﬁlling nozzles, which

use single ports, multiple ports, screens, sliding tubes, or

check valves, are offered by various manufacturers. All

these styles are designed to achieve the maximum produc-

tion rate with the fewest number of ﬁlling valves and

provide greater accuracy of ﬁll. The selection of nozzle

type is probably best left to the judgment of the machinery

manufacturer, on the basis of experience and product

testing.

Counterpressure ﬁllers for carbonated beverages are

discussed elsewhere (see the Filling machinery, carbo-

nated liquid article).

Unbalanced-Pressure Fillers. Unbalanced-pressure ﬁl-

lers use a difference in pressure between that on the

liquid to be ﬁlled and on the vent that permits air in the

container to escape during the ﬁlling process. The usual

combinations are listed in Table 1. The use of unequal

pressure permits higher rates of product ﬂow than possi-

ble with the balanced-pressure ﬁllers. Unequal pressure is

particularly advantageous when ﬁlling containers with

small openings, viscous products, or large containers.

Unbalanced-pressure ﬁlling has the disadvantage of

requiring an overﬂow-collection/product-recirculation

system, in contrast to the relative simplicity of balanced-

pressure ﬁllers. Higher liquid-ﬂow rates do not necessarily

result in faster ﬁlling because the additional foam gener-

ated by rapid entry of product into the container must be

drawn off through the overﬂow system to obtain accurate

ﬁlling-level control.

A schematic diagram of a typical vacuum ﬁller is shown

in Figure 2. The supply tank may be located either above

or below the container to be ﬁlled. After the ﬁlling valve

seals against the container and the valve opens, the

vacuum on the vent draws the liquid into the container

up to the ﬁlling level. Usually, a substantial quantity of

Figure 1. Pure gravity ﬁlling. (Courtesy of Horix.)

Table 2. Container Positioning Methods

and Conﬁgurations

Positioning Method Conﬁguration

Manual

Automatic, in-line Single or dual lane

Automatic, rotary Single or dual lane

Figure 2. Pure vacuum ﬁlling. (Courtesy of PMMI.)

448 FILLING MACHINERY, LIQUID, STILL

liquid is drawn into the vent, which leads to an overﬂow

tank. Product is recovered in the overﬂow tank and then

recycled.

The prevacuumizing ﬁller is a special form of vacuum

ﬁlling. On such a ﬁller, a vacuum is ﬁrst drawn in the

container, evacuating the air. The valve then permits

liquid to enter the container. Because such a system is

complex and expensive, it is normally used only when

liquid is being added to solids already in the container.

Certain solids, such as peach halves, trap air. Such air

entrapment may be eliminated by use of a prevacuumiz-

ing ﬁller.

In an unbalanced-pressure gravity ﬁller, the product-

supply tank and the overﬂow tanks are open to the atmo-

sphere, but the product tank is located above the container

and the overﬂow tank is located below the container,

permitting the differential pressure achieved by the dif-

ference in elevation to cause product ﬂow. Such a ﬁller is

necessarily rather restricted in its ability to adapt to

varying products and containers because the pressure

difference is established solely by the product-tank and

overﬂow-tank locations. Fillers of this type are not

common.

A pressure ﬁller is similar to a vacuum ﬁller except that

pressure is applied to the product. This may be achieved

either by pressurizing the headspace over a tank or by

direct pumping of the product to the ﬁlling valve. In the

most common form of pressure ﬁlling, the product is

pressurized, and the overﬂow tank is open to the atmo-

sphere. Such a system allows unbalanced ﬁll without

vacuum. This is desirable when vacuum cannot be drawn

on the product.

For example, drawing a high vacuum on alcoholic

beverages can reduce the alcoholic content of the bever-

age. Applying a vacuum to a hot product, such as juice at

2001F (931C) causes the liquid to ﬂash. If desired, both the

product and the vent can be maintained above atmo-

spheric pressure, but with a higher pressure on the

product. Such a ﬁller is often used for ﬁlling lightly

carbonated products, such as certain wines, using the

pressure to retain the low carbonation in the product.

Unsealed Container Filling Systems.

Level-Sensing Fillers. Level-sensing ﬁllers ﬁll containers

to a controlled level without sealing the container, as

shown in Figure 3. Such a ﬁlling technique eliminates

product recirculation and allows ﬁlling to a level in plastic

containers that would bulge out or ﬂex inward if pressure

or vacuum were applied to the sealed container. A level-

sensing ﬁller uses some type of sensing means, typically a

ﬂow of ultra-low-pressure air. The rising liquid level in the

container blocks air-ﬂow, triggering a control system that

shuts off product ﬂow to the container. Such control

mechanisms, which are required at each ﬁlling nozzle,

are expensive, but high rates of ﬁll may be achieved

because there is no product overﬂow and no foam to be

removed. Electronic sensing is also available.

Piston Volumetric Fillers. Currently, unsealed-container

ﬁllers are the most common, and volumetric ﬁlling is a

frequently used method. In view of this popularity, many

different kinds of volumetric ﬁllers are available. For

volumetric ﬁlling, piston ﬁllers are most widely used.

Table 1 indicates four subclasses of piston ﬁllers, depend-

ing on the orientation of the pistons, speciﬁcally vertical or

horizontal, and inlet arrangement.

1. Cylinder Vertical, Closed Ends. One station of a

typical vertical-cylinder rotary ﬁlling machine is

illustrated in Figure 4. The valve(s) controlling the

product ﬂow between the supply tank, measuring

chamber, and dispensing nozzle may have either a

rotary or a reciprocating motion. The rotary style,

which is more common, is illustrated. The product is

drawn into the cylinder from the liquid-supply tank

when the piston moves upward. The valve then

rotates to permit the premeasured volume in the

cylindrical chamber to ﬂow into the container.

Usually, either a direct mechanical drive from a

cam track or an air cylinder is used to stroke the

piston. If an air cylinder is used to drive the piston,

controls are usually such that the piston does not

cycle if a container is not in place. This eliminates

moving the liquid back and forth between the mea-

suring chamber and the supply tank, a situation

that is usually undesirable and may cause product

breakdown with foods such as mayonnaise. It is not

easy to uncouple a mechanically driven piston.

2. Cylinder Vertical, Open-End Inlet. In an alternative

design, product enters vertical volume chambers

through cylinders open at their upper ends, with a

cam drive located below. A nonrotating plate with an

oriﬁce allows product to enter the open-ended cylin-

ders at the appropriate position during the rotation

of the ﬁller bowl. Such a conﬁguration is mechani-

cally complex and generally considered difﬁcult to

clean.

Fillers of this

type have the advantage, how-

ever, of being able to handle products containing

sizable solids in suspension.

Figure 3. Level-sensing ﬁlling. (Courtesy of PMMI.)

FILLING MACHINERY, LIQUID, STILL 449

3. Cylinder Horizontal. Measuring cylinders may be

mounted horizontally. Usually single-ended, they

are similar to vertical cylinders in operating princi-

ple. They are frequently found on in-line, large-

volume ﬁllers to avoid excessive height for such

machines. A volume cylinder may also be double

ended, with inlets and outlets at both ends. Product

under pressure ﬂows into one end, which causes a

ﬂoating piston to move and expel the liquid in the

opposite end of the cylinder into the container. In

some ﬁllers, the double-acting cylinder may be used

for a single ﬁll, and the ﬁrst half of the ﬁll comes

from one end. The ﬂow pattern is then reversed to

discharge product from the other end of the cylinder

for the second half of the ﬁll while the ﬁrst end is

being ﬁlled for the next cycle.

Rolling-Diaphragm Volumetric Fillers. The volumetric

ﬁllers described above normally have some type of a

seal, such as V or O rings, between the pistons and

cylinder walls. An alternative method for measuring

volume is to use a rolling diaphragm; a typical arrange-

ment can be observed in Figure 5. The diaphragm pro-

vides an absolute seal and also eliminates the friction

contact of a seal with a cylinder wall. Such sliding causes

abrasion and particle generation, which is seldom impor-

tant, but minimizing particulate generation is important

in the packaging of intravenous solutions and injectable

drugs. Rolling-diaphragm volumetric ﬁllers often employ

ﬂexible diaphragms or pinch valves to control product ﬂow

to and from the measuring chambers.

Displacement-Ram Volumetric Fillers. Another method

for dispensing a speciﬁc volume of liquid is to use a

displacement ram. The ram enters one end of a cylinder

through a seal of some type, but the displacement ram

does not touch the inside of the cylinder wall. An external

air cylinder drives the ram, which displaces a controlled

volume from the cylinder into the container. Such ﬁllers

are easy to clean.

Volume-Cup Fillers. Cup-type volumetric ﬁllers operate

by ﬁrst transferring the product from an open tank into

measuring cups of precise volume. Depending on the

design, each cup may be ﬁlled to a level matching that of

the tank, or the cup may ﬁll to overﬂow and then rise

above the level of liquid in the tank. Each valve then opens

at the bottom, permitting liquid to ﬂow from the cup into a

container. Although such ﬁllers are appropriate only for

low-viscosity liquids that do not cling to the sidewalls of

the cups, for suitable applications the volume-measuring

method is accurate, inexpensive, and reliable. Various

volume-adjustment systems are provided. These ﬁllers

are usually rotary and are often designed to be easily

changed, by means of a change of ﬁlling valves, to gravity

or gravity–vacuum ﬁlling.

Turbine-Meter Volumetric Fillers. The amount of liquid

dispensed from a nozzle can be measured by placing a

turbine ﬂowmeter in the line ahead of the nozzle. Such

meters, which include an electronic counting and control

system to start and stop ﬂow, are accurate but expensive

and are generally used only for ﬁlling large containers,

i.e., Z5 gal (Z19 L).

Figure 4. Piston volumetric ﬁlling. (Courtesy of PMMI.)

Figure 5. Rolling-diaphragm volumetric ﬁlling: (1) volume ad-

justment rod; (2) precision volume adjustment; (3) quick-discon-

nect design; (4) volume-chamber diaphragm; (5) product tube; (6)

valve seats; (7) product supply manifold. (Courtesy of Horix.)

450 FILLING MACHINERY, LIQUID, STILL

Positive-Displacement Volumetric Fillers. Viscous liquids

may be moved directly from a supply system through a

positive-displacement pump into a container. Volumetric

measurement is achieved by accurately controlling the

number of revolutions made by the pump. An auger may

be used as the pump mechanism.

Peristaltic-Pump Volumetric. Peristaltic pumps are of-

ten used to ﬁll sterile liquids, as they are easy to clean and

have no sliding parts that might contaminate the product

being ﬁlled.

Weight Fillers. On gross-weight ﬁllers, each ﬁll station

is ﬁtted with a weighing device, typically a beam scale,

which acts to shut off product ﬂow when a predetermined

weight has been reached. Each scale is set for the max-

imum weight of container and contents. Adjustment for

other containers and content weight may be made by

adding special weights to each ﬁlling platform.

By using a load cell as the weighing device, the weight

is electronically measured continuously, and liquid ﬂow is

stopped at a predetermined weight. With microprocessor

controls, the change from one weight to another is simple.

Net-weight ﬁllers employ more advanced load-cell weigh-

ing devices. The tare weight of each container is mea-

sured, and then product ﬁll proceeds until the proper net

weight is in the container. Net weight ﬁlling is the most

accurate method for ﬁlling free-ﬂowing products. Such

ﬁllers are readily available with simple, easily cleanable,

nonsliding contact valves. They are usually relatively

expensive, as each ﬁlling station requires a load cell and

its associated electronic interface. But, such costs are

often justiﬁed by the reduction of product overﬁll possible

with the increased accuracy.

Time-Fill Fillers. Time-ﬁll ﬁlling consists of delivering

liquid under pressure to an oriﬁce that is open for a

controlled length of time. Such a ﬁller may be either of

the controlled-pressure-head type or the constant-volume-

ﬂow type. On multistation controlled-pressure-head ﬁl-

lers, which are most frequently in-line, all oriﬁces are

opened for approximately the same length of time. Minor

adjustments may be made at each station to compensate

for individual oriﬁce characteristics. Until recently, such

time-ﬁll ﬁllers depended for their accuracy on maintaining

a precise pressure head on the liquid at the oriﬁce. This

was achieved with pressurizing tanks or a liquid level

established by ﬂowing the product over a dam. Small

pressure ﬂuctuations are now acceptable, because a mi-

croprocessor controls the time each oriﬁce is open, on the

basis of measured pressure variations. Such ﬁllers are

designed for easy cleaning and changeover from one

product to another. To date, such ﬁllers have not generally

been used for high-speed production runs. They are prob-

ably best suited to ﬁlling pint (473 mL) or smaller contain-

ers with free-ﬂowing liquids.

The constant-volume-ﬂow type of time ﬁller is almost

always adapted to a rotary ﬁller. In a typical embodiment

(see Figure 6), product is delivered continuously to the ﬁller

at a constant ﬂow rate, using constant-displacement

pumps or their equivalent. The amount of product entering

each container is proportional to the length of time a nozzle

is under the liquid ports. The time is determined by the

rotational speed of the ﬁller. Constant-volume-ﬂow time

ﬁllers are relatively simple and inexpensive. They are

capable of reasonable accuracy, particularly with products

of medium to high viscosity. Leakage between plates is

hard to control with low-viscosity liquids. The product ﬂow

must be simultaneously altered any time the ﬁller is

stopped or started. It is difﬁcult to do this and maintain

consistent ﬁlling accuracy. Because a no-container/no-ﬁll

mechanism is rarely provided, any missing containers

cause product overﬂow, which must be collected and either

returned for reuse or discarded.

Overﬂow Fillers. Some products can be ﬁlled by ﬁlling

open containers, usually sanitary cans or widemouth glass

bottles, to overﬂow. The liquid may ﬂow from a pipe or

over a barrier. In more advanced overﬂow ﬁllers, the liquid

ﬂow into open containers is directed by moving funnels

synchronized with the movement of containers. The head-

space in the container, which is typically small, may be

established in various ways. When brine is added to

pickles, for example, the headspace is usually created by

displacement pads that enter the container and establish

the desired headspace. If solids are present, then the

headspace pads also ensure that the solids are properly

down into the container. Another method of establishing

headspace is to tilt the containers slightly, permitting

liquid to pour out. With some overﬂow ﬁllers, an upwardly

directed curtain of air prevents the overﬂowing liquid

from contacting the outside of the containers. With careful

adjustment of liquid ﬂow rate and container speeds, the

amount of ﬂuid that is overﬂowed and recirculated may be

limited to a very small proportion. Tilted-container over-

ﬂow ﬁllers are relatively fast and inexpensive. They are

frequently used for ﬁlling juice in cans, but they normally

cannot be used to ﬁll narrow-neck containers.

CONTAINER POSITIONING

Filling machines may be characterized by the way they

deliver containers to the liquid-dispensing mechanisms

and remove them after ﬁlling (see Table 2).

Figure 6. Constant-volume-ﬂow time ﬁlling. (Courtesy of

PMMI.)

FILLING MACHINERY, LIQUID, STILL 451

Manually Loaded Fillers. The oldest and simplest

method of container delivery and removal is by manual

means. Filling occurs after one or more containers are in

place. The containers may be raised to the ﬁlling valves or

the valves lowered to the containers, or no relative motion

may be required. Because of the amount of labor involved,

manual ﬁlling is usually limited to small production runs.

In-Line Fillers. The simplest automatic ﬁllers are single-

lane in-line machines. In a typical machine of this type,

containers, standing on a conveyor, are delivered to the

ﬁller. One or more containers back up behind a stop or

gate. The barrier then opens, and a controlled number of

containers move under the ﬁlling heads, where they are

positioned by another barrier of some type. Conveyor

motion is usually intermittent, with the conveyor stopped

during the ﬁll cycle to prevent tipping the containers.

After the ﬁlling is completed, the positioning barrier

opens, and the ﬁlled containers leave while unﬁlled

packages enter.

The size and shape of a container are factors that

determine how many containers may be ﬁlled simulta-

neously on an in-line intermittent-motion ﬁller. Increas-

ing the number of ﬁlling stations increases the total

output of the machine, but this approach runs into space

limitations and at a certain point, an additional valve is

not cost-effective. Sixteen stations seem to be the max-

imum commercially feasible number of valves. If the

containers are not straight sided, then there usually is

difﬁculty in backing up any signiﬁcant number behind a

positioning stop; even with straight-sided containers, the

process is limited by container dimensional tolerances.

The size of the containers determines the position of the

last container in a row relative to the ﬁrst container. If the

lead container is not properly positioned under a nozzle,

then the accumulation of container dimensional toler-

ances may cause the trailing container not to be positioned

under a nozzle.

An in-line ﬁller may be used for in-case ﬁlling. A

multiple array of ﬁlling valves is used to ﬁll all the

containers in a case at the same time. As with individual

containers, two or three cases may be backed up for

simultaneous ﬁlling. Such ﬁlling is possible only if the

cases have reasonably consistent dimensional control.

A variation of in-line intermittent-motion ﬁlling is occa-

sionally used to raise the containers relative to the ﬁlling

nozzles. This is done (e.g., in ﬁlling mayonnaise or peanut

butter) to change the position of the container relative to

the nozzle during ﬁll. On such a ﬁller, the containers are

moved by means of a pusher mechanism from the infeed

conveyor onto a platform under the ﬁlling heads, and the

platform is then raised. After the containers have been

ﬁlled and the platform lowered, successive unﬁlled contain-

ers may be used to push the ﬁlled packages onto a

discharge conveyor running behind and parallel to the

infeed conveyor, or individual mechanisms may move the

containers between the infeed and discharge conveyors.

Some manufacturers offer a rising-platform device with a

straight-through conveyor arrangement.

Dual-lane straight-line ﬁllers permit more efﬁcient

utilization of ﬁlling stations. Containers move on two

parallel conveyors. The ﬁlling nozzles, in a row, ﬁll in

one lane while container movement occurs in the other

lane. The use of dual-lane ﬁllers is generally considered

only if the limit of the number of valves in a single lane

has been reached. They are typically used for small

containers because ﬁll time is short relative to the time

required for container movement.

Valve use is the percentage ratio of actual ﬁlling time,

i.e., the time the valve is fully open, to the total cycle time

for that valve from the beginning of ﬁlling one container to

the start of ﬁlling the next container. Valve use is low on

in-line ﬁllers, i.e., 25% to 50% of cycle time, dependent on

conveyor speed, container diameter, and actual unit-ﬁlling

time required for the ﬁll.

Rotary Fillers. The most common system for ﬁlling

containers are moderate to high speeds is rotary ﬁlling.

Containers arrive continuously on a conveyor and are

spaced by some means into a rotating infeed star that

delivers them, properly separated, to ﬁlling stations on the

main rotary assembly. The timing mechanism normally

employed to take containers coming at random to the ﬁller

is a feed screw; for large containers and low-speed opera-

tion, timing ﬁngers, escapement wheels, or like devices

may be used. The discharge from the main rotary is

usually by means of a second star wheel with the same

diameter as the ﬁrst. However, if the liquid level is high in

the container, either a large-diameter star or a tangential

conveyor should be used to prevent spill.

On rotary ﬁllers, valve utilization is almost indepen-

dent of container size but is a function of ﬁller diameter.

For example, a 22-in. (56-cm)-pitch-diameter gravity ﬁller

for 32-oz (946-mL) containers has a valve utilization of

49%, whereas a similar gravity ﬁller having the valves on

a 60-in. (152-cm) pitch diameter has a valve use of 73%.

The time that the valve is closed is necessary for the

transfer of containers into and out of the rotary section

and for the relative movement between container and

ﬁlling valve needed to open and close the valve.

The concept of dual-lane rotary ﬁllers, involving two

lanes (inner and outer) on the main rotary, was proposed

and patented many years ago. Except, perhaps, for large-

diameter carbonated-beverage ﬁllers, the system is not

practical. Two infeed stars and two discharge stars (or a

tangential system) would be needed, and such an arrange-

ment greatly reduces valve use. The fact that valve

spacing is limited in the inner row is a disadvantage as

well, unless unequal production speeds are desired. In one

conﬁguration study, the valve use on an 80-valve, dual-

lane, 60-in. (152-cm)-outer-lane-pitch-diameter machine

only 66%, compared

with the normal 85% use of a 48-

valve, 60-in. (152-cm)-pitch-diameter ﬁller. Adding 67% in

number of valves adds only 29% to the production

capability.

Continuous-motion in-line ﬁllers use a timing screw to

position the containers under multiple ﬁlling heads, which

move in synchronization with the containers.

Multihead in-line weight ﬁllers may have a conveyor

system that separates and stops a group of containers.

Weighing platforms then lift the containers above the

conveyor for the ﬁlling cycle. Alternatively, they may use

452 FILLING MACHINERY, LIQUID, STILL

a lateral transfer device to place the containers on the

scale platforms.

Relative Motion. The relative motion between the con-

tainer and the liquid-dispensing device can signiﬁcantly

affect ﬁller performance. The various relative motions

possible are none, raise container, lower valve, and raise

container and lower valve.

In sealed-container ﬁlling (see Table 1), relative motion

between the container and the valve is required to bring

the valve into contact with the container. With manual

container placement, the container can be raised against

the valve, or the valve(s) can be lowered to one or more

containers on platforms.

The valve use of rotary sealed-container ﬁllers can be

increased by lowering the valve (see Figure 7). With a

descending valve, the valve can begin to enter the con-

tainer at position 1, and it must be clear of the container at

position 1u. If the container is to be raised up to the valve,

the rise may not begin until position 2 because space must

be allowed for the container platform to clear the infeed

star. Likewise, the container platform must be in the full-

down position by position 2u. As an example, with 40

valves on a 60-in. (152-mm) pitch diameter, arc 1–1u is

327, whereas arc 2–2u is 306. This 6% difference may be

advantageous, but movement of each valve imposes other

difﬁculties on ﬁller design, often including the need for a

ﬂexible liquid connection to each valve. Such ﬂexible

connections often make cleaning more difﬁcult. The com-

bination of raising the container and lowering the ﬁlling

valve is very rarely used, as it requires mechanisms for

moving both elements, with all the disadvantages of each

system.

In-line, sealed-container ﬁllers are rather slow and not

common, except for ﬁlling containers in a case. Most of

those available operate by lowering the valves to the

container, which permits the containers to remain on the

conveyor. As with sealed-container ﬁllers, level-sensing

ﬁllers require relative motion between the ﬁlling valves

and the container. Rotary level-sensing ﬁllers typically

raise the container; in-line ﬁllers bring the nozzle down to

the package.

Volumetric, weight, and time-ﬁll ﬁllers do not require

relative motion between the dispensing nozzle and the

package. Thus, for simplicity and economy, most of these

ﬁllers operate with the nozzle located above the container

opening. However, two principal exceptions are as follows:

1. In ﬁlling containers with relatively small openings,

such as long-neck plastic bottles, greatly increased

rates of ﬂow are possible if the product ﬂow emerges

from the side of the tube and is directed against the

container wall (see Figure 1). Filling straight down

into that style of container from above may cause air

entrapment with consequent possible splashout or

overﬂow at the end of the ﬁlling cycle. The lost time,

if any, required to raise the container or lower the

ﬁlling valve may be more than offset by the faster

ﬂow rates possible.

2. Viscous products such as mayonnaise and peanut

butter are best ﬁlled volumetrically using a ﬂow

tube open at the bottom. To prevent air entrapment,

the ﬂow tube is maintained at a position very close to

the rising surface of the liquid by lowering the

container during the ﬁlling cycle.

CONSIDERATIONS IN DESIGN AND SELECTION

OF FILLERS

Many factors must be considered in selecting ﬁlling

machinery. These include such obvious factors as operat-

ing and maintenance costs, efﬁciency, reliability, size,

speed, and materials of construction. Several considera-

tions, discussed below, are speciﬁc to liquid-ﬁlling machin-

ery and important to the satisfactory operation and use of

such equipment.

Accuracy. The accuracy of ﬁll is important for two

reasons: (a) it is necessary to comply with state or other

regulations as to labeled content [the regulatory agencies

generally refer to the ﬁlling tolerances recommended in

the National Bureau of Standards Handbook 44 (2)] and

(b) in addition to meeting legal requirements, however,

packagers of most products desire to keep overﬁll to a

minimum, thus minimizing product giveaway. Even with

relatively inexpensive products, the amount given away

with inaccurate overﬁlling on high-speed production lines

can usually justify the higher cost of purchasing more

accurate ﬁllers.

Changeover and Cleaning. As a part of operating costs,

the time and labor required for cleaning and preparing the

ﬁller for daily operation, changeover from one product to

another or one container to another, and cleanup at the

end of each day’s production should be carefully evaluated.

User needs may range from ﬁllers that operate 24 h per

day with no need for product or container-size change, to

ﬁllers

for 30-min production

runs, after which the ﬁller

must be completely sterilized and adjusted for a different

container size. Comments are made above concerning the

Figure 7. Rotary-ﬁller arrangement.

FILLING MACHINERY, LIQUID, STILL 453

inﬂuence of ﬁlling techniques. The manufacturer’s de-

scriptions of container-positioning methods contain com-

ments on cleanability, container-size ﬂexibility, and ease of

adjustment. Speciﬁc aspects of each ﬁller design must be

carefully considered in choosing the proper liquid ﬁller for

a particular application.

No-Container/No-Fill System. In general, it is desirable

to have a ﬁller equipped with some type of no-container/

no-ﬁll system. In most sealed-container ﬁllers, the ﬁlling-

valve mechanism is designed to automatically provide a

no-container/no-ﬁll system in conjunction with the action

of the container and the ﬁlling valve coming together.

Likewise, with most of the unsealed-container ﬁlling

techniques, a relatively simple container-detection device

can be used to prevent product ﬂow if no container is

present. The constant-volume time ﬁller does not permit

start or stop of product ﬂow, but means such as drains in

the container platform to catch the product ﬂow may be

provided. Alternatively, particularly on in-line ﬁllers, a

control system may be provided to ensure that a full row of

containers is present.

Drive Location. The location of the main drive for the

ﬁller should be considered in ﬁller selection. Usually, the

main motor drive, or, alternatively, a lineshaft synchroni-

zation system, is located near ﬂoor level. Thus, the heavy

drive components are conveniently supported and reason-

ably accessible for routine maintenance. Because the

splash of corrosive products may signiﬁcantly harm drive

components even if they are protected against splash,

some ﬁller manufacturers locate the main drive above

the product. This may not be desirable for ﬁlling food or

drug products because of the potential for product con-

tamination from drive lubricants.

Equipment Standards. Various industry-consensus stan-

dards are applicable in the United States:

ANSI B155.1-1994 Safety Requirements for the Construction,

Care, and Use of Packaging and

Packaging-related Converting Machinery,

American National Standards Institute

3-A Sanitary

Standard 17-06

3-A Sanitary Standards for Fillers and

Sealers of Single Service Containers for

Milk and Fluid Mild Products,

International Association of Milk, Food,

and Environmental Sanitarians; U.S.

Public Health Service; The Dairy Industry

Committee

The ﬁrst standard is general but applicable to ﬁllers.

The 3-A Standard is speciﬁcally for milk ﬁllers.

The packaging of certain products is regulated by

government agencies. The packaging of ﬂuid-milk pro-

ducts in the United States is usually regulated by local

(i.e., county or state) authorities. They normally adopt the

3-A Standards without modiﬁcation, but a few jurisdic-

tions impose their own requirements, usually stricter. If

fresh milk is packaged in ﬂexible plastic containers, then

the container is usually the legally speciﬁed measuring

device. In such cases, volumetric tolerances normally

follow the recommendation of the National Bureau of

Standards (2).

The packaging of liquids in meat and poultry establish-

ments subject to inspection by the United States Depart-

ment of Agriculture (USDA) Food Safety and Inspection

Service is governed by guidelines issued by the depart-

ment (3, 4). Equipment for packaging food and drug

products is regulated in the United States by the Food

and Drug Administration (FDA) (CFR Title 21, Chapter I),

and the packaging of distilled spirits by the Bureau of

Alcohol, Tobacco, and Firearms (BATF).

BIBLIOGRAPHY

1. The PMMI 1994–1995 Packaging Machinery Directory, Packa-

ging Machinery Manufacturers Institute, Washington, DC,

1994.

2. Speciﬁcations, Tolerances, and Other Technical Requirements

for Weighing and Measuring Devices, National Bureau of

Standards Handbook 44, NBS, U.S. Department of Commerce,

Washington, DC, 1987.

3. Accepted Meat and Poultry Equipment, Meat and Poultry

Inspection Technical Services, Food Safety and Inspection

Service, U.S. Department of Agriculture, Washington, DC,

May 1984, pp. 1–8.

4. Guidelines for Aseptic Processing and Packaging Systems in

Meat and Poultry Plants, Meat and Poultry Inspection Tech-

nical Services, Food Safety and Inspection Service, U.S. De-

partment of Agriculture, Washington, DC, June 1984.

General Reference

C. G. Davis, Product Filling, Vol 1. of Packaging Machinery

Operations, Packaging Machinery Manufacturers Institute,

Washington, DC, 1987.

FILM, CERAMIC COATED

NOE OBINATA

Toppan Printing Company

For food packaging, gas/moisture barrier property is one of

the key elements to provide longer shelf life of products.

Aluminum foils, aluminum-metalized ﬁlms, PVDC-coated

ﬁlms, or coextruded EVOH ﬁlms have played major roles

in barrier packaging. However, there are increasing de-

mands for more sophisticated packaging, such as trans-

parency, metal detector capability, microwaveability,

retortability, and environmental friendliness as well as

barrier properties. Ceramic-coated ﬁlms are capable of

meeting the demands and have become more and more

popular recently.

Ceramic-coated ﬁlms are AlOx- or SiOx-coated ﬁlms of

excellent barrier properties, having the potentially of

reaching almost the same levels of O

and H

O barrier

454 FILM, CERAMIC COATED

as aluminum foil (Figure 1). Besides barrier properties,

transparency is another important aspect of these ﬁlms.

Although the SiO

layer is somewhat yellowish, both the

AlO

and SiO

layers are clear, providing the marketing

advantage of allowing the consumer to see the product

inside the package and the quality control advantage of

more reliable visual inspection. These ﬁlms also have the

advantages of metal detector capability and microwave-

ability. Unlike aluminum foil or metalized ﬁlms, these

metal-free ﬁlms allow metal detectors to work properly

and do not cause arcing in the microwave oven. Recent

improvement also imparts these ﬁlms with the exciting

advantage of being retortable, with the durability to with-

stand the severe temperature and pressure conditions in

the retorting process. In the past, only metal cans, glass

containers, and aluminum–plastic pouches were retorta-

ble. Replacing the heavier and more bulky metal cans and

glass containers with packages made of ceramic-coated

ﬁlms can result in signiﬁcant cost /energy savings in

transportation and waste reduction. A comparison of

ceramic-coated ﬁlms and other barrier ﬁlms is shown in

Table 1.

A physical vapor deposition process is typically used

to form ceramic coatings. Figure 2 is an example of an

AlO

coating process. Aluminum is evaporated from a

crucible tank by electron beam heating and then reacts

with oxygen to form a thin layer of AlO

onto a substrate.

The process is done under high vacuum conditions to

achieve efﬁcient evaporation and deposition of the

material.

Good Poor

Poor

Good

EVOH

OTR

Metallized PET

PVDC-coated OPP

PVDC-coated PET

Ceramic-coated films

Al Foil

WVTR

Figure 1. Oxygen and water vapor barrier map of typical barrier

ﬁlms (1).

Table 1. Comparison Between Ceramic-coated and the Other Barrier Films, where



, W, and  are Excellent, Moderate,

and Poor, Respectively

Films

Moisture

Barrier

Oxygen

Barrier Transparency

Use of Metal

Detector

Use of Microwave

Oven

Retort

Treatment

Ceramic-coated

    

Aluminum foil



 



Aluminum-metalized



 



EVOH 

  

PVDC-coated WW

  

unwinder

rewinder

electron beam

irradiation device

crucible tank

coating

drum

tension roller

spreader roller

oxygen

electron beam

vaporized

aluminum

Figure 2. An example of an AlO

coating process.

FILM, CERAMIC COATED 455

Since its commercial introduction in 1989, the Toppan’s

GL ﬁlms (ceramic-coated ﬁlms with SiO

or AlO

coating)

have been a family of leading transparent barrier ﬁlms for

food packaging applications. Later in 2002, the Toppan’s

GX ﬁlms were introduced to provide higher gas barrier

(Table 2). The collection of the GL and GX ﬁlms now

provides (a) the gas/moisture/aroma barrier, (b) transpar-

ency, (c) printability, (d) capability of microwave ovens and

metal detectors, (e) retortability, and (f) environmental

friendliness suitable for a wide range of food packaging

applications. The GL/GX ﬁlms have been used for more

than 200 food and pharmaceutical products (Figure 3).

Driven by the demand for high-barrier transparent

ﬁlms, ceramic ﬁlms have become increasingly accepted

by packaging suppliers. Some major suppliers and their

products are listed in Table 3. Most of the products

are available in the United States and Europe. The

Mitsubishi’s Techbarrier

uses PVA as a base ﬁlm for

high oxygen barrier, but extra care must be taken against

moisture absorption under humid conditions. The Toyobo’s

Ecosyar

uses the two-component process of AlO

and

SiO

simultaneous coating. According to the supplier’s

catalogue, the two-component process could provide both

advantages of AlO

and SiO

, meaning that high density

and good barrier are from AlO

while ﬂexibility and high

impact strength are from SiO

Usage of ceramic-coated ﬁlms has steadily increased in

recent years. Their versatile characteristics meet chan-

ging demands of food packaging, such as higher barrier,

visibility inside the package, and retortability. In particu-

lar, retort applications will support expansion of using

ceramic-coated ﬁlms as consumption of retort-pouched

food has increased on a world basis. The major market

for ceramic-coated ﬁlms is in food packaging applications;

however, a recent trend suggests that the applications of

these ﬁlms for pharmaceutical and electronic products

could rise in the next future, although more improvement

of the ﬁlms may need to be made.

BIBLIOGRAPHY

1. Worldpak 2002, Proceedings of the 13th IAPRI Conference,

2002, CRC Press LLC, Boca Raton, FL, 2002, p. 410.

2. Functional material, Vol. 27, No. 3, p. 53 (2007).

Table 3. Major Suppliers of Ceramic-Coated Films and Their Products

Suppliers Products Barrier Materials Base Films

Toppan Printing GL, GX Films AlO

, SiO

PET, PA

Toray Barrialox AlO

PET

Dai Nippon Printing IB-Film AlO

, SiO

PET, PA

Mitsubishi Plastics Techbarrier

SiO

PET, PA, PVA

Toyobo Ecosyar

AlO

and SiO

(two-component process) PET

Alcan Ceramis SiO

PET, PA

Figure 3. Example of food packaging applica-

tions using GL/GX ﬁlms.

Table 2. Barrier Properties of GL/GX Films

(2)

Film O

(cm

/day/MPa) WVTR (g/m

/day)

GX 2.0 0.05

GL-AE 5.0 0.6

Films are laminated with LLDPE (60 mm).

TR measured at 301C and 70%RH, WVTR measured at 401C and

90%RH.

456 FILM, CERAMIC COATED

FILM, EDIBLE

JOHN M. KROCHTA

Food Science and Technology,

UC Davis, University of

California, Davis, Davis,

California

DEFINITION AND FUNCTIONS

Edible ﬁlms are stand-alone structures that have appear-

ance and protective functions similar to synthetic polymer

ﬁlms. However, they are comprised of edible proteins,

polysaccharides, lipids and/or resins, and other compo-

nents that render them edible. Thus, they can be con-

sumed with a packaged product, resulting in less

packaging that requires disposal. Also, since edible ﬁlms

are made from renewable resources, they contribute to

package sustainability.

Edible ﬁlms by convention have thicknesses r10 mil

(r254 mm), above which they would be considered sheets.

They can be used as food wraps, and some can be formed

as food casings or can be heat-sealed into pouches for food

products. Edible ﬁlms can also be formed as coatings

directly on the surfaces of food and pharmaceutical pro-

ducts, thus becoming a part of the product.

Present uses of edible ﬁlms include collagen casings on

sausages to inhibit moisture loss and oxygen transport

and provide structural integrity; hydroxypropylmethyl

cellulose (HPMC) pouches for premeasured food and

beverage ingredients; gelatin capsules for pharmaceuti-

cals to improve product appearance, structural integrity,

ingestibility and stability; and dissolvable breath strips

made from a number of different edible materials. Present

uses of edible ﬁlms as coatings include shellac and wax

coatings on fruits and vegetables to prevent moisture loss

and improve appearance; methyl cellulose (MC) and

HPMC coatings on fried foods to reduce fat update;

shellac, wax, and zein coatings on confections and drug

tablets to provide moisture resistance and improve ap-

pearance; and MC and HPMC coatings on drug tablets to

improve product stability appearance and ingestibility.

Edible ﬁlms and coatings are generally seen as having

considerable potential for applications far beyond present

uses for improving product quality and safety. In addition

to controlling moisture, oxygen, aroma, and/or oil transport

and protecting products from mechanical forces, edible

ﬁlms and coatings can act as carriers for edible antioxi-

dants, antimicrobials, and other additives. Furthermore,

edible ﬁlms can be positioned within food products as

separation layers to reduce migration of moisture, lipids,

and solutes from one food component to another.

In some instances, edible ﬁlms and coatings have poten-

tial for reducing use of synthetic packaging ﬁlms. However,

they are not intended to eliminate the need for nonedible

protective packaging. Rather, they are intended to work

with conventional packaging to improve product quality

and shelf life. To the degree that an edible-ﬁlm wrap, casing,

pouch, capsule, or coating functions to protect the product

from the environment, the amount and complexity of

nonedible protective packaging can be reduced, leading to

source reduction and improved recyclability. For example,

an edible pouch for premeasured dry milk powders used in

bakeries may only need a recyclable paperboard box as a

secondary package. Or, an edible oxyen-barrier coating on

roasted peanuts could eliminate the requirment for an

oxygen-barrier layer in a ﬂexible pouch, resulting in a

single-layer moisture-barrier package that is more easily

recycled. In addition, after packaging is opened, an edible

coating can continue to protect the product.

The objective of this article is to review the materials,

manufacture, properties, applications, and trends of edible

ﬁlms. The area of microencapsulation of food and drug

ingredients is not covered.

FILM COMPOSITION

Components of edible ﬁlms must meet the same rigorous

standards applied to all food ingredients. Materials used in

formation of edible ﬁms must be generally recognized as

safe (GRAS) for intended use or sanctioned by the U.S. FDA

Code of Federal Regulations or the U.S. Pharmacopoeia/

National Formulary (or equivalent). It is also necessary

that all edible ﬁlm components be included on the product

label, to provide information critical to consumers with

allergies or intolerances to particular food components.

Film Formers

Film-forming materials available for edible ﬁlms fall gen-

erally into the categories of polysaccharides, proteins,

lipids, and resins derived from plants and animals. Pro-

tein ﬁlm formers include collagen, gelatin, casein, whey

protein, corn zein, wheat gluten, and soy protein (1–4).

Polysaccharide ﬁlm-forming materials include cellulose

derivatives, starch and starch derivatives, carrageenan,

alginate, pectinate, and chitosan (5, 6). Layering and

blending of proteins and polysaccarides show potential

for optimizing ﬁlm properties (7–9). Films can also be

produced from purees of foods such as fruits and vegeta-

bles, which contain combinations of ingredients (10). The

polar hydrogen-bonding character of polysaccharides and

proteins produces ﬁlms that have (a) high moisture per-

meability, (b) low oxygen and lipid permeabilities at lower

relative humidities, and (c) compromised barrier and

mechanical properties at higher relative humidities. Ed-

ible lipids and resins include carnauba wax, candelilla

wax, beeswax, triglycerides (e.g., milkfat fractions), acety-

lated monoglycerides, fatty acids, fatty alcohols, sucrose

fatty-acid esters and shellac (11–15). Lipid and resin

materials are not polymers and, therefore, do not gener-

ally

form coherent stand-alone

ﬁlms. However, they can

provide gloss and/or moisture-barrier coatings on food or

drug surfaces, or they can constitute the moisture-barrier

component of a composite ﬁlm. Composite ﬁlms can con-

sist of either (a) a lipid layer supported by a polysacchar-

ide or protein layer or (b) lipid material dispersed in a

polysaccharide or protein matrix (16, 17).

Materials used for edible ﬁlms also have potential

for replacing synthetic polymers in some nonedible

FILM, EDIBLE 457